Liquid immersion cooling apparatus for motor-driven power steering system of vehicle

Abstract

The present invention relates to a liquid immersion cooling apparatus for a motor-driven power steering system of a vehicle, the apparatus having a circulation pump controller that drives an immersion refrigerant circulation pump so as to circulate an immersion refrigerant if it is determined that an electric steering motor driving value exceeds a motor heating threshold value, so that the immersion refrigerant comes into direct contact with a motor driving element (for example, an FET) of a motor driver mounted on a circuit board constituting a steering controller immersed in a liquid immersion tank, and thus heat from the corresponding motor driving element (for example, the FET) is dissipated. According to the present invention, the immersion refrigerant comes into direct contact with the motor driving element (for example, the FET) of the motor driver so that heat from the corresponding motor driving element (for example, the FET) is dissipated, and thus heat dissipation performance remarkably superior to that of an air-cooled heat dissipation technology using a conventional heating plate or an indirect liquid-cooled heat dissipation technology using a conventional heat pipe can be expected.

Description

Liquid immersion cooling device for vehicle electric power steering system

[0001] The present invention relates to an electric power steering device, and more particularly, to a liquid immersion cooling device for an electric power steering device.

[0002] The present invention is a result of the Gangwon-do e-mobility R&D support project carried out with the support of Gangwon Techno Park with financial resources from Gangwon-do (Gangwon Techno Park No. 2023-020-001).

[0003] An electric power steering system for a vehicle controls the electricity supplied from the vehicle's battery to the steering controller to generate assistance that assists the steering force required when the driver steers the handwheel.

[0004] Fig. 1 is an embodiment showing a conventional electric steering device (100') for a vehicle.

[0005] The conventional electric steering device (100') for a vehicle shown in Fig. 1 is configured to include a handwheel sensor (110'), an electric steering motor (120'), and a steering controller (130').

[0006] The above handwheel sensor (110') is configured as a TOS (Torque Only Sensor) that detects only the handwheel torque when the driver adjusts the steering angle of the handwheel (111') or as a TAS (Torque and Angle Sensor) that detects both the steering angle and the handwheel torque.

[0007] The above electric steering motor (120') is driven by a driving signal that controls the motor current to generate an assist force that rotates the handwheel (111').

[0008] The above steering controller (130') receives a vehicle speed signal and the handwheel torque detected by the handwheel sensor (110') or both the steering angle and handwheel torque, and a motor current signal or a motor rotation speed (RPM) signal detected from the electric steering motor (120'), and outputs a driving signal for controlling the motor current applied to the electric steering motor (120') based on the handwheel torque value and motor current value classified in advance for steering angle control according to the vehicle speed range.

[0009] The above steering controller (130') is an ECU (Electronic Control Unit) for steering control, and is composed of a circuit board equipped with a sensor (131'), an MCU (Microcontroller Unit) (132'), a power connector (POWER) (133'), a CAN communication interface (CAN I / F) (134'), and a motor driver (Motor Driver) (135').

[0010] The above sensor (131') detects the detection signal of the handwheel sensor (110') and the motor current signal or motor rotation speed (RPM) signal detected from the electric steering motor (120').

[0011] The above MCU (132') outputs a motor current control signal applied to the electric steering motor (120') based on the pre-classified handwheel torque value and motor current value for steering angle control according to the above-mentioned vehicle speed range.

[0012] The above power connector (133') receives driving power (VCC) from the vehicle's battery.

[0013] The above CAN communication interface (134') receives a vehicle speed signal required for steering control through vehicle CAN (Controller Area Network) communication.

[0014] The above motor driver (135') is configured to include a motor driving element, such as an FET (field effect transistor), which converts electricity supplied from the vehicle's battery into a low-voltage / high-current driving signal and outputs it according to a motor current control signal input from the MCU (132'), and is mounted on a circuit board constituting the steering controller (130').

