JP7564451B2 - Power Conversion Equipment - Google Patents

Description

Related to power conversion devices.

Patent document 1 (JP 2018-148629 A) shows an invention in which a capacitor and a reactor, which are components of a power conversion device, are mounted on the same board.

However, if the power conversion circuit and reactor are mounted on the same board, the reactor will generate a lot of heat if the power quality is poor or if the switching speed is increased. If the reactor generates a lot of heat, a board with high heat resistance must be used, but this increases the manufacturing costs of the power conversion device.

The power conversion device of the first aspect includes a power conversion circuit, a reactor, and a substrate. The power conversion circuit has a power semiconductor. The reactor has a core and a winding. The power conversion circuit and the reactor are mounted on the same substrate. Of the windings of the reactor, the wire wound around the core is made of a material with a higher electrical resistivity (Ω·m) at 20°C than copper.

Here, instead of the reactors that have been conventionally and generally used in power conversion devices, a reactor that generates less heat is used. Specifically, the power conversion device of the first aspect employs a reactor in which a wire made of a material with a higher electrical resistivity at 20°C than copper is used as the wire wound around at least the core of the winding. With this power conversion device, the amount of heat generated by the reactor is kept low, eliminating the need to use an expensive substrate with good heat resistance, and reducing the manufacturing costs of the power conversion device.

The power conversion device of the second aspect is the power conversion device of the first aspect, in which the wire of the reactor winding that is wound around the core is an aluminum wire.

Here, aluminum wire, which has an electrical resistivity (Ω·m) at 20°C that is 1.5 times that of copper wire, is used as the wire wound around at least the core of the reactor winding. By using such a reactor, the amount of heat generated by the reactor is kept low in this power conversion device.

The power conversion device of the third aspect is the power conversion device of the first or second aspect, in which the reactor further has a connection part that is connected to the power conversion circuit. The connection part is made of copper.

Here, the reactor connection is made of copper, so the reactor can be easily connected to the power conversion circuit with solder, just like in conventional power conversion devices.

The power conversion device of the fourth aspect is the power conversion device of the first or second aspect, and the reactor further has a connection part that is connected to the power conversion circuit. The connection part is made of plated aluminum.

In this case, the connection part of the reactor is plated aluminum, so the plated part can be easily connected to the power conversion circuit by soldering. For example, if the copper-plated part of the aluminum wire is used as the connection part of the reactor, the reactor can be easily connected to the power conversion circuit.

The power conversion device of the fifth aspect is a power conversion device of any one of the first aspect to the fourth aspect, in which the inductance of the reactor is 1 mH or less at the rated current.

The power conversion device of the sixth aspect is the power conversion device of any one of the first aspect to the fifth aspect, in which a current of 10 A or more flows through the reactor.

The power conversion device of the seventh aspect is the power conversion device of the sixth aspect, in which a current of 100 A or less flows through the reactor.

The power conversion device of the eighth aspect is a power conversion device of any one of the first aspect to the seventh aspect, in which the substrate has a base material and a copper foil bonded to the base material. The thickness of the copper foil is 30 μm or more and 75 μm or less.

The power conversion device of the ninth aspect is the power conversion device of any one of the first aspect to the eighth aspect, in which the substrate has a base material and a copper foil bonded to the base material. The base material is a glass epoxy or a glass composite.

The power conversion device of the tenth aspect is a power conversion device of any one of the first to ninth aspects, in which the power supply voltage is single-phase or three-phase, and is 200V or more and 240V or less.

1 is a schematic configuration diagram of an air conditioning device including a power conversion device. 2 is a cross-sectional view of the outdoor unit of the air conditioning apparatus. FIG. 1 is a front view showing the outdoor unit with the front panel on the blower chamber side and the front panel on the machine chamber side removed. FIG. FIG. 2 is a schematic diagram of an electric circuit of the power conversion device. FIG. 2 is a schematic layout diagram of main components on a printed circuit board. FIG. FIG.

(1) Overall Configuration of the Air Conditioner FIG. 1 is a schematic diagram of an air conditioner 1 that performs a refrigeration cycle.

