Electric compressor
The electric compressor's noise reduction unit, featuring a common-mode choke coil and magnetic damping units, addresses the challenge of noise damping by increasing leakage inductance, thereby improving noise reduction performance.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TOYOTA INDUSTRIES CORP
- Filing Date
- 2024-12-06
- Publication Date
- 2026-06-18
AI Technical Summary
Existing electric compressors face challenges in achieving a better damping effect for reducing common-mode and normal-mode noise.
The electric compressor incorporates a noise reduction unit with a common-mode choke coil, a smoothing capacitor, a first damping unit made of a non-magnetic material, and a second damping unit made of a magnetic material, where the first damping unit surrounds the windings and the second damping unit is positioned to face the connection portions of the common-mode choke coil, increasing leakage inductance by reducing the distance between the connection portions and the damping unit.
This configuration enhances the damping effect by increasing leakage inductance, effectively reducing both common-mode and normal-mode noise.
Smart Images
Figure 2026099160000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an electric compressor.
Background Art
[0002] The electric compressor described in Patent Document 1 includes a compression unit that compresses a fluid, a motor that drives the compression unit, an inverter device that drives the motor, and a housing that houses the compression unit, the motor, and the inverter device. The inverter device has an inverter circuit section and a noise reduction section. The inverter circuit section converts DC power into AC power. The noise reduction section is provided on the input side of the inverter circuit section. The noise reduction section reduces common mode noise and normal mode noise.
[0003] The noise reduction section has a common mode choke coil, a smoothing capacitor, a first damping section, and a second damping section. The common mode choke coil reduces common mode noise. The common mode choke coil has a core made of a magnetic material, and a first winding and a second winding wound around the core. The smoothing capacitor constitutes a low-pass filter circuit together with the common mode choke coil. The first damping section is made of a non-magnetic material. The first damping section surrounds the first winding and the second winding. The second damping section is made of a magnetic material. The second damping section is disposed on the opposite side of the common mode choke coil with the first damping section interposed therebetween.
[0004] When normal-mode current flows through the first and second windings, magnetic flux leaks from the core. An induced current flows through the first damping section to generate a magnetic flux that resists the change in leakage flux leaking from the core. This induced current flowing through the first damping section is converted into thermal energy, thus providing a damping effect. Furthermore, when leakage flux leaking from the core flows through the second damping section, eddy currents are generated in the second damping section. These eddy currents generated in the second damping section are converted into thermal energy, also providing a damping effect. The first and second damping sections reduce normal-mode noise. [Prior art documents] [Patent Documents]
[0005] [Patent Document 1] Japanese Patent Publication No. 2024-132781 [Overview of the Initiative] [Problems that the invention aims to solve]
[0006] In such electric compressors, it is desirable to achieve a better damping effect. [Means for solving the problem]
[0007] An electric compressor that solves the above problems comprises a compression unit for compressing a fluid, a motor for driving the compression unit, an inverter device for driving the motor, and a housing for housing the compression unit, the motor, and the inverter device. The inverter device comprises an inverter circuit unit for converting DC power to AC power, and a noise reduction unit provided on the input side of the inverter circuit unit for reducing common-mode noise and normal-mode noise. The noise reduction unit comprises a common-mode choke coil for reducing common-mode noise, a smoothing capacitor that forms a low-pass filter circuit together with the common-mode choke coil, a first damping unit made of a non-magnetic material, and a second damping unit made of a magnetic material. The common-mode choke coil has a columnar first column, a columnar second column extending parallel to the first column, a columnar one-end connecting unit connecting one end of the first column and one end of the second column, and a columnar other-end connecting unit connecting the other end of the first column and the other end of the second column, and a core made of a magnetic material. The first damping section comprises a first winding wound around the first column and a second winding wound around the second column, and the first damping section surrounds the first and second windings, and reduces the normal mode noise by inducing a current to flow such that a magnetic flux is generated that resists the change in leakage magnetic flux leaking from the core, and the second damping section is arranged in a first direction, which is the direction in which the first and second column sections are aligned, sandwiching the common mode choke coil and the first damping section, and generating eddy currents due to the leakage magnetic flux An electric compressor that reduces normal mode noise by the means of, wherein the first column portion has a first inner surface facing the second column portion and a first outer surface which is the surface opposite to the first inner surface, and the second column portion has a second inner surface facing the first column portion and a second outer surface which is the surface opposite to the second inner surface, and the dimension in the first direction of at least one of the one-end connection portion and the other-end connection portion that faces the second damping portion is greater than the distance from the first outer surface to the second outer surface in the first direction.
[0008] With the above configuration, the distance from the core to the second damping section in the first direction becomes smaller compared to the case where the dimensions of each of the one-end and other-end connection sections in the first direction are less than or equal to the distance from the first outer surface to the second outer surface in the first direction. As a result, the leakage inductance due to leakage flux increases. Therefore, a better damping effect can be obtained.
[0009] In the above-described electric compressor, the one-end connection portion and the other-end connection portion face the second damping portion, and the dimensions of each of the one-end connection portion and the other-end connection portion in the first direction are preferably greater than the distance from the first outer surface to the second outer surface in the first direction.
[0010] According to the above configuration, both the distance from the one-end connection to the second damping section in the first direction and the distance from the other-end connection to the second damping section in the first direction can be reduced. Therefore, the leakage inductance is increased compared to the case where only one of the dimensions of the one-end connection in the first direction, or the dimensions of the other-end connection in the first direction, is greater than the distance from the first outer surface to the second outer surface in the first direction. Thus, an even better damping effect can be obtained.
[0011] The above-mentioned electric compressor may have a first projection that protrudes from the first outer surface toward the second damping portion and a second projection that protrudes from the second outer surface toward the second damping portion.
