JP7680685B2 - Electrical equipment, air conditioners - Google Patents

Description

This disclosure relates to electrical devices, etc.

Common-mode voltages resulting from the switching operation of switching devices can cause common-mode noise currents (hereinafter referred to as "common-mode currents") to flow through the ground of the housing or other components to the power supply, potentially resulting in increased radiated noise.

In response to this, for example, a technique is known in which a capacitor (ground capacitor or bypass capacitor) is placed in a bypass path connecting the ground side with the power line or signal line, and the common mode current that has flowed to the ground side is returned to the noise source (see Patent Document 1).

Patent No. 5433987

However, for example, when the switching frequency of a switching device is high, the parasitic inductance component of the capacitor's lead wires has a large effect in the high frequency band where radiated noise is a problem, and the impedance of the bypass path increases. This makes it difficult for high-frequency common mode current to return to the bypass path, and the outflow of common mode current to the power supply cannot be sufficiently suppressed, which may increase radiated noise.

The present disclosure aims to provide a technology that can more appropriately suppress the outflow of common mode current to the power supply side.

In a first aspect of the present disclosure,
a noise filter including a common mode choke coil, the other end of which is electrically connected to the switching device;
a first wiring portion connected to one end side of the common mode choke coil;
a second wiring portion connected to the other end side of the common mode choke coil;
a conductor member having a surface facing the first wiring portion or the second wiring portion;
a dielectric disposed between the conductor member and one of the first wiring portion and the second wiring portion,
the dielectric body is disposed such that a first surface faces a surface of the conductor member and a second surface opposite to the first surface faces a surface of one of the wiring portions;
An electrical device is provided.

According to this aspect, it is possible to increase the stray capacitance between either the first wiring section or the second wiring section and the conductor member. Therefore, the electric device can return the common mode current that flows into the conductor member due to the common mode voltage caused by the switching operation of the switching device to the switching device, which is a noise source, via the stray capacitance. In addition, since the stray capacitance does not include inductance components such as lead wires, there is no increase in impedance even in the case of high frequencies, and the electric device can sufficiently return the high-frequency common mode current to the switching device via the stray capacitance. Therefore, the electric device can more appropriately suppress the outflow of the common mode current to the power supply side.

In addition, in a second aspect of the present disclosure, based on the first aspect described above,
The dielectric may be arranged so that the first surface and a surface of the conductor member, and the second surface and a surface of either one of the wiring portions are in contact with each other.

In addition, in a third aspect of the present disclosure, based on the first aspect described above,
The dielectric may be arranged such that one of the first surface and a surface of the conductor member, and the second surface and a surface of one of the wiring portions are in contact with each other and adjacent to each other.

In addition, in a fourth aspect of the present disclosure, based on the first aspect described above,
The dielectric may be disposed so that both the first surface and a surface of the conductor member, and the second surface and a surface of either one of the wiring portions are in close proximity to each other.

In addition, in a fifth aspect of the present disclosure, on the premise of any one of the first to fourth aspects described above,
The dielectric may be disposed between the conductive member and the second wiring portion.

In addition, in a sixth aspect of the present disclosure, on the premise of any one of the first to fifth aspects described above,
The dielectric may have a relative dielectric constant of 5 or more in a frequency band of 300 MHz or less.

In addition, in a seventh aspect of the present disclosure, on the premise of any one of the first to sixth aspects described above,
The dielectric material may include silicone resin or urethane.

In addition, in an eighth aspect of the present disclosure, on the premise of any one of the first to seventh aspects described above,
The dielectric material may have shock absorbing properties.

In addition, in a ninth aspect of the present disclosure, on the premise of any one of the first to eighth aspects described above,
The switching device is provided.
the second wiring portion is connected between the other end of the common mode choke coil and the switching device,
The conductor member may be located near the switching device and may have a surface facing either one of the wiring portions.

In addition, in a tenth aspect of the present disclosure, based on the above-mentioned ninth aspect,
The conductive member may include a heat dissipation member thermally coupled to the switching device.

In addition, in an eleventh aspect of the present disclosure, based on the above-mentioned ninth or tenth aspect,
The power supply may include an inverter or converter including the switching device.

In addition, in a twelfth aspect of the present disclosure, on the premise of any one of the ninth to eleventh aspects described above,
a first substrate on which the noise filter is mounted;
The semiconductor device may further comprise a second substrate different from the first substrate, the second substrate having the switching device mounted thereon.

In addition, in a thirteenth aspect of the present disclosure, on the premise of any one of the ninth to twelfth aspects described above,
The switching device may include a switching element formed of a wide bandgap semiconductor.

In addition, in a fourteenth aspect of the present disclosure, on the premise of any one of the ninth to thirteenth aspects described above,
The switching frequency of the switching device may be 20 kHz or greater.

In addition, in a fifteenth aspect of the present disclosure, on the premise of any one of the ninth to fourteenth aspects described above,
The switching speed of the switching device may be 10 nanoseconds or less.

In addition, in a sixteenth aspect of the present disclosure,
The present invention includes an electric device according to any one of the first to fifteenth aspects.
An air conditioner is provided.

According to the above-described embodiment, it is possible to more appropriately suppress the outflow of common mode current to the power supply side.

FIG. 1 is a diagram illustrating an example of a refrigerant circuit of an air conditioner. FIG. 1 is a diagram illustrating a configuration of an example of a power conversion device. FIG. 1 is a diagram illustrating an example of a structure of a power conversion device. FIG. 11 is a diagram showing an equivalent circuit in which a power conversion device according to a comparative example is expressed in a common mode. FIG. 11 is a diagram illustrating an example of the relationship between frequency and impedance of stray capacitance and parasitic inductance. FIG. 1 is a diagram showing an equivalent circuit of an example of a power conversion device expressed in common mode.

