JP7814549B2 - Coil device and power conversion device - Google Patents

Description

The present disclosure relates to a coil device and a power conversion device.

For example, power conversion devices such as DC-DC converters are equipped with coil devices such as transformers and smoothing reactors. The coil devices installed in power conversion devices consist of a coil and a core. The core has the function of forming a magnetic path, which is the path of magnetic field lines generated by current flowing through the coil. In power conversion devices, direct current or alternating current voltage is applied to the coil of the coil device.

By setting the frequency of the AC voltage to a high frequency, it is possible to miniaturize the core and reduce the number of coil windings (turns), contributing to the miniaturization of the coil device. In recent years, in order to miniaturize coil devices and power conversion devices equipped with coil devices, switching elements capable of handling high switching frequencies of, for example, 1 kHz or more have been used as switching elements equipped in power conversion devices.

The heat generated when current is passed through a coil device can be broadly divided into Joule heat generated in the coil and heat generated in the core. Joule heat increases inversely proportional to the cross-sectional area of the wiring used as the coil. Therefore, if an attempt is made to use wiring with a smaller cross-sectional area in order to reduce the size of the coil device, the Joule heat generated in the coil device will increase.

In addition, when an alternating current flows, the skin effect causes the current to flow only near the surface of the wiring, increasing the electrical resistance of the coil device. As the frequency of the alternating current flowing through the wiring increases, the electrical resistance value increases monotonically.

Therefore, the higher the frequency of the AC voltage applied to the coil device is set to in an attempt to reduce its size, the higher the electrical resistance of the wiring of the coil device becomes due to the skin effect, and the more Joule heat is generated in the coil device.

For this reason, there is a demand for improved heat dissipation capabilities in coil devices to keep the temperature rise of the coil device, caused by Joule heat and other factors, below an allowable temperature. In other words, in order to reduce the size of coil devices, it is also necessary to improve the heat dissipation capabilities of the coil device. The coil device proposed in Patent Document 1 proposes a method of dissipating heat generated by the coil, particularly in the area inside the core, via the printed circuit board and the coil.

WO 2014/141670 A1

As mentioned above, in order to reduce the size of coil devices, it is necessary to improve the heat dissipation properties of the coil device.

This disclosure has been made as part of such development, and one objective is to provide a coil device that can improve heat dissipation, and another objective is to provide a power conversion device that applies such a coil device.

The coil device according to the present disclosure is a coil device having a coil unit. The coil unit includes one or more cores, a metal base substrate, a first winding portion, a second winding portion, and one or more cooling bodies. The core has a loop-shaped magnetic path. The metal base substrate is disposed in an inner region of the core surrounded by the core and an outer region of the core, and a first coil pattern and a second coil pattern are formed on the metal base body with an insulating layer interposed therebetween. The first winding portion includes the first coil pattern and is wound around the core in a manner passing through the inner region of the core. The second winding portion includes the second coil pattern and is wound around the core in a manner passing through the inner region of the core and is electrically insulated from the first winding portion. The cooling body includes a first cooling body joined to the metal base body on the side opposite the side on which the insulating layer is formed. The metal base substrate includes a first metal base substrate and a second metal base substrate. The first coil pattern is formed on the first metal base substrate. The second coil pattern is formed on the second metal base substrate. The first metal base substrate and the second metal base substrate are arranged to face each other in such a manner that an insertion portion through which the core is inserted is formed between the first metal base substrate and the second metal base substrate.

The power conversion device of the present disclosure is a power conversion device equipped with the above-mentioned coil device.

In the coil device according to the present disclosure, heat generated in each of the first and second winding portions located in the outer region of the core is dissipated to the first cooling body via the insulating layer and the metal base body. Furthermore, heat generated in each of the first and second winding portions located in the inner region of the core is also dissipated to the first cooling body via the insulating layer and the metal base body. This allows the heat generated in each of the first and second winding portions located in the inner region of the core to be dissipated to the first cooling body to the same extent as the heat generated in each of the first and second winding portions located in the outer region of the core. As a result, the heat dissipation performance of the coil device can be improved.

The power conversion device disclosed herein is equipped with the above-mentioned coil device, thereby improving heat dissipation.

1 is a circuit diagram showing an example of a power conversion device to which a coil device according to each embodiment is applied; 1 is an exploded perspective view showing an example of a power conversion device including a coil device according to a first embodiment; FIG. 2 is an enlarged exploded perspective view showing the structure of a coil device in the power conversion device according to the embodiment. 4 is a cross-sectional view taken along line IV-IV in FIG. 2 in the embodiment. 10A and 10B are diagrams for explaining the reason for providing slit portions in the metal base substrate in the embodiment. FIG. 2 is an exploded perspective view showing a current path of the coil device in the embodiment. FIG. 2 is an exploded perspective view showing an example of a variation of the power conversion device including the coil device in the embodiment. FIG. 10 is a cross-sectional view showing an example of a coil device according to a first modified example of the embodiment. FIG. 10 is a cross-sectional view showing an example of a coil device according to a second modified example of the embodiment. FIG. 10 is a cross-sectional view showing an example of a coil device according to a third modified example of the embodiment. 10 is a cross-sectional view showing an example of a power conversion device including a coil device according to a second embodiment. FIG. FIG. 10 is a cross-sectional view showing a coil device according to an example of a first modified example in the embodiment. FIG. 10 is a cross-sectional view showing a coil device according to another example of the first modified example in the embodiment. FIG. 10 is a cross-sectional view showing a coil device according to an example of a second modified example in the embodiment. FIG. 10 is a cross-sectional view showing a coil device according to another example of the second modified example in the embodiment. FIG. 11 is a cross-sectional view showing an example of a power conversion device including a coil device according to a third embodiment. FIG. 10 is a cross-sectional view showing an example of a power conversion device including a coil device according to a fourth embodiment. FIG. 10 is a cross-sectional view showing an example of a coil device according to a modified example of the embodiment. 10 is a partial plan view showing the positional relationship between a core and a metal base substrate in a power conversion device including a coil device according to a fifth embodiment. FIG. FIG. 10 is a partial plan view showing the positional relationship between a core and a metal base substrate in a coil device according to a first modified example of the embodiment. FIG. 10 is a partial plan view showing the positional relationship between a core and a metal base substrate in a coil device according to a second modified example of the embodiment. FIG. 13 is a perspective view showing an example of a power conversion device including a coil device according to a sixth embodiment. FIG. 2 is a partial plan view of a power conversion device including a coil device in the embodiment. 24 is a partial cross-sectional view taken along the line XXIV-XXIV in FIG. 23 in the embodiment. FIG. 2 is an enlarged exploded perspective view showing the structure of a coil device in the power conversion device according to the embodiment. FIG. 10 is a perspective view showing an example of a power conversion device including a coil device according to a modified example in the embodiment. FIG. 2 is a partial plan view of a power conversion device including a coil device in the embodiment. 28 is a partial cross-sectional view taken along the cross-sectional line XXVIII-XXVIII in FIG. 27 in the same embodiment.

First, we will explain a DC-DC converter as an example of a power conversion device that includes a coil device. Figure 1 shows an example of a circuit diagram of a DC-DC converter. DC-DC converters are installed, for example, in electric vehicles. DC-DC converters have the function of converting the input voltage of a lithium-ion battery, which is approximately 100V to 300V, into a voltage of 12V to 15V, and outputting the converted voltage to charge a lead-acid battery.

As shown in Figure 1, the DC-DC converter as a power conversion device 1 includes an inverter circuit section 2, a transformer section 3, a rectifier circuit section 4, a smoothing circuit section 5, an input terminal 6, an input capacitor 8, a control circuit section 10 and an output terminal 7.

The inverter circuit unit 2 is composed of switching elements 9. Here, the inverter circuit unit 2 is composed of four switching elements: 9a, 9b, 9c, and 9d. The switching elements 9 are, for example, power semiconductor elements such as MOS transistors (MOSFETs: Metal Oxide Semiconductor Field Effect Transistors) or insulated gate bipolar transistors (IGBTs: Insulated Gate Bipolar Transistors). The switching operation of the four switching elements 9 is controlled by the control circuit unit 10.

The transformer unit 3 is composed of a transformer 11 having a primary winding unit 11a and a secondary winding unit 11b. The rectifier circuit unit 4 is composed of a rectifier element 12. Here, the rectifier circuit unit 4 is composed of four rectifier elements: 12a, 12b, 12c, and 12d. The rectifier element 12 may be, for example, a power semiconductor element such as a diode, MOS transistor, or thyristor. The smoothing circuit unit 5 is composed of a smoothing reactor 13 and a smoothing capacitor 14.

In the DC-DC converter serving as the power conversion device 1, the DC voltage input from the input terminal 6 is converted into AC voltage by controlling the switching operation of each of the four switching elements 9 in the inverter circuit section 2 using the control circuit section 10.

In the transformer unit 3, the AC voltage converted in the inverter circuit unit 2 is converted to an arbitrary voltage by the transformer 11. The converted voltage is determined by the winding ratio between the primary winding unit 11a and the secondary winding unit 11b in the transformer 11. The transformer 11 electrically insulates the input terminal 6 from the output terminal 7.

In the rectifier circuit section 4, the AC voltage supplied from the transformer section 3 is converted back to DC voltage by the rectifier element 12. In the smoothing circuit section 5, the DC voltage converted by the rectifier circuit section 4 is smoothed by the smoothing reactor 13 and smoothing capacitor 14. This stabilizes the output voltage output from the output terminal 7.

In the power conversion device 1 shown in Figure 1, the transformer 11 and smoothing reactor 13 are coil devices that generate a relatively high amount of heat. The heat generated in the transformer 11 and smoothing reactor 13 must be dissipated to lower the temperatures of the transformer 11 and smoothing reactor 13 to an allowable temperature or lower, for example, below approximately 100°C to 120°C. In each embodiment, a specific structure for dissipating heat from a coil device composed of a coil unit will be described.

Embodiment 1.
In the first embodiment, a first example of a transformer as a coil device will be described. As shown in Figures 2, 3, and 4, a coil device 20 is composed of one coil unit 18. A transformer 11 as the coil device 20 is formed by a core 21 having a loop-shaped magnetic path, and a first winding portion 29 (primary winding portion 11a) and a second winding portion 30 (secondary winding portion 11b) wound around the core 21.

The first winding portion 29 includes a first coil pattern 37a and a first wiring body 45a. The second winding portion 30 includes a second coil pattern 37b and a second wiring body 45b. The first coil pattern 37a and the second coil pattern 37b are formed on a metal base substrate 31. The first wiring body 45a and the second wiring body 45b are formed on a wiring member 41. The first winding portion 29 and the second winding portion 30 are electrically insulated. The metal base substrate 31 is placed on a first cooling body 39a as a cooling body 39.

The structure of the coil device 20 will be described in detail. The transformer 11 includes a metal base substrate 31, wiring member 41, core 21, and first cooling body 39a. First, core 21 is composed of an E-shaped core 23 and an I-shaped core 25. E-shaped core 23 has legs 23a, 23b, and 23c. When I-shaped core 25 abuts against legs 23a, 23b, and 23c, core 21 is formed with a loop-shaped magnetic path. E-shaped core 23 and I-shaped core 25 are fixed together with an adhesive (not shown).