[0012] According to the above configuration, the distance from the one-end connection in the first direction to the second damping portion can be reduced at both ends of the one-end connection in the first direction. Similarly, the distance from the other-end connection in the first direction to the second damping portion can be reduced at both ends of the other-end connection in the first direction. As a result, the leakage inductance is increased compared to the case where the one-end connection and the other-end connection have only one of the first or second protrusions. Therefore, an even better damping effect can be obtained.
[0013] In the above-mentioned electric compressor, the second damping section is preferably arranged to surround the common mode choke coil and the first damping section. With the above configuration, an even better damping effect can be obtained compared to the case where the second damping section is positioned only between the common mode choke coil and the first damping section in the first direction.
[0014] The electric compressor described above may have the following: the second damping section may have two first portions that are positioned between the common mode choke coil and the first damping section in the first direction and extend in the second direction which is the direction in which the first column and the second column extend; two second portions that are positioned between the common mode choke coil and the first damping section in the second direction and extend in the first direction; and four third portions that are curved or straight and connect the first portions and the second portions.
[0015] According to the above configuration, since the second damping portion has a curved or straight third portion, the distance from the core to the second damping portion can be reduced at each corner of the second damping portion compared to the case where the second damping portion is, for example, a rectangular frame. As a result, the leakage inductance is increased. Therefore, an even better damping effect can be obtained. [Effects of the Invention]
[0016] According to the present invention, a superior damping effect can be obtained. [Brief explanation of the drawing]
[0017] [Figure 1] Figure 1 is a side cross-sectional view showing an electric compressor. [Figure 2] Figure 2 is a circuit diagram showing the electrical configuration of the electric compressor. [Figure 3] Figure 3 is a perspective view showing a portion of the holder and the second damping section. [Figure 4] FIG. 4 is a perspective view showing a common mode choke coil and a first damping portion. [Figure 5] FIG. 5 is a front view showing a holder, a common mode choke coil, a first damping portion, and a second damping portion. MODE FOR CARRYING OUT THE INVENTION
[0018] Hereinafter, an embodiment in which an electric compressor is embodied will be described with reference to FIGS. 1 to 5. The electric compressor of the present embodiment is mounted on a vehicle. The electric compressor of the present embodiment is used in a vehicle air conditioner.
[0019] As shown in FIG. 1, the vehicle air conditioner 100 includes an electric compressor 10 and an external refrigerant circuit 101. The external refrigerant circuit 101 supplies refrigerant as a fluid to the electric compressor 10. The external refrigerant circuit 101 has, for example, a heat exchanger and an expansion valve (not shown). In the vehicle air conditioner 100, the refrigerant is compressed by the electric compressor 10, and heat exchange and expansion of the refrigerant are performed by the external refrigerant circuit 101, thereby performing heating and cooling inside the vehicle.
[0020] The vehicle air conditioner 100 includes an air conditioning ECU 102. The air conditioning ECU 102 controls the entire vehicle air conditioner 100. The air conditioning ECU 102 is configured to be able to grasp the vehicle interior temperature, the set temperature of the car air conditioner, and the like. Then, the air conditioning ECU 102 transmits various commands such as ON / OFF commands to the electric compressor 10 based on parameters such as the vehicle interior temperature and the set temperature of the car air conditioner.
[0021] <Electric Compressor> The electric compressor 10 includes a housing 11, a rotating shaft 12, a compression portion 13 that compresses refrigerant, a motor 14 that drives the compression portion 13, and an inverter device 15 that drives the motor 14.
[0022] The housing 11 houses the rotating shaft 12, the compression unit 13, the motor 14, and the inverter device 15. The housing 11 is made of metal. In this embodiment, the housing 11 is made of aluminum. The housing 11 is grounded to the vehicle body. The housing 11 has an intake housing 21, a discharge housing 22, and an inverter housing 23.
[0023] The suction housing 21 has a plate-shaped end wall 21a and a circumferential wall 21b that extends cylindrically from the outer circumference of the end wall 21a. The discharge housing 22 is connected to the opening end of the suction housing 21. The discharge housing 22 closes the opening of the suction housing 21. The suction housing 21 and the discharge housing 22 partition the suction chamber S1. The rotating shaft 12, the compression unit 13, and the motor 14 are housed in the suction chamber S1. The motor 14 is positioned between the compression unit 13 and the end wall 21a of the suction housing 21 within the suction chamber S1.
[0024] The inverter housing 23 has a plate-shaped end wall 23a and a circumferential wall 23b that extends cylindrically from the outer circumference of the end wall 23a. The inverter housing 23 is connected to the end wall 21a of the intake housing 21 by bolts B. The end wall 21a of the intake housing 21 and the inverter housing 23 partition the inverter housing chamber S2. The inverter device 15 is housed in the inverter housing chamber S2.
[0025] A connector 16 is attached to the end wall 23a of the inverter housing 23. The connector 16 is electrically connected to a power storage device 103 mounted on the vehicle. The power storage device 103 is a power source that supplies power to equipment mounted on the vehicle. The power storage device 103 is a DC power source. The power storage device 103 is, for example, a secondary battery or a capacitor.
[0026] The housing 11 has an inlet 11a. The inlet 11a is formed in the peripheral wall 21b of the suction housing 21. The inlet 11a is formed in a part of the peripheral wall 21b of the suction housing 21 that is closer to the end wall 21a than the discharge housing 22. The housing 11 also has a discharge port 11b. The discharge port 11b is formed in the discharge housing 22. The inlet 11a is connected to one end of the external refrigerant circuit 101, and the discharge port 11b is connected to the other end of the external refrigerant circuit 101.
[0027] The rotating shaft 12 is supported in a rotatable manner relative to the housing 11. The axial direction of the rotating shaft 12 coincides with the axial direction of the peripheral wall 21b of the intake housing 21. The compression unit 13 is connected to the rotating shaft 12. The compression unit 13 compresses the refrigerant as the rotating shaft 12 rotates. The compression unit 13 is a scroll type, for example, consisting of a fixed scroll (not shown) fixed to the suction housing 21 and an orbiting scroll (not shown) positioned opposite the fixed scroll.
