Cooling System

Abstract

To provide a cooling system capable of reducing cooling unevenness of electrical equipment that supplies a power to a rotary electric machine.SOLUTION: A cooling system comprises: a first cooling circuit that cools down electrical equipment which supplies a power to a rotary electric machine with first cooling liquid; a second cooling circuit that cools down the rotary electric machine and the electrical equipment with second cooling liquid; a heat exchanger that performs heat exchange between the first cooling liquid and the second cooling liquid; a flow rate adjustment mechanism provided on the first cooling circuit to adjust a flow rate of the first cooling liquid flowing in the heat exchanger; and a control device that controls the flow rate adjustment mechanism. The control device controls the flow rate adjustment mechanism so that the flow rate of the first cooling liquid flowing in the heat exchanger at the time when the rotation number of the rotary electric machine is equal to or more than a predetermined rotation number becomes higher than that at the time when the rotation number of the rotary electric machine is less than the predetermined rotation number.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a cooling system. [Background technology]

[0002] Patent document 1 discloses a cooling system that includes a water cooling system that uses cooling water to cool a PCU, which is an electrical device that supplies power to and controls a motor, which is a rotating electric machine; an oil cooling system that cools the motor and PCU with oil; and a heat exchanger that exchanges heat between the cooling water of the water cooling system and the oil of the oil cooling system. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-080432 A Summary of the Invention [Problem to be solved by the invention]

[0004] Here, when the motor rotation speed is high, the motor current value is small, so the heat generated by the PCU is small and the temperature of the cooling water in the water cooling system is unlikely to rise, but iron loss occurs in the motor and the temperature of the oil in the oil cooling system is likely to rise. Therefore, unless the oil temperature is reduced to the maximum extent possible by heat exchange between the cooling water and oil in the heat exchanger, the temperature difference between the cooling water and oil when cooling the PCU will become too large, and there is a risk of significant cooling unevenness in the PCU.

[0005] The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide a cooling system capable of reducing uneven cooling of an electric device that supplies power to a rotating electric machine. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the cooling system of the present invention is a cooling system comprising a first cooling circuit that cools an electrical equipment that supplies power to a rotating electric machine with a first cooling liquid, a second cooling circuit that cools the rotating electric machine and the electrical equipment with a second cooling liquid, a heat exchanger that performs heat exchange between the first cooling liquid and the second cooling liquid, a flow rate adjustment mechanism provided in the first cooling circuit that adjusts the flow rate of the first cooling liquid flowing into the heat exchanger, and a control device that controls the flow rate adjustment mechanism, wherein the control device controls the flow rate adjustment mechanism so that the flow rate of the first cooling liquid flowing into the heat exchanger when the rotation speed of the rotating electric machine is equal to or greater than a predetermined rotation speed is greater than the flow rate of the first cooling liquid flowing into the heat exchanger when the rotation speed of the rotating electric machine is less than the predetermined rotation speed.

[0007] This allows the temperature of the second cooling liquid to be reduced as much as possible through heat exchange between the first and second cooling liquids in the heat exchanger, thereby reducing the temperature difference between the first and second cooling liquids when cooling the electrical equipment, and reducing uneven cooling of the electrical equipment.

[0008] In addition, in the above, the flow rate control mechanism may be a flow rate control valve capable of adjusting a flow rate of the first cooling liquid flowing through a first path for supplying the first cooling liquid to the electrical equipment via the heat exchanger, and a flow rate of the first cooling liquid flowing through a second path for supplying the first cooling liquid to the electrical equipment without passing through the heat exchanger.

[0009] As a result, the flow control valve can increase the flow rate of the first cooling liquid flowing through the first path for supplying the first cooling liquid to an electrical device via a heat exchanger, thereby making it possible to minimize the temperature of the second cooling liquid through heat exchange between the first cooling liquid and the second cooling liquid in the heat exchanger.

[0010] In the above, a direction in which the first cooling liquid flows when cooling the electric device and a direction in which the second cooling liquid flows when cooling the electric device may be opposite to each other.

