JP2021019429A - Vehicle driving system - Google Patents

Abstract

To effectively utilize thermal energy generated by a heating part for generating heat when a rotating electrical machine is driven.SOLUTION: A disclosed vehicle driving system includes: a rotating electrical machine (40); a thermoelectric element (4) that is thermally connected to heating parts (22A and 22B) for generating heat when the rotating electrical machine is driven and that can convert thermal energy to electrical energy; and a first power supply circuit (76) that is electrically connected to the thermoelectric element and that generates a first power supply voltage on the basis of the electrical energy from the thermoelectric element. The rotating electrical machine can be operated on the basis of the first power supply voltage generated by the first power supply circuit.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a vehicle drive device.

A technique for cooling a coil end (an axial end of a stator coil of a rotary electric machine) with oil is known (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2013-172486

However, in the above-mentioned conventional technology, it is difficult to effectively utilize the thermal energy generated in the heat generating portion that generates heat when the rotary electric machine is driven, such as the coil end.

Therefore, on one aspect, it is an object of the present invention to effectively utilize the thermal energy generated in the heat generating portion that generates heat when the rotary electric machine is driven.

On one side, the rotating machine and
A thermoelectric element that is thermally connected to a heat generating part that generates heat when the rotary electric machine is driven and can convert thermal energy into electric energy.
Includes a first power supply circuit that is electrically connected to the thermoelectric element and generates a first power supply voltage based on the electrical energy from the thermoelectric element.
The rotary electric machine is provided with a vehicle drive device that can operate based on the first power supply voltage generated by the first power supply circuit.

On one side, according to the present invention, it is possible to effectively utilize the thermal energy generated in the heat generating portion that generates heat when the rotary electric machine is driven.

It is a figure which shows an example of the whole structure of the motor drive system for an electric vehicle. It is sectional drawing which shows typically the sectional structure of the traveling motor to which the driving device for a vehicle of this Example is applied. It is the schematic which shows an example of the power source composition which concerns on an inverter control device. It is a display figure which shows the power supply form at the time of a fail in the power supply configuration shown in FIG.

Hereinafter, each embodiment will be described in detail with reference to the accompanying drawings.

In the following, first, the outline of the motor drive system 1 including the vehicle drive device of the present embodiment will be described, and then the traveling motor 40 (rotary electric machine) to which the vehicle drive device of the present embodiment is preferably applied. An example) will be described, and then the power supply configuration according to the inverter control device 50 (an example of the control device) will be described. In the following description of FIGS. 1 and 3, the term "connection" between various elements means "electrical connection" unless otherwise noted.

FIG. 1 is a diagram showing an example of the overall configuration of the motor drive system 1 for an electric vehicle. The motor drive system 1 is a system for driving a vehicle by driving a traveling motor 40 using a high-voltage battery 2. As long as the electric vehicle travels by driving the traveling motor 40 using electric power, the details of its method and configuration are arbitrary. The electric vehicle is a concept including a hybrid vehicle whose power source is an engine and a traveling motor 40, and an electric vehicle whose power source is only a traveling motor 40.

As shown in FIG. 1, the motor drive system 1 includes a high-pressure battery 2, a smoothing capacitor 5, an inverter 6, a traveling motor 40 (denoted as “MG” in FIG. 1), and an inverter control device 50. In the example shown in FIG. 1, the configuration of the motor drive system 1 other than the high-voltage battery 2 forms an example of the vehicle drive device.

The high-voltage battery 2 is an arbitrary power storage device that stores electricity and outputs a DC voltage, and may include a capacitive element such as a nickel hydrogen battery, a lithium ion battery, or an electric double-layer capacitor. The high voltage battery 2 is typically a battery having a rated voltage of more than 100V, for example, having a rated voltage of 288V. However, the high voltage battery 2 may be a battery having a lower rated voltage (for example, 48V) used in a so-called mild hybrid vehicle. In the example shown in FIG. 1, as an example, the high voltage battery 2 has a rated voltage of 48 V. In FIG. 1, the high-potential side of the high-voltage battery 2 is indicated by “P”, and the low-potential side (ground side) is indicated by “N”.

The smoothing capacitor 5 is connected in parallel with the inverter 6. The smoothing capacitor 5 is connected between the positive electrode line and the negative electrode line.

The inverter 6 includes U-phase, V-phase, and W-phase arms arranged in parallel with each other between the positive electrode line and the negative electrode line. The U-phase arm includes a switching element connected in series (MOSFET: MOSFET in this example) a field-effect transistor) Q1 and Q2, and the V-phase arm includes a switching element connected in series (MOSFET in this example). The W-phase arm includes Q3 and Q4, and the W-phase arm includes switching elements (MOSFETs in this example) Q5 and Q6 connected in series. Further, diodes D11 to D16 are arranged between the drain and the source of the switching elements Q1 to Q6 so that a current flows from the source side to the drain side, respectively. The diodes D11 to D16 may be MOSFET body diodes. The switching elements Q1 to Q6 may be switching elements other than MOSFETs, such as IGBTs (Insulated Gate Bipolar Transistors).

The traveling motor 40 is a three-phase AC motor, and one ends of three U, V, and W phases coils are commonly connected at a midpoint. The other end of the U-phase coil is connected to the midpoint M1 of the switching elements Q1 and Q2, the other end of the V-phase coil is connected to the midpoint M2 of the switching elements Q3 and Q4, and the other end of the W-phase coil is. It is connected to the midpoint M3 of the switching elements Q5 and Q6.

In the example shown in FIG. 1, the motor drive system 1 includes a single traveling motor 40, but may include an additional motor (including a generator). In this case, the additional motor (s) may be connected to the high voltage battery 2 in parallel with the traveling motor 40 and the inverter 6 together with the corresponding inverter. Further, in the example shown in FIG. 1, the motor drive system 1 does not include a DC / DC converter, but a DC / DC converter may be provided between the high-voltage battery 2 and the inverter 6. In the motor drive system 1, another in-vehicle electric load such as an air conditioner may be connected in parallel with the smoothing capacitor 5.

