WO2023228642A1

WO2023228642A1 - Inverter device and electric compressor comprising same

Info

Publication number: WO2023228642A1
Application number: PCT/JP2023/015933
Authority: WO
Inventors: 康平 ▲高▼田; 浩吉田; 孝次小林
Original assignee: サンデン株式会社
Priority date: 2022-05-24
Filing date: 2023-04-21
Publication date: 2023-11-30
Also published as: JP2023172709A

Abstract

[Problem] To provide an inverter device that can effectively reduce noise by a common mode current while having a reduced size. [Solution] The inverter device comprises: an input side common mode coil 67 that is inserted into a single phase input unit of an inverter circuit 34; and an output side common mode coil 66 that is inserted into a three phase output unit of the inverter circuit 34. The input side common mode coil 67 and the output side common mode coil 66 are in an integral structure with a common core. Two wires on the positive side and the negative side of the input side common mode coil 67 are bifilar wound onto the core. Three wires of the UVW phases of the output side common mode coil 66 are trifilar wound onto the core.

Description

Inverter device and electric compressor equipped with it

The present invention relates to an inverter device that drives a motor, and an electric compressor equipped with the inverter device.

In a vehicle air conditioner for air conditioning the interior of an electric vehicle such as a hybrid vehicle or an electric vehicle, an electric compressor equipped with a motor is used instead of an engine-driven compressor. In that case, the vehicle is equipped with a high-voltage power source consisting of a high-voltage battery of about 300 VDC, for example, and a low-voltage power source consisting of a normal battery of about 12 VDC, and the inverter circuit of the inverter device converts the DC voltage of the high-voltage power source into alternating current. This voltage is supplied to the motor of the electric compressor.

On the other hand, a control circuit that controls an inverter circuit of an inverter device is supplied with power by converting, for example, a DC voltage from a low-voltage power supply into a predetermined voltage (for example, DC 15V, etc.) using a switching power supply device. Therefore, a switching power supply device is provided with a switching transformer made of an isolation transformer, and a low voltage circuit on the primary side of the switching transformer is insulated from a high voltage circuit on the secondary side. That is, an inverter device including a high voltage circuit supplied with power from a high voltage power supply and a low voltage circuit supplied with power from a low voltage power supply is housed in an inverter accommodating portion configured in the housing of the electric compressor. It was considered to be a form.

The electric circuit of the conventional electric compressor 100 will be explained using FIG. 12. In FIG. 12, 100 is a conventional electric compressor that constitutes a refrigerant circuit of a vehicle air conditioner mounted on an electric vehicle, and 2 indicates its housing. A compression mechanism (not shown) and a motor 8 for driving the compression mechanism are housed in the housing 2, and an inverter circuit 34 for driving the motor 8 and an inverter circuit 34 for controlling the inverter circuit 34 are housed in the inverter accommodating portion 6 of the housing 2. An inverter device 103 including a control circuit 36, a high voltage circuit filter (EMI filter) 37, a low voltage circuit filter (EMI filter) 38, a switching power supply device 39, and the like is housed.

The vehicle has a high voltage power source (HV power source) 41 consisting of, for example, a high voltage battery of about 300 V DC, for supplying power to the motor 8 of the electric compressor 100 and a driving motor (not shown), and a high voltage power source (HV power source) 41 of about 12 V DC. A low voltage power supply (LV power supply) 42 consisting of a battery is mounted. Furthermore, the housing 2 is electrically connected to the vehicle body (ground).

The inverter circuit 34 of the inverter device 103 is composed of six switching elements (not shown) including three-phase bridge-connected IGBTs, etc., and each switching element is driven by a gate drive signal generated by a gate driver included in the control circuit 36. controlled. Further, each switching element is arranged in a heat exchange relationship with the housing 2, and the heat generated by the switching element is released to the housing 2, so that the switching element is cooled. That is, the housing 2 serves as a heat sink for each switching element.

The control circuit 36 is composed of a microprocessor (CPU), and converts the DC voltage of the high voltage power supply 41 into an AC voltage of a predetermined frequency by switching each switching element of the inverter circuit 34 with a gate driver and performing PWM modulation. , is supplied to the motor 8.

