JP2012062778A - Electric supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric supercharger reducing a loss and improving efficiency by reducing an inductance in wiring lines, and achieving reduction in size.SOLUTION: The electric supercharger 1 includes: a turbine impeller 10 driven by exhaust gas of an engine; a compressor impeller 20 compressing air and supercharging the engine; a connecting shaft 30 with one end connected to the rotation shaft 11 of the turbine impeller 10 and with the other end connected to the rotation shaft 21 of the compressor impeller 20; a motor 40 composed of a motor stator 401 and a motor rotor 400 fixed to the connecting shaft 30; a controlling device 50 mounted on the outer peripheral wall of a motor housing 104, for converting DC power into AC power and controlling the motor 40; and a cooling device 800 cooling the controlling device 50. In the supercharger, a loss can be decreased by reducing the wiring length.

Description

  The present invention relates to a supercharger that drives a compressor, and to an electric supercharger that incorporates an electric motor.

  In general, a supercharger is composed of a compressor (compressor) and a turbine. The compressor impeller of the compressor and the turbine impeller of the turbine are connected to each other by a connecting shaft, and the turbine impeller is driven by engine exhaust gas to rotate the compressor impeller. The compressor is configured to supercharge the engine by compressing air by rotating a compressor impeller through a connecting shaft. In this supercharger using the exhaust gas of the engine, an electric supercharger having a built-in electric motor for assisting during low-speed rotation with low efficiency has been proposed. The electric motor used here is arranged on a turbine and a compressor shaft, and an increase in supercharging pressure by driving the electric motor or power regeneration by power generation using exhaust energy is performed according to the operating state.

  The rotational speed of the exhaust turbine supercharger is, for example, as high as 100,000 to 200,000 rpm, and the electric motor built in the electric supercharger can be driven to rotate and regenerate at high speed corresponding to this high speed rotation. Desired. For this reason, the inverter which converts the direct current power of the battery mounted in the vehicle into the alternating current power of arbitrary frequencies is required. The problem with the AC power converted by the inverter is that the power loss due to the electrical resistance and inductance of the power supply cable connecting the inverter and the electric turbocharger is large, especially when the frequency is high. It becomes prominent and requires a larger amount of power than the power consumed by the electric motor, which increases the size of the inverter.

  As a countermeasure, for example, in the electric supercharger disclosed in Patent Document 1, the inverter for electrically controlling the motor and the inverter controller are accommodated in a donut-shaped or U-shaped container, and are connected to the compressor housing by a heat insulating connecting member. It is connected. The heat insulation connecting member has an air-cooled or water-cooled heat insulation layer that insulates the high temperature of the compressor discharge air so as not to be transferred to the driver container. Since the electric supercharger is equipped with a motor stator, inverter and inverter controller, the length of the power supply cable connecting the inverter and the electric supercharger can be greatly shortened, and the distance between the electric motor and the inverter is minimized. The electrical resistance and inductance of the power supply cable can be reduced to a negligible level. Moreover, since the inverter is integrated with the electric supercharger, a place for installing the inverter separately is unnecessary.

JP 2007-46479 A

However, in the electric supercharger disclosed in Patent Document 1, since the wiring between the motor and the control device passes through the inside of the compressor, it is necessary to keep the air tight so that air does not leak, and the structure becomes complicated. In addition, since the rotational speed of the electric supercharger reaches 100,000 to 200,000 rpm and its control is also performed at a high frequency, the wiring becomes longer by the amount that passes through the compressor. It will increase. Furthermore, in a control device, semiconductor elements and capacitors generate heat, but there are few heat dissipation paths, the temperature rises remarkably, the guaranteed lifetime of the element is shortened, and current must be suppressed to reduce performance. There is a problem of not becoming. In addition, it is necessary to increase the carrier frequency of the inverter drive corresponding to the high-speed rotation, and for example, it is necessary to use at a switching frequency several times higher than that of a normal inverter device, so that the switching loss is greatly increased. There were also problems specific to electric superchargers.