As shown in FIG. 1, a cutoff switch SW1 for cutting off the power supply from the high-voltage battery 2 is provided between the high-voltage battery 2 and the smoothing capacitor 5. The cutoff switch SW1 may be composed of a semiconductor switch, a relay, or the like. The cutoff switch SW1 is normally on, and is turned off, for example, in a situation where rapid discharge of the smoothing capacitor 5 is required.

FIG. 2 is a cross-sectional view schematically showing a cross-sectional structure of a traveling motor 40 to which the vehicle driving device of the present embodiment is preferably applied. In FIG. 2, an oil channel and a water channel are schematically illustrated. In FIG. 2, the flow of the refrigerant (oil and cooling water) is schematically shown by arrows.

FIG. 2 shows the rotating shaft 12 of the traveling motor 40. In the following description, the axial direction refers to the direction in which the rotation shaft (rotation center) 12 of the traveling motor 40 extends, and the radial direction refers to the radial direction centered on the rotation shaft 12. Therefore, the radial outer side refers to the side away from the rotating shaft 12, and the radial inner side refers to the side toward the rotating shaft 12. Further, the circumferential direction corresponds to the rotation direction around the rotation shaft 12. In FIG. 2, the X direction along the axial direction is shown, and the X1 side and the X2 side are defined. Further, FIG. 2 shows an example in the vertical direction in the mounted state. In the following, the vertical direction corresponds to the vertical direction shown in FIG.

The traveling motor 40 is an inner rotor type and has a motor housing 10. The motor housing 10 non-rotatably supports the stator 21. The motor housing 10 may be composed of a plurality of pieces. In the example shown in FIG. 2, as an example, the motor housing 10 is composed of three pieces 10a to 10c (hereinafter, referred to as "main housing 10a", "inner diameter side housing 10b", and "cover housing 10c", respectively). However, the number of pieces is arbitrary.

The main housing 10a has a tubular shape with an opening in the center in the radial direction, and forms the outermost outer peripheral portion in the radial direction and the cover portion in the axial direction on the X1 side. The main housing 10a forms a water channel 901 at the outer peripheral portion. Cooling water is supplied to the water channel 901 from the X1 side (for example, pumped by a water pump (not shown)). The cooling water is, for example, water containing LLC. The cooling water circulating through the water channel 901 cools the stator 21 from the outside in the radial direction via the oil in the oil channel 801 described later.

The inner diameter side housing 10b has a tubular shape with an opening at the center in the radial direction, and is basically provided inside the main housing 10a (except for the flange portion 11b at the end on the X2 side). The inner diameter side housing 10b directly supports the radial outer surface of the stator 21. In the inner diameter side housing 10b, the outer surface (outer peripheral surface) in the radial direction abuts in the radial direction on the inner surface (inner peripheral surface) in the radial direction of the main housing 10a.

The inner diameter side housing 10b forms an oil passage 801 with the main housing 10a on the outer side of the stator 21 in the radial direction. The oil passage 801 is located on the radial outside of the stator 21, and the oil flowing through the oil passage 801 cools the stator 21 from the radial outside.

Further, the inner diameter side housing 10b has a flange portion 11b extending radially outward at the end portion on the X2 side in the axial direction, and the flange portion 11b is axially opposite to the end portion on the X2 side in the axial direction of the main housing 10a. Abut. The flange portion 11b forms a water channel 902 connected to the water channel 901 of the main housing 10a. The water channel 902 extends in the axial direction.

The cover housing 10c has a disk-like shape when viewed in the axial direction, and forms an axial cover portion on the X2 side. Further, the cover housing 10c has a shaft-shaped portion 11c and an annular protruding portion 11d on the X1 side.

The shaft-shaped portion 11c is inserted into the hollow portion 34A of the rotor shaft 34. It extends concentrically with the rotor shaft 34 on the rotating shaft 12. The outer diameter r2 of the shaft-shaped portion 11c is smaller than the inner diameter r1 of the hollow portion 34A of the rotor shaft 34, and a circle is formed between the radial outside of the shaft-shaped portion 11c and the radial inside of the hollow portion 34A of the rotor shaft 34. An annular space 90 (hereinafter, referred to as “shaft annular space 90”) is formed.

The annular protrusion 11d extends around the rotation shaft 12 concentrically with the rotor shaft 34. That is, the protruding portion 11d is provided in a manner concentrically with the shaft-shaped portion 11c so as to surround the shaft-shaped portion 11c. The protruding portion 11d is formed so as to face the rotor core 32 in the axial direction and partition the bearing 14b and the coil end 22B of the coil (stator coil) 22 in the radial direction.

The cover housing 10c forms radial channels 903 and 906 and axially extending channels 904 and 905.

One end of the radial outer side of the water channel 903 is connected to the water channel 902 of the inner diameter side housing 10b, and the other end of the radial inner side is connected to the water channel 904.

The water channel 904 is formed in the axial portion 11c. The water channel 904 extends in the axial direction, one end on the X2 side is connected to the water channel 903, and the other end on the X1 side opens into the hollow portion 34A.

The water channel 905 is formed in the axial portion 11c. The water channel 905 extends in the axial direction, one end on the X2 side is connected to the water channel 906, and the other end on the X1 side opens into the hollow portion 34A.

One end of the radial inner side of the water channel 906 is connected to the water channel 905, and the other end of the radial outer side is connected to a return water channel (not shown). The return water channel may communicate with a water pump that discharges cooling water to the above-mentioned water channel 901 via a radiator (not shown) or the like.