The air conditioner 1 is a device that cools and heats the interior of a building or the like by using a vapor compression refrigeration cycle. The air conditioner 1 is mainly composed of an outdoor unit 2 and an indoor unit 4 connected together. Here, the outdoor unit 2 and the indoor unit 4 are connected via a liquid refrigerant connection pipe 5 and a gas refrigerant connection pipe 6.

(1-1) Indoor Unit The indoor unit 4 is installed indoors and constitutes a part of the refrigerant circuit 10. The indoor unit 4 has an indoor heat exchanger 41 as a main component.

The indoor heat exchanger 41 is a heat exchanger that functions as a refrigerant evaporator to cool the indoor air during cooling operation, and functions as a refrigerant radiator to heat the indoor air during heating operation. The liquid side of the indoor heat exchanger 41 is connected to the liquid refrigerant connection pipe 5, and the gas side of the indoor heat exchanger 41 is connected to the gas refrigerant connection pipe 6.

The indoor unit 4 has an indoor fan 42 that draws indoor air into the indoor unit 4, exchanges heat with the refrigerant in the indoor heat exchanger 41, and then supplies the air to the room as supply air. That is, the indoor unit 4 has the indoor fan 42 as a fan that supplies indoor air to the indoor heat exchanger 41 as a heating or cooling source for the refrigerant flowing through the indoor heat exchanger 41. Here, a centrifugal fan or a multi-blade fan driven by an indoor fan motor 42a is used as the indoor fan 42.

The indoor unit 4 has an indoor control unit 40 that controls the operation of each part that constitutes the indoor unit 4. The indoor control unit 40 has a microcomputer, memory, etc. that are provided to control the indoor unit 4, and is capable of exchanging control signals with a remote control (not shown) and with the outdoor unit 2.

(1-2) Outdoor Unit The outdoor unit 2 is installed outdoors and constitutes a part of the refrigerant circuit 10. The outdoor unit 2 mainly has a compressor 21, a four-way switching valve 22, an outdoor heat exchanger 23, a refrigerant jacket 29, an expansion valve 26, a liquid-side shut-off valve 27, and a gas-side shut-off valve 28.

The compressor 21 is a device that compresses the low-pressure refrigerant of the refrigeration cycle until it becomes high pressure. The compressor 21 has a sealed structure that rotates a volumetric compression element (not shown), such as a rotary type or scroll type, by a compressor motor 21a that is supplied with power through a power conversion device 100 described below. The compressor 21 has a suction pipe 31 connected to the suction side and a discharge pipe 32 connected to the discharge side. The suction pipe 31 is a refrigerant pipe that connects the suction side of the compressor 21 to the four-way switching valve 22. The discharge pipe 32 is a refrigerant pipe that connects the discharge side of the compressor 21 to the four-way switching valve 22.

The four-way switching valve 22 is a switching valve for switching the direction of refrigerant flow in the refrigerant circuit 10. During cooling operation, the four-way switching valve 22 switches to a cooling cycle state in which the outdoor heat exchanger 23 functions as a radiator for the refrigerant compressed in the compressor 21 and the indoor heat exchanger 41 functions as an evaporator for the refrigerant that has radiated heat in the outdoor heat exchanger 23. During heating operation, the four-way switching valve 22 switches to a heating cycle state in which the indoor heat exchanger 41 functions as a radiator for the refrigerant compressed in the compressor 21 and the outdoor heat exchanger 23 functions as an evaporator for the refrigerant that has radiated heat in the indoor heat exchanger 41.

The outdoor heat exchanger 23 is a heat exchanger that functions as a radiator of the refrigerant using the outdoor air as a cooling source during cooling operation, and as an evaporator of the refrigerant using the outdoor air as a heating source during heating operation.

The expansion valve 26 is a valve that reduces the pressure of the high-pressure refrigerant in the refrigeration cycle that has dissipated heat in the outdoor heat exchanger 23 to the low pressure of the refrigeration cycle during cooling operation. Also, the expansion valve 26 is a valve that reduces the pressure of the high-pressure refrigerant in the refrigeration cycle that has dissipated heat in the indoor heat exchanger 41 to the low pressure of the refrigeration cycle during heating operation.

