Cooling device for inverter

Abstract

To efficiently cool an inverter.SOLUTION: An electric vehicle comprises a motor M for driving, a generator 5, an inverter 10 including a plurality of power modules, and an inverter cooling device 20 which cools the inverter 10. The inverter cooling device 20 includes: a coolant passage 22 in which a coolant flows; a pump 21 which supplies the coolant to the coolant passage 22; and a valve device 23 which is disposed in the coolant passage 22. The coolant passage 22 in a casing 14 in which the plurality of power modules is stored passes a first point X and a second point Y. An inverter cooling control section 42 is included which switches a flow direction of the coolant in the coolant passage 22 between one direction from the first point X to the second point Y and the other reverse direction by controlling the valve device 23.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cooling device for an inverter used in an electric vehicle. [Background technology]

[0002] In electric vehicles equipped with a motor as a driving source, the motor is driven by electricity stored in a battery or electricity generated while the vehicle is traveling. The motor also functions as a generator to generate regenerative power, mainly during coasting. This motor is controlled through an inverter.

[0003] Inverters mounted on electric vehicles are cooled by a refrigerant such as water, as shown in Patent Document 1. In particular, it is important to keep the inverter within an appropriate temperature range because the power module (power semiconductor) mounted on the inverter plays a role in passing current, i.e., outputting torque, within a range that does not exceed a predetermined upper limit temperature. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-88180 Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, inverters for electric vehicles (EVs) that do not have an engine as a driving source are composed of an MCU (Motor Control Unit) for driving the motor. In addition, in hybrid vehicles (HVs / PHEVs) that have an engine and a motor as a driving source, a GCU (Generator Control Unit) for driving the generator is installed alongside the MCU for driving the motor as a power module located within the inverter, and if a voltage step-up mechanism is included, a VCU (Voltage Control Unit) is also installed.

[0006] Temperature differences can occur at different locations within the inverter installed in a hybrid vehicle (HV / PHEV). This is due in part to the fact that the heat generation amounts of the VCU, MCU, and GCU differ depending on the driving state, and also because the coolant used to cool the inverter gradually increases in temperature as it moves from the upstream to the downstream side within the inverter. Another factor that contributes to the large temperature differences is that the VCU, MCU, and GCU are all constantly cooled, regardless of the driving mode or whether the generator is running. In order for the inverter to perform as expected, it is desirable for the inverter to be cooled efficiently at all times.

[0007] Therefore, an object of the present invention is to efficiently cool the inverter. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention employs an electric vehicle including a drive motor and generator, an inverter including a plurality of power modules, and an inverter cooling device that cools the inverter, the inverter cooling device including a refrigerant passage through which a refrigerant flows, a pump that supplies refrigerant to the refrigerant passage, and a valve device that is provided in the refrigerant passage, the refrigerant passage in a casing that houses the plurality of power modules passes through a first point and a second point, and an inverter cooling control unit that controls the valve device to switch the flow direction of the refrigerant in the refrigerant passage between one direction from the first point to the second point and another direction opposite thereto (Configuration 1).

[0009] In configuration 1, a first temperature sensor is provided at the first point and a second temperature sensor is provided at the second point, and the inverter cooling control unit can adopt a configuration in which the flow direction of the refrigerant is switched between the one direction and the other direction based on the temperature difference between the first temperature sensor and the second temperature sensor (configuration 2).

[0010] In configuration 1 or 2, the first point and the second point are openings of the casing, and a first refrigerant passage and a second refrigerant passage are provided outside the casing, and the inverter cooling control unit controls the valve device to open the refrigerant passage from the pump to the refrigerant passage in the casing at the first point, and to open the refrigerant passage returning to the pump to the refrigerant passage in the casing at the second point, thereby changing the flow direction of the refrigerant to the one direction, to open the refrigerant passage from the pump to the first refrigerant passage and to open the refrigerant passage in the casing to the second refrigerant passage at the first point, and to open the refrigerant passage returning to the pump to the second refrigerant passage and to open the first refrigerant passage to the refrigerant passage in the casing at the second point, thereby changing the flow direction of the refrigerant to the other direction (configuration 3).

[0011] In configuration 3, when switching the refrigerant flow between the one direction and the other direction, the inverter cooling control unit can adopt a configuration in which all of the valve devices are once opened and then the valve devices are opened to a predetermined state corresponding to the switching (configuration 4).

