JP2006258076A - Electric liquid pump, its control method and control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent heating to a rated value or more in a control device for driving an electric liquid pump even if foreign matter bites in. <P>SOLUTION: This invention executes a step (A3) of detecting a rotating speed of an electric motor, and a step (A4 to A8) of performing one or more times of processing for rotating the electric motor for a predetermined time after stopping the electric motor for the predetermined time when the detected rotating speed of the electric motor becomes a predetermined rotating speed or less. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electric liquid pump that supplies liquid of a necessary hydraulic pressure to a hydraulic circuit from a liquid pump driven by an electric motor, and a control method and control apparatus therefor.

  Conventionally, a compact and compact electric hydraulic pump that drives the hydraulic pump with an electric motor is used to operate the hydraulic pressure required for the clutch of an automatic transmission when, for example, the engine is idling stopped while the automobile is stopped. It is used to supply oil or it is used to supply the required hydraulic oil to the cooling jacket of the electric motor of the hybrid vehicle.

  The electric liquid pump has a smaller torque than a mechanical hydraulic pump driven by a large torque engine such as an engine, so that foreign matter such as chips generated during manufacturing or sliding during operation is caught. In some cases, foreign materials that can be crushed by the mechanical hydraulic pump are also caught, and as a result, the rotational speed of the electric liquid pump is reduced and stopped. Therefore, a control method and device for an electric liquid pump that switches the rotation direction of the electric liquid pump or restarts it with a large torque in order to reliably and accurately handle the entry of foreign matter has been disclosed (patent) Reference 1).

JP 2004-353624 A

  However, in the conventional control method and apparatus for the electric liquid pump, the rotation direction of the electric liquid pump is switched or restarted with a large torque in order to deal with foreign matter biting. There is a possibility that the temperature of electronic components (FET circuit, motor drive IC, etc.) in the controller to be driven rises above the rated value (upper limit temperature).

  An object of the present invention is to prevent a control device that drives an electric liquid pump from generating heat beyond a rated value even when foreign matter is caught.

  According to a first aspect of the present invention, in a method for controlling an electric liquid pump that supplies liquid of a necessary hydraulic pressure to a hydraulic circuit from a liquid pump driven by an electric motor, the first method of detecting the number of revolutions of the electric motor is provided. And when the detected number of rotations of the electric motor is equal to or less than a predetermined number of rotations, the electric motor is stopped for a predetermined time and then the electric motor is rotated at least once for a predetermined time. And a second step.

  According to a second aspect of the present invention, in a method for controlling an electric liquid pump that supplies a liquid having a required hydraulic pressure to a hydraulic circuit from a liquid pump driven by an electric motor, the first method of detecting the rotational speed of the electric motor is provided. And when the detected number of rotations of the electric motor becomes equal to or less than a predetermined number of rotations, the process of rotating the electric motor in the positive direction for a predetermined time after stopping the electric motor for a predetermined time is 1 If the electric motor does not rotate even after the second step performed more than once and the second step, the electric motor is stopped for a predetermined time, and then the electric motor is rotated in the reverse direction for a predetermined time. And a third step of performing the process of stopping the electric motor for a predetermined time and rotating it again in the positive direction for a predetermined time once or more.

  According to a third aspect of the present invention, in a control method for an electric liquid pump that supplies liquid of a necessary hydraulic pressure to a hydraulic circuit from a liquid pump driven by an electric motor, the first method of detecting the number of revolutions of the electric motor is provided. And when the detected number of rotations of the electric motor is equal to or less than a predetermined number of rotations, the electric motor is stopped for a predetermined time, and then the electric motor is rotated in the reverse direction for a predetermined time. And a second step of performing the process of stopping the electric motor for a predetermined time and rotating the electric motor in the positive direction for a predetermined time at least once.

  In a fourth aspect of the present invention, in a control device for an electric liquid pump that supplies liquid of a necessary hydraulic pressure to a hydraulic circuit from a liquid pump driven by an electric motor, the rotation speed for detecting the rotation speed of the electric motor. And a process of rotating the electric motor for a predetermined time after stopping the electric motor for a predetermined time when the rotation speed of the electric motor detected by the detection unit and the rotation speed detection unit is equal to or lower than a predetermined rotation speed. And a rotation control unit that performs at least once.