The refrigerant jacket 29 is a heat exchanger that uses the refrigerant circulating through the refrigerant circuit 10 to cool the elements to be cooled (diodes D1 to D6, which are power semiconductors, and switching elements SW1 to SW6) that generate a large amount of heat and need to be cooled among the electrical components that make up the electrical component unit 70 described below. Specifically, the refrigerant jacket 29 cools the elements to be cooled using the refrigerant flowing through the liquid refrigerant pipe 35. The liquid refrigerant pipe 35 is a refrigerant pipe that connects the outdoor heat exchanger 23 and the liquid refrigerant connection pipe 5. During cooling operation, the refrigerant jacket 29 functions as a heat exchanger that cools the elements to be cooled using the high-pressure refrigerant of the refrigeration cycle after heat dissipation in the outdoor heat exchanger 23 (the refrigerant flowing between the outdoor heat exchanger 23 and the expansion valve 26), and during heating operation, it functions as a heat exchanger that cools the elements to be cooled using the low-pressure refrigerant of the refrigeration cycle after pressure reduction by the expansion valve 26 (the refrigerant flowing between the expansion valve 26 and the outdoor heat exchanger 23).

The liquid side shutoff valve 27 and the gas side shutoff valve 28 are valves provided at the connection ports to external equipment and piping (specifically, the liquid refrigerant connection pipe 5 and the gas refrigerant connection pipe 6). The liquid side shutoff valve 27 is provided at the end of the liquid refrigerant pipe 35. The gas side shutoff valve 28 is provided at the end of the second gas refrigerant pipe 34.

The outdoor unit 2 has an outdoor fan 36 that draws outdoor air into the outdoor unit 2, exchanges heat with the refrigerant in the outdoor heat exchanger 23, and then expels the air to the outside. Here, a propeller fan driven by an outdoor fan motor 36a is used as the outdoor fan 36.

The outdoor unit 2 has an outdoor side control unit 20 that controls the operation of each part that constitutes the outdoor unit 2. The outdoor side control unit 20 has a microcomputer, memory, etc. that are provided to control the outdoor unit 2, and is capable of exchanging control signals and the like with the indoor side control unit 40 of the indoor unit 4. The outdoor side control unit 20 is provided in the electrical equipment unit 70, which will be described later.

(1-3) Refrigerant communication pipe The refrigerant communication pipes 5, 6 are refrigerant pipes that are installed on-site when the air conditioning apparatus 1 is installed at an installation location such as a building, and refrigerant communication pipes of various lengths and pipe diameters are used depending on the installation conditions, such as the installation location and the combination of the outdoor unit and the indoor unit.

As described above, the outdoor unit 2, the indoor unit 4, and the refrigerant connection pipes 5 and 6 are connected to form the refrigerant circuit 10 of the air conditioning device 1.

(1-4) Control Unit The air conditioning device 1 is configured to control each device of the outdoor unit 2 and the indoor unit 4 by a control unit 8 composed of an indoor side control unit 40 and an outdoor side control unit 20. That is, the indoor side control unit 40 and the outdoor side control unit 20 constitute the control unit 8 that controls the operation of the entire air conditioning device 1, including the refrigeration cycle operations such as the cooling operation and heating operation. The control unit 8 is mainly realized by a computer. The control unit 8 includes a control arithmetic device and a storage device. A processor such as a CPU or a GPU can be used for the control arithmetic device. The control arithmetic device reads a program stored in the storage device and performs predetermined image processing and arithmetic processing according to the program. Furthermore, the control arithmetic device can write the calculation results to the storage device and read information stored in the storage device according to the program.

(2) Detailed Configuration of Outdoor Unit Next, a detailed configuration of the outdoor unit 2 will be described with reference to Figures 2 and 3. In the following description, terms indicating directions or surfaces, such as "upper", "lower", "left", "right", "front", "side", "rear", "top", and "bottom", refer to directions or surfaces when the outdoor unit 2 shown in Figure 3 is regarded as the front surface, unless otherwise specified.

