Electric compressor

Abstract

The present application provides an electric compressor. A damping portion has a flat plate-shaped damping bent portion bent from a damping side portion and thermally coupled to a heat radiation surface. Thus, heat generated by the damping portion is transmitted from the damping bent portion to the heat radiation surface of the inverter housing in addition to the damping side portion.

Description

Technical Field

[0001] This disclosure relates to electric compressors. Background Technology

[0002] An electric compressor includes a housing, a compressor section, an electric motor, and a converter unit. Fluid is drawn into the housing. The compressor section compresses the fluid. The electric motor includes the compressor section. The converter unit drives the electric motor. The converter unit includes a converter circuit. The converter circuit converts direct current (DC) power into alternating current (AC) power. The converter unit includes a noise reduction section. The noise reduction section is located on the input side of the converter circuit. The noise reduction section includes a common-mode choke and a smoothing capacitor. The smoothing capacitor and the common-mode choke together form a low-pass filter circuit. Furthermore, the noise reduction section reduces the common-mode noise and constant-mode noise contained in the DC power input to the converter circuit. Additionally, the converter unit includes a converter housing. The converter housing is thermally coupled to the housing. The converter housing houses the converter circuit and the noise reduction section.

[0003] The common-mode choke has a ring-shaped core, a first winding, and a second winding. The first winding is wound around the core. The second winding is wound around the core and faces the first winding. Additionally, the converter device described, for example, in International Publication No. 2017 / 170819, also includes a damping section. The damping section forms a magnetic circuit for the leakage flux generated from the common-mode choke to increase the leakage inductance of the common-mode choke. The damping section is made of a strongly magnetic metal. The damping section has a damping side portion. The damping side portion covers at least a portion of the side surface of the common-mode choke. The top end of the damping side portion is thermally coupled to the heat dissipation surface of the converter housing or casing.

[0004] Eddy currents are generated within the damping section by the leakage flux generated from the common-mode choke. These eddy currents are thermally converted by the damping section. Thus, the damping section functions as an impedance relative to the leakage flux, thereby producing a damping effect. As a result, resonance peaks generated by the low-pass filter circuit can be suppressed. The heat generated by the damping section is transferred from the damping side to the heat dissipation surface. Therefore, the heat generated by the damping section is dissipated by the heat dissipation surface.

[0005] In such a damping section, there is a desire to improve the heat dissipation performance of the damping section. Summary of the Invention

[0006] According to one aspect of this disclosure, an electric compressor is provided, comprising: a housing that draws in fluid; a compression section configured to compress the fluid; an electric motor configured to drive the compression section; and a converter device configured to drive the electric motor, the converter device comprising: a converter circuit configured to convert direct current (DC) power into alternating current (AC) power; a noise reduction section disposed on the input side of the converter circuit and configured to reduce common-mode noise and constant-mode noise contained in the DC power before it is input to the converter circuit; and a converter housing thermally coupled to the housing and housing the converter circuit and the noise reduction section, the noise reduction... The component includes: a common-mode choke; and a smoothing capacitor, the smoothing capacitor and the common-mode choke together forming a low-pass filter circuit. The common-mode choke has: a ring-shaped core; a first winding wound around the core; and a second winding wound around the core and facing the first winding. The damping portion forms a magnetic circuit for the leakage flux generated from the common-mode choke to increase the leakage inductance of the common-mode choke. The damping portion is made of a strongly magnetic metal body. The damping portion has a damping side portion covering at least a portion of the side surface of the common-mode choke. The damping side portion is thermally coupled to the heat dissipation surface of the converter housing or the casing. The damping portion has a flat plate-shaped damping bend portion that bends from the damping side portion and is thermally coupled to the heat dissipation surface. Attached Figure Description

[0007] Figure 1 This is a side sectional view showing the electric compressor in the embodiment.

[0008] Figure 2 This is a circuit diagram showing the electrical configuration of an electric compressor.

[0009] Figure 3 It is an exploded perspective view schematically showing the structure of the noise reduction section and its surroundings.

[0010] Figure 4 This is a top view of the common-mode choke.

[0011] Figure 5 This is a schematic top view showing a portion of the noise reduction section and the converter housing.

[0012] Figure 6 This is an unfolded diagram showing the damping section.

[0013] Figure 7 This is a graph showing the frequency characteristics of a low-pass filter circuit relative to constant-mode noise.

[0014] Figure 8This is a top view schematically showing a noise reduction section and a portion of the converter housing in other embodiments. Detailed Implementation

[0015] The following is based on Figures 1-7 An electric compressor according to one embodiment will be described. The electric compressor of this embodiment is used, for example, in a vehicle air conditioning system.