  In a fifth aspect of the present invention, in a control device for an electric liquid pump that supplies liquid of a necessary hydraulic pressure to a hydraulic circuit from a liquid pump driven by an electric motor, the number of revolutions for detecting the number of revolutions of the electric motor. When the number of rotations of the electric motor detected by the detection unit and the number of rotations detection unit is equal to or less than a predetermined number of rotations, the electric motor is stopped for a predetermined time, and then the electric motor is moved in the positive direction for a predetermined time. If the electric motor does not rotate even if the electric motor does not rotate, the electric motor is stopped for a predetermined time, and then the electric motor is rotated in the reverse direction for a predetermined time. And a rotation control unit that performs the process of stopping for a time and rotating again in the positive direction for a predetermined time once or more.

  In a sixth aspect of the present invention, in a control device for an electric liquid pump that supplies liquid of a necessary hydraulic pressure from a liquid pump driven by an electric motor to a hydraulic circuit, the number of revolutions for detecting the number of revolutions of the electric motor. When the number of rotations of the electric motor detected by the detection unit and the number of rotations detection unit is equal to or less than a predetermined number of rotations, the electric motor is stopped for a predetermined time, and then the electric motor is moved in the reverse direction for a predetermined time. And a rotation control unit that performs at least one process of rotating and then stopping the electric motor for a predetermined time and rotating the electric motor in a positive direction for a predetermined time.

  According to the present invention (claims 1-6), the temperature of the electronic components in the control device can be prevented from exceeding the rated value (upper limit temperature), and the drive of the electric motor can be continued. As a result, it is possible to more reliably and accurately handle the foreign matter biting of the electric liquid pump while suppressing fluctuations in the electrical characteristics of the electronic components in the control device. In addition, since such an effect requires only a change of software, an increase in cost can be suppressed.

(Embodiment 1)
A method and apparatus for controlling an electric liquid pump according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram schematically showing the configuration of the control device for the electric liquid pump according to the first embodiment of the present invention.

  The electric liquid pump includes a hydraulic pump 1 and an electric motor 3, is connected to the hydraulic circuit 2 as a flow path, and is electrically connected to the battery 4 via the control device 20. The control device 20 includes an FET circuit 6, a motor drive IC 7, a motor drive circuit 5, a unit rotation angle detection circuit 8, a voltage detection circuit 9, a shunt resistor 10, a current detection circuit 11, a microcomputer 12, Have

  The hydraulic pump 1 supplies the necessary hydraulic pressure to the hydraulic circuit 2. The hydraulic pump 1 is rotationally driven by an electric motor 3. As the hydraulic pump 1, it is preferable to use a pump that exhibits a pump action when the tooth surface approaches the tooth surface, such as a trochoid pump or a gear pump. When these pumps rotate in the forward direction, foreign matter will be caught on the side where the tooth surface and the tooth surface are joined. If this is rotated in the opposite direction, both tooth surfaces sandwiching the foreign matter will be separated and foreign matter will be easily removed. Because it can.

  The hydraulic pressure circuit 2 is a circuit having a predetermined flow path resistance R while a liquid with a predetermined hydraulic pressure flows, and is connected to the hydraulic pressure pump 1 as a flow path. As the hydraulic circuit 2, for example, when the engine is idling stopped while the vehicle is stopped, it is necessary for a hydraulic circuit that supplies hydraulic oil necessary for the clutch of the automatic transmission, or a cooling jacket for an electric motor of a hybrid vehicle. A cooling circuit for supplying hydraulic cooling oil can be used.

  The electric motor 3 drives the hydraulic pump 1 to rotate. Examples of the electric motor 3 include a sensorless three-phase brushless DC motor. The voltage of the battery 4 is applied to the three wires of the electric motor 3 via the FET circuit 6. A unit rotation angle detection circuit 8 is electrically connected to the three wires of the electric motor 3.

  The motor drive circuit 5 is a circuit for driving the electric motor 3 and includes an FET circuit 6 and a motor drive IC 7.

