Inverter device

Abstract

[Problem] To provide a compact and low-cost inverter device capable of reducing a plurality of noises having different frequency bands. [Solution] An inverter device 1 comprises: an inverter circuit 11 having a plurality of switching elements Q1-Q6; a filter circuit 12 provided at a power-supply input part of the inverter circuit 11; and a metal housing 13 for housing the inverter circuit and the filter circuit. The filter circuit 12 includes: a common mode coil 12A inserted on power supply lines PL1, PL2 passing through the power-supply input part; and at least one set of a Y capacitor 12B and a resistor 12C connected in series between the housing 13 and a power supply line PL2 that connects the switching element Q2 and the common mode coil 12A. The filter circuit is configured such that noise in the FM band emitted from the inverter circuit 11 passes through a first path including the common mode coil 12A, and noise in the AM band passes through a second path including the Y capacitor 12B and the resistor 12C.

Description

Inverter Device

[0001] The present invention relates to an inverter device that drives devices provided in a vehicle air conditioning system.

[0002] Generally, an inverter device that drives equipment installed in a vehicle air conditioning system includes a power supply switching element. When the switching element of the inverter device switches on and off, harmonics of the operating frequency of the inverter device are radiated as noise into the surrounding area, which can cause noise in a radio receiver or other device installed in the vehicle. Conventional techniques for dealing with such radiated noise from an inverter device include a filter circuit that reduces radiated noise by installing a common mode coil on the power supply line or by installing a Y capacitor between the power supply line and the inverter device housing, which serves as a reference ground (see, for example, Patent Document 1).

[0003] JP 2023-110520 A

[0004] However, noise emitted from such an inverter device may occur across different frequency bands, such as the AM and FM bands. The common mode coils used in conventional filter circuits are effective at reducing noise in relatively low frequency bands, and their noise reduction effect can be enhanced by increasing the number of coil turns. However, as the distance between the windings decreases due to an increase in the number of turns, the parasitic capacitance between the windings increases, making it difficult for the coil to function effectively against noise in relatively high frequency bands (such as the FM band), resulting in a decrease in noise reduction performance. In order to effectively reduce noise across different frequency bands using a common mode coil, multiple separate common mode coils corresponding to each frequency band must be prepared, resulting in issues such as increased size and cost.

[0005] Furthermore, with the Y capacitors used in conventional filter circuits, noise across different frequency bands propagating along the inverter's power lines passes through the Y capacitor and leaks out to the inverter's housing (reference ground). The housing may be electrically connected to the shielded wire of the power harness via a connector or other device. In this case, noise leaking into the inverter's housing may return to the power lines within the power harness due to stray capacitance between the power lines and the shielded wire within the power harness. This tendency is particularly pronounced for noise in relatively high frequency bands. Therefore, while relatively low-frequency noise across different frequency bands can be diverted to ground by the Y capacitor, relatively high-frequency noise is likely to travel through the inverter's housing and return to the power lines via the shielded wire of the power harness. High-frequency noise propagating along such a feedback path does not pass through the common-mode coil and is therefore radiated outside the inverter without being attenuated (choke), potentially contributing to a deterioration in noise levels.

[0006] The present invention has been made in view of the above points, and has as its object to provide a small-sized, low-cost inverter device that can reduce a plurality of noises in different frequency bands.

[0007] To achieve the above object, one aspect of the present invention provides an inverter device for driving equipment included in a vehicle air conditioning system. The inverter device includes an inverter circuit having a plurality of switching elements, a filter circuit provided at a power input section of the inverter circuit, and a metal housing that houses at least the inverter circuit and the filter circuit. The filter circuit includes a common-mode coil inserted in a power line passing through the power input section of the inverter circuit, and at least one set of a Y capacitor and a resistor connected in series between the power line connecting the switching elements and the common-mode coil and the housing, so that, of multiple noises of different frequency bands emitted from the inverter circuit, noise in a relatively high frequency band passes through a first path including the common-mode coil, and noise in a relatively low frequency band passes through a second path including the Y capacitor and the resistor.

[0008] According to one aspect of the present invention as described above, it is possible to provide a small-sized, low-cost inverter device that can reduce a plurality of noises in different frequency bands.