[0016] <Vehicle air conditioning unit 10>

[0017] like Figure 1 As shown, the vehicle air conditioning unit 10 includes an electric compressor 11 and an external refrigerant circuit 12. The external refrigerant circuit 12 supplies refrigerant as a fluid to the electric compressor 11. The external refrigerant circuit 12 includes, for example, a heat exchanger and an expansion valve. The vehicle air conditioning unit 10 cools or heats the vehicle interior by compressing the refrigerant with the electric compressor 11 and by the external refrigerant circuit 12 performing heat exchange and expansion of the refrigerant.

[0018] The vehicle air conditioning system 10 includes an air conditioning ECU 13. The air conditioning ECU 13 controls the entire vehicle air conditioning system 10. The air conditioning ECU 13 is configured to monitor the interior temperature and the set temperature of the vehicle air conditioning system. Furthermore, based on parameters such as the interior temperature and the set temperature of the vehicle air conditioning system, the air conditioning ECU 13 sends various commands such as ON (on) / OFF (off) commands to the electric compressor 11.

[0019] <Basic Components of Electric Compressor 11>

[0020] The electric compressor 11 includes a housing 14. The housing 14 is formed of a metal material with good thermal conductivity, such as aluminum. The housing 14 is grounded in the vehicle body.

[0021] The housing 14 has an intake housing 15 and an exhaust housing 16. The intake housing 15 and the exhaust housing 16 are assembled together. The intake housing 15 has a plate-shaped end wall 15a and a cylindrical peripheral wall 15b. The peripheral wall 15b extends cylindrically from the outer periphery of the end wall 15a. The exhaust housing 16 is assembled to the intake housing 15 while blocking the opening of the intake housing 15. Thus, an internal space is formed within the housing 14.

[0022] The housing 14 has a suction port 14a. Refrigerant is drawn in from the external refrigerant circuit 12 through the suction port 14a. Therefore, refrigerant is drawn into the housing 14. The suction port 14a is formed in the peripheral wall 15b of the suction housing 15. Specifically, the suction port 14a is formed in the peripheral wall 15b of the suction housing 15 at a location closer to the end wall 15a than the discharge housing 16. The housing 14 has a discharge port 14b. The discharge port 14b discharges refrigerant to the external refrigerant circuit 12. The discharge port 14b is formed in the discharge housing 16.

[0023] The electric compressor 11 includes a rotating shaft 17, a compression unit 18, and an electric motor 19. The rotating shaft 17, the compression unit 18, and the electric motor 19 are housed within a housing 14. The rotating shaft 17 is supported in a rotatable manner relative to the housing 14. The rotating shaft 17 is arranged within the housing 14 with its axial direction aligned with the axial direction of the peripheral wall 15b.

[0024] The compression unit 18 is housed within the suction housing 15. The compression unit 18 is, for example, a scroll member consisting of a fixed scroll member (not shown) fixed within the suction housing 15 and a rotating scroll member (not shown) arranged opposite to the fixed scroll member. The compression unit 18 is positioned within the suction housing 15 closer to the discharge port 14b than the suction port 14a. The compression unit 18 is connected to a rotating shaft 17. The compression unit 18 is driven by the rotation of the rotating shaft 17 to compress the refrigerant.

[0025] An electric motor 19 is housed within a suction housing 15. The electric motor 19 is positioned between a compression section 18 and an end wall 15a within the suction housing 15. The electric motor 19 has a rotor 20 and a stator 21. The stator 21 has a cylindrical stator core 22, a u-phase coil 23u, a v-phase coil 23v, and a w-phase coil 23w.

[0026] The u-phase coil 23u, v-phase coil 23v, and w-phase coil 23w are wound on the stator core 22. The u-phase coil 23u, v-phase coil 23v, and w-phase coil 23w are, for example, Y-connected. However, the connection method of the u-phase coil 23u, v-phase coil 23v, and w-phase coil 23w is not limited to Y-connection and is arbitrary. For example, the u-phase coil 23u, v-phase coil 23v, and w-phase coil 23w can also be delta-connected.

[0027] The rotor 20 is cylindrical. The rotor 20 is fixed to the rotating shaft 17. Thus, the rotating shaft 17 is configured to rotate integrally with the rotor 20. The stator 21 is fixed to the peripheral wall 15b of the suction housing 15. The rotor 20 and the stator 21 are radially opposite each other on the rotating shaft 17.

[0028] The rotor 20 rotates by energizing the u-phase coil 23u, v-phase coil 23v, and w-phase coil 23w in a predetermined pattern. As the rotor 20 rotates, the rotating shaft 17 rotates, thereby driving the compression unit 18. Therefore, the electric motor 19 drives the compression unit 18. Furthermore, refrigerant flowing in the external refrigerant circuit 12 is drawn into the housing 14 through the suction port 14a. The compression unit 18 compresses the refrigerant drawn into the housing 14. The compressed refrigerant is discharged from the discharge port 14b into the external refrigerant circuit 12.

[0029] The electric compressor 11 includes a converter device 30. The converter device 30 drives an electric motor 19. The converter device 30 includes a converter housing 31. The converter housing 31 is formed, for example, of a metal material such as aluminum.

