Control device for water pump motor and control method for water pump motor

Abstract

The present application provides a kind of control device of water pump motor, which can reduce power consumption without always driving with the duty cycle of vehicle driving motor lock assumption. Control device carries out the following processing: set the target second duty cycle of vehicle driving motor lock assumption case;Set the first specified time of the circulation amount of cooling water changes until the target first duty cycle transitions to target second duty cycle, and the second specified time of the duty cycle transition from target first duty cycle to target second duty cycle is executed;According to the current vehicle driving motor speed and torque, in the case where vehicle driving motor is in the state of locking, the fastest time required for locking is calculated;And in the case where the fastest time is less than the sum of the first specified time and the second specified time, the target duty cycle is set as the target second duty cycle.

Description

Technical Field

[0001] This invention relates to a control device and method for controlling the power supply to a pump motor of a water pump in a three-phase inverter that cools the cooling water circuit of a vehicle drive motor by changing the duty cycle. Background Technology

[0002] The vehicle is equipped with a vehicle drive motor. This vehicle drive motor is driven, for example, by a three-phase inverter. The three-phase inverter is cooled by cooling water circulating in a cooling water circuit. In the cooling water circuit, cooling water is circulated by a water pump. The pump output is adjusted according to the rotational speed of the pump motor that drives the pump. The rotational speed of the pump motor is proportional to the supplied power. The power supplied to the pump motor is controlled by changing the duty cycle (e.g., Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2023-107447 Summary of the Invention In vehicles, the vehicle drive motor may sometimes lock up, causing the three-phase current in the three-phase inverter to concentrate on a specific phase (phase concentration), increasing the heat generated by the three-phase inverter. When the vehicle drive motor lockup or phase concentration of the three-phase inverter is detected and the cooling water volume is increased, the heat generated by the three-phase inverter may not be adequately addressed in time due to factors such as the transition time of the duty cycle and the time difference between the increase in the duty cycle and the increase in the cooling water volume.

[0004] Therefore, a duty cycle is set in the cooling water circuit assuming the vehicle drive motor is locked. In other words, when the vehicle drive motor is not locked, more than the necessary amount of cooling water is used, consuming a corresponding amount of electricity.

[0005] Therefore, the object of the present invention is to provide a control device and control method for a water pump motor, wherein the control device does not need to always drive at a duty cycle that is assumed to be locked for a vehicle drive motor, thereby reducing power consumption.

[0006] The water pump motor control device of the present invention controls the power supply to the pump motor of the water pump that cools the cooling water circuit of the three-phase inverter driving the vehicle drive motor by changing the duty cycle. The water pump motor control device performs the following processing: setting a target first duty cycle assuming the vehicle drive motor is unlocked and a target second duty cycle assuming the vehicle drive motor is locked; setting a first predetermined time until the cooling water circulation changes when transitioning from the target first duty cycle to the target second duty cycle and a second predetermined time until the duty cycle transitions from the target first duty cycle to the target second duty cycle; calculating the fastest time required until the vehicle drive motor is locked, based on the current command torque and speed of the vehicle drive motor; and setting the target duty cycle to the target second duty cycle if the fastest time is less than the sum of the first predetermined time and the second predetermined time.

[0007] The water pump motor control method of the present invention controls the power supply to the pump motor of the water pump that cools the cooling water circuit of the three-phase inverter driving the vehicle drive motor by changing the duty cycle. The water pump motor control method includes the following steps: setting a target first duty cycle assuming the vehicle drive motor is unlocked and a target second duty cycle assuming the vehicle drive motor is locked; setting a first predetermined time until the cooling water circulation changes when transitioning from the target first duty cycle to the target second duty cycle and a second predetermined time until the duty cycle transitions from the target first duty cycle to the target second duty cycle; calculating the fastest time required until the vehicle drive motor is locked, based on the current command torque and speed of the vehicle drive motor; and setting the target duty cycle to the target second duty cycle if the fastest time is less than the sum of the first predetermined time and the second predetermined time.