[0028] The motor 14 has a rotor 31 and a stator 32. The rotor 31 has a cylindrical rotor core 33 and permanent magnets (not shown) provided on the rotor core 33. The rotating shaft 12 is inserted through the rotor core 33. The rotating shaft 12 is fixed to the rotor core 33. The rotating shaft 12 can rotate integrally with the rotor 31.
[0029] The stator 32 is radially opposite the rotor 31 and the rotation axis 12. The stator 32 has a cylindrical stator core 34 and a u-phase coil 35u, a v-phase coil 35v, and a w-phase coil 35w. The stator core 34 is fixed to the inner circumferential surface of the peripheral wall 21b of the intake housing 21. The u-phase coil 35u, v-phase coil 35v, and w-phase coil 35w are each wound around the stator core 34. The u-phase coil 35u, v-phase coil 35v, and w-phase coil 35w are, for example, Y-connected. The connection configuration of the u-phase coil 35u, v-phase coil 35v, and w-phase coil 35w is not limited to a Y-connection and is arbitrary. The connection configuration of the u-phase coil 35u, v-phase coil 35v, and w-phase coil 35w may be, for example, a delta connection.
[0030] The rotor 31 rotates when the u-phase coil 35u, v-phase coil 35v, and w-phase coil 35w are energized in a predetermined pattern. When the rotor 31 rotates, the rotating shaft 12 rotates. This drives the compression unit 13. Therefore, the motor 14 drives the compression unit 13. The compression unit 13 compresses the refrigerant drawn into the intake chamber S1 from the external refrigerant circuit 101 through the intake port 11a. The refrigerant compressed by the compression unit 13 is discharged to the external refrigerant circuit 101 through the discharge port 11b.
[0031] As shown in Figures 1 and 2, the inverter device 15 includes a circuit board 41, a holder 42, an inverter circuit section 43, a control section 44, and a noise reduction section 50. The circuit board 41 is positioned between the end wall 21a of the intake housing 21 and the end wall 23a of the inverter housing 23 in the axial direction of the rotation axis 12. The thickness direction of the circuit board 41 coincides with the axial direction of the rotation axis 12.
[0032] The holder 42 is made of resin. The holder 42 is positioned between the circuit board 41 and the end wall 21a of the suction housing 21. The holder 42 has a plate-shaped main body portion 45 and a cylindrical portion 46. The thickness direction of the main body portion 45 coincides with the axial direction of the rotation axis 12. The cylindrical portion 46 is erected from the main body portion 45 toward the end wall 21a of the suction housing 21.
[0033] As shown in Figure 3, the cylindrical portion 46 of this embodiment has two first wall portions 46a, two second wall portions 46b, and four third wall portions 46c. The two first wall portions 46a are opposite each other. The two second wall portions 46b are opposite each other in directions perpendicular to the direction in which the two first wall portions 46a are opposite each other. The third wall portions 46c connect the first wall portions 46a and the second wall portions 46b. The four third wall portions 46c are located at the four corners of the cylindrical portion 46. The third wall portions 46c of this embodiment are curved.
[0034] The inverter circuit 43 converts DC power to AC power. As shown in Figure 1, in this embodiment, the inverter circuit 43 is positioned between the main body 45 of the holder 42 and the end wall 21a of the suction housing 21 in the axial direction of the rotating shaft 12. The inverter circuit 43 is mounted on a circuit board 41.
[0035] As shown in Figure 2, the inverter circuit 43 has two connection lines EL1 and EL2. The inverter circuit 43 is equipped with u-phase switching elements Qu1 and Qu2 corresponding to the u-phase coil 35u. The inverter circuit 43 is equipped with v-phase switching elements Qv1 and Qv2 corresponding to the v-phase coil 35v. The inverter circuit 43 is equipped with w-phase switching elements Qw1 and Qw2 corresponding to the w-phase coil 35w. Each switching element Qu1 to Qw2 is a power switching element such as an IGBT. Each switching element Qu1, Qu2, Qv1, Qv2, Qw1, and Qw2 is connected to a freewheeling diode Du1, Du2, Dv1, Dv2, Dw1, and Dw2, respectively.
[0036] Each u-phase switching element Qu1 and Qu2 are connected in series. The connection between each u-phase switching element Qu1 and Qu2 is made to the u-phase coil 35u. The series connection of each u-phase switching element Qu1 and Qu2 is electrically connected to both connection lines EL1 and EL2.
[0037] Each v-phase switching element Qv1 and Qv2 is connected in series. The connection between each v-phase switching element Qv1 and Qv2 is made to a v-phase coil of 35V. The series connection of each v-phase switching element Qv1 and Qv2 is electrically connected to both connection lines EL1 and EL2.
[0038] Each w-phase switching element Qw1 and Qw2 is connected in series. The connection between each w-phase switching element Qw1 and Qw2 is made to a w-phase coil 35w. The series connection of each w-phase switching element Qw1 and Qw2 is electrically connected to both connection lines EL1 and EL2.
[0039] The control unit 44 controls the inverter circuit unit 43. The control unit 44 controls the switching operation of each switching element Qu1 to Qw2. The control unit 44 can be implemented, for example, by one or more dedicated hardware circuits and / or one or more processors (control circuits) that operate according to a computer program (software). The processor includes a CPU and memory such as RAM and ROM, and the memory stores, for example, program code or instructions configured to cause the processor to execute various processes. Memory, or computer-readable media, includes any available media that can be accessed by a general-purpose or dedicated computer.