[0030] The converter housing 31 has a base member 32 and a cover member 33. The base member 32 is plate-shaped. The base member 32 contacts the outer surface of the end wall 15a of the intake housing 15 through a heat-dissipating grease (not shown). Therefore, the converter housing 31 is thermally coupled to the housing 14. The cover member 33 has a plate-shaped end wall 33a and a cylindrical peripheral wall 33b. The cover member 33 is assembled to the base member 32 with the open end of the peripheral wall 33b mating with the base member 32. The base member 32 and the cover member 33 form a converter receiving chamber S1. Therefore, the converter housing 31 has a converter receiving chamber S1. The base member 32 and the cover member 33 are fixed to the intake housing 15 by bolts B1. Thus, the converter device 30 is mounted on the housing 14.

[0031] The electric compressor 11 includes a connector 27. The connector 27 is electrically connected to an energy storage device 28 mounted on the vehicle. The connector 27 is disposed on the converter housing 31. The connector 27 protrudes from the end wall 33a of the cover member 33. The energy storage device 28 is a power source that supplies electricity to machinery (equipment) mounted on the vehicle. The energy storage device 28 is a DC power source. The energy storage device 28 may be, for example, a secondary battery or a capacitor.

[0032] The converter device 30 has a circuit board 34. The circuit board 34 is housed in the converter housing chamber S1. The circuit board 34 is arranged opposite to the end wall 15a at a predetermined interval in the axial direction of the rotation axis 17. The circuit board 34 is housed in the converter housing chamber S1 with the thickness direction of the circuit board 34 aligned with the axial direction of the rotation axis 17.

[0033] The converter device 30 includes a converter circuit 35 and a noise reduction unit 36. The converter circuit 35 converts direct current (DC) power into alternating current (AC) power. The noise reduction unit 36 ​​is provided on the input side of the converter circuit 35. The noise reduction unit 36 ​​reduces the common-mode noise and constant-mode noise contained in the DC power input to the converter circuit 35. The converter circuit 35 and the noise reduction unit 36 ​​are mounted on a circuit board 34. Therefore, the converter housing 31 houses the converter circuit 35 and the noise reduction unit 36.

[0034] <Converter Circuit 35>

[0035] like Figure 2As shown, the converter circuit 35 has two connection lines EL1 and EL2. The converter circuit 35 has u-phase switching elements Qu1 and Qu2 corresponding to the u-phase coil 23u. The converter circuit 35 has v-phase switching elements Qv1 and Qv2 corresponding to the v-phase coil 23v. The converter circuit 35 has w-phase switching elements Qw1 and Qw2 corresponding to the w-phase coil 23w. Each switching element Qu1 to Qw2 is, for example, a power switching element such as an IGBT. Furthermore, each switching element Qu1, Qu2, Qv1, Qv2, Qw1, and Qw2 has a return-current diode (body diode) Du1, Du2, Dv1, Dv2, Dw1, and Dw2.

[0036] Each u-phase switching element Qu1 and Qu2 is connected in series. Each u-phase switching element Qu1 and Qu2 is connected to the u-phase coil 23u. Furthermore, the series connection of each u-phase switching element Qu1 and Qu2 is electrically connected to the two connecting lines EL1 and EL2.

[0037] Each of the V-phase switching elements Qv1 and Qv2 is connected in series. Each of the V-phase switching elements Qv1 and Qv2 is connected to the V-phase coil at 23V. Furthermore, the series connection of each of the V-phase switching elements Qv1 and Qv2 is electrically connected to the two connecting lines EL1 and EL2.

[0038] Each of the w-phase switching elements Qw1 and Qw2 is connected in series. Each of the w-phase switching elements Qw1 and Qw2 is connected to the w-phase coil 23w. Furthermore, the series connection of each of the w-phase switching elements Qw1 and Qw2 is electrically connected to the two connecting lines EL1 and EL2.

[0039] The converter device 30 includes a control unit 37. The control unit 37 controls the switching operations of each switching element Qu1 to Qw2. The control unit 37 can be implemented, for example, by one or more dedicated hardware circuits and / or one or more processors (control circuits) that operate according to computer programs (software). The processor includes a CPU and memories such as RAM and ROM, which store, for example, program codes or instructions configured to enable the processor to perform various processes. Memory, or computer-readable medium, includes all usable media accessible by a general-purpose or special-purpose computer.

[0040] The control unit 37 is electrically connected to the air conditioning ECU 13 via connector 27. Based on commands from the air conditioning ECU 13, the control unit 37 periodically switches each switching element Qu1 to Qw2 on / off. Specifically, the control unit 37 performs pulse width modulation (PWM) control on each switching element Qu1 to Qw2 based on commands from the air conditioning ECU 13. More specifically, the control unit 37 generates a control signal using a carrier signal and a command voltage value signal (comparison object signal). Furthermore, the control unit 37 converts DC power into AC power by using the generated control signal to control the ON / OFF state of each switching element Qu1 to Qw2.

