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CN-113872474-B - Sensorless control device, electric oil pump device, and sensorless control method

CN113872474BCN 113872474 BCN113872474 BCN 113872474BCN-113872474-B

Abstract

A sensorless control device, an electric oil pump device, and a sensorless control method. The sensorless control device includes a motor drive circuit, a phase detection unit that outputs a phase detection signal based on a back electromotive force of a motor, a storage unit that stores a voltage control pattern and a speed control pattern, a voltage control unit that outputs a control voltage based on the voltage control pattern, and an energization control unit that controls a drive voltage and an energization switching speed based on the control voltage and the speed control pattern. When starting the motor, the voltage control unit changes the control voltage with time according to the voltage control pattern, and the energization control unit performs forced commutation control in which the energization switching speed is changed with time according to the speed control pattern while changing the drive voltage with time in synchronization with the control voltage. During the forced commutation control, the combination of the drive voltage and the energization switching speed at any timing always satisfies a linear function having a negative slope with the drive voltage and the energization switching speed as variables.

Inventors

  • SATO KEI

Assignees

  • 日本电产东测有限公司

Dates

Publication Date
20260505
Application Date
20210625
Priority Date
20200630

Claims (7)

  1. 1. A sensorless control apparatus that controls a motor without a position sensor, wherein, The sensorless control device includes: a motor drive circuit configured by switching elements of a plurality of phases, and supplying power to each phase of the motor; A phase detection unit that detects a phase of the motor from a back electromotive force of the motor, and outputs a phase detection signal indicating a detection result of the phase; A storage unit that stores a voltage control pattern indicating a control pattern of a driving voltage applied to an energized phase of the motor and a speed control pattern indicating a control pattern of an energized switching speed, which is a speed at which the energized phase is switched; A voltage control part for outputting a control voltage according to a control command signal input from a higher-level control device, the phase detection signal, and the voltage control pattern, and An energization control portion that controls the switching element of the motor drive circuit according to the control voltage, the phase detection signal, and the speed control pattern, thereby controlling the drive voltage and the energization switching speed, When the motor is started, if the phase cannot be recognized by the phase detection signal, the voltage control unit increases the control voltage with time according to the voltage control pattern, the energization control unit controls the switching element according to the control voltage and the speed control pattern, thereby performing forced commutation control in which the energization switching speed is reduced with time according to the speed control pattern while increasing the drive voltage with time in synchronization with the control voltage to stably rotate the motor to a rotational speed generating a counter electromotive force at a detectable zero-crossing point regardless of the magnitude of a load at the time of starting the motor, During the forced commutation control, the combination of the drive voltage and the energization switching speed at any timing always satisfies a linear function having the drive voltage and the energization switching speed as variables and having a negative slope.
  2. 2. The sensorless control apparatus of claim 1 wherein, The voltage control section increases the control voltage according to the voltage control pattern with time at a constant slope, The energization control unit controls the switching element based on the control voltage and the speed control pattern, thereby performing forced commutation control in which the energization switching speed is reduced in accordance with the speed control pattern with a constant slope over time while increasing the drive voltage in synchronization with the control voltage with a constant slope over time.
  3. 3. The sensorless control apparatus of claim 1 wherein, The voltage control section causes the control voltage to be increased stepwise with time in accordance with the voltage control pattern, The energization control unit controls the switching element based on the control voltage and the speed control pattern, thereby performing forced commutation control in which the energization switching speed is reduced stepwise over time based on the speed control pattern while the driving voltage is increased stepwise over time in synchronization with the control voltage.
  4. 4. The sensorless control apparatus of any one of claims 1 to 3, wherein, The storage unit stores in advance a DC excitation condition in which the phase of the motor is fixed to a specific phase, When the motor is started, if the phase cannot be recognized from the phase detection signal, the voltage control unit outputs the control voltage according to the dc excitation condition before outputting the control voltage according to the voltage control pattern, and the energization control unit controls the switching element according to the control voltage and the dc excitation condition, thereby applying a dc drive voltage for a certain period of time to a specific energized phase.
  5. 5. The sensorless control apparatus of any one of claims 1 to 3, wherein, When the phase is successfully recognized based on the phase detection signal, the voltage control unit outputs the control voltage based on the control command signal and the phase detection signal, and the energization control unit controls the switching element based on the control voltage and the phase detection signal, thereby switching the energized phase at an energization switching speed determined by the phase detection signal while applying a driving voltage corresponding to the control command signal to the energized phase.
  6. 6. An electric oil pump device, comprising: A motor having a shaft; a pump located on one axial side of the shaft and driven by the motor through the shaft to discharge oil, and The sensorless control apparatus of any one of claims 1-4 that controls the motor without a position sensor.
  7. 7. A sensorless control method for controlling a motor without a position sensor, wherein, When the motor is started, if the phase of the motor cannot be recognized, a forced commutation control is performed in which the switching speed of the energization as the switching speed of the energization is reduced with time according to a predetermined speed control pattern while the driving voltage applied to the energization of the motor is increased with time according to a predetermined voltage control pattern so as to stably rotate the motor to a rotational speed at which a counter electromotive force of a detectable zero crossing point is generated regardless of the magnitude of a load at the time of starting the motor, During the forced commutation control, the combination of the drive voltage and the energization switching speed at any timing always satisfies a linear function having the drive voltage and the energization switching speed as variables and having a negative slope.