[0012] In any one of configurations 1 to 4, the power module includes a voltage control unit that controls the voltage supplied to the drive motor, a motor control unit that controls the rotation of the drive motor, and a generator control unit that controls the power generation by the generator, and the first point and the second point are set in a main casing that houses the voltage control unit and the motor control unit, and a sub-casing that houses the generator control unit is provided downstream of the main casing in the flow of the refrigerant (configuration 5).

[0013] In any one of configurations 1 to 5, an engine is provided as a driving source for traveling, and the refrigerant passage in the sub-casing passes through a third point and a fourth point, the third point is connected to the upstream refrigerant passage, and the fourth point is connected to the refrigerant passage returning to the pump, and when the traveling mode is a parallel traveling mode in which traveling is performed using driving force from the driving motor and the engine or a series traveling mode in which the driving motor is driven by electric power generated by the generator, the upstream refrigerant passage is opened to a flow path in the sub-casing on the third point side, and the flow path in the sub-casing is opened to the refrigerant passage returning to the pump on the fourth point side, and when the traveling mode is an EV traveling mode in which traveling is performed using driving force from only the driving motor, a configuration can be adopted in which the upstream refrigerant passage and the flow path in the sub-casing are blocked on the third point side (configuration 6).

[0014] In any one of configurations 1 to 6, when the power switch of the vehicle is turned off, the inverter cooling control unit can be configured to open the refrigerant passage from the pump to the refrigerant passage in the casing at the first point side, and open the refrigerant passage returning to the pump to the refrigerant passage in the casing at the second point side (configuration 7). [Effects of the Invention]

[0015] According to the present invention, the inverter can be cooled efficiently. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is an overall view schematically illustrating a vehicle equipped with an inverter and a cooling device therefor according to an embodiment of the present invention; [Figure 2] FIG. 1 is a schematic diagram illustrating a cooling device for an inverter according to an embodiment. [Figure 3] FIG. 10 is a schematic diagram illustrating the case where refrigerant is supplied in the forward direction. [Figure 4] FIG. 10 is a schematic diagram illustrating a case where a refrigerant is supplied in the reverse direction. [Figure 5] FIG. 10 is a schematic diagram illustrating switching between the forward direction and the reverse direction. [Figure 6] 10 is a diagram showing the control of a cooling device. DETAILED DESCRIPTION OF THE INVENTION

[0017] An embodiment of the present invention will be described with reference to the drawings. This embodiment is a hybrid vehicle 1 (hereinafter referred to as vehicle 1) equipped with an inverter 10 that controls a drive motor M as a drive source for traveling, and an inverter cooling device 20 that cools the inverter 10.

[0018] As shown in Fig. 1, a vehicle 1 is equipped with a drive motor M (hereinafter referred to as motor M) and an engine 4 as drive sources for traveling, and the front wheels 2 are driven by the motor M and the engine 4. In the embodiment, the front motor 31 is controlled by a single inverter 10, but a rear motor may also be controlled by a single inverter 10 instead of the front motor 31. Also, a rear motor may be provided separately from the front motor 31 and controlled by the same inverter 10, or a rear inverter different from the inverter 10 may be provided and each motor may be controlled by its own inverter.

[0019] The vehicle 1 also includes a battery (secondary battery) 30 that supplies power to the front motor 31, an accelerator sensor 6 that detects the amount of depression of the accelerator pedal by the driver, a steering sensor 7 that detects the amount of steering, a vehicle speed sensor that detects the speed of the vehicle 1, and various other sensors that acquire information necessary for the running of the vehicle 1. A generator 5 that generates electricity using the driving force of the engine 4 is provided adjacent to the engine 4. The electricity generated by the generator 5 is charged into the battery 30.

[0020] The front motor 31 is connected to the drive shaft of the front wheels 2 via a transmission 33. The output of the front motor 31 is controlled by an inverter 10, which converts between direct current and alternating current. The inverter 10 also has a boost mechanism that converts power from the battery 30 to a predetermined voltage required to drive the motor M. The drive torque of the front motor 31 is controlled by the inverter 10 via an electronic control unit 40 in response to input from the driver. The electronic control unit 40 also controls the gear shifting operation by the transmission 33 based on the vehicle speed, the amount of accelerator depression, etc. These controls are performed by a driving control unit 41 within the electronic control unit 40.