[0009] Fig. 1 is a diagram showing a schematic configuration of an electric compressor to which an inverter device according to one embodiment of the present invention is applied. Fig. 2 is a circuit diagram showing an example configuration of the inverter device according to the embodiment. Fig. 3 is a diagram explaining noise propagation paths in the inverter device of Fig. 2. Fig. 4 is a diagram showing an example of noise measurement results in the inverter device of Fig. 2. Fig. 5 is a diagram explaining noise propagation paths in an inverter device using a conventional filter circuit. Fig. 6 is a circuit diagram showing a modified example of a filter circuit related to the embodiment. Fig. 7 is a circuit diagram showing another modified example of a filter circuit related to the embodiment.

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Fig. 1 shows a schematic configuration of an electric compressor 3 to which an inverter device 1 according to an embodiment of the present invention is applied. In Fig. 1, the electric compressor 3 is one of the devices provided in a vehicle air conditioning system mounted on a vehicle such as an automobile. The electric compressor 3 has a metal housing 31. The housing 31 includes a main housing 31A, an inverter housing 31B, and cover members 31C and 31D, which are integrally fastened together by bolts or the like (not shown).

[0011] The main housing 31A is cylindrical. The inverter housing 31B is cylindrical with a bottom, and its bottom wall is connected to one end (the left end in FIG. 1 ) of the main housing 31A. The other end (the right end in FIG. 1 ) of the main housing 31A is closed by a cover member 31C, and the open end of the inverter housing 31B is closed by a cover member 31D.

[0012] The main housing 31A accommodates a compression mechanism 32 that compresses a fluid (e.g., a refrigerant for a vehicle air conditioning system) and an electric motor 33 that drives the compression mechanism 32. An output shaft 33A of the electric motor 33 is connected to the compression mechanism 32. The main housing 31A also has a fluid intake port and a fluid discharge port (both not shown).

[0013] The inverter housing 31B accommodates the inverter device 1 according to this embodiment for driving the electric motor 33. The electric motor 33 and the inverter device 1 are connected by a power supply line (not shown) that passes through the bottom wall of the inverter housing 31B in an airtight and liquidtight state.

[0014] In the electric compressor 3 as described above, when the electric motor 33 is driven by the supply of electric power from the inverter device 1, the electric motor 33 drives the compression mechanism 32 via its output shaft 33A. Then, fluid drawn in from the suction port is compressed by the compression mechanism 32, and the compressed fluid is discharged from the discharge port.

[0015] FIG. 2 is a circuit diagram showing an example configuration of an inverter device 1 according to this embodiment. In FIG. 2, the inverter device 1 includes an inverter circuit 11 having multiple switching elements Q1 to Q6, a noise-reducing filter circuit 12 having a common-mode coil 12A, a Y capacitor 12B, and a resistor 12C, and a metal housing 13 that accommodates the inverter circuit 11 and the filter circuit 12. In this embodiment, the inverter housing 31B in the housing 31 of the electric compressor 3 serves as the housing 13 of the inverter device 1. The housing 13 (inverter housing 31B) is electrically connected to the metal body of the vehicle and serves as the reference ground. When expressed as an equivalent circuit, the housing 13 is earthed to a ground plane (ground surface) E via a contact resistance Rc. The potential of the housing 13 relative to the ground plane E is also referred to as the chassis ground.

[0016] The inverter circuit 11 is configured to supply power to an electric motor 33 driven by, for example, a three-phase AC power supply. The electric motor 33 has a U-phase coil 33U, a V-phase coil 33V, and a W-phase coil 33W, with the coils 33U to 33W being Y-connected. The inverter circuit 11 has U-phase switching elements Q1 and Q2 corresponding to the U-phase coil 33U, V-phase switching elements Q3 and Q4 corresponding to the V-phase coil 33V, and W-phase switching elements Q5 and Q6 corresponding to the W-phase coil 33W. Each of the switching elements Q1 to Q6 is a power switching element such as an insulated-gate bipolar transistor (IGBT). Freewheeling diodes D1 to D6 are connected to the switching elements Q1 to Q6, respectively.

[0017] The U-phase switching elements Q1, Q2 are connected in series to each other via a connecting wire, which is connected to the U-phase coil 33U. A series circuit formed by the U-phase switching elements Q1, Q2 is connected between a positive power supply line PL1 and a negative power supply line PL2. Each power supply line PL1, PL2 is electrically connected to a connector 14 provided on a housing 13, and DC power from a high-voltage battery 5 mounted on the vehicle is supplied to each power supply line PL1, PL2 via an HV harness 6 attached to the connector 14. In other words, DC power from the high-voltage battery 5 is input to the series circuit formed by the U-phase switching elements Q1, Q2.