[0041] <Noise Reduction Section 36>

[0042] The noise reduction unit 36 ​​includes a common-mode choke 38 and a smoothing capacitor 39. The smoothing capacitor 39 and the common-mode choke 38 together form a low-pass filter circuit 40. The low-pass filter circuit 40 is disposed on the connection lines EL1 and EL2. The low-pass filter circuit 40 is electrically disposed between the connector 27 and the converter circuit 35. The common-mode choke 38 is disposed on the two connection lines EL1 and EL2.

[0043] A smoothing capacitor 39 is disposed on the converter circuit 35 side relative to the common-mode choke 38. The smoothing capacitor 39 is an X capacitor connected in parallel with respect to the converter circuit 35. The smoothing capacitor 39 is electrically connected to two connection lines EL1 and EL2. Furthermore, the common-mode choke 38 and the smoothing capacitor 39 constitute an LC resonant circuit. Therefore, the low-pass filter circuit 40 of this embodiment is an LC resonant circuit including the common-mode choke 38.

[0044] The noise reduction unit 36 ​​includes two Y capacitors 41. The two Y capacitors 41 are connected in series. The two Y capacitors 41 are grounded to the vehicle body via the converter housing 31 and the casing 14. The two Y capacitors 41 are disposed on the converter circuit 35 side relative to the common-mode choke 38. The two Y capacitors 41 are connected in parallel relative to the common-mode choke 38. The two Y capacitors 41 are connected in parallel relative to the smoothing capacitor 39. The two Y capacitors 41 are located between the common-mode choke 38 and the smoothing capacitor 39.

[0045] The common-mode choke 38 suppresses the propagation of high-frequency noise generated on the vehicle side to the converter circuit 35 of the electric compressor 11. The common-mode choke 38 uses leakage inductance as normal inductance. Therefore, the common-mode choke 38 is used as the L component in the low-pass filter circuit (LC filter) 40 for removing normal-mode noise (differential-mode noise). That is, the common-mode choke 38 can handle both common-mode noise and normal-mode noise (differential-mode noise). Therefore, in the electric compressor 11 of this embodiment, instead of using separate common-mode and normal-mode (differential-mode) choke coils, a common-mode choke 38 is used to handle both modes of noise.

[0046] <Common Mode Choke 38>

[0047] like Figure 3 and Figure 4 As shown, the common-mode choke 38 has a core 50, a first winding 51, and a second winding 52. The core 50 is annular. The core 50 is formed of a strongly magnetic material. For example, the core 50 is formed of a ferrite core. The core 50 has a first core portion 53, a second core portion 54, a first connecting portion 55, and a second connecting portion 56.

[0048] like Figure 4 As shown, the first core 53 and the second core 54 extend in a straight line. The first core 53 and the second core 54 are, for example, quadrangular prisms. The first core 53 and the second core 54 extend parallel to each other. Therefore, the first core 53 and the second core 54 are arranged such that the direction in which the axis of the first core 53 extends coincides with the direction in which the axis of the second core 54 extends. The first core 53 and the second core 54 are separate from each other and face each other. A first winding 51 is wound on the first core 53. A second winding 52 is wound on the second core 54. Therefore, the first winding 51 and the second winding 52 are wound on the core 50. The second winding 52 faces the first winding 51.

[0049] The first connecting portion 55 is, for example, a quadrangular prism. The first connecting portion 55 connects the first end of the first core 53 to the first end of the second core 54. The second connecting portion 56 is, for example, a quadrangular prism. The second connecting portion 56 connects the second end of the first core 53 to the second end of the second core 54. A portion of the first winding 51 and a portion of the second winding 52 are wound around the first connecting portion 55 and the second connecting portion 56.

[0050] Furthermore, the first connecting portion 55 has a portion where the first winding 51 and the second winding 52 are not wound around each other, and the surface of the first connecting portion 55 is exposed. In the first connecting portion 55, the first winding 51 and the second winding 52 are wound around each other with most of the surface of the first connecting portion 55 exposed. Therefore, the first connecting portion 55 is an exposed portion where the surface of the core 50 is exposed without the first winding 51 and the second winding 52 being wound around each other.

[0051] Furthermore, the second connecting portion 56 has a portion where the surface of the second connecting portion 56 is exposed without the first winding 51 and the second winding 52 being wound around it. In the second connecting portion 56, the first winding 51 and the second winding 52 are wound around it with most of their surface exposed. Therefore, the second connecting portion 56 is an exposed portion where the surface of the core 50 is exposed without the first winding 51 and the second winding 52 being wound around it.

[0052] Furthermore, resin components (not shown) are provided between the core 50 and the first winding 51, and between the core 50 and the second winding 52. The resin components ensure insulation between the core 50 and the first winding 51, and insulation between the core 50 and the second winding 52.