[0021] The vehicle 1 is set to three driving modes: an electric driving mode (hereinafter referred to as EV mode) in which the vehicle runs solely on the driving force of the motor M; a series driving mode in which the vehicle runs solely on the driving force of the motor M while generating electricity with the generator 5; and a parallel driving mode in which the engine 4 and the motor M are used as the driving source for running. The driving control unit 41 selects the optimal driving mode depending on the state and driving condition of the vehicle 1 at that time, the driver's requests, etc. The motor M, the engine 4, etc. are controlled depending on the selected driving mode.

[0022] As shown in FIG. 1, the inverter 10 includes, within a casing 14, power modules including a VCU 11 (Voltage Control Unit 11) for controlling the boosting by the boost mechanism, an MCU 12 (Motor Control Unit 12) for controlling the driving of the motor M, and a GCU 13 (Generator Control Unit 13) for controlling the driving of the generator 5.

[0023] The inverter cooling device 20 (hereinafter referred to as the cooling device 20) includes a refrigerant passage 22 connected to the casing 14, and a pump 21 that sends out refrigerant to the refrigerant passage 22. The refrigerant is supplied into the casing 14 by the action of the pump 21, which causes heat to be absorbed from the internal power module and releases the heat absorbed by the refrigerant to the outside. The heat is released to the outside by a heat release unit (not shown), such as a radiator, provided midway through the refrigerant passage 22. In the embodiment, water is used as the refrigerant, but various fluid refrigerants made of other liquids such as oil or gases may also be used.

[0024] The present invention is based on the principle of efficiently cooling the inverter 10 by making it possible to switch the flow direction of the refrigerant supplied by the cooling device 20 to cool the power module between one direction and the other.

[0025] A valve device 23 capable of adjusting the flow rate is disposed at an appropriate position in the refrigerant passage 22. This valve device 23 will be referred to hereinafter as the flow rate adjustment valve 23. By opening and closing the flow rate adjustment valve 23 or adjusting the opening degree, it is possible to switch the flow path to supply the refrigerant depending on the operating state (travel mode, etc.) of the vehicle 1 and the temperature condition of the inverter 10. These controls are performed by an inverter cooling control unit 42 in the electronic control unit 40.

[0026] Further, a heat dissipation unit (radiator) 24 that dissipates heat absorbed by the refrigerant to the outside is provided in the refrigerant passage 22. In this embodiment, the refrigerant passage 22 is also connected to a water jacket 25 provided in the motor M, and also cools the motor M.

[0027] In the embodiment, the casing 14 accommodating the VCU 11 and the MCU 12 and the casing 14 accommodating the GCU 13 are provided separately. The casing 14 accommodating the VCU 11 and the MCU 12 is referred to as the main casing 14a, and the casing 14 accommodating the GCU 13 is referred to as the sub-casing 14b. The vehicle 1 has a boost mechanism, and therefore the VCU 11 is used frequently. For this reason, the sub-casing 14b accommodating the GCU 13 is provided downstream in the refrigerant flow direction from the main casing 14a accommodating the VCU 11.

[0028] The main casing 14a and the sub-casing 14b each have two openings, which serve as an inlet and an outlet for the refrigerant. Each opening has a nipple, and a pipe for supplying the refrigerant is connected to each opening, forming a refrigerant passage 22.

[0029] The refrigerant passage 22m in the main casing 14a passes through one opening (first point X) and the other opening (second point Y). The line connecting the first point X and the second point Y is a line that diagonally connects the main casing 14a, which is rectangular in plan view. The refrigerant passage 22n in the sub-casing 14b passes through one opening (third point V) and the other opening (fourth point W). The line connecting the third point V and the fourth point W is also a line that diagonally connects the sub-casing 14b, which is rectangular in plan view.

[0030] 2, of the refrigerant passage 22, an upstream refrigerant passage 22a extending from the pump 21 communicates with a first point X in the main casing 14. A first refrigerant passage 22b branches off from the upstream refrigerant passage 22a before the upstream refrigerant passage 22a reaches the first point X, and then, after passing through a first valve device 23a, a second refrigerant passage 22c branches off from the upstream refrigerant passage 22a.