The cover housing 10c forms an oil passage 810 and an oil passage 814 communicating with a space 92 in which the bearing 14b is located (hereinafter, referred to as a “bearing arrangement space 92”). Specifically, the cover housing 10c forms an oil passage 810 and an oil passage 814 in a region axially opposed to the bearing 14b. The oil passage 810 and the oil passage 814 are formed at positions offset in the circumferential direction with respect to the water passages 903 and 906 formed in the cover housing 10c. The oil passage 810 supplies oil discharged from an oil pump (not shown) to the bearing arrangement space 92. The oil passage 814 is located below the oil passage 810 and forms an oil passage for returning the oil supplied to the bearing arrangement space 92.

The traveling motor 40 includes a stator 21, a rotor 30, and the like in an internal space surrounded by the motor housing 10.

The stator 21 is provided so as to surround the radial outer side of the rotor 30. The outer side of the stator 21 in the radial direction is fixed to the motor housing 10. The stator 21 is made of, for example, an annular ferromagnetic laminated steel plate, and a plurality of slots (not shown) around which the coil 22 is wound are formed in the inner peripheral portion of the stator 21.

The rotor 30 is arranged inside the stator 21 in the radial direction. The rotor 30 includes a rotor core 32 and a rotor shaft 34 that defines the rotating shaft 12 of the traveling motor 40. The rotor core 32 is fixed to the outside in the radial direction of the rotor shaft 34, and rotates integrally with the rotor shaft 34. The rotor shaft 34 is rotatably supported by the motor housing 10 via bearings 14a and 14b. In the example shown in FIG. 2, the bearings 14a and 14b can be of an open type using lubricating oil due to the lubrication structure described later. However, in the modified example, at least one of the bearings 14a and 14b may be a grease-filled type. The bearing 14a is provided between the end portion of the rotor shaft 34 on the X1 side and the inner diameter side housing 10b in the radial direction. The bearing 14b is provided in the radial direction between the end of the rotor shaft 34 on the X2 side and the annular protrusion 11d of the cover housing 10c.

The rotor core 32 is made of, for example, an annular ferromagnetic laminated steel plate. A permanent magnet 321 may be embedded inside the rotor core 32. Alternatively, the permanent magnet 321 may be embedded in the outer peripheral surface of the rotor core 32. When the permanent magnets 321 are provided, the arrangement of the permanent magnets 321 and the like is arbitrary.

End plates 35A and 35B are attached to both sides of the rotor core 32 in the axial direction. The end plates 35A and 35B may have a function of preventing the permanent magnet 321 from popping out and the like, and a function of adjusting the imbalance of the rotor 30 (a function of eliminating the imbalance by cutting or the like).

The rotor shaft 34 has a hollow portion 34A. The hollow portion 34A is closed on one end side (X1 side) in the axial direction and opens on the other end side (X2 side) in the axial direction, and extends over the entire length of the rotor shaft 34 in the axial direction.

The rotor shaft 34 is connected to the power transmission mechanism 7 on one end side (X1 side) in the axial direction. FIG. 2 shows only a part of the power transmission mechanism 7. The power transmission mechanism 7 is connected to the output shaft (not shown) of the vehicle, and transmits the rotational torque generated in the rotor shaft 34 of the traveling motor 40 to the output shaft of the vehicle. The configuration of the power transmission mechanism 7 is arbitrary, and may include a transmission, a reduction mechanism, and the like.

Next, the flow of oil and cooling water in the traveling motor 40 shown in FIG. 2 will be described.

The cooling water flows axially from the X1 side through the water channel 901 (see arrow R1), flows inward in the radial direction through the water channel 903 through the water channel 902 (see arrow R2), and then passes through the water channel 904 to X1. It flows in the axial direction toward the side (see arrow R3). Then, it flows into the hollow portion 34A of the rotor shaft 34 (see arrow R4). When the cooling water flows into the hollow portion 34A while the hollow portion 34A of the rotor shaft 34 is filled with cooling water (see arrow R4), a part of the cooling water in the hollow portion 34A of the rotor shaft 34 becomes. It flows out of the hollow portion 34A of the rotor shaft 34 through the water channel 905 (see arrow R5) and is returned through the water channel 906 (see arrow R6). The cooling water returned through the water channel 906 is cooled via, for example, a radiator or the like, and is discharged to the water channel 901 again by a water pump (not shown).

When the cooling water is circulated in this way, the oil in the oil passage 801 can be cooled when passing through the water channel 901, and the stator 21 can be cooled through the oil. Further, new cooling water (cooling water from the oil pump) can be continuously supplied to the hollow portion 34A of the rotor shaft 34 by replacing the cooling water in the hollow portion 34A with new cooling water, and the rotor core 32 has a diameter. Can be cooled from the inside in the direction. Thereby, the magnet cooling performance can be effectively improved. In particular, in the example shown in FIG. 2, since the hollow portion 34A of the rotor shaft 34 has a relatively large inner diameter r1, weight reduction is achieved, and the inner peripheral surface of the hollow portion 34A of the rotor shaft 34 and the permanent magnet 321 The radial distance between them can be shortened (for example, it can be shortened as compared with the case where the inner diameter r1 ≈ outer diameter r2), and the magnet cooling performance can be effectively improved.

The oil flows circumferentially through the oil passage 801 (arrows are not shown) and cools the stator 21. In the modified example, cooling through the oil passage 801 may be omitted.

Further, in the example shown in FIG. 2, the oil is supplied to the bearing arrangement space 92 via the oil passage 810 and is used for lubricating the bearing 14b (see arrows R20 and R21). Therefore, in the example shown in FIG. 2, the bearing 14b does not need to be a grease-filled type, and inconvenience when it is a grease-filled type can be prevented. That is, when the bearing 14b is a grease-filled type, there is a tendency to provide a clearance in the radial inner seal portion to prevent friction in response to the increase in rotation speed of the traveling motor 40. Then, grease may flow out to the clearance at high temperature. In the example shown in FIG. 2, such an inconvenience can be prevented by using an open type bearing 14b that is not a grease-filled type.