The core 21 (E-type core 23 and I-type core 25) is, for example, a ferrite core such as a manganese-zinc (Mn-Zn) ferrite core or a nickel-zinc (Ni-Zn) ferrite core. An amorphous core or an iron dust core may also be used as the core 21.

Note that while the core 21 is constructed by combining an E-shaped core 23 and an I-shaped core 25, the combination is not limited to the E-shaped core 23 and the I-shaped core 25, as long as the combination can form a core 21 with a loop-shaped magnetic path. For example, it may be a core made up of two U-shaped cores. It may also be a core made up of two E-shaped cores. It may also be a core made up of a T-shaped core and a U-shaped core.

The metal base substrate 31 is composed of a metal base body 34, an insulating layer 35, and a coil pattern 37. In the metal base substrate 31, the coil pattern 37 is disposed on the metal base body 34 with the insulating layer 35 interposed therebetween. The metal base body 34 has a thermal conductivity of 1.0 W/(m·K) or more, preferably 10.0 W/(m·K) or more, and more preferably 100.0 W/(m·K) or more. The metal base body 34 is formed from a metal material such as copper, iron, aluminum, an iron alloy, or an aluminum alloy.

The metal base substrate 31 comprises a first metal base substrate 31a and a second metal base substrate 31b. The first metal base substrate 31a includes a first extension portion 33a extending from the outer region of the core 21 to the inner region of the core 21. The second metal base substrate 31b includes a second extension portion 33b extending from the outer region of the core 21 to the inner region of the core 21.

The first metal base substrate 31a and the second metal base substrate 31b are arranged such that the first extension portion 33a and the second extension portion 33b face each other, with an insertion portion 32 formed between the first metal base substrate 31a and the second metal base substrate 31b, through which the legs 23a to 23c of the core 21 are inserted. The insertion portion 32 includes an insertion portion 32a through which the leg 23a is inserted, an insertion portion 32b through which the leg 23b is inserted, and an insertion portion 32c through which the leg 23c is inserted.

The metal base substrate 31 has a slit portion 27 formed therein that prevents loop-shaped induced current from flowing in the area surrounding the core 21. The slit portion 27 is formed in the inner region of the core 21. The slit portion 27 is formed in a manner that connects to the insertion portion 32. The first extension portion 33a (first metal base substrate 31a) and the second extension portion 33b (second metal base substrate 31b) are arranged with a length SL corresponding to the slit portion 27 between them.

The slit portion 27 physically and electrically separates the portions of the first metal base substrate 31a and the second metal base substrate 31b that surround the leg portion 23a. The slit portion 27 functions to prevent the formation of a short coil in the metal base body 34. This will be described later.

The insulating layer 35 has a first main surface 35a and a second main surface 35b. The second main surface 35b is in contact with almost the entire surface of the metal base body 33. The insulating layer 35 is electrically insulating. The insulating layer 35 is formed, for example, from epoxy resin, glass fiber reinforced epoxy resin, polyimide resin, or the like. Furthermore, a thermally conductive filler may be mixed into the epoxy resin, etc., to improve thermal conductivity.

It is preferable to make the thickness of the insulating layer 35 as thin as possible without affecting electrical insulation or manufacturability. The thickness of the insulating layer 35 is set, for example, to a thickness of approximately 1 μm or more and 2000 μm or less. More preferably, the thickness of the insulating layer 35 is set to a thickness of approximately 1 μm or more and 200 μm or less. The insulating layer 35 is formed with an insertion portion 32a through which the leg 23a of the E-shaped core 23 is inserted, an insertion portion 32b through which the leg 23b is inserted, and an insertion portion 32c through which the leg 23c is inserted.

A coil pattern 37 is formed on the first main surface 35a of the insulating layer 35. The coil pattern 37 includes a first coil pattern 37a and a second coil pattern 37b. The first coil pattern 37a is formed on the first metal base substrate 31a. The second coil pattern 37b is formed on the second metal base substrate 31b.

The first coil pattern 37a includes a first coil pattern first portion 37af and a first coil pattern second portion 37as. The inverter circuit portion 2 is formed on the first metal base substrate 31a. The first coil pattern first portion 37af and the first coil pattern second portion 37as are electrically connected to the inverter circuit portion 2. Note that wiring patterns (not shown) other than the first coil pattern 37a may also be formed on the first metal base substrate 31a.

The second coil pattern 37b includes a second coil pattern first portion 37bf and a second coil pattern second portion 37bs. The rectifier circuit portion 4 is formed on the second metal base substrate 31b. The second coil pattern first portion 37bf and the second coil pattern second portion 37bs are electrically connected to the rectifier circuit portion 4. Note that wiring patterns (not shown) other than the second coil pattern 37b may also be formed on the second metal base substrate 31b.

The first metal base substrate 31a, on which the first coil pattern 37a and the inverter circuit section 2 are formed, has an electrical primary potential. The second metal base substrate 31b, on which the second coil pattern 37b and the rectifier circuit section 4 are formed, has an electrical secondary potential. The first metal base substrate 31a, which has a primary potential, and the second metal base substrate 31b, which has a secondary potential, are electrically insulated from each other.

The thickness of the first coil pattern 37a and the second coil pattern 37b (coil pattern 37) is, for example, approximately 1 μm or more and 2000 μm or less. The first coil pattern 37a and the second coil pattern 37b are formed from, for example, copper, nickel, gold, aluminum, silver, or tin. The coil pattern 37 may also be formed from an alloy containing these metals.

Heat generated in the coil pattern 37 is dissipated to the metal base body 34 via the insulating layer 35, which is in contact with almost the entire surface of the metal base body 34. By making the thickness of the insulating layer 35 as thin as possible without affecting both electrical insulation and manufacturability, the heat dissipation performance of the heat dissipation path can be improved.

The first coil pattern 37a and the metal base body 34 are separated by a creepage distance CR1. When the potential of the first coil pattern 37a and the potential of the metal base body 34 differ, ensuring the creepage distance CR1 can prevent dielectric breakdown from occurring on the creepage between the first coil pattern 37a and the metal base body 34.

The creepage distance CR1 is set based on the potential difference between the potential of the first coil pattern 37a and the potential of the metal base main body 34. The greater the potential difference, the longer the creepage distance CR1 needs to be set. From the perspective of preventing insulation breakdown, it is preferable to arrange the first coil pattern 37a in a rounded pattern to avoid sharp corners, etc. In addition, the second coil pattern 37b and the metal base main body 34 are separated by a creepage distance CR2. The creepage distance CR2 is also set in the same way as the creepage distance CR1.

The wiring member 41 is arranged to straddle the first metal base substrate 31a and the second metal base substrate 31b, which face each other across the slit portion 27. The wiring member 41 includes an insulating portion 43 and a wiring main body 45. The wiring member 41 is formed with insertion portions 42. The insertion portions 42 include insertion portion 42a through which leg portion 23a of the E-shaped core 23 is inserted, insertion portion 42b through which leg portion 23b is inserted, and insertion portion 42c through which leg portion 23c is inserted. A printed wiring board is used as the wiring member 41. In addition to a printed circuit board, the wiring member 41 may also be, for example, a metal bus bar covered with an insulating coating.

The insulating portion 43 has a first main surface 43a and a second main surface 43b. The wiring body 45 includes a first wiring body 45a and a second wiring body 45b. The first wiring body 45a and the second wiring body 45b are formed from, for example, copper, nickel, gold, aluminum, silver, or tin. The first wiring body 45a is formed on the first main surface 43a of the insulating portion 43. The first wiring body 45a is arranged to surround the insertion portion 42a. The second wiring body 45b is formed on the second main surface 43b of the insulating portion 43. The second wiring body 45b is arranged to surround the insertion portion 42a.

One end of the first wiring body 45a is electrically connected to the first coil pattern first portion 37af via the through-hole conductive portion 47 and the conductive bonding member 53. The other end of the first wiring body 45a is electrically connected to the first coil pattern second portion 37as via the through-hole conductive portion 47 and the conductive bonding member 53. One end of the second wiring body 45b is electrically connected to the second coil pattern first portion 37bf via the conductive bonding member 53. The other end of the second wiring body 45b is electrically connected to the second coil pattern second portion 37bs via the conductive bonding member 53.

The joining member 53 may be, for example, a conductive adhesive or solder. The first wiring body 45a is thermally joined to the first metal base substrate 31a via the joining member 53 so as to be thermally conductive. The second wiring body 45b is thermally joined to the second metal base substrate 31b via the joining member 53 so as to be thermally conductive.

A thermally conductive member (not shown) may also be interposed between the wiring body 45 and the coil pattern 37. The wiring body 45 and the coil pattern 37 are thermally bonded to each other via the thermally conductive member in addition to the bonding member 53, allowing for thermal conductivity. The thermal conductivity of the thermally conductive member is preferably 0.1 W/(m·K) or more, more preferably 1.0 W/(m·K) or more, and even more preferably 10.0 W/(m·K) or more. Examples of the thermally conductive member that can be used include thermally conductive grease, a thermally conductive sheet, and a thermally conductive adhesive.

The insulating portion 43 has electrical insulating properties. The insulating portion 43 is formed, for example, from glass fiber reinforced epoxy resin, phenolic resin, polyphenylene sulfide (PPS), or polyether ether ketone (PEEK).

As such, the printed circuit board used as wiring member 41 may generally be formed from a material that is considered to have a relatively low thermal conductivity. In other words, the printed circuit board used as wiring member 41 may be a general-purpose printed circuit board. Furthermore, a ceramic substrate such as aluminum oxide, aluminum nitride, or silicon carbide may also be used as the printed circuit board used as wiring member 41. Furthermore, conductive portions (not shown) may be formed on the surface or inside of wiring member 41.

The wiring member 41 may also be a laminated bus bar, formed by laminating an insulating film sheet and a metal conductor. The insulating film sheet may be, for example, a film made from polyethylene terephthalate (PET), a film made from polyimide (PI), or paper made from aramid (fully aromatic polyamide) fibers. The insulating film sheet may be adhered to the metal conductor, which forms the wiring body, by an adhesive or pressure-sensitive adhesive layer.

The metal base substrate 31, on which the coil pattern 37 and other components are formed, is placed on the first cooling body 39a. The metal base substrate 31 is fixed to the first cooling body 39a, for example, with screws (not shown). A groove 40 is formed in the main surface 39aa of the first cooling body 39a to accommodate the E-shaped core 23. The thermal conductivity of the first cooling body 39a is preferably 1.0 W/(m·K) or greater, more preferably 10.0 W/(m·K) or greater, and even more preferably 100.0 W/(m·K) or greater.

The first cooling body 39a is formed from a metal material such as copper, iron, aluminum, an iron alloy, or an aluminum alloy. The first cooling body 39a may also be formed from a resin with high thermal conductivity. The first cooling body 39a may be electrically connected to another member so that it has the same potential as the ground potential.