[0053] like Figure 3 As shown, the common-mode choke 38 is disposed between the circuit board 34 and the substrate member 32. The common-mode choke 38 is disposed perpendicular to the direction in which the axis of the first core 53 extends and the axis of the second core 54 extends, and to the opposite direction of the circuit board 34 and the substrate member 32.

[0054] The common-mode choke 38 is positioned relative to the base member 32, with the first winding 51 and the second winding 52 separated by thermal grease (not shown). Heat generated from the first winding 51 and the second winding 52 is transferred to the converter housing S1 side of the base member 32 for heat dissipation. Therefore, the converter housing S1 side of the base member 32 is the heat dissipation surface 31a. Furthermore, the core 50 is separated from the heat dissipation surface 31a of the base member 32.

[0055] The first winding 51 and the second winding 52 wound on the first connecting portion 55 are led out as lead portions 57. Similarly, the first winding 51 and the second winding 52 wound on the second connecting portion 56 are led out as lead portions 58. Furthermore, each lead portion 57, 58 is soldered to the circuit board 34, for example, by inserting it into a through hole 34h in the circuit board 34. Thus, the common-mode choke 38 is electrically connected to the circuit board 34.

[0056] Furthermore, the surface of the core 50 facing the circuit board 34 is designated as the first surface 50a. The surface of the core 50 facing the base member 32 is designated as the second surface 50b. Additionally, the surface of the core 50 that is continuous with both the first surface 50a and the second surface 50b and forms the outer contour of the core 50 is designated as the side surface 50c. The side surface 50c of the core 50 is the side surface of the common-mode choke 38.

[0057] <Damping section 60>

[0058] like Figure 5As shown, the converter device 30 also includes a damping section 60. The damping section 60 is configured to increase the leakage inductance of the common-mode choke 38, forming a magnetic circuit for the leakage flux generated from the common-mode choke 38. The damping section 60 is made of a strongly magnetic metal. The relative permeability of the damping section 60 is, for example, set to be higher than "3". The damping section 60 is, for example, made of iron.

[0059] like Figure 3 and Figure 5 As shown, the damping portion 60 has a damping side portion 61 and a damping bend portion 62. The damping side portion 61 is annular. In this embodiment, the damping side portion 61 is a four-cornered annular shape. The damping side portion 61 has a first wall portion 61a, a second wall portion 61b, a third wall portion 61c, and a fourth wall portion 61d. The first wall portion 61a, the second wall portion 61b, the third wall portion 61c, and the fourth wall portion 61d are flat plates. The first wall portion 61a, the second wall portion 61b, the third wall portion 61c, and the fourth wall portion 61d are elongated plates.

[0060] like Figure 3 As shown, the first wall portion 61a, the second wall portion 61b, the third wall portion 61c, and the fourth wall portion 61d have the same length in the short side direction. The first end of the short side direction of each of the first wall portion 61a, the second wall portion 61b, the third wall portion 61c, and the fourth wall portion 61d is located on the same plane. The second end of the short side direction of each of the first wall portion 61a, the second wall portion 61b, the third wall portion 61c, and the fourth wall portion 61d is located on the same plane. The first end of the short side direction of each of the first wall portion 61a, the second wall portion 61b, the third wall portion 61c, and the fourth wall portion 61d forms the top end 61e of the damping side portion 61.

[0061] The length of the long side of the first wall portion 61a is the same as the length of the long side of the second wall portion 61b. The length of the long side of the third wall portion 61c is slightly longer than the length of the long side of the fourth wall portion 61d. The lengths of the long side of the first wall portion 61a and the second wall portion 61b are longer than the length of the long side of the third wall portion 61c.

[0062] The first wall portion 61a and the second wall portion 61b extend parallel to each other. The thickness direction of the first wall portion 61a is the same as the thickness direction of the second wall portion 61b. The third wall portion 61c and the fourth wall portion 61d extend parallel to each other. The thickness direction of the third wall portion 61c is the same as the thickness direction of the fourth wall portion 61d. The first end of the long side of the third wall portion 61c is connected to the first end of the long side of the first wall portion 61a. The second end of the long side of the third wall portion 61c is connected to the first end of the long side of the second wall portion 61b. Therefore, the third wall portion 61c connects the first end of the long side of the first wall portion 61a to the first end of the long side of the second wall portion 61b. The first end of the long side of the fourth wall portion 61d is connected to the second end of the long side of the first wall portion 61a. The second end of the fourth wall portion 61d in the long side direction faces the second end of the second wall portion 61b in the long side direction with a small gap 61s between them.

[0063] like Figure 5 As shown, the damping side portion 61 covers the side surface 50c of the core 50. The first wall portion 61a extends along the side surface of the first core portion 53. The second wall portion 61b extends along the side surface of the second core portion 54. The third wall portion 61c extends along the side surface of the first connecting portion 55. The fourth wall portion 61d extends along the side surface of the second connecting portion 56. Therefore, the damping side portion 61 covers the side surface of the common-mode choke 38.