[0008] Invention Effects According to the control device and control method for the water pump motor of the present invention, it is not necessary to always drive with the duty cycle of the vehicle drive motor that is assumed to be locked, thereby reducing power consumption. Attached Figure Description

[0009] Figure 1 This is a schematic diagram illustrating a vehicle drive motor according to the embodiment.

[0010] Figure 2 It is a chart representing the target duty cycle.

[0011] Figure 3 This is a block diagram showing a control device as an example of an implementation method.

[0012] Figure 4 It is a chart representing the fastest time mapping table.

[0013] Figure 5 It is a chart illustrating the first specified time.

[0014] Figure 6 It is a chart illustrating the second specified time.

[0015] Figure 7 This is a flowchart illustrating the process of controlling the change of the target duty cycle as an example of an implementation method. Detailed Implementation

[0016] Hereinafter, an example of an embodiment of the present invention will be described in detail. In the following description, the specific shapes, materials, orientations, values, etc., are examples for the purpose of understanding the present invention and can be appropriately changed according to the use, purpose, specifications, etc.

[0017] [Vehicle drive motor] use Figure 1 The vehicle drive motor 10 according to the embodiment will be described.

[0018] The vehicle drive motor 10 is, for example, a three-phase AC motor used in driving electric vehicles (BEVs). However, the vehicle drive motor of the present invention is not limited to a motor used in electric vehicles. The vehicle drive motor of the present invention is a motor generator, and the vehicle in this embodiment can be a hybrid electric vehicle (HEV) or a plug-in hybrid electric vehicle (PHEV). Furthermore, the rotational speed of the vehicle drive motor 10 is detected by a speed sensor 16 provided on the vehicle drive motor 10.

[0019] The vehicle drive motor 10 is powered from the battery 12 via a three-phase inverter 11. The three-phase inverter 11 has functions such as converting the direct current supplied from the battery 12 into alternating current that can be used by the vehicle drive motor 10, and controlling the frequency of the alternating current to adjust the speed or torque of the vehicle drive motor 10. The three-phase inverter 11 can be installed in the power control unit.

[0020] The three-phase inverter 11 is cooled by cooling water in the cooling water circuit 13. Cooling water in the cooling water circuit 13 is circulated by a drive water pump 14. Furthermore, the cooling water volume (cooling water circulation volume) in the cooling water circuit 13 is adjusted according to the output of the water pump 14. The output of the water pump 14 is proportional to the rotational speed of the pump motor 15 that drives the water pump 14. Additionally, a cooling water temperature sensor 17 for detecting the cooling water temperature is installed in the cooling water circuit 13.

[0021] The rotational speed of the pump motor 15 is controlled by an electronic control unit (ECU) 20, which serves as the control device. The ECU 20 controls the electrical power supplied to the pump motor 15 by changing its duty cycle, thereby controlling the rotational speed of the pump motor 15. Details about the ECU 20 will be described later.

[0022] [Control Device] use Figures 2 to 6 The ECU20, which is one example of an implementation method, will be described.

[0023] As described above, ECU 20 controls the power supply to the pump motor 15 by changing the duty cycle. Details regarding the control device 20 will be described later, but it reduces power consumption by eliminating the need to always operate at a locked duty cycle assuming the vehicle drive motor 10 is locked.

[0024] Here, locking of the vehicle drive motor 10 refers to a state in which the vehicle drive motor 10 continuously applies torque at zero rotation. Locking of the vehicle drive motor 10 occurs, for example, when the accelerator pedal is held while the vehicle is driving on a slope, or when the accelerator and brake are pressed simultaneously.

[0025] The control unit 20 has a central processing unit (CPU) as an arithmetic processing unit and storage units such as random access memory (RAM) and read-only memory (ROM). It utilizes the temporary storage function of RAM and performs signal processing according to the program pre-stored in ROM. The ECU 20 can be connected to other ECUs in the vehicle.

[0026] like Figure 2 As shown, the control device 20 sets a target first duty cycle assuming the vehicle drive motor 10 is unlocked and a target second duty cycle assuming the vehicle drive motor 10 is locked; details will be described later. Furthermore, the target first and target second duty cycles are set differently based on the coolant temperature. Both the target first and target second duty cycles are set to a higher value as the coolant temperature increases.