[0040] The control unit 44 is electrically connected to the air conditioning ECU 102 via the connector 16. Based on commands from the air conditioning ECU 102, the control unit 44 periodically turns each switching element Qu1 to Qw2 ON / OFF. More specifically, based on commands from the air conditioning ECU 102, the control unit 44 performs pulse width modulation (PWM) control on each switching element Qu1 to Qw2. More specifically, the control unit 44 generates a control signal using a carrier signal and a command voltage value signal (comparison signal). Then, the control unit 44 converts DC power to AC power by performing ON / OFF control of each switching element Qu1 to Qw2 using the generated control signal.
[0041] <Noise Reduction Section> The noise reduction unit 50 is provided on the input side of the inverter circuit unit 43. The noise reduction unit 50 reduces common-mode noise and normal-mode noise. In this embodiment, the noise reduction unit 50 is positioned between the main body 45 of the holder 42 and the end wall 21a of the suction housing 21 in the axial direction of the rotating shaft 12. The noise reduction unit 50 is mounted on the circuit board 41.
[0042] The noise reduction unit 50 includes a common-mode choke coil 51 and a smoothing capacitor 52. The smoothing capacitor 52, together with the common-mode choke coil 51, constitutes a low-pass filter circuit 56. The low-pass filter circuit 56 is provided on connection lines EL1 and EL2. Circuit-wise, the low-pass filter circuit 56 is provided between the connector 16 and the inverter circuit 43. The common-mode choke coil 51 is provided on both connection lines EL1 and EL2.
[0043] The smoothing capacitor 52 is located on the inverter circuit section 43 side relative to the common mode choke coil 51. The smoothing capacitor 52 is an X capacitor connected in parallel to the inverter circuit section 43. The smoothing capacitor 52 is electrically connected to both connection lines EL1 and EL2. The common mode choke coil 51 and the smoothing capacitor 52 constitute an LC resonant circuit. Therefore, the low-pass filter circuit 56 in this embodiment is an LC resonant circuit including the common mode choke coil 51.
[0044] The noise reduction unit 50 has two Y capacitors 53. The two Y capacitors 53 are connected in series. The space between the two Y capacitors 53 is grounded to the vehicle body via the housing 11. The two Y capacitors 53 are located on the inverter circuit unit 43 side relative to the common mode choke coil 51. The two Y capacitors 53 are connected in parallel with the common mode choke coil 51. The two Y capacitors 53 are connected in parallel with the smoothing capacitor 52. The two Y capacitors 53 are located between the common mode choke coil 51 and the smoothing capacitor 52.
[0045] <Common mode choke coil> The common-mode choke coil 51 suppresses the transmission of high-frequency noise generated on the vehicle side to the inverter circuit section 43 of the electric compressor 10. The common-mode choke coil 51 reduces common-mode noise. Furthermore, the common-mode choke coil 51 utilizes its leakage inductance as normal inductance. As a result, the common-mode choke coil 51 is used as the L component in the low-pass filter circuit (LC filter) 56 for removing normal-mode noise (differential-mode noise). In other words, the common-mode choke coil 51 can handle both common-mode noise and normal-mode noise (differential-mode noise). Therefore, in the electric compressor 10 of this embodiment, instead of using separate choke coils for common-mode and normal-mode (differential-mode) noise, the common-mode choke coil 51 handles both modes of noise.
[0046] As shown in Figure 4, the common mode choke coil 51 has a core 60, a first winding 71, and a second winding 72. The core 60 is made of a ferromagnetic material. For example, the core 60 is a ferrite core.
[0047] As shown in Figure 5, the core 60 has a columnar first column portion 61, a columnar second column portion 62, a columnar one-end connecting portion 63, and a columnar other-end connecting portion 64. The second column portion 62 extends parallel to the first column portion 61. In the following description, the direction in which the first column portion 61 and the second column portion 62 are aligned is referred to as the first direction X. The direction in which the first column portion 61 and the second column portion 62 extend is referred to as the second direction Y. The direction perpendicular to the first direction X and the second direction Y is referred to as the third direction Z. The first column portion 61 has a first inner surface 61a facing the second column portion 62, and a first outer surface 61b which is the surface opposite to the first inner surface 61a. The second column portion 62 has a second inner surface 62a facing the first column portion 61, and a second outer surface 62b which is the surface opposite to the second inner surface 62a.
[0048] The one-end connection portion 63 connects one end of the first column portion 61 to one end of the second column portion 62 in the first direction X, and the other-end connection portion 64 connects the other end of the first column portion 61 to the other end of the second column portion 62 in the first direction X. The dimension X1 of the one-end connection portion 63 in the first direction X is greater than the distance X2 from the first outer surface 61b of the first column portion 61 to the second outer surface 62b of the second column portion 62 in the first direction X. The dimension X1 of the other-end connection portion 64 in the first direction X is greater than the distance X2 from the first outer surface 61b to the second outer surface 62b in the first direction X.
[0049] As shown in Figures 4 and 5, the first winding 71 is wound around the first column portion 61 of the core 60. The second winding 72 is wound around the second column portion 62 of the core 60. The first winding 71 and the second winding 72 are not wound around the one-end connection portion 63 and the other-end connection portion 64 of the core 60. Both ends of the first winding 71 are drawn out from the core 60 as first lead portions 71a. Both ends of the second winding 72 are drawn out from the core 60 as second lead portions 72a.
[0050] <First Dumping Section> The noise reduction unit 50 has a first damping unit 54 that reduces normal mode noise. In Figure 4, the first damping unit 54 is shown by a dashed line. The first damping unit 54 is made of a conductive nonmagnetic material. For example, the first damping unit 54 is made of copper or aluminum.
[0051] The first damping portion 54 is annular. The first damping portion 54 surrounds a portion of the common mode choke coil 51. The first damping portion 54 surrounds a portion of the first column portion 61 and a portion of the second column portion 62 of the core 60, a portion of the first winding 71, and a portion of the second winding 72. The first damping portion 54 has two first plate portions 54a located on both sides of the common mode choke coil 51 in the third direction Z, and two second plate portions 54b located on both sides of the common mode choke coil 51 in the first direction X. A through hole 54h is provided in one of the two first plate portions 54a.