The outdoor unit 2 has a structure in which the internal space of the unit casing 50 is divided into left and right spaces by a vertically extending partition plate 57, forming a blower chamber S1 and a machine chamber S2. The outdoor unit 2 is configured to draw outdoor air into the unit casing 50 from the rear and part of the side, and then discharge the air from the front of the unit casing 50. The outdoor unit 2 mainly has the unit casing 50, refrigerant circuit components, an outdoor fan 36, and an electrical equipment unit 70 in which multiple electrical equipment is provided. As described above, the refrigerant circuit components include the compressor 21, the four-way switching valve 22, the outdoor heat exchanger 23, the expansion valve 26, the refrigerant jacket 29, the shutoff valves 27 and 28, and the refrigerant pipes connecting these devices.

The unit casing 50 is formed in a roughly rectangular parallelepiped shape and mainly houses the refrigerant circuit components 21-28, the outdoor fan 36, and the electrical equipment unit 70. The unit casing 50 has a bottom plate 51, a side plate 52 on the blower room side, a side plate 53 on the machine room side, a front plate 54 on the blower room side, a front plate 55 on the machine room side, and a top plate 56.

The electrical equipment unit 70 is disposed in the machine room S2 so as to be located near the front of the unit casing 50. The electrical equipment unit 70 is a unit provided with multiple electrical components used for controlling the equipment in the outdoor unit 2, and is provided with an outdoor side control unit 20. The electrical equipment unit 70 mainly has a printed circuit board 71 and multiple electrical components including a cooled element used to supply power to the compressor motor 21a, a reactor 121, a capacitor 122, and the outdoor side control unit 20. The multiple electrical components are mounted on the main surface 71a (the surface facing the front side of the outdoor unit 2) of the printed circuit board 71, which is arranged horizontally in a vertical plane.

The refrigerant jacket 29 is a vertically elongated member that runs along the length of the U-shaped bent portion of the liquid refrigerant tube 35, and is supported on the printed circuit board 71. The refrigerant jacket 29 has a structure in which the liquid refrigerant tube 35 is mounted, bent in a U-shape so as to be folded back in the vertical direction. The refrigerant jacket 29 is arranged to cover the front side of the cooled elements mounted on the main surface 71a of the printed circuit board 71, and is in thermal contact with the cooled elements. The cooled elements include the diodes D1 to D6 of the converter circuit 110, the switching elements SW1 to SW6 and the reflux diodes RD1 to RD6 of the inverter circuit 130, which will be described later.

Although not shown here, refrigerant circuit components such as the four-way switching valve 22 and the expansion valve 26 are also arranged inside the unit casing 50. The detailed configuration of the electrical equipment unit 70, including the power conversion device 100 and the refrigerant jacket 29, will be described later.

(3) Basic Operation of the Air Conditioner Next, the basic operation of the air conditioner 1 will be described with reference to Fig. 1. As a basic operation, the air conditioner 1 performs cooling operation and heating operation while cooling the cooled elements by the refrigerant jacket 29. The cooling operation and heating operation are performed by the control unit 8.

(3-1) Cooling Operation During cooling operation, the four-way switching valve 22 is switched to the cooling cycle state (the state shown by the solid line in FIG. 1).

In the refrigerant circuit 10, low-pressure gas refrigerant in the refrigeration cycle is drawn into the compressor 21, compressed to the high pressure of the refrigeration cycle, and then discharged.

The high-pressure gas refrigerant discharged from the compressor 21 is sent to the outdoor heat exchanger 23 through the four-way switching valve 22.

The high-pressure gas refrigerant sent to the outdoor heat exchanger 23 exchanges heat with the outdoor air supplied as a cooling source by the outdoor fan 36 in the outdoor heat exchanger 23, dissipating heat and becoming a high-pressure liquid refrigerant.

The high-pressure liquid refrigerant that has dissipated heat in the outdoor heat exchanger 23 is sent to the refrigerant jacket 29.

