CN-121984401-A - Initial electrical angle self-calibration method, device and storage medium for servo motor control

CN121984401ACN 121984401 ACN121984401 ACN 121984401ACN-121984401-A

Abstract

The application relates to the technical field of servo motor control, and provides an initial electrical angle self-calibration method, device and storage medium for servo motor control. The method comprises the steps of controlling a power circuit to inject preset direct current exciting current into windings of a servo motor by a controller to generate a stator composite magnetic field with a fixed direction, dragging and aligning a rotor permanent magnet to the fixed stator composite magnetic field direction, reading an aligned mechanical angle output by a magneto-electric encoder after judging that the rotor is aligned stably, calculating and obtaining an electrical angle offset between an installation zero point of the magneto-electric encoder and an electrical zero point of the servo motor, storing the electrical angle offset in a nonvolatile memory as a control parameter, completing initial electrical angle self-calibration, calculating in real time based on the electrical angle offset stored in the nonvolatile memory after the self-calibration control flow is completed to obtain a real-time electrical angle for executing magnetic field directional control, and executing magnetic field directional control on the servo motor by the controller based on the real-time electrical angle.

Inventors

ZENG XIAOHU
LIU CHENGLONG
GONG QILONG

Assignees

深圳市顾美科技有限公司

Dates

Publication Date: 20260505
Application Date: 20260403

Claims (10)

1. An initial electrical angle self-calibration method for servo motor control, applied to a servo integrated machine comprising a servo motor, a magneto-electric encoder, a drive board and a nonvolatile memory, characterized in that the method comprises a self-calibration control flow executed by a controller of the drive board: after the servo integrated machine is electrified, executing a first-time electrifying self-calibration flow, wherein the first-time electrifying self-calibration flow comprises: The controller controls a power circuit to inject preset direct current exciting current into a winding of the servo motor so as to generate a stator composite magnetic field with a fixed direction, performs rotor alignment control, and pulls and aligns a rotor permanent magnet to the fixed stator composite magnetic field direction; after the rotor alignment is judged to be stable, reading an alignment mechanical angle output by the magneto-electric encoder; According to the alignment mechanical angle and a preset reference electric angle phase, calculating and obtaining an electric angle offset between the installation zero point of the magneto-electric encoder and the electric zero point of the servo motor; storing the electrical angle offset as a control parameter in the nonvolatile memory to complete initial electrical angle self-calibration; After the self-calibration control flow is finished, the controller reads the mechanical angle of the magneto-electric encoder in real time, and calculates the real-time electrical angle for executing magnetic field orientation control in real time based on the electrical angle offset stored in the nonvolatile memory; based on the real-time electrical angle, magnetic field orientation control is performed on the servo motor by the controller.
2. The method of claim 1, wherein the controller controlling the power circuit to inject a preset dc excitation current into the windings of the servo motor to generate a stator resultant magnetic field with a fixed direction comprises: setting a d-axis current given value of a current loop to be zero, and setting a q-axis current given value to be a non-zero constant value; In space vector modulation control, the electric angle input is forcedly set to an angle value consistent with the preset reference electric angle phase; And executing current closed-loop control, so that the phase current of the motor is stabilized at the q-axis current set value and maintains the preset excitation time length, and generating the stator composite magnetic field with fixed direction.
3. The initial electrical angle self-calibration method for servo motor control according to claim 1 or 2, wherein said determining that said rotor alignment is stable is accomplished by said controller by the following monitoring and determining steps: after the direct-current exciting current is injected to reach the preset exciting duration, continuing to maintain the exciting current for a first time delay; Monitoring, by a controller, a rate of change of the mechanical angle read by the magneto-electric encoder during the first time delay; and when the mechanical angle change rate is smaller than a preset stability threshold value, the controller judges that the rotor is aligned and stable.
4. The method for self-calibration of an initial electrical angle for servo motor control according to claim 1, wherein said calculating and obtaining an electrical angle offset between a mounting zero of said magneto-electric encoