Control device

Abstract

To provide a technique which can cool an electric motor installed in a wheel with adequate air capacity and at cheap price.SOLUTION: A controller unit 20 comprises: an acquisition part which acquires information of operating condition of an electric motor 14 arranged in a wheel 12; a driving determination part which determines driving of a radiator fan 18 based on the information of the operating condition of the electric motor 14; and a control part which drives the radiator fan 18 according to the determination of the driving determination part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control device for cooling an electric motor provided in a wheel. [Background technology]

[0002] Patent Document 1 discloses a wheel structure for an in-wheel motor of a vehicle that is provided with an in-wheel motor for driving the vehicle in the internal space of the wheel. This wheel structure for an in-wheel motor has a fan that rotates with the wheel and draws outside air into the internal space of the wheel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-157837 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology disclosed in Patent Document 1 has a structure that takes in a large amount of air inside the wheel, so there is a risk that moisture in the air will cause freezing and rust.

[0005] An object of the present invention is to provide a technology that can inexpensively cool an electric motor mounted inside a wheel with an appropriate amount of air. [Means for solving the problem]

[0006] In order to solve the above problem, a control device according to one aspect of the present invention comprises: In-wheel type that serves as the driving force for the vehicle an acquisition unit that acquires information about the operating state of the electric motor; , which is provided to blow air to the radiator that cools the inverter. The radiator fan control system includes a drive determination unit that determines whether to drive the radiator fan, and a control unit that drives the radiator fan in accordance with the determination by the drive determination unit. The air blown from the radiator fan hits the radiator, flows to the left and right, and reaches the electric motor. The drive determination unit When the radiator fan is not driven,When the energy loss of the electric motor according to the estimated temperature rise calculated according to the driving amount of the electric motor exceeds the energy loss of driving the radiator fan, radiator fan Determine the drive. The energy loss of the electric motor in response to the estimated temperature rise is determined by the copper loss that increases in proportion to the temperature rise due to the radiator fan not being driven. The energy loss of the radiator fan is determined by the power consumption of the radiator fan. [Effects of the Invention]

[0007] According to the present invention, a technique can be provided that can inexpensively cool an electric motor provided inside a wheel with an appropriate amount of air. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing an overview of a vehicle equipped with a control device of an embodiment; [Figure 2] FIG. 2 is a diagram illustrating a functional configuration of a vehicle according to an embodiment. [Figure 3] 4 is a flowchart of a cooling process for an electric motor. DETAILED DESCRIPTION OF THE INVENTION

[0009] 1 shows an overview of a vehicle 10 equipped with a control device 20 according to an embodiment. The vehicle 10 includes wheels 12, electric motors 14, on-board sensors 16, a radiator fan 18, and a control device 20. In the vehicle 10 according to the embodiment, each of the front wheels 12 is provided with an electric motor 14. The control device 20 is capable of controlling the driving of each of the electric motors 14 individually.

[0010] The electric motor 14 is disposed on the inner diameter side of the tire, but part or all of the electric motor 14 may be disposed on the suspension side of the wheel 12. In any case, the electric motor 14 is exposed at least from the wheel 12 to the suspension side.

[0011] The on-board sensors 16 include a temperature sensor, a rotation speed sensor, a torque sensor, etc., and detect information related to the operating state of the electric motor 14. The temperature sensor is provided on or near the electric motor 14 and detects the temperature of the electric motor 14. The rotation speed sensor detects the rotation speed of the electric motor 14. The torque sensor detects the output torque of the electric motor 14.

[0012] The radiator fan 18 is provided to send air to a radiator that cools the inverter, and is disposed at the front of the vehicle, for example, behind the front grille. A radiator, inverter, and other components (not shown) are provided behind the radiator fan 18. The air blown from the radiator fan 18 passes through a flow path 22 that flows left and right against the radiator, inverter, and other components, and also reaches the electric motor 14. In this way, the flow path 22 is provided, which communicates from the radiator fan 18 to the electric motor 14 and is formed so that air can pass through.

[0013] In the embodiment, the electric motor 14 that serves as the driving source for the vehicle 10 is an in-wheel type, and since the electric motor 14 is located closer to the ground than a normal on-board type electric motor, it is more likely to generate heat due to radiant heat. In addition, the drive circuit of the electric motor 14 generates heat due to the current flowing during driving. When the vehicle 10 is climbing a slope at a low speed, the rotation of the electric motor 14 is slow, making it difficult to cool the motor 14 and making it more likely to generate heat. It is not easy to provide a separate oil cooling mechanism for the electric motor 14 due to space limitations.

[0014] 2 shows the functional configuration of vehicle 10 according to the embodiment. Each function of vehicle 10 can be configured in terms of hardware using circuit blocks, memory, and other LSIs, and can be realized in terms of software using system software, application programs, etc. loaded into memory. Therefore, it will be understood by those skilled in the art that each function of vehicle 10 can be realized in various forms using only hardware, only software, or a combination thereof, and is not limited to any one of these.

[0015] The control device 20 includes an acquisition unit 24, a drive determination unit 26, and a control unit 28. The acquisition unit 24 acquires information about the operating state of the electric motor 14 from the on-board sensor 16. The acquisition unit 24 may also acquire information about the operating state of the electric motor 14 from the control unit 28. The control unit 28 sends a control command value for the electric motor 14 to the acquisition unit 24 as information about the operating state of the electric motor 14.

[0016] The drive determination unit 26 determines whether to drive the radiator fan 18 based on the information on the operating state of the electric motor 14 received from the acquisition unit 24. The drive determination unit 26 determines whether predetermined operating conditions are met based on the information on the operating state of the electric motor 14, and if the predetermined operating conditions are met, decides to drive the radiator fan 18, and if the predetermined operating conditions are not met, decides not to drive the radiator fan 18. Note that the predetermined operating conditions are for cooling the electric motor 14, and the radiator fan 18 is also driven when the drive conditions for cooling the radiator are met.

[0017] The control unit 28 drives the radiator fan 18 in accordance with the decision made by the drive decision unit 26. As a result, the air blown from the radiator fan 18 passes through the flow path 22 and reaches the electric motor 14, cooling the electric motor 14. In addition, an air flow is created near the electric motor 14, making it easier to cool. By using the radiator fan 18 to cool the electric motor 14, there is no need to provide a new cooling fan, which reduces costs. The control unit 28 arbitrates between cooling the radiator and cooling the electric motor 14, and drives the radiator fan 18 when cooling either one.

[0018] The predetermined operating condition for operating the radiator fan 18 is set so as to be determined based on information relating to the operating state of the electric motor 14. The predetermined operating condition is met when the temperature of the electric motor 14 is equal to or higher than a predetermined temperature. As a result, if the electric motor 14 becomes too hot, the radiator fan 18 can be operated to cool it. Note that the predetermined operating condition may be met when the temperature of the electric motor 14 is equal to or higher than a predetermined temperature and the outside air temperature of the vehicle 10 is equal to or higher than a predetermined value. As a result, unnecessary operation of the radiator fan 18 can be suppressed when the temperature of the driving environment is too low.

[0019] The predetermined operating condition is satisfied when the motor rotation speed of the electric motor 14 is equal to or less than a predetermined number. This allows air to be blown to the electric motor 14 when the rotation speed of the electric motor 14 is too low to draw in air.

[0020] The predetermined operating condition is satisfied when the output torque of the electric motor 14 is equal to or greater than a predetermined torque. This allows the electric motor 14 to be cooled when it generates heat due to high output.

[0021] The predetermined operating condition may be satisfied when the energy loss of the electric motor 14 corresponding to the estimated temperature rise exceeds the energy loss of driving the radiator fan 18. The energy loss of driving the radiator fan 18 is the power consumption of the radiator fan 18. The energy loss of the electric motor 14 corresponding to the estimated temperature rise is copper loss, which increases in proportion to the temperature rise caused by not driving the radiator fan 18. The estimated temperature rise caused by not driving the radiator fan 18 is calculated in accordance with the drive amount of the electric motor 14, and may be calculated based on the most recent drive amount of the electric motor 14.

[0022] It may be determined that the radiator fan 18 is driven when information about the operating state of any one of the plurality of electric motors 14 satisfies a predetermined operating condition. Alternatively, it may be determined that the radiator fan 18 is driven only when information about the operating states of both electric motors 14 respectively satisfy a predetermined operating condition. The above-described plurality of operating conditions may be combined to determine that the radiator fan 18 is driven when a plurality of operating conditions are satisfied. For example, the predetermined operating condition may be satisfied when the motor rotation speed of the electric motor 14 is equal to or lower than a predetermined number and the output torque is equal to or higher than a predetermined torque.