[0018] The V-phase switching elements Q3, Q4 and the W-phase switching elements Q5, Q6 have the same circuit configuration as the U-phase switching elements Q1, Q2, except that they correspond to different coils of the electric motor 33. The switching operation of each of the switching elements Q1 to Q6 is controlled by a controller 11A.

[0019] The controller 11A controls the switching elements Q1 to Q6 by pulse width modulation (PWM) to periodically turn them on and off based on control signals from an air conditioning ECU (not shown) or the like mounted outside the inverter device 1. As a result, the inverter circuit 11 converts DC power from the high-voltage battery 5 into AC power and supplies it to the electric motor 33.

[0020] The filter circuit 12 is provided at the power input section of the inverter circuit 11, i.e., at a portion located between the inverter circuit 11 and the connector 14 on both the positive and negative power supply lines PL1, PL2. Specifically, the filter circuit 12 in this embodiment includes a common mode coil 12A inserted between the inverter circuit 11 and the connector 14 on both power supply lines PL1, PL2. The common mode coil 12A has a structure in which, for example, two conductors are wound in opposite directions around a single ferrite core. One conductor of the common mode coil 12A is inserted into the positive power supply line PL1, and both ends of the other conductor are inserted into the negative power supply line PL2.

[0021] One end of a Y capacitor 12B included in the filter circuit 12 is connected to a node n1 on the negative power supply line PL2 that connects between switching element Q2, one of the multiple switching elements Q1 to Q6 in the inverter circuit 11, and the other conductor of the common mode coil 12A. Furthermore, one end of a resistor 12C included in the filter circuit 12 is connected to the other end of the Y capacitor 12B. The other end of the resistor 12C is electrically connected to the housing 13 (inverter housing 31B) of the inverter device 1. In other words, the filter circuit 12 includes at least one pair of a Y capacitor 12B and a resistor 12C connected in series between the housing 13 and a node n1 located between the switching element Q2 and the common mode coil 12A on the negative power supply line PL2.

[0022] That is, the filter circuit 12 in this embodiment has a common mode coil 12A inserted on the positive power supply line PL1 and the negative power supply line PL2 at the power input section of the inverter circuit 11, and a Y capacitor 12B and a resistor 12C connected in series between the negative power supply line PL2 and the housing 13, thereby making it possible to reduce both AM band (0.5 to 1.8 MHz) and FM band (76 to 108 MHz) noise emitted from the inverter circuit 11. In this embodiment, the number of turns of each conductor of the common mode coil 12A and the like are optimized for the FM band.

[0023] The HV harness 6 attached to the connector 14 of the inverter device 1 has a positive conductor 61, a negative conductor 62, and a shielded wire 63. The positive conductor 61 electrically connects the positive electrode of the high-voltage battery 5 to a positive power supply line PL1 within the inverter device 1. The negative conductor 62 electrically connects the negative electrode of the high-voltage battery 5 to a negative power supply line PL2 within the inverter device 1. The shielded wire 63 is provided to cover the positive conductor 61 and the negative conductor 62 and is electrically connected to the housing 13 (inverter housing 31B) of the inverter device 1 via the connector 14. A floating capacitance Cs is generated between the negative conductor 62 and the shielded wire 63 within the HV harness 6. In addition, in Figure 2, the measuring device (LISN) 7 inserted between the negative terminal of the high-voltage battery 5 and the negative conductor 62 of the HV harness 6 is a well-known power line impedance stabilizing network for measuring noise propagating on the negative conductor 62.

[0024] Next, the effects of the inverter device 1 according to this embodiment will be described in detail with reference to Figures 3 to 5. Figure 3 shows noise propagation paths in the inverter device 1 of Figure 2. Figure 4 shows an example of noise measurement results in the inverter device 1 of Figure 2. Figure 5 shows noise propagation paths in an inverter device 100 using a conventional filter circuit.