[0052] Although not shown in the diagram, the first damping section 54 is composed of two parts: a first member that constitutes one first plate section 54a and two second plate sections 54b, and a second member that constitutes the other first plate section 54a.
[0053] The one-end connection portion 63 and the other-end connection portion 64 of the core 60 are located outside the first damping portion 54. The one-end connection portion 63 and the other-end connection portion 64 are positioned with the first damping portion 54 in between in the second direction Y. In this embodiment, the dimension X1 of the one-end connection portion 63 in the first direction X and the dimension X1 of the other-end connection portion 64 in the first direction X are each smaller than the dimension X3 of the first damping portion 54 in the first direction X. The dimension X1 of the one-end connection portion 63 in the first direction X may be greater than or equal to the dimension X3 of the first damping portion 54 in the first direction X. The dimension X1 of the other-end connection portion 64 in the first direction X may be greater than or equal to the dimension X3 of the first damping portion 54 in the first direction X.
[0054] The common mode choke coil 51 and the first damping portion 54 are housed in a housing space 47 partitioned by the main body portion 45 and the inner circumferential surface of the cylindrical portion 46 of the holder 42. The axial direction of the cylindrical portion 46 is parallel to the third direction Z. Of the two first plate portions 54a, the one without the through hole 54h is located between the common mode choke coil 51 and the main body portion 45 of the holder 42. Each first lead portion 71a and each second lead portion 72a are electrically connected to the circuit board 41 by passing through the main body portion 45. Of the two first plate portions 54a, the one with the through hole 54h is located between the common mode choke coil 51 and the end wall 21a of the suction housing 21. A thermal grease (not shown) is provided between the common mode choke coil 51 and the first damping portion 54 and the end wall 21a of the suction housing 21. The second plate portion 54b is located between the common mode choke coil 51 and the first wall portion 46a of the cylindrical portion 46 of the holder 42.
[0055] <Second Dumping Section> As shown in Figures 3 and 5, the noise reduction unit 50 has a second damping unit 55 that reduces normal mode noise. The second damping unit 55 is made of a conductive magnetic material. The second damping unit 55 is made of, for example, iron or electrical steel. The second damping unit 55 is plate-shaped. The thickness of the second damping unit 55 in this embodiment is several hundred μm. However, the thickness of the second damping unit 55 is exaggerated in the drawings.
[0056] The second damping portion 55 in this embodiment is cylindrical. The second damping portion 55 is provided on the outer surface of the cylindrical portion 46. The second damping portion 55 is provided on the outer circumferential surface of the cylindrical portion 46, for example, by insert molding. The second damping portion 55 has two first portions 55a, two second portions 55b, and four third portions 55c. The two first portions 55a are provided on the outer surfaces of the two first wall portions 46a. The two second portions 55b are provided on the outer surfaces of the two second wall portions 46b. The four third portions 55c are provided on the outer surfaces of the four third wall portions 46c. The third portions 55c in this embodiment are curved.
[0057] As described above, the common mode choke coil 51 and the first damping section 54 are arranged inside the cylindrical section 46. Therefore, the second damping section 55 is arranged to surround the common mode choke coil 51 and the first damping section 54.
[0058] The two first sections 55a are positioned in the first direction X with the common mode choke coil 51 and the first damping section 54 in between. Therefore, the second damping section 55 is positioned in the first direction X with the common mode choke coil 51 and the first damping section 54 in between. Each first section 55a extends in the second direction Y. The two second sections 55b are positioned in the second direction Y with the common mode choke coil 51 and the second damping section 55 in between. Each second section 55b extends in the first direction X. The four third sections 55c connect the first sections 55a and the second sections 55b. The four third sections 55c are located at the four corners of the second damping section 55.
[0059] In this embodiment, the one-end connecting portion 63 and the other-end connecting portion 64 each face the second damping portion 55 in the first direction X via the cylindrical portion 46 of the holder 42. In this embodiment, the one-end connecting portion 63 and the other-end connecting portion 64 each have a first projection 65 that protrudes toward the second damping portion 55 from the first outer surface 61b of the first column portion 61, and a second projection 66 that protrudes toward the second damping portion 55 from the second outer surface 62b of the second column portion 62.
[0060] In this embodiment, the distance from each connection part 63, 64 to the first part 55a in the first direction X is approximately the same as the distance from each connection part 63, 64 to the second part 55b in the second direction Y. The distance from each connection part 63, 64 to the first part 55a in the first direction X may be greater than or less than the distance from each connection part 63, 64 to the second part 55b in the second direction Y.
[0061] In this embodiment, the distance from each connection point 63, 64 to the third part 55c in the first direction X decreases as you move from the first part 55a towards the second part 55b. The distance from each connection point 63, 64 to the third part 55c in the second direction Y decreases as you move from the second part 55b towards the first part 55a.
[0062] [Operation of this embodiment] The operation of this embodiment will now be explained. The noise reduction unit 50 has a common mode choke coil 51 that reduces common mode noise. The common mode choke coil 51 has a core 60 made of a magnetic material, a first winding 71, and a second winding 72. The core 60 has a columnar first column portion 61, a columnar second column portion 62, a columnar one-end connecting portion 63, and a columnar other-end connecting portion 64. The first winding 71 is wound around the first column portion 61. The second column portion 62 extends parallel to the first column portion 61. The second winding 72 is wound around the second column portion 62. The one-end connecting portion 63 connects one end of the first column portion 61 to one end of the second column portion 62. The other-end connecting portion 64 connects the other end of the first column portion 61 to the other end of the second column portion 62.
[0063] The noise reduction unit 50 includes a first damping unit 54 made of a non-magnetic material and a second damping unit 55 made of a magnetic material. The first damping unit 54 surrounds the first winding 71 and the second winding 72. The second damping unit 55 is positioned in the first direction X with the common mode choke coil 51 and the first damping unit 54 sandwiched between them.