In this way, in the example shown in FIG. 2, oil can be supplied to the bearing 14b while it is possible to supply cooling water to the hollow portion 34A of the rotor shaft 34 to efficiently cool the rotor core 32.

By the way, as in the example shown in FIG. 2, when supplying cooling water to the hollow portion 34A of the rotor shaft 34, it is useful to improve the sealing property between the hollow portion 34A of the rotor shaft 34 and the bearing arrangement space 92. is there. This is because if the cooling water flows into the bearing arrangement space 92, the function of the open type bearing 14b is affected.

In this regard, in the example shown in FIG. 2, the traveling motor 40 further includes two first seal members 60 and 61. The first seal members 60 and 61 are provided between the hollow portion 34A of the rotor shaft 34 and the bearing arrangement space 92. As a result, the sealing property between the hollow portion 34A of the rotor shaft 34 and the bearing arrangement space 92 can be improved.

Specifically, the first seal members 60 and 61 each have a ring shape when viewed in the axial direction, and the outer side in the radial direction abuts on the inner peripheral surface of the hollow portion 34A of the rotor shaft 34 and the inner side in the radial direction. Is supported by the shaft-shaped portion 11c. The first seal members 60 and 61 are provided in such a manner that both ends of the shaft annular space 90 in the axial direction are bound to each other.

The first seal members 60 and 61 are provided at different positions in the axial direction. Specifically, the first seal member 60 is provided at the axial X1 side end portion of the axial portion 11c, and the first seal member 61 is the axial X2 side end portion of the hollow portion 34A of the rotor shaft 34. It is provided in. In other words, the first sealing member 60 seals the X1 side of the shaft annular space 90 in the axial direction, and the first sealing member 61 seals the X2 side of the shaft annular space 90 in the axial direction.

The first seal member 60 functions to prevent cooling water from flowing into the shaft annular space 90 from the hollow portion 34A of the rotor shaft 34. Further, the first seal member 61 functions to prevent oil from flowing into the shaft annular space 90 from the bearing arrangement space 92.

In this way, according to the example shown in FIG. 2, the shaft annular shape is sealed on both sides in the axial direction by the first sealing members 60 and 61 between the hollow portion 34A of the rotor shaft 34 and the bearing arrangement space 92. Space 90 is formed. That is, a space (dry space) in which neither cooling water nor oil exists is formed between the hollow portion 34A of the rotor shaft 34 and the bearing arrangement space 92. As a result, the sealing property can be improved as compared with the case where only one of the first sealing members 60 and 61 is provided between the hollow portion 34A of the rotor shaft 34 and the bearing arrangement space 92.

Further, in the example shown in FIG. 2, the space 94 in which the coil ends 22A and 22B (the axial ends of the coil 22 of the traveling motor 40) are located is a dry space (a space in which oil is not introduced). Will be done. Therefore, in the example shown in FIG. 2, a second seal member 62 is provided between the space 94 and the bearing arrangement space 92. The second seal member 62 functions to prevent oil from flowing into the space 94 from the bearing arrangement space 92. In the example shown in FIG. 2, the second seal member 62 is provided between the rotor shaft 34 and the annular protrusion 11d in the radial direction. The second seal member 62 is provided in a manner adjacent to the bearing 14b from the X1 side in the axial direction. The second seal member 62 is provided on the X2 side in the axial direction of the communication passage 700 so that oil does not enter the shaft annular space 90 through the communication passage 700.
Further, in this embodiment, a seal member 64 is provided between the space 94 and the bearing 14a. The seal member 64 functions to prevent oil from flowing into the space 94 from the space 98 in which the bearing 14a is located. In this case, the bearing 14a can be oil-lubricated in the space 98, and the bearing 14a can be an open type like the bearing 14b.

By the way, in the example shown in FIG. 2, the space 94 in which the coil ends 22A and 22B are located is regarded as a dry space (a space in which oil is not introduced) and is directly cooled by oil (for example, the coil ends 22A and 22B). Cooling by dripping oil on the air) is not realized.

In this regard, in this embodiment, as shown in FIG. 2, the coil ends 22A and 22B are provided with the thermoelectric element 4. The thermoelectric element 4 is an element capable of converting thermal energy into electrical energy. Specifically, as shown in FIG. 2, the thermoelectric element 4 includes a thermoelectric element 4A provided at the coil end 22A and a thermoelectric element 4B provided at the coil end 22B. In this case, the thermal energy (copper loss) generated at the two coil ends 22A and 22B can be effectively used, and as a result, the efficiency of the motor drive system 1 can be improved. However, in the modified example, one of the thermoelectric elements 4A and 4B may be omitted.

The thermoelectric element 4A may be provided over the entire circumference of the coil end 22A, or may be provided only on a part of the entire circumference of the coil end 22A. Further, the thermoelectric element 4A may be directly connected to the coil end 22A, or may be connected to the coil end 22A via a heat transfer body such as a thermal sheet. The same applies to the thermoelectric element 4B.

In the example shown in FIG. 2, the thermoelectric element 4A is thermally connected to the coil end 22A on the inner side in the radial direction and to the housing 10b on the inner diameter side in the radial direction.

Here, as described above, the inner diameter side housing 10b is provided adjacent to the water channel 901, so that the temperature is relatively low. Therefore, the thermoelectric element 4A is thermally connected to the coil end 22A having a relatively high temperature on the inner side in the radial direction, and is thermally connected to the inner diameter side housing 10b having a relatively low temperature on the outer side in the radial direction. The thermoelectric element 4A can convert thermal energy into electrical energy by utilizing such a thermal gradient. The same applies to the thermoelectric element 4B. In the case of the type of thermoelectric element 4 that does not utilize the thermal gradient, the thermoelectric element 4 may be thermally connected to the coil ends 22A and 22B.