[0025] First, a noise propagation path in an inverter device 100 using a conventional filter circuit will be described. As shown in Fig. 5, in the filter circuit 120 used in the conventional inverter device 100, a common-mode coil 120A is inserted on the positive power supply line PL1 and the negative power supply line PL2 at the power supply input section of an inverter circuit (INV) 110 similar to the inverter circuit 11 (Fig. 2) of the inverter device 1 according to this embodiment, and a Y capacitor 120B is connected between the negative power supply line PL2 and the housing 13. In other words, the conventional filter circuit 120 (Fig. 5) differs from this embodiment in that it does not have a configuration equivalent to the resistor 12C connected in series with the Y capacitor 12B in the filter circuit 12 (Figs. 2 and 3) of the inverter device 1 according to this embodiment.

[0026] 5, in the conventional filter circuit 120 as described above, the AM band noise Nam and the FM band noise Nfm that are generated in the inverter circuit 110 and propagate on the negative power supply line PL2 pass through the Y capacitor 120B and are transmitted to the housing 130 of the inverter device 100. The AM band noise Nam that has been transmitted to the housing 130 then passes through the contact resistance Rc between the housing 130 and the ground plane E and flows out to the ground plane E.

[0027] On the other hand, the FM band noise Nfm transmitted to the housing 130 is prevented from flowing out to the ground plane E due to the impedance of the contact resistance Rc, and propagates through the housing 130 to be transmitted to the shielded wire 63 of the HV harness 6 attached to the connector 140. The FM band noise Nfm transmitted to the shielded wire 63 is fed back to the negative conductor 62 via the stray capacitance Cs generated between the negative conductor 62 and the shielded wire 63 in the HV harness 6. The FM band noise Nfm propagating through such a feedback path does not pass through the common mode coil 120A and is therefore radiated to the outside of the inverter device 100 via the HV harness 6 without being reduced. In other words, in the inverter device 100 using the conventional filter circuit 120, the FM band noise Nfm that does not pass through the common mode coil 120A is radiated to the outside at a relatively high level, which can cause a deterioration in the noise level in on-board devices such as radio receivers.

[0028] In contrast to the conventional filter circuit 120 described above, the filter circuit 12 (FIGS. 2 and 3) of the inverter device 1 according to this embodiment has one end of a Y capacitor 12B connected to node n1 on the negative power supply line PL2, and the other end of the Y capacitor 12B is connected in series between the negative power supply line PL2 and the housing 13. In this manner, in the filter circuit 12 in which the Y capacitor 12B and the resistor 12C are connected in series between the negative power supply line PL2 and the housing 13, as shown by the thick arrow in FIG. 3, the AM band noise Nam generated in the inverter circuit (INV) 11 and propagating on the negative power supply line PL2 passes through the Y capacitor 12B and the resistor 12C to the housing 13, and further passes through the contact resistance Rc between the housing 13 and the ground plane E to flow out to the ground plane E.

[0029] On the other hand, FM band noise Nfm propagating on negative power supply line PL2 is not transmitted to housing 13 due to the impedance of resistor 12C connected in series to Y capacitor 12B, and propagates on negative power supply line PL2 toward common mode coil 12A. After reaching common mode coil 12A, the FM band noise Nfm is significantly reduced by passing through common mode coil 12A, and then propagates on negative conductor 62 of HV harness 6 connected to negative power supply line PL2 via connector 14.

[0030] The graph in Figure 4 shows the results of measuring the level of noise propagating on the negative conductor 62 of the HV harness 6 using a measuring device (LISN) 7 connected to the negative conductor 62 while changing the mounting conditions of the Y capacitor 12B and resistor 12C. The vertical axis represents the noise level (unit: dBμV), and the horizontal axis represents frequency (unit: MHz) on a logarithmic scale. The middle graph in Figure 4 is an enlarged view of the high-frequency band (40 to 100 MHz) including the FM band in the upper graph.

[0031] In the graph of Figure 4, curve M1 represents the noise measurement results when the Y capacitor 12B and resistor 12C are not installed. Curve M2 represents the noise measurement results when the Y capacitor 12B with a capacitance of 2.35 nF is installed and the resistor 12C is not installed. Curve M3 represents the noise measurement results when the Y capacitor 12B with a capacitance of 4.7 nF is installed and the resistor 12C is not installed. Curve M4 represents the noise measurement results when the Y capacitor 12B with a capacitance of 2.35 nF and the resistor 12C with an impedance of 18 Ω are installed. In other words, curve M2 or curve M3 represents an example of the noise reduction effect achieved by the conventional filter circuit 120 shown in Figure 5, and curve M4 represents an example of the noise reduction effect achieved by the filter circuit 12 of this embodiment shown in Figure 3.