  In order to reduce such switching loss, it is important to further reduce the inductance of the wiring. When the inductance of the wiring is large, an induced voltage is generated by multiplying the inductance by the current change rate dI / dt. The number of revolutions of the motor of the electric supercharger reaches 100,000 rpm or more, and in order to perform this control, it is necessary to control at a carrier frequency several to ten times that of a normal inverter. In that case, a rise of current that cannot be considered in a normal inverter is required, that is, a large current change rate dI / dt. As for the switching loss, the greater the induced voltage called surge, the greater the loss at switch-off. As described above, in the electric supercharger, it is necessary to realize a switching frequency that is difficult to think normally, but it is difficult to reduce dI / dt, and the switching loss increases. Becomes very important.

  The present invention has been made to solve the above problems, and by improving the cooling performance, the wiring length between the motor and the control device that controls the motor is shortened, the inductance is reduced, The object is to provide an electric supercharger that can be reduced in size with reduced loss and improved efficiency.

  In order to solve the above-mentioned problem, an electric supercharger according to a first aspect of the present invention includes a compressor impeller, a connecting shaft connected to a rotating shaft of the compressor impeller and rotating together with the rotating shaft, and fixed to the connecting shaft. A motor stator that surrounds the motor rotor and is fixed to the motor housing, is attached to an outer peripheral wall portion of the motor housing, converts DC power into AC power, and includes the motor rotor and the motor stator. A control device for controlling the motor and a cooling device for cooling the control device with cooling oil are provided.

  An electric supercharger according to a third aspect of the present invention includes a turbine impeller, a compressor impeller, one end connected to the rotating shaft of the turbine impeller, and the other end connected to the rotating shaft of the compressor impeller. A connecting shaft that rotates together with the rotating shaft, a motor rotor fixed to the connecting shaft, a motor stator that surrounds the motor rotor and fixed to the motor housing, and attached to the outer peripheral wall portion of the motor housing, and the DC power is converted to AC power And a control device that controls the motor composed of the motor rotor and the motor stator, and a cooling device that cools the control device with cooling oil.

  According to the present invention, it is possible to efficiently dissipate heat generated from a semiconductor element and a capacitor by cooling a control device that performs power conversion and motor control with cooling oil. By arranging it on the wall, the length of the wiring between the motor and the control device can be minimized and the inductance due to the wiring can be reduced. As a result, the switching loss of the inverter can be reduced and electric supercharging There is a remarkable effect that the performance of the machine can be improved.

1 is a schematic cross-sectional view showing an entire electric supercharger in Embodiment 1. FIG. FIG. 3 is a schematic diagram showing an example of a cooling path of the cooling device for the electric supercharger in the first embodiment. FIG. 3 is a schematic diagram showing a flow of cooling oil in the electric supercharger in the first embodiment. FIG. 3 is a schematic cross-sectional view showing an example of mounting a semiconductor element of the control device for the electric supercharger in the first embodiment. FIG. 10 is a schematic cross-sectional view showing another example of mounting the semiconductor element of the control device for the electric supercharger in the first embodiment. FIG. 3 is a schematic partial cross-sectional view showing a wiring connection mechanism between the semiconductor element of the electric supercharger and the motor in the first embodiment. 6 is a schematic cross-sectional view showing an arrangement of a control device for an electric supercharger according to Embodiment 2. FIG. FIG. 6 is a schematic cross-sectional view showing an entire electric supercharger in a third embodiment.

  Hereinafter, an electric supercharger according to an embodiment of the present invention will be described with reference to FIGS.

Embodiment 1 FIG.
FIG. 1 is a schematic cross-sectional view showing the entire electric supercharger in the first embodiment. FIG. 2 is a schematic diagram illustrating an example of a cooling path of the electric supercharger in the first embodiment. FIG. 3 is a schematic diagram showing a flow of cooling oil in the electric supercharger in the first embodiment. FIG. 4 is a schematic cross-sectional view showing a mounting example of a semiconductor element of the control device for the electric supercharger in the first embodiment.