The following describes the embodiment with reference to the drawings.

[Overview of Air Conditioner]
An overview of an air conditioner 100 according to this embodiment will be described with reference to FIG.

Figure 1 shows an example of a refrigerant circuit for an air conditioner 100.

As shown in FIG. 1, the air conditioner 100 includes an outdoor unit 110, an indoor unit 120, and refrigerant paths 130 and 140. The air conditioner 100 operates a refrigeration cycle consisting of the outdoor unit 110, the indoor unit 120, and the refrigerant paths 130 and 140, and adjusts the temperature, humidity, etc., of the room in which the indoor unit 120 is installed.

The outdoor unit 110 is placed outside the building whose temperature and other conditions are to be adjusted. The outdoor unit 110 is connected to one end of each of the refrigerant paths 130 and 140, and draws in refrigerant from one of the refrigerant paths 130 and 140 and discharges the refrigerant to the other.

The indoor unit 120 is placed in a room of a building where the temperature, etc., is to be adjusted. The indoor unit 120 is connected to the other end of each of the refrigerant paths 130, 140, and draws in refrigerant from one of the refrigerant paths 130, 140 and discharges the refrigerant to the other.

The refrigerant paths 130, 140 are, for example, constructed of pipes, and connect the outdoor unit 110 and the indoor unit 120 so that the refrigerant can circulate between the outdoor unit 110 and the indoor unit 120.

The outdoor unit 110 includes refrigerant paths L1 to L6, oil paths L7 and L8, a four-way switching valve 111, an accumulator 112, a compressor 113, an oil separator 114, an outdoor heat exchanger 115, an outdoor expansion valve 116, and a fan 117.

The refrigerant paths L1 to L6 are configured, for example, as pipes.

The refrigerant path L1 connects one end of the refrigerant path 130 outside the outdoor unit 110 to the four-way switching valve 111.

Refrigerant path L2 connects between the four-way switching valve 111 and the inlet of the compressor 113. Refrigerant path L2 includes refrigerant paths L21 and L22.

Refrigerant path L21 connects between the four-way switching valve 111 and the accumulator 112. Refrigerant path L22 connects between the accumulator 112 and the inlet of the compressor 113.

Refrigerant path L3 connects between the four-way switching valve 111 and the outlet of the compressor 113. Refrigerant path L3 includes refrigerant paths L31 and L32.

Refrigerant path L31 connects the outlet of compressor 113 to oil separator 114. Refrigerant path L32 connects four-way switching valve 111 to oil separator 114.

Refrigerant path L4 connects the four-way switching valve 111 and the outdoor heat exchanger 115.

Refrigerant path L5 connects the outdoor heat exchanger 115 and the outdoor expansion valve 116.

Refrigerant path L6 connects one end of the refrigerant path 140 outside the outdoor unit 110 to the outdoor expansion valve 116.

The oil path L7 is configured, for example, as a pipe line, and is used to allow the oil separated by the oil separator 114 to flow into the refrigerant path L22 and return it to the compressor 113 through the refrigerant path L22.

The oil passing through the oil path L7 may contain, for example, liquid-phase refrigerant (hereinafter, "liquid refrigerant"). In other words, not only oil but also liquid refrigerant flows through the oil path L7.

The oil path L8 is configured, for example, as a pipe line, and is used to allow the oil containing the liquid refrigerant separated by the accumulator 112 to flow into the refrigerant path L22 and return it to the compressor 113 through the refrigerant path L22.

The four-way switching valve 111 reverses the flow of the refrigerant when the air conditioner 100 is in cooling operation and when it is in heating operation.

When the air conditioner 100 is in cooling operation, the four-way switching valve 111 connects the paths indicated by the solid lines in FIG. 1. Specifically, when the air conditioner 100 is in cooling operation, the four-way switching valve 111 connects between the refrigerant path L1 and the refrigerant path L2, and between the refrigerant path L3 and the refrigerant path L4.

On the other hand, when the air conditioner 100 is in heating operation, the four-way switching valve 111 connects the paths indicated by the dotted lines in FIG. 1. Specifically, when the air conditioner 100 is in heating operation, the four-way switching valve 111 connects between the refrigerant path L4 and the refrigerant path L2, and between the refrigerant path L1 and the refrigerant path L3.

The accumulator 112 separates the liquid refrigerant contained in the refrigerant sucked from the refrigerant path L21, and discharges the refrigerant from which some or all of the liquid refrigerant has been removed to the refrigerant path L22. The liquid refrigerant separated by the accumulator 112 contains oil. The accumulator 112 is provided with an oil discharge port connected to the oil path L8, and the oil containing the separated refrigerant flows out through the oil discharge port into the oil path L8 and is returned to the compressor 113 through the oil path L8 and the refrigerant path L22.

The compressor 113 draws in refrigerant from the refrigerant path L22, compresses it to high pressure, and discharges it into the refrigerant path L31.

During cooling operation of the air conditioner 100, the high-temperature, high-pressure refrigerant compressed by the compressor 113 flows into the outdoor heat exchanger 115 through refrigerant paths L3 and L4.

On the other hand, when the air conditioner 100 is in heating operation, the high-temperature, high-pressure refrigerant compressed by the compressor 113 flows through the refrigerant path L3 and the refrigerant path L1 into the refrigerant path 130 outside the outdoor unit 110. The high-temperature, high-pressure refrigerant then flows into the indoor unit 120 through the refrigerant path 130.

The oil separator 114 separates oil from the refrigerant flowing in from the refrigerant path L31, and discharges the refrigerant after some or all of the oil has been separated and removed into the refrigerant path L32. The oil separator 114 is also provided with an oil outlet connected to the oil path L7, and the oil separated from the refrigerant flows out through the oil outlet into the oil path L7 and is returned to the compressor 113 through the oil path L7 and the refrigerant path L22.