[0011] This makes it possible to reduce uneven cooling of the electric device caused by temperature deviation in the flow directions of the first and second cooling liquids relative to the electric device. Effect of the Invention

[0012] The cooling system of the present invention has the advantage of being able to reduce the temperature difference between the first coolant and the second coolant when cooling an electrical equipment that supplies power to a rotating electric machine, thereby reducing uneven cooling of the electrical equipment. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a cooling system for a vehicle according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing a cooling structure for a power card provided in a PCU. [Diagram 3] FIG. 3 is a diagram showing a state in which the switching pattern of the first switching valve and the second switching valve is pattern 2 in the first cooling circuit. [Figure 4] FIG. 4 is a diagram showing a state in which the switching pattern of the first switching valve and the second switching valve is pattern 3 in the first cooling circuit. [Diagram 5] FIG. 5 is a diagram showing a map of switching patterns of the first switching valve and the second switching valve with respect to the MG rotation speed and the MG torque. [Figure 6] FIG. 6 is a flowchart showing an example of selection control of the switching pattern of the first switching valve and the second switching valve, which is performed by the ECU. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of a vehicle cooling system according to the present invention will be described. Note that the present invention is not limited to this embodiment. The vehicle cooling system according to the embodiment can be applied to, for example, a hybrid vehicle equipped with an internal combustion engine and a motor as a power source for driving the drive wheels, or an electric vehicle equipped with a motor as the power source.

[0015] Fig. 1 is a schematic diagram showing the configuration of a vehicle cooling system 100 according to an embodiment. As shown in Fig. 1, the vehicle cooling system 100 according to the embodiment includes a first cooling circuit 1 in which LLC (Long Life Coolant) circulates as a first coolant for cooling a PCU (Power Control Unit) 4, and a second cooling circuit 2 in which lubricating oil circulates as a second coolant for cooling a rotating electric machine 22 and the PCU 4. The lubricating oil, which is the second coolant, has higher insulating properties than the LLC, which is the first coolant, and is also used to lubricate the rotating electric machine 22 and the like.

[0016] In the first cooling circuit 1, a first electric pump 11, a reserve tank 12, an oil cooler 3 which is a heat exchanger, a PCU 4, a radiator 13, a first switching valve 14, and a second switching valve 15 are arranged, and each of them is connected by piping. The oil cooler 3 is also used in the second cooling circuit 2, and heat exchange is possible in the oil cooler 3 between the LLC flowing in the first cooling circuit and the lubricating oil flowing in the second cooling circuit. In the first cooling circuit 1, the LLC is circulated within the first cooling circuit 1 by operating the first electric pump 11.

[0017] 1 indicate paths through which LLC flows in the first cooling circuit 1, and dashed lines in Fig. 1 indicate paths through which LLC does not flow in the first cooling circuit 1. In the first cooling circuit 1, a path R11 from the first electric pump 11 to the reserve tank 12, a path R12 from the reserve tank 12 to the first switching valve 14, a path R13 from the first switching valve 14 to the oil cooler 3, a path R14 from the first switching valve 14 to the second switching valve 15, a path R15 from the oil cooler 3 to the second switching valve 15, a path R16 from the second switching valve 15 to the PCU 4, a path R17 from the PCU 4 to the radiator 13, and a path R18 from the radiator 13 to the first electric pump 11 are formed. In FIG. 1, in the first cooling circuit 1, by operating the first electric pump 11, the LLC circulates in the following order, starting from the first electric pump 11, through the first electric pump 11, the reserve tank 12, the first switching valve 14, the oil cooler 3, the second switching valve 15, the PCU 4, and the radiator 13.

[0018] The first switching valve 14 is configured as a three-way valve having a first port 14a, a second port 14b, and a third port 14c, which are inlets and outlets for fluid in three directions. The first switching valve 14 is configured to selectively switch between a state in which the first port 14a communicates with the second port 14b, a state in which the first port 14a communicates with the third port 14c, and a state in which the first port 14a communicates with both the second port 14b and the third port 14c. The first port 14a is connected to the reserve tank 12 by a pipe that forms a flow path R12. The second port 14b is connected to the oil cooler 3 by a pipe that forms a flow path R13. The third port 14c is connected to the first port 15a of the second switching valve 15 by a pipe that forms a flow path R14.

[0019] Therefore, the first switching valve 14 selectively switches between a state in which the LLC that has flowed into the first switching valve 14 from the reserve tank 12 through the flow path R12 flows into the oil cooler 3 through the flow path R13, a state in which the LLC flows into the second switching valve 15 through the flow path R14, and a state in which a portion of the LLC flows into the oil cooler 3 through the flow path R13 and the remainder flows into the second switching valve 15 through the flow path R14. The switching operation of the first switching valve 14 is performed using a drive mechanism such as an actuator controlled by the ECU 5, for example.

