Composite device

Abstract

The invention provides a composite device which contributes to miniaturization of a vehicle air conditioner and the like, prevents damage caused by surge voltage of a switching element used for power supply and the like in the composite device, and suppresses increase of switching loss. In a composite device having a refrigerant compression function and a heating medium heating function, the switching frequency of second switching elements (Q7, Q8) of a heater control circuit for controlling an electric heater for heating a heating medium is lower than the switching frequency of first switching elements (Q1-Q6) of a motor drive circuit for driving an electric motor for driving a compression mechanism. The switching speed of the second switching elements (Q7, Q8) is slower than the switching speed of the first switching elements (Q1-Q6), and the parasitic inductance of the wiring associated with the first switching elements (Q1-Q6) is smaller than the parasitic inductance of the wiring associated with the second switching elements (Q7, Q8).

Description

Technical Field

[0001] The present invention relates to a composite device having a refrigerant compression function and a heat medium heating function. Background Art

[0002] Patent document 1 describes a vehicle air conditioning device that can be applied to hybrid vehicles, electric vehicles and other vehicles. The vehicle air conditioning device described in Patent document 1 has a refrigerant circuit, which includes: an electric compressor that compresses the refrigerant; a radiator that dissipates heat from the refrigerant discharged from the electric compressor to heat the air supplied to the vehicle compartment; an expansion valve that decompresses and expands the refrigerant after heat dissipation; and a heat exchanger that is equivalent to an evaporator that exchanges heat between the decompressed and expanded refrigerant and the outside air. In addition, in order to assist the radiator in heating the vehicle compartment, the vehicle air conditioning device described in Patent document 1 is equipped with a heat medium heating electric heater that heats the heat medium, and a heat medium-air heat exchanger that heats the air supplied to the vehicle compartment with the heated heat medium. Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent Publication No. 2014-213765 Summary of the invention Problems to be Solved by the Invention

[0004] The vehicle air conditioning device described in Patent Document 1 can supplement the insufficient heating capacity of the radiator. However, in the vehicle air conditioning device described in Patent Document 1, an electric compressor, a heat medium heating electric heater, etc. are separately provided. Therefore, the overall device is large-scale, and there is room for improvement in terms of installation space, etc.

[0005] An object of the present invention is to provide a composite device that can contribute to miniaturization of a vehicle air conditioner or the like, and that prevents damage to a switching element used for power supply or the like due to a surge voltage and suppresses an increase in switching loss in the composite device. Means for solving problems

[0006] According to one aspect of the present invention, a composite device having a refrigerant compression function and a heat medium heating function is provided. The composite device includes: a compressor housing, which internally accommodates a compression mechanism for compressing the refrigerant and an electric motor for driving the compression mechanism, and has a refrigerant inlet for allowing the refrigerant to flow into the interior and a refrigerant outlet for allowing the refrigerant compressed by the compression mechanism to flow out to the outside; a heater housing, which internally accommodates an electric heater for heating the heat medium, and has a heat medium inlet for allowing the heat medium to flow into the interior and a heat medium outlet for allowing the heat medium heated by the electric heater to flow out to the outside; and a circuit housing, which internally accommodates a circuit substrate on which an electronic circuit is installed, and the electronic circuit includes a motor drive circuit for driving the electric motor and a heater control circuit for controlling the electric heater. The compressor housing, the heater housing, and the circuit housing are integrally combined. In addition, the motor drive circuit and the heater control circuit each include a switch element. Furthermore, the switching frequency of the switching element of the heater control circuit is set to be lower than the switching frequency of the switching element of the motor drive circuit, the switching speed of the switching element of the heater control circuit is set to be slower than the switching speed of the switching element of the motor drive circuit, and the electronic circuit is formed so that the parasitic inductance of the wiring connected to the switching element of the motor drive circuit is smaller than the parasitic inductance of the wiring connected to the switching element of the heater control circuit. Effects of the Invention

[0007] According to the present invention, a composite device can be provided that contributes to miniaturization of a vehicle air conditioner, etc. In addition, according to the present invention, damage to a switching element used for power supply, etc., caused by a surge voltage can be prevented in the composite device, and an increase in switching loss can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a front view of the composite device according to the embodiment. Figure 2 It is a right side view of the composite device according to the embodiment. Figure 3 It is a top view of the composite device according to the embodiment. Figure 4 is a partial schematic cross-sectional view of the composite device of the embodiment, which is equivalent to Figure 2 FIG. 20 is an AA cross-sectional view of the embodiment of the present invention. Figure 5 1 is a diagram showing a configuration example of a main part of an electronic circuit including a motor drive circuit and a heater control circuit of a composite device according to an embodiment. Figure 6 is a partial schematic cross-sectional view of the composite device of the embodiment, which is equivalent to Figure 3 FIG. BB cross-sectional view. Figure 7 This is a block diagram showing a schematic configuration of a control system of a composite device according to an embodiment. Figure 8 It is a diagram showing an example of a wiring pattern of a circuit board on which the electronic circuit is mounted. DETAILED DESCRIPTION

[0009] Embodiments of the present invention will be described below with reference to the drawings.