[0015] In a conventional electric steering device (100') for a vehicle configured as described above, when the steering controller (130') outputs a driving signal for controlling the motor current as described above, the electric steering motor (120') is driven to generate an assist force that rotates the handwheel (111'), and the vehicle's wheels can be easily steered according to the driver's will by the assist force generated in this way.

[0016] Meanwhile, when the motor driver (135') converts the electricity supplied from the vehicle's battery into a low-voltage / high-current driving signal according to the motor current control signal input of the MCU (132') and outputs it, and the electric steering motor (120') is driven, in particular, the motor driving element (e.g., FET) mounted on the circuit board constituting the steering controller (130') overheats, so in the past, an air-cooling heat dissipation technology using a heating plate to prevent overheating of the motor driving element (e.g., FET) mounted on the circuit board has been developed (see Patent Document 1 (KR 10-1511596 B1)), or an indirect liquid-cooling heat dissipation technology using a heat pipe formed with a fluid-filled pipe body as a heat exchange means of the circuit board (see Patent Document 2 (KR 10-1374947 B1)).

[0017] However, the air-cooling heat dissipation technology using the above-mentioned heating plate has implementation and price issues, such as the heat dissipation efficiency increasing in proportion to the heat dissipation area and the need for a material with excellent heat conductivity, and the indirect liquid-cooling heat dissipation technology has the advantage of relatively superior heat dissipation performance compared to the air-cooling heat dissipation technology using the heating plate, but has limitations in increasing heat dissipation performance because it does not dissipate heat through direct contact with the motor driving element (e.g., FET) of the motor driver (135') mounted on the circuit board.

[0018] The present invention is to solve the conventional problems as described above, and an object of the present invention is to provide a liquid immersion cooling device for a vehicle electric power steering device, which, when it is determined that an electric power steering motor driving value exceeds a motor heat generation threshold value, drives an immersion refrigerant circulation pump by a circulation pump controller to circulate an immersion refrigerant, thereby bringing the immersion refrigerant directly into contact with a motor drive element (e.g., FET) of a motor driver mounted on a circuit board constituting a steering controller immersed in an immersion tank, thereby performing heat dissipation for the motor drive element (e.g., FET).

[0019] In order to achieve the above object of the present invention, a liquid immersion cooling device for a vehicle electric power steering device according to the present invention comprises: a handwheel sensor configured with a TOS (Torque Only Sensor) that detects only handwheel torque when a handwheel steering angle is adjusted by a driver, or a TAS (Torque and Angle Sensor) that detects both a steering angle and a handwheel torque; an electric steering motor that generates an assist force for rotating a handwheel by being driven by a drive signal that controls a motor current; And a steering controller for outputting a driving signal for controlling the motor current applied to the electric steering motor based on the handwheel torque value and the motor current value classified in advance for steering angle control according to the vehicle speed range when inputting the vehicle speed signal and the handwheel torque detected by the handwheel sensor or both the steering angle and the handwheel torque, and the motor current signal or the motor rotation speed (RPM) signal detected from the electric steering motor, wherein a motor driver mounted on a circuit board constituting the steering controller is immersed in an immersion tank and the immersion refrigerant contained in the cooling tank is circulated by operating an immersion refrigerant circulation pump, and when the electric steering motor driving value converted using the handwheel torque detected from the handwheel sensor and the electric steering motor driving value converted using the driving signal applied to the electric steering motor are compared with predetermined motor heating values, if it is determined that the electric steering motor driving value exceeds a motor heating threshold value, the circulation The pump controller drives the immersion refrigerant circulation pump to circulate the refrigerant, thereby bringing the immersion refrigerant into direct contact with the motor drive element (e.g., FET) of the motor driver immersed in the immersion tank, thereby performing heat dissipation for the motor drive element (e.g., FET).

[0020] In the liquid immersion cooling device for a vehicle electric power steering device according to the present invention, the circulation pump controller is characterized in that it drives the liquid immersion refrigerant circulation pump (130) to circulate refrigerant when it is determined that the electric power steering motor driving value converted using the handwheel torque detected from the handwheel sensor corresponds to a predetermined motor heat generation value and the electric power steering motor driving value exceeds a motor heat generation threshold value.