  In FIG. 1, an electric supercharger 1 includes a turbine impeller 10 that is driven by wind power of exhaust gas from an engine (not shown), a turbine housing 102 that houses the turbine impeller 10, and supercharges the engine by compressing air. A compressor impeller 20 that houses the compressor impeller 20, a connecting shaft 30 that has one end connected to the rotating shaft 11 of the turbine impeller 10 and the other end connected to the rotating shaft 21 of the compressor impeller 20, Motor 40 composed of motor rotor 400 fixed to shaft 30 and motor stator 401 surrounding motor rotor 400 and fixed to motor housing 104, and DC power attached to the outer peripheral wall portion of motor housing 104 are converted to AC power And a control device for controlling the motor 40 0, the wiring terminal 451 of the wiring of the motor 40, the wiring terminal 551 of the wiring of the control device 50, and the connection mechanism 45 and the connection mechanism 55 in which the wiring terminal 451 and the wiring terminal 551 are connected by fitting. ing.

  Next, the operation of the electric supercharger in the first embodiment will be described with reference to FIG. Since the main body of the present invention is to reduce the loss due to the arrangement of the control device for the electric supercharger and the cooling, the description of the operation around the engine and the inverter circuit is omitted.

  The electric supercharger 1 supercharges a large amount of intake air to the engine to achieve not only high output but also low fuel consumption. The turbine impeller 10 is rotationally driven by the exhaust gas from the engine, and the compressor impeller 20 is driven and rotated by rotating the rotational shaft 21 of the compressor impeller 20 connected by the rotational shaft 11 of the turbine impeller 10 and the connecting shaft 30. Increase the supply pressure. The electric supercharger 1 has a three-phase AC motor 40 (hereinafter referred to as a motor) in which a magnetic field is adjusted by a current flowing in a field winding of a motor stator 401, and rotates a turbine impeller 10 driven by exhaust gas. It is on a connecting shaft 30 connected to the shaft 11 and the rotating shaft 21 of the compressor impeller 20, and the compressor impeller 20 is driven by the motor 40 to increase the supercharging pressure. When a sufficient number of revolutions can be obtained with exhaust gas, power regeneration is performed by power generation using exhaust energy. A battery (not shown) that supplies electric power to the motor 40 is a DC power supply, and for example, electric power is supplied to an inverter circuit including a smoothing capacitor of the control device 50, and is supplied to each of the U phase, V phase, and W phase. The three pairs (six) of power MOSFETs and the pair of (two) power MOSFETs of the field winding are switched based on a control signal from the control circuit to be converted into AC power, and the motor The motor rotor 400 is driven by controlling the electric power supplied to the field winding of the stator 401, and the connecting shaft 30 is rotated to drive the compressor impeller 20 to assist supercharging to the engine.

  The motor rotor 400 is provided between the turbine impeller 10 and the compressor impeller 20 on the shaft 30. Preferably, if the motor rotor 400 is arranged offset to the compressor impeller 20 side, the thermal resistance with the turbine impeller 10 that becomes high temperature can be increased, and the amount of heat received can be reduced. The motor stator 401 is fixed to the motor housing 104 so as to surround the motor rotor 400.

  In addition, the wiring terminal 551 of the control device 50 that controls the motor 40 is electrically connected to the wiring terminal 451 from the motor 40, and the DC power supplied from the battery as the power source is converted into AC power. To be supplied.

  The housing 100 includes a turbine housing 101, a compressor housing 102, and a motor housing 104, and a control device 50 is attached to the motor housing 104. The semiconductor element 70 mounted on the control device 50 uses a semiconductor made of SiC (silicon carbide) having excellent heat resistance. Further, a cooling method using cooling oil is adopted for cooling the control device 50. is doing. Since the exhaust gas of the engine sent to the turbine housing 101 is high in temperature, the heat is transferred to the control device 50, and the temperature of the semiconductor element 70 mounted on the control device 50 is raised. The use of oil cooling, compared with water cooling, which can only be used up to about 100 ° C due to the use of SiC, which is an element, and the use of a cooling system with cooling oil suitable for high temperature cooling Since the possible temperature range is up to about 200 ° C., the heat resistance of the cooler is greatly improved and can be used without problems even when the temperature exceeds 100 ° C. Therefore, it is possible to arrange the control device 50 on the outer peripheral wall surface of the motor housing 104 It became.