The high-pressure liquid refrigerant sent to the refrigerant jacket 29 exchanges heat with the element to be cooled and is heated. At this time, the element to be cooled is cooled according to the flow rate and temperature of the high-pressure liquid refrigerant flowing through the refrigerant jacket 29.

The high-pressure liquid refrigerant heated in the refrigerant jacket 29 is sent to the expansion valve 26.

The high-pressure liquid refrigerant sent to the expansion valve 26 is reduced in pressure to the low pressure of the refrigeration cycle by the expansion valve 26, becoming a low-pressure two-phase gas-liquid refrigerant. The low-pressure two-phase gas-liquid refrigerant reduced in pressure by the expansion valve 26 is sent to the indoor heat exchanger 41 through the liquid-side shutoff valve 27 and the liquid refrigerant connection pipe 5.

The low-pressure gas-liquid two-phase refrigerant sent to the indoor heat exchanger 41 evaporates in the indoor heat exchanger 41 through heat exchange with indoor air supplied as a heat source by the indoor fan 42. This cools the indoor air, which is then supplied to the room to cool it.

The low-pressure gas refrigerant that has evaporated in the indoor heat exchanger 41 is sucked back into the compressor 21 through the gas refrigerant connection pipe 6, the gas side shutoff valve 28, and the four-way switching valve 22.

(3-2) Heating Operation During heating operation, the four-way selector valve 22 is switched to the heating cycle state (the state shown by the dashed line in FIG. 1).

In the refrigerant circuit 10, low-pressure gas refrigerant in the refrigeration cycle is drawn into the compressor 21, compressed to the high pressure of the refrigeration cycle, and then discharged.

The high-pressure gas refrigerant discharged from the compressor 21 is sent to the indoor heat exchanger 41 through the four-way switching valve 22, the gas side shutoff valve 28, and the gas refrigerant connection pipe 6.

The high-pressure gas refrigerant sent to the indoor heat exchanger 41 exchanges heat with indoor air supplied as a cooling source by the indoor fan 42 in the indoor heat exchanger 41, dissipating heat and becoming high-pressure liquid refrigerant. This heats the indoor air, which is then supplied to the room to heat the room.

The high-pressure liquid refrigerant that has dissipated heat in the indoor heat exchanger 41 is sent to the expansion valve 26 through the liquid refrigerant connection pipe 5 and the liquid side shutoff valve 27.

The high-pressure liquid refrigerant sent to the expansion valve 26 is reduced in pressure to the low pressure of the refrigeration cycle by the expansion valve 26, becoming a low-pressure two-phase gas-liquid refrigerant. The low-pressure two-phase gas-liquid refrigerant reduced in pressure by the expansion valve 26 is sent to the refrigerant jacket 29.

The low-pressure gas-liquid two-phase refrigerant sent to the refrigerant jacket 29 is heated by heat exchange with the element to be cooled. At this time, the element to be cooled is cooled according to the flow rate (i.e., the amount of refrigerant circulating) and temperature of the low-pressure gas-liquid two-phase refrigerant flowing through the refrigerant jacket 29.

The low-pressure gas-liquid two-phase refrigerant heated in the refrigerant jacket 29 is sent to the outdoor heat exchanger 23.

The low-pressure gas-liquid two-phase refrigerant sent to the outdoor heat exchanger 23 exchanges heat with the outdoor air supplied as a heat source by the outdoor fan 36 in the outdoor heat exchanger 23, evaporating and becoming a low-pressure gas refrigerant.

The low-pressure refrigerant that has evaporated in the outdoor heat exchanger 23 is sucked back into the compressor 21 through the four-way switching valve 22.

(4) Configuration of Electrical Component Unit of Outdoor Unit As described above, the electrical component unit 70 of the outdoor unit 2 has the printed circuit board 71, a plurality of electrical components mounted on the printed circuit board 71, and the refrigerant jacket 29 for cooling the electrical components that require cooling (elements to be cooled). The printed circuit board 71 and some of the electrical components mounted on the printed circuit board 71 constitute the power conversion device 100 that supplies power to the motor 21a for the compressor.