The metal base substrate 31 abuts against the main surface 39aa of the first cooling body 39a, so that the first cooling body 39a and the metal base substrate 31 are thermally coupled to each other so that heat can be conducted between them. By interposing a thermally conductive member (not shown) between the main surface 39aa of the first cooling body 39a and the metal base substrate 31, heat conduction becomes even easier.

In addition, the E-shaped core 23 abuts against the bottom surface of the groove 40 of the first cooling body 39a, so that the core 21 (E-shaped core 23) and the first cooling body 39a are thermally coupled to enable thermal conduction. By interposing a thermally conductive member (not shown) between the bottom surface of the groove 40 and the E-shaped core 23, heat conduction becomes even easier.

The E-shaped core 23 and the first cooling body 39a may be bonded together with an adhesive (not shown) or the like. The first cooling body 39a may also form part of the housing of the coil device 20. The first cooling body 39a may also form part of the housing of the power conversion device 1 that includes the coil device 20. Furthermore, a surface of the first cooling body 39a other than the surface on which the metal base substrate 31 is arranged may be air-cooled or water-cooled. The coil device 20 (power conversion device 1) according to embodiment 1 is configured as described above.

Next, we will briefly explain the operation of the above-mentioned power conversion device (coil device 20, transformer 11). First, we mentioned that the slit portion 27 in the coil device 20 (transformer 11) has the function of preventing the formation of a short coil in the metal base body 34. This will be explained below.

As shown in the left diagram in Figure 5, if no slits are provided in the metal base body 34, the portion of the metal base body 34 that surrounds the leg portion 23a around which the coil pattern 37 is wound will be physically and electrically connected. Therefore, when a current flows between terminals TA and TB in the coil pattern 37, an induced current RP will flow in a loop in that portion of the metal base body 34.

As shown in the right diagram in Figure 5, the induced current RP becomes a short coil magnetically coupled to the coil pattern 37 in the metal base body 34. As a result, the coil device 20 (transformer 11) is unable to exhibit the desired performance. Therefore, by providing a slit portion 27 in the metal base body 34, the flow of the induced current RP is blocked, allowing the transformer 11 to exhibit the desired performance.

In a power conversion device 1 equipped with a coil device 20 (transformer 11), the AC voltage converted in the inverter circuit unit 2 is converted to an arbitrary voltage by the transformer 11. At this time, as shown in FIG. 6, the AC voltage converted by the inverter circuit unit 2 flows through a current path PT1. The current path PT1 is the first winding unit 29, which includes the first coil pattern 37a and the first wiring body 45a. The first winding unit 29 becomes the primary winding unit 11a of the transformer 11.

The AC voltage converted to an arbitrary voltage by the transformer 11 flows through current path PT2. Current path PT2 is the second winding section 30, which includes the second coil pattern 37b and the second wiring main body 45b. The second winding section 30 becomes the secondary winding section 11b of the transformer 11. The AC voltage that flows through current path PT2 is converted to DC voltage in the rectifier circuit section 4. During this operation, in the coil device 20 (transformer 11), the AC voltage flows through the primary winding section 11a, causing the primary winding section 11a to generate heat. Furthermore, the AC voltage flows through the secondary winding section 11b, causing the secondary winding section 11b to generate heat.

In the coil device 20 described above, heat generated in the portion of the first winding portion 29 located in the outer region of the core 21 is dissipated to the first cooling body 39a via the insulating layer 35 and the metal base body 34. Heat generated in the portion of the first winding portion 29 located in the inner region of the core 21 is also dissipated to the first cooling body 39a via the insulating layer 35 and the metal base body 34.

This allows the heat generated in the part of the first winding portion 29 located in the inner region of the core 21 to be dissipated to the first cooling body 39a to the same extent as the heat generated in the part of the first winding portion 29 located in the outer region of the core 21.

Furthermore, with regard to the secondary winding portion 11b, similar to the primary winding portion 11a, heat generated in the portion of the secondary winding portion 11b located in the outer region of the core 21 is dissipated to the first cooling body 39a via the insulating layer 35 and the metal base body 34. Heat generated in the portion of the secondary winding portion 11b located in the inner region of the core 21 is also dissipated to the first cooling body 39a via the insulating layer 35 and the metal base body 34.

This allows heat generated in the portion of the secondary winding portion 11b located in the inner region of the core 21 to be dissipated to the first cooling body 39a to the same extent as heat generated in the portion of the secondary winding portion 11b located in the outer region of the core 21. As a result, the heat dissipation performance of the coil device 20 can be improved. Furthermore, there is no need to increase the size of the first coil pattern 37a and the second coil pattern 37b, etc., for heat dissipation, which contributes to the miniaturization of the coil device 20 and, ultimately, the power conversion device 1.

In addition, in the coil device 20 described above, the metal base substrate 31 comprises a first metal base substrate 31a and a second metal base substrate 31b. The first metal base substrate 31a and the second metal base substrate 31b are not an integrated metal base substrate, but are separate metal base substrates. Therefore, the area per metal base substrate can be reduced compared to when the first metal base substrate 31a and the second metal base substrate 31b are formed from a single integrated metal base substrate.

This reduces the warping of the metal base substrate 31 that is expected to occur when manufacturing the coil device 20. It also optimizes the number of metal base bodies that can be removed from a sheet-shaped metal base body. As a result, this contributes to reducing the manufacturing costs of the metal base substrate.

Furthermore, by making the first metal base substrate 31a and the second metal base substrate 31b separate metal base substrates, it is possible to standardize the metal base substrate 31 even when the input voltage to the input terminal 6 of the power conversion device 1 is different. This will be explained below.

First, if the magnetic flux density of the core 21 (leg 23a) shown in Figure 2 is Bm, the period during which the switching element 9 of the inverter circuit section 2 is on is Ton, the input voltage to the input terminal 6 is Vin, the number of turns of the first winding section 29 (primary winding section 11a) in the coil device 20 (transformer 11) is N, and the cross-sectional area of the leg 23a in the core 21 (E-shaped core 23) is Ae, then the following relationship holds: Vin x Ton = Bm x N x Ae.

Here, magnetic flux density Bm affects the heat generation of core 21. Therefore, when input voltage Vin increases, if the heat dissipation structure of core 21 is the same, it is preferable that magnetic flux density Bm also be approximately the same. Let's assume that the input voltage Vin input to input terminal 6 of power conversion device 1 increases, for example, three times.

In this case, based on the above equation, it is necessary to select one of the following values: the period Ton during which the switching element 9 is on is multiplied by one-third, the number of turns N of the first winding portion 29 is multiplied by three, or the cross-sectional area Ae of the leg portion 23a is multiplied by three. Furthermore, it is necessary to satisfy the above equation by combining increases and decreases in the values of the period Ton, the number of turns N, and the cross-sectional area Ae.

In addition, if the period Ton during which the switching element 9 is on is reduced, the amount of heat generated by both the switching element 9 in the inverter circuit section 2 and the rectifier element 12 in the rectifier circuit section 4 will increase. Therefore, if the heat dissipation structure of the switching element 9 and the heat dissipation structure of the rectifier element 12 are equivalent, it is preferable that the period Ton during which the switching element 9 is on is also equivalent.

When increasing the number of turns N of the first winding portion 29 (primary winding portion 11a) in the wiring member 41, it is not necessary to change the first metal base substrate 31a and the second metal base substrate 31b as the metal base substrate 31; it is sufficient to change the wiring member 41. In this case, the metal base substrate 31 may be formed from a single metal base substrate.

To increase the cross-sectional area Ae of the leg 23a, the first metal base substrate 31a and the second metal base substrate 31b need only be modified to ensure the spacing (length SL) between them so that the insertion portion 32a (32) through which the leg 23a of the E-shaped core 23 is inserted is formed, without modifying the first metal base substrate 31a or the second metal base substrate 31b. Furthermore, the wiring member 41 can be modified so that the insertion portion 42a (42) through which the leg 23a of the E-shaped core 23 is inserted is formed in the wiring member 41.

The number of turns N of the first winding portion 29 (primary winding portion 11a) in the wiring member 41 has a limited design range due to constraints on the insulation distance and wiring width. Therefore, by using the first metal base substrate 31a and the second metal base substrate 31b as the metal base substrate 31, the cross-sectional area Ae of the leg portion 23a of the E-shaped core 23 can be changed, and the design range can be expanded by combining the number of turns N and the cross-sectional area Ae.

Figure 7 shows an example of the structure of the power conversion device 1 (coil device 20) when it is assumed that the input voltage Vin input to the input terminal 6 of the power conversion device 1 is tripled. In the power conversion device 1 shown in Figure 7, a first metal base substrate 31a and a second metal base substrate 31b are used as the metal base substrate 31, and the insertion portion 42 of the wiring member 41 and the cross-sectional area Ae of the E-shaped core 23 are changed.

In the power conversion device 1 shown in Figure 7, the cross-sectional area Ae (3 CD x CW) of the E-shaped core 23 is three times larger than that of the power conversion device 1 shown in Figure 2. The first metal base substrate 31a and the second metal base substrate 31b are arranged a length SL apart, forming an insertion portion 32 through which the E-shaped core 23, whose cross-sectional area Ae has been increased three times, can be inserted. In addition, the area of the insertion portion 42 of the wiring member 41 is increased three times. When the input voltage Vin increases three times, the cross-sectional area Ae has been increased three times, and therefore the above relationship holds.

In this way, when changing the electrical specifications of the power conversion device 1, such as increasing the input voltage Vin, the dimensions of the wiring member 41 can be changed while the dimensions of the first metal base substrate 31a and the second metal base substrate 31b remain unchanged, allowing the first metal base substrate 31a and the second metal base substrate 31b to be used before the change. This allows the first metal base substrate 31a and the second metal base substrate 31b to be standardized even when the electrical specifications are changed. As a result, this can contribute to reducing the manufacturing cost of the metal base substrate 31.

In the above-described power conversion device 1, the first wiring body 45a of the first winding portion 29 is arranged on the first main surface 43a of the insulating portion 43 of the wiring member 41, and the second wiring body 45b of the second winding portion 30 is arranged on the second main surface 43b of the insulating portion 43. For example, if the voltage of the first winding portion 29 is higher than the voltage of the second winding portion 30, the current flowing through the second winding portion 30 will be greater than the current flowing through the first winding portion 29, and the amount of heat generated by the second winding portion 30 will be greater than the amount of heat generated by the first winding portion 29.

For this reason, it is preferable to arrange the second winding portion 30 on the second main surface 43b of the insulating portion 43, which is closer to the second metal base substrate 31b, and to arrange the first winding portion 29, which has a relatively high voltage, on the first main surface 43a of the insulating portion 43 in order to more reliably provide electrical insulation.

Furthermore, in the coil device 20 of the above-described power conversion device 1, the first winding portion 29 and the second winding portion 30 are each wound once around the leg portion 23a of the E-shaped core 23 (number of turns: 1). Furthermore, a single printed circuit board was used as an example of the wiring member 41 on which the first wiring body 45a and the second wiring body 45b are arranged.

The number of turns of each of the first winding portion 29 and the second winding portion 30 may be two or more, depending on the specifications. To increase the number of turns, two or more printed circuit boards may be stacked as the wiring member 41. When two or more printed circuit boards are stacked, one printed circuit board may be electrically connected to the other printed circuit boards using a conductive joining member. Also, for example, a multilayer printed circuit board may be applied in which wiring bodies and insulating portions are alternately stacked.