Description

Sensorless control device, electric oil pump device, and sensorless control method Technical Field The invention relates to a sensorless control device, an electric oil pump device, and a sensorless control method. Background The hybrid vehicle includes a mechanical oil pump driven by a driving force of an engine and an electric oil pump driven by a motor as hydraulic pressure supply devices that supply hydraulic pressure to a transmission. In such a hybrid vehicle, the motor is controlled when the engine, in which the mechanical oil pump is not operable, is stopped, and thus the hydraulic pressure required for the transmission can be supplied by the electric oil pump. As a control method of the motor, there is known a sensorless control in which a phase of the motor is detected by a counter electromotive force of the motor without using a hall sensor or the like, and energization control of the motor is performed based on a detection result of the phase. In the sensorless control, in order to detect the phase of the motor, it is necessary to detect a zero crossing point, which is a point where the neutral point voltage of the motor intersects with the counter electromotive force, but if the rotational speed of the motor is not equal to or higher than a predetermined speed, no counter electromotive force capable of detecting the zero crossing point is generated. Therefore, when the motor is started by sensorless control, the energization control of the motor is generally performed in a predetermined starting sequence before the rotational speed of the motor reaches a speed at which the zero-crossing point can be detected. As an example of the starting sequence, a starting sequence is known in which, after the phase of the motor is fixed to a specific phase by dc excitation for a predetermined time, forced commutation control is performed in which the energized phase is forcibly switched at a constant energization switching speed while a constant driving voltage is applied to the energized phase. When the rotational speed of the motor reaches a speed at which a zero-crossing point can be detected by the start sequence, the forced commutation control is ended, and then the sensorless control of the motor is performed based on the phase detection result of the motor obtained by the detection of the zero-crossing point. Patent document 1 describes a method for starting a sensorless motor, in which when a detected pattern of zero crossings captured during forced commutation control matches a predetermined pattern of change, the method shifts from forced commutation control to sensorless control. In this starting method, when the pattern switching timing time at the time of forced commutation control is shorter than a predetermined time, the hysteresis control is performed and the control is shifted to the sensorless control. Patent document 1 Japanese patent laid-open No. 2008-271727 However, in order to properly rotate the motor, it is necessary to control the driving voltage V applied to the motor to an appropriate value corresponding to the rotation speed F in accordance with the F-V characteristic depending on the specification of the motor. Since the rotation speed F is proportional to the driving voltage V, the F-V characteristic can be expressed as a linear function having a positive slope. The more the combination of the rotation speed F and the driving voltage V deviates from the F-V characteristic, the more unstable the rotation of the motor, the more difficult it is to appropriately control the motor. In addition, when the motor is connected to a load such as an oil pump, the energy required for rotating the motor increases, and therefore, the drive voltage required for rotating the motor connected to the load at the same rotational speed as in the case of no load increases. That is, even with the same motor, the F-V characteristic of the motor varies depending on the load magnitude. In the case of starting the motor by the sensorless control as described above, the forced commutation control is performed in accordance with a combination of the predetermined driving voltage and the energization switching speed, but the actual rotation speed of the motor does not necessarily coincide with the energization switching speed, and depends on the magnitude of the driving voltage and the magnitude of the load. Therefore, it is preferable to obtain the F-V characteristics under various load conditions in advance by experiments, and when the motor is started by sensorless control, the forced commutation control is performed in accordance with a combination of the driving voltage and the energization switching speed suitable for the F-V characteristics corresponding to the actual load size, but it is actually difficult to implement the method. Therefore, as a practical method, there is often adopted a method of performing forced commutation control while adjusting a driving voltage and a current-carrying switchi