The high voltage circuit filter 37 is connected between the high voltage power supply 41 and the inverter circuit 34 and is composed of a common mode coil 43,

Y capacitors

44 and 46, and a smoothing capacitor 47. This high voltage circuit filter 37 functions to reduce EMI noise generated by switching of the inverter circuit 34. The low voltage circuit filter 38 includes an X capacitor 48, a common mode coil 49,

Y capacitors

51 and 52, and a smoothing capacitor 53. The low voltage circuit filter 38 is connected between the low voltage power supply 42 and the switching power supply device 39, and functions to reduce EMI noise generated by switching in the switching power supply device 39.

The switching power supply device 39 is a DC-DC converter that switches the low voltage power supply 42 (DC 12V) to generate a predetermined DC voltage (HV15V, HV5V) and supplies power to the control circuit 36. Note that HV15V is a voltage supplied to a gate driver (which the control circuit 36 has) that generates a gate drive signal for the inverter circuit 34, and HV5V is a voltage that serves as a power source for the control circuit 36.

The switching power supply device 39 includes a switching transformer 60 including an isolation transformer (coupling transformer) including a primary winding 56 and a secondary winding 57 insulated from the primary winding 56; It has a switching element 58 connected to. Then, according to the turns ratio of the switching transformer 60, the switching element 58 is controlled to output DC15V (HV15V) and DC5V (HV5V).

The switching power supply device 39 switches the low voltage power supply 42 to supply power to the control circuit 36, and also connects the low voltage circuit 101 on the low voltage power supply 42 side, where the primary winding 56 is located, and the secondary winding by the switching transformer 60. The wire 57 is insulated from the high voltage circuit 102 on the high voltage power supply 41 side. The high voltage circuit 102 and low voltage circuit 101 of the inverter device 103 thus insulated are housed in the inverter accommodating portion 6 in close proximity to each other.

Japanese Patent Application Publication No. 2005-130575

Here, since the surge voltage (oscillating voltage) accompanying switching of the switching elements constituting the inverter circuit 34 is transmitted to the motor 8 side, the stray capacitance between the motor 8 and the housing 2 (indicated by 61 in FIG. 12) due to voltage fluctuations. Common mode current flows out through. Furthermore, there is also a common mode current flowing out through the stray capacitance (indicated by 62 in FIG. 12) between the inverter circuit 34 and the housing 2, which is a noise generation source (both indicated by arrows in FIG. 12).

In particular, in the electric compressor 100 as described above, noise (common mode noise) due to common mode current flowing out through the stray capacitance 61 between the motor 8 and the housing 2 and the stray capacitance 62 between the inverter circuit 34 and the housing 2 is generated. Become dominant.

On the other hand, in consumer equipment such as air conditioners and water heaters that use commercial AC as a power source, by inserting a common mode coil or ferrite core into the output section of the inverter circuit, the power source is Efforts were made to reduce noise by increasing the impedance of the outflow path.

However, in the inverter device 103 of the electric compressor 100 mounted on an electric vehicle as shown in FIG. In reality, it is difficult to take measures such as inserting a common mode coil into the output section or attaching a ferrite core.

Furthermore, even if the three-phase common mode coil 104 is inserted into the output part of the inverter circuit 34 in the high voltage circuit 102 (between the inverter circuit 34 and the motor 8) as shown in FIG. Since it is used as a heat sink for the switching element, noise caused by the common mode current flowing from the switching element of the inverter circuit 34, which is a noise generation source, to the housing 2 via the stray capacitance 62 cannot be suppressed.

On the other hand, in Patent Document 1, common mode coils are connected to the input/output section of the inverter circuit, and these are wound in parallel around the core. Applying this method to an electric compressor, for example, common mode coils are inserted into the input and output of the inverter circuit 34 shown in FIG. , if the UVW phase three-wire common mode coil (112U, 112V, 112W) on the three-phase output side is a common mode coil 114 wound in pentafilar around the core 113 in parallel as shown in FIG. It is expected that the common mode current (common mode noise) flowing out through the stray capacitance 61 between the motor 8 and the housing 2 and the stray capacitance 62 between the inverter circuit 34 and the housing 2 will be suppressed by magnetically coupling the output side with the motor 8. (The arrow in the figure indicates the direction of magnetic flux).

However, in the structure shown in Figure 14, unnecessary parasitic coupling (parasitic capacitance) occurs between the common mode coils on the input side and the output side, and due to the influence of this parasitic capacitance, the impedance in the high frequency band is higher than that of the three-phase output common mode coil alone. decreases, and the noise reduction effect in this band deteriorates. Further, since it is necessary to insulate all the

wires

111H, 111L, 112U, 112V, and 112W, the coil becomes large, which is not suitable for the electric compressor 100 as described above.