In this way, when increasing the number of turns of each of the first winding section 29 and the second winding section 30, it is sufficient to stack the printed circuit boards, and there is no need to increase the size of the first metal base substrate 31a and the second metal base substrate 31b. As a result, this contributes to the miniaturization of the coil device 20 and, ultimately, the power conversion device 1.

(First Modification)
A coil device 20 (power conversion device 1) according to a first modification will be described. As shown in Fig. 8, in the coil device 20, a sealing member 55 is filled between the metal base substrate 31 and the wiring member 41. In addition, a sealing member 55 is filled between the core 21 (E-shaped core 23) and the first cooling body 39a (groove portion 40). Note that the rest of the configuration is the same as that of the coil device 20 shown in Fig. 4, so the same members are given the same reference numerals and their description will not be repeated unless necessary.

The sealing member 55 is preferably formed from a material with a thermal conductivity of approximately 0.1 W/(m·K) or more, preferably approximately 1.0 W/(m·K). The sealing member 55 is electrically insulating. The sealing member 55 may have a Young's modulus of 1 MPa or more. The sealing member 55 may be formed from an elastic resin material. The sealing member 55 may be formed from an epoxy resin containing a thermally conductive filler. The sealing member 55 may be formed from a rubber material such as silicone or urethane.

By filling the space with such a sealing member 55, heat generated in the metal base substrate 31 and the wiring member 41 can be dissipated to the first cooling body 39a via the sealing member 55. As a result, there is no need to increase the size of the metal base substrate 31, etc., in order to dissipate heat from the metal base substrate 31 and the wiring member 41, which further contributes to the miniaturization of the coil device 20 and, ultimately, the power conversion device 1.

In addition, between conductive materials with different potentials, it is generally required to maintain a certain creepage distance between one conductive material and the other to prevent dielectric breakdown. If it is anticipated that the creepage between one conductive material and the other may be contaminated by electrically conductive substances, a longer creepage distance must be maintained.

In the coil device 20 according to the first modified example described above, a sealing member 55 is filled between the metal base substrate 31 and the wiring member 41, including between the first metal base substrate 31a and the second metal base substrate 31b. This prevents the surface of the metal base substrate 31 from being contaminated by electrically conductive substances. As a result, it is possible to reduce both the creepage distance between the first coil pattern 37a and the metal base main body 34 and the creepage distance between the second coil pattern 37b and the metal base main body 34, thereby contributing to the miniaturization of the coil device 20 and, ultimately, the power conversion device 1.

In addition, with the E-shaped core 23 housed in the groove 40 provided in the first cooling body 39a, a sealing member 55 is filled between the groove 40 and the E-shaped core 23. This allows heat generated in the core 21 to be dissipated to the first cooling body 39a via the sealing member 55. As a result, there is no need to increase the size of the core 21 for heat dissipation, which further contributes to the miniaturization of the coil device 20 and, ultimately, the power conversion device 1.

Furthermore, the sealing member 55 fixes the wiring member 41 to the metal base substrate 31, and fixes the core 21 (E-shaped core 23) to the first cooling body 39a. As a result, the vibration resistance of the coil device 20, and ultimately the vibration resistance of the power conversion device 1, can be improved.

(Second Modification)
A coil device 20 (power conversion device 1) according to a second modification will now be described. As shown in Fig. 9, in the coil device 20, an elastic member 57 such as a spring serving as a biasing member is interposed between the metal base substrate 31 and the E-shaped core 23. Note that the rest of the configuration is similar to that of the coil device 20 shown in Fig. 4, and therefore the same members are designated by the same reference numerals, and their description will not be repeated unless necessary.

In the coil device 20 according to the second modified example described above, an elastic member 57 is interposed between the metal base substrate 31 and the E-shaped core 23. This allows heat generated in the E-shaped core 23 (core 21) to be efficiently conducted to the metal base substrate 31 (first metal base substrate 31a and second metal base substrate 31b) via the elastic member 57, such as a spring, and the heat conducted to the metal base substrate 31 (metal base main body 34) is dissipated to the first cooling body 39a. As a result, there is no need to increase the size of the core 21 for heat dissipation, which further contributes to the miniaturization of the coil device 20 and, ultimately, the power conversion device 1.

In addition, the elastic member 57 interposed between the metal base substrate 31 and the E-shaped core 23 biases the E-shaped core 23 (core 21) against the first cooling body 39a. As a result, the vibration resistance of the coil device 20, and ultimately the vibration resistance of the power conversion device 1, can be improved.

(Third Modification)
A coil device 20 (power conversion device 1) according to a third modified example will now be described. As shown in Fig. 10, in the coil device 20, a metal base substrate 31 is formed with an uneven portion 59 as a biasing member. The uneven portion 59 is interposed between the metal base substrate 31 and the E-shaped core 23. Burrs generated during processing of the metal base substrate 31 are used as the uneven portion 59. Pressing is an example of processing the outer shape of the metal base substrate 31 (metal base main body 34).

In press working, the metal base substrate 31 (metal base main body 34) is processed by applying pressure to the metal base substrate 31 using a mold. During this press working, burrs are generated on the metal base main body 34. The burrs are generated so that they protrude from the surface of the metal base substrate 31. For example, the burrs are generated as alternating convex and concave portions.

In this coil device 20, burrs generated by press processing are interposed between the metal base substrate 31 and the E-shaped core 23 (core 21) as uneven portions 59. The rest of the configuration is the same as that of the coil device 20 shown in Figure 4, so the same components are given the same reference numerals and their descriptions will not be repeated unless necessary.

In the coil device 20 according to the third modified example described above, burrs generated on the metal base substrate 31 during press working are formed as uneven portions 59 and are interposed between the metal base substrate 31 and the E-shaped core 23. As a result, the uneven portions 59 interposed between the metal base substrate 31 and the E-shaped core 23 urge the E-shaped core 23 (core 21) toward the first cooling body 39a.

In addition, the convex portions of the uneven portion 59 acting as burrs have a pointed shape. This restricts the movement of the E-shaped core 23 (21) in a direction intersecting the direction that urges the E-shaped core 23 (core 21) toward the first cooling body 39a. As a result, the vibration resistance of the coil device 20, and ultimately the vibration resistance of the power conversion device 1, can be further improved.

In addition, the uneven portion 59 biases the E-shaped core 23 (core 21) toward the first cooling body 39a, allowing the heat generated in the core 21 to be efficiently dissipated to the first cooling body 39a. As a result, there is no need to enlarge the core 21 for heat dissipation, which further contributes to the miniaturization of the coil device 20 and, ultimately, the power conversion device 1.

Embodiment 2.
In the second embodiment, a second example of a transformer as a coil device will be described. As shown in Fig. 11, a metal base substrate 31 is formed with stepped portions 61a and 61b as sandwiching portions for sandwiching an E-shaped core 23 (core 21).

The first extension portion 33a of the first metal base substrate 31a and the second extension portion 33b of the second metal base substrate 31b face each other across the slit portion 27. The step portion 61a is formed on the first extension portion 33a of the opposing first extension portion 33a and second extension portion 33b. The step portion 61b is formed on the second extension portion 33b of the opposing first extension portion 33a and second extension portion 33b.

One end of the E-shaped core 23 is received in the stepped portion 61a, and the other end of the E-shaped core 23 is received in the stepped portion 61b, so that the E-shaped core 23 is sandwiched between the stepped portion 61a (first extension portion 33a) and the stepped portion 61b (second extension portion 33b) and is biased against the first cooling body 39a. The rest of the configuration is the same as that of the coil device 20 shown in Figure 4, so the same components are designated by the same reference numerals and their descriptions will not be repeated unless necessary.

In the coil device 20 described above, the E-shaped core 23 is sandwiched between the step portion 61a in the first extension portion 33a and the step portion 61b in the second extension portion 33b, and is biased against the first cooling body 39a. This restricts the movement of the E-shaped core 23. As a result, the vibration resistance of the coil device 20, and ultimately the vibration resistance of the power conversion device 1, can be improved.

In addition, since the E-shaped core 23 is received in the step portion 61a, the contact area between the E-shaped core 23 and the first metal base substrate 31a (first extension portion 33a) increases. Since the E-shaped core 23 is received in the step portion 61b, the contact area between the E-shaped core 23 and the second metal base substrate 31b (second extension portion 33b) increases.

As a result, heat generated in the E-shaped core 23 (core 21) is efficiently conducted to the metal base substrate 31 (first metal base substrate 31a and second metal base substrate 31b), and the heat conducted to the metal base substrate 31 (metal base main body 34) is dissipated to the first cooling body 39a. As a result, there is no need to enlarge the core 21 for heat dissipation, which further contributes to the miniaturization of the coil device 20 and, ultimately, the power conversion device 1.

(First Modification)
A coil device 20 (power conversion device 1) according to a first modified example will be described. As shown in Fig. 12, a first extending portion 33a of a first metal base substrate 31a has an upwardly curved portion 63a that curves upward from the E-shaped core 23 toward the wiring member 41. A second extending portion 33b of a second metal base substrate 31b has an upwardly curved portion 63b that curves upward from the E-shaped core 23 toward the wiring member 41.

The thickness of the E-shaped core 23 is set to a thickness equal to or greater than the depth of the groove 40, and the upwardly curved portions 63a and 63b are configured to abut against the E-shaped core 23. The rest of the configuration is similar to that of the coil device 20 shown in Figure 4, so the same components are given the same reference numerals and their descriptions will not be repeated unless necessary.

In the coil device 20 according to the first modified example described above, the E-shaped core 23 is sandwiched between the first metal base substrate 31a (upwardly curved portion 63a) and the first cooling body 39a, and the E-shaped core 23 is sandwiched between the second metal base substrate 31b (upwardly curved portion 63b) and the first cooling body 39a. The upwardly curved portions 63a and 63b urge the E-shaped core 23 toward the first cooling body 39a, securing the E-shaped core 23 (core 21) to the first cooling body 39a. This eliminates the need for a fixing member to secure the E-shaped core 23 (core 21) to the first cooling body 39a, contributing to reduced manufacturing costs.

In addition, the upward cambered portions 63a and 63b bias the E-shaped core 23 toward the first cooling body 39a, thereby improving the vibration resistance of the coil device 20 and, ultimately, the vibration resistance of the power conversion device 1. Furthermore, the upward cambered portions 63a and 63b bias the E-shaped core 23 toward the first cooling body 39a, thereby enabling heat generated in the E-shaped core 23 (core 21) to be efficiently dissipated to the first cooling body 39a.

13, an inclined portion 24 may be provided along the cambered portion 63a and the cambered portion 63b at the portion of the E-shaped core 23 where the cambered portion 63a and the cambered portion 63b contact each other. By providing the inclined portion 24 on the E-shaped core 23, the contact area between the E-shaped core 23 and each of the first metal base substrate 31a and the second metal base substrate 31b can be increased.