Although the traveling motor 40 having a specific structure is shown in FIG. 2, the structure of the traveling motor 40 is arbitrary as long as the thermoelectric element 4 is provided at the coil ends 22A and 22B. Therefore, for example, the traveling motor 40 does not have to have a water channel 901, a hollow portion 34A, or the like. Further, although a specific cooling method and lubrication method are disclosed in FIG. 2, the cooling method and lubrication method of the traveling motor 40 are arbitrary. Therefore, for example, if the thermoelectric element 4 can function in the space where the oil is introduced, the space 94 does not have to be a dry space.

Further, in the example shown in FIG. 2, the thermoelectric element 4 is thermally connected to the coil ends 22A and 22B, but instead of or in addition to this, it may be thermally connected to another heat generating portion. In this case, the other heat generating portion is arbitrary as long as it is a heat generating portion that generates heat when the traveling motor 40 is driven. For example, the other heat generating portion may be another component of the traveling motor 40, or may be a component of a power conversion device including the inverter 6 and the inverter control device 50. For example, the other heat generating portion is a heat spreader (FIG.) thermally connected to a bus bar (not shown) used in the traveling motor 40 or the inverter 6 or a heat generating element (for example, switching elements Q1 to Q6) of the inverter 6. (Not shown) or the like.

Next, with reference to FIG. 3, an example of the usage mode of the electric energy generated by the thermoelectric element 4 will be described.

Here, as a usage mode of the electric energy generated by the thermoelectric element 4, the usage mode in the inverter control device 50 will be described.

FIG. 3 is a schematic view showing an example of a power supply configuration according to the inverter control device 50. FIG. 3 schematically shows a configuration mounted on the substrate S. In FIG. 3, + B represents the power supply from the low voltage battery (eg, lead battery) 3 of 12V, and GND represents the ground potential. Further, the IGSW represents an ignition power supply that functions when the ignition switch is in the ON state. The meanings of P and N are as described above.

In FIG. 3, the line L is a line that separates the low voltage system and the high voltage system, the P terminal 180 side of the line L is the “high voltage system (high voltage)”, and the opposite side is the “low voltage system (low voltage)”. is there. That is, the substrate S is divided into a low-voltage system region S1 and a high-voltage system region S2 via an insulating region (not shown). The insulating region is a region that does not include any conductor including the inner layer of the substrate S, extends between the low-voltage system region S1 and the high-voltage system region S2, and has a function of electrically insulating both. In the low-voltage system region S1, for example, an interface 194 (denoted as "CAN communication I / F" in FIG. 3) for CAN (controller area network) communication and the like are mounted.

The inverter control device 50 includes a microcomputer 51 (denoted as “microcomputer” in FIG. 3). The microcomputer 51 includes, for example, a CPU, a ROM, a main memory (all not shown), and the like. Various functions of the inverter control device 50 are realized by reading the control program recorded in the ROM or the like into the main memory and executing it by the CPU. The control method of the inverter 6 is arbitrary, but basically, the two switching elements Q1 and Q2 related to the U phase are turned on / off in opposite phases, and the two switching elements Q3 and Q4 related to the V phase are turned on and off. The two switching elements Q5 and Q6 related to the W phase are turned on / off in opposite phases to each other.

In the high-voltage system region S2 of the substrate S, the high-voltage side voltage detection unit 187, the MOSFET drive unit 520 (denoted as "MOSFET drive IC" in FIG. 3), the temperature detection unit 530, the three-phase current detection unit 540, and the resolver interface 550 ( In FIG. 3, it is described as "resolver I / F"), and a motor coil temperature detection unit 560 is provided. The high-voltage side voltage detection unit 187, MOSFET drive unit 520, temperature detection unit 530, three-phase current detection unit 540, resolver interface 550, and motor coil temperature detection unit 560 are connected to the microcomputer 51.

The high-voltage side voltage detection unit 187 detects the voltage of the P terminal 180 and gives the detected value to the microcomputer 51 or the like.

The MOSFET drive unit 520 is a drive IC (Integrated Circuit) that drives the switching elements Q1 to Q6, which are MOSFETs, and applies a drive signal to the gate of the switching elements Q1 to Q6 in response to a command from the microcomputer 51. The MOSFET drive unit 520 is connected to both the upper drive power source 70 and the lower drive power source 72, as schematically shown in FIG. Specifically, among the MOSFET drive units 520, the drive unit that drives the upper switching elements Q1, Q3, and Q5 is connected to the upper drive power supply 70 and drives the lower switching elements Q2, Q4, and Q6. The unit is connected to the lower drive power supply 72.

The temperature detection unit 530 detects the temperature of the switching elements Q1 to Q6 based on the resistance value of the thermistor 48 provided corresponding to each of the switching elements Q1 to Q6.

The three-phase current detection unit 540 detects the current flowing through each phase of the traveling motor 40 based on the output from the three-phase current sensor 42 provided in each phase of the traveling motor 40.

The resolver interface 550 is an interface between the resolver 44 and the microcomputer 51. The microcomputer 51 detects the rotation angle of the traveling motor 40 based on the output from the resolver 44.

The motor coil temperature detection unit 560 detects the temperature of the coil of the traveling motor 40 based on the resistance value of the thermistor 46 provided in the traveling motor 40. The thermistor 46 may be provided at the coil ends 22A and 22B.

As a power supply system, the inverter control device 50 includes an upper drive power supply 70 for driving the upper switching elements Q1, Q3, and Q5, a lower drive power supply 72 for driving the lower switching elements Q2, Q4, and Q6. It includes a microcomputer power supply 74 for the microcomputer 51, a step-down power supply 75, and an isolated power supply 76.