The present invention has been made to solve the conventional technical problems, and provides an inverter device that can effectively reduce noise caused by common mode current while also being miniaturized, and an electric compressor equipped with the inverter device. The purpose is to provide a machine.

The inverter device of the invention according to claim 1 is provided with a three-phase inverter circuit constituted by switching elements, and drives a motor by this inverter circuit, the input side being inserted into the single-phase input section of the inverter circuit. The common mode coil and the output common mode coil are inserted into the three-phase output section of the inverter circuit. The two wires on the positive and negative sides of the mode coil are bifilar wound around the core, and the three UVW phase wires of the output common mode coil are trifilar wound around the core.

The inverter device of the invention according to claim 2 is provided with a three-phase inverter circuit constituted by switching elements, and drives a motor by this inverter circuit, and an input side inserted into a single-phase input section of the inverter circuit. The common mode coil and the output common mode coil are inserted into the three-phase output section of the inverter circuit. The two wires on the positive and negative sides of the mode coil are divided and wound around the core, and the three wires on the UVW phase of the output common mode coil are trifilar-wound around the core.

The inverter device of the invention according to claim 3 is provided with a three-phase inverter circuit constituted by switching elements, and drives a motor by this inverter circuit, and the input side inserted into the single-phase input section of the inverter circuit. The common mode coil and the output common mode coil are inserted into the three-phase output section of the inverter circuit. The two wires on the positive and negative sides of the mode coil and the three wires on the UVW phase of the output common mode coil are each divided and wound around the core.

The inverter device of the invention according to claim 4 is characterized in that, in each of the above inventions, the inverter device includes a high voltage circuit including an inverter circuit to which power is supplied from the high voltage power supply, and a low voltage circuit to which power is supplied from the low voltage power supply. shall be.

The electric compressor of the invention according to claim 5 is characterized in that it includes a housing in which the motor is housed, and an inverter accommodating part configured in the housing, and the inverter device of the invention is housed in the inverter accommodating part. do.

The electric compressor of the invention according to claim 6 is characterized in that the housing in the above invention serves as a heat sink for the switching element.

The electric compressor of the invention of claim 7 is characterized in that it is mounted on a vehicle in the invention of claim 5.

According to the invention of claims 1 to 3, the input side common mode coil inserted in the single-phase input part of the inverter circuit and the output side common mode coil inserted in the three-phase output part of the inverter circuit are Since the core has an integral structure, the input side and the output side of the inverter circuit, which is the noise generation source, are magnetically coupled, and the impedance can be effectively increased before and after the noise source. This suppresses all common mode current flowing out through the stray capacitance between the motor and the housing that houses it, as well as the stray capacitance between the switching elements of the inverter circuit and the housing, significantly reducing common mode noise. You will be able to aim for

In addition, since the input side common mode coil and the output side common mode coil are magnetically coupled, it can be handled with only one core and the number of turns can be reduced. As a result, the inverter device including the high voltage circuit and the low voltage circuit as in the invention of claim 4 is accommodated in the housing, which is extremely advantageous for electric compressors as in claims 5 to 7 that require miniaturization. becomes. Furthermore, since this is a source measure that prevents noise from leaking into the housing, it is highly effective in suppressing high frequency noise.

In particular, compared to a structure in which two input wires and three output wires are wound in a pentafilar manner, it is possible to maintain magnetic coupling while suppressing unnecessary parasitic coupling between the windings, suppressing a drop in impedance in high frequency bands. As a result, the noise suppression effect is improved. Furthermore, since the insulation between the windings is simplified compared to pentafilar winding, further miniaturization can be achieved.