This allows the heat generated in the E-shaped core 23 (core 21) to be efficiently conducted to the metal base substrate 31, and the heat conducted to the metal base substrate 31 to be dissipated to the first cooling body 39a. As a result, there is no need to enlarge the core 21 for heat dissipation, which further contributes to the miniaturization of the coil device 20 and, ultimately, the power conversion device 1.

(Second Modification)
A coil device 20 (power conversion device 1) according to a second modification will be described. As shown in Fig. 14, a downwardly curved portion 65a that curves downward from the first cooling body 39a toward the E-core 23 is formed on the first extension portion 33a of the first metal base substrate 31a. A downwardly curved portion 65b that curves downward from the first cooling body 39a toward the E-core 23 is formed on the second extension portion 33b of the second metal base substrate 31b.

The thickness of the E-shaped core 23 is set to a thickness equal to or less than the depth of the groove 40, and the downwardly curved portions 65a and 65b are configured to abut against the E-shaped core 23. Other than this, the configuration is the same as that of the coil device 20 shown in Figure 4, so the same components are given the same reference numerals and their descriptions will not be repeated unless necessary.

In the coil device 20 according to the second modified example described above, the E-shaped core 23 is sandwiched between the first metal base substrate 31a (the downwardly curved portion 65a) and the first cooling body 39a, and the E-shaped core 23 is sandwiched between the second metal base substrate 31b (the downwardly curved portion 65b) and the first cooling body 39a. The downwardly curved portions 65a and 65b urge the E-shaped core 23 toward the first cooling body 39a, securing the E-shaped core 23 (core 21) to the first cooling body 39a. This eliminates the need for a fixing member to secure the E-shaped core 23 (core 21) to the first cooling body 39a, contributing to reduced manufacturing costs.

In addition, the downwardly curved portions 65a and 65b bias the E-shaped core 23 toward the first cooling body 39a, thereby improving the vibration resistance of the coil device 20 and, ultimately, the vibration resistance of the power conversion device 1. Furthermore, the downwardly curved portions 65a and 65b bias the E-shaped core 23 toward the first cooling body 39a, thereby enabling heat generated in the E-shaped core 23 (core 21) to be efficiently dissipated to the first cooling body 39a.

15, an inclined portion 24 may be provided along the downwardly curved portion 65a and the downwardly curved portion 65b at the portion of the E-shaped core 23 where the downwardly curved portion 65a and the downwardly curved portion 65b contact each other. By providing the inclined portion 24 on the E-shaped core 23, the contact area between the E-shaped core 23 and each of the first metal base substrate 31a and the second metal base substrate 31b can be increased.

This allows the heat generated in the E-shaped core 23 (core 21) to be efficiently conducted to the metal base substrate 31, and the heat conducted to the metal base substrate 31 to be dissipated to the first cooling body 39a. As a result, there is no need to enlarge the core 21 for heat dissipation, which further contributes to the miniaturization of the coil device 20 and, ultimately, the power conversion device 1.

Embodiment 3.
In the third embodiment, a third example of a transformer as a coil device will be described. As shown in Fig. 16, a convex portion 67 protruding toward the slit portion 27 is formed on the E-shaped core 23. The convex portion 67 is sandwiched between the first extension portion 33a (first metal base substrate 31a) and the second extension portion 33b (second metal base substrate 31b). The remaining configuration is similar to that of the coil device 20 shown in Fig. 4, so the same components are designated by the same reference numerals, and their description will not be repeated unless necessary.

In the coil device 20 described above, the E-shaped core 23 has a protrusion 67 that protrudes toward the slit portion 27. This allows the core 21 (E-shaped core 23) to be pressed against the first cooling body 39a while sandwiched between the first metal base substrate 31a and the second metal base substrate 31b. This improves the vibration resistance of the coil device 20, and ultimately the vibration resistance of the power conversion device 1.

In addition, since the convex portion 67 provided on the E-shaped core 23 is sandwiched between the first metal base substrate 31a and the second metal base substrate 31b, the contact area between the E-shaped core 23 and each of the first metal base substrate 31a and the second metal base substrate 31b can be increased.

This allows the heat generated in the E-shaped core 23 (core 21) to be efficiently conducted to the metal base substrate 31, and the heat conducted to the metal base substrate 31 to be dissipated to the first cooling body 39a. As a result, there is no need to enlarge the core 21 for heat dissipation, which further contributes to the miniaturization of the coil device 20 and, ultimately, the power conversion device 1.

Embodiment 4.
In the fourth embodiment, a fourth example of a transformer as a coil device will be described. As shown in Fig. 17, a screw member 69 is attached as a first fixing member, penetrating the first extension portion 33a (first metal base substrate 31a) and the E-shaped core 23 to reach the first cooling body 39a. A screw member 69 is attached as a first fixing member, penetrating the second extension portion 33b (second metal base substrate 31b) and the E-shaped core 23 to reach the first cooling body 39a. Note that the rest of the configuration is similar to that of the coil device 20 shown in Fig. 4, so the same members are designated by the same reference numerals, and their description will not be repeated unless necessary.

In the coil device 20 described above, the first metal base substrate 31a, the second metal base substrate 31b, and the E-shaped core 23 are fixed to the first cooling body 39a by the screw members 69. This improves the vibration resistance of the coil device 20, and ultimately the vibration resistance of the power conversion device 1.

In addition, heat generated in the core 21 (E-shaped core 23) is efficiently conducted to the first metal base substrate 31a and the second metal base substrate 31b (metal base substrate 31) via the screw member 69, and the heat conducted to the metal base substrate 31 is dissipated to the first cooling body 39a. As a result, there is no need to increase the size of the core 21 for heat dissipation, which further contributes to the miniaturization of the coil device 20 and, ultimately, the power conversion device 1.

(Modification)
A coil device 20 (power conversion device) according to a modified example will be described. As shown in Fig. 18, an insulating member 71 is filled between a first metal base substrate 31a (first extension portion 33a) and a second metal base substrate 31b (second extension portion 33b). A screw member 73 is attached as a second fixing member, penetrating the insulating member 71 and the E-shaped core 23 and reaching the first cooling body 39a. The remaining configuration is similar to that of the coil device 20 shown in Fig. 4, and therefore the same members are designated by the same reference numerals, and their description will not be repeated unless necessary.

In the coil device 20 according to the modified example described above, the insulating member 71 and the E-shaped core 23 interposed between the first extension portion 33a and the second extension portion 33b are fixed to the first cooling body 39a by the screw member 73. This improves the vibration resistance of the coil device 20 and, ultimately, the vibration resistance of the power conversion device 1. Furthermore, by pressing the E-shaped core 23 against the first cooling body 39a, heat generated in the core 21 can be efficiently dissipated to the first cooling body 39a.

The insulating member 71 may be made of any electrically insulating material. This more effectively prevents dielectric breakdown in the region between the first metal base substrate 31a and the second metal base substrate 31b.

Embodiment 5.
In the fifth embodiment, a fifth example of a transformer as a coil device will be described. As shown in Fig. 19, the first extension 33a (first metal base substrate 31a) is formed so that its width gradually narrows from the outer region of the core 21 toward the inner region of the core 21. The second extension 33b (second metal base substrate 31b) is formed so that its width gradually narrows from the outer region of the core 21 toward the inner region of the core 21. Note that the rest of the configuration is similar to that of the coil device 20 shown in Fig. 4, so the same components are designated by the same reference numerals, and their description will not be repeated unless necessary.

In the coil device 20 described above, the portions (root portions) of the first extension portion 33a and the second extension portion 33b located in the outer region of the core 21 have a width WA. The tip portions (inner region of the core 21) of the first extension portion 33a and the second extension portion 33b have a width WB. In the E-shaped core 23, the distance between adjacent leg portions 23a and 23b (or leg portions 23c) is distance DL. Width WA is set wider than distance DL. Width WB is set narrower than distance DL.

As a result, one first extension portion 33a abuts against the corners 22a of both legs 23a and 23b. The other first extension portion 33a abuts against the corners 22a of both legs 23a and 23c. Furthermore, one second extension portion 33b abuts against the corners 22b of both legs 23a and 23b. The other second extension portion 33b abuts against the corners 22b of both legs 23a and 23c.

The first extension 33a abuts against the corner 22a of the E-shaped core 23, and the second extension 33b abuts against the corner 22b of the E-shaped core 23 , so that the core 21 (E-shaped core 23) is sandwiched between the first extension 33a and the second extension 33b. As a result, the vibration resistance of the coil device 20, and therefore the vibration resistance of the power conversion device 1, can be improved.

(First Modification)
A first modification will be described. As shown in Fig. 20 , the first extension portion 33a has a length EFL extending from the outer region toward the inner region of the core 21. The second extension portion 33b has a length ESL extending from the outer region toward the inner region of the core 21. The length EFL of each of the two first extension portions 33a is shorter than the length ESL of each of the two second extension portions 33b. The two second extension portions 33b, each having the length ESL, are located beyond the center portion CP (extension direction) of the core 21 in the inner region of the core 21.

In the coil device 20 according to the first variant, the two second extension portions 33b of the second metal base substrate 31b are positioned beyond the central portion CP of the core 21. As a result, heat generated near the central portion CP, where the amount of heat generated in the core 21 is the highest, is efficiently conducted to the second metal base substrate 31b via the two second extension portions 33b. The heat conducted to the second metal base substrate 31b is dissipated to the first cooling body 39a.

The two first extensions 33a of the first metal base substrate 31a may be positioned beyond the center CP of the core 21. In this case, heat generated near the center CP, where the amount of heat generated in the core 21 is the highest, is efficiently conducted to the first metal base substrate 31a via the two first extensions 33a. The heat conducted to the first metal base substrate 31a is dissipated to the first cooling body 39a.

(Second Modification)
A coil device 20 (power conversion device) according to a second modification will be described. As shown in FIG. 21 , the first extension portion 33a has a length EFL extending from the outer region toward the inner region of the core 21. The second extension portion 33b has a length ESL extending from the outer region toward the inner region of the core 21. The length EFL of one first extension portion 33a is longer than the length ESL of one second extension portion 33b. The length EFL of the other first extension portion 33a is shorter than the length ESL of the other second extension portion 33b. The one first extension portion 33a having the length EFL is located in the inner region of the core 21 beyond the center portion CP (extension direction) of the core 21. The other second extension portion 33b having the length ESL is located in the inner region of the core 21 beyond the center portion CP (extension direction) of the core 21.

In the coil device 20 according to the second modified example, one of the first extension portions 33a in the first metal base substrate 31a is positioned beyond the center CP of the core 21. Furthermore, the other of the second extension portions 33b in the second metal base substrate 31b is positioned beyond the center CP of the core 21. As a result, heat generated near the center CP of the core 21, where the amount of heat generated is the highest, is efficiently conducted to the first metal base substrate 31a via one of the first extension portions 33a, and also efficiently conducted to the second metal base substrate 31b via the other second extension portion 33b. The heat conducted to the first metal base substrate 31a and the second metal base substrate 31b is dissipated to the first cooling body 39a.

Embodiment 6.
In the sixth embodiment, a sixth example of a transformer as a coil device will be described. Here, the X-Y-Z Cartesian coordinate system will be used as needed. Furthermore, the same components as those in the coil device 20 shown in FIG. 4 and other figures will be given the same reference numerals, and their descriptions will not be repeated unless necessary.