[0031] The first refrigerant passage 22b extends downstream from the branch point with the upstream refrigerant passage 22a toward a second point Y of the main casing 14. After passing through the third valve device 23c, the first refrigerant passage 22b branches into a third refrigerant passage 22d and a fourth refrigerant passage 22e before reaching the second point Y. The third refrigerant passage 22d communicates with the other opening (the second point Y). Therefore, the first refrigerant passage 22b connects the first point X and the second point Y via the upstream refrigerant passage 22a and the third refrigerant passage 22d.

[0032] The fourth refrigerant passage 22e passes through the second valve device 23b, merges with the end of the second refrigerant passage 22c, passes through the sixth valve device 23f, and then communicates with the downstream refrigerant passage 22h, which returns to the pump 21 via the water jacket 25 of the motor M and the heat dissipation section 24.

[0033] The second refrigerant passage 22c extends downstream from the branch point with the upstream refrigerant passage 22a toward a second point Y of the main casing 14a. The second refrigerant passage 22c passes through a fourth valve device 23d before reaching the second point Y, and then branches off into a fifth refrigerant passage 22f that extends toward the sub-casing 14b. The end of the second refrigerant passage 22c merges with the fourth refrigerant passage 22e. Therefore, the second refrigerant passage 22c connects the first point X and the second point Y via the upstream refrigerant passage 22a, the fourth refrigerant passage 22e, and the third refrigerant passage 22d.

[0034] Fifth refrigerant passage 22f passes through fifth valve device 23e and then communicates with third point V of sub-casing 14b. Additionally, sixth refrigerant passage 22g is drawn out from fourth point W of sub-casing 14b and merges with downstream refrigerant passage 22h.

[0035] By controlling these valve devices 23, the flow direction of the refrigerant in the refrigerant passage 22m in the main casing 14a can be switched between one direction A (see FIG. 3) from the first point to the second point and the opposite other direction B (see FIG. 4). This makes it possible to improve the degree of cooling in parts of the casing 14 (main casing 14a) that previously had poor cooling performance. In addition, since the more the power module is used, the more likely temperature differences are to occur within the casing 14 (main casing 14a), there is an advantage that efficient cooling can be achieved even under such harsh conditions simply by switching the direction of the refrigerant flow without particularly detailed control.

[0036] 3, the valve devices 23 are specifically controlled as follows: first valve device 23a is opened (fully open), second valve device 23b is opened (fully open), third valve device 23c is closed (fully closed), fourth valve device 23d is closed (fully closed), fifth valve device 23e is closed (fully closed), and sixth valve device 23f is opened (fully open). As a result, at the first point X, the upstream refrigerant passage 22a from pump 21 is connected to refrigerant passage 22m in the main casing 14a, and the flow path from the upstream refrigerant passage 22a to the first refrigerant passage 22b is blocked. Furthermore, because the fourth valve device 23d is closed, the flow path of the second refrigerant passage 22c is blocked. At second point Y, downstream refrigerant passage 22h, which is a refrigerant passage returning to the pump, is connected to refrigerant passage 22m in main casing 14a via fourth refrigerant passage 22e and third refrigerant passage 22d, and the flow path from downstream refrigerant passage 22h to second refrigerant passage 22c is blocked. Therefore, the refrigerant flows in one direction A in main casing 14a, sequentially cooling VCU 11 and MCU 12. In FIG. 3, the supply of refrigerant to sub-casing 14b is stopped.

[0037] 4, the first valve device 23a is in a closed state (fully closed state), the second valve device 23b is in a closed state (fully closed state), the third valve device 23c is in an open state (fully open state), the fourth valve device 23d is in an open state (fully open state), the fifth valve device 23e is in a closed state (fully closed state), and the sixth valve device 23f is in an open state (fully open state). As a result, at the first point X, the upstream refrigerant passage 22a from the pump 21 is connected to the first refrigerant passage 22b, and the flow path from the upstream refrigerant passage 22a to the refrigerant passage 22m in the main casing 14a is blocked. Furthermore, the refrigerant passage 22m in the main casing 14a is connected to the second refrigerant passage 22c. At the second point Y, the first refrigerant passage 22b is connected to the refrigerant passage 22m in the main casing 14a via the third refrigerant passage 22d, and the flow path from the first refrigerant passage 22b to the downstream refrigerant passage 22h is blocked. Furthermore, downstream refrigerant passage 22h is connected to second refrigerant passage 22c via fourth refrigerant passage 22e, and the flow path from downstream refrigerant passage 22h to refrigerant passage 22m in main casing 14a is blocked. Therefore, the refrigerant flows in the main casing 14a in direction B, which sequentially cools MCU 12 and VCU 11. In FIG. 4, the supply of refrigerant to sub-casing 14b is stopped.