1 is a block diagram of an electric circuit of an electric compressor according to an embodiment of the present invention; FIG. 1 is a schematic cross-sectional view of an electric compressor according to an embodiment of the present invention. FIG. 2 is a diagram illustrating the structure of an example of a common mode coil inserted into an input part and an output part of an inverter circuit of the electric compressor shown in FIG. 1 (Example 1). 4 is a diagram illustrating inter-winding parasitic capacitance of the common mode coil having the structure shown in FIG. 3. FIG. FIG. 6 is a diagram illustrating impedance characteristics when the output side common mode coil of the inverter circuit is wound with a trifilar winding and when the input/output side common mode coil is wound with a pentafilar winding. FIG. 4 is a diagram illustrating impedance characteristics of a common mode coil having the structure shown in FIG. 3; 2 is a diagram illustrating noise in a high voltage circuit in the electric compressor of FIG. 1. FIG. 2 is a diagram illustrating noise in a low voltage circuit in the electric compressor of FIG. 1. FIG. FIG. 2 is a diagram illustrating the structure of another example of the common mode coil inserted into the input part and the output part of the inverter circuit of the electric compressor shown in FIG. 1 (Example 2). FIG. 3 is a diagram illustrating the structure of another example of the common mode coil inserted into the input part and the output part of the inverter circuit of the electric compressor shown in FIG. 1 (Example 3). 11 is a diagram illustrating impedance characteristics of common mode coils having the structures shown in FIGS. 3, 9, and 10. FIG. FIG. 2 is a block diagram of an electric circuit of a conventional electric compressor. 13 is a block diagram of an electric circuit when a common mode coil is inserted into the output section of the inverter circuit of the electric compressor shown in FIG. 12. FIG. FIG. 2 is a diagram illustrating a structure in which a common mode coil on the input/output side of an inverter circuit is wound with a pentafilar winding.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings. In each of the figures below, the parts indicated by the same reference numerals as those in FIGS. 6 and 7 have the same or similar functions.

First, an electric compressor (so-called inverter-integrated electric compressor) 1 according to an embodiment of the present invention will be described with reference to FIG. The electric compressor 1 of the embodiment constitutes a part of a refrigerant circuit of a vehicle air conditioner installed in an electric vehicle such as a hybrid vehicle or an electric vehicle.

(1) Structure of the electric compressor 1 In FIG. 2, the inside of the metallic cylindrical housing 2 of the electric compressor 1 is divided into a compression mechanism housing part 4 and an inverter housing part by a partition wall 3 that intersects in the axial direction of the housing 2. For example, a scroll-type compression mechanism 7 and a motor 8 for driving the compression mechanism 7 are housed in the compression mechanism accommodating portion 4.

In this case, the motor 8 of the embodiment is an IPMSM (Interior Permanent Magnet Synchronous Motor) consisting of a stator 9 fixed to the housing 2 and a rotor 11 rotating inside the stator 9.

A bearing part 12 is formed in the center of the partition wall 3 on the side of the compression mechanism housing part 4. One end of the drive shaft 13 of the rotor 11 is supported by this bearing part 12, and the other end of the drive shaft 13 is connected to the compression mechanism housing part 4. It is connected to 7. A suction port 14 is formed near the partition wall 3 at a position corresponding to the compression mechanism accommodating portion 4 of the housing 2, and when the rotor 11 (drive shaft 13) of the motor 8 rotates and the compression mechanism 7 is driven. A low-temperature refrigerant, which is a working fluid, flows into the compression mechanism accommodating portion 4 of the housing 2 through the suction port 14, and is sucked into the compression mechanism 7 and compressed.

The refrigerant compressed by the compression mechanism 7 to a high temperature and high pressure is discharged to the refrigerant circuit outside the housing 2 from a discharge port (not shown). Further, the low-temperature refrigerant flowing in from the suction port 14 passes near the partition wall 3, passes around the motor 8, and is sucked into the compression mechanism 7, so that the partition wall 3 is also cooled.

The inverter device 16 of the present invention that drives and controls the motor 8 is housed in the inverter housing section 6 that is separated from the compression mechanism housing section 4 by the partition wall 3 . In this case, the inverter device 16 is configured to supply power to the motor 8 via a sealed terminal or lead wire that penetrates the partition wall 3 .

(2) Structure of the inverter device 16 The inverter device 16 according to one embodiment of the present invention includes a substrate 17, six switching elements 18 wired on one side of the substrate 17, and wired on the other side of the substrate 17. The control circuit 36 includes a control circuit 36, an HV connector, an LV connector, etc. (not shown). In the embodiment, each switching element 18 is composed of an insulated gate bipolar transistor (IGBT) or the like in which a MOS structure is incorporated in the gate portion.