[0010] Figure 1 to Figure 4 The schematic configuration of the composite device 1 according to the embodiment of the present invention is shown. Figure 1 is a front view of the composite device 1 according to the embodiment, Figure 2 is a right side view of the composite device 1 according to the embodiment, Figure 3 is a top view of the composite device 1 according to the embodiment, Figure 4 is a partial schematic cross-sectional view of the composite device of the embodiment, Figure 2 FIG. 20 is an AA cross-sectional view of the embodiment of the present invention.

[0011] The combined device 1 of the embodiment has a refrigerant compression function for compressing the refrigerant and a heat medium heating function for heating a heat medium different from the refrigerant. That is, the combined device 1 has a configuration in which a refrigerant compressor and a heat medium heating device are integrated.

[0012] The composite device 1 can be applied to a vehicle air conditioning device as described above. That is, the composite device 1 can be assembled to a refrigerant circuit in which a refrigerant circulates, and a heat medium circuit in which a heat medium circulates through a pump unit composed of an electric pump or the like. For example, the refrigerant compression function unit of the composite device 1 can be configured to be assembled to the refrigerant circuit, compress the refrigerant after passing through an expansion valve and an evaporator (or a heat exchanger equivalent thereto), and supply the compressed refrigerant to a radiator (refrigerant-air heat exchanger) that heats the air supplied to the vehicle compartment. In addition, the heat medium heating function unit of the composite device 1 can be configured to be assembled to the heat medium circuit, heat the heat medium after passing through a heat medium-air heat exchanger that heats the air supplied to the vehicle compartment, and supply the heated heat medium to the heat medium-air heat exchanger. In addition, the refrigerant and the heat medium can be arbitrarily selected, for example, a gas refrigerant can be used as the refrigerant, and a liquid can be used as the heat medium. In addition, although there is no particular limitation, water (including water mixed with antifreeze, etc.) is generally used as the heat medium. Therefore, the heat medium heating function (heat medium heating device) can also be called a water heating function (water heating device).

[0013] Reference Figure 1 to Figure 4The composite device 1 includes a housing 2. The housing 2 of the composite device 1 includes a first housing 2A, a second housing 2B, a third housing 2C, a first cover 2D, a second cover 2E, and a third cover 2F, which are integrally connected (fastened) by fastening members such as bolts (not shown).

[0014] The first housing 2A is formed into a substantially cylindrical shape. A compression mechanism 3 for compressing the refrigerant and an electric motor 4 for driving the compression mechanism 3 are accommodated in series along the axial direction inside the first housing 2A. Although not particularly limited, the compression mechanism 3 may be a scroll compression mechanism including a fixed scroll and a movable (rotating) scroll. In addition, an output shaft 4a of the electric motor 4 is connected to the compression mechanism 3 (for example, the movable (rotating) scroll).

[0015] One of the two opening ends of the first housing 2A ( Figure 1 , Figure 2 The lower opening end in the middle (i.e., the opening end on the compression mechanism 3 side of the first shell 2A) is closed by the first cover 2D. In addition, the first shell 2A that accommodates the compression mechanism 3 that compresses the refrigerant and the electric motor 4 that drives the compression mechanism 3 can also be called a "compressor shell".

[0016] The second housing 2B is disposed on the side of the first housing 2A. The second housing 2B is formed in a substantially rectangular cylindrical shape. An electric heater 5 for heating a heat medium is accommodated inside the second housing 2B.

[0017] One of the two opening ends of the second housing 2B ( Figure 1 , Figure 2 The lower open end in the middle is closed by the second cover 2E. In addition, the second housing 2B that accommodates the electric heater 5 that heats the heat medium can also be called a "heater housing".

[0018] The third housing 2C is formed in a box shape with an open upper surface. A motor drive circuit 20 for driving (controlling) the electric motor 4 and a heater control circuit 30 for controlling the electric heater 5 are housed inside the third housing 2C. Specifically, in this embodiment, a circuit substrate 6 on which an electronic circuit including the motor drive circuit 20 and the heater control circuit 30 is mounted is housed inside the third housing 2C.

[0019] The bottom wall 7 of the third housing 2C closes the other opening end of the first housing 2A ( Figure 1 , Figure 2 The upper opening end in the middle) is the opening end of the first housing 2A on the electric motor 4 side and the other opening end of the second housing 2B ( Figure 1 , Figure 2The upper opening end of the first housing 2A is formed in the bottom wall 7 of the third housing 2C. Thus, the interior of the first housing 2A is separated from the interior of the third housing 2C, and the interior of the second housing 2B is separated from the interior of the third housing 2C. That is, the bottom wall 7 of the third housing 2C has a first partition 71 that separates the interior of the first housing 2A from the interior of the third housing 2C, and a second partition 72 that separates the interior of the second housing 2B from the interior of the third housing 2C.

[0020] The upper surface (open end) of the third housing 2C is closed by the third cover 2F. In addition, the third housing 2C that accommodates the motor drive circuit 20 and the heater control circuit 30 (specifically, the circuit substrate 6 on which the electronic circuits including these are mounted) can also be called a "circuit housing" or a "substrate housing".

[0021] In the combined device 1 , the refrigerant compression function (electric compressor) is mainly realized by the compression mechanism 3 , the electric motor 4 and the motor driving circuit 20 , and the heat medium heating function (heat medium heating device) is mainly realized by the electric heater 5 and the heater control circuit 30 .