[0064] like Figure 3 and Figure 5 As shown, the damping portion 60 is fixed to the base member 32 with its top end 61e of the damping side portion 61 in contact with the heat dissipation surface 31a of the base member 32 via a heat dissipation grease (not shown). Therefore, the damping side portion 61 is thermally coupled to the heat dissipation surface 31a of the converter housing 31.

[0065] The damping bend 62 bends from the damping side 61. Specifically, the damping bend 62 bends from the top end 61e of the damping side 61. The damping bend 62 is flat. The damping bend 62 is elongated. The damping portion 60 has a pair of damping bends 62. One of the pair of damping bends 62 bends from the first end in the short side direction of the third wall portion 61c toward the fourth wall portion 61d. The other of the pair of damping bends 62 bends from the first end in the short side direction of the fourth wall portion 61d toward the third wall portion 61c. The long side direction of each damping bend 62 is consistent with the long side direction of the third wall portion 61c and the fourth wall portion 61d. The length of the long side direction of each damping portion 60 is slightly shorter than the length of the long side direction of the fourth wall portion 61d.

[0066] like Figure 5As shown, each damping bend 62 bends from the top end 61e of the damping side 61 toward the common mode choke 38. One of the pair of damping bends 62 is located between the first connecting portion 55 and the heat dissipation surface 31a. The other of the pair of damping bends 62 is located between the second connecting portion 56 and the heat dissipation surface 31a. Therefore, each damping bend 62 is located between the exposed portion and the heat dissipation surface 31a. Furthermore, each damping bend 62 is thermally coupled to the heat dissipation surface 31a. Therefore, the damping portion 60 of this embodiment has a flat plate-shaped damping bend 62 that bends from the damping side 61 and is thermally coupled to the heat dissipation surface 31a. Each damping bend 62 makes surface contact with the heat dissipation surface 31a through a heat dissipation grease (not shown).

[0067] like Figure 6 As shown, the damping section 60 is formed by bending a sheet of material. The first wall section 61a is bent relative to the third wall section 61c along the first bending line K1. The second wall section 61b is bent relative to the third wall section 61c along the second bending line K2. The fourth wall section 61d is bent relative to the first wall section 61a along the third bending line K3. One of the pair of damping bends 62 is bent relative to the third wall section 61c along the fourth bending line K4. The other of the pair of damping bends 62 is bent relative to the fourth wall section 61d along the fifth bending line K5.

[0068] [The Role of the Implementation Method]

[0069] Next, the function of this embodiment will be explained.

[0070] Figure 7 This is a graph showing the frequency characteristics of the low-pass filter circuit 40 relative to the incoming constant-mode noise. Furthermore, Figure 7 The solid line shows the frequency characteristics with the damping section 60. Figure 7 The double-dotted line indicates the frequency characteristics without the damping section 60. The resonant frequency f0 (cutoff frequency) of the low-pass filter circuit 40 is set lower than the frequency of the carrier signal, i.e., the carrier frequency f1. Furthermore, the carrier frequency f1 can be considered as the switching frequency of each switching element Qu1 to Qw2.

[0071] like Figure 7 As shown by the double-dotted line, the Q value of the low-pass filter circuit 40 is relatively high in the absence of the damping section 60. Therefore, the normal-mode noise at frequencies close to the resonant frequency f0 of the low-pass filter circuit 40 is difficult to reduce by the noise reduction section 36.

[0072] On the other hand, in this embodiment, since the damping part 60 is present, therefore... Figure 7 As shown by the solid line, the Q value of the low-pass filter circuit 40 decreases. Therefore, the normal-mode noise at frequencies close to the resonant frequency f0 of the low-pass filter circuit 40 is also reduced by the noise reduction section 36.

[0073] Here, as Figure 7 As shown, the allowable value of the gain (attenuation rate) G required based on vehicle specifications is set as the allowable gain Gth. Furthermore, a specific Q value is set for the gain G of the low-pass filter circuit 40 when the frequency of the constant-mode noise is the same as the resonant frequency f0, which becomes the Q value of the allowable gain Gth. In this configuration, in this embodiment, the damping section 60 lowers the Q value of the low-pass filter circuit 40 than the specific Q value. Therefore, the gain G of the low-pass filter circuit 40 when the frequency of the constant-mode noise is the same as the resonant frequency f0 is smaller than the allowable gain Gth (but larger in absolute value). In other words, the damping section 60 is configured to make the Q value of the low-pass filter circuit 40 lower than the aforementioned specific Q value.

[0074] The leakage inductance of the common-mode choke 38 is increased due to the presence of the damping section 60. Therefore, the resonant frequency f0 of the low-pass filter circuit 40 in this embodiment is lower compared to the case without the damping section 60. Thus, as... Figure 7 As shown, the gain G in the frequency band higher than the resonant frequency f0 is smaller compared to the case without damping section 60. Therefore, the constant-mode noise in the frequency band higher than the resonant frequency f0 can be reduced more appropriately.