In this case, each switching element 18 constitutes a three-phase inverter circuit 34 to be described later, and the terminal portion 22 of each switching element 18 is connected to the substrate 17. The inverter device 16 assembled in this way is housed in the inverter accommodating portion 6 and attached to the partition wall 3 with one side on which each switching element 18 is located facing the partition wall 3, and is attached to the partition wall 3 with the cover 23. Blocked. In this case, the substrate 17 will be fixed to the partition wall 3 via the boss portion 24 that stands up from the partition wall 3.

With the inverter device 16 attached to the partition wall 3 in this manner, each switching element 18 is in close contact with the partition wall 3 either directly or via a predetermined insulating heat conductive material, and is in a heat exchange relationship with the partition wall 3 of the housing 2. becomes. As described above, since the partition wall 3 is cooled by the refrigerant sucked into the compression mechanism housing section 4, each switching element 18A is in a heat exchange relationship with the sucked refrigerant through the partition wall 3. The switching elements 18 are cooled by the refrigerant sucked into the compression mechanism accommodating portion 4 through the thickness, and each switching element 18 itself radiates heat to the refrigerant through the partition wall 3. That is, the housing 2 (partition wall 3) serves as a heat sink for each switching element 18.

(3) Circuit configuration of inverter device 16 Next, in FIG. 1, inverter device 16 of the present invention includes an inverter circuit 34 for driving motor 8, a control circuit 36 for controlling this inverter circuit 34, and a high voltage circuit. It is composed of a filter (EMI filter) 37, a low voltage circuit filter (EMI filter) 38, a switching power supply device 39, etc., and these are wired on the board 17 mentioned above and housed in the inverter accommodating part 6 as mentioned above. Ru.

The vehicle has a high voltage power source (HV power source) 41 consisting of, for example, a high voltage battery of approximately 300 V DC, for supplying power to the motor 8 of the electric compressor 1 and a driving motor (not shown), and a high voltage power source (HV power source) 41 of approximately 12 V DC. A low voltage power source (LV power source) 42 consisting of a battery is mounted, and the inverter device 16 is connected to the high voltage power source 41 through the aforementioned HV connector (not shown) and to the low voltage power source 42 through the LV connector. Furthermore, the housing 2 is electrically connected to the vehicle body (ground).

The inverter circuit 34 is composed of the aforementioned six switching elements 18 connected in a three-phase bridge, and each switching element 18 is controlled by a gate drive signal generated by a gate driver included in the control circuit 36. The control circuit 36 is composed of a microprocessor (CPU), and performs PWM modulation by switching each switching element 18 of the inverter circuit 34 with a gate driver, thereby converting the DC voltage of the high voltage power supply 41 into an AC voltage of a predetermined frequency. and supplies it to the motor 8.

Y capacitors

The switching power supply device 39 switches the low voltage power supply 42 to supply power to the control circuit 36, and also connects the low voltage circuit 63 on the low voltage power supply 42 side, where the primary winding 56 is located, and the secondary winding by the switching transformer 60. The wire 57 is insulated from the high voltage circuit 64 on the high voltage power supply 41 side. The inverter device 16 is configured such that the high voltage circuit 64 and the low voltage circuit 63 which are insulated as described above are placed close to each other on the substrate 17, and is housed in the inverter accommodating portion 6.

Here, as mentioned above, the surge voltage (oscillating voltage) accompanying the switching of the switching element 18 constituting the inverter circuit 34 is transmitted to the motor 8 side, so the surge voltage (oscillating voltage) accompanying the switching of the switching element 18 constituting the inverter circuit 34 is transmitted to the motor 8 side. Common mode current flows out. Furthermore, there is also a common mode current that flows out via the stray capacitance 62 between the inverter circuit 34 and the housing 2, which is a noise generation source (both are indicated by arrows in FIG. 1).

In particular, in the electric compressor 1 according to the embodiment, noise (common mode noise) is caused by a common mode current flowing out through the stray capacitance 61 between the motor 8 and the housing 2 and the stray capacitance 62 between the inverter circuit 34 and the housing 2. becomes dominant.

Therefore, in this embodiment, the input side common mode coil 67 is inserted into the single-phase input section of the inverter circuit 34 (the two wires between the smoothing capacitor 47 and the inverter circuit 34), and the input-side common mode coil 67 is inserted into the three-phase output section of the inverter circuit 34 (the inverter circuit 34). An output side common mode coil 66 is inserted into the three wires between the circuit 34 and the motor 8 (FIG. 1). In this case, as shown in FIG. 3, the input side common mode coil 67 and the output side common mode coil 66 are wound around one common core 68 to form a common mode coil 69 having an integral structure. Thereby, the input side common mode coil 67 and the output side common mode coil 66 are magnetically coupled (FIG. 1).