[0064] When normal-mode current (differential-mode current) flows through the first winding 71 and the second winding 72, magnetic flux leaks from the core 60. The leakage flux leaking from the core 60 links with the first damping section 54. As a result, an induced current flows in the circumferential direction of the first damping section 54 in order to generate a magnetic flux that resists the change in leakage flux. The induced current flowing through the first damping section 54 is converted into thermal energy. This provides a damping effect. Also, as shown by the dashed line in Figure 5, when leakage flux flows through the second damping section 55, eddy currents are generated in the second damping section 55. The eddy currents generated in the second damping section 55 are converted into thermal energy. This also provides a damping effect.
[0065] In this embodiment, the one-end connection portion 63 of the core 60 faces the second damping portion 55. The dimension X1 of the one-end connection portion 63 in the first direction X is greater than the distance X2 from the first outer surface 61b of the first column portion 61 to the second outer surface 62b of the second column portion 62 in the first direction X. As a result, the distance from the one-end connection portion 63 to the second damping portion 55 in the first direction X is smaller compared to the case where the dimension X1 of the one-end connection portion 63 in the first direction X is less than or equal to the distance X2 from the first outer surface 61b to the second outer surface 62b in the first direction X. In other words, the air gap in the magnetic path from the one-end connection portion 63 to the second damping portion 55 is reduced.
[0066] The other end connection portion 64 of the core 60 faces the second damping portion 55. The dimension X1 of the other end connection portion 64 in the first direction X is greater than the distance X2 from the first outer surface 61b to the second outer surface 62b in the first direction X. As a result, the distance from the other end connection portion 64 to the second damping portion 55 in the first direction X is smaller compared to the case where the dimension X1 of the other end connection portion 64 in the first direction X is less than or equal to the distance X2 from the first outer surface 61b to the second outer surface 62b in the first direction X. In other words, the air gap in the magnetic path from the other end connection portion 64 to the second damping portion 55 is reduced.
[0067] Therefore, the leakage inductance due to leakage flux increases. Consequently, a better damping effect can be obtained. [Effects of this embodiment] The effects of this embodiment will now be explained.
[0068] (1) The dimension X1 of the one-end connecting portion 63 facing the second damping portion 55 in the first direction X is greater than the distance X2 from the first outer surface 61b to the second outer surface 62b in the first direction X. With this configuration, the distance from the one-end connecting portion 63 to the second damping portion 55 in the first direction X is smaller compared to the case where the dimension X1 of the one-end connecting portion 63 in the first direction X is less than or equal to the distance X2 from the first outer surface 61b to the second outer surface 62b in the first direction X. Similarly, the dimension X1 of the other-end connecting portion 64 facing the second damping portion 55 in the first direction X is greater than the distance X2 from the first outer surface 61b to the second outer surface 62b in the first direction X. With this configuration, the distance from the other end connection portion 64 to the second damping portion 55 in the first direction X becomes smaller compared to the case where the dimension X1 of the other end connection portion 64 in the first direction X is less than or equal to the distance X2 from the first outer surface 61b to the second outer surface 62b in the first direction X. As a result, the leakage inductance due to leakage flux increases. Therefore, a better damping effect can be obtained.
[0069] (2) The one-end connection portion 63 and the other-end connection portion 64 face the second damping portion 55. The dimension X1 of each of the one-end connection portion 63 and the other-end connection portion 64 in the first direction X is greater than the distance X2 from the first outer surface 61b to the second outer surface 62b in the first direction X.
[0070] This configuration allows for a reduction in both the distance from the one-end connection portion 63 to the second damping portion 55 in the first direction X, and the distance from the other-end connection portion 64 to the second damping portion 55 in the first direction X. As a result, the leakage inductance increases compared to the case where only one of the dimensions X1 of the one-end connection portion 63 and the dimension X1 of the other-end connection portion 64 in the first direction X is greater than the distance X2 from the first outer surface 61b to the second outer surface 62b in the first direction X. Therefore, an even better damping effect can be obtained.
[0071] (3) The one-end connecting portion 63 and the other-end connecting portion 64 each have a first projection 65 that protrudes from the first outer surface 61b toward the second damping portion 55 and a second projection 66 that protrudes from the second outer surface 62b toward the second damping portion 55.
[0072] With this configuration, the distance from the one-end connection portion 63 to the second damping portion 55 in the first direction X can be reduced at both ends of the one-end connection portion 63 in the first direction X. Similarly, the distance from the other-end connection portion 64 to the second damping portion 55 in the first direction X can be reduced at both ends of the other-end connection portion 64 in the first direction X. As a result, the leakage inductance is increased compared to the case where the one-end connection portion 63 and the other-end connection portion 64 have only one of the first protrusion 65 and the second protrusion 66. Therefore, an even better damping effect can be obtained.
[0073] (4) The second damping section 55 is arranged to surround the common mode choke coil 51 and the first damping section 54. With this configuration, an even better damping effect can be obtained compared to the case where the second damping section 55 is positioned only between the common mode choke coil 51 and the first damping section 54 in the first direction X.
[0074] (5) The second damping section 55 has two first sections 55a, two second sections 55b, and four third sections 55c. The two first sections 55a are positioned in the first direction X with the common mode choke coil 51 and the first damping section 54 in between. The first sections 55a extend in the second direction Y. The two second sections 55b are positioned in the second direction Y with the common mode choke coil 51 and the first damping section 54 in between. The second sections 55b extend in the first direction X. The third sections 55c connect the first sections 55a and the second sections 55b. The third sections 55c are curved.
[0075] With this configuration, since the second damping portion 55 has a curved third portion 55c, the distance from the core 60 to the second damping portion 55 can be reduced at each corner of the second damping portion 55 compared to the case where the second damping portion 55 is, for example, rectangular. As a result, the leakage inductance is increased. Therefore, an even better damping effect can be obtained.