[0075] By allowing leakage flux to flow within the damping section 60, eddy currents are generated within the damping section 60. The eddy currents generated within the damping section 60 are thermally converted by the damping section 60. Therefore, the damping section 60 functions as an impedance relative to the leakage flux.

[0076] Furthermore, the heat generated in the damping section 60 is transferred from the top end 61e of the damping side 61 to the heat dissipation surface 31a. Moreover, the heat generated in the damping section 60 is transferred to the heat dissipation surface 31a not only from the top end 61e of the damping side 61, but also from each damping bend 62. Therefore, compared to the case where the damping section 60 does not have each damping bend 62, the heat generated in the damping section 60 is more easily dissipated by the heat dissipation surface 31a.

[0077] [Effects of the Implementation Method]

[0078] The following effects can be obtained from the above embodiments.

[0079] (1) The damping section 60 has a flat, bent portion 62 that bends from the damping side 61 and is thermally coupled to the heat dissipation surface 31a. Therefore, the heat generated in the damping section 60 is transferred to the heat dissipation surface 31a of the converter housing 31 from the damping side 61, in addition to the heat generated in the damping side 61. Thus, compared to the case where the damping section 60 does not have the damping bent portion 62, the heat generated in the damping section 60 is more easily dissipated by the heat dissipation surface 31a. Based on the above, the heat dissipation performance of the damping section 60 can be improved.

[0080] (2) The damping section 60 has a pair of damping bends 62. Therefore, compared with the case where there is only one damping bend 62, the heat generated in the damping section 60 is more easily dissipated by the heat dissipation surface 31a. Thus, the heat dissipation performance of the damping section 60 can be further improved.

[0081] (3) The damping bend 62 bends from the damping side 61 toward the common mode choke 38. For example, consider the case where the damping bend 62 bends from the damping side 61 toward the side opposite to the common mode choke 38. Compared to this case, the overall size of the device, including the common mode choke 38 and the damping part 60, can be made more compact. Therefore, miniaturization of the electric compressor 11 can be achieved.

[0082] (4) For example, consider the case where the damping bend 62 is located between the first winding 51 or the second winding 52 and the heat dissipation surface 31a. In this case, the heat generated from the first winding 51 or the second winding 52 is difficult to transfer to the heat dissipation surface 31a of the converter housing 31 by an amount corresponding to the damping bend 62, thus the heat dissipation performance of the first winding 51 or the second winding 52 deteriorates. Therefore, each damping bend 62 is located between the first connecting portion 55 (which is an exposed portion) and the heat dissipation surface 31a, and between the second connecting portion 56 (which is an exposed portion) and the heat dissipation surface 31a. Thus, even if each damping bend 62 is bent from the top end 61e of the damping side portion 61 toward the common mode choke 38, the heat dissipation performance of the first winding 51 and the second winding 52 will not deteriorate. Therefore, the heat dissipation of the first winding 51 and the second winding 52 can be maintained, and each damping bend 62 bends from the top 61e of the damping side 61 toward the common mode choke 38.

[0083] [Example of Change]

[0084] Furthermore, the above-described embodiments can be modified as follows. The above-described embodiments and the following modifications can be combined with each other within the scope of technical inconsistency.

[0085] like Figure 8 As shown, each damping bend 62 can also be bent from the damping side 61 toward the side opposite to the common-mode choke 38. Therefore, regardless of the placement of the common-mode choke 38, particularly the placement of the first winding 51 and the second winding 52, each damping bend 62 can be bent from the damping side 61 and thermally coupled to the heat dissipation surface 31a. This increases the flexibility in the layout of the damping section 60. Furthermore, heat generated from a portion of the first winding 51 and the second winding 52 wound on the first connecting portion 55, and a portion of the first winding 51 and the second winding 52 wound on the second connecting portion 56, can be easily dissipated to the heat dissipation surface 31a.

[0086] In this embodiment, the number of damping bends 62 is not particularly limited.

[0087] In some embodiments, for example, the damping bend 62 may also be located between the first winding 51 or the second winding 52 and the heat dissipation surface 31a.

[0088] In some embodiments, the damping side 61 may not be a four-cornered ring. For example, the damping side 61 may be a circular ring. In short, the shape of the damping side 61 is not particularly limited as long as it covers at least a portion of the side surface of the common-mode choke 38. Therefore, the damping side 61 may not be a ring; for example, it may be formed solely by the third wall portion 61c.

[0089] In the implementation, the shape of the core 50 is not particularly limited as long as it is annular.

[0090] In one embodiment, the damping portion 60 is formed by bending a sheet of material, but is not limited thereto. The damping portion 60 may also be formed, for example, as a four-cornered cylindrical shape connecting the second wall portion 61b and the fourth wall portion 61d.

[0091] In some embodiments, the first winding 51 and a portion of the second winding 52 may not be wound around the first connecting portion 55.

[0092] In some embodiments, the first winding 51 and a portion of the second winding 52 may not be wound around the second connecting portion 56.