As shown in Figures 22, 23, 24, and 25, the transformer 11 as the coil device 20 includes the first core 21a, the second core 21b, the third core 21c, and the fourth core 21d as the cores 21. The cooling bodies 39 include the first cooling body 39a, the second cooling body 39b, the third cooling body 39c, the fourth cooling body 39d, the fifth cooling body 39e, and the sixth cooling body 39f. The second cooling body 39b, the third cooling body 39c, the fourth cooling body 39d, the fifth cooling body 39e, and the sixth cooling body 39f are each placed on the first cooling body 39a. The second cooling body 39b to the sixth cooling body 39f are thermally joined to the first cooling body 39a.

The first wiring body 45a includes a first wiring body first portion 45aa and a first wiring body second portion 45ab. The first wiring body first portion 45aa and the first wiring body second portion 45ab each include a portion extending along the X-axis, which is the first direction. The second wiring body 45b includes a second wiring body first portion 45ba and a second wiring body second portion 45bb. The second wiring body first portion 45ba and the second wiring body second portion 45bb each include a portion extending along the X-axis. The first wiring body first portion 45aa and the second wiring body first portion 45ba, and the first wiring body second portion 45ab and the second wiring body second portion 45bb are arranged at a distance in the Y-axis direction, which is the second direction.

The second core 21b is arranged at a distance in the X-axis direction from the first core 21a. The third core 21c is arranged at a distance in the Y-axis direction from the first core 21a. The fourth core 21d is arranged at a distance in the X-axis direction from the third core 21c and at a distance in the Y-axis direction from the second core 21b. The four cores, first core 21a to fourth core 21d, are arranged in a matrix (2x2).

The second cooling body 39b is disposed between the first core 21a and the second core 21b. The second cooling body 39b is disposed with a gap between it and the first core 21a and the second core 21b. The third cooling body 39c is disposed between the first core 21a and the third core 21c, and also between the second core 21b and the fourth core 21d.

The fourth cooling body 39d is arranged on the opposite side of the first core 21a from the side on which the third cooling body 39c is arranged, with the first core 21a sandwiched between the fourth cooling body 39d and the third cooling body 39c. The fourth cooling body 39d is also arranged on the opposite side of the second core 21b from the side on which the third cooling body 39c is arranged, with the second core 21b sandwiched between the fourth cooling body 39d and the third cooling body 39c.

The fifth cooling body 39e is arranged on the opposite side of the third core 21c from the side on which the third cooling body 39c is arranged, with the third core 21c sandwiched between the fifth cooling body 39e and the third cooling body 39c. The fifth cooling body 39e is arranged on the opposite side of the fourth core 21d from the side on which the third cooling body 39c is arranged, with the fourth core 21d sandwiched between the fifth cooling body 39e and the third cooling body 39c. The sixth cooling body 39f is arranged between the third cooling body 39c and the fourth cooling body 39d. The sixth cooling body 39f is arranged with a gap between it and the third cooling body 39c and the fourth cooling body 39d.

The third cooling body 39c is in contact with each of the first core 21a, second core 21b, third core 21c, and fourth core 21d. The third cooling body 39c is thermally bonded to each of the first core 21a, second core 21b, third core 21c, and fourth core 21d.

The fourth cooling body 39d is in contact with each of the first core 21a and the second core 21b. The fourth cooling body 39d is thermally bonded to each of the first core 21a and the second core 21b. The fifth cooling body 39e is in contact with each of the third core 21c and the fourth core 21d. The fifth cooling body 39e is thermally bonded to each of the third core 21c and the fourth core 21d. As a result, the core 21 (first core 21a to fourth core 21d) is thermally bonded to the first cooling body 39a via each of the third cooling body 39c, the fourth cooling body 39d, and the fifth cooling body 39e.

The second cooling body 39b and the sixth cooling body 39f each include an E-type cooling body 38a as the first part of the second cooling body and an I-type cooling body 38b as the second part of the second cooling body. The E-type cooling body 38a is disposed on the first cooling body 39a. The I-type cooling body 38b is disposed opposite the E-type cooling body 38a. The E-type cooling body 38a has legs 38aa, 38ab, and 38ac. The I-type cooling body 38b is disposed in contact with each of the legs 38aa, 38ab, and 38ac.

The E-type cooling body 38a and the I-type cooling body 38b are arranged with the wiring member 41 sandwiched between them, from the side where the first cooling body 39a is arranged and the side opposite the side where the first cooling body 39a is arranged. The E-type cooling body 38a is thermally bonded to the wiring member 41 via a thermal conductive member 75. The I-type cooling body 38b is thermally bonded to the wiring member 41 via a thermal conductive member 76. As a result, the wiring member 41 is thermally bonded to the first cooling body 39a via both the second cooling body 39b and the sixth cooling body 39f.

Note that the second cooling body 39b and the sixth cooling body 39f are configured by combining the E-type cooling body 38a and the I-type cooling body 38b, but as long as the wiring member 41 can be sandwiched by combining them, the configuration is not limited to the E-type cooling body 38a and the I-type cooling body 38b. For example, a configuration combining two E-type cooling bodies may also be used.

The thermal conductivity of each of the second cooling body 39b to the sixth cooling body 39f is preferably 1.0 W/(m·K) or more, more preferably 10.0 W/(m·K) or more, and even more preferably 100.0 W/(m·K) or more. Furthermore, each of the second cooling body 39b to the sixth cooling body 39f is formed from a metal material such as copper, iron, aluminum, an iron alloy, or an aluminum alloy.

Furthermore, each of the second cooling body 39b to the sixth cooling body 39f may be formed, for example, from a resin with high thermal conductivity. Each of the second cooling body 39b to the sixth cooling body 39f may be electrically connected to another member so that it has the same potential as the ground potential.

The wiring member 41 has the following insertion portions 42: insertion portion 42a, insertion portion 42b, insertion portion 42c, insertion portion 42d, and insertion portion 42e. The legs 23c (see Figure 2) of the cores 21 (first core 21a and second core 21b), the legs 23b (see Figure 2) of the cores 21 (third core 21c and fourth core 21d), the third cooling body 39c, the legs 38ac of the E-type cooling body 38a (second cooling body 39b), and the legs 38ab of the E-type cooling body 38a (sixth cooling body 39f) are inserted through the insertion portion 42a.

The legs 23a (see Figure 2) of the core 21 (first core 21a and second core 21b) and the legs 38aa of the E-type cooling body 38a (second cooling body 39b) are inserted through the insertion portion 42b. The legs 23a (see Figure 2) of the core 21 (third core 21c and fourth core 21d) and the legs 38aa of the E-type cooling body 38a (sixth cooling body 39f) are inserted through the insertion portion 42c.

The legs 23b (see Figure 2) of the core 21 (first core 21a and second core 21b), the legs 38ab of the E-type cooling body 38a (second cooling body 39b), and the fourth cooling body 39d are inserted through the insertion portion 42d. The legs 23c (see Figure 2) of the core 21 (third core 21c and fourth core 21d), the legs 38ac of the E-type cooling body 38a (sixth cooling body 39f), and the fifth cooling body 39e are inserted through the insertion portion 42e.

The first wiring main body first portion 45aa and the second wiring main body first portion 45ba are wound around the first core 21a and the second core 21b, with the second cooling body 39b interposed between them. The first wiring main body second portion 45ab and the second wiring main body second portion 45bb are wound around the third core 21c and the fourth core 21d, with the sixth cooling body 39f interposed between them.

In the coil device 20 described above, the second cooling body 39b and the sixth cooling body 39f are each thermally joined to the wiring member 41 via the thermal conduction member 75 or the thermal conduction member 76. This allows heat generated in the wiring member 41 to be dissipated to the first cooling body 39a via the second cooling body 39b and the sixth cooling body 39f. As a result, there is no need to increase the size of the wiring member 41 for heat dissipation, which contributes to the miniaturization of the coil device 20 and, ultimately, the power conversion device 1.

The third cooling body 39c is thermally bonded to each of the first core 21a, second core 21b, third core 21c, and fourth core 21d. The fourth cooling body 39d is thermally bonded to each of the first core 21a and second core 21b. The fifth cooling body 39e is thermally bonded to each of the third core 21c and fourth core 21d.

This allows heat generated in the core 21 (first core 21a to fourth core 21d) to be efficiently conducted to the third cooling body 39c, fourth cooling body 39d, and fifth cooling body 39e, respectively, and further allows the heat conducted to the third cooling body 39c, fourth cooling body 39d, and fifth cooling body 39e to be dissipated to the first cooling body 39a. As a result, there is no need to increase the size of the core 21 for heat dissipation, which contributes to the miniaturization of the coil device 20 and, ultimately, the power conversion device 1.

In addition, in the coil device 20 described above, the core 21 is arranged with a gap between it and the second cooling body 39b and the sixth cooling body 39f, but the core 21 may be arranged so that it contacts the second cooling body 39b and the sixth cooling body 39f. That is, the first core 21a and the second core 21b may be arranged so that they contact the second cooling body 39b, and the third core 21c and the fourth core 21d may be arranged so that they contact the sixth cooling body 39f.

By bringing the core 21 into contact with each of the second cooling body 39b and the sixth cooling body 39f, heat generated in the core 21 can be conducted to each of the second cooling body 39b and the sixth cooling body 39f and dissipated to the first cooling body 39a, allowing the heat generated in the core 21 to be effectively dissipated to the first cooling body 39a. As a result, there is no need to increase the size of the core 21 for heat dissipation, which further contributes to the miniaturization of the coil device 20 and, ultimately, the power conversion device 1.

(Modification)
A coil device 20 (power conversion device 1) according to a modified example will be described. As shown in Figures 26, 27, and 28, the coil device 20 includes a lid cooling body 39g in addition to first cooling body 39a to sixth cooling body 39f as cooling bodies 39. Lid cooling body 39g is disposed so as to cover cores 21 (first core 21a to fourth core 21d) and second cooling body 39b to sixth cooling body 39f.

A heat-conducting member 77 is interposed between the lid cooling body 39g and the core 21 and the second cooling body 39b to the sixth cooling body 39f. The lid cooling body 39g is fixed to the second cooling body 39b to the sixth cooling body 39f with screw members 74. The rest of the configuration is similar to that of the coil device 20 shown in Figures 22 to 24 or 4, etc., so the same members are designated by the same reference numerals and their descriptions will not be repeated unless necessary.

The thermal conductivity of the lid cooling body 39g is preferably 1.0 W/(m·K) or more, more preferably 10.0 W/(m·K) or more, and even more preferably 100.0 W/(m·K) or more. The lid cooling body 39g is formed from a metal material such as copper, iron, aluminum, an iron alloy, or an aluminum alloy.

Furthermore, the lid cooling body 39g may be formed, for example, from a resin with high thermal conductivity. The lid cooling body 39g may be electrically connected to other components so that it has the same potential as the ground potential.

