JP5531186B2 - Drive circuit integrated electric compressor - Google Patents

Description

  The present invention relates to an electric compressor integrated with a drive circuit in which a motor is incorporated and the motor drive circuit is also integrated, and in particular, a drive capable of efficiently cooling a power semiconductor element provided in the motor drive circuit. The present invention relates to a circuit-integrated electric compressor.

Patent Document 1 discloses a scroll-type electric compressor integrated with a drive circuit in which a motor for driving a compression mechanism section is incorporated and the motor drive circuit is also integrated. In this motor drive circuit, a power semiconductor element is particularly incorporated in the inverter, and the power semiconductor element generates heat. Therefore, in order to ensure normal operation, it is generally preferable to cool the power semiconductor element. Currently used semiconductors, including power semiconductor elements, are usually made of silicon (Si). Since the maximum operating temperature of such a conventional power semiconductor element is about 150 ° C., it is preferably cooled so as not to exceed this temperature. In Patent Document 1, a refrigerant sucked into the compressor is used, This cooling is performed.
JP 2000-291557 A

However, in the method of cooling the power semiconductor element of the motor drive circuit using the suction refrigerant gas as described above, the following problems may occur.
That is, since the suction refrigerant gas may be overheated by the heat of the power semiconductor element, the compression efficiency of the compressor may be reduced. Further, when the intake gas is overheated, the temperature of the compressed gas also rises, which may cause a heat resistance problem in each part inside the compressor, which may reduce the life of the compressor. Furthermore, since the suction gas passes through the heat exchange route formed for cooling the power semiconductor element, the pressure loss in the refrigerant path inside the compressor increases, which may also reduce the compression efficiency.

  An object of the present invention is to pay attention to the problems in the method of cooling the power semiconductor element of the motor drive circuit with the suction refrigerant gas as described above, and basically, without increasing the temperature of the suction refrigerant gas, An object of the present invention is to provide an electric compressor integrated with a drive circuit capable of efficiently cooling a power semiconductor element of a motor drive circuit while suppressing an increase in pressure loss of a path for the purpose.

In order to solve the above-described problems, a drive circuit integrated electric compressor according to the present invention is a drive circuit integrated electric compressor in which a motor drive circuit including a power semiconductor element is integrally incorporated. A power semiconductor element is configured to be cooled with discharged refrigerant gas, and the power semiconductor element is a wide band gap semiconductor element using silicon carbide (SiC), gallium nitride (GaN), or diamond , and the power semiconductor element The circuit board provided with is configured such that the back surface is cooled by the discharged refrigerant gas through the wall of the compressor, and a drive circuit housing that houses the power semiconductor element and the drive circuit is provided in the compressor. built is arranged axially to the motor, by the power semiconductor element is covered with resin, said power semiconductor element Consisting of those wherein the thermal radiation is prevented to Luo other electronic components.
As another aspect, the drive circuit integrated electric compressor according to the present invention is a drive circuit integrated electric compressor in which a motor drive circuit including a power semiconductor element is integrally incorporated. A semiconductor element is configured to be cooled with a discharged refrigerant gas, and the power semiconductor element is a wide band gap semiconductor element using silicon carbide (SiC), gallium nitride (GaN), or diamond, and the power semiconductor element is The provided circuit board is configured such that the back surface is cooled with the discharged refrigerant gas through the wall of the compressor, and the drive circuit housing that houses the power semiconductor element and the drive circuit is built in the compressor. It is disposed in the axial direction with respect to the motor, and a heat shielding member is provided between the power semiconductor element and other electronic components. Consisting of those characterized by.
In other words, the power semiconductor element is cooled by using the refrigerant gas discharged after passing through the compression mechanism portion of the compressor, not by the conventional cooling by the suction refrigerant gas.

  That is, since the discharge refrigerant gas is used for cooling the power semiconductor element, there is a problem with the use of the intake refrigerant gas, that is, the compression efficiency is reduced due to the rise in the temperature of the intake refrigerant gas, and the life of the compressor is reduced due to the increase in the temperature of the compressed gas The problem of an increase in pressure loss due to the intake refrigerant gas passing through the heat exchange route for cooling and a decrease in compression efficiency associated therewith basically disappear. In other words, since the intake refrigerant gas is not used for cooling, the intake refrigerant gas is compressed and the gas temperature before being discharged does not rise as in the conventional structure, so that high compression efficiency is ensured and the compression is performed. This contributes to improvement of the coefficient of performance (COP) of the machine. In addition, since the intake refrigerant gas is compressed in the refrigerant path in the compressor and an increase in gas temperature before being discharged is suppressed, the durability of the compressor is improved and the life is improved. Further, since the suction refrigerant gas does not have to pass through the heat exchange route for cooling as in the conventional structure, the pressure loss of the refrigerant passage in the compressor is reduced. Furthermore, when a neodymium magnet is used for the rotor as a motor with a built-in compressor, the magnet will be demagnetized due to the temperature rise, but when cooling the power semiconductor with a conventional suction refrigerant lotus, the suction refrigerant gas temperature However, in the present invention, since the refrigerant is cooled by the discharged refrigerant gas after passing through the motor, such a problem is solved.