The outdoor heat exchanger 115 exchanges heat between the outside air and the refrigerant passing through the interior. Specifically, the outdoor heat exchanger 115 is provided with a fan 117, and the outdoor heat exchanger 115 exchanges heat between the outside air blown by the fan 117 and the refrigerant flowing through the interior.

During cooling operation of the air conditioner 100, the outdoor heat exchanger 115 causes the high-temperature, high-pressure refrigerant compressed by the compressor 113, which flows in from the refrigerant path L4, to dissipate heat to the outside air, and causes the condensed and liquefied refrigerant (liquid refrigerant) to flow into the refrigerant path L5.

In addition, when the air conditioner 100 is in heating operation, the outdoor heat exchanger 115 causes the low-temperature, low-pressure liquid refrigerant flowing in from the refrigerant path L5 to absorb heat from the outside air, and causes the evaporated refrigerant to flow into the refrigerant path L4.

When the air conditioner 100 is in heating operation, the outdoor expansion valve 116 is closed to a predetermined opening degree, and reduces the pressure of the refrigerant (liquid refrigerant) flowing in from the refrigerant path L6 to a predetermined pressure. On the other hand, when the air conditioner 100 is in cooling operation, the outdoor expansion valve 116 is fully open, and passes the refrigerant (liquid refrigerant) from the refrigerant path L5 to the refrigerant path L6. The outdoor expansion valve 116 is, for example, a solenoid valve.

The indoor unit 120 includes an indoor expansion valve 121, an indoor heat exchanger 122, and a fan 123.

When the air conditioner 100 is in cooling operation, the indoor expansion valve 121 is closed to a predetermined opening degree, and reduces the pressure of the supercooled liquid refrigerant flowing in from the refrigerant path 140 to a predetermined pressure. On the other hand, when the air conditioner 100 is in heating operation, the indoor expansion valve 121 is fully open, and allows the refrigerant (liquid refrigerant) flowing out from the indoor heat exchanger 122 to pass toward the refrigerant path 140. The indoor expansion valve 121 is, for example, a solenoid valve.

The indoor heat exchanger 122 exchanges heat between the indoor air and the refrigerant passing through it. Specifically, the indoor air passes around the indoor heat exchanger 122 by the action of the fan 123 mounted in the indoor unit 120, promoting heat exchange with the refrigerant inside the indoor heat exchanger 122. Then, the indoor air that has exchanged heat with the refrigerant inside the indoor heat exchanger 122 is sent out of the indoor unit 120 by the action of the fan 123, thereby realizing cooling or heating of the room.

When the air conditioner 100 is in cooling operation, the indoor heat exchanger 122 absorbs heat from the indoor air into the low-temperature, low-pressure liquid refrigerant decompressed by the indoor expansion valve 121, lowering the temperature of the indoor air.

On the other hand, when the air conditioner 100 is in heating operation, the indoor heat exchanger 122 causes the high-temperature, high-pressure refrigerant flowing in from the outdoor unit 110 through the refrigerant path 130 to dissipate heat into the indoor air, thereby raising the temperature of the indoor air.

[Configuration of power conversion device]
Next, the configuration of the power conversion device 200 mounted on the air conditioner 100 according to this embodiment will be described with reference to Figs. 2 and 3.

Figure 2 is a diagram showing an example of the configuration of a power conversion device 200. Figure 3 is a diagram showing an example of the structure of a power conversion device 200.

In addition, in Figure 3, only the housing 110H is depicted as a cross-sectional view for convenience.

As shown in FIG. 2, the outdoor unit 110 has a housing 110H that houses its components, and includes a power conversion device 200 housed in the housing 110H.

The power conversion device 200 drives the electric motor 113M of the compressor 113 using three-phase AC power from the commercial power source PS supplied from outside the outdoor unit 110.

The power conversion device 200 includes a terminal T_FG, a power line L_R, a power line L_S, a power line L_T, a power terminal block 210, a noise filter 220, an inverter 230, a heat dissipation section 240, and a dielectric 250.

Terminal T_FG is provided on housing 110H and is grounded outside housing 110H. As a result, housing 110H is considered to be a reference potential part equivalent to ground.

The power supply lines L_R, L_S, and L_T supply three-phase AC from the commercial power supply PS to the inverter 230.

The power supply line L_R supplies R-phase AC from the commercial power supply PS to the inverter 230. The power supply line L_R includes power supply lines L_R1 to L_R5.

The power supply line L_S supplies S-phase AC from the commercial power supply PS to the inverter 230. The power supply line L_S includes power supply lines L_S1 to L_S5.

The power supply line L_T supplies T-phase AC from the commercial power supply PS to the inverter 230. The power supply line L_T includes power supply lines L_T1 to L_T5.

The power lines L_R1, L_S1, and L_T1 each connect between the commercial power supply PS and the power terminal block 210. The power lines L_R2, L_S2, and L_T2 each connect between the power terminal block 210 and one end of the power lines L_R3, L_S3, and L_T3 of the noise filter 220. The power lines L_R3, L_S3, and L_T3, and the power lines L_R4, L_S4, and L_T4 correspond to the power lines inside the noise filter 220. For example, as shown in FIG. 3, the power lines L_R3, L_S3, and L_T3, and the power lines L_R4, L_S4, and L_T4 are implemented as wiring patterns on the board 220PB. Power supply lines L_R5, L_S5, and L_T5 respectively connect the other ends of power supply lines L_R4, L_S4, and L_T4 of noise filter 220 to inverter 230.