[0027] like Figure 3As shown, the control device 20 includes a command torque acquisition unit 21, a speed acquisition unit 22, a fastest time calculation unit 23, a determination unit 24, a target duty cycle determination unit 25, and an execution duty cycle determination unit 26. The command torque acquisition unit 21, speed acquisition unit 22, fastest time calculation unit 23, determination unit 24, target duty cycle determination unit 25, and execution duty cycle determination unit 26 are implemented by the CPU executing a program stored in ROM or RAM.

[0028] The command torque acquisition unit 21 acquires the command torque for the vehicle drive motor 10. The command torque acquisition unit 21 can acquire the command torque from the driving ECU (not shown) that controls the vehicle drive motor 10.

[0029] The speed acquisition unit 22 acquires the speed of the vehicle drive motor 10. The speed acquisition unit 22 can acquire the speed of the vehicle drive motor 10 from the speed sensor 16, which is installed on the vehicle drive motor 10 and connected to the ECU.

[0030] The fastest time calculation unit 23 calculates the fastest time τ required for the vehicle drive motor 10 to lock up when it locks, based on the command torque obtained by the command torque acquisition unit 21, the speed obtained by the speed acquisition unit 22, and the fastest time mapping table M1 (details to be described later). lock "The fastest time τ required for locking when the vehicle drive motor 10 is locked." lock "This indicates the fastest time required for the vehicle drive motor 10 to lock up when the vehicle drive motor 10 is locked, based on the combination of the command torque of the vehicle drive motor 10 and the current speed of the vehicle drive motor 10 in the fastest time mapping table M1."

[0031] like Figure 4 As shown, the fastest time mapping table M1 represents the command torque of the vehicle drive motor 10, the current speed of the vehicle drive motor 10, and the fastest time τ required for the vehicle drive motor 10 to lock when locked. lock The fastest time mapping table M1 is pre-stored in the storage unit. The fastest time mapping table M1 can have different characteristics depending on the model of the vehicle drive motor 10 or the vehicle it is mounted on. The fastest time mapping table M1 can be created based on experimental data and actual test data of the vehicle.

[0032] The determination unit 24 determines the fastest time τ calculated by the fastest time calculation unit 23. lock Whether each is less than the first specified time τ described later in the details flow With the second specified time τ trans sum.

[0033] like Figure 5 As shown, the first specified time τ flowThis represents the time difference between the moment when the duty cycle of the electrical power supplied to the pump motor 15 increases and the moment when the cooling water volume in the cooling water circuit 13 actually increases. The first specified time τ flow The time difference is mainly due to factors such as the piping length of cooling water circuit 13. The first specified time τ flow Pre-stored in the storage unit. First specified time τ flow It can vary depending on the type of cooling water circuit 13.

[0034] like Figure 6 As shown, when changing the duty cycle from, for example, 50% to 80%, the speed of pump 14 needs to be increased slowly, therefore the duty cycle needs to be changed slowly. The second specified time τ trans It refers to the transition time during which the duty cycle is slowly changed from the first target duty cycle to the second target duty cycle when the target duty cycle is changed from the first target duty cycle to the second target duty cycle.

[0035] The target duty cycle determination unit 25 has the fastest time τ in the decision unit 24. lock Greater than the first specified time τ flow With the second specified time τ trans In the case of the sum of these, the target duty cycle is set as the first target duty cycle. Furthermore, in the decision unit 24, the fastest time τ... lock Less than the first specified time τ flow With the second specified time τ trans In the case of the sum of the two, the target duty cycle determination unit 25 sets the target duty cycle as the target second duty cycle.

[0036] The duty cycle determination unit 26 acquires the current duty cycle and calculates the execution duty cycle based on the current duty cycle and the target duty cycle. The execution duty cycle determination unit 26 can calculate the execution duty cycle as shown in Equation 1.

[0037] [Formula 1]

[0038] Furthermore, the duty cycle determination unit 26 can calculate the duty cycle using the moving average method.