  However, in the present invention, since the discharged refrigerant gas having a temperature higher than that of the intake refrigerant gas is used for cooling the power semiconductor element, the power semiconductor element is cooled only to a higher temperature than the conventional structure. Become. Therefore, it is necessary to use a power semiconductor element having heat resistance, that is, a higher maximum operating temperature.

In order to satisfy this need, the present invention uses a wide band gap semiconductor element as the power semiconductor element. That is, as described above, all semiconductors currently used, including power semiconductors, are made of silicon (Si). In recent years, wide band gap (WBG) power semiconductors have been developed as a semiconductor material that replaces silicon. The conventional Si power semiconductor has a maximum operating temperature of about 150 ° C., whereas the WBG semiconductor is 200 ° C. or higher. Therefore, the discharge refrigerant gas temperature, which is generally the first half of the 100 ° C. range, is sufficiently high. It becomes possible to cool to. And the problem in the case of using the conventional suction | inhalation refrigerant | coolant gas is solved at a stretch by cooling a power semiconductor with discharge refrigerant | coolant gas. As the wide band gap power semiconductor, silicon carbide (SiC), used those using gallium nitride (GaN) or diamond.

  In addition, since such a wide band gap power semiconductor device has a low on-resistance and a small switching loss, the heat generated from the device itself is also small, so that the amount of heat required for cooling is less than that of the Si power semiconductor device. I'll do it. Also from this aspect, it is possible to cool the wide band gap power semiconductor element sufficiently efficiently by cooling with the discharged refrigerant gas.

  In addition, since the wide band gap semiconductor element has a high heat resistance temperature, it is not necessary to create a temperature lower than necessary as a cooling source, so that the total efficiency when viewed as a whole cooling circuit system is improved.

In the drive circuit-integrated electric compressor according to the present invention it need only be configured so that the power semiconductor elements of the motor driving circuit is cooled by the discharge refrigerant gas, specifically, the upper Symbol power semiconductor element is provided on the high thermal conductivity of the circuit board, Ru adopted a form in which the back of the circuit board is configured to be cooled by the discharge refrigerant gas through the wall (wall of the compressor) of the compressor. By using a circuit board made of a material having high thermal conductivity, for example, high thermal conductivity ceramic, the power semiconductor element is cooled with high efficiency through the circuit board.

  In the electric compressor integrated with a drive circuit according to the present invention, the power semiconductor element may be covered with a low thermal conductive resin. Moreover, the form with which the heat shielding member of the low heat conductivity is provided between the said power semiconductor element and other electronic components can be taken. By shielding with such a low thermal conductivity resin or a low thermal conductivity member, heat radiation to other electronic components can be prevented, so temperature rise of other electronic components can be suppressed, and the entire motor drive circuit Furthermore, the reliability of the compressor as a whole is improved.

The type of refrigerant used in the electric compressor integrated with a drive circuit according to the present invention is not particularly limited, and CO ₂ and HFC 1234yf can be used as refrigerants as well as refrigerants generally used conventionally. In the case of a CO ₂ refrigerant, it is used at a higher temperature and pressure, but it can be sufficiently used for cooling the wide band gap semiconductor element as described above. In addition, HFC1234yf, which is a new refrigerant recently announced, can be used sufficiently for cooling power semiconductor elements.

  Moreover, in the electric compressor integrated with a drive circuit according to the present invention, as the discharge refrigerant gas for cooling the power semiconductor element of the drive circuit, for example, after passing through a built-in motor and a compression unit (compression mechanism unit) in this order. The discharge refrigerant gas can be used, the discharge refrigerant gas after passing through the compression unit and the built-in motor in this order can be used, or the discharge refrigerant gas passing through the built-in motor unit after passing through the compression unit (for example, As in the embodiment described later, it is also possible to use a discharge refrigerant gas that passes through a discharge gas passage formed between the stator of the built-in motor and the drive circuit housing after passing through the compression section.

  The drive circuit integrated electric compressor according to the present invention is particularly suitable for a scroll type compressor, for example. That is, in the case of a scroll type compressor, the motor drive circuit can be easily disposed near the path of the discharged refrigerant gas, and the power semiconductor element of the motor drive circuit can be efficiently cooled.