  Thereby, the wiring terminal 451 protrudes from the motor 40 in the radial direction, and the wiring terminal 551 also protrudes from the control device 50 in accordance with this, and the wiring terminal 451 of the motor 40 and the wiring terminal 551 of the control device 50 are By means of the connection mechanism 45 and the connection mechanism 55, the wiring terminals 451 and 551 are fitted together, mechanically fixed, and electrically connected. Since the wiring between the motor 40 and the control device 50 is only via the circumferential portion of the motor housing 104 by the wiring terminal 451 and the wiring terminal 551, the wiring length can be shortened with a simple structure, and at a high frequency. In addition, inductance and resistance due to wiring can be reduced, and loss can be reduced. In switching at a high carrier frequency, which is a problem in the electric supercharger, the inductance can be greatly reduced by reducing the wiring length. As a result, the surge voltage during switching is reduced and switching loss can be reduced, which is very effective. Thus, since heat resistance can be improved and a loss can be reduced, the performance and reliability of an electric supercharger can be improved.

  Further, by connecting the wiring terminals 451 and 551 with the connecting mechanisms 45 and 55 by fitting each other, not only the wiring between the motor stator 401 and the control device 50 can be shortened, but also the assembling workability of the wiring connection is greatly increased. There is also an effect that can be improved.

  Next, FIG. 2 shows a cooling path of the cooling device for the electric supercharger. A cooling device for cooling the radiator 801, the pump 802, and the like by cooling all of the objects that require cooling including the control device 50, the housing 100, and the motor 40 by oil cooling and circulating the cooling by the cooling device 800 The cooling effect can be enhanced without increasing. In this case, it is preferable that the cooling path in the cooling device 800 is in order of increasing upper limit temperature. As shown in FIG. 2, the control device 50, the compressor housing 102, the motor 40, and the turbine housing 101 are arranged in this order. It is economical because there is no need to increase heat dissipation unnecessarily.

  An example of the path of the cooling oil flowing through the electric supercharger 1 is shown in FIG. The cooling oil 80 delivered from the pump 802 first circulates in the control device 50 from the inlet 851 of the control device 50 provided on the turbine housing 101 side, cools the semiconductor element 70, the base (substrate) 72, etc. It exits from the outlet 852 of the device 50 and flows into the compressor housing 102 through the inlet 811 close to the control device 50 and circulates in the compressor housing 102 to cool the compressor impeller 20, the compressor rotating shaft 21, and the like. Subsequently, the cooling oil 80 circulates in the motor housing 104 and the motor 40 from the outlet of the compressor housing 102 and the inlet 812 of the motor housing 104 on the side wall of the motor housing 104 opposite to the control device 50, After cooling the motor rotor 400 and the connecting shaft 30, the motor rotor 104 and the inlet of the turbine housing 101 on the side wall on the control device 50 side and the inlet 821 of the turbine housing 101 flow into the turbine housing 101 and circulate in the turbine housing 101. After the turbine rotating shaft 11 and the like are cooled, it is discharged from the outlet 822.

  The cooling oil 80 used here may be a vegetable oil, but is preferably a mineral oil that is difficult to separate from water, and an insulating oil may be used when it is in direct contact with the conductive part. In addition, when it is necessary to remove the control device 50 at the time of a failure or periodic inspection, it is necessary to suppress the oil leakage of the cooling oil 80. However, the operation can be performed by providing the on-off valves V1 and V2 at the inlet 851 and the outlet 852. It can be carried out without impairing the performance.

  When the cooling part of the motor 40 is divided into a plurality of parts, the cooling may be performed by alternately passing through the housing 104 and the cooling part of the motor 40. However, depending on the mounting restrictions in the engine room, this order is not necessarily required, but there is a need to increase the size of the radiator.

  FIG. 4 shows a mounting example of the semiconductor element of the control device. The wiring of the semiconductor element may be wire bonding, but as shown in the embodiment of FIG. 4, the semiconductor element 70 is composed of an insulator 73 formed on a base 72 and a conductive material such as aluminum or copper formed thereon. The body 74 is joined using a joining material 75 such as solder or silver paste. Further, by directly joining the lead 71 as the wiring of the semiconductor element 70 via the bonding material 76, the heat dissipation can be improved and the heat fatigue resistance can be improved, so that the heat resistance is further improved. Can do. In order to cool the semiconductor element 70 and the base 72, the cooling oil 80 is circulated in the space between the base 72 and the control device housing 77.