[0022] The first shell 2A is provided with a refrigerant inlet 8 for allowing the refrigerant circulating in the refrigerant circuit to flow into the interior. The refrigerant to flow in is, for example, a refrigerant that has passed through an expansion valve and an evaporator (or a heat exchanger equivalent thereto), that is, a low-temperature and low-pressure refrigerant. In the present embodiment, the refrigerant inlet 8 is provided at a portion of the first shell 2A on the third shell 2C side, that is, near a first partition 71 that separates the interior of the first shell 2A from the interior of the third shell 2C. Preferably, the refrigerant inlet 8 is configured to allow the refrigerant circulating in the refrigerant circuit to flow into the first shell 2A so that at least a portion of the refrigerant flows along the first partition 71.

[0023] The (low-temperature and low-pressure) refrigerant that flows into the first housing 2A through the refrigerant inlet 8 flows in the first housing 2A and is sucked into the compression mechanism 3. The refrigerant sucked into the compression mechanism 3 is compressed by the compression mechanism 3 to become a high-temperature and high-pressure refrigerant, and is discharged from the compression mechanism 3. The discharged (high-temperature and high-pressure) refrigerant flows out from the refrigerant outlet 9 formed in the first housing 2A and is supplied to the above-mentioned radiator (refrigerant-air heat exchanger), for example.

[0024] In the present embodiment, the refrigerant outlet 9 is provided at a position on the first cover 2D side of the first housing 2A, that is, at a position extending from the refrigerant inlet 8 to the first cover 2D side. Figure 1 , Figure 2 Therefore, in the present embodiment, the refrigerant flowing into the first shell 2A from the refrigerant inlet 8 is moved from the first shell 2A to the position away from the vertical direction. Figure 1 , Figure 2The flow is from the upper side to the lower side.

[0025] Furthermore, the first partition 71 can be cooled by the (low-temperature and low-pressure) refrigerant flowing into the first housing 2A via the refrigerant inlet 8. In addition, the electric motor 4 can be cooled by the refrigerant flowing inside the first housing 2A. Furthermore, the refrigerant inlet 8, the interior of the first housing 2A, and the refrigerant outlet 9 constitute a part of the refrigerant circuit.

[0026] The second housing 2B is provided with a heat medium inlet 10 for allowing the heat medium circulating in the heat medium circuit to flow into the interior. The heat medium flowing in is, for example, the heat medium after passing through the heat medium-air heat exchanger, that is, the low-temperature heat medium. In the present embodiment, the heat medium inlet 10 is provided at a portion of the second housing 2B on the third housing 2C side, that is, near the second partition 72 that partitions the interior of the second housing 2B from the interior of the third housing 2C. Figure 1 The inner side of Figure 2 Preferably, the heat medium inlet 10 is configured to allow the heat medium circulating in the heat medium circuit to flow into the second housing 2B so that at least a portion of the heat medium flows along the second partition portion 72 .

[0027] The (low-temperature) heat medium that flows into the second housing 2B through the heat medium inlet 10 flows in the second housing 2B and is heated by the electric heater 5. The heated heat medium flows out from the heat medium outlet 11 formed in the second housing 2B and is supplied to the heat medium-air heat exchanger, for example.

[0028] In the present embodiment, the heat medium outlet 11 is provided near the second partition 72 that partitions the interior of the second housing 2B from the interior of the third housing 2C. Figure 1 Near the front side ( Figure 2 Therefore, in this embodiment, the heat medium that flows into the second housing 2B from the heat medium inlet 10 flows along the second partition 72 in the second housing 2B. Figure 2 , Figure 4 That is, in the combined device 1, the flow direction of the heat medium and the flow direction of the refrigerant are substantially orthogonal.

[0029] The second partition 72 can be cooled by the (low-temperature) heat medium flowing into the second housing 2B through the heat medium inlet 10. The heat medium inlet 10, the interior of the second housing 2B, and the heat medium outlet 11 constitute a part of the heat medium circuit.

[0030] Here, although not shown in the figure, the power supply line from the motor drive circuit 20 to the electric motor 4 and the power supply line from the heater control circuit 30 to the electric heater 5 extend through the bottom wall 7 of the third housing 2C in an airtight and liquid-tight state.

[0031] Next, the motor drive circuit 20 that drives the electric motor 4 and the heater control circuit 30 that controls the electric heater 5 will be described. Figure 5 1 is a diagram showing a configuration example of a main part of the electronic circuit including the motor drive circuit 20 and the heater control circuit 30 .

[0032] In the present embodiment, the motor drive circuit 20 is configured to drive (control) the electric motor 4 by converting a DC voltage from a high voltage power source HV such as a high voltage battery mounted on the vehicle into a three-phase AC voltage and supplying it to the electric motor 4. In addition, the heater control circuit 30 is configured to control the temperature of the electric heater 5 by controlling the application of the high voltage power source HV to the electric heater 5 (power supply between the high voltage power source HV and the electric heater 5). In addition, in the present embodiment, the electronic circuit includes a smoothing capacitor SC that smoothes the DC voltage from the high voltage power source HV.

[0033] like Figure 5 As shown, in the electronic circuit, a smoothing capacitor SC is connected between a power line (HV+) and a ground line (HVGND) of a high voltage power source HV. The smoothing capacitor SC smoothes the DC voltage supplied from the high voltage power source HV to the motor drive circuit 20 and the heater control circuit 30.