(4-1) Power Conversion Device The power conversion device 100 converts the power supplied from the AC power source 102 into a predetermined frequency and then applies it to the motor 21a. The motor 21a is a three-phase AC motor. As shown in FIG. 4, the power conversion device 100 mainly includes a converter circuit 110, which is a power conversion circuit that converts AC to DC, a reactor 121, a capacitor 122, an inverter circuit 130, which is a power conversion circuit that converts DC to AC, and a control circuit 150. These circuits 110, 130, and 150 are configured by the patterns of a printed circuit board 71 and electrical components mounted on the printed circuit board 71. The reactor 121 and the capacitor 122 are also mounted on the printed circuit board 71 on which the circuits 110, 130, and 150 are formed. The printed circuit board 71 is connected to the AC power source 102 via a harness.

(4-1-1) AC Power Supply The AC power supply 102 supplies power to the power conversion device 100 and the motor 21a. Specifically, the AC power supply 102 is a so-called commercial three-phase AC power supply, and supplies an AC voltage having a frequency of 50 Hz, 60 Hz, etc. The power supply voltage of the AC power supply 102 is single-phase or three-phase, and is 200 V or more and 240 V or less.

(4-1-2) Converter Circuit The converter circuit 110 is connected to the AC power supply 102, and converts the AC voltage output by the AC power supply 102 into a DC voltage by full-wave rectification. The converter circuit 110 is configured by a diode bridge circuit in which six diodes D1 to D6, which are power semiconductors, are connected in a bridge shape. The diodes D1 and D2, the diodes D3 and D4, and the diodes D5 and D6 are connected in series, respectively. The connection point of the diodes D1 and D2 is connected to the R-phase output of the AC power supply 102. The connection point of the diodes D3 and D4 is connected to the S-phase output of the AC power supply 102. The connection point of the diodes D5 and D6 is connected to the T-phase output of the AC power supply 102. The converter circuit 110 rectifies the AC voltage output from the AC power supply 102.

(4-1-3) Reactor The reactor 121 is provided between the converter circuit 110 and the inverter circuit 130, and is connected in series with the converter circuit 110 and the inverter circuit 130. As shown in Fig. 6 and Fig. 7, the reactor 121 mainly has a core 201, a winding 202, a terminal 203, and a pin 121a. As shown in Fig. 5, the converter circuit 110 and the inverter circuit 130, which are power conversion circuits, and the reactor 121 are mounted on the same printed circuit board 71. The reactor 121 is fixed to the printed circuit board 71 via the terminal 203 and a plurality of pins 121a.

Of the windings 202 of the reactor 121, the wire 202a wound around the core 201 is a wire made of a material having a higher electrical resistivity (Ω·m) at 20° C. than copper. Here, an aluminum wire is used as the windings 202 of the reactor 121. The electrical resistivity (Ω·m) of aluminum wire at 20° C. is 1.5 times or more that of copper wire. The electrical resistivity of copper at 20° C. is approximately 1.7×10 ^-8 (Ω·m). Here, aluminum having an electrical resistivity of 2.6×10 ^-8 (Ω·m) to 2.9×10 ^-8 (Ω·m) at 20° C. is used as the material of the aluminum wire used as the windings 202.

The terminal 203, which is the connection part of the reactor 121, is a thin plate member made of copper-plated aluminum. The terminal 203 is soldered to the pattern (copper foil) of the printed circuit board 71 and is connected to the converter circuit 110 and the inverter circuit 130.

The inductance of reactor 121 is 1 mH or less at rated current.

A current of 20 A or more and 100 A or less flows through reactor 121.

(4-1-4) Capacitor The capacitor 122 is provided between the converter circuit 110 and the inverter circuit 130, and is connected in parallel with the converter circuit 110 and the inverter circuit 130. One end of the capacitor 122 is connected to the positive output terminal of the converter circuit 110 via the reactor 121, and the other end is connected to the negative output terminal of the converter circuit 110. A DC voltage generated across the capacitor 122 is connected to the input node of the inverter circuit 130. In this embodiment, a film capacitor is used as the capacitor 122.