  When a wiring having a small junction area such as a gate is required, a bump 79 is provided on the gate lead 78 to contact the gate of the semiconductor element 70 as in the example of mounting other semiconductor elements shown in FIG. It is good to have a structure to connect. Further, preferably, the semiconductor element 70 and the gate lead 78 are sealed with a resin material, so that the thermal stress at the joint is reduced and the thermal fatigue resistance can be further improved. When the semiconductor element 70 is sealed, the heat resistance can be improved by using a high heat-resistant resin material in which the Tg of the sealing material is higher than the operating environment temperature.

  In addition, it is desirable to use a material having a thermal expansion coefficient close to that of SiC for the bonding material 76 of the semiconductor element 70 and the lead 71 or the bonding material 75 of the semiconductor element 70 and the base 72 because the thermal fatigue resistance is high. It is better to use Invar material.

  The cooling structure of the control device 50 may be configured such that the semiconductor element 70 or a substrate (base 72) on which the semiconductor element 70 is mounted is provided with a heat sink such as aluminum or copper as a high thermal conductor and the cooling oil 80 as a coolant is allowed to flow. In order to further enhance the cooling effect, it is preferable that the cooling oil 80 is in direct contact with the semiconductor element 70 or the substrate 72 on which the semiconductor element 70 is mounted, and the semiconductor element 70 or the substrate 72 on which the semiconductor element 70 is mounted is placed in a sealed space. It is preferable to provide the cooling oil 80 to flow.

  The wiring terminal 451 of the motor stator 40 is preferably disposed on the side closer to the compressor housing 102 because the temperature is relatively low in the housing 100.

  The control device 50 includes an inverter circuit, and includes an upper arm semiconductor element 702 connected to the positive side of the power source and the motor 40, and a lower arm semiconductor element 701 connected to the negative side of the motor and the power source. The arm semiconductor element 702 and the lower arm semiconductor element 701 are often arranged side by side in the axial direction. As shown in FIG. 6, the semiconductor elements 701 and 702 can be improved in heat resistance by being arranged closer to the compressor having a low temperature.

  The wiring terminal 451 can be most miniaturized in terms of the configuration of the stator core by bringing the end of the wiring to the end of the motor stator 401 in the axial direction. As shown in FIG. 6, the connection mechanisms 45 and 55 may be configured by male and female connectors as a fitting structure, or may be screwed. Further, the wiring terminals 451 and 551 themselves may be provided with the function of the connection mechanisms 45 and 55, for example, a terminal block is provided as the connection mechanism 55 in the control device 50, and the wiring terminal 451 is penetrated as the connection mechanism 45. A hole may be drilled and screwed to the terminal block. The control device 50 may be fixed to the motor housing 104 by the connection mechanisms 45 and 55. However, in order to enhance the earthquake resistance, through holes are provided at four corners of the control device 50, and screw holes are formed in the motor housing 104. The controller 50 may be fixed to the motor housing 104 by being provided and screwed. The mounting position of the control device 50 is preferably on the compressor housing 102 side, which is at a lower temperature. When the control device 50 is disposed above the motor housing 104, the heat of the motor housing 104 may be transferred to the control device 50 by convection, and the temperature of the control device 50 may be increased. It is preferable to arrange it below the housing 104.

  As described above, in the electric supercharger of the supercharger in the first embodiment, the heat generation from the semiconductor element and the capacitor is efficiently dissipated by cooling the control device that performs power conversion and motor control with the cooling oil. By arranging the control device on the outer peripheral wall portion of the motor housing, the length of the wiring between the motor and the control device can be minimized and the inductance due to the wiring can be reduced. There is a remarkable effect that the switching loss of the inverter can be reduced and the performance of the electric supercharger can be improved.

  Note that the motor temperature rises due to the high rotation speed of the motor and the heat resistance of the control device is improved, and when a magnet is used, the output decreases due to demagnetization. By using a motor, resistance to temperature rise can be increased.