The power supply terminal block 210 relays and branches the three-phase AC supplied by the power supply lines L_R1, L_S1, and L_T1 to various devices.

One end of the power line L_R1 and one end of the power line L_R2 are connected to the power terminal block 210, electrically connecting the power lines L_R1 and L_R2. Similarly, one end of the power line L_S1 and one end of the power line L_S2 are connected to the power terminal block 210, electrically connecting the power lines L_S1 and L_S2. Similarly, one end of the power line L_T1 and one end of the power line L_T2 are connected to the power terminal block 210, electrically connecting the power lines L_T1 and L_T2.

The noise filter 220 suppresses noise in the current of the power conversion device 200. For example, as shown in Figures 2 and 3, the noise filter 220 includes a common mode choke coil 221 and a Y capacitor 222, and is mounted on the substrate 220PB.

The common mode choke coil 221 acts as an inductor to suppress the common mode noise currents flowing through the power lines L_R3, L_S3, and L_T3, and the power lines L_R4, L_S4, and L_T4.

The Y capacitor 222 serves to return the common mode current that has flowed out to ground to the noise source (inverter 230). The Y capacitor 222 includes Y capacitors 222R, 222S, and 222T.

The Y capacitor 222R is provided in a bypass path connecting the power line L_R4 and the housing 110H corresponding to ground. The Y capacitor 222S is provided in a bypass path connecting the power line L_S4 and the housing 110H corresponding to ground. The Y capacitor 222T is provided in a bypass path connecting the power line L_T4 and the housing 110H corresponding to ground. For example, as shown in FIG. 3, the Y capacitor 222 and the housing 110H are connected by a lead wire 225.

The inverter 230 generates a three-phase AC of a predetermined voltage and frequency using the three-phase AC supplied through the power lines L_R, L_S, and L_T, and outputs it to the electric motor 113M. This allows the power conversion device 200 to drive the compressor 113. For example, as shown in FIG. 3, the inverter 230 is mounted on a board 230PB separate from the board 220PB on which the noise filter 220 is mounted. The inverter 230 includes a rectifier circuit 231, a smoothing circuit 232, and an inverter circuit 233.

The rectifier circuit 231 converts the three-phase AC of the power supply lines L_R5, L_S5, and L_T5 into DC and outputs it to the power supply lines L_P1 and L_N1. For example, as shown in FIG. 2, the rectifier circuit 231 includes a power device 231PD. The power device 231PD is a semiconductor rectifier diode.

The smoothing circuit 232 smoothes the direct current of the power supply lines L_P1 and L_N1. For example, the smoothing circuit 232 includes a smoothing capacitor 232C and a reactor 232L.

The smoothing capacitor 232C is provided in the path connecting the power supply lines L_P1 and L_N1. The smoothing capacitor 232C smoothes the direct current output from the rectifier circuit 231 and the direct current output (regenerated) from the inverter circuit 233 while repeatedly charging and discharging as appropriate.

The reactor 232L is provided on the power supply line L_P1. For example, the reactor 232L is provided on the power supply line L_P1 between the rectifier circuit 231 and the smoothing capacitor 232C. The reactor 232L smoothes the direct current output from the rectifier circuit 231 and the direct current output (regenerated) from the inverter circuit 233 while generating a voltage to appropriately prevent changes in the current.

The inverter circuit 233 is connected to the other end of the power supply lines L_P1 and L_N1. The inverter circuit 233 includes a power device 233PD. The power device 233PD is, for example, a semiconductor switch. The semiconductor switch is, for example, an insulated gate bipolar transistor (IGBT), a metal-oxide-semiconductor field-effect transistor (MOSFET), or a high electron mobility transistor (HEMT). The semiconductor switch is, for example, mainly made of silicon (Si). The semiconductor switch may also be mainly made of a wide band gap semiconductor material. The power device 233PD may also include, in addition to the semiconductor switch, a semiconductor freewheel diode connected in parallel with the semiconductor switch.

The inverter circuit 233 converts the direct current output from the smoothing circuit 232 into three-phase alternating current (i.e., U-phase, V-phase, and W-phase alternating current) having a predetermined frequency and a predetermined voltage by the switching operation of the power device 233PD, and outputs it to the electric motor 113M. The power device 233PD may have a relatively high switching speed. For example, the switching speed of the power device 233PD (i.e., the time required for switching) is 10 nanoseconds or less. The switching frequency of the power device 233PD is set to, for example, 20 kHz (kilohertz) or more. This makes it possible to remove the frequency of noise caused by the switching operation of the power device 233PD from the human audible range.

The heat dissipation section 240 dissipates heat from the power device 233PD to the outside of the power device 233PD.

For example, as shown in FIG. 3, the heat dissipation unit 240 is a heat sink and is connected to the outer surface of the housing 110H. A through hole 110Ha is provided at a location of the housing 110H facing the power device 233PD, and the power device 233PD and the heat dissipation unit 240 (heat sink) are thermally coupled to enable thermal conduction through the through hole 110Ha.

The power device 233PD and the heat dissipation section 240 (heat sink) are in indirect contact with each other, for example, via a heat dissipation promotion member that is an insulator, so that heat conduction is possible. The heat dissipation promotion member is, for example, a heat conductive sheet containing a heat conductive filler, heat conductive grease, etc. Also, the power device 233PD and the heat dissipation section 240 (heat sink) may be in direct contact with each other, so that heat conduction is possible.

The heat dissipation section 240 may also be a water jacket through which a refrigerant flows.

Hereinafter, the housing 110H and the heat dissipation section 240 may be collectively referred to as the "conductor section 260."