[0020] The second switching valve 15 is configured as a three-way valve having a first port 15a, a second port 15b, and a third port 15c which are inlets and outlets for fluid in three directions. The second switching valve 15 is configured to selectively switch between a state in which the first port 15a communicates with the third port 15c, a state in which the second port 15b communicates with the third port 15c, and a state in which both the first port 15a and the second port 15b communicate with the third port 15c. As described above, the first port 15a is connected to the third port 14c of the first switching valve 14 by a pipe forming a flow path R14. The second port 15b is connected to the oil cooler 3 by a pipe forming a flow path R15. The third port 15c is connected to the PCU 4 by a pipe forming a flow path R16 so as to communicate with a first cooling path 41 described later.

[0021] Therefore, the second switching valve 15 selectively switches to one of the following states: a state in which the LLC flowing from the first switching valve 14 through the flow path R14 into the second switching valve 15 flows through the flow path R16 into the first cooling path 41 of the PCU 4; a state in which the LLC flowing from the oil cooler 3 through the flow path R15 into the second switching valve 15 flows through the flow path R16 into the first cooling path 41 of the PCU 4; and a state in which the LLC flowing from the first switching valve 14 through the flow path R14 into the second switching valve 15 and the LLC flowing from the oil cooler 3 through the flow path R15 into the second switching valve 15 join together, and the joined LLC flows through the flow path R16 into the first cooling path 41 of the PCU 4. The switching operation of the second switching valve 15 is performed, for example, by using a driving mechanism such as an actuator controlled by the ECU 5.

[0022] In the cooling system 100 according to the embodiment, the first switching valve 14 and the second switching valve 15 function as flow rate adjustment valves capable of adjusting the flow rate of LLC flowing through a first path (paths R13, R15, R16) for supplying LLC from the reserve tank 12 to the first cooling path 41 of the PCU 4 via the oil cooler 3, and the flow rate of LLC flowing through a second path (paths R14, R16) for supplying LLC from the reserve tank 12 to the first cooling path 41 of the PCU 4 without passing through the oil cooler 3, respectively, and constitute a flow rate adjustment mechanism. As a result, the first switching valve 14 and the second switching valve 15 can increase the flow rate of LLC flowing through the first path (paths R13, R15, R16), for example, to maximize the temperature of the lubricating oil by heat exchange between the LLC and the lubricating oil in the oil cooler 3.

[0023] In the second cooling circuit 2, a second electric pump 21, an oil cooler 3, a PCU 4, a rotating electric machine 22, and an oil pan 23 are arranged, and each of them is connected by piping. Then, by operating the second electric pump 21, the lubricating oil circulates in the second cooling circuit 2. The arrows shown by the dashed dotted lines in FIG. 1 indicate the paths through which the lubricating oil flows in the second cooling circuit 2. In the second cooling circuit 2, a flow path R21 from the second electric pump 21 to the oil cooler 3, a flow path R22 from the oil cooler 3 to the PCU 4, a flow path R23 from the PCU 4 to the rotating electric machine 22, a flow path R24 from the rotating electric machine 22 to the oil pan 23, and a flow path R25 from the oil pan 23 to the second electric pump 21 are formed. In FIG. 1, in the second cooling circuit 2, by operating the second electric pump 21, lubricating oil circulates in the following order, starting from the second electric pump 21, through the second electric pump 21, the oil cooler 3, the PCU 4, the rotating electric machine 22, and the oil pan 23.

[0024] Fig. 2 is a diagram showing a cooling structure for the power card 40 provided in the PCU 4. Fig. 2 shows the PCU 4 as viewed from the top, side, and bottom.

[0025] The PCU4 is an electric device that supplies power to the rotating electric machine 22, and is configured by arranging a power card 40 and the like in a case that forms the outer shell of the PCU4. The PCU4 is driven by the power of a battery mounted on the vehicle and controls the operation of the rotating electric machine 22. The rotating electric machine 22 generates power for driving the drive wheels of the vehicle using the power of the battery according to a control signal from the PCU4. The PCU4 is arranged on the upper side of the rotating electric machine 22, and the PCU4 and the rotating electric machine 22 are integrally configured to form a mechanically and electrically integrated structure. When the PCU4 and the rotating electric machine 22 are thus formed into a mechanically and electrically integrated structure, the heat of the rotating electric machine 22 may be transferred to the case of the PCU4, causing the temperature of the lower surface of the power card 40 to rise. In the cooling system 100 according to the embodiment, a cooling structure is provided in which the upper and lower surfaces of the power card 40 are cooled by coolant (LLC and lubricating oil) in the case of the PCU4.