[0034] The motor drive circuit 20 includes a first power module 21 and a first driver 22. In addition, a state including the smoothing capacitor SC may be referred to as the motor drive circuit 20.

[0035] The first power module 21 includes six power switching elements (hereinafter referred to as "first switching elements") Q1 to Q6 and six diodes D1 to D6. Although not particularly limited, the first switching elements Q1 to Q6 can be IGBTs (insulated gate bipolar transistors). The first power module 21 converts the DC voltage from the high voltage power supply HV into a three-phase AC voltage by PWM controlling the first switching elements Q1 to Q6, and supplies it to the electric motor 4.

[0036] Specifically, the first power module 21 includes a U-phase arm, a V-phase arm, and a W-phase arm that are provided in parallel with each other between a power line of the high voltage power source HV and a ground line.

[0037] Two first switching elements Q1 and Q2 are connected in series to the U-phase arm, and diodes D1 and D2 are connected in antiparallel to the first switching elements Q1 and Q2 , respectively.

[0038] Two first switching elements Q3 and Q4 are connected in series to the V-phase arm, and diodes D3 and D4 are connected in antiparallel to the first switching elements Q3 and Q4 , respectively.

[0039] Two first switching elements Q5 and Q6 are connected in series to the W-phase arm, and diodes D5 and D6 are connected in antiparallel to the first switching elements Q5 and Q6 , respectively.

[0040] In addition, the intermediate points of the U, V, and W phase arms are connected to the other ends of the U, V, and W phase coils of the electric motor 4 connected in star shape at their respective ends. That is, the intermediate point of the first switching elements Q1 and Q2 of the U phase arm is connected to the U phase coil, the intermediate point of the first switching elements Q3 and Q4 of the V phase arm is connected to the V phase coil, and the intermediate point of the first switching elements Q5 and Q6 of the W phase arm is connected to the W phase coil.

[0041] Therefore, the first power module 21 controls the ratio of the on-period of the first switching elements Q1, Q3, Q5 on the power line side of each phase arm to the on-period of the first switching elements Q2, Q4, Q6 on the ground line side (PWM control), thereby being able to convert the DC voltage from the high-voltage power supply HV smoothed by the smoothing capacitor SC into a three-phase AC voltage and supply it to the electric motor 4, thereby being able to drive the electric motor 4 and the compression mechanism 3.

[0042] The first driver 22 drives (gates of) the first switching elements Q1 to Q6 to turn on / off (switch) according to a control signal (PWM signal) from the control unit 15 described later.

[0043] That is, in the present embodiment, the operation of the motor drive circuit 20 (switching operation of the first switching elements Q1 to Q6 ) and further the operation of the electric motor 4 and the compression mechanism 3 (ie, the refrigerant compression function) are controlled by the control unit 15 .

[0044] The heater control circuit 30 includes a second power module 31 and a second driver 32 .

[0045] The second power module 31 includes two switching elements (hereinafter also referred to as "second switching elements") Q7 and Q8 for controlling the application of the high voltage power supply HV to the electric heater 5. The second switching elements Q7 and Q8 can be IGBTs similarly to the first switching elements Q1 to Q6 of the motor drive circuit 20. In the present embodiment, the second switching element Q7 of one of the two second switching elements Q7 and Q8 is arranged on the output side (voltage side) of the high voltage power supply HV relative to the electric heater 5, and the second switching element Q8 of the other is arranged on the ground side of the high voltage power supply HV relative to the electric heater 5.

[0046] The second power module 31 controls the second switching elements Q7 and Q8 (PWM control) to turn on / off the power supply between the high voltage power supply HV and the electric heater 5 , thereby controlling the temperature of the electric heater 5 and further controlling the temperature of the heat medium heated by the electric heater 5 .

[0047] The second driver 32 , like the first driver 22 of the motor drive circuit 20 , drives (gates of) the second switching elements Q7 and Q8 to turn on / off (switches) according to the control signal (PWM signal) from the control unit 15 .

[0048] That is, in the present embodiment, the control unit 15 controls the operation of the heater control circuit 30 (the second switching elements Q7 and Q8 ), thereby controlling the operation of the electric heater 5 (heat medium heating function).

[0049] Here, refer to Figure 6 The arrangement structure of the smoothing capacitor SC, the first switching elements Q1 to Q6 of the motor drive circuit 20 , and the second switching elements Q7 and Q8 of the heater control circuit 30 will be described. Figure 6 is a partial schematic cross-sectional view of the composite device 1 (equivalent to Figure 3 BB cross-sectional view).

[0050] As described above, the electronic circuit including the motor drive circuit 20 and the heater control circuit 30 (and further the smoothing capacitor SC) is mounted on the circuit board 6 and stored in the third storage space S3. Figure 6 As shown, the circuit substrate 6 is, for example, mounted on a plurality of substrate mounting portions 12 provided in the third storage space S3. In the present embodiment, the plurality of substrate mounting portions 12 are respectively formed into bosses protruding upward (away from the first housing 2A and the second housing 2B) from the bottom wall 7 of the third housing 2C, and the circuit substrate 6 is mounted on the upper surfaces of the plurality of substrate mounting portions 12 by screws 13.