[0021] In the liquid immersion cooling device for a vehicle electric steering device according to the present invention, the circulation pump controller is characterized in that it drives the liquid immersion refrigerant circulation pump to circulate refrigerant when it is determined that the electric steering motor driving value converted using a driving signal applied to the electric steering motor corresponds to a predetermined motor heating value and the electric steering motor driving value exceeds a motor heating threshold value.

[0022] In a liquid immersion cooling device for a vehicle electric steering device according to the present invention, the circulation pump controller is characterized in that it measures the PWM signal pulse width of a driving signal applied to the electric steering motor and converts the electric steering motor driving value.

[0023] In a liquid immersion cooling device for a vehicle electric steering device according to the present invention, the circulation pump controller is characterized in that it is mounted on a circuit board that constitutes the steering controller as a steering control ECU.

[0024] In the liquid immersion cooling device for a vehicle electric steering device according to the present invention, the circulation pump controller is characterized in that it is mounted on an independent circuit board different from the circuit board that constitutes the steering controller as a steering control ECU.

[0025] According to the present invention, heat dissipation for a motor driving element (e.g., FET) of a motor driver is performed by directly contacting the immersion refrigerant with the motor driving element, so that significantly improved heat dissipation performance can be expected compared to air cooling heat dissipation technology using a conventional heating plate or indirect liquid cooling heat dissipation technology using a conventional heat pipe.

[0026] Figure 1 is a block diagram showing the configuration of a motor control device of a typical electric power steering device for a vehicle.

[0027] Figure 2 is an embodiment showing the configuration of a liquid immersion cooling device for a vehicle electric steering device according to the present invention.

[0028] Fig. 3 is an embodiment explaining the control operation of the circulation pump controller shown in Fig. 2.

[0029] Fig. 4 is a graph explaining the control operation of the circulation pump controller shown in (c) of Fig. 3.

[0030] Hereinafter, embodiments of the present invention will be described in more detail with reference to the attached drawings.

[0031] The liquid immersion cooling device for a vehicle electric steering device according to the present invention described below is not limited to the following embodiments, and has the technical spirit to the extent that anyone with ordinary knowledge in the relevant technical field can modify and implement it without departing from the gist of the technology claimed in the claims.

[0032] Referring to FIG. 2, a liquid immersion cooling device (100) for a vehicle electric power steering device according to the present invention is used in a vehicle electric power steering device (100') (see FIG. 1) that includes a handwheel sensor (110'), an electric steering motor (120'), and a steering controller (130'), and is configured to include an immersion tank (110), a cooling tank (120), an immersion refrigerant circulation pump (130), and a circulation pump controller (140).

[0033] Referring to FIG. 1, the handwheel sensor (110') is configured as a TOS (Torque Only Sensor) that detects only the handwheel torque when the driver adjusts the steering angle of the handwheel (111'), or as a TAS (Torque and Angle Sensor) that detects both the steering angle and the handwheel torque.

[0034] The above electric steering motor (120') is driven by a driving signal that controls the motor current to generate an assist force that rotates the handwheel (111').

[0035] The above steering controller (130') receives a vehicle speed signal and the handwheel torque detected by the handwheel sensor (110') or both the steering angle and handwheel torque, and a motor current signal or a motor rotation speed (RPM) signal detected from the electric steering motor (120'), and outputs a driving signal for controlling the motor current applied to the electric steering motor (120') based on the handwheel torque value and motor current value classified in advance for steering angle control according to the vehicle speed range.

[0036] The above steering controller (130') is an ECU (Electronic Control Unit) for steering control, and is composed of a circuit board equipped with a sensor (131'), an MCU (Microcontroller Unit) (132'), a power connector (POWER) (133'), a CAN communication interface (CAN I / F) (134'), and a motor driver (Motor Driver) (135').

[0037] The above sensor (131') detects the detection signal of the handwheel sensor (110') and the motor current signal or motor rotation speed (RPM) signal detected from the electric steering motor (120').