  The FET circuit 6 sequentially applies a voltage between two of the three lines of the electric motor 3 based on the unit rotation angle signal from the motor drive IC 7 to drive the electric motor 3 to rotate by the unit rotation angle. Further, the FET circuit 6 performs duty control by turning on and off the voltage applied between the two lines based on the command voltage signal from the motor drive IC 7 and the DC power supply voltage from the voltage detection circuit 9. The average voltage applied to the electric motor 3 is controlled to the command voltage. Here, the unit rotation angle signal is a signal related to the unit rotation angle detected by the unit rotation angle detection circuit 8. The command voltage signal is a signal related to the voltage commanded from the CPU 13. Here, the unit rotation angle signal is a signal related to the unit rotation angle detected by the unit rotation angle detection circuit 8. The command voltage signal is a signal related to the voltage commanded from the CPU 13.

  The duty control of the FET circuit 6 is performed by the following steps. Referring to FIG. 3, first, a DC power supply voltage is acquired from the voltage detection circuit 9 (step B1). Next, the minimum output duty is calculated based on the acquired DC power supply voltage (step B2). Here, the minimum output duty is calculated by, for example, an arithmetic expression “(minimum motor voltage specified value; for example, 0.4) × 12 × (DC power supply voltage)”. Next, an output duty is calculated based on the command voltage signal (step B3). Here, the output duty is calculated based on the deviation of the command voltage signal. Next, it is determined whether or not the calculated output duty is equal to or less than the minimum output duty (step B4). When the output duty is larger than the minimum output duty (NO in step B4), the process proceeds to step B6. If the output duty is less than or equal to the minimum output duty (YES in step B4), the output duty is corrected to the minimum output duty (step B5). If the output duty is larger than the minimum output duty (NO in step B4), the calculated output duty is used as it is, and the voltage applied between the two lines is turned on and off to control the duty (step B6). On the other hand, when the output duty is corrected to the minimum output duty (step B5), the voltage applied between the two lines is turned on and off using the minimum output duty to control the duty (step B6).

  The motor drive IC 7 sends the unit rotation angle signal from the unit rotation angle detection circuit 8 to the FET circuit 6 and the input / output circuit 16. The motor drive IC 7 sends a command voltage signal from the input / output circuit 16 to the FET circuit 6.

  The unit rotation angle detection circuit 8 detects the unit rotation angle of the electric motor 3 by sequentially detecting the low voltage line among the three wires circulating as the electric motor 3 rotates, and sends the unit rotation angle signal to the motor drive IC 7. To do. The unit rotation angle signal is used for motor drive control by the motor drive circuit 5 and is sent to the microcomputer 12 via the motor drive IC 7.

  The voltage detection circuit 9 detects the DC power supply voltage of the battery 4 and sends a DC power supply voltage signal to the FET circuit 6.

  The shunt resistor 10 has one end connected to the first wiring connecting the FET circuit 6 and the current detection circuit 11, and the other end connected to the second wiring connecting the FET circuit 6 and the battery 4 to the current detection circuit 11. .

  The current detection circuit 11 measures the voltage between both terminals of the shunt resistor 10, detects the motor current supplied to the electric motor 3, and sends a motor current signal to the microcomputer 12.

  The microcomputer 12 is a computer that performs control processing based on a predetermined program. The microcomputer 12 includes a CPU 13, a ROM 14, a RAM 15, and an input / output circuit 16.

  The CPU 13 performs various calculation processes based on the motor rotation number calculation program 17, the motor control program 18, and the current control program 19. The ROM 14 stores various programs executed by the CPU 13. The RAM 15 reads and writes data necessary for the CPU 13 during arithmetic processing.

  The input / output circuit 16 sends a unit rotation angle signal from the motor drive IC 7 to the CPU 13. The input / output circuit 16 sends the motor current signal from the current detection circuit 11 to the CPU 13. The input / output circuit 16 sends a command voltage signal from the CPU 13 to the motor drive IC 7.

  The ROM 14 stores programs such as a motor rotation number calculation program 17, a motor control program 18, a current control program 19 and the like, and predetermined information.

  The motor rotation number calculation program 17 is a program for calculating the motor rotation number of the electric motor 3 by counting unit rotation angle detection signals sent within a predetermined time. The motor rotation number calculation program 17 necessary for detecting the motor rotation number of the electric motor 3 and a portion related thereto (including the unit rotation angle detection circuit 8 and the CPU 13) constitute a rotation number detection unit.

  The motor control program 18 estimates the liquid temperature based on the motor rotational speed calculated by the motor rotational speed calculation program 17 and the motor current value detected by the current detection circuit 11, and is necessary at the estimated liquid temperature. This is a program for calculating a target value of a motor current for securing a hydraulic pressure.