[0051] In the present embodiment, the smoothing capacitor SC, the first switching elements Q1 to Q6 of the motor drive circuit 20 , and the second switching elements Q7 and Q8 of the heater control circuit 30 are arranged at positions where they can be cooled by the refrigerant flowing into the first housing 2A from the refrigerant inlet 8 .

[0052] Specifically, the smoothing capacitor SC, the first switching elements Q1 to Q6 of the motor drive circuit 20, and the second switching elements Q7 and Q8 of the heater control circuit 30 are mounted on the lower surface (the surface on the side of the bottom wall 7 of the third housing 2C) of the circuit substrate 6 mounted on the substrate mounting portion 12, and are arranged to be in thermal contact with the first partition 71 that partitions the interior of the first housing 2A from the interior of the third housing 2C. Here, the so-called "thermal contact with the first partition 71" means being in a state where heat exchange can be performed with the first partition 71, including direct contact with the first partition 71, proximity to the first partition 71 to the extent that heat exchange can be performed, and indirect contact with the first partition 71 via a heat exchange component with high thermal conductivity.

[0053] Figure 7 1 is a block diagram showing a schematic configuration of a control system of the composite device 1 according to the embodiment. Figure 7 As shown, in the present embodiment, an operation request for the refrigerant compression function (including a start request and a stop request), an operation request for the heat medium heating function (including a start request and a stop request), etc. are input from a higher-level control device (for example, a control device for the above-mentioned vehicle air conditioning device) to the control unit 15 of the composite device 1.

[0054] The control unit 15 also receives detection results from various detection units, such as a first temperature detection unit 51 for detecting the temperatures of the first switching elements Q1 to Q6 or values ​​related thereto, and a second temperature detection unit 52 for detecting the temperatures of the second switching elements Q7 and Q8 or values ​​related thereto.

[0055] Furthermore, the control unit 15 is configured to supply a control signal corresponding to the action request input from the upper control device and / or the detection results of the various detection units to the first driver 22 and / or the second driver 32, thereby controlling the action of the first switching elements Q1 to Q6 (i.e., the action of the motor drive circuit 20) and / or the second switching elements Q7, Q8 (i.e., the action of the heater control circuit 30).

[0056] However, the wiring of the electronic circuit, that is, the wiring pattern on the circuit substrate 6, has parasitic inductance. The parasitic inductance of the wiring tends to increase as the length of the wiring increases. In addition, in the electronic circuit, if the parasitic inductance of the wiring between the smoothing capacitor SC and each of the first switching elements Q1 to Q6 of the motor drive circuit 20 and the second switching elements Q7 and Q8 of the heater control circuit 30 is set to L, the surge voltage △V generated when each switching element is switched (turned off) becomes △V = L × di / dt. Here, "di / dt" is the slope of the current flowing through the switching element, which depends on the switching (turning off) speed of the switching element.

[0057] In order to effectively operate the switching element, it is preferred to increase the switching speed of the switching element. However, if the switching speed is increased, "di / dt" increases and the surge voltage △V also rises. If the surge voltage △V exceeds the withstand voltage of the switching element, it will cause damage to the switching element. Therefore, the switching speed of multiple switching elements used in the same circuit is usually limited by the parasitic inductance of the wiring associated with the switching element located at the farthest position from the smoothing capacitor (with the longest wiring length). That is, for switching elements other than the switching element located at the farthest position from the smoothing capacitor, the switching speed is set to be slower in the same way as the switching element located at the farthest position from the smoothing capacitor. Therefore, the switching loss increases more than necessary overall.

[0058] That is, there is a problem that it is difficult to operate all the switching elements efficiently and prevent damage to the switching elements due to the surge voltage.

[0059] The composite device 1 according to the embodiment adopts the following configuration to address the above-mentioned problems.

[0060] (1) First, the driving frequency (switching frequency) of the second switching elements Q7 and Q8 of the heater control circuit 30 is set lower than the driving frequency (switching frequency) of the first switching elements Q1 to Q6 of the motor drive circuit 20 .

[0061] The motor drive circuit 20 (first switching elements Q1 to Q6) converts the DC voltage from the high voltage power supply HV into a three-phase AC voltage. If the switching frequency of the first switching elements Q1 to Q6 is reduced, distortion may occur in the output waveform. If distortion occurs in the output waveform, the electric motor 4 cannot be operated stably. Therefore, the switching frequency of the first switching elements Q1 to Q6 of the motor drive circuit 20 has to be increased to a certain extent. For example, the switching frequency of the first switching elements Q1 to Q6 needs to be a frequency of kHz or higher.

[0062] On the other hand, the heater control circuit 30 (the second switching elements Q7 and Q8) turns on and off the power supply between the high voltage power supply HV and the electric heater 5, so the switching frequency of the second switching elements Q7 and Q8 does not need to be so high. For example, the switching frequency of the second switching elements Q7 and Q8 is sufficient to be a frequency of Hz level.

[0063] Therefore, in the present embodiment, the switching frequency of the second switching elements Q7 and Q8 is set lower than the switching frequency of the first switching elements Q1 to Q6 .

[0064] (2) Next, the switching speed of the second switching elements Q7 and Q8 of the heater control circuit 30 is made slower than the switching speed of the first switching elements Q1 to Q6 of the motor drive circuit 20 .