[0076] (6) The first winding 71 and the second winding 72 are not wound around the one-end connection 63 and the other-end connection 64. This increases the leakage inductance compared to the case where a portion of the first winding 71 and the second winding 72 are wound around the one-end connection 63 and the other-end connection 64. Therefore, an even better damping effect can be obtained.
[0077] (7) The noise reduction unit 50 of this embodiment has a first damping unit 54 surrounding the first winding 71 and the second winding 72. The first damping unit 54 is located between the first winding 71 or the second winding 72 and the second damping unit 55 in the first direction X. Therefore, compared to the case in which the noise reduction unit 50 does not have the first damping unit 54, it is difficult to reduce the distance between the core 60 and the second damping unit 55 in the first direction X.
[0078] In this embodiment, the dimension X1 in the first direction X of the one-end connection portion 63 and the other-end connection portion 64 of the core 60, which are the parts around which the first winding 71 and the second winding 72 are not wound, is made larger than the distance X2 from the first outer surface 61b to the second outer surface 62b in the first direction X. As a result, even if the noise reduction portion 50 has a first damping portion 54, the distance between the core 60 and the second damping portion 55 in the first direction X can be reduced.
[0079] (8) A heat dissipation grease (not shown) is provided between the common mode choke coil 51 and the first damping section 54 and the end wall 21a of the suction housing 21. The heat from the common mode choke coil 51 and the first damping section 54 is dissipated to the suction housing 21 via the heat dissipation grease.
[0080] As described above, in this embodiment, the dimension X1 of the one-end connection portion 63 and the other-end connection portion 64 in the first direction X is greater than the distance X2 from the first outer surface 61b to the second outer surface 62b in the first direction X. Therefore, compared to the case where the dimension X1 of the one-end connection portion 63 and the other-end connection portion 64 in the first direction X is less than or equal to the distance X2 from the first outer surface 61b to the second outer surface 62b in the first direction X, the heat dissipation surface of the core 60 is increased. Thus, the heat dissipation performance of the core 60 can be improved.
[0081] [Example of changes] The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.
[0082] ○ When both the one-end connection portion 63 and the other-end connection portion 64 face the second damping portion 55, either the dimension X1 of the one-end connection portion 63 in the first direction X, or the dimension X1 of the other-end connection portion 64 in the first direction X, may be greater than the distance X2 from the first outer surface 61b to the second outer surface 62b in the first direction X.
[0083] Depending on the shape of the second damping portion 55, one of the one-end connecting portion 63 and the other-end connecting portion 64 may face the second damping portion 55, while the other does not necessarily face the second damping portion 55. In this case, the dimension X1 in the first direction X of the one of the one-end connecting portion 63 and the other-end connecting portion 64 that faces the second damping portion 55 is greater than the distance X2 from the first outer surface 61b to the second outer surface 62b in the first direction X.
[0084] In other words, the dimension X1 in the first direction X of at least one of the one-end connecting portion 63 and the other-end connecting portion 64 that faces the second damping portion 55 should be greater than the distance X2 from the first outer surface 61b of the first column portion 61 to the second outer surface 62b of the second column portion 62 in the first direction X.
[0085] ○ When the dimension X1 of the one-end connecting portion 63 facing the second damping portion 55 in the first direction X is greater than the distance X2 from the first outer surface 61b to the second outer surface 62b in the first direction X, the one-end connecting portion 63 may have only one of the first protrusion 65 and the second protrusion 66.
[0086] When the dimension X1 of the other end connecting portion 64 facing the second damping portion 55 in the first direction X is greater than the distance X2 from the first outer surface 61b to the second outer surface 62b in the first direction X, the other end connecting portion 64 may have only one of the first protrusion 65 and the second protrusion 66.
[0087] In Figure 4, the one-end connecting portion 63 and the other-end connecting portion 64 protrude from the first column portion 61 and the second column portion 62 in the first direction X as well as the third direction Z, but they do not necessarily have to protrude in the third direction Z.
[0088] ○ If the second damping section 55 is positioned between the common mode choke coil 51 and the first damping section 54 in the first direction X, the shape of the second damping section 55 may be changed as appropriate.
[0089] The third portion 55c of the second damping portion 55 may extend in a straight line. That is, the second damping portion 55 may be octagonal in shape. Even in this case, the same effects as those of the above embodiment (4) and (5) can be obtained.
[0090] The second damping portion 55 may be in the shape of a rectangular frame. In other words, the second damping portion 55 does not have to have a third portion 55c. The second damping section 55 does not have to be arranged to surround the common mode choke coil 51 and the first damping section 54. For example, the second damping section 55 may be provided only on the outer surfaces of the two first wall sections 46a of the cylindrical section 46.
[0091] ○ The method for providing the second damping portion 55 to the cylindrical portion 46 of the holder 42 is not limited to insert molding. For example, the second damping portion 55 may be attached to the cylindrical portion 46 by adhesive.
[0092] ○ The shape of the cylindrical portion 46 of the holder 42 may be appropriately changed according to the shape of the second damping portion 55. ○ The compression section 13 is not limited to a scroll type; for example, it may be a piston type, a vane type, or the like.
[0093] ○ The electric compressor 10 may be installed in a fuel cell vehicle. In this case, the compression unit 13 compresses air, which is supplied as a fluid to the fuel cell. [Note] The technical concepts that can be understood from the above embodiments and modified examples are described below.