The upper drive power supply 70 is connected to the P terminal 180 connected to the positive electrode side of the smoothing capacitor 5. The upper drive power supply 70 is connected to the P terminal 180 via the line 182 and is connected to the P terminal 180 via the line 184. The line 184 is provided with a step-down power supply 75 including a step-down circuit. The step-down power source 75 steps down 48V to 21V as described later. Therefore, the upper drive power supply 70 is supplied with a voltage of 48 V via the line 182 and a voltage of 21 V via the line 184.

Further, the upper drive power supply 70 is connected to the + B terminal 188 via the line 186 connected to the line 184 at the connection point P1. The line 186 is provided with an insulated power supply 76. Therefore, the upper drive power supply 70 can be supplied with a voltage lower than 48 V by two systems, a system via the step-down power supply 75 and a system via the isolated power supply 76.

The upper drive power supply 70 generates a power supply voltage necessary for driving the upper switching elements Q1, Q3, and Q5 based on the voltage supplied as described above. Specifically, the upper drive power supply 70 includes a booster circuit 70a. The booster circuit 70a is, for example, a charge pump (CP) circuit, and may function so that the output voltage becomes 48 V. Alternatively, the booster circuit 70a may be a circuit that boosts the output voltage to a voltage higher than 48V. Further, the upper drive power supply 70 may include a constant voltage circuit (for example, an LDO (Low Drop Out) linear regulator) in addition to the booster circuit 70a.

The lower drive power supply 72 is connected to the P terminal 180 via the line 184 and is connected to the + B terminal 188 via the line 186. Therefore, the lower drive power supply 72 can be supplied with a voltage lower than 48 V by two systems, a system via the step-down power supply 75 and a system via the isolated power supply 76.

The lower drive power supply 72 generates the power supply voltage required to drive the lower switching elements Q2, Q4, and Q6 based on the voltage supplied as described above. The lower drive power supply 72 may include a constant voltage circuit (eg, an LDO linear regulator).

The microcomputer power supply 74 is connected to the P terminal 180 via the line 184 and is connected to the + B terminal 188 via the line 186. Therefore, a voltage lower than 48V is supplied to the microcomputer power supply 74 by two systems, a system via a step-down power supply 75 and a system via an isolated power supply 76. The microcomputer power supply 74 generates a power supply (for example, a power supply voltage of 5 V) for operating the microcomputer 51 based on the voltage supplied as described above.

The step-down power supply 75 steps down the high voltage (48V) obtained based on the P terminal 180 to 21V. Note that 21V is just an example, and may be another voltage less than 48V and larger than 12V. The step-down power supply 75 is connected to the connection point P1 via the diode D1.

The insulated power supply 76 is connected to the + B terminal 188 via the line 192 and is connected to the terminal 189 via the line 190. The insulated power supply 76 insulates the low voltage system from the high voltage system in order to supply the power from the + B terminal 188 or the terminal 189 to the high voltage system. In the insulated power supply 76, the high voltage side and the low voltage side are insulated via, for example, a transformer. The insulated power supply 76 is connected to the connection point P1 via the diode D2. The output voltage of the isolated power supply 76 is, for example, 12V, which is lower than the output voltage of the step-down power supply 75 of 21V. Therefore, when the output voltage of the step-down power supply 75 is 21V, which is a normal value, a voltage caused by the step-down power supply 75 is generated at the connection point P1. On the other hand, if the output voltage of the step-down power supply 75 drops to less than 12V when the high-voltage power supply fails, which will be described later, a voltage of 12V due to the insulated power supply 76 is generated at the connection point P1.

In particular, in this embodiment, the insulated power supply 76 is connected to the terminal 189 via the line 190 as described above. The line 190 is provided with a diode D3 that allows only current in the direction toward the insulated power source 76, and is connected to the other end of the capacitor C3 whose one end is grounded. Therefore, in this embodiment, the insulated power supply 76 can generate a power supply voltage of 12 V based on the power from the terminal 189.

Specifically, when the coil ends 22A and 22B generate heat as the traveling motor 40 is driven, the thermoelectric element 4 converts the thermal energy of the coil ends 22A and 22B into electric energy. As a result, electric charges are accumulated in the capacitor C3, and a power supply voltage of 12 V is generated by the insulating power supply 76 based on the electric charges. For example, the insulated power supply 76 may generate a power supply voltage of 12 V by utilizing the electric charge of the capacitor C3 when the voltage across the capacitor C3 becomes higher than the voltage appearing at the + B terminal 188. Alternatively, the insulated power supply 76 may include a switch circuit inside, and when a predetermined condition is satisfied, the power supply voltage of 12 V may be generated based on the charge of the capacitor C3 by switching the state of the switch circuit. In this case, the predetermined conditions are arbitrary, but may be satisfied, for example, when the temperature detected by the thermistor 46 exceeds the predetermined temperature.

In the example shown in FIG. 3, the microcomputer 51 is mounted in the high-voltage system region of the substrate S, as schematically shown in FIG. Further, when the power supply system is normal, a voltage caused by the step-down power supply 75 is generated at the connection point P1 (because the output voltage of the step-down power supply 75> the output voltage of the isolated power supply 76). Therefore, the microcomputer 51 is based on the high-voltage power supply (power supply caused by the high-voltage battery 2) obtained via the P terminal 180 in a normal state (a state in which the power supply system is not collapsed as described later). Can work.

FIG. 4 is a display diagram showing a power supply mode (fail-safe mode) at the time of fail in the power supply configuration shown in FIG.

A low-voltage power supply failure is a state in which the insulated power supply 76 cannot generate a power supply voltage of 12V. The low voltage system power failure is typically caused by an abnormality relating to the low voltage battery 3. The abnormality related to the low-voltage battery 3 is caused by an abnormality of the low-voltage battery 3 itself, wiring, or the like, and causes a state in which the voltage at the + B terminal 188 is significantly lower than the normal value.