[0026] In the PCU 4, the power card 40 is configured by arranging a plurality of semiconductor elements 400a, 400b, and 400c in a line in a plane with a space therebetween. A first heat dissipation member 401 is provided on the upper side of the power card 40, which is thermally connected to the upper surfaces of the plurality of semiconductor elements 400a, 400b, and 400c and dissipates heat transferred from the plurality of semiconductor elements 400a, 400b, and 400c. A second heat dissipation member 402 is provided on the lower side of the power card 40, which is thermally connected to the lower surfaces of the plurality of semiconductor elements 400a, 400b, and 400c and dissipates heat transferred from the plurality of semiconductor elements 400a, 400b, and 400c. Inside the case of PCU4, a first cooling path 41 through which LLC flows to cool a first heat dissipation member 401 on the upper side of the power card 40 and a second cooling path 42 through which lubricating oil flows to cool a second heat dissipation member 402 on the lower side of the power card 40 are formed and separated by a sealing member 403.

[0027] Incidentally, the LLC flows into the first cooling path 41 from the third port 15c of the second switching valve 15 through the flow path R16, and the LLC after cooling the first heat dissipation member 401 is sent from the first cooling path 41 through the flow path 17 to the radiator 13, so that it can be said that the first cooling path 41 constitutes a part of the first cooling circuit. Also, the lubricating oil flows into the second cooling path 42 from the oil cooler 3 through the flow path R22, and the lubricating oil after cooling the second heat dissipation member 402 is sent from the second cooling path 42 through the flow path R23 to the rotating electric machine 22, so that it can be said that the second cooling path 42 constitutes a part of the second cooling circuit.

[0028] In the cooling system 100 according to the embodiment, the flow direction of the LLC flowing through the first cooling path 41 and the flow direction of the lubricant flowing through the second cooling path 42 are opposite to the arrangement direction of the multiple semiconductor elements 400a, 400b, and 400c in the power card 40. That is, in the first cooling path 41, the LLC flows so as to cool the semiconductor element 400a, the semiconductor element 400b, and the semiconductor element 400c in that order. On the other hand, in the second cooling path 42, the lubricant flows so as to cool the semiconductor element 400c, the semiconductor element 400b, and the semiconductor element 400a in that order. Therefore, the temperature of the LLC flowing through the first cooling path 41 increases from the semiconductor element 400a toward the semiconductor element 400c, and the temperature of the lubricant flowing through the second cooling path 42 increases from the semiconductor element 400c toward the semiconductor element 400a. This makes it possible to reduce uneven cooling of the power card 40 (multiple semiconductor elements 400a, 400b, 400c) caused by temperature deviations in the flow directions of the LLC and lubricant relative to the power card 40 (multiple semiconductor elements 400a, 400b, 400c).

[0029] Data from various sensors is input to the ECU 5. For example, data such as the MG rotational speed, which is the rotational speed of the rotating electric machine 22, and the MG torque, which is the torque of the rotating electric machine 22, are input. Note that the MG torque is correlated with the MG current value, which is the value of the current that rotationally drives the rotating electric machine 22, and the larger the MG torque, the larger the MG current value. Therefore, in this embodiment, data on the MG current value is input to the ECU 5 as data related to the MG torque.

[0030] In the cooling system 100 according to the embodiment, the ECU 5 performs switching operations of the first switching valve 14 and the second switching valve 15 based on the MG rotation speed and the MG torque (MG current value) of the rotating electric machine 22. In the cooling system 100 according to the embodiment, three patterns, pattern 1, pattern 2, and pattern 3, are set as switching patterns of the first switching valve 14 and the second switching valve 15.

[0031] In pattern 1, as shown in FIG. 1, the first switching valve 14 is switched to a state in which the LLC that flows from the reserve tank 12 through flow path R12 into the first switching valve 14 flows into the oil cooler 3 through flow path R13, and the second switching valve 15 is switched to a state in which the LLC that flows from the oil cooler 3 through flow path R15 into the second switching valve 15 flows into the first cooling path 41 of the PCU 4 through flow path R16.

[0032] In pattern 2, as shown in FIG. 3, the first switching valve 14 is switched to a state in which the LLC that flows from the reserve tank 12 through flow path R12 into the first switching valve 14 flows through flow path R14 into the second switching valve 15, and the second switching valve 15 is switched to a state in which the LLC that flows from the first switching valve 14 through flow path R14 into the second switching valve 15 flows through flow path R16 into the first cooling path 41 of the PCU4.