Furthermore, in the case of this embodiment, the input side common mode coil 67 has a positive electrode wire (winding: coil) 67H connected to the positive electrode side of the high voltage power supply 41 and a negative electrode wire connected to the negative electrode side, as shown in FIG. (Winding wire: coil) 67L, and these two

wires

67H and 67L on the positive electrode side and negative electrode side are bifilar-wound around the core 68, for example, in parallel. Further, as shown in FIG. 3, the output side common mode coil 66 includes a U phase line (winding: coil) 66U connected to the U phase of the output of the inverter circuit 34, and a V phase line (winding: coil) connected to the V phase. : Coil) 66V and W phase wire (winding: coil) 66W connected to W phase, these three

UVW phase wires

66U, 66V, 66W are trifilar wound around core 68 in parallel, for example. . Note that the arrows in FIG. 3 indicate the direction of magnetic flux.

In FIG. 4, L1 indicates the frequency characteristic of the inter-winding parasitic capacitance of the common mode coil 69 having the structure shown in FIG. It shows. As shown in FIG. 3, the input side common mode coil 67 is bifilar-wound, and the output side common-mode coil 66 is trifilar-wound, so that L100 in the case of FIG. 3 is different from L100 in the case of FIG. The parasitic capacitance between the input side common mode coil 67 and the output side common mode coil 66 is reduced (in the example, 20 pF is reduced to 10 pF).

Further, in the common mode coil 114 having the structure shown in FIG. 14, a resonance point is confirmed near the FM band. This is considered to be because unnecessary parasitic coupling (parasitic capacitance) occurred between the

lines

111H, 111L, 112U, 112V, and 112W on the input side and the output side, which caused the deterioration in the vicinity of 30 MHz to 50 MHz in the example. In addition, in the structure of FIG. 14, it is necessary to insulate all the

wires

111H, 111L, 112U, 112V, and 112W, which increases the size of the coil, but in the structure of FIG. Since there is no need to consider insulation between the output side common mode coil 66 and the output side common mode coil 66, miniaturization is possible, which is advantageous for the electric compressor 1.

5 shows the case where the common mode coil 104 is connected to the output side of the inverter circuit 34 as shown in FIG. 13, and each

wire

104U, 104V, 104W is wound in parallel around the core in a trifilar manner (L101), and the case shown in FIG. It shows the frequency characteristics of impedance in the case of the pentafilar-wound common mode coil 114 (L102).

Furthermore, FIG. 6 shows a case where the common mode coil 104 is connected as shown in FIG. 13, and each

wire

104U, 104V, 104W is wound in a trifilar around the core in parallel (L101), and when the input side is connected as in the example (FIG. 3). The frequency characteristics of the inverter in the case (L2) of the common mode coil 69 in which the common mode coil 67 is bifilar-wound and the output common mode coil 66 is trifilar-wound are shown.

In the pentafilar winding (L102) shown in FIG. 14, the parasitic capacitance between the windings is large, the occurrence of resonance is large in the high frequency band, and there is a point where the impedance is lower than that of L101 (see FIG. 5), but the structure of the embodiment shown in FIG. It can be seen that the common mode coil 69 can suppress the parasitic coupling between the windings, so it is possible to maintain the characteristic L101 of the trifilar-wound three-phase common mode coil 104 (Fig. 13) in the high band, as shown by L2 (Fig. 6).

(a) in FIG. 7 shows the noise measurement results of the high voltage circuit 64 in FIG. 1, where the horizontal axis is frequency and the vertical axis is noise. Further, L103 indicates the case of the above-mentioned FIG. 12, L104 indicates the common mode coil 114 in the case of the above-mentioned FIG. 14, and L3 indicates the case of the common mode coil 69 as in the embodiment of FIG. Further, (b) in FIG. 7 shows the improvement difference: L104-L3.

(a) in FIG. 8 shows the noise measurement results of the low voltage circuit 63 in FIG. 1, where the horizontal axis is frequency and the vertical axis is noise. Further, L105 indicates the case of the above-described FIG. 12, L106 indicates the common mode coil 114 in the case of the above-mentioned FIG. 14, and L4 indicates the case of the common mode coil 69 as in the embodiment of FIG. 3. Further, (b) in FIG. 8 shows the improvement difference: L106-L4.