[0032] Furthermore, the levels LIMam and LIMfm indicated by bold lines in the graph of Fig. 4 indicate the limit values ​​for the AM and FM bands in accordance with CISPR25 Ed4 Class 3, which specifies "Limit Values ​​and Measurement Methods of Interference Waves for the Protection of In-Vehicle Receivers." Furthermore, the table shown in the lower part of Fig. 4 shows the results of calculating the margin values ​​relative to the limit values ​​of CISPR25 Ed4 Class 3 for each AM and FM band for the noise measurement results indicated by each of the curves M1 to M4 in the graph of Fig. 4. Note that the larger the margin value relative to the limit value, the less noise there is (the better).

[0033] 4, it can be seen that under the condition (curve M1) where the Y capacitor 12B and resistor 12C of the filter circuit 12 are not implemented, the FM band noise Nfm is suppressed sufficiently below the limit value (LIMfm) by the common mode coil 12A, but the AM band noise Nam exceeds the limit value (LIMm). Also, under the condition (curve M2 or curve M3, corresponding to the conventional filter circuit 120) where the Y capacitor 12B of the filter circuit 12 is implemented but the resistor 12C is not implemented, the AM band noise Nam is suppressed below the limit value (LIMm), but due to the noise feedback to the negative electrode conductor 62 caused by the above-mentioned floating electrostatic capacitance Cs, the FM band noise Nfm approaches the limit value (LIMfm) (curve M3) or exceeds the limit value (LIMfm) (curve M2).

[0034] On the other hand, under the condition where both the Y capacitor 12B and the resistor 12C are implemented (curve M4, filter circuit 12 in this embodiment), it can be seen that the AM and FM band noises Nam and Nfm are kept sufficiently lower than the limit values ​​(LIMam, LIMfm) for each band due to the synergistic effect of the common mode coil 12A and the Y capacitor 12B with the resistor 12C connected in series. Note that the values ​​of the capacitance of the Y capacitor 12B and the impedance of the resistor 12C described above are merely examples and are not meant to be limiting.

[0035] That is, according to the filter circuit 12 of the present embodiment, of the noise emitted from the inverter circuit 11 and propagating on the negative power supply line PL2, FM band noise Nfm, which is a relatively high frequency band, passes through the first path P1 (indicated by the upper thick arrow and dashed arrow in FIG. 3 ) including the common mode coil 12A, thereby reducing the FM band noise Nfm radiated outside the inverter device 1 to a level sufficiently lower than the limit value (LIMfm). At the same time, AM band noise Nam, which is a relatively low frequency band, passes through the second path P2 (indicated by the lower thick arrow in FIG. 3 ) including the Y capacitor 12B and the resistor 12C and flows out to the ground plane E, thereby reducing the AM band noise Nam radiated outside the inverter device 1 to a level sufficiently lower than the limit value (LIMam).

[0036] In the filter circuit 12 configuration described above, the common mode coil 12A only needs to have the number of turns of each conductor optimized for the FM band, which is a relatively high frequency band, eliminating the need to provide multiple separate common mode coils for each frequency band. This allows for the inverter device 1 including the filter circuit 12 to be miniaturized and inexpensive. By supplying power output from the inverter device 1 according to this embodiment to the electric motor 33 that drives the electric compressor 3, it is possible to prevent the electric compressor 3 from becoming larger and more expensive due to measures to combat noise emitted from the inverter circuit 11, while also reducing the adverse effects of radiated noise on radio receivers and other devices installed in the vehicle.

[0037] Although the present invention has been described above as an embodiment, it is not limited to the above-described embodiment, and various modifications and variations are possible based on the technical concept of the present invention. For example, in the above-described embodiment, one end of Y capacitor 12B in filter circuit 12 is connected to node n1 on negative power supply line PL2, and one end of resistor 12C, the other end of which is connected to the other end of Y capacitor 12B, is connected to housing 13. However, for example, as shown in the modified example on the left side of Figure 6, it is also possible to reverse the connection order of Y capacitor 12B and resistor 12C, or to connect another capacitor 12D in series with Y capacitor 12B and resistor 12C, as shown in the modified example on the right side of Figure 6.