  Furthermore, the drive circuit integrated electric compressor according to the present invention is particularly suitable when the compressor is mounted on a vehicle. An efficient cooling structure of the power semiconductor element can be realized with a simple configuration without substantially increasing the weight. Especially, it is especially suitable when it consists of the compressor provided in the freezing circuit of a vehicle air conditioner.

  According to the electric compressor integrated with a drive circuit according to the present invention, since the power semiconductor element is cooled using the discharged refrigerant gas, the suction refrigerant gas is compressed and discharged as before. Therefore, it is possible to achieve a high compression efficiency and improve the coefficient of performance (COP) of the compressor. In particular, when a wide bandgap power semiconductor element is used as the power semiconductor element, the power semiconductor element can be efficiently cooled using discharged refrigerant gas.

  Further, since the refrigerant gas is compressed and does not raise the gas temperature before being discharged, the durability and life of the compressor can be improved. Furthermore, since the suction refrigerant gas does not have to pass through the heat exchange route for cooling as in the conventional structure, the pressure loss can be reduced.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a drive circuit integrated electric compressor 100 according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a drive circuit housing, 2 denotes a compressor housing, and 3 denotes a suction housing. In this embodiment, the suction housing 3 includes a stator 4, a rotor 5, and a motor winding 6. A motor 13 is built in. By this motor 13, the drive shaft 7 rotatably supported by the bearing 23 is rotationally driven, and the compression part 8 (compression mechanism part) is operated. Compressing unit 8 is composed of, for example, the disk B Lumpur type.

  A refrigerant gas path as shown by an arrow is formed in the compressor 100, and the refrigerant gas is sucked from the suction port 9 formed in the suction housing 3, passes through the motor unit, and is compressed by the compression unit 8. Then, the ink is discharged from the discharge port 10 formed in the drive circuit housing 1 to the external circuit. Reference numeral 11 denotes a sealed terminal A, and 12 denotes a sealed terminal B. The lead wire 24 and the power from the motor drive circuit 30 are fed to the motor 13.

  The motor drive circuit 30 has a power semiconductor element 15, and the power semiconductor element 15 is provided on the power circuit board 14. In the present embodiment, a wide band gap power semiconductor element is used as the power semiconductor element 15. The power circuit board 14 is fixed to a wall 26 in the drive circuit housing 1 where the discharged refrigerant gas passes through the insulating material 16, and the power circuit board 14 uses the discharged refrigerant gas passing through the discharge chamber 25. The power semiconductor element 15 on 14 is cooled. In order to increase the cooling efficiency, the power circuit board 14 and further the insulating material 16 are made of ceramics having high thermal conductivity.

  Reference numeral 17 denotes a control circuit board for controlling the motor drive circuit 30, and a microcontroller 18 constituting the control circuit is provided on the control circuit board 17. Power is supplied from an external power source via the connector 22, and then is supplied to the motor drive circuit 30 via the noise filter 20 and the smoothing capacitor 19. These circuit parts are covered with a lid 21 and are blocked from the outside. Further, in this embodiment, the power circuit board 14 is provided with an insulating resin 27 having a low thermal conductivity, and the power semiconductor element 15 is covered with the resin 27 so that heat from the power semiconductor element 15 to other electronic components is covered. Radiation is prevented. In addition, 28 in FIG. 1 has shown the volt | bolt which connects each housing.

  The motor drive circuit 30 and its control circuit are configured, for example, as shown in FIG. In FIG. 2, the electric compressor 100 is provided with the motor drive circuit 30 as described above, and the output from the motor drive circuit 30 is fed to each motor winding 6 of the built-in motor 13 via the sealing terminal 11. As a result, the motor 13 is rotationally driven, and compression by the compression unit 8 is performed. Electric power from an external power source 42 (for example, a battery) is supplied to the motor drive circuit 30 through the high voltage connector 22, and the inverter is connected through the noise filter 20 in which the coil and the capacitor are incorporated, and the smoothing capacitor 19. 41, and the direct current from the power source 42 is converted into a pseudo three-phase alternating current by the inverter 41 and then supplied to the motor 13. For example, a signal for controlling the compressor is supplied to the motor control circuit 45 from the air conditioning control device 44 of the vehicle via the control signal connector 43. The inverter 41 is provided with a total of six power semiconductor elements 15 including three Schottky barrier diodes SiC-SBD 47 and SiC-MOSFET 46 which are wide band gap semiconductors. The same motor drive circuit and control circuit can be used also in the drive circuit integrated electric compressors according to the second and third embodiments described later.