In FIGS. 7(b) and 8(b), the larger the value is than 0, the more the noise is improved. As is clear from FIG. 7(b), in the case of the common mode coil 69 of the embodiment shown in FIG. The noise has been improved. Further, as is clear from FIG. 8(b), there is no adverse effect on the low voltage circuit 63. This is considered to be because unnecessary coupling is reduced by separating the input side common mode coil 67 and the output side common mode coil 66.

Next, FIG. 9 shows the structure of another embodiment of the common mode coil 69 in FIG. 1 (indicated by 69A). In this embodiment as well, as shown in FIG. 9, the input side common mode coil 67 and the output side common mode coil 66 are wound around a single common core 68 to form an integrated common mode coil 69A. Thereby, the input side common mode coil 67 and the output side common mode coil 66 are magnetically coupled.

However, in the case of this embodiment, the input side common mode coil 67 has a positive electrode wire (winding: coil) 67H connected to the positive electrode side of the high voltage power supply 41 and a negative electrode wire connected to the negative electrode side, as shown in FIG. (Winding wire: coil) Two wires of 67L are divided and wound around the core 68. Note that the output side common mode coil 66 has three

UVW phase wires

66U, 66V, and 66W wound around the core 68 in a trifilar manner, for example, in parallel, as in the case of FIG. Note that the arrows in FIG. 9 indicate the direction of magnetic flux. By dividing the positive electrode wire (winding: coil) 67H connected to the positive electrode side of the high voltage power supply 41 and the negative electrode wire (winding: coil) 67L connected to the negative electrode side as in this embodiment, The insulation structure becomes easy, and the common mode coil 69A can be downsized.

Further, FIG. 10 shows the structure of yet another embodiment of the common mode coil 69 in FIG. 1 (indicated by 69B). In this embodiment as well, as shown in FIG. 10, the input side common mode coil 67 and the output side common mode coil 66 are wound around one common core 68 to form an integrated common mode coil 69A. Thereby, the input side common mode coil 67 and the output side common mode coil 66 are magnetically coupled.

However, in the case of this embodiment, the input side common mode coil 67 has a positive electrode wire (winding: coil) 67H connected to the positive electrode side of the high voltage power supply 41 and a negative electrode wire connected to the negative electrode side, as shown in FIG. (Winding wire: coil) Two wires of 67L are divided and wound around the core 68. Further, the output side common mode coil 66 is also divided into three

UVW phase wires

66U, 66V, and 66W and wound around the core 68. Note that the arrows in FIG. 10 indicate the direction of magnetic flux.

FIG. 11 shows the frequency characteristics of the impedance of each common mode coil in the cases of FIG. 3 (Example 1), FIG. 9 (Example 2), FIG. 10 (Example 3), and FIG. In this figure, L5 indicates the common mode coil 69 in FIG. 3, L6 indicates the common mode coil 69A in FIG. 9, L7 indicates the common mode coil 69B in FIG. 10, and L107 indicates the common mode coil 114 in FIG. 14. .

It can be seen that both the common mode coil 69 (L5) in FIG. 3 and the common mode coil 69A (L6) in FIG. 9 have better impedance characteristics than the common mode coil 114 (L107) in FIG. 14. In the common mode coil 69 (L5: Example 1) in FIG. 3 and the common mode coil 69A (L6: Example 2) in FIG. It also has the effect of improving the impedance of. Moreover, it has the effect of being able to be made smaller compared to pentafilar winding (common mode coil 114: L107 in FIG. 14). Note that the common mode coil 69B (L7) in FIG. 10 has inferior characteristics to L107 (FIG. 14) from FIG. 11, but the common mode coil 69B (L7) in FIG. With respect to the trifilar winding of L6), the coupling coefficient of the three-phase output increases and the influence of mutual inductance increases, resulting in good impedance characteristics.

As described above, according to the present invention, the input side common mode coil 67 inserted into the single-phase input part of the inverter circuit 34 and the output side common mode coil 66 inserted into the three-phase output part of the inverter circuit 34, Since the common core 68 has an integral structure, the input side and the output side of the inverter circuit 34, which is a noise generation source, can be magnetically coupled and the impedance can be increased. This suppresses all common mode current flowing out through the stray capacitance 61 between the motor 8 and the housing 2 and the stray capacitance 62 between the switching element 18 of the inverter circuit 34 and the housing 2, and significantly reduces common mode noise. This makes it possible to achieve significant reductions.