When the low voltage system power failure occurs, the upper drive power source 70 cannot generate a power source based on the insulated power source 76 via the line 186, but is based on the P terminal 180 via the line 182 and the line 184. It is still possible to generate power. Therefore, even if the low-voltage power supply fails, it is still possible to drive the upper switching elements Q1, Q3, and Q5 via the upper drive power supply 70.

Further, when the low voltage system power supply fails, the lower stage drive power supply 72 cannot generate a power supply based on the insulated power supply 76 via the line 186, but is based on the P terminal 180 via the line 184. It is still possible to generate power. Therefore, even if the low-voltage power supply fails, the lower switching elements Q2, Q4, and Q6 can still be driven via the lower drive power supply 72.

Further, when the low-voltage system power supply fails, the microcomputer power supply 74 cannot generate a power supply based on the insulated power supply 76 via the line 186, but the power supply is based on the P terminal 180 via the line 184. Is still possible to generate. Therefore, even if the low-voltage system power supply fails, the microcomputer 51 can still operate via the microcomputer power supply 74.

As described above, in the example shown in FIG. 3, when the power supply system is normal, the upper drive power supply 70, the lower drive power supply 72, and the microcomputer power supply 74 all operate based on the power from the high voltage battery 2. The functions of the upper drive power supply 70, the lower drive power supply 72, and the microcomputer power supply 74 themselves are not affected even if the low voltage system power supply fails.

The high-voltage power supply failure is caused by an abnormality related to the high-voltage battery 2, specifically, an abnormality of the high-voltage battery 2 itself, an open failure of the cutoff switch SW1, or the like, and the voltage at the P terminal 180 is increased. It produces a condition that is significantly lower than the normal value.

When the high-voltage power supply fails, the upper drive power supply 70 cannot generate a power supply based on the P terminal 180 via the line 182, but the power supply is supplied based on the insulated power supply 76 via the line 186. It is possible to generate. At this time, the booster circuit 70a functions. Therefore, even if the high-voltage power supply fails, it is still possible to drive the upper switching elements Q1, Q3, and Q5 via the upper drive power supply 70.

Further, when the high-voltage power supply fails, the lower drive power supply 72 cannot generate a power supply based on the P terminal 180 via the line 184, but is based on the insulated power supply 76 via the line 186. It is possible to generate a power source. Therefore, even if the high-voltage power supply fails, it is still possible to drive the lower switching elements Q2, Q4, and Q6 via the lower drive power supply 72.

Further, when the high voltage system power supply fails, the microcomputer power supply 74 cannot generate a power supply based on the P terminal 180 via the line 184, but the power supply is based on the insulated power supply 76 via the line 186. It is possible to generate. Therefore, even if the high-voltage power supply fails, the microcomputer 51 can still operate via the microcomputer power supply 74.

In this way, according to the example shown in FIG. 3, the microcomputer 51 can operate regardless of whether the low-voltage system power supply failure or the high-voltage system power supply failure occurs. Further, regardless of whether the low voltage system power supply fails or the high voltage system power supply fails, the upper drive power supply 70 and the lower drive power supply 72 can function as described above, so that the low voltage system power supply failure and the high voltage system power supply failure occur. Whichever of the above occurs, the microcomputer 51 can make the inverter 6 function.

Here, in the present embodiment, as described above, since the thermoelectric element 4 is connected to the insulated power supply 76, even if an abnormality related to the low voltage battery 3 occurs, the low voltage system power supply may fail. Can be reduced. This is because, as described above, when the calorific value of the coil ends 22A and 22B is relatively high, the insulated power supply 76 can maintain a state of generating a power supply voltage of 12 V based on the electric energy from the thermoelectric element 4. Is.

In this way, in the example shown in FIG. 3, the possibility that the low-voltage system power supply fails can be reduced based on the electric energy generated by the thermoelectric element 4. Further, in the example shown in FIG. 3, even when the low-voltage system power failure finally occurs due to the lack of electric energy generated by the thermoelectric element 4, or when the high-voltage system power failure occurs. The high-voltage side voltage detection unit 187, the MOSFET drive unit 520, the temperature detection unit 530, the three-phase current detection unit 540, the resolver interface 550, and the motor coil temperature detection unit 560 can operate. That is, the high voltage side voltage detection unit 187, the MOSFET drive unit 520, the temperature detection unit 530, the three-phase current detection unit 540, the resolver interface 550, and the motor coil temperature detection unit 560 have a + B terminal when a high voltage system power failure occurs. It can operate based on the power source generated via the 188 (or terminal 189), and when a low voltage system power failure occurs, it can operate based on the power source generated via the P terminal 180.

Therefore, the microcomputer 51 uses the temperature detection unit 530, the three-phase current detection unit 540, the resolver interface 550, and the motor coil temperature detection unit 560 regardless of whether the low-voltage system power supply failure or the high-voltage system power supply failure occurs. The inverter 6 can be controlled based on the information obtained through the system.

Although a specific power supply configuration is shown in FIG. 3 (and FIG. 4), the power supply configuration according to the inverter control device 50 may be arbitrary as long as the electric energy from the thermoelectric element 4 is used. For example, in FIG. 3, the microcomputer 51 is provided in the high-voltage system region S2, but may be provided in the low-voltage system region S1. In this case, the microcomputer power supply 74 may also be provided in the low voltage system region S1, and the electric energy from the thermoelectric element 4 may be used in the microcomputer power supply 74 or in the lower drive power supply 72.

Further, in the example shown in FIG. 3, the isolated power supply 76 has a power supply voltage (second power supply voltage) of 12 V based on the power (electrical energy) input from the low voltage battery 3 (an example of an in-vehicle battery) via the + B terminal 188. A 12V power supply voltage (first power supply) based on a circuit that generates (an example) (an example of a second power supply circuit) and power (electrical energy) input from terminal 189 (that is, thermoelectric element 4) via terminal 189. It includes a circuit (an example of a first power supply circuit) that generates a voltage (an example of a voltage) integrally, but these circuits may be mounted separately. In this case, the circuit of the insulated power supply 76 that generates a power supply voltage of 12 V based on the power from the terminal 189 (that is, the thermoelectric element 4) may include a constant voltage circuit (for example, an LDO linear regulator). ..