[0038] The above MCU (132') outputs a motor current control signal applied to the electric steering motor (120') based on the pre-classified handwheel torque value and motor current value for steering angle control according to the above-mentioned vehicle speed range.

[0039] The above power connector (133') receives driving power (VCC) from the vehicle's battery.

[0040] The above CAN communication interface (134') receives a vehicle speed signal required for steering control through vehicle CAN (Controller Area Network) communication.

[0041] The above motor driver (135') is configured to include a motor driving element, such as an FET (field effect transistor), which converts electricity supplied from the vehicle's battery into a low-voltage / high-current driving signal and outputs it according to a motor current control signal input from the MCU (132'), and is mounted on a circuit board constituting the steering controller (130').

[0042] The above immersion tank (110) immerses the motor driver mounted on the circuit board constituting the steering controller (130').

[0043] The above cooling tank (120) stores liquid immersion refrigerant.

[0044] The above-mentioned immersion refrigerant circulation pump (130) supplies the immersion refrigerant contained in the cooling tank (120) to the immersion tank (110) and then circulates it so that it is discharged from the immersion tank (110).

[0045] The above circulation pump controller (140) operates the immersion refrigerant circulation pump (130) to circulate the immersion refrigerant, and compares the electric steering motor driving value converted using the handwheel torque detected from the handwheel sensor (110') or the electric steering motor driving value converted using the driving signal applied to the electric steering motor (120') with predetermined motor heat generation values. If it is determined that the electric steering motor driving value exceeds the motor heat generation threshold value, the circulation pump controller (140) operates the immersion refrigerant circulation pump (130) to circulate the refrigerant, thereby bringing the immersion refrigerant into direct contact with the motor driving element (e.g., FET) of the motor driver immersed in the immersion tank (110) to perform heat dissipation for the motor driving element (e.g., FET).

[0046] The above circulation pump controller (140) may be mounted on a circuit board that constitutes the steering controller (130') as a steering control ECU, or may be mounted on an independent circuit board different from the circuit board that constitutes the steering control ECU.

[0047] The liquid immersion cooling device (100) for a vehicle electric steering device according to the present invention, configured as described above, operates as follows.

[0048] In the vehicle electric steering device (100') in which the liquid immersion cooling device (100) for the vehicle electric steering device according to the present invention is used, when the steering controller (130') outputs a driving signal for controlling the motor current as described above, the electric steering motor (120') is driven to generate an assist force for rotating the handwheel (111'), and the vehicle wheels can be easily steered according to the driver's will by the assist force thus generated.

[0049] Meanwhile, when the motor driver (135') converts the electricity supplied from the vehicle's battery into a low-voltage / high-current driving signal and outputs it according to the motor current control signal input of the MCU (132') and the electric steering motor (120') is driven, the motor driving element (e.g., FET) mounted on the circuit board constituting the steering controller (130') overheats.

[0050] Accordingly, the circulation pump controller (140) drives the immersion refrigerant circulation pump (130) to circulate the refrigerant by performing control operations as shown in (a), (b), and (c) of FIG. 3 in order to perform heat dissipation for the motor driving element (e.g., FET).

[0051] (Example 1)

[0052] Embodiment 1 is an embodiment in which the circulation pump controller (140) drives the immersion refrigerant circulation pump (130) to circulate the refrigerant by the control operation shown in (a) of FIG. 3, thereby bringing the immersion refrigerant into direct contact with the motor drive element (e.g., FET) of the motor driver (135') immersed in the immersion tank (110) to perform heat dissipation for the motor drive element (e.g., FET).

[0053] The above circulation pump controller (140) compares the electric steering motor drive value converted using the handwheel torque detected from the handwheel sensor (110') and the electric steering motor drive value converted using the drive signal applied to the electric steering motor (120') with predetermined motor heat generation values, and if it is determined that the electric steering motor drive value exceeds the motor heat generation threshold value, the above circulation pump controller (140) drives the immersion refrigerant circulation pump (130) to circulate the refrigerant.