[0038] Specifically, in the modified example on the left side of Fig. 6, one end of resistor 12C is connected to node n1 on negative power supply line PL2, and one end of Y capacitor 12B, which has the other end connected to the other end of resistor 12C, is connected to housing 13 (reference ground). Also, in the modified example on the right side of Fig. 6, Y capacitor 12B and resistor 12C are connected in the same order as in the above-mentioned embodiment, and capacitor 12D, which is separate from Y capacitor 12B, is inserted between the other end of resistor 12C and housing 13. With this circuit configuration, it is possible to obtain the same effects as in the above-mentioned embodiment.

[0039] Furthermore, in the above-described embodiment, an example has been described in which the Y capacitor 12B and resistor 12C of the filter circuit 12 are connected in series between the negative power line PL2, of the positive and negative power lines PL1, PL2, and the housing 13. However, another modification, such as that shown in Fig. 7, is also possible. In the filter circuit 12' in the modification of Fig. 7, in addition to the Y capacitor 12B having one end connected to a node n1 located on the negative power line PL2 between the inverter circuit 11 and the common mode coil 12A, a Y capacitor 12B' having one end connected to a node n1' located on the positive power line PL1 between the inverter circuit 11 and the common mode coil 12A is provided. In this filter circuit 12', the other ends of the Y capacitors 12B and 12B' are connected to the housing 13 via a resistor 12C common to both.

[0040] 7 includes a common mode coil 12A inserted on both the positive and negative power supply lines PL1, PL2 at the power supply input section of the inverter circuit 11, a Y capacitor 12B and a resistor 12C connected in series between the negative power supply line PL2 and the housing 13, and a Y capacitor 12B' and a resistor 12C connected in series between the positive power supply line PL1 and the housing 13. The inverter device 1 including this filter circuit 12' can also achieve the same effects as those of the above-described embodiment. It is of course also possible to remove the Y capacitor 12B connected to node n1 on the negative power supply line PL2 from the filter circuit 12' and connect the Y capacitor 12B' and the resistor 12C in series only between the positive power supply line PL1 and the housing 13.

[0041] Furthermore, in the above-described embodiment, an example has been described in which AM band noise Nam and FM band noise Nfm are emitted from the inverter circuit 11, but the present invention is also effective in cases in which noise in a plurality of frequency bands other than the AM band or the FM band is emitted from the inverter circuit 11. Furthermore, in the above-described embodiment, an example has been described in which power output from the inverter device 1 is supplied to the electric motor 33 that drives the electric compressor 3, but in addition to this, the output power of the inverter device according to the present invention may also be supplied to, for example, a water heater provided in a vehicle air conditioning system.

[0042] 1, 1'... inverter device, 11... inverter circuit (INV), 11A... controller, 12, 12'... filter circuit, 12A... common mode coil, 12B, 12B'... Y capacitor, 12C... resistor, 13... housing, 14... connector, 3... electric compressor, 31... housing, 31B... inverter housing, 32... compression mechanism, 33... electric motor, 5... high voltage battery, 6... HV harness, 61... positive electrode side conductor, 62... negative electrode side conductor, 63... shielded wire, 7... measuring instrument (LISN), Cs... floating electrostatic capacitance, D1 to D6... freewheeling diodes, E... ground plane, Nam... AM band noise, Nfm... FM band noise, PL1... positive electrode side power supply line, PL2... negative electrode side power supply line, P1... first path, P2... second path, Q1 to Q6... switching elements, Rc... contact resistance

Claims

1. An inverter device for driving equipment provided in a vehicle air conditioning system, comprising: an inverter circuit having a plurality of switching elements; a filter circuit provided in a power input section of the inverter circuit; and a metal housing that houses at least the inverter circuit and the filter circuit, wherein the filter circuit includes: a common mode coil inserted in a power line passing through the power input section of the inverter circuit; and at least one set of Y capacitor and resistor connected in series between the power line connecting the switching elements and the common mode coil and the housing, wherein the inverter device is configured so that, of a plurality of noises of different frequency bands emitted from the inverter circuit, noise in a relatively high frequency band passes through a first path including the common mode coil, and noise in a relatively low frequency band passes through a second path including the Y capacitor and the resistor.

2. The inverter device according to claim 1, wherein the plurality of noises include AM band noise and FM band noise.

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