In the coil device 20 described above, a thermally conductive member 77 is interposed between the lid cooling body 39g and the core 21 and the second cooling body 39b to the sixth cooling body 39f. The lid cooling body 39g is thermally bonded to the core 21 and the second cooling body 39b to the sixth cooling body 39f via the thermally conductive member 77. The second cooling body 39b to the sixth cooling body 39f are also thermally bonded to the first cooling body 39a.

This allows heat generated in the core 21 to be conducted to the lid cooling body 39g, and the heat conducted to the lid cooling body 39g can then be dissipated to the first cooling body 39a via the second cooling body 39b to the sixth cooling body 39f. As a result, there is no need to increase the size of the core 21 for heat dissipation, which further contributes to the miniaturization of the coil device 20 and, ultimately, the power conversion device 1.

In addition, the core 21 and the second cooling body 39b to the sixth cooling body 39f, along with the lid cooling body 39g, are fixed to the first cooling body 39a by the screw member 74. This improves the vibration resistance of the coil device 20, and ultimately the vibration resistance of the power conversion device 1.

In the coil device 20 described above, the cores 21 are arranged in a matrix (2x2) of four cores 21a to 21d. The number and arrangement of the cores 21 are not limited to this.

In addition, the coil device described in each of the above-mentioned embodiments has been described as being composed of one coil unit, but the coil device can also be applied to a coil device composed of two or more coil units.

The coil device 20 (power conversion device 1) described in each embodiment can be combined in various ways as needed.

The embodiments disclosed herein are illustrative and not limiting. The scope of the present disclosure is defined by the claims, not the scope described above, and is intended to include all modifications within the meaning and scope of the claims.

The present disclosure includes the following aspects.
[Appendix 1]
A coil device having a coil unit,
The coil unit includes:
one or more cores having a looped magnetic path;
a metal base substrate disposed in an inner region of the core and an outer region of the core, the metal base substrate having a first coil pattern and a second coil pattern formed on a metal base body with an insulating layer interposed therebetween;
a first winding portion including the first coil pattern and wound around the core in a manner passing through the inner region of the core;
a second winding portion including the second coil pattern, wound around the core in a manner passing through the inner region of the core, and electrically insulated from the first winding portion;
one or more cooling bodies including a first cooling body joined to the metal base body on the side opposite to the side on which the insulating layer is formed,
The metal base substrate is
a first metal base substrate on which the first coil pattern is formed;
a second metal base substrate on which the second coil pattern is formed,
A coil device in which the first metal base substrate and the second metal base substrate are arranged facing each other, with an insertion portion through which the core is inserted formed between the first metal base substrate and the second metal base substrate.

[Appendix 2]
a slit portion that prevents a loop-shaped induced current from flowing in a portion surrounding the core is formed in the metal base substrate in a manner that the slit portion is connected to the insertion portion;
2. The coil device according to claim 1, wherein the first metal base substrate and the second metal base substrate are arranged at a distance corresponding to the slit portion.

[Appendix 3]
a wiring member including a wiring main body wound around the core,
The first coil pattern is
a first coil pattern first portion;
a first coil pattern second portion;
The second coil pattern is
a first portion of a second coil pattern;
a second coil pattern second portion;
The wiring body is
a first wiring main body electrically connecting the first coil pattern first portion and the first coil pattern second portion;
a second wiring main body electrically connecting the second coil pattern first portion and the second coil pattern second portion,
the first winding portion includes the first wiring main body,
3. The coil device according to claim 1, wherein the second winding portion includes the second wiring body.

[Appendix 4]
the wiring member is a printed circuit board,
4. The coil device according to claim 3, wherein the wiring body is disposed on the printed circuit board.

[Appendix 5]
the wiring member is located in the inner region of the core and the outer region of the core, surrounded by the core, on the opposite side of the metal base substrate from the side where the first cooling body is located,
a receiving groove portion for receiving the core is formed in the first cooling body;
5. The coil device according to claim 3, wherein a sealing material is filled between the wiring member and the metal base substrate, and between the receiving groove and the core.

[Appendix 6]
A coil device described in any one of appendices 1 to 5, wherein a biasing member is interposed between the metal base substrate and the core, biasing the portion of the core located between the metal base substrate and the first cooling body toward the first cooling body.

[Appendix 7]
the first metal base substrate includes a first extension portion extending from the outer region of the core to the inner region of the core;
the second metal base substrate includes a second extension portion extending from the outer region of the core to the inner region of the core;
A coil device described in any one of appendices 1 to 6, wherein the first metal base substrate and the second metal base substrate are arranged so that the first extension portion and the second extension portion face each other.

[Appendix 8]
A coil device as described in Appendix 7, wherein the first extension portion and the second extension portion are formed with a clamping portion that sandwiches the portion of the core located between the metal base substrate and the first cooling body between the first extension portion and the second extension portion.

[Appendix 9]
A coil device as described in Appendix 7, wherein the first extension portion and the second extension portion have a warped portion that sandwiches the portion of the core located between the metal base substrate and the first cooling body between the metal base substrate and the first cooling body and urges the core toward the first cooling body.

[Appendix 10]
A coil device as described in Appendix 7, wherein the core has a protrusion formed thereon that protrudes from a portion of the core located between the metal base substrate and the first cooling body toward the space between the first extension portion and the second extension portion.

[Appendix 11]
The core is
a first leg portion around which the first winding portion and the second winding portion are wound;
a second leg portion positioned at a first distance from the first leg portion;
the first extension portion and the second extension portion are located between the first leg portion and the second leg portion so as to face each other,
the first extension portion is formed so that its width narrows from a first width wider than the first interval to a second width narrower than the first interval toward a tip of the first extension portion,
the second extension portion is formed so that its width narrows from a third width wider than the first interval to a fourth width narrower than the first interval toward a tip of the second extension portion,
The coil device described in Appendix 7, wherein the metal base substrate is arranged to sandwich the core, with the first extension portion abutting against the first leg portion and the second leg portion, and the second extension portion abutting against the first leg portion and the second leg portion.

[Appendix 12]
A coil device as described in Appendix 7, wherein a first fixing member is attached from each of the first extension portion and the second extension portion, passing through a portion of the core located between the metal base substrate and the first cooling body and reaching the first cooling body.

[Appendix 13]
an insulating member is filled between the first extension portion and the second extension portion;
8. The coil device according to claim 7, further comprising a second fixing member attached to the insulating member and extending to the first cooling body.

[Appendix 14]
the first extension portion has a first extension length extending from the outer region of the core to the inner region of the core;
the second extension portion has a second extension length extending from the outer region of the core to the inner region of the core;
8. The coil device according to claim 7, wherein the first extension length is set to either a first length that is longer than the second extension length or a second length that is shorter than the second extension length.

[Appendix 15]
The core includes a first core and a second core arranged at a distance from each other in a first direction,
the cooling body includes a second cooling body disposed between the first core and the second core and thermally joined to the first cooling body;
A coil device described in any one of appendices 3 to 5, wherein the first wiring body and the second wiring body are wound around the first core and the second core, respectively, with the second cooling body interposed between the first core and the second core.

[Appendix 16]
The second cooling body is
a second cooling body first portion disposed on the first cooling body;
a second cooling body second part disposed so as to face the second cooling body first part,
A coil device as described in Appendix 15, wherein the second cooling body first part and the second cooling body second part are arranged to sandwich the wiring member from the side where the first cooling body is arranged and the side opposite to the side where the first cooling body is arranged.

[Appendix 17]
17. The coil device according to claim 16, wherein a heat conductive member is interposed between the second cooling body first portion and the wiring member, and between the second cooling body and the wiring member.

[Appendix 18]
18. The coil device according to any one of claims 15 to 17, wherein the second cooling body is arranged so as to be in contact with each of the first core and the second core.

[Appendix 19]
the first wiring main body includes a first wiring main body first portion and a first wiring main body second portion connected in series,
the second wiring main body includes a second wiring main body first portion and a second wiring main body second portion connected in series,
each of the first wiring body first portion, the first wiring body second portion, the second wiring body first portion, and the second wiring body second portion includes a portion extending in a first direction;
the first wiring body first portion and the first wiring body second portion, and the second wiring body first portion and the second wiring body second portion are arranged at a distance in a second direction intersecting the first direction,
the cores include a first core and a third core that are spaced apart from each other in the second direction,
the cooling bodies include a third cooling body, a fourth cooling body, and a fifth cooling body, each thermally joined to the first cooling body;
the third cooling body is disposed between the first core and the third core in a manner of contacting each of the first core and the third core,
the fourth cooling body is disposed on an opposite side of the first core from a side on which the third cooling body is disposed, in a manner in which the first core is sandwiched between the fourth cooling body and the third cooling body,
the fifth cooling body is disposed on an opposite side of the third core from a side on which the third cooling body is disposed, with the third core sandwiched between the fifth cooling body and the third cooling body;
the first wiring main body first portion and the second wiring main body first portion are each wound around the first core;
The coil device according to any one of appendices 3 to 5, wherein each of the first wiring main body second portion and the second wiring main body second portion is wound around the third core.

[Appendix 20]
the first wiring main body includes a first wiring main body first portion and a first wiring main body second portion connected in series,
the second wiring main body includes a second wiring main body first portion and a second wiring main body second portion connected in series,
each of the first wiring body first portion, the first wiring body second portion, the second wiring body first portion, and the second wiring body second portion includes a portion extending in a first direction;
the first wiring body first portion and the first wiring body second portion, and the second wiring body first portion and the second wiring body second portion are arranged at a distance in a second direction intersecting the first direction,
The core is
A first core;
a second core disposed at a distance from the first core in the first direction;
a third core disposed at a distance from the first core in the second direction;
a fourth core that is spaced apart from the third core in the first direction and spaced apart from the second core in the second direction,
the first wiring main body first portion and the second wiring main body first portion are wound around the first core and the second core, respectively;
the first wiring main body second portion and the second wiring main body second portion are wound around the third core and the fourth core, respectively;
the cooling body includes a lid cooling body thermally joined to the first cooling body and arranged to cover the first core, the second core, the third core, and the fourth core;
The coil device according to any one of appendices 3 to 5, wherein the lid cooling body is thermally bonded to the first core, the second core, the third core, and the fourth core.

[Appendix 21]
the cooling bodies include a second cooling body, a third cooling body, a fourth cooling body, a fifth cooling body, and a sixth cooling body, each thermally joined to the first cooling body;
the second cooling body is disposed between the first core and the second core,
the third cooling body is disposed between the first core and the third core so as to be in contact with each of the first core and the third core, and is disposed between the second core and the fourth core so as to be in contact with each of the second core and the fourth core,
the fourth cooling body is disposed on an opposite side of the first core and the second core from a side on which the third cooling body is disposed, with the first core and the second core sandwiched between the fourth cooling body and the third cooling body;
the fifth cooling body is disposed on an opposite side of the third core from a side on which the third cooling body is disposed, in a manner in which the third core and the fourth core are sandwiched between the fifth cooling body and the third cooling body;
21. The coil device according to claim 20, wherein the sixth cooling body is disposed between the third core and the fourth core.

[Appendix 22]
22. The coil device according to claim 20, wherein a heat conductive member is interposed between the lid cooling body and the first core, the second core, the third core, and the fourth core.