[0054] Example 1 is an example that uses both the electric steering motor drive value converted using the above-mentioned handwheel torque and the electric steering motor drive value converted using the drive signal applied to the above-mentioned electric steering motor (120').

[0055] (Example 2)

[0056] Embodiment 2 is an embodiment in which the circulation pump controller (140) drives the immersion refrigerant circulation pump (130) to circulate the refrigerant by the control operation shown in (b) of FIG. 3, thereby bringing the immersion refrigerant into direct contact with the motor drive element (e.g., FET) of the motor driver (135') immersed in the immersion tank (110) to perform heat dissipation for the motor drive element (e.g., FET).

[0057] The above circulation pump controller (140) compares only the electric steering motor drive value converted using the handwheel torque detected from the handwheel sensor (110') with the predetermined motor heat generation values, and if it is determined that the electric steering motor drive value exceeds the motor heat generation threshold value, it drives the liquid immersion refrigerant circulation pump (130) to circulate the refrigerant.

[0058] Example 2 is an example that uses only the electric steering motor drive value converted using the above-mentioned handwheel torque.

[0059] (Example 3)

[0060] Embodiment 3 is an embodiment in which the circulation pump controller (140) drives the immersion refrigerant circulation pump (130) to circulate the refrigerant by the control operation shown in (c) of FIG. 3, thereby bringing the immersion refrigerant into direct contact with the motor drive element (e.g., FET) of the motor driver (135') immersed in the immersion tank (110) to perform heat dissipation for the motor drive element (e.g., FET).

[0061] The above circulation pump controller (140) uses the drive signal applied to the electric steering motor (120') to convert the electric steering motor drive value into a value corresponding to predetermined motor heat generation values, and when it is determined that the electric steering motor drive value exceeds the motor heat generation threshold value, it drives the liquid immersion refrigerant circulation pump (130) to circulate the refrigerant.

[0062] Example 3 is an example that uses only the electric steering motor drive value converted using the drive signal applied to the electric steering motor (120'). In this case, the circulation pump controller (140) measures the PWM signal pulse width of the drive signal applied to the electric steering motor (120') and converts the electric steering motor drive value.

[0063] When converting the electric steering motor driving value by measuring the PWM signal pulse width of the driving signal applied to the electric steering motor (120') as described above, the electric steering motor driving value is determined according to the width of the pulse width, which is proportional to the amount of current applied to the electric steering motor (120') and also proportional to the heat generation value of the electric steering motor (120').

[0064] Figure 4 is a graph explaining the control operation of the circulation pump controller (140) shown in (c) of Figure 3.

[0065] If, as shown in (a) of Fig. 4, the motor heating threshold value is 50, and the electric steering motor driving value converted by measuring the PWM signal pulse width of the driving signal applied to the electric steering motor (120') is 10, the circulation pump controller (140) does not drive the liquid immersion refrigerant circulation pump (130).

[0066] This case corresponds to a state in which the motor driving element (e.g., FET) of the above motor driver (135') is not overheated.

[0067] In contrast, if, as shown in (b) of FIG. 4, the motor heat generation threshold value is 50 and the electric steering motor drive value converted by measuring the PWM signal pulse width of the drive signal applied to the electric steering motor (120') is 55, the circulation pump controller (140) drives the immersion refrigerant circulation pump (130) to directly contact the motor drive element (e.g., FET) of the motor driver (135') with the immersion refrigerant to perform heat dissipation for the motor drive element (e.g., FET).

[0068] This case corresponds to a state in which the motor driving element (e.g., FET) of the above motor driver (135') is overheated to a level similar to the motor heating threshold.

[0069] In contrast, if, as shown in (c) of FIG. 4, the motor heat generation threshold value is 50 and the electric steering motor drive value converted by measuring the PWM signal pulse width of the drive signal applied to the electric steering motor (120') is 90, the circulation pump controller (140) drives the immersion refrigerant circulation pump (130) to directly contact the motor drive element (e.g., FET) of the motor driver (135') with the immersion refrigerant to perform heat dissipation for the motor drive element (e.g., FET).