[0065] If the switching speed of the switching element is slowed down, "di / dt" becomes smaller. Therefore, the surge voltage △V generated when the switching element is switched (turned off) is reduced. Therefore, by slowing down the switching speed of the switching element, it is possible to prevent the surge voltage △V generated when switching (turning off) from exceeding the withstand voltage of the switching element, that is, it is possible to prevent the switching element from being damaged by the surge voltage. However, if the switching speed of the switching element is slowed down, the switching loss increases (the efficiency decreases).

[0066] Here, as described in (1) above, in the present embodiment, the switching frequency of the second switching elements Q7 and Q8 of the heater control circuit 30 is set to be lower than the switching frequency of the first switching elements Q1 to Q6 of the motor drive circuit 20. That is, the second switching elements Q7 and Q8 are switched less frequently than the first switching elements Q1 to Q6. This means that even if the switching speed of the second switching elements Q7 and Q8 is slowed down, the increase in switching loss can be reduced compared to the case where the switching speed of the first switching elements Q1 to Q6 is slowed down, that is, the increase in switching loss as a whole can be suppressed.

[0067] Therefore, in the present embodiment, the switching speed of the second switching elements Q7 and Q8 is set to be slower than the switching speed of the first switching elements Q1 to Q6. Although not particularly limited, in the present embodiment, the gate resistors (not shown) of the second switching elements Q7 and Q8 have a higher resistance value than the gate resistors (not shown) of the first switching elements Q1 to Q6 of the motor drive circuit 20, and thus, the switching speed of the second switching elements Q7 and Q8 is slower than the switching speed of the first switching elements Q1 to Q6.

[0068] (3) Furthermore, in the electronic circuit, the parasitic inductance of the wiring related to the first switching elements Q1 to Q6 of the motor drive circuit 20 is smaller than the parasitic inductance of the wiring related to the second switching elements Q7 and Q8 of the heater control circuit 30 .

[0069] As described in (2) above, in this embodiment, the switching speed of the second switching elements Q7 and Q8 is set to be slower than the switching speed of the first switching elements Q1 to Q6. Therefore, the "di / dt" of the second switching elements Q7 and Q8 is smaller than the "di / dt" of the first switching elements Q1 to Q6. This means that when the surge voltage △V (=L×di / dt) is taken into account, the parasitic inductance of the wiring associated with the second switching elements Q7 and Q8 can be larger than the parasitic inductance of the wiring associated with the first switching elements Q1 to Q6. In other words, even if the parasitic inductance of the wiring associated with the second switching elements Q7 and Q8 is larger than the parasitic inductance of the wiring associated with the first switching elements Q1 to Q6, the surge voltage △V generated when the second switching elements Q7 and Q8 are switched (turned off) can be made not to exceed the withstand voltage of the second switching elements Q7 and Q8.

[0070] Therefore, in the present embodiment, the electronic circuit is formed so that the parasitic inductance of the wiring related to the first switching elements Q1 to Q6 of the motor drive circuit 20 is smaller than the parasitic inductance of the wiring related to the second switching elements Q7 and Q8 of the heater control circuit 30 .

[0071] The shorter the wiring length, the smaller the parasitic inductance of the wiring. Therefore, in the electronic circuit of this embodiment, the smoothing capacitor SC is arranged closer to the first switching elements Q1 to Q6 of the motor drive circuit 20 than the second switching elements Q7 and Q8 of the heater control circuit 30 (see Figure 5 ), whereby the length of the wiring associated with the first switching elements Q1 to Q6 (specifically, the wiring between the smoothing capacitor SC and the first switching elements Q1 to Q6) is shorter than the length of the wiring associated with the second switching elements Q7 and Q8 (specifically, the wiring between the smoothing capacitor SC and the second switching elements Q7 and Q8).

[0072] In addition, the wider the width of the wiring (the thicker the wiring), the smaller the parasitic inductance of the wiring. Therefore, in the electronic circuit of the present embodiment, the wiring associated with the first switching elements Q1 to Q6 is formed to be wider (thicker) than the wiring associated with the second switching elements Q7 and Q8. However, in the present embodiment, the wiring associated with the second switching elements Q7 and Q8 includes a common portion with the wiring associated with the first switching elements Q1 to Q6. Therefore, in the present embodiment, the wiring between the smoothing capacitor SC and the first switching elements Q1 to Q6 ( Figure 5 The wiring enclosed by the dotted line in the figure) is formed as a portion other than the common portion of the wiring between the smoothing capacitor SC and the second switching elements Q7 and Q8, that is, the wiring between the first switching elements Q1 to Q6 and the second switching elements Q7 and Q8 ( Figure 5 The width of the wiring (the wiring enclosed by the single-dot chain line) is wide (thick).

[0073] Specifically, if Figure 8As shown, on the lower surface of the circuit board 6 (the surface on the side of the bottom wall 7 of the third housing 2C), the smoothing capacitor SC is arranged (mounted) at a position closer to the first switching elements Q1 to Q6 of the motor driving circuit 20 than the second switching elements Q7 and Q8 of the heater control circuit 30. In addition, on the upper surface of the circuit board 6 (the surface on the side of the third cover 2F), the length of the wiring patterns P1a and P1b between the smoothing capacitor SC and the first switching elements Q1 to Q6 is shorter than the length of the wiring patterns P1a+P2a and P1b+P2b between the smoothing capacitor SC and the second switching elements Q7 and Q8. Furthermore, the wiring patterns P1a and P1b between the smoothing capacitor SC and the first switching elements Q1 to Q6 are formed to be wider than other wiring patterns on the circuit board 6, for example, the second wiring patterns P2a and P2b between the first switching elements Q1 to Q6 and the second switching elements Q7 and Q8, and the third wiring patterns P3a and P3b extending from the second switching elements Q7 and Q8 toward the electric heater 5.