  In the present embodiment configured as described above, the power semiconductor element 15 is efficiently cooled as follows. As described above, the conventional Si power semiconductor has a maximum operating temperature of about 150 ° C., whereas the wide band gap power semiconductor is 200 ° C. or higher. It is possible to sufficiently cool even at a discharge refrigerant gas temperature that is the temperature of Therefore, an increase in the intake refrigerant gas temperature due to the conventional cooling method can be prevented, and the compression efficiency can be improved. Further, the life of each part in the compressor can be improved by suppressing the rise in the intake refrigerant gas temperature. Further, it is not necessary to form a special gas path for cooling the power semiconductor element by the sucked refrigerant gas, so that the pressure loss can be reduced.

  In addition, as described above, since the wide band gap power semiconductor has a low on-resistance of the element and a small switching loss, the heat generated from the element itself is small, so that the amount of heat for cooling is less than that of the Si power semiconductor. I'll do it. Therefore, even the discharged refrigerant gas can be sufficiently cooled.

  Further, as in the present embodiment, the power semiconductor element 15 is covered with the resin 27 having low thermal conductivity, so that, for example, the electronic component mounted on the control circuit board 17, the smoothing capacitor 19, and the noise filter 20 On the other hand, heat radiation can be eliminated, temperature rise can be prevented, and proper operation of these electronic components can be ensured. Although illustration is omitted, it is also effective to partition the power semiconductor element 15 and the control circuit board 17 with a heat shielding plate.

  Further, in the structure of the present embodiment, it is not necessary to consider the route of the intake refrigerant gas, and the position of the intake port 9 is not limited, so that the degree of freedom in design is increased and the attachment to the vehicle is facilitated.

  Further, as described above, since the wide band gap semiconductor element has a high heat resistance temperature, it is not necessary to create a low temperature more than necessary as a cooling source, so that the total efficiency of the cooling circuit system is improved. Further, when the motor 13 uses a neodymium magnet for the rotor, the magnet is demagnetized due to the temperature rise, but when the power semiconductor element is cooled by the conventional suction refrigerant gas, the suction refrigerant gas temperature is increased by heat exchange. However, since there is a possibility that the magnet is demagnetized because it passes through the motor, this problem is also solved.

  FIG. 3 shows a drive circuit integrated electric compressor 200 according to the second embodiment of the present invention. In the present embodiment, the refrigerant gas sucked from the suction port 9 is directly introduced into the compression unit 8 through the suction gas chamber 31, passes through the motor 13, cools the power semiconductor element 15, and is discharged from the discharge port 10. It has become so. Since the magnet of the motor 13 is exposed to the discharged refrigerant gas, it is preferable to use a ferrite magnet or the like having a low temperature demagnetization characteristic instead of a neodymium magnet having a high temperature demagnetization characteristic. In addition, it is also preferable to use a motor (such as an induction motor or a switched reluctance motor) that does not have to worry about demagnetization. Other configurations are the same as those in the first embodiment.

  In such a configuration, since the intake refrigerant gas directly enters the compression unit 8 before passing through the motor 13, it is not heated. Therefore, the compression efficiency can be further improved. Further, since the suction refrigerant gas directly enters the compression section 8 without passing through the motor 13, no pressure loss occurs during this period.

  FIG. 4 shows a drive circuit integrated electric compressor 300 according to a third embodiment of the present invention. In the present embodiment, the drive circuit is mounted in the radial direction of the motor 13, and the discharged refrigerant gas discharged from the compression unit 8 is discharged gas passage 33 formed between the stator 4 of the motor 13 and the drive circuit housing 32. Then, the power semiconductor element 15 of the motor drive circuit is cooled. A drive circuit is incorporated in the drive circuit housing 32, and the motor 13 is incorporated in the drive circuit housing 32. A compression unit 8 is incorporated in the suction housing 3, and the suction refrigerant gas enters the suction gas chamber 26 and is sent to the compression unit 8. Other configurations are the same as those in the first embodiment.

  In such a configuration, while the excellent cooling effect of the power semiconductor element 15 is obtained, the axial length of the electric compressor 300 is shortened, and the mounting property to the vehicle is improved.

  1, 3, and 4 each show a structure in which a power semiconductor element is mounted on a circuit board having high thermal conductivity, although not shown, a discrete type wide band gap power semiconductor element Needless to say, the same effect can be obtained by directly attaching to the wall of the compressor.

  The structure of the electric compressor integrated with a drive circuit according to the present invention can be applied to any electric compressor incorporating a power semiconductor element, and is particularly suitable for a compressor mounted on a vehicle, particularly a compressor for a vehicle air conditioner. is there.