[0093] In some embodiments, the base component 32 may also be in direct contact with the outer surface of the end wall 15a of the suction housing 15 without being separated by heat dissipation grease.

[0094] In this embodiment, the damping portion 60 is fixed to the base member 32 such that the top end 61e of the damping side portion 61 is in direct contact with the heat dissipation surface 31a of the base member 32 without any heat dissipation grease in between. In this case, each damping bend portion 62 is also in direct contact with the heat dissipation surface 31a without any heat dissipation grease in between.

[0095] In one embodiment, the damping portion 60 may also be fixed to the intake housing 15 with the top end 61e of the damping side portion 61 in contact with the heat dissipation surface of the end wall 15a of the intake housing 15 through heat dissipation grease. In this case, each damping bend portion 62 is also in contact with the heat dissipation surface of the end wall 15a of the intake housing 15 through heat dissipation grease.

[0096] In one embodiment, the damping portion 60 may be fixed to the intake housing 15 in such a state that the top end 61e of the damping side portion 61 is in direct contact with the heat dissipation surface of the end wall 15a of the intake housing 15 without being separated by thermal grease. In short, the damping side portion 61 only needs to be thermally coupled to the heat dissipation surface of the converter housing 31 or the housing 14. Furthermore, in this case, each damping bend portion 62 is also in direct contact with the heat dissipation surface of the end wall 15a of the intake housing 15 without being separated by thermal grease.

[0097] In one embodiment, the damping bend 62 may not bend from the top end 61e of the damping side 61. In short, the damping bend 62 may bend from the damping side 61.

[0098] In the embodiments, the compression unit 18 is not limited to the scroll type; for example, it may also be the piston type, the blade type, etc.

[0099] In this embodiment, the electric compressor 11 is used in the vehicle air conditioning system 10, but is not limited thereto. For example, the electric compressor 11 may also be configured to be used in a fuel cell vehicle to compress air, which is supplied as fluid to the fuel cell, by a compression unit 18.

Claims

1. An electric compressor, comprising: The housing, which draws in fluid; A compression section configured to compress the fluid; An electric motor configured to drive the compression unit; and A converter device configured to drive the electric motor. The converter device includes: A converter circuit configured to convert direct current power into alternating current power; A noise reduction unit is provided on the input side of the converter circuit and configured to reduce the common-mode noise and constant-mode noise contained in the DC power input to the converter circuit; and A converter housing, thermally coupled to the casing and housing the converter circuitry and the noise reduction unit. The noise reduction unit includes: Common mode choke; and A smoothing capacitor, together with the common-mode choke, forms a low-pass filter circuit. The common-mode choke has the following characteristics: A ring-shaped core; The first winding, said first winding is wound around the core; and The second winding is wound around the core and faces the first winding. The converter device also includes a damping section, which forms a magnetic circuit for the leakage flux generated from the common-mode choke to increase the leakage inductance of the common-mode choke. The damping part is made of a strongly magnetic metal. The damping portion has a damping side portion that covers at least a portion of the side surface of the common-mode choke. The damping side is thermally coupled to the heat dissipation surface of the converter housing or the housing. The damping section has a flat, bent portion that bends from the damping side and is thermally coupled to the heat dissipation surface. The damping bend is one of a pair of damping bends, and the damping part has the pair of damping bends.

2. An electric compressor, comprising: The housing, which draws in fluid; A compression section configured to compress the fluid; An electric motor configured to drive the compression unit; and A converter device configured to drive the electric motor. The converter device includes: A converter circuit configured to convert direct current power into alternating current power; A noise reduction unit is provided on the input side of the converter circuit and configured to reduce the common-mode noise and constant-mode noise contained in the DC power input to the converter circuit; and A converter housing, thermally coupled to the casing and housing the converter circuitry and the noise reduction unit. The noise reduction unit includes: Common mode choke; and A smoothing capacitor, together with the common-mode choke, forms a low-pass filter circuit. The common-mode choke has the following characteristics: A ring-shaped core; The first winding, said first winding is wound around the core; and The second winding is wound around the core and faces the first winding. The converter device also includes a damping section, which forms a magnetic circuit for the leakage flux generated from the common-mode choke to increase the leakage inductance of the common-mode choke. The damping part is made of a strongly magnetic metal. The damping portion has a damping side portion that covers at least a portion of the side surface of the common-mode choke. The damping side is thermally coupled to the heat dissipation surface of the converter housing or the housing. The damping section has a flat, bent portion that bends from the damping side and is thermally coupled to the heat dissipation surface. The damping bend bends from the damping side toward the common mode choke. The core has: The first core is for winding the first winding; The second core is for winding the second winding; and The exposed portion of the core surface where the first winding and the second winding are not wound. The damping bend is located between the exposed portion and the heat dissipation surface.

3. The electric compressor according to claim 1, The damping bend bends from the damping side toward the side opposite to the common mode choke.

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