[0074] According to the composite device 1 of the embodiment, the following effects can be obtained.

[0075] The composite device 1 of the embodiment includes: a first housing (compressor housing) 2A, which accommodates a compression mechanism 3 for compressing a refrigerant and an electric motor 4 for driving the compression mechanism 3, and has a refrigerant inlet 8 and a refrigerant outlet 9; a second housing (heater housing) 2B, which accommodates an electric heater 5 for heating a heat medium, and has a heat medium inlet 10 and a heat medium outlet 11; and a third housing (circuit housing) 2C, which accommodates a circuit substrate 6 on which an electronic circuit is mounted, wherein the electronic circuit includes a motor drive circuit 20 for driving the electric motor 4 and a heater control circuit 30 for controlling the electric heater 5. The first housing (compressor housing) 2A, the second housing 2B (heater housing) and the third housing (circuit housing) 2C are integrally combined.

[0076] Such a composite device 1 can function as a refrigerant compressor (electric compressor) for compressing the refrigerant and a heat medium heating device for heating the heat medium, and can heat the heat medium while compressing the refrigerant. Therefore, the composite device 1 can be applied to the above-mentioned vehicle air conditioning device. In addition, by applying the composite device 1 to the vehicle air conditioning device, the vehicle air conditioning device can be miniaturized compared to the conventional structure that separately includes the electric compressor and the heat medium heating device.

[0077] In the composite device 1, the motor drive circuit 20 includes first switching elements Q1 to Q6 that convert a DC voltage into a three-phase AC voltage, and the heater control circuit 30 includes second switching elements Q7 and Q8 that turn on / off the power supply to the electric heater 5. In addition, the switching frequency (driving frequency) of the second switching elements Q7 and Q8 is set to be lower than the switching frequency (driving frequency) of the first switching elements Q1 to Q6, the switching speed of the second switching elements Q7 and Q8 is set to be slower than the switching speed of the first switching elements Q1 to Q6, and the electronic circuit is formed so that the parasitic inductance of the wiring related to the first switching elements Q1 to Q6 is smaller than the parasitic inductance of the wiring related to the second switching elements Q7 and Q8.

[0078] Specifically, in the circuit board 6, the smoothing capacitor SC is arranged at a position closer to the first switching elements Q1 to Q6 of the motor driving circuit 20 than the second switching elements Q7 and Q8 of the heater control circuit 30, and the length of the wiring patterns P1a and P1b between the smoothing capacitor SC and the first switching elements Q1 to Q6 is shorter than the length of the wiring patterns P1a+P2a and P1b+P2b between the smoothing capacitor SC and the second switching elements Q7 and Q8. In addition, the wiring patterns P1a and P1b between the smoothing capacitor SC and the first switching elements Q1 to Q6 are formed to be wider than the width of other wiring patterns on the circuit board 6 including the wiring patterns P2a and P2b between the first switching elements Q1 to Q6 and the second switching elements Q7 and Q8.

[0079] Therefore, the refrigerant compression function and the heat medium heating function are not impaired, and the damage caused by the surge voltage to the first switching elements Q1 to Q6 and the second switching elements Q7 and Q8 can be prevented, and the increase in the switching loss of the first switching elements Q1 to Q6 and the second switching elements Q7 and Q8 can be suppressed. Specifically, for the first switching elements Q1 to Q6, the damage caused by the surge voltage is prevented by reducing the parasitic inductance of the wiring related to them without slowing down the switching speed (without increasing the switching loss). On the other hand, for the second switching elements Q7 and Q8, the damage caused by the surge voltage is prevented by slowing down the switching speed, and the increase in the switching loss is suppressed by reducing the switching frequency. And, thereby, in the composite device 1, it is possible to take into account both the prevention of the damage caused by the surge voltage to the first switching elements Q1 to Q6 and the second switching elements Q7 and Q8 and the suppression of the increase in the switching loss of the first switching elements Q1 to Q6 and the second switching elements Q7 and Q8.

[0080] In addition, in the composite device 1, the refrigerant inlet 8 of the first housing (compressor housing) 2A is arranged in the vicinity of the first partition portion 71 that separates the interior of the first housing (compressor housing) 2A from the interior of the third housing (circuit housing) 2C, and in the third housing (circuit housing) 2C, the smoothing capacitor SC, the first switching elements Q1 to Q6, and the second switching elements Q7 and Q8 are arranged to be in thermal contact with the first partition portion 71.

[0081] Therefore, the smoothing capacitor SC, the first switching elements Q1 to Q6, and the second switching elements Q7 and Q8 are effectively cooled by heat exchange with the first partition 71 that can be cooled by the refrigerant flowing into the first housing (compressor housing). That is, high cooling performance (heat dissipation performance) can be ensured for the smoothing capacitor SC, the first switching elements Q1 to Q6, and the second switching elements Q7 and Q8, and as a result, stable operation of the composite device 1 can be achieved.