  The current control program 19 is a program for controlling the motor current value detected by the current detection circuit 11 to be the target value calculated by the motor control program 18. When the current control program 19 is executed, the difference between the motor current value and the target value is calculated, the command voltage applied to the electric motor 3 is calculated using proportional control and integral control, and this command voltage signal is output. A program (including the current control program 19) necessary for controlling the rotation direction and rotation time of the electric motor 3 and a portion related thereto (including the FET circuit 6 and the CPU 13) constitute a rotation control unit. .

  Next, the operation of the control device for the electric liquid pump according to the first embodiment will be described with reference to the drawings. FIG. 2 is a flowchart schematically showing the operation of the control device for the electric liquid pump according to the first embodiment of the present invention.

  First, in order to discharge the necessary hydraulic pressure from the hydraulic pump 1 and supply it to the hydraulic circuit 2, the microcomputer 12 drives the electric motor 3 with a predetermined current value to drive the motor 3. In addition, a predetermined process is repeatedly executed based on the motor speed calculation program 17, the motor control program 18, and the current control program 19, and the motor current value I is calculated by the current detection circuit 11 each time execution of the predetermined process is started. Detect (Step A1).

Next, the microcomputer 12 determines whether or not the motor current value I is predefined prescribed current value I ₁ or more (step A2). If the motor current value I is not specified current value _{I 1} or more (NO in step A2), the flow returns to step A1.

If motor current value I is specified current value I ₁ or more (YES in step A2), the microcomputer 12 detects the motor rotational speed R of the electric motor 3 on the basis of the unit rotation angle signal from the unit rotation angle detecting circuit 8 (Step A3).

Next, the microcomputer 12, in order to determine whether bitten the hydraulic pump 1 is foreign matter, it is determined whether the motor rotation speed R is predefined operating speed R ₁ or less (step A4 ). If motor speed R is greater than the regulation revolution speed R ₁ (NO at step A4), the microcomputer 12 determines that the hydraulic pump 1 is operating normally not bite foreign matter is once terminated. If the motor rotation speed R is equal to or less than the specified rotation speed R ₁ (YES in step A4), the microcomputer 12 determines that the hydraulic pump 1 is biting in a foreign object, and performs restart processing (steps A5 to A8). If it is executed but still does not start, rotation direction switching processing (steps A9 to A14) is executed.

  Here, the lock determination region in which it is determined in steps A1 to A4 that the hydraulic pump 1 is biting (locked) with a foreign object is, for example, as shown in FIG.

  In the restart process, first, the microcomputer 12 stops the electric motor 3 for a predetermined time (for example, 30 seconds) in order to cool the control device 20 that has generated heat due to the biting of a foreign object (step A5). That is, the control voltage is not output from the CPU 13 (command voltage = 0V), and the control device 20 is cooled.

  Next, the microcomputer 12 rotates (forward rotation) the electric motor 3 for a predetermined time (for example, 5 seconds) in the rotation direction before the stop in order to restart (step A6). Here, regarding the relationship between the stop time and the rotation time of the electric motor 3 in the restart process, the cooling rate of the control device 20 when the electric motor 3 stops and the heating of the control device 20 when the electric motor 3 rotates. For example, if the heating rate is 6 times the cooling rate, the stop time of the electric motor 3 can be 6 times the rotation time. The relationship between the stop time and the rotation time of the electric motor 3 is the same in the rotation direction switching process.

Next, the microcomputer 12, the foreign matter is crushed chewing by the restart process, or whether (whether or not the motor rotation speed R is stipulated rotational speed R ₁ below) was started forward rotation again removed, i.e. It is determined whether the restart is successful (step A7). If the restart is successful (YES in step A7), the process is temporarily terminated.

If the restart is not successful (NO in step A7), the microcomputer 12 counts the number of restarts in step A6 after starting the restart process, and the counted number of restarts is a predetermined number of times defined in advance. It is determined whether or not N _a (for example, 5 times) or more (step A8). If the number of restarts are not specified number of times _{N a} more (NO in step A8), the flow returns to step A5. If the number of restarts is prescribed number _{N a} more (YES in step A8), it will execute switching process of the rotation direction (step A9~A14).