[0033] In pattern 3, as shown in FIG. 4, the first switching valve 14 is switched to a state in which a portion of the LLC that flows from the reserve tank 12 through flow path R12 into the first switching valve 14 flows into the oil cooler 3 through flow path R13, and the remaining LLC from the reserve tank 12 flows into the second switching valve 15 through flow path R14, and the second switching valve 15 is switched to a state in which the LLC that flows from the first switching valve 14 through flow path R14 into the second switching valve 15 and the LLC that flows from the oil cooler 3 through flow path R15 into the second switching valve 15 are merged, and the merged LLC flows into the first cooling path 41 of the PCU 4 through flow path R16.

[0034] FIG. 5 is a diagram showing a map of switching patterns of the first switching valve 14 and the second switching valve 15 with respect to the MG rotation speed and the MG torque.

[0035] As shown in FIG. 5, in the operating state of the rotating electric machine 22 where the MG rotation speed is equal to or higher than a predetermined rotation speed N1 and the MG torque is lower than a predetermined torque T1, in other words, in the operating state of the rotating electric machine 22 at a high MG rotation speed and a low MG torque, pattern 1 is selected as the switching pattern of the first switching valve 14 and the second switching valve 15. In the operating state of the rotating electric machine 22 at a high MG rotation speed and a low MG torque, the MG current value is small, so the heat generated by the power card 40 (semiconductor elements 400a, 400b, 400c) of the PCU 4 is small, and the temperature of the LLC is unlikely to rise, and iron loss occurs in the rotating electric machine 22, so the temperature of the lubricating oil is likely to rise. Therefore, it is necessary to reduce the temperature of the lubricating oil as much as possible by heat exchange with the LLC in the oil cooler 3. Therefore, in the operating state of the rotating electric machine 22 at a high MG rotation speed and a low MG torque, pattern 1 is selected, which allows all of the LLC from the reserve tank 12 to flow into the oil cooler 3. This reduces the temperature difference between the LLC and the lubricant when the PCU 4 cools the first heat dissipation member 401 and the second heat dissipation member 402, thereby reducing uneven cooling of the power card 40 (multiple semiconductor elements 400a, 400b, 400c).

[0036] 5, in an operating state of the rotating electric machine 22 in which the MG rotational speed is less than a predetermined rotational speed N1 and the MG torque is less than a predetermined torque T1, in other words, in an operating state of the rotating electric machine 22 at a low MG rotational speed and a low MG torque, the pattern 2 is selected as a switching pattern of the first switching valve 14 and the second switching valve 15. In an operating state of the rotating electric machine 22 at a low MG rotational speed and a low MG torque, the temperatures of both the LLC and the lubricant are unlikely to rise. Therefore, the pattern 2 is selected, which allows all of the LLC from the reserve tank 12 to flow directly into the first cooling path 41 of the PCU 4 without heat exchange with the lubricant in the oil cooler 3. This makes it possible to reduce the temperature difference between the LLC and the lubricant when the first heat dissipation member 401 and the second heat dissipation member 402 are cooled by the PCU 4, and to reduce uneven cooling of the power card 40 (multiple semiconductor elements 400a, 400b, 400c).

[0037] 5, in the operating state of the rotating electric machine 22 where the MG rotation speed is less than a predetermined rotation speed N1 and the MG torque is equal to or greater than a predetermined torque T1, in other words, in the operating state of the rotating electric machine 22 at a low MG rotation speed and a high MG torque, pattern 3 is selected as the switching pattern of the first switching valve 14 and the second switching valve 15. In the operating state of the rotating electric machine 22 at a low MG rotation speed and a high MG torque, the MG current value is large, so the heat generated by the power card 40 (semiconductor elements 400a, 400b, 400c) of the PCU 4 is large, and the temperature of the LLC is likely to rise, and iron loss is generated in the rotating electric machine 22, and the temperature of the lubricating oil is also likely to rise. Therefore, pattern 3 is selected, which allows the remaining LLC from the reserve tank 12 to flow directly into the first cooling path 41 of the PCU 4 without passing through the oil cooler 3 while a part of the LLC from the reserve tank 12 is heat-exchanged with the oil cooler 3 to lower the temperature of the lubricating oil. This reduces the temperature difference between the LLC and the lubricant when the PCU 4 cools the first heat dissipation member 401 and the second heat dissipation member 402, thereby reducing uneven cooling of the power card 40 (multiple semiconductor elements 400a, 400b, 400c).