[0038] 2, a first temperature sensor 26 is provided near a first point X (on the side away from the main casing 14a), and a second temperature sensor 27 is provided near a second point X (on the side away from the main casing 14a). Temperature information acquired by the first temperature sensor 26 and the second temperature sensor 27 is sent to an electronic control unit 40. An inverter cooling control unit 42 performs control to switch the refrigerant flow direction between one direction A and the other direction B based on a temperature difference Tx-Ty between a first point temperature Tx acquired by the first temperature sensor 26 and a second point temperature Ty acquired by the second temperature sensor 27.

[0039] For example, when the temperature difference Tx-Ty is a positive value, the first point temperature Tx is higher than the second point temperature Ty, so the refrigerant flow direction is set to direction A, and cooling of the first point X side is prioritized over cooling of the second point Y side. This is because the temperature of the refrigerant in the refrigerant passage 22 is lower on the side closer to the pump 21. Also, when the temperature difference Tx-Ty is a negative value, the second point temperature Ty is higher than the first point temperature Tx, so the refrigerant flow direction is set to direction B, and cooling of the second point Y side is prioritized over cooling of the first point X side. Note that when the temperature difference Tx-Ty is zero, direction A may be selected as the refrigerant flow direction. This is because direction A has a shorter flow path length than direction B and is easier to route the flow path, so selecting direction A provides better cooling efficiency than selecting direction B.

[0040] Furthermore, when switching the refrigerant flow between one direction A and the other direction B, it is desirable that the inverter cooling control unit 42 first opens all of the valve devices 23 (see, for example, FIG. 5), and then sets the valve devices 23 to a predetermined state corresponding to the state after switching. This is to avoid a situation where the refrigerant flow is switched from one direction A to the other direction B or from the other direction B to one direction A in one go, which could cause refrigerant particles to collide with each other and result in refrigerant stagnation within the inverter 10.

[0041] 3 and 4, the supply of refrigerant into the sub-casing 14b is stopped. However, when cooling the GCU 13, the fifth valve device 23e is opened (fully opened) and the sixth valve device 23f is closed (fully closed), thereby allowing the refrigerant to be supplied into the sub-casing 14b. A case where cooling the GCU 13 is highly necessary may be, for example, when the driving mode set for the vehicle 1 is the parallel driving mode or the series driving mode. In this case, the fifth refrigerant passage 22f is opened to the refrigerant flow path 22n in the sub-casing 14b at the third point V, and the refrigerant flow path 22n in the sub-casing 14b is opened to the downstream refrigerant passage 22h at the fourth point W (although the valve device 23 is not disposed on the fourth point W side in the embodiment, the valve device 23 may be disposed there instead). The refrigerant passing through the fifth refrigerant passage 22f flows into the sub-casing 14b from a third point V, cools the GCU 13, and then flows out of the sub-casing 14b at a fourth point W. The flowing-out refrigerant is sent to the sixth refrigerant passage 22g and the downstream refrigerant passage 22h.

[0042] Furthermore, a case where there is little need to cool the GCU 13 may be assumed, for example, when the driving mode is an EV mode. The fifth valve device 23e is closed (fully closed) and the sixth valve device 23f is opened (fully open) to block the flow path into the sub-casing 14b. In this way, by separating the VCU 11 and MCU 12 from the GCU 13, it is possible to increase the cooling efficiency according to the driving mode.

[0043] Furthermore, when the power switch of the vehicle 1 is turned off (when the ignition is turned off), it is desirable that the inverter cooling control unit 42 set the refrigerant flow in the main casing 14a to one direction A. That is, with the valve device 23 in the state shown in FIG. 3 , the upstream refrigerant passage 22a is opened to the refrigerant passage 22m in the main casing 14a at the first point X, and the downstream refrigerant passage 22h is opened to the refrigerant passage 22m in the main casing 14a at the second point Y. This is because, as described above, the length of the flow path in one direction A is shorter than that in the other direction B, and the flow path can be easily routed, so selecting one direction A provides better cooling efficiency than selecting the other direction B. By switching to one direction A when the power switch is turned off, efficient cooling can begin immediately after startup.