  Although most foreign object bites are eliminated by the restart process, the following rotation direction switching process (steps A9 to A14) is executed in order to eliminate the foreign object bites that are still not eliminated.

  In the rotation direction switching process, first, the microcomputer 12 stops the electric motor 3 for a predetermined time (for example, 30 seconds) in order to cool the control device 20 that has generated heat by the restart process (step A9).

  Next, the microcomputer 12 rotates (reversely rotates) the electric motor 3 for a predetermined time (for example, 5 seconds) in the direction opposite to the rotation direction before stopping (step A10).

  Next, the microcomputer 12 stops the electric motor 3 for a predetermined time (for example, 30 seconds) in order to cool the control device 20 that has generated heat by the reverse rotation process (step A11).

  Next, the microcomputer 12 rotates (forward rotation) the electric motor 3 in a rotation direction before stopping for a predetermined time (for example, 5 seconds) (step A12).

Next, the microcomputer 12 determines whether or not the foreign object is bitten or removed by the rotation direction switching process and starts normal rotation again (whether the motor rotation speed R is equal to or less than the specified rotation speed R ₁ ). That is, it is determined whether or not the activation is successful (step A13). If the activation is successful (YES in step A13), the process is temporarily terminated.

If the activation is not successful (NO in step A13), the microcomputer 12 counts the number of reverse rotation executions in step A10 after starting the rotation direction switching process, and the counted number of reverse rotation executions is defined in advance. It is determined whether or not the specified number N _b (for example, 5 times) or more (step A14). If reverse rotation execution count is not specified number of times _{N b} or (NO in step A14), the flow returns to step A9.

If reverse rotation number of execution times is the specified number of times N _b more (YES in step A14), that is, when the biting of the foreign matter by the switching process of the direction of rotation is not resolved, the microcomputer 12 restarts the process, the rotational direction The switching process and the control process for the electric motor 3 are stopped, and a fail process for issuing a warning is executed (step A15).

  According to the first embodiment, the temperature of the electronic components (FET circuit 6, motor drive IC 7, etc.) in the control device 20 does not exceed the rated value (upper limit temperature) even in the restart process and the rotation direction switching process. (See FIG. 5), and driving of the electric motor 3 can be continued. As a result, it is possible to more reliably and accurately handle the foreign matter biting of the electric liquid pump while suppressing fluctuations in the electrical characteristics of the electronic components in the control device 20. In addition, since such an effect requires only a change of software, an increase in cost can be suppressed.

  In the first embodiment, when the foreign matter biting of the hydraulic pump 1 is detected, only the rotation direction switching process (steps A9 to A14) is executed without executing the restart process (steps A5 to A8). You may make it do. According to this, when the electric liquid pump bites foreign matter, the electric motor 3 is reversely rotated and then rotated forward again, so that the biting foreign matter can be removed.

  In the first embodiment, at least one restart process for restarting the electric motor 3 with a large torque is performed instead of the restart process (steps A5 to A8) or the rotation direction switching process (steps A9 to A14). It may be performed more than once. When the restart process is performed with a large torque, the control device is configured so that the rotation time of the electric motor 3 is shorter than that at the normal torque, or the stop time of the electric motor 3 is longer than that at the normal torque. What is necessary is just to make it the temperature of the electronic component in 20 not exceed a rated value (upper limit temperature). As a result, it is possible to more reliably and accurately handle the foreign matter biting of the electric liquid pump while suppressing fluctuations in the electrical characteristics of the electronic components in the control device 20.

  In the first embodiment, a sensorless three-phase brushless DC motor is used as the electric motor 3. However, the present invention is not limited to this, and a two-phase brushless DC motor, a direct current motor, or the like may be used. A rotation speed detection device for detecting the number and a current detection device for detecting the motor current may be added.