It is a schematic longitudinal cross-sectional view of the drive circuit integrated electric compressor which concerns on the 1st embodiment of this invention. It is a circuit diagram of the motor drive circuit and control circuit in the compressor of FIG. It is a schematic longitudinal cross-sectional view of the drive circuit integrated electric compressor which concerns on the 2nd embodiment of this invention. It is a schematic longitudinal cross-sectional view of the drive circuit integrated electric compressor which concerns on the 3rd embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drive circuit housing 2 Compression part housing 3 Suction housing 4 Stator 5 Rotor 6 Motor winding 7 Drive shaft 8 Compression part 9 Inlet 10 Discharge port 11, 12 Sealing terminal 13 Motor 14 Power circuit board 15 Power semiconductor element 16 Insulating material 17 Control circuit board 18 Microcontroller 19 Smoothing capacitor 20 Noise filter 21 Cover 22 Connector 23 Bearing 24 Lead wire 25 Discharge chamber 26 Wall 27 Resin 28 Bolt 30 Motor drive circuit 31 Suction gas chamber 32 Drive circuit housing 33 Discharge gas passage 41 Inverter 42 External Power supply 43 Control signal connector 44 Air conditioning control device 45 Motor control circuit 46 SiC-MOSFET
47 SiC-SBD
100, 200, 300 Drive circuit integrated electric compressor

Claims (13)

In an electric compressor integrated with a drive circuit in which a motor drive circuit including a power semiconductor element is integrated, the power semiconductor element of the drive circuit is configured to be cooled with discharged refrigerant gas, and the power semiconductor element is carbonized. A wide bandgap semiconductor element using silicon (SiC), gallium nitride (GaN) or diamond , and the circuit board provided with the power semiconductor element has a refrigerant gas discharged from the back through the compressor wall. The power semiconductor element is configured to be cooled, and a drive circuit housing that houses the power semiconductor element and the drive circuit is disposed in an axial direction with respect to a built-in motor in the compressor, and the power semiconductor element is covered with resin. by driving circuit, wherein the heat radiation is prevented from the power semiconductor element to other electronic components Integrated electric compressor. The drive circuit integrated electric compressor according to claim 1, wherein the resin covering the power semiconductor element is a low thermal conductive resin having a lower thermal conductivity than the circuit board. In an electric compressor integrated with a drive circuit in which a motor drive circuit including a power semiconductor element is integrated, the power semiconductor element of the drive circuit is configured to be cooled with discharged refrigerant gas, and the power semiconductor element is carbonized. A wide bandgap semiconductor element using silicon (SiC), gallium nitride (GaN) or diamond , and the circuit board provided with the power semiconductor element has a refrigerant gas discharged from the back through the compressor wall. A drive circuit housing configured to be cooled and housing the power semiconductor element and the drive circuit is disposed in an axial direction with respect to a built-in motor in the compressor, and the power semiconductor element and other electronic components An electric compressor integrated with a drive circuit , wherein a heat shielding member is provided between the two . The drive circuit integrated electric compressor according to claim 3, wherein the heat shielding member is a heat shielding member having a low thermal conductivity lower than that of the circuit board. The drive circuit integrated electric compressor according to claim 1, wherein the circuit board is made of ceramic. Using the refrigerant is CO _2, the drive circuit-integrated electric compressor according to any one of claims 1-5. The drive circuit integrated electric compressor according to any one of claims 1 to 5 , wherein the refrigerant used is HFC1234yf. The drive circuit integrated electric compression according to any one of claims 1 to 7 , wherein the discharge refrigerant gas for cooling the power semiconductor element of the drive circuit is the discharge refrigerant gas after passing through the built-in motor and the compression unit in this order. Machine. The drive circuit integrated electric compression according to any one of claims 1 to 7 , wherein the discharge refrigerant gas for cooling the power semiconductor element of the drive circuit is the discharge refrigerant gas after passing through the compression section and the built-in motor in this order. Machine. The drive circuit integrated electric compression according to any one of claims 1 to 7 , wherein the discharge refrigerant gas for cooling the power semiconductor element of the drive circuit is a discharge refrigerant gas that passes through the internal motor unit after passing through the compression unit. Machine. The drive circuit integrated electric compressor according to any one of claims 1 to 10 , comprising a scroll type compressor. The drive circuit integrated electric compressor according to any one of claims 1 to 11 , comprising a compressor mounted on a vehicle. The drive circuit integrated electric compressor according to any one of claims 1 to 12 , comprising a compressor provided in a refrigeration circuit of a vehicle air conditioner.

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