(4-1-5) Inverter Circuit The inverter circuit 130 inversely converts the voltage rectified by the converter circuit 110 into an AC voltage of a predetermined frequency based on the input of a gate control signal, and applies the converted voltage to the motor 21a. Here, the input node of the inverter circuit 130 is connected in parallel to the capacitor 122. The inverter circuit 130 includes six switching elements SW1 to SW6, which are power semiconductors, in order to output three-phase AC to the motor 21a. More specifically, the inverter circuit 130 includes three switching legs each including two switching elements connected in series to each other, and in each switching leg, the connection points between the switching elements SW1, SW3, and SW5 of the upper arm and the switching elements SW2, SW4, and SW6 of the lower arm are connected to the coils of each phase (U-phase, V-phase, and W-phase) of the motor 21a. In addition, freewheel diodes RD1 to RD6 are connected in inverse parallel to each of the switching elements SW1 to SW6. The inverter circuit 130 switches the input voltage by turning on and off these switching elements SW1 to SW6, converts it into a three-phase AC voltage, and supplies it to the motor 21a. The on and off operations are controlled by a control circuit 150. Each of the switching elements SW1 to SW6 is realized by, for example, an insulated gate bipolar transistor (IGBT).

(4-1-6) Control Circuit The control circuit 150 executes various controls in the power conversion device 100. Specifically, the control circuit 150 is mainly composed of a microcomputer, and controls the on/off operation of each of the switching elements SW1 to SW6 of the inverter circuit 130 to drive the motor 21a of the compressor 21.

(4-1-7) Printed Circuit Board The printed circuit board 71 is a double-sided board, and is a glass epoxy board with a board thickness of 1.6 mm. The printed circuit board 71 has a base material (glass epoxy material) made of a material in which glass cloth is impregnated with epoxy resin, and copper foil bonded to the base material. The thickness of the copper foil is 30 μm or more and 75 μm or less. Here, copper foil with a thickness of 35 μm to 40 μm is bonded to the base material. The printed circuit board 71 is a board having general heat resistance, conforming to the NEMA standard of FR-4.

(4-2) Coolant Jacket As described above, the coolant jacket 29 is a member supported on the printed circuit board 71, and cools the diodes D1 to D6 of the converter circuit 110, the switching elements SW1 to SW6 and the freewheeling diodes RD1 to RD6 of the inverter circuit 130, and the like.

(5) Features of the power conversion device (5-1)
In the power conversion device 100 provided for the motor 21a for the compressor in the outdoor unit 2 of the air conditioner 1, the reactor 121 is mounted on the same printed circuit board 71 together with the converter circuit 110 and the inverter circuit 130. The power conversion device 100 employs a reactor 121 having an aluminum wire as a winding 202 and suppressing the amount of heat generated, instead of a reactor having a copper wire as a winding, which has been conventionally generally used in power conversion devices. Specifically, the power conversion device 100 employs a reactor 121 in which an aluminum wire having a higher electrical resistivity at 20°C than copper is used as the winding 202. According to this power conversion device 100, the amount of heat generated by the reactor 121 is suppressed to a low level, so that it is not necessary to use an expensive printed circuit board with good heat resistance, and the manufacturing cost of the power conversion device 100 is suppressed. Specifically, the power conversion device 100 employs a printed circuit board 71 having general heat resistance and conforming to the NEMA standard of FR-4.

In other words, the power conversion device 100 employs a reactor 121 in which the winding 202 is made of aluminum wire and the amount of heat generated is suppressed by increasing the resistance of the winding 202. This suppresses abnormal heat generation in the reactor 121 caused by high-frequency voltage distortion due to power supply distortion. When the resistance of the winding 202 increases, the waveform of the power supply distortion becomes dull, making it less likely that abnormal heat will occur in the reactor 121.

In addition, when increasing the switching speed, there is a risk of abnormal heat generation in a conventional reactor that uses copper wire as a winding, but the power conversion device 100 suppresses abnormal heat generation in the reactor 121.

(5-2)
In the power conversion device 100, an aluminum wire having an electrical resistivity (Ω·m) at 20° C. that is 1.5 times or more that of a copper wire is used as the winding 202 of the reactor 121. Since such a reactor 121 is used, in the power conversion device 100, the amount of heat generated by the reactor is kept considerably small.