The dielectric 250 is disposed between the housing 110H and each of the power lines L_R4, L_S4, and L_T4 at the locations where the housing 110H faces each of the power lines L_R4, L_S4, and L_T4. For example, one dielectric 250 is provided and disposed so as to span the range where the housing 110H faces each of the power lines L_R4, L_S4, and L_T4. Alternatively, three dielectrics 250 may be provided and disposed at each location where the housing 110H faces each of the power lines L_R4, L_S4, and L_T4.

Specifically, as shown in FIG. 3, dielectric 250 is arranged so that surface 250s1 faces inner surface 110Hs of housing 110H, and surface 250s2 faces surfaces WPs1, WPs2, and WPs3 of the wiring pattern corresponding to power lines L_R4, L_S4, and L_T4. As a result, as shown in FIG. 2, dielectric 250 can increase stray capacitances Cs_R, Cs_S, and Cs_T between housing 110H and each of power lines L_R4, L_S4, and L_T4, which are arranged to face each other. Hereinafter, the combined capacitance of stray capacitances Cs_R, Cs_S, and Cs_T is referred to as "stray capacitance Cs0."

The positional relationship between the dielectric 250 and the housing 110H in the opposing direction may be any as long as it is possible to increase the stray capacitance Cs0 to an appropriate level. For example, as shown in FIG. 3, the dielectric 250 has a surface 250s1 in direct contact with the inner surface 110Hs of the housing 110H, and one end on the surface 250s1 side is supported by the housing 110H. The dielectric 250 may also be disposed so that there is a minute gap between the surface 250s1 and the inner surface 110Hs of the housing 110H, and the surface 250s1 and the inner surface 110Hs of the housing 110H are close to each other. The minute gap is, for example, a gap of 1 mm or less.

Similarly, the positional relationship between the dielectric 250 and the power lines L_R4, L_S4, and L_T4 in the opposing direction may be any as long as it is possible to increase the stray capacitance Cs0 to an appropriate level. For example, as shown in FIG. 3, when viewed from the inner surface 110Hs of the housing 110H, a wiring pattern corresponding to the power lines L_R4, L_S4, and L_T4 is mounted on the back surface of the substrate 220PB, the surface 250s2 of the dielectric 250 abuts against the surface of the substrate 220PB. As a result, the other end of the dielectric 250 on the surface 250s2 side is supported by the substrate 220PB, and the surface 250s2 can face the surfaces WPs1, WPs2, and WPs3 of the wiring pattern corresponding to the power lines L_R4, L_S4, and L_T4 via the substrate 220PB. Also, in this case, the surface 250s2 of the dielectric 250 and the substrate 220PB may be arranged so that they are close to each other with a small gap between them. Also, when a wiring pattern corresponding to the power lines L_R4, L_S4, and L_T4 is mounted on the surface of the substrate 220PB as viewed from the inner surface 110Hs of the housing 110H, the surface 250s2 of the dielectric 250 may be in direct contact with the surfaces WPs1, WPs2, and WPs3 of the wiring pattern. Also, in this case, the dielectric 250 may be arranged so that the surface 250s2 and the surfaces WPs1, WPs2, and WPs3 of the wiring pattern are close to each other with a small gap between them.

If there is a small gap between the dielectric 250 and either the housing 110H or the substrate 220PB including the power lines L_R4, L_S4, and L_T4, the dielectric 250 may be supported by another support member. For example, a support member is provided that supports the dielectric 250 from a direction perpendicular to the direction in which the substrate 220PB faces the inner surface 110Hs of the housing 110H.

The dielectric 250 has a relative dielectric constant of 5 or more in a frequency band of 300 MHz (megahertz) or less. This allows the floating capacitance Cs0 to be sufficiently increased in a frequency band (30 MHz to 300 MHz) where radiation noise is a problem in various standards related to EMI (Electromagnetic Interference). Specifically, the dielectric 250 includes, for example, silicone resin or urethane. This allows the dielectric 250 to achieve a relatively high floating capacitance Cs0 in a desired frequency band, as well as a relatively high shock absorption. Therefore, for example, the installation workability of the dielectric 250 in the manufacturing process can be improved. In addition, even if a relatively high impact is applied to the board 220PB or the housing 110H, it is possible to suppress a situation in which problems occur in the dielectric 250 or other parts supporting the dielectric 250.

[Common mode current generated in power conversion equipment]
Next, the common mode current generated in the power conversion device 200 according to the present embodiment will be described with reference to FIGS.

Figure 4 is a diagram showing an equivalent circuit of a power conversion device 200com according to a comparative example expressed in common mode. Figure 5 is a diagram showing an example of the relationship between the frequency and the impedance of each of the stray capacitance and the parasitic inductance. Figure 6 is a diagram showing an equivalent circuit of an example of a power conversion device 200 expressed in common mode.

In Figure 5, a logarithmic axis is used to represent frequency.

<Common mode current of power conversion device according to comparative example>
As shown in Figure 4, the power conversion device 200com of the comparative example differs from the power conversion device 200 of the above-mentioned example (Figure 2) in that it does not have a dielectric 250, but is the same as the power conversion device 200 of the above-mentioned example in other respects.

A stray capacitance Cs1 exists between the power device 233PD of the inverter 230 and the heat dissipation section 240. Therefore, a common mode voltage may be generated between the power device 233PD and the heat dissipation section 240 due to the switching operation of the power device 233PD, and a common mode current Ic may flow out to the conductor section 260 through the stray capacitance Cs1.

The power conversion device 200com can return the common mode current Ic_ref1, which corresponds to at least a portion of the common mode current Ic that flows into the conductor section 260, to the inverter 230 through a bypass path in which the Y capacitor 222 is provided.

The bypass path including the Y capacitor 222 has a parasitic inductance component of the lead wire 225 and a parasitic inductance component of the wiring pattern 222WP on the substrate 220PB.