It is the block diagram which showed typically the structure of the control apparatus of the electric liquid pump which concerns on Embodiment 1 of this invention. It is the flowchart figure which showed typically the action | operation of the control apparatus of the electric liquid pump which concerns on Embodiment 1 of this invention. It is the flowchart figure which showed typically the operation | movement of duty control of the FET circuit in the control apparatus of the electric liquid pump which concerns on Embodiment 1 of this invention. It is the graph which showed typically the lock determination area | region determined with having locked with the microcomputer in the control apparatus of the electric liquid pump which concerns on Embodiment 1 of this invention. It is the graph which showed typically the time-dependent change of the temperature of the electronic component in the control apparatus of the electric liquid pump which concerns on Embodiment 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydraulic pump 2 Hydraulic circuit 3 Electric motor 4 Battery 5 Motor drive circuit 6 FET circuit 7 Motor drive IC
8 Unit rotation angle detection circuit 9 Voltage detection circuit 10 Shunt resistance 11 Current detection circuit 12 Microcomputer 13 CPU
14 ROM
15 RAM
16 I / O circuit 17 Motor rotation speed calculation program 18 Motor control program 19 Current control program 20 Controller

Claims (6)

In the control method of the electric liquid pump for supplying the liquid of the required hydraulic pressure from the liquid pump driven by the electric motor to the hydraulic circuit,
A first step of detecting the rotational speed of the electric motor;
A second step of performing the process of rotating the electric motor at least once for a predetermined time after stopping the electric motor for a predetermined time when the detected rotation speed of the electric motor becomes equal to or lower than the predetermined rotation speed; When,
An electric liquid pump control method comprising: In the control method of the electric liquid pump for supplying the liquid of the required hydraulic pressure from the liquid pump driven by the electric motor to the hydraulic circuit,
A first step of detecting the rotational speed of the electric motor;
When the detected number of rotations of the electric motor is equal to or less than a predetermined number of rotations, the electric motor is stopped for a predetermined time, and then the process of rotating the electric motor in the positive direction for a predetermined time is performed at least once. Two steps,
If the electric motor does not rotate even in the second step, the electric motor is stopped for a predetermined time, then the electric motor is rotated in the reverse direction for a predetermined time, and then the electric motor is stopped for a predetermined time. A third step of performing the process of rotating in the positive direction again for a predetermined time once or more;
An electric liquid pump control method comprising: In the control method of the electric liquid pump for supplying the liquid of the required hydraulic pressure from the liquid pump driven by the electric motor to the hydraulic circuit,
A first step of detecting the rotational speed of the electric motor;
When the detected rotation speed of the electric motor is equal to or less than a predetermined rotation speed, the electric motor is stopped for a predetermined time, and then the electric motor is rotated in the reverse direction for a predetermined time. A second step of performing the process of stopping for a predetermined time and rotating in the positive direction for a predetermined time at least once;
An electric liquid pump control method comprising: In a control device for an electric liquid pump that supplies liquid of a necessary hydraulic pressure from a liquid pump driven by an electric motor to a hydraulic circuit,
A rotational speed detector for detecting the rotational speed of the electric motor;
When the number of rotations of the electric motor detected by the number of rotations detection unit becomes equal to or less than a predetermined number of rotations, the process of rotating the electric motor for a predetermined time after stopping the electric motor for a predetermined time is performed once or more A rotation control unit to perform,
An electric liquid pump control apparatus comprising: In a control device for an electric liquid pump that supplies liquid of a necessary hydraulic pressure from a liquid pump driven by an electric motor to a hydraulic circuit,
A rotational speed detector for detecting the rotational speed of the electric motor;
A process of rotating the electric motor in a positive direction for a predetermined time after stopping the electric motor for a predetermined time when the rotation speed of the electric motor detected by the rotation speed detection unit is equal to or lower than a predetermined rotation speed; If the electric motor does not rotate at least once, after stopping the electric motor for a predetermined time, the electric motor is rotated in the reverse direction for a predetermined time, and then the electric motor is stopped for a predetermined time, A rotation control unit that performs the process of rotating in the positive direction again for a predetermined time once or more;
An electric liquid pump control apparatus comprising: In a control device for an electric liquid pump that supplies liquid of a necessary hydraulic pressure from a liquid pump driven by an electric motor to a hydraulic circuit,
A rotational speed detector for detecting the rotational speed of the electric motor;
When the rotation speed of the electric motor detected by the rotation speed detection unit is equal to or lower than a predetermined rotation speed, the electric motor is stopped for a predetermined time, and then the electric motor is rotated in the reverse direction for a predetermined time. A rotation control unit that performs the process of stopping the electric motor for a predetermined time and rotating the electric motor in the positive direction for a predetermined time at least once;
An electric liquid pump control apparatus comprising:

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