[0039] By configuring the structure described above, the fastest time required until locking occurs when the vehicle drive motor 10 locks is shorter than the first predetermined time τ. flow With the second specified time τ trans In the case of the sum, by changing the duty cycle, it is not necessary to set it to a duty cycle that is always locked. As a result, power consumption can be reduced.

[0040] [Control of target duty cycle changes] use Figure 7The process for controlling the change of target duty cycle, as an example of an implementation method, will be explained.

[0041] The target duty cycle change control is based on the operation of the ECU 20 described above. The following steps are performed by various parts of the ECU 20. In step S11, the command torque acquisition unit 21 acquires the command torque for the vehicle drive motor 10. In step S12, the speed acquisition unit 22 acquires the speed of the vehicle drive motor 10.

[0042] In step S13, the fastest time calculation unit 23 calculates the fastest time τ required for the vehicle drive motor 10 to lock when it locks, based on the command torque obtained by the command torque acquisition unit 21, the speed obtained by the speed acquisition unit 22, and the fastest time mapping table M1. lock .

[0043] In step S14, the determination unit 24 determines the fastest time τ calculated by the fastest time calculation unit 23. lock Is it the first specified time τ? flow With the second specified time τ trans The sum of the above. In step S14, if "yes", proceed to step S15. In step S15, if "no", proceed to step S16.

[0044] In step S15, the target duty cycle determination unit 25 sets the target duty cycle as the target second duty cycle. In step S16, the target duty cycle determination unit 25 sets the target duty cycle as the target second duty cycle. In step S17, the duty cycle determination unit 26 acquires the current duty cycle and calculates the execution duty cycle based on the current duty cycle and the target duty cycle.

[0045] Furthermore, the present invention is not limited to the above-described embodiments and their variations, and various changes or improvements can be made within the scope of the matters described in the patent application of this application.

[0046] Symbol Explanation 10-Vehicle drive motor, 11-Three-phase inverter, 12-Battery, 13-Cooling water circuit, 14-Water pump, 15-Pump motor, 16-Speed ​​sensor, 17-Cooling water temperature sensor, 20-ECU (Control Unit), 21-Command torque acquisition unit, 22-Speed ​​acquisition unit, 23-Fastest time calculation unit, 24-Decision unit, 25-Target duty cycle determination unit, 26-Execution duty cycle determination unit, M1-Fastest time mapping table, τ lock -Fastest time, τ flow -Fastest time, τ trans - Fastest time.

Claims

1. A control device for a water pump motor, which controls the power supply to a pump motor of a water pump that cools the cooling water circuit of a three-phase inverter used to drive a vehicle drive motor by changing the duty cycle, characterized in that the control device for the water pump motor performs the following processing: Set a target first duty cycle assuming the vehicle drive motor is unlocked and a target second duty cycle assuming the vehicle drive motor is locked; The first predetermined time is set until the cooling water circulation volume changes when transitioning from the target first duty cycle to the target second duty cycle, and the second predetermined time is set until the duty cycle transitions from the target first duty cycle to the target second duty cycle. Based on the commanded torque and speed of the vehicle drive motor, and assuming the vehicle drive motor is locked, calculate the fastest time required to lock. and If the fastest time is less than the sum of the first specified time and the second specified time, the target duty cycle is set as the target second duty cycle.

2. A control method for a water pump motor, which controls the power supply to the pump motor of a water pump that cools the cooling water circuit of a three-phase inverter used to drive a vehicle drive motor by changing the duty cycle, the control method for the water pump motor being characterized by comprising the following steps: Set a target first duty cycle assuming the vehicle drive motor is unlocked and a target second duty cycle assuming the vehicle drive motor is locked; The first predetermined time is set until the cooling water circulation volume changes when transitioning from the target first duty cycle to the target second duty cycle, and the second predetermined time is set until the duty cycle transitions from the target first duty cycle to the target second duty cycle. Based on the commanded torque and speed of the vehicle drive motor, and assuming the vehicle drive motor is locked, calculate the fastest time required to lock. and If the fastest time is less than the sum of the first specified time and the second specified time, the target duty cycle is set as the target second duty cycle.

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