[Appendix 23]
A power conversion device comprising the coil device according to any one of appendices 1 to 22.

[Appendix 24]
an inverter circuit section electrically connected to the first coil pattern and disposed on the first metal base substrate;
24. The power conversion device according to claim 23, further comprising: a rectifier circuit section electrically connected to the second coil pattern and disposed on the second metal base substrate.

The present disclosure is effectively used in a coil device having a first winding section and a second winding section wound around a core, and a power conversion device equipped with a coil device.

1 Power conversion device, 2 Inverter circuit section, 3 Transformer section, 4 Rectifier circuit section, 5 Smoothing circuit section, 6 Input terminal, 7 Output terminal, 8 Input capacitor, 9, 9a, 9b, 9c, 9d Switching element, 10 Control circuit section, 11 Transformer, 11a Primary winding section, 11b Secondary winding section, 12, 12a, 12b, 12c, 12d Rectifier element, 13 Smoothing reactor, 14 Smoothing capacitor, 18 Coil unit, 20 Coil device, 21 Core, 21a First core, 21b Second core, 21c Third core, 21d Fourth core, 22a, 22b Corner portion, 23 E-shaped core, 23a, 23b, 23c Leg portion, 24 Inclined portion, 25 I-shaped core, 27 Slit portion, 29 First winding portion, 30 Second winding portion, 31 Metal base substrate, 31a: First metal base substrate, 31b: Second metal base substrate, 32, 32a, 32b, 32c: Insertion portion, 33a: First extension portion, 33b: Second extension portion, 34: Metal base body, 34a: First main surface, 34b: Second main surface, 35: Insulating layer, 35a: First main surface, 35b: Second main surface, 37: Coil pattern, 37a: First coil pattern, 37af: First coil pattern first portion, 37as: First coil pattern second portion, 37b: Second coil pattern, 37bf: Second coil pattern first portion, 37bs: Second coil pattern second portion, 38a: E-type cooling body, 38b: I-type cooling body, 38aa, 38ab, 38ac: Leg portion, 39: Cooling body, 39a: First cooling body, 39b: Second cooling body, 39c: Third cooling body, 39d Fourth cooling body, 39e Fifth cooling body, 39f Sixth cooling body, 39g Lid cooling body, 39aa Main surface, 40 Groove portion, 41 Wiring member, 42, 42a, 42b, 42c, 42d, 42e Insertion portion, 43 Insulating portion, 43a First main surface, 43b Second main surface, 45 Wiring body, 45a First wiring body, 45aa First wiring body first portion, 45ab First wiring body second portion, 45b Second wiring body, 45ba Second wiring body first portion, 45bb Second wiring body second portion, 47 Through-hole conductive portion, 53 Jointing member, 55 Sealing member, 57 Elastic member, 59 Concave and convex portions, 61a, 61b Step portions, 63a, 63b Upwardly curved portions, 65a, 65b Downwardly curved portions, 67 Convex portion, 69, 73, 74 screw member, 71 insulating member, 75, 76, 77 heat conduction member, RP induced current, TA, TB terminal, CR creepage distance, SL, CW, CD length, TA, TB terminal, WA, WB width, DL spacing, CP center, EFL, ESL length, PT1 current path, PT2 current path.

Claims (21)

A coil device having a coil unit,
The coil unit includes:
one or more cores having a looped magnetic path;
a metal base substrate disposed in an inner region of the core and an outer region of the core, the metal base substrate having a first coil pattern formed on a metal base body with an insulating layer interposed therebetween;
a first winding portion including the first coil pattern and wound around the core in a manner passing through the inner region of the core;
Equipped with
The metal base substrate is
a first metal base substrate on which the first coil pattern is formed ;
a second metal base substrate;
A coil device in which the first metal base substrate and the second metal base substrate are arranged facing each other, with an insertion portion through which the core is inserted formed between the first metal base substrate and the second metal base substrate. a second coil pattern is formed on the second metal base substrate with the insulating layer interposed between the metal base body and the second metal base substrate;
a second winding portion including the second coil pattern, wound around the core in a manner passing through the inner region of the core, and electrically insulated from the first winding portion;
one or more cooling bodies including a first cooling body joined to the metal base body on the side opposite to the side on which the insulating layer is formed;
The coil device of claim 1 , further comprising: a slit portion that prevents a loop-shaped induced current from flowing in a portion surrounding the core is formed in the metal base substrate in a manner that the slit portion is connected to the insertion portion;
2. The coil device according to claim 1, wherein the first metal base substrate and the second metal base substrate are arranged at a distance corresponding to the slit portion. a wiring member including a wiring main body wound around the core,
The first coil pattern is
a first coil pattern first portion;
a first coil pattern second portion;
The second coil pattern is
a first portion of a second coil pattern;
a second coil pattern second portion;
The wiring body is
a first wiring main body electrically connecting the first coil pattern first portion and the first coil pattern second portion;
a second wiring main body electrically connecting the second coil pattern first portion and the second coil pattern second portion,
the first winding portion includes the first wiring main body,
The coil device according to claim 2 , wherein the second winding portion includes the second wiring body. the wiring member is a printed circuit board,
The coil device according to claim 4 , wherein the wiring body is disposed on the printed circuit board. the wiring member is located in the inner region of the core and the outer region of the core, surrounded by the core, on the opposite side of the metal base substrate from the side where the first cooling body is located,
a receiving groove portion for receiving the core is formed in the first cooling body;
5. The coil device according to claim 4 , wherein a sealing material is filled between the wiring member and the metal base substrate and between the receiving groove and the core. 3. The coil device according to claim 2 , wherein a biasing member is interposed between said metal base substrate and said core. the first metal base substrate includes a first extension portion extending from the outer region of the core to the inner region of the core;
the second metal base substrate includes a second extension portion extending from the outer region of the core to the inner region of the core;
3. The coil device according to claim 2 , wherein the first metal base substrate and the second metal base substrate are arranged such that the first extending portion and the second extending portion face each other. The coil device of claim 8, wherein the first extension portion and the second extension portion have a clamping portion formed thereon that sandwiches the portion of the core located between the metal base substrate and the first cooling body between the first extension portion and the second extension portion. The coil device of claim 8, wherein the first extension portion and the second extension portion have a warped portion that sandwiches the portion of the core located between the metal base substrate and the first cooling body between the metal base substrate and the first cooling body and urges the portion toward the first cooling body. The coil device according to claim 8, wherein the core has a protrusion formed thereon that protrudes from a portion of the core located between the metal base substrate and the first cooling body toward a portion between the first extension portion and the second extension portion. The core is
a first leg portion around which the first winding portion and the second winding portion are wound;
a second leg portion positioned at a first distance from the first leg portion;
the first extension portion and the second extension portion are located between the first leg portion and the second leg portion so as to face each other,
the first extension portion is formed so that its width narrows from a first width wider than the first interval to a second width narrower than the first interval toward a tip of the first extension portion,
the second extension portion is formed so that its width narrows from a third width wider than the first interval to a fourth width narrower than the first interval toward a tip of the second extension portion,
The coil device of claim 8, wherein the metal base substrate is arranged to sandwich the core, with the first extension portion abutting against the first leg portion and the second leg portion, and the second extension portion abutting against the first leg portion and the second leg portion. The coil device of claim 8, wherein a first fixing member is attached from each of the first extension portion and the second extension portion, passing through a portion of the core located between the metal base substrate and the first cooling body and reaching the first cooling body. an insulating member is provided between the first extension portion and the second extension portion;
9. The coil device according to claim 8 , further comprising a second fixing member attached to the insulating member and extending to the first cooling body. the first extension portion has a first extension length extending from the outer region of the core to the inner region of the core;
the second extension portion has a second extension length extending from the outer region of the core to the inner region of the core;
The coil device according to claim 8 , wherein the first extension length is set to either a first length longer than the second extension length or a second length shorter than the second extension length. The core includes a first core and a second core arranged at a distance from each other in a first direction,
the cooling body includes a second cooling body disposed between the first core and the second core and thermally joined to the first cooling body;
5. The coil device according to claim 4, wherein the first wiring body and the second wiring body are wound around the first core and the second core, respectively, with the second cooling body interposed between the first core and the second core. The second cooling body is
a second cooling body first portion disposed on the first cooling body;
a second cooling body second part disposed so as to face the second cooling body first part,
The coil device of claim 16, wherein the second cooling body first part and the second cooling body second part are arranged to sandwich the wiring member from the side where the first cooling body is arranged and the side opposite to the side where the first cooling body is arranged. the first wiring main body includes a first wiring main body first portion and a first wiring main body second portion connected in series,
the second wiring main body includes a second wiring main body first portion and a second wiring main body second portion connected in series,
each of the first wiring body first portion, the first wiring body second portion, the second wiring body first portion, and the second wiring body second portion includes a portion extending in a first direction;
the first wiring body first portion and the first wiring body second portion, and the second wiring body first portion and the second wiring body second portion are arranged at a distance in a second direction intersecting the first direction,
the cores include a first core and a third core that are spaced apart from each other in the second direction,
the cooling bodies include a third cooling body, a fourth cooling body, and a fifth cooling body, each thermally joined to the first cooling body;
the third cooling body is disposed between the first core and the third core in a manner of contacting each of the first core and the third core,
the fourth cooling body is disposed on an opposite side of the first core from a side on which the third cooling body is disposed, in a manner in which the first core is sandwiched between the fourth cooling body and the third cooling body,
the fifth cooling body is disposed on an opposite side of the third core from a side on which the third cooling body is disposed, with the third core sandwiched between the fifth cooling body and the third cooling body;
the first wiring main body first portion and the second wiring main body first portion are each wound around the first core;
The coil device according to claim 4 , wherein the first wiring main body second portion and the second wiring main body second portion are each wound around the third core. the first wiring main body includes a first wiring main body first portion and a first wiring main body second portion connected in series,
the second wiring main body includes a second wiring main body first portion and a second wiring main body second portion connected in series,
each of the first wiring body first portion, the first wiring body second portion, the second wiring body first portion, and the second wiring body second portion includes a portion extending in a first direction;
the first wiring body first portion and the first wiring body second portion, and the second wiring body first portion and the second wiring body second portion are arranged at a distance in a second direction intersecting the first direction,
The core is
A first core;
a second core disposed at a distance from the first core in the first direction;
a third core disposed at a distance from the first core in the second direction;
a fourth core that is spaced apart from the third core in the first direction and spaced apart from the second core in the second direction,
the first wiring main body first portion and the second wiring main body first portion are wound around the first core and the second core, respectively;
the first wiring main body second portion and the second wiring main body second portion are wound around the third core and the fourth core, respectively;
the cooling body includes a lid cooling body thermally joined to the first cooling body and arranged to cover the first core, the second core, the third core, and the fourth core;
The coil device according to claim 4 , wherein the lid cooling body is thermally bonded to the first core, the second core, the third core, and the fourth core. A power conversion device comprising the coil device according to any one of claims 1 to 19 . an inverter circuit section electrically connected to the first coil pattern and disposed on the first metal base substrate ;
The power conversion device according to claim 20 , further comprising a rectifier circuit portion disposed on the second metal base substrate.