Furthermore, since the input side common mode coil 67 and the output side common mode coil 66 are magnetically coupled, it can be handled with only one core 68, and the number of turns can also be reduced. As a result, the inverter device 16 including the high voltage circuit 64 and the low voltage circuit 63 is housed in the housing 2 as in the embodiment, which is extremely advantageous for the electric compressor 1 that needs to be downsized. Furthermore, since this is a source measure to prevent noise from leaking into the housing 2, the effect of suppressing high frequency noise is high.

In particular, compared to the structure shown in Figure 14 in which two input wires and three output wires are wound in a pentafilar style, it is possible to maintain magnetic coupling while suppressing unnecessary parasitic coupling between the windings, thereby suppressing a drop in impedance. As a result, the noise suppression effect is improved. Furthermore, since the insulation between the windings is simplified compared to the pentafilar winding (FIG. 14), further miniaturization can be achieved.

In the embodiment, a high voltage power source 41 consisting of a high voltage battery of approximately 300 VDC and a low voltage power source 42 consisting of a battery of approximately 12 VDC are provided. ), but the present invention is not limited to this, and the direct current voltage (HV15V, HV5V) on the high voltage circuit 64 side may be directly generated from the high voltage power supply 41.

Further, in the embodiments, the present invention has been described using an inverter device that drives the motor of an electric compressor, but the inventions of claims 1 to 4 are not limited thereto, and can be applied to various inverter devices that drive the motor. . Further, the specific configurations and numerical values shown in the examples are not limited to those, and can be variously changed without departing from the spirit of the present invention.

1 Electric compressor 2 Housing 3 Partition wall 6 Inverter housing 8 Motor 16 Inverter device 17 Board 18 Switching element 34 Inverter circuit 36 Control circuit 37 High voltage circuit filter 38 Low voltage circuit filter 39 Switching power supply device 41 High voltage power supply 42 Low voltage Power supply 63 Low voltage circuit 64 High voltage circuit 66 Output side common mode coil 66U U phase line 66V V phase line 66W W phase line 67 Input side common mode coil 67H Positive electrode line 67L Negative electrode line 68

Core

69, 69A, 69B Common mode coil

Claims

An inverter device comprising a three-phase inverter circuit configured with switching elements and driving a motor by the inverter circuit,
an input side common mode coil inserted into the single-phase input section of the inverter circuit;
comprising an output side common mode coil inserted in the three-phase output part of the inverter circuit,
The input side common mode coil and the output side common mode coil have an integral structure of a common core, and
The two wires on the positive and negative sides of the input common mode coil are bifilar wound around the core, and the three UVW phase wires of the output common mode coil are trifilar wound around the core. Features of the inverter device.
An inverter device comprising a three-phase inverter circuit configured with switching elements and driving a motor by the inverter circuit,
an input side common mode coil inserted into the single-phase input section of the inverter circuit;
comprising an output side common mode coil inserted in the three-phase output part of the inverter circuit,
The input side common mode coil and the output side common mode coil have an integral structure of a common core, and
The two wires on the positive and negative sides of the input common mode coil are divided and wound around the core, and the three UVW phase wires of the output common mode coil are trifilar-wound around the core. An inverter device featuring:
An inverter device comprising a three-phase inverter circuit configured with switching elements and driving a motor by the inverter circuit,
an input side common mode coil inserted into the single-phase input section of the inverter circuit;
comprising an output side common mode coil inserted in the three-phase output part of the inverter circuit,
The input side common mode coil and the output side common mode coil have an integral structure of a common core, and
An inverter device characterized in that two wires on the positive and negative sides of the input common mode coil and three wires on the UVW phase of the output common mode coil are each divided and wound around the core.
Any one of claims 1 to 3, comprising a high voltage circuit including the inverter circuit that is supplied with power from a high voltage power supply, and a low voltage circuit that is supplied with power from a low voltage power supply. The inverter device described in .
comprising a housing in which the motor is housed, and an inverter housing part configured in the housing,
The electric compressor equipped with an inverter device according to claim 4, wherein the inverter device is accommodated in the inverter accommodating portion.
The electric compressor according to claim 5, wherein the housing serves as a heat sink for the switching element.
The electric compressor according to claim 5, wherein the electric compressor is mounted on a vehicle.