[0038] In the map of the switching patterns of the first switching valve 14 and the second switching valve 15 shown in FIG. 5, the MG torque may be replaced with the MG current value.

[0039] Fig. 6 is a flowchart showing an example of selection control of the switching pattern of the first switching valve 14 and the second switching valve 15, which is performed by the ECU 5. Note that in the switching control shown in Fig. 6, an MG current value is used instead of an MG torque.

[0040] First, in step S1, the ECU 5 judges whether or not the current MG current value is equal to or greater than a predetermined current value. When the ECU 5 judges that the current MG current value is equal to or greater than the predetermined current value (Yes in step S1), the ECU 5 selects pattern 3 as the switching pattern of the first switching valve 14 and the second switching valve 15 in step S2, and ends a series of controls. On the other hand, when the ECU 5 judges that the current MG current value is not equal to or greater than the predetermined current value (No in step S1), the ECU 5 judges whether or not the current MG rotation speed is equal to or greater than a predetermined rotation speed in step S3. When the ECU 5 judges that the current MG rotation speed is equal to or greater than the predetermined rotation speed, the ECU 5 selects pattern 1 as the switching pattern of the first switching valve 14 and the second switching valve 15 in step S4, and ends a series of controls. On the other hand, when the ECU 5 judges that the current MG rotation speed is not equal to or greater than the predetermined rotation speed (No in step S3), the ECU 5 selects pattern 2 as the switching pattern of the first switching valve 14 and the second switching valve 15 in step S5, and ends a series of controls.

[0041] In the cooling system 100 according to the embodiment, the switching pattern of the first switching valve 14 and the second switching valve 15 is selected according to the operating state of the rotating motor 22, in other words, the MG rotation speed and the MG torque (MG current value), thereby making it possible to reduce the temperature difference between the LLC and the lubricant when the PCU 4 cools the first heat dissipation member 401 and the second heat dissipation member 402, and to reduce uneven cooling of the power card 40 (multiple semiconductor elements 400a, 400b, 400c). [Explanation of symbols]

[0042] 1 First cooling circuit 2 Second cooling circuit 3. Oil cooler 4 PCU 5 ECU 11 First electric pump 12 Reserve tank 13 Radiator 14 First changeover valve 14a First port 14b Second Port 14c Third Port 15 Second changeover valve 15a First Port 15b Second Port 15c Third Port 21 Second electric pump 22 Rotating Electric Machine 23 Oil pan 40 Power Card 400a Semiconductor element 400b Semiconductor device 400c Semiconductor Device 401 First heat dissipation member 402 Second heat dissipation member 403 Sealing material

Claims

1. a first cooling circuit that cools an electric device that supplies power to the rotating electric machine with a first coolant; a second cooling circuit that cools the rotating electric machine and the electric device with a second cooling liquid; a heat exchanger that performs heat exchange between the first cooling liquid and the second cooling liquid; a flow rate adjusting mechanism provided in the first cooling circuit and configured to adjust a flow rate of the first cooling liquid flowing into the heat exchanger; A control device for controlling the flow rate adjustment mechanism; A cooling system comprising: the first cooling circuit has a first path for supplying the first cooling liquid from a reserve tank to the electrical equipment via the heat exchanger, and a second path for supplying the first cooling liquid from the reserve tank to the electrical equipment without passing through the heat exchanger, the flow rate adjustment mechanism is a flow rate adjustment valve capable of adjusting a flow rate of the first cooling liquid flowing through the first path and a flow rate of the first cooling liquid flowing through the second path, The control device controls the flow rate control valve so that when the rotation speed of the rotating electric machine is equal to or greater than a predetermined rotation speed, the first cooling liquid flows into the electric equipment through only the first path from the reserve tank, and when the rotation speed of the rotating electric machine is less than the predetermined rotation speed, the first cooling liquid that has passed through the first path from the reserve tank and the first cooling liquid that has passed through the second path from the reserve tank flow into the electric equipment, so that the flow rate of the first cooling liquid flowing into the heat exchanger when the rotation speed of the rotating electric machine is equal to or greater than a predetermined rotation speed is greater than the flow rate of the first cooling liquid flowing into the heat exchanger when the rotation speed of the rotating electric machine is less than the predetermined rotation speed.

2. 2. The cooling system according to claim 1, wherein a direction in which the first cooling liquid flows when cooling the electrical device is opposite to a direction in which the second cooling liquid flows when cooling the electrical device.

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