As shown in FIG. 5, the impedance of the parasitic inductance component increases as the current frequency increases. Therefore, for example, when the power device 233PD is driven at a relatively high frequency of 20 kHz or more, the high-frequency common mode current Ic flows out, and it is possible that the common mode current Ic_ref1 cannot be sufficiently drawn into the bypass path with high impedance.

As described above, stray capacitance Cs0 exists between the housing 110H and the power lines L_R4, L_S4, and L_T4, and a path exists for returning the common mode current Ic to the inverter 230 through the stray capacitance Cs0. However, as shown in FIG. 5, when the dielectric 250 does not exist, the impedance of the stray capacitance Cs0 is relatively high. Therefore, even though the impedance of the stray capacitance Cs0 decreases with increasing frequency, it is highly likely that the power conversion device 200com will not be able to return the common mode current Ic to the inverter 230 through the stray capacitance Cs0.

Therefore, as shown in FIG. 4, the power conversion device 200com according to the comparative example may not be able to adequately suppress the outflow of the common mode current Ic_out to the commercial power supply PS.

<Common mode current of power conversion device according to embodiment>
In the power conversion device 200 according to this embodiment, as described above, the dielectric 250 is disposed between the housing 110H and each of the power lines L_R4, L_S4, and L_T4.

This allows the floating capacitance Cs0 to be increased. Therefore, as shown in FIG. 5, the impedance of the floating capacitance Cs0 can be reduced. In addition, since there is no wiring pattern or lead wire in the bypass path through the floating capacitance Cs0, there is no increase in impedance due to parasitic inductance. As a result, the power conversion device 200 can return the common mode current Ic_ref2 to the inverter 230 through the floating capacitance Cs0 in addition to the bypass path including the Y capacitor 222. In particular, in the bypass path through the floating capacitance Cs0, the impedance of the floating capacitance Cs0 decreases with an increase in frequency, and there is no increase in impedance with an increase in frequency due to the parasitic inductance component. Therefore, even if the high-frequency common mode current Ic flows out to the conductor portion 260, the power conversion device 200 can sufficiently return the high-frequency common mode current Ic_ref2 to the inverter 230 through the floating capacitance Cs0.

Therefore, as shown in FIG. 6, the power conversion device 200 can more appropriately suppress the outflow of the common mode current Ic_out to the commercial power supply PS.

[Other embodiments]
Next, another embodiment will be described.

The above-described embodiments may be modified or altered as appropriate.

For example, in the above embodiment, the dielectric 250 may be provided between the inner surface 110Hs of the housing 110H and the power lines L_R3, L_S3, and L_T3, instead of between the inner surface 110Hs of the housing 110H and the power lines L_R4, L_S4, and L_T4.

In the above embodiment, the dielectric 250 may be arranged so that the surface 250s2 faces the surface of the wiring pattern of the power lines L_P1 and L_N1 mounted on the substrate 230PB, instead of the surfaces WPs1, WPs2, and WPs3 of the wiring pattern. In this case, the surface 250s2 of the dielectric 250 may be in direct contact with the opposing surfaces of the power lines L_P1 and L_N1, or may be arranged in close proximity to the opposing surfaces of the power lines L_P1 and L_N1 with a small gap. This allows the power conversion device 200 to bypass the common mode current at a location closer to the power device 233PD, which is a noise source. Therefore, the power conversion device 200 can more appropriately suppress the radiation noise caused by the common mode current.

In addition, in the above-mentioned embodiment and its modified and altered examples, the dielectric 250 may be arranged so that the surface 250s1 faces the surface of the heat dissipation unit 240 instead of the inner surface 110Hs of the housing 110H. In this case, the surface 250s1 of the dielectric 250 may be in direct contact with the facing surface of the heat dissipation unit 240, or may be arranged in close proximity to the facing surface of the heat dissipation unit 240 with a small gap therebetween. This allows the power conversion device 200 to bypass the common mode current at a location closer to the power device 233PD, which is the noise source. Therefore, the radiation noise caused by the common mode current can be more appropriately suppressed.

In addition, in the above-described embodiment and its modified and altered examples, the housing 110H and the power device 233PD may be arranged in such a manner that a common mode current can flow out without passing through the heat dissipation section 240. Specifically, the housing 110H only needs to be located close enough to the power device 233PD that a common mode current can flow out through stray capacitance. The proximity of the power device 233PD is, for example, a distance equivalent to the thickness of a heat dissipation promotion member (e.g., a heat dissipation sheet) when the power device 233PD and the heat dissipation section 240 are in indirect contact with each other.

In addition, in the above-described embodiment and its modified and altered examples, the power conversion device 200 may supply power to the motor of the fan 117 instead of or in addition to the motor 113M of the compressor 113 to drive it.

In addition, in the above-described embodiment and its variations and modifications, the noise filter 220 and the inverter 230 may be mounted on the same board.

In addition, in the above-described embodiment and its modified and altered examples, at least one of the smoothing capacitor 232C and the reactor 232L may be omitted, or the smoothing circuit 232 itself may be omitted.

In the above-described embodiment and its modified and altered examples, the commercial power source PS may supply single-phase AC to the power conversion device 200 instead of three-phase AC. In this case, the power lines L_R, L_S, and L_T are replaced with two power lines. In this case, the common mode choke coil 221 is replaced with a single-phase common mode choke coil, and the Y capacitor 222 is replaced with two Y capacitors that bypass each of the two power lines and the housing 110H. In this case, the dielectric 250 is installed between the inner surface 110Hs of the housing 110H and the two power lines on the front side or the two power lines on the rear side of the single-phase common mode choke coil.

