JP-7855963-B2 - Motor control method and motor control device

JP7855963B2JP 7855963 B2JP7855963 B2JP 7855963B2JP-7855963-B2

Inventors

森憲一

Assignees

日産自動車株式会社

Dates

Publication Date: 20260511
Application Date: 20220728

Claims (7)

A motor control method for controlling the power supplied to a motor based on a predetermined torque command value and an estimated magnetic pole position of the motor, A rotation speed parameter acquisition step is to acquire rotation speed parameters that indicate the rotation speed of the motor, The process includes a magnetic pole position calculation step which calculates the magnetic pole position based on power parameters that indicate the power of the motor, In the aforementioned magnetic pole position calculation step, The change in rotational speed is estimated from the rotational speed parameter, The magnetic pole position is corrected based on the change in rotational speed . In the aforementioned rotational speed parameter acquisition process, An estimated signal is generated for estimating the magnetic pole position, The estimated signal is superimposed on the power command value that defines the power to be supplied to the motor. Based on the power parameters, a response power value corresponding to the power command value with the estimated signal superimposed is calculated. Based on the response power value, the rotational speed parameter is calculated, The aforementioned power command value includes the dq axis voltage command value. The estimated signal includes a dq-axis high-frequency voltage, The aforementioned response power value includes the dq-axis response high-frequency current. The aforementioned power parameters include the dq axis current, In the aforementioned rotational speed parameter acquisition process, The dq-axis response high-frequency current is calculated by applying a filter to the detected value of the dq-axis current. Based on the dq-axis response high-frequency current, an estimated phase error value is calculated, which is determined as the phase difference between the dq-axis coordinate system and a pre-set two-axis control coordinate system. The estimated phase error is corrected by a predetermined error correction value to calculate a corrected estimated phase error. Based on the aforementioned corrected phase error estimate, the estimated electrical angular velocity and rotational speed, which are rotational speed parameters, are calculated. In the aforementioned magnetic pole position calculation step, Based on the estimated electrical angular velocity, the estimated phase value of the motor that suggests the magnetic pole position is calculated. The change in the rotational speed is calculated as the change in the estimated rotational speed, The error correction value is increased or decreased in accordance with the change in the estimated rotational speed. The process further includes a mode selection step of selecting either a rotational speed control mode or a torque control mode in accordance with a predetermined control mode signal. The rotational speed control mode is a control mode in which a first torque command value determined from the rotational speed command value which is the rotational speed that the motor should output is set as the torque command value, and the power command value is calculated based on the first torque command value and the rotational speed estimate value. The torque control mode is a control mode in which a second torque command value, which is determined as the torque that the motor should output, is set as the torque command value, and the power command value is calculated based on the second torque command value and the rotational speed estimate value. When the aforementioned rotation speed control mode is selected, In the rotation speed parameter acquisition step, the rotation speed command value is calculated as the rotation speed parameter, When the torque control mode is selected, the rotational speed estimate is calculated using the rotational speed parameter. Motor control method.
A motor control method according to claim 1 , In the aforementioned magnetic pole position calculation step, Based on the change in the estimated rotational speed and the q-axis current, the error correction value is adjusted. Motor control method.
A motor control method according to claim 2 , In the aforementioned magnetic pole position calculation step, The larger the absolute value of the q-axis current, the larger the error correction value. Motor control method.
A motor control method according to claim 1 , In the aforementioned magnetic pole position calculation step, Depending on the direction of change of the estimated rotational speed, the sign of the error correction value is switched. Motor control method.
A motor control method according to claim 1 , In the aforementioned magnetic pole position calculation step, The larger the change in the estimated rotational speed, the larger the error correction value. Motor control method.
A motor control method according to claim 1 , In the aforementioned magnetic pole position calculation step, The error correction value is adjusted based on the change in the estimated rotational speed and the amplitude ratio of the q-axis high-frequency voltage to the d-axis high-frequency voltage. The smaller the amplitude ratio, the larger the error correction value. Motor control method.
A motor control device that controls the power supplied to the motor based on a predetermined torque command value and the estimated magnetic pole position of the motor, A rotation speed parameter acquisition unit that acquires rotation speed parameters that indicate the rotation speed of the motor, The system includes a magnetic pole position calculation unit that calculates the magnetic pole position based on power parameters that indicate the power of the motor, The aforementioned magnetic pole position calculation unit is: The change in rotational speed is estimated from the rotational speed parameter, The magnetic pole position is corrected based on the change in rotational speed. The rotation speed parameter acquisition unit, An estimated signal is generated for estimating the magnetic pole position, The estimated signal is superimposed on the power command value that defines the power to be supplied to the motor. Based on the power parameters, a response power value corresponding to the power command value with the estimated signal superimposed is calculated. Based on the response power value, the rotational speed parameter is calculated, The aforementioned power command value includes the dq axis voltage command value. The estimated signal includes a dq-axis high-frequency voltage, The aforementioned response power value includes the dq-axis response high-frequency current. The aforementioned power parameters include the dq axis current, The rotation speed parameter acquisition unit, The dq-axis response high-frequency current is calculated by applying a filter to the detected value of the dq-axis current. Based on the dq-axis response high-frequency current, an estimated phase error value is calculated, which is determined as the phase difference between the dq-axis coordinate system and a pre-set two-axis control coordinate system. The estimated phase error is corrected by a predetermined error correction value to calculate a corrected estimated phase error. Based on the aforementioned corrected phase error estimate, the estimated electrical angular velocity and rotational speed, which are rotational speed parameters, are calculated. The aforementioned magnetic pole position calculation unit is: Based on the estimated electrical angular velocity, the estimated phase value of the motor that suggests the magnetic pole position is calculated. The change in the rotational speed is calculated as the change in the estimated rotational speed, The error correction value is increased or decreased in accordance with the change in the estimated rotational speed. The system further includes a mode selection unit that selects either a rotational speed control mode or a torque control mode in accordance with a predetermined control mode signal. The rotational speed control mode is a control mode in which a first torque command value determined from the rotational speed command value which is the rotational speed that the motor should output is set as the torque command value, and the power command value is calculated based on the first torque command value and the rotational speed estimate value. The torque control mode is a control mode in which a second torque command value, which is determined as the torque that the motor should output, is set as the torque command value, and the power command value is calculated based on the second torque command value and the rotational speed estimate value. When the aforementioned rotation speed control mode is selected, The rotation speed parameter acquisition unit calculates the rotation speed command value as the rotation speed parameter, When the torque control mode is selected, the rotational speed estimate is calculated using the rotational speed parameter. Motor control device.