[0044] An example of control of the cooling device 20 is shown in FIG.

[0045] Control starts at t = 0 in Fig. 6. At the start of control, the first valve device 23a is in an open state (fully open state), the second valve device 23b is in an open state (fully open state), the third valve device 23c is in a closed state (fully closed state), and the fourth valve device 23d is in a closed state (fully closed state) (state 0).

[0046] At t=t1, Tx-Ty≧0. Therefore, the valve device 23 continues to be in the same state as state 0. As a result, the refrigerant flow direction becomes unidirectional A (state 1 / unidirectional A state). Note that the fifth valve device 23e and the sixth valve device 23f determine whether to open or close the valve depending on the cooling requirements of the GCU 13 (the same applies to each of the following situations).

[0047] At t=t2, the temperature condition changes and transitions to Tx-Ty<0. In this case, all the valve devices 23 are temporarily opened (fully open) (state 2 / released state). At this time, the fourth valve device 23d is switched to the open state with a predetermined delay from the switching of the other valve devices 23 to the open state, thereby facilitating the discharge of the refrigerant.

[0048] At t=t3, if a predetermined time has elapsed since the open state of State 2 was entered, control is started to switch the refrigerant flow direction to the other direction B. First, the first valve device 23a is set to a valve-closed state (fully closed state) (State 3 / state in the middle of switching from one direction A to the other direction B).

[0049] At t=t4, if a predetermined time has elapsed since State 3 was entered, the second valve device 23b is closed (fully closed). The third valve device 23c is kept open (fully open), and the fourth valve device 23d is kept open (fully open). This causes the refrigerant to flow in other direction B (State 4 / other direction B). The second valve device 23b is switched to the closed state a predetermined time later than the first valve device 23a, thereby facilitating the discharge of the refrigerant.

[0050] Assume that at t=t5, Tx-Ty>0 again occurs. In this case, all valve devices 23 are temporarily opened (fully open) (state 5 / released state). At this time, the second valve device 23b is switched to the open state a predetermined time later than the first valve device 23a, thereby promoting the discharge of the refrigerant.

[0051] At t=t6, if a predetermined time has passed since the open state of State 5 was established, control to switch the refrigerant flow direction to one-way A is initiated. First, the third valve device 23c is closed (fully closed). After a predetermined time has passed, the fourth valve device 23d is closed (fully closed). Furthermore, the first valve device 23a and the second valve device 23b are maintained in an open state (fully open). As a result, the refrigerant flow direction becomes one-way A (State 6 / one-way A state).

[0052] In the above embodiment, one opening of the refrigerant passage 22m in the main casing 14a is defined as a first point X, and the other opening is defined as a second point Y. The first temperature sensor 26 and the second temperature sensor 27 are provided near the openings outside the main casing 14a. However, the first point X and the second point Y may be set to points inside the main casing 14a. The locations of the first point X and the second point Y can be changed as appropriate depending on the specifications. The same applies to the third point V and the fourth point W of the sub-casing 14b. Furthermore, the first temperature sensor 26 and the second temperature sensor 27 may be located as close as possible to the first point X and the second point Y, and an embodiment in which the first temperature sensor 26 and the second temperature sensor 27 are located inside the main casing 14a is also conceivable.

[0053] In the above embodiment, the first point X and the second point Y are set in the main casing 14a that houses the VCU 11 and the MCU 12, but the casing 14 in which the first point X and the second point Y are set is not limited to the above embodiment. For example, the first point X and the second point Y may be set in a casing 14 that houses only the VCU 11, a casing 14 that houses only the MCU 12, a casing 14 that houses only the GCU 13, a casing 14 that houses multiple power modules selected from the VCU 11, the MCU 12, and the GCU 13, or a casing 14 that houses all of the power modules of the VCU 11, the MCU 12, and the GCU 13.