Further, in the example shown in FIG. 3, one end of the line 190 is connected to the terminal 189 and the other end is connected to the insulated power supply 76, while the other end is the line 192 between the + B terminal 188 and the insulated power supply 76. It may be connected to the line 191 between the ignition power supply and the insulated power supply 76.

Further, in the example shown in FIG. 3, the electric energy from the thermoelectric element 4 is used in the low voltage system, but may be used in the high voltage system. For example, one end of the line 190 may be connected to the terminal 189, and the other end may be connected to the line 182, the upper drive power supply 70, or the like.

Although each embodiment has been described in detail above, the present invention is not limited to a specific embodiment, and various modifications and changes can be made within the scope of the claims. It is also possible to combine all or a plurality of the components of the above-described embodiment.

<Additional notes>
The following will be further disclosed with respect to the above examples. Of the effects described below, the effect relating to each additional form with respect to one form is an additional effect resulting from each of the additional forms.

(1) One form is a rotary electric machine (40) and
A thermoelectric element (4) that is thermally connected to heat generating portions (22A, 22B) that generate heat when the rotary electric machine is driven and can convert thermal energy into electric energy.
Includes a first power supply circuit (76) that is electrically connected to the thermoelectric element and generates a first power supply voltage based on the electrical energy from the thermoelectric element.
The rotary electric machine is a vehicle drive device that can operate based on the first power supply voltage generated by the first power supply circuit.

According to this embodiment, the rotary electric machine can operate based on the first power supply voltage generated by the first power supply circuit, and the first power supply voltage is generated based on the electric energy from the thermoelectric element, and the thermoelectric element. Is thermally connected to a heat generating portion that generates heat when the rotary electric machine is driven. Therefore, according to this embodiment, the heat energy generated by the heat generating portion that generates heat when the rotary electric machine is driven can be effectively used.

(2) Further, in the present embodiment, preferably, the power conversion device (6) electrically connected to the rotary electric machine and
Further including a control device (50) for controlling the power conversion device.
The power conversion device or the control device can operate based on the first power supply voltage generated by the first power supply circuit.

In this case, the power conversion device or the control device operates based on the first power supply voltage, so that the rotary electric machine can operate based on the first power supply voltage.

(3) Further, in the present embodiment, preferably, the power conversion device (6) electrically connected to the rotary electric machine and
A control device (50) that controls the power conversion device and
It further includes a second power supply circuit (76) that is electrically connected to the vehicle-mounted battery (3) and generates a second power supply voltage based on the electrical energy from the vehicle-mounted battery.
The power conversion device or the control device can operate based on the first power supply voltage generated by the first power supply circuit and the second power supply voltage generated by the second power supply circuit.

In this case, the power conversion device or the control device operates based on the first power supply voltage, so that the rotary electric machine can operate based on the first power supply voltage. Further, since the rotary electric machine can operate based on the second power supply voltage, the redundancy for the fail can be increased.

(4) Further, in the present embodiment, preferably, the heat generating portion includes at least one component of the rotary electric machine and the power conversion device.

In this case, the rotary electric machine can be operated by utilizing the heat generated by at least one of the components of the rotary electric machine and the power conversion device.

(5) Further, in the present embodiment, preferably, the heat generating portion includes axial ends (22A, 22B) in the stator coil of the rotary electric machine.

In this case, the thermal energy related to the copper loss generated at the end of the stator coil (that is, the coil end) can be effectively used.

1 Motor drive system 2 High-voltage battery 3 Low-voltage battery 4 Thermoelectric element 5 Smoothing capacitor 6 Inverter 22 Coil 22A Coil end 22B Coil end 40 Traveling motor 42 Three-phase current sensor 44 Resolver 48 Thermista 50 Inverter controller 51 Microcomputer 70 Upper drive power supply 70a Booster circuit 72 Lower drive power supply 74 Microcomputer power supply 75 Step-down power supply 76 Insulated power supply 180 P terminal 182 Line 184 Line 186 Line 187 High voltage side voltage detection unit 188 + B terminal 189 terminal 190 Line 520 MOSFET drive unit 530 Temperature detection unit 540 Three-phase current Detector 550 Resolver interface 560 Motor coil temperature detector

Claims (5)

With a rotary electric machine
A thermoelectric element that is thermally connected to a heat generating part that generates heat when the rotary electric machine is driven and can convert thermal energy into electric energy.
Includes a first power supply circuit that is electrically connected to the thermoelectric element and generates a first power supply voltage based on the electrical energy from the thermoelectric element.
The rotary electric machine is a vehicle drive device that can operate based on the first power supply voltage generated by the first power supply circuit. A power converter electrically connected to the rotary electric machine and
Further including a control device for controlling the power conversion device,
The vehicle drive device according to claim 1, wherein the power conversion device or the control device can operate based on the first power supply voltage generated by the first power supply circuit. A power converter electrically connected to the rotary electric machine and
A control device that controls the power conversion device and
It further includes a second power supply circuit that is electrically connected to the vehicle-mounted battery and generates a second power supply voltage based on the electrical energy from the vehicle-mounted battery.
The power conversion device or the control device can operate based on the first power supply voltage generated by the first power supply circuit and the second power supply voltage generated by the second power supply circuit. Item 2. The vehicle drive device according to item 1. The vehicle drive device according to claim 2 or 3, wherein the heat generating unit includes at least one component of the rotary electric machine and the power conversion device. The vehicle drive device according to claim 4, wherein the heat generating portion includes an axial end portion of the stator coil of the rotary electric machine.