Description

This invention relates to a motor control method and a motor control device. Patent Document 1 discloses a control method that determines command values for a two-axis coordinate system (d-axis/q-axis coordinate system) by referring to the magnetic pole position of a motor, and uses these command values to control the motor's drive. In this control method, the magnetic pole position of the motor is estimated from the detected value of the current flowing through the motor. More specifically, an AC signal for estimating the magnetic pole position is superimposed on the d-axis component (d-axis command value) of the command value mentioned above to drive the motor, and the magnetic pole position is estimated based on the q-axis component (q-axis current detection value) of the current detection value acquired in that state. Japanese Patent Application Publication No. 10-323099 Figure 1 is a block diagram showing the configuration of a motor control device according to one embodiment of the present invention.Figure 2 is a block diagram showing the configuration of the rotation state estimation unit.Figure 3 is a graph illustrating an example of how to determine the phase error correction value according to the rotational speed change rate and the q-axis current.Figure 4 is a graph illustrating an example of how to determine the phase error correction value according to the voltage amplitude ratio.Figure 5 is a flowchart showing the flow of estimation for motor rotation speed and magnetic pole position. The embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a block diagram showing the configuration of the motor control device 100. As shown in Figure 1, the motor control device 100 is assumed to be a device that, instead of measuring the magnetic pole position (rotor position) and rotational speed (hereinafter referred to as "motor rotational speed N") of the motor 200 with sensors such as resolvers and encoders, calculates these based on an estimation algorithm described later, and uses the calculated estimated value to operate the inverter 18 and control the power supplied to the motor 200. In other words, the motor control system of this embodiment, consisting of the motor control device 100, inverter 18, and motor 200, can be configured as a position sensorless system. In particular, the motor 200 to be controlled is assumed to be an on-board motor for driving or a power generation motor. Furthermore, the motor 200 is, for example, a three-phase AC IPM (Interior Permanent Magnet) motor and is configured as a saliency motor in which the q-axis inductance Lq and the d-axis inductance Ld show mutually different values. The motor control device 100 comprises a rotation speed control unit 8, a torque command value selection unit 9, a current command generation unit 11, a first voltage command generation unit 12, a second voltage command generation unit 13, a final voltage command generation unit 14, a control mode signal generation unit 15, a coordinate transformation unit 16, a PWM conversion unit 17, a rotation state estimation unit 19, and a coordinate transformation unit 23. The motor control device 100 is configured by a computer (controller) equipped with programs to realize the functions of each unit. Furthermore, the hardware constituting this computer may consist of one or more units. The rotational speed control unit 8 calculates and outputs a first torque command value T rev * based on the rotational speed command value N * input from the higher-level control unit and the rotational speed estimate value N' input from the rotational state estimation unit 19. Here, the rotational speed command value N * is determined as the rotational speed of the motor 200 (hereinafter also referred to as "motor rotational speed N") which is determined from the desired required power generation (engine torque × engine rotational speed) when the motor 200 is used as a generator that generates power by regenerating power using a predetermined drive source (such as an engine). In other words, the rotational speed command value N * is the target value of the rotational speed that the motor 200 should output, as determined by the higher-level control device. The rotational speed estimate value N' is an estimated value of the motor rotational speed N calculated according to the control state of the motor 200. The rotational speed estimate value N' is calculated (estimated) by the rotational state estimation unit 19 according to the estimation algorithm (high-frequency voltage application method) described later. Furthermore, the first torque command value T rev * is the target value of the output torque of the motor 200 that should be aimed for in order to achieve the above rotational speed command value N * . More specifically, the rotational speed control unit 8 calculates the first torque command value T rev * by performing PI (Proportional-Integral) control based on th