[0094] <Note 1> The device comprises a compression unit for compressing a fluid, a motor for driving the compression unit, an inverter device for driving the motor, and a housing for housing the compression unit, the motor, and the inverter device. The inverter device includes an inverter circuit unit for converting DC power to AC power, and a noise reduction unit provided on the input side of the inverter circuit unit for reducing common-mode noise and normal-mode noise. The noise reduction unit includes a common-mode choke coil for reducing common-mode noise, a smoothing capacitor that, together with the common-mode choke coil, constitutes a low-pass filter circuit, a first damping unit made of a non-magnetic material, and a second damping unit made of a magnetic material. The common-mode choke coil has a columnar first column, a columnar second column extending parallel to the first column, a columnar one-end connecting portion connecting one end of the first column and one end of the second column, and a columnar other-end connecting portion connecting the other end of the first column and the other end of the second column, and also has a core made of a magnetic material and is wound around the first column. The first damping section has a first winding and a second winding wound around the second column, and the first damping section surrounds the first winding and the second winding, and reduces the normal mode noise by inducing a current to flow such that a magnetic flux is generated that resists the change in leakage magnetic flux leaking from the core, and the second damping section is arranged with the common mode choke coil and the first damping section sandwiched between them in a first direction which is the direction in which the first column and the second column are aligned, and reduces the normal mode noise by generating eddy currents due to the leakage magnetic flux An electric compressor for reducing normal mode noise, wherein the first column portion has a first inner surface facing the second column portion and a first outer surface which is the surface opposite to the first inner surface, and the second column portion has a second inner surface facing the first column portion and a second outer surface which is the surface opposite to the second inner surface, and the dimension in the first direction of at least one of the one-end connection portion and the other-end connection portion facing the second damping portion is greater than the distance from the first outer surface to the second outer surface in the first direction.
[0095] <Note 2> The electric compressor as described in Appendix 1, wherein the one-end connection portion and the other-end connection portion face the second damping portion, and the dimensions of each of the one-end connection portion and the other-end connection portion in the first direction are greater than the distance from the first outer surface to the second outer surface in the first direction.
[0096] <Note 3> The electric compressor according to Appendix 2, wherein the one-end connecting portion and the other-end connecting portion each have a first protrusion projecting from the first outer surface toward the second damping portion and a second protrusion projecting from the second outer surface toward the second damping portion.
[0097] <Note 4> The electric compressor described in any one of the appendices 1 to 3, wherein the second damping section is arranged to surround the common mode choke coil and the first damping section.
[0098] <Note 5> The electric compressor according to Appendix 4, wherein the second damping portion has two first portions that are positioned between the common mode choke coil and the first damping portion in the first direction and extend in the second direction which is the direction in which the first column portion and the second column portion extend, two second portions that are positioned between the common mode choke coil and the first damping portion in the second direction and extend in the first direction, and four curved or straight third portions that connect the first portions and the second portions. [Explanation of symbols]
[0099] 10...Electric compressor, 11...Housing, 13...Compression section, 14...Motor, 15...Inverter device, 43...Inverter circuit section, 50...Noise reduction section, 51...Common mode choke coil, 52...Smoothing capacitor, 54...First damping section, 55...Second damping section, 55a...First part, 55b...Second part, 55c...Third part, 56...Low-pass filter circuit, 60...Core, 61...First column section, 61a...First inner surface, 61b...First outer surface, 62...Second column section, 62a...Second inner surface, 62b...Second outer surface, 63...One end connection section, 64...Other end connection section, 65...First protrusion, 66...Second protrusion, 71...First winding, 72...Second winding, X...First direction, Y...Second direction.
Claims
1. It comprises a compression unit for compressing a fluid, a motor for driving the compression unit, an inverter device for driving the motor, and a housing for housing the compression unit, the motor, and the inverter device. The inverter device comprises an inverter circuit section that converts DC power to AC power, and a noise reduction section provided on the input side of the inverter circuit section that reduces common-mode noise and normal-mode noise. The noise reduction unit comprises a common-mode choke coil for reducing common-mode noise, a smoothing capacitor that, together with the common-mode choke coil, constitutes a low-pass filter circuit, a first damping unit made of a non-magnetic material, and a second damping unit made of a magnetic material. The common mode choke coil is, The core, made of a magnetic material, has a columnar first column, a columnar second column extending parallel to the first column, a columnar one-end connecting portion connecting one end of the first column and one end of the second column, and a columnar other-end connecting portion connecting the other end of the first column and the other end of the second column. The first winding wound around the first column, The second winding wound around the second column, It has, The first damping section surrounds the first winding and the second winding, and reduces the normal mode noise by allowing an induced current to flow so as to generate a magnetic flux that resists the change in leakage magnetic flux leaking from the core. The second damping section is arranged between the common mode choke coil and the first damping section in a first direction in which the first column section and the second column section are aligned, and reduces the normal mode noise by generating eddy currents due to the leakage magnetic flux, The first column portion has a first inner surface facing the second column portion and a first outer surface which is the surface opposite to the first inner surface. The second column portion has a second inner surface facing the first column portion and a second outer surface that is the surface opposite to the second inner surface. An electric compressor in which the dimension in the first direction of at least one of the one-end connection portion and the other-end connection portion that faces the second damping portion is greater than the distance from the first outer surface to the second outer surface in the first direction.
2. The one-end connection portion and the other-end connection portion face the second damping portion, The electric compressor according to claim 1, wherein the dimensions of each of the one-end connection portion and the other-end connection portion in the first direction are greater than the distance from the first outer surface to the second outer surface in the first direction.
3. The electric compressor according to claim 2, wherein the one-end connecting portion and the other-end connecting portion each have a first projection that protrudes from the first outer surface toward the second damping portion and a second projection that protrudes from the second outer surface toward the second damping portion.
4. The electric compressor according to claim 1, wherein the second damping section is arranged to surround the common mode choke coil and the first damping section.
5. The second damping section is, Two first portions are positioned in the first direction with the common mode choke coil and the first damping portion sandwiched between them, and extending in a second direction which is the direction in which the first column portion and the second column portion extend, Two second portions are positioned in the second direction, sandwiching the common mode choke coil and the first damping portion between them, and extending in the first direction, Four curved or straight third parts connecting the first part and the second part, An electric compressor according to claim 4, having the following features.