[0054] In each of the above embodiments, a hybrid vehicle is assumed as the vehicle 1, but the hybrid vehicle may be a plug-in hybrid car in which the battery 50 can be charged directly (external charging) using a plug from a household outlet or the like, or the battery 50 can supply power directly to household electrical appliances or the like (external power supply) using a plug. The present invention can also be applied to an electric vehicle (EV) that does not have an engine 4 and has only a motor M as a driving source for traveling. [Explanation of symbols]

[0055] 1 vehicle 4 Engine 5. Generator 10 Inverter 11 Voltage Control Unit (VCU) 12 Motor Control Unit (MCU) 13 Generator Control Unit (GCU) 14 Casing 14a Main casing 14b Sub-casing 20 Cooling device 21 Pump 22 Refrigerant passage 22b First refrigerant passage 22c Second refrigerant passage 23 Valve gear 24 Heat dissipation section (radiator) 25 Motor water jacket M Drive motor (motor)

Claims

1. The vehicle comprises a drive motor and a generator, an inverter including a plurality of power modules, and an inverter cooling device that cools the inverter, the inverter cooling device includes a refrigerant passage through which a refrigerant flows, a pump that supplies the refrigerant to the refrigerant passage, and a valve device that is provided in the refrigerant passage; The refrigerant passage in a casing that houses the plurality of power modules passes through a first point and a second point, and the electric vehicle is equipped with an inverter cooling control unit that controls the valve device to switch the flow direction of the refrigerant in the refrigerant passage between one direction from the first point to the second point and another direction opposite thereto.

2. a first temperature sensor at the first location and a second temperature sensor at the second location; The electric vehicle according to claim 1 , wherein the inverter cooling control unit switches the flow direction of the refrigerant between the one direction and the other direction based on a temperature difference between the first temperature sensor and the second temperature sensor.

3. the first point and the second point are openings of the casing, and a first refrigerant passage and a second refrigerant passage are provided outside the casing to connect the openings; the inverter cooling control unit controls the valve device to open the refrigerant passage from the pump to the refrigerant passage in the casing at the first point side, and to open the refrigerant passage returning to the pump to the refrigerant passage in the casing at the second point side, so that the flow direction of the refrigerant is the one direction; 2. The electric vehicle according to claim 1, wherein, on the first point side, the refrigerant passage from the pump is opened to the first refrigerant passage and the refrigerant passage in the casing is opened to the second refrigerant passage, and, on the second point side, the refrigerant passage returning to the pump is opened to the second refrigerant passage and the first refrigerant passage is opened to the refrigerant passage in the casing, so that the refrigerant flows in the other direction.

4. 4. The electric vehicle according to claim 3, wherein, when switching the refrigerant flow between the one direction and the other direction, the inverter cooling control unit temporarily opens all of the valve devices and then opens the valve devices to a predetermined state corresponding to the switching.

5. 2. The electric vehicle according to claim 1, wherein the power module includes a voltage control unit that controls the voltage supplied to the drive motor, a motor control unit that controls rotation of the drive motor, and a generator control unit that controls power generation by the generator, the first point and the second point being set in a main casing that houses the voltage control unit and the motor control unit, and a sub-casing that houses the generator control unit being provided downstream of the main casing in the flow of refrigerant.

6. an engine is provided as a driving source for traveling, the refrigerant passage in the sub-casing passes through a third point and a fourth point, the third point is connected to the first refrigerant passage or the second refrigerant passage, and the fourth point is connected to the refrigerant passage returning to the pump; When the driving mode is a parallel driving mode in which the vehicle is driven by the driving force of the drive motor and the engine, or a series driving mode in which the drive motor is driven by electric power generated by the generator, the first refrigerant passage or the second refrigerant passage is opened to a flow path in the sub-casing on the third point side, and the flow path in the sub-casing is opened to the refrigerant passage returning to the pump on the fourth point side, 6. The electric vehicle according to claim 5, wherein when the driving mode is an EV driving mode in which the vehicle travels using driving force only from the drive motor, the first refrigerant passage or the second refrigerant passage is blocked from the flow path within the sub-casing on the third point side.

7. 4. The electric vehicle according to claim 3, wherein, when a power switch of the vehicle is turned off, the inverter cooling control unit opens the refrigerant passage from the pump to the refrigerant passage in the casing on the first point side, and opens the refrigerant passage returning to the pump to the refrigerant passage in the casing on the second point side.

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