In the above-described embodiment and its modified and altered examples, the power device 231PD of the rectifier circuit 231 may be a semiconductor switch. In this case, the switching operation of the power device 231PD causes a common mode current to flow into the housing 110H through the stray capacitance between the power device 231PD and the housing 110H. For example, a heat dissipation section that is thermally coupled to the power device 231PD is provided, similar to the heat dissipation section 240 for the power device 233PD, and the heat dissipation section is connected in a manner that directly contacts the housing 110H. As a result, a common mode voltage is applied to the stray capacitance between the power device 231PD and the heat dissipation section, and a common mode current flows into the housing 110H through the heat dissipation section. Therefore, the power conversion device 200 can more appropriately suppress the common mode current that causes the power device 231PD of the rectifier circuit 231 to be a noise source, due to the action of the dielectric 250.

The power conversion device 200 of the above-described embodiment may be installed in a refrigeration unit other than the air conditioner 100. In other words, the power conversion device 200 of the above-described embodiment may be installed in any device having a refrigeration cycle.

The power conversion device 200 of the above-described embodiment may be mounted on a device other than a refrigerator to drive an electric motor or the like mounted on that device. For example, the power conversion device 200 of the above-described embodiment may be mounted on a vehicle to drive an electric motor or the like of the vehicle.

[Effect]
Next, the operation of the electrical device and the air conditioner according to this embodiment will be described.

In this embodiment, the electric device includes a noise filter, a first wiring section, a second wiring section, a conductor member, and a dielectric. The electric device is, for example, the power conversion device 200 described above. The noise filter is, for example, the noise filter 220 described above. The first wiring section is, for example, the power lines L_R3, L_S3, and L_T3 described above. The second wiring section is, for example, the power lines L_R4, L_S4, and L_T4 described above. The conductor member is, for example, the conductor section 260 described above. The dielectric is, for example, the dielectric 250 described above. Specifically, the noise filter includes a common mode choke coil, and the other end of the one end side and the other end side is electrically connected to the switching device. The common mode choke coil is, for example, the common mode choke coil 221 described above. The switching device is, for example, the power device 233PD described above. In addition, the first wiring section is connected to one end side of the common mode choke coil. The second wiring portion is connected to the other end of the common mode choke coil. The conductor member has a surface facing the first wiring portion or the second wiring portion. The dielectric is disposed between the conductor member and either one of the first wiring portion or the second wiring portion. The dielectric is disposed such that the first surface faces the surface of the conductor member, and the second surface opposite the first surface faces the surface of either one of the first wiring portion or the second wiring portion. The first surface and the second surface of the dielectric are, for example, the above-mentioned surfaces 250s1 and 250s2. The surface of the conductor member is, for example, the above-mentioned inner surface 110Hs. The surface of either one of the first wiring portion or the second wiring portion is, for example, the above-mentioned surfaces WPs1, WPs2, and WPs3.

This makes it possible to increase the stray capacitance between either the first wiring section or the second wiring section and the conductor member. Therefore, the electric device can return the common mode current that flows into the conductor member due to the common mode voltage caused by the switching operation of the switching device to the switching device, which is a noise source, via the stray capacitance. Furthermore, since the stray capacitance does not include inductance components such as lead wires, impedance does not increase even in the case of high frequencies, and the electric device can sufficiently return the high-frequency common mode current to the switching device via the stray capacitance. Therefore, the electric device can more appropriately suppress the outflow of the common mode current to the power supply side.

In addition, in this embodiment, the dielectric may be arranged so that both the first surface and the surface of the conductor member, and the second surface and the surface of either one of the wiring portions are in contact.

This allows the dielectric to increase the stray capacitance between either the first wiring section or the second wiring section and the conductor member.

In addition, in this embodiment, the dielectric may be arranged so that either the first surface and the surface of the conductor member, or the second surface and the surface of one of the wiring parts are in contact with each other and are adjacent to each other.

This makes it possible to increase the stray capacitance between either the first wiring section or the second wiring section and the conductor member.

In addition, in this embodiment, the dielectric may be arranged so that both the first surface and the surface of the conductor member, and the second surface and the surface of either one of the wiring portions are in close proximity.

This makes it possible to increase the stray capacitance between either the first wiring section or the second wiring section and the conductor member.

In addition, in this embodiment, the dielectric may be disposed between the conductor member and the second wiring portion.

This allows the common mode current to be bypassed to the second wiring section, which is closer to the switching device, which is the noise source, out of the first wiring section and the second wiring section. This makes it possible to more appropriately suppress the radiation noise caused by the common mode current.

In addition, in this embodiment, the dielectric may have a relative dielectric constant of 5 or more in a frequency band of 300 MHz or less.

This makes it possible to sufficiently increase the stray capacitance between either the first wiring section or the second wiring section and the conductor member in the frequency band (30 MHz to 300 MHz) where radiation noise is a problem in various EMI standards. As a result, the electrical device can properly return the common mode current that has flowed into the conductor member through the stray capacitance from the switching device, which is the noise source.

In addition, in this embodiment, the dielectric material may include silicone resin or urethane.

This allows the dielectric constant of the dielectric to be set relatively large, and the stray capacitance between either the first wiring section or the second wiring section and the conductor member to be sufficiently increased.

In this embodiment, the dielectric may also have shock absorbing properties.

This can improve the workability of installing the dielectric during the manufacturing process, for example. In addition, the electrical device can prevent problems from occurring in the dielectric or other components connected to the dielectric, even if an impact is applied to the board or conductor member on which the first wiring section and the second wiring section are mounted.

In this embodiment, the electric device may include the above-mentioned switching device. The second wiring portion may be connected between the other end of the common mode choke coil and the switching device. The conductor member may be located near the switching device and have a surface facing either the first wiring portion or the second wiring portion.