[0023] Fig. 3 is a flowchart of the cooling process of the electric motor 14. The cooling process shown in Fig. 3 is executed at a predetermined cycle. The drive determination unit 26 receives information on the operating state from the acquisition unit 24, and determines whether the temperature of the electric motor 14 is equal to or higher than a predetermined temperature (S10).

[0024] If the temperature of the electric motor 14 is equal to or higher than the predetermined temperature (Y in S10), the drive determination unit 26 determines to drive the radiator fan 18 (S12). The control unit 28 drives the radiator fan 18 in accordance with the determination of the drive determination unit 26 (S14).

[0025] If the temperature of the electric motor 14 is not equal to or higher than the predetermined temperature (N in S10), the drive determination unit 26 determines whether the motor rotation speed of the electric motor 14 is equal to or lower than a predetermined number (S16). If the motor rotation speed of the electric motor 14 is equal to or lower than the predetermined number (Y in S16), the drive determination unit 26 determines to drive the radiator fan 18 (S12).

[0026] If the motor rotation speed of the electric motor 14 is not equal to or less than the predetermined number (N in S16), the drive determination unit 26 determines whether the output torque of the electric motor 14 is equal to or greater than the predetermined torque (S18). If the output torque of the electric motor 14 is equal to or greater than the predetermined torque (Y in S18), the drive determination unit 26 determines to drive the radiator fan 18 (S12).

[0027] If the output torque of the electric motor 14 is not equal to or greater than the predetermined torque (N in S18), the drive determination unit 26 compares the energy loss of the electric motor 14 according to the estimated temperature rise with the energy loss of driving the radiator fan 18 (S20) and determines whether the loss condition is met (S22). The loss condition is met when the energy loss of the electric motor 14 according to the estimated temperature rise exceeds the energy loss of driving the radiator fan 18.

[0028] If the loss condition is met, that is, if the energy loss of the electric motor 14 according to the estimated temperature rise exceeds the energy loss of driving the radiator fan 18 (Y in S22), the drive decision unit 26 decides to drive the radiator fan 18 (S12). If the loss condition is not met (N in S22), the radiator fan 18 is not driven and this process ends.

[0029] It should be understood by those skilled in the art that the embodiments are merely illustrative and that various modifications are possible in the combination of the components, and that such modifications are also within the scope of the present invention.

[0030] In the embodiment, the electric motor 14 is provided only on the front wheels, but the present invention is not limited to this, and the electric motor 14 may be provided on both the front and rear wheels. Even if the electric motor 14 is provided on both the front and rear wheels, a cooling effect can be obtained by driving the radiator fan 18 for the electric motor 14 on the front wheels.

[0031] Furthermore, a pair of radiator fans 18 may be provided on the left and right sides and may be individually drivable, so that when one of the electric motors 14 satisfies a predetermined operating condition, the radiator fan 18 located on the side of the one of the electric motors 14 can be driven to perform cooling. [Explanation of symbols]

[0032] 10 vehicle, 12 wheel, 14 electric motor, 16 on-board sensor, 18 radiator fan, 20 control device, 22 flow path, 24 acquisition unit, 26 drive determination unit, 28 control unit.

Claims

[Claim 1] An acquisition unit that acquires information about the operating state of an in-wheel type electric motor that serves as a driving source for a vehicle; a drive determination unit that determines whether to drive a radiator fan provided to send air to a radiator that cools an inverter, based on information about an operating state of the electric motor; a control unit that drives the radiator fan in accordance with the decision of the drive decision unit, The air blown from the radiator fan hits the radiator, flows left and right, and reaches the electric motor, the drive determination unit determines to drive the radiator fan when an energy loss of the electric motor corresponding to an estimated temperature rise calculated according to a drive amount of the electric motor exceeds an energy loss of driving the radiator fan in a case where the radiator fan is not driven, and The energy loss of the electric motor according to the estimated temperature rise is determined by copper loss that increases according to the temperature rise caused by not driving the radiator fan, The control device is characterized in that the energy loss of the radiator fan is determined by the power consumption of the radiator fan.

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