[0070] In this case, the motor driving element (e.g., FET) of the motor driver (135') is overheated to a level significantly higher than the motor heat generation threshold, and it is preferable to circulate the immersion refrigerant for a relatively longer period of time compared to the case of (b) of Fig. 4.

[0071] As can be seen from the above, according to the present invention, heat dissipation for the motor driving element (e.g., FET) of the motor driver (135') is performed by directly contacting the liquid immersion refrigerant with the motor driving element (e.g., FET), so that significantly improved heat dissipation performance can be expected compared to air cooling heat dissipation technology using a conventional heating plate or indirect liquid cooling heat dissipation technology using a conventional heat pipe.

Claims

1. A handwheel sensor (110') configured as a TOS (Torque Only Sensor) that detects only handwheel torque when the steering angle of the handwheel (111') is adjusted by the driver, or a TAS (Torque and Angle Sensor) that detects both the steering angle and the handwheel torque; and an electric steering motor (120') that generates an assist force to rotate the handwheel (111') by being driven by a driving signal that controls the motor current; And a steering controller (130') configured to output a driving signal for controlling the motor current applied to the electric steering motor based on the handwheel torque value and motor current value classified in advance for steering angle control according to the vehicle speed range when inputting the vehicle speed signal and the handwheel torque or both the steering angle and handwheel torque detected by the handwheel sensor (110') and the motor current signal or the motor rotation speed (RPM) signal detected from the electric steering motor (120'), A vehicle electric steering device characterized in that a motor driver mounted on a circuit board constituting the steering controller (130') is immersed in an immersion tank (110) and an immersion refrigerant contained in a cooling tank (120) is circulated by operating an immersion refrigerant circulation pump (130), and the electric steering motor driving value converted using the handwheel torque detected from the handwheel sensor (110') and the electric steering motor driving value converted using the driving signal applied to the electric steering motor (120') are compared with predetermined motor heat generation values, and when it is determined that the electric steering motor driving value exceeds a motor heat generation threshold value, the circulation pump controller (140) drives the immersion refrigerant circulation pump (130) to circulate the refrigerant, thereby bringing the immersion refrigerant directly into contact with the motor driving element of the corresponding motor driver immersed in the immersion tank (110) to perform heat dissipation for the corresponding motor driving element. Liquid immersion cooling device.

2. A liquid immersion cooling device for a vehicle electric steering device, characterized in that in the first paragraph, the circulation pump controller (140) compares only the electric steering motor drive value converted using the handwheel torque detected from the handwheel sensor (110') with predetermined motor heat generation values ​​and drives the liquid immersion coolant circulation pump (130) to circulate the coolant when it is determined that the electric steering motor drive value exceeds the motor heat generation threshold value.

3. A liquid immersion cooling device for a vehicle electric steering device, characterized in that in the first paragraph, the circulation pump controller (140) compares only the electric steering motor drive value converted using the drive signal applied to the electric steering motor (120') with predetermined motor heat generation values, and drives the liquid immersion refrigerant circulation pump (130) to circulate the refrigerant when it is determined that the electric steering motor drive value exceeds the motor heat generation threshold value.

4. A liquid immersion cooling device for a vehicle electric steering device, characterized in that in the third paragraph, the circulation pump controller (140) measures the PWM signal pulse width of the driving signal applied to the electric steering motor (120') and converts the electric steering motor driving value.

5. A liquid immersion cooling device for a vehicle electric steering device, characterized in that in the first paragraph, the circulation pump controller (140) is mounted on a circuit board that constitutes the steering controller (130') as an ECU (Electronic Control Unit) for steering control.

6. A liquid immersion cooling device for a vehicle electric steering device, characterized in that in the first paragraph, the circulation pump controller (140) is mounted on an independent circuit board different from the circuit board that constitutes the steering controller (130') as an ECU (Electronic Control Unit) for steering control.

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