This allows the electrical device to more appropriately suppress the outflow of common-mode current flowing into the conductor member due to the common-mode voltage caused by the switching operation of the switching device to the power supply side.

In addition, in this embodiment, the conductor member may include a heat dissipation member thermally coupled to the switching device. The heat dissipation member is, for example, the heat dissipation section 240 described above.

This allows the electrical device to more appropriately prevent the common mode current that flows into the conductor member via the heat dissipation member from flowing out to the power supply side.

In addition, this embodiment may include an inverter or converter including a switching device. The inverter is, for example, the inverter circuit 233 described above. The converter is, for example, the rectifier circuit 231 described above.

This allows the electrical device to more appropriately suppress the outflow of common-mode current flowing into the conductor member due to the common-mode voltage caused by the switching operation of the inverter or converter switching device to the power supply side.

In this embodiment, the electrical device may also include a first substrate on which a noise filter is mounted, and a second substrate different from the first substrate on which a switching device is mounted.

This allows the electrical device to bypass the common mode current flowing from the switching device of the second substrate to the conductor member to the first wiring section or the second wiring section of the first substrate by means of stray capacitance.

In addition, in this embodiment, the switching device may include a switching element formed of a wide bandgap semiconductor.

This allows the electrical device to more appropriately suppress the common mode current that flows from a switching device, including a switching element formed from a wide bandgap semiconductor, to a conductor member from flowing out to the power supply side.

In addition, in this embodiment, the switching frequency of the switching device may be 20 kHz or more.

As a result, the electrical device can more appropriately suppress the outflow of common mode current to the power supply side, even when the switching frequency of the switching device is relatively high at 20 kHz and high-frequency common mode current flows into the conductor member.

In addition, in this embodiment, the switching speed of the switching device may be 10 nanoseconds or less.

As a result, the electrical device can more appropriately suppress the common mode current from flowing to the power supply side, even when the switching speed of the switching device is relatively high at 10 nanoseconds or less and high-frequency common mode current flows into the conductor member.

In addition, in this embodiment, the air conditioner may be equipped with the above-mentioned electrical device. The air conditioner is, for example, the air conditioner 100 described above.

This allows the electrical device to suppress noise radiation outside the air conditioner.

Although the embodiments have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims.

100 Air conditioner 110 Outdoor unit 110H Housing 110Hs Inner surface 113 Compressor 113M Motor 120 Indoor unit 130 Refrigerant path 140 Refrigerant path 200 Power conversion device 210 Power terminal block 220 Noise filter 220PB Substrate 221 Common mode choke coil 222 Y capacitor 222R, 222S, 222T Y capacitor 222WP Wiring pattern 225 Lead wire 230 Inverter 230PB Substrate 231 Rectifier circuit 232 Smoothing circuit 233 Inverter circuit 233PD Power device 240 Heat dissipation section 250 Dielectric 250s1, 250s2 Surface 260 Conductor section Cs_R, Cs_S, Cs_T Stray capacitance Cs0, Cs1 Stray capacitance L_N1 Power line L_P1 Power line L_R Power line L_R1 to L_R5 Power line L_S Power line L_S1 to L_S5 Power line L_T Power line L_T1 to L_T5 Power line PS Commercial power supply WPs1, WPs2, WPs3

Claims (16)

a noise filter including a common mode choke coil, the other end of which is electrically connected to the switching device;
a first wiring portion connected to one end side of the common mode choke coil;
a second wiring portion connected to the other end side of the common mode choke coil;
a conductor member having a surface facing the first wiring portion or the second wiring portion;
a Y capacitor provided in a path electrically connecting the second wiring portion and the conductor member;
a dielectric provided separately from the Y capacitor and disposed between the conductor member and one of the first wiring portion and the second wiring portion,
the dielectric body is disposed such that a first surface faces a surface of the conductor member and a second surface opposite to the first surface faces a surface of one of the wiring portions;
Electrical equipment. the dielectric body is disposed so that the first surface and a surface of the conductor member, and the second surface and a surface of either one of the wiring portions are in contact with each other;
10. The electrical device of claim 1. the dielectric is arranged such that one of the first surface and a surface of the conductor member, and the second surface and a surface of either one of the wiring portions are in contact with each other and are adjacent to each other;
10. The electrical device of claim 1. the dielectric body is disposed so that the first surface and a surface of the conductor member, and the second surface and a surface of either one of the wiring portions are in close proximity to each other;
10. The electrical device of claim 1. The dielectric is disposed between the conductor member and the second wiring portion.
5. An electrical device according to any one of the preceding claims. The dielectric has a relative dielectric constant of 5 or more in a frequency band of 300 MHz or less.
5. An electrical device according to any one of the preceding claims. The material of the dielectric material includes silicone resin or urethane.
5. An electrical device according to any one of the preceding claims. The dielectric has shock absorbing properties.
5. An electrical device according to any one of the preceding claims. A switching device is provided.
the second wiring portion is connected between the other end of the common mode choke coil and the switching device,
the conductor member is located near the switching device and has a surface facing one of the wiring portions;
5. An electrical device according to any one of the preceding claims. the conductive member includes a heat dissipation member thermally coupled to the switching device;
10. An electrical device according to claim 9. an inverter or converter including the switching device;
10. An electrical device according to claim 9. a first substrate on which the noise filter is mounted;
a second substrate different from the first substrate, the second substrate having the switching device mounted thereon;
10. An electrical device according to claim 9. The switching device includes a switching element formed of a wide band gap semiconductor.
10. An electrical device according to claim 9. The switching frequency of the switching device is 20 kHz or more.
10. An electrical device according to claim 9. The switching speed of the switching device is 10 nanoseconds or less.
10. An electrical device according to claim 9. Equipped with an electrical device according to any one of claims 1 to 4,
Air conditioner.

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