(5-3)
In the power conversion device 100, the terminal 203 which is the connecting portion of the reactor 121 is made of copper-plated aluminum. Therefore, the copper-plated portion can be easily connected to the pattern made of copper foil of the printed circuit board 71 by soldering.

(6) Modification (6-1)
In the above-described power conversion device 100, the terminal 203, which is the connection portion of the reactor 121, is made of copper-plated aluminum. Alternatively, a plate member made of copper may be used as the terminal of the reactor 121. In this case, too, the reactor can be easily soldered to a printed circuit board and connected to a converter circuit or an inverter circuit, as in the case of a conventional power conversion device.

(6-2)
In the above-described power conversion device 100, the terminal 203 which is the connecting portion of the reactor 121 is made of aluminum plated with copper, but aluminum plated with a material other than copper may be used.

(6-3)
In the above-described power conversion device 100, the entire winding 202 of the reactor 121 is made of aluminum wire, but only the wire wound around the core of the winding may be made of aluminum wire.

(6-4)
In the above-described power conversion device 100, the winding 202 of the reactor 121 is made of aluminum wire, but a wire other than aluminum wire may be used as long as the wire is made of a material having a higher electrical resistivity (Ω·m) at 20° C. than copper.

(6-5)
The above-described power conversion device 100 employs one reactor 121, and the current flowing through the reactor 121 is equal to or more than 20 A and equal to or less than 100 A. If a power conversion device using two or more reactors is used instead of this configuration, the current flowing through each reactor may be equal to or more than 10 A and equal to or less than 20 A.

In addition, the input current to the printed circuit board of the power conversion device is 16A or more and 100A or less in all cases.

(6-6)
In the above-mentioned power conversion device 100, a substrate (glass epoxy material) made of a material in which glass cloth is impregnated with epoxy resin is used as the substrate of the printed circuit board 71. The printed circuit board 71 is a substrate having general heat resistance that conforms to the NEMA standard of FR-4.

Instead of this printed circuit board 71, a printed circuit board with a base material made of a glass composite made by layering cut glass fibers and impregnating them with epoxy resin may be used in the power conversion device. For example, even if a power conversion device uses a glass composite board that meets the NEMA standard CEM-3, the manufacturing costs can be reduced.

(6-7)
Although the embodiments of the present disclosure have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the present disclosure described in the claims.

71 Printed circuit board (circuit board)
100 Power conversion device 110 Converter circuit (power conversion circuit)
121 Reactor 130 Inverter circuit (power conversion circuit)
201 Reactor core 202 Reactor winding 203 Reactor terminal (connection part)

JP 2018-148629 A

Claims (8)

A power conversion circuit (110, 130) having a power semiconductor;
A reactor (121) having a core (201) and a winding (202);
A substrate (71);
Equipped with
the power conversion circuit and the reactor are mounted on the same substrate,
The substrate has a base material and a copper foil bonded to the base material,
The substrate is a glass epoxy or a glass composite,
Among the windings, the wire (202a) wound around the core is a wire made of a material having an electrical resistivity (Ω·m) at 20° C. higher than that of copper, and is an aluminum wire.
A power conversion device (100). The reactor further has a connection portion connected to the power conversion circuit,
The connection portion is made of copper.
The power conversion device according to claim 1 . The reactor further has a connection portion (203) connected to the power conversion circuit,
The connection portion is made of plated aluminum.
The power conversion device according to claim 1 . The inductance of the reactor is 1 mH or less at a rated current.
The power conversion device according to claim 1 . A current of 10 A or more flows through the reactor.
5. The power conversion device according to claim 1. A current of 100 A or less flows through the reactor.
The power conversion device according to claim 5 . The substrate has a base material and a copper foil bonded to the base material,
The thickness of the copper foil is 30 μm or more and 75 μm or less.
The power conversion device according to claim 1 . The power supply voltage is single-phase or three-phase, and is 200V or more and 240V or less.
The power conversion device according to any one of claims 1 to 7 .