Embodiment 2. FIG.
FIG. 7 is a schematic cross-sectional view showing the arrangement of the control device for the electric supercharger in the second embodiment.
As shown in FIG. 7, in the electric supercharger 1 according to the second embodiment, the control device is divided into three parts for each phase of the control devices 50a, 50b, 50c, and each is arranged radially on the outer peripheral wall surface of the motor housing 104. Except for the points provided, the other components are the same as those of the electric supercharger 1 of the first embodiment shown in FIG.

  In the second embodiment, the wiring terminals 451a, 451b, 451c (not shown, similar to 451 in FIG. 6) of the respective phases of the motor stator 401 and the wiring terminals 551a, 551b, 551c of the control devices 50a, 50b, 50c (FIG. 6 are connected to the motor stator 401 side connection mechanisms 45a, 45b, and 45c via the control device 50 side 55a, 55b, and 55c, respectively. Thereby, the wiring length connecting the motor stator 401 and the control device 50 can be shortened, and the loss can be further reduced.

  As described above, in the electric supercharger according to the second embodiment, the control device is divided into three parts in accordance with the three-phase AC phase, and each of them is arranged on the outer peripheral wall portion of the motor housing. By connecting with a long length, there is a remarkable effect that the inductance due to the wiring can be reduced and the loss can be further reduced.

Embodiment 3 FIG.
FIG. 8 is a schematic cross-sectional view showing the entire electric supercharger in the third embodiment.
As shown in FIG. 8, in the electric supercharger 2 according to the third embodiment, the compressor impeller 20 that compresses air to supercharge the engine, the compressor housing 101 that houses the compressor impeller 20, and the rotation of the compressor impeller 20 A motor 40 including a connecting shaft 30 connected to the shaft 21, a motor rotor 400 fixed to the connecting shaft 30, a motor stator 401 surrounding the motor rotor 400 and fixed to the motor housing 104, and an outer peripheral wall of the motor housing 104 The control device 50 that converts the DC power attached to the unit into AC power and controls the motor 40, the wiring terminal 451 of the wiring of the motor 40, the wiring terminal 551 of the wiring of the control device 50, the wiring terminal 451 and the wiring Connection mechanism 45 and connection mechanism connected to terminal 551 by fitting 5 is constituted by the.

  The electric supercharger 2 according to the third embodiment has a three-phase AC motor 40 (hereinafter referred to as a motor) whose magnetic field is adjusted by a current flowing in the field winding of the motor stator 401, and the rotating shaft of the compressor impeller 20. The compressor impeller 20 is driven by the motor 40 to increase the supercharging pressure. As in the first embodiment, a battery (not shown) that supplies power to the motor 40 is a direct current power source. For example, power is supplied to an inverter circuit including a smoothing capacitor of the control device 50, and the U phase, V Three pairs (six) of power MOSFETs connected to each of the phase and W phase, and one pair (two) of power MOSFETs of the field winding are switched based on a control signal from the control circuit. The motor rotor 400 is driven by controlling the power supplied to the field winding of the motor stator 401 by converting to AC power, and the connecting shaft 30 is rotated to drive the compressor impeller 20 to assist supercharging to the engine. I am letting.

  The motor stator 401 is fixed to the motor housing 104 so as to surround the motor rotor 400. In addition, the wiring terminal 551 of the control device 50 that controls the motor 40 is electrically connected to the wiring terminal 451 from the motor 40, and the DC power supplied from the battery as the power source is converted into AC power, and the motor 40.

  Since the details of the connection between the wiring terminal 451 from the motor 40 and the wiring terminal 551 of the control device 50 are the same as those in the first embodiment, the description thereof is omitted.

  The cooling device in the third embodiment is obtained by removing the turbine housing 101 from the cooling path of the cooling device 800 in the first embodiment shown in FIG. 2, and in order to increase the cooling effect, it is preferable to set the upper limit temperature in ascending order. Cooling oil is circulated in the order of the radiator 801, the pump 802, the control device 50, the compressor housing 102, and the motor 40.