[0082] In addition, in the above-mentioned embodiment, the smoothing capacitor SC, the first switching elements Q1 to Q6, and the second switching elements Q7 and Q8 are arranged in thermal contact with the first partition 71. However, this is not limited to this. In the composite device 1, the heat medium inlet 10 of the second housing (heater housing) 2B is provided near the second partition 72 that partitions the inside of the second housing 2B (heater housing) 2B from the inside of the third housing (circuit housing) 2C, and the second partition 72 can be cooled by the heat medium flowing into the second housing 2B. Therefore, the smoothing capacitor SC, the first switching elements Q1 to Q6, and the second switching elements Q7 and Q8 may also be arranged in thermal contact with the second partition 72. Alternatively, a part of the smoothing capacitor SC, the first switching elements Q1 to Q6, and the second switching elements Q7 and Q8 may be arranged in thermal contact with the first partition 71, and the remaining part may be arranged in thermal contact with the second partition 72. Even in this way, the cooling performance (heat dissipation performance) for the smoothing capacitor SC, the first switching elements Q1 to Q6, and the second switching elements Q7 and Q8 can be ensured.

[0083] In the above description, the case where the combined device 1 is applied to a vehicle air conditioner is mainly described. However, the invention is not limited thereto. The combined device 1 can also be applied to various devices and systems using an electric compressor for compressing a refrigerant and a heat medium heating device for heating a heat medium.

[0084] As mentioned above, although embodiment of this invention was demonstrated, this invention is not limited to the said embodiment, It is a matter of course that deformation|transformation and change are possible based on the technical idea of ​​this invention. Description of reference numerals:

[0085] 1: composite device; 2: housing; 2A: first housing (compressor housing); 2B: second housing (heater housing); 2C: third housing (circuit housing); 3: compression mechanism; 4: electric motor; 5: electric heater; 6: circuit board; 8: refrigerant inlet; 9: refrigerant outlet; 10: heat medium inlet; 11: heat medium outlet; 15: control unit; 20: motor drive circuit; 30: heater control circuit; Q1 to Q6: first switching elements (switching elements of the motor drive circuit); Q7, Q8: second switching elements (switching elements of the heater control circuit); SC: smoothing capacitor.

Claims

1. A composite device having a refrigerant compression function and a heat medium heating function, comprising: A compressor housing that accommodates a compression mechanism for compressing a refrigerant and an electric motor for driving the compression mechanism, and has a refrigerant inlet for allowing the refrigerant to flow into the interior and a refrigerant outlet for allowing the refrigerant compressed by the compression mechanism to flow out to the outside; a heater housing that accommodates an electric heater for heating a heat medium and has a heat medium inlet for allowing the heat medium to flow into the interior and a heat medium outlet for allowing the heat medium heated by the electric heater to flow out to the outside; as well as a circuit housing for accommodating a circuit substrate on which an electronic circuit is mounted, wherein the electronic circuit includes a motor drive circuit for driving the electric motor and a heater control circuit for controlling the electric heater, The compressor housing, the heater housing and the circuit housing are integrally combined. The motor drive circuit and the heater control circuit each include a switching element, The switching frequency of the switching element of the heater control circuit is set to be lower than the switching frequency of the switching element of the motor drive circuit. The switching speed of the switching element of the heater control circuit is set to be slower than the switching speed of the switching element of the motor drive circuit. The electronic circuit is formed so that a parasitic inductance of a wiring related to a switching element of the motor drive circuit is smaller than a parasitic inductance of a wiring related to a switching element of the heater control circuit.

2. The composite device according to claim 1, wherein: The switching element of the motor drive circuit is configured to convert a DC voltage from a power supply into an AC voltage. The switch element of the heater control circuit is configured to turn on / off the energization between the power source and the electric heater. The electronic circuit further includes a smoothing capacitor for smoothing a DC voltage from the power supply, In the circuit substrate, the smoothing capacitor is arranged at a position closer to the switching element of the motor drive circuit than the switching element of the heater control circuit.

3. The composite device according to claim 2, wherein: In the circuit substrate, a length of a wiring pattern between the smoothing capacitor and a switching element of the motor drive circuit is shorter than a length of a wiring pattern between the smoothing capacitor and a switching element of the heater control circuit.

4. The composite device according to claim 2, wherein: In the circuit substrate, a width of a wiring pattern between the smoothing capacitor and a switching element of the motor drive circuit is formed to be wider than widths of other wiring patterns.

5. The composite device according to any one of claims 2 to 4, wherein: The interior of the compressor housing is separated from the interior of the circuit housing by a first partition portion, and the refrigerant inlet of the compressor housing is provided near the first partition portion. In the circuit case, the smoothing capacitor, the switching element of the motor drive circuit, and the switching element of the heater control circuit are arranged in thermal contact with the first partition.

6. The composite device according to any one of claims 2 to 4, wherein: The interior of the heater housing is separated from the interior of the circuit housing by a second partition portion, and the heat medium inlet of the heater housing is provided near the second partition portion. In the circuit case, the smoothing capacitor, the switching element of the motor drive circuit, and the switching element of the heater control circuit are arranged in thermal contact with the second partition.

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