  As in the first embodiment, the semiconductor element 70 mounted on the control device 50 uses a semiconductor made of SiC (silicon carbide) having excellent heat resistance. Further, cooling of the control device 50 includes cooling oil. The cooling method using is adopted. The semiconductor element 70 uses SiC, which is a high heat-resistant semiconductor element, and further employs a cooling method using cooling oil suitable for high-temperature cooling, so that heat resistance can be greatly improved. As a result, the control device 50 can be disposed on the outer peripheral wall surface of the motor housing 104.

  As described above, in the electric supercharger according to the third embodiment, it is possible to efficiently dissipate heat generated from the semiconductor elements and capacitors by cooling the control device that performs power conversion and motor control with the cooling oil. By arranging the control device on the outer peripheral wall of the motor housing, the length of the wiring between the motor and the control device can be minimized and the inductance due to the wiring can be reduced. As a result, the switching loss of the inverter Can be reduced and the performance of the electric supercharger can be improved. In addition, since there is no turbine impeller driven by exhaust gas from the engine, there is no increase in temperature due to exhaust gas, so the size of the cooling pump in the cooling system can be reduced, and the electric supercharger can be downsized There is also a remarkable effect of being able to.

  The semiconductor element used in the control device 50 may be a general element based on silicon (Si). In the present invention, silicon such as silicon carbide (SiC), gallium nitride (GaN), or diamond is used. When the so-called wide band gap semiconductor having a wide band gap is applied, a further effect is exhibited. Wide bandgap semiconductors have lower power loss than elements made of silicon semiconductors, so it is possible to increase the efficiency of inverter circuits and control from the viewpoint of reducing wiring inductance and reducing power loss of semiconductor elements. The efficiency of the apparatus 50 can be realized. Further, since the wide band gap semiconductor has a high voltage resistance and a high allowable current density, it is possible to reduce the size of the inverter circuit and the like, and the control device 50 can be reduced in size. In addition, since it has high heat resistance and can operate at a high temperature, it can be installed in the vicinity of the heating element, the heat sink and the like are small, and heat dissipation measures are easy.

  Moreover, in the figure, the same code | symbol shows the same or an equivalent part.

DESCRIPTION OF SYMBOLS 1, 2 Electric supercharger 10 Turbine impeller 11 Turbine rotating shaft 100 Housing 101 Turbine housing 102 Compressor housing 104 Motor housing 20 Compressor impeller 21 Compressor rotating shaft 30 Connection shaft 40 Motor 400 Motor rotor 401 Motor stator 451,551 Wiring terminal 50 70 Semiconductor element 80 Cooling oil 800 Cooling device

Claims (8)

A compressor impeller,
A connecting shaft connected to the rotating shaft of the compressor impeller and rotating together with the rotating shaft;
A motor rotor fixed to the connecting shaft;
A motor stator surrounding the motor rotor and fixed to the motor housing;
A control device that is attached to the outer peripheral wall portion of the motor housing, converts DC power to AC power, and controls a motor constituted by the motor rotor and the motor stator;
A cooling device for cooling the control device with cooling oil;
An electric supercharger characterized by comprising: Turbine impeller,
One end is connected to the rotating shaft of the turbine impeller, the other end is connected to the rotating shaft of the compressor impeller, and a connecting shaft that rotates together with these rotating shafts,
The electric supercharger according to claim 1, comprising:   The turbine impeller is accommodated in a turbine housing, the compressor impeller is accommodated in a compressor housing, and the cooling oil is sequentially circulated in the control device, the compressor housing, the motor housing, and the turbine housing. The electric supercharger according to claim 2.   2. The electric supercharging according to claim 1, wherein the compressor impeller is accommodated in a compressor housing, and the cooling oil is sequentially circulated in the control device, the compressor housing, and the motor housing. Machine.   The said control apparatus is divided | segmented into the number of phases of alternating current power, The said divided | segmented control apparatus is respectively attached to the outer peripheral wall part of the said motor housing. The electric supercharger described.   The electric supercharger according to any one of claims 1 to 5, wherein a wiring terminal provided with the motor and a wiring terminal provided with the control device are connected by fitting.   The electric supercharger according to any one of claims 1 to 6, wherein a semiconductor element used in the control device is formed of a wide band gap semiconductor. The electric supercharger according to claim 7, wherein the wide band gap semiconductor is silicon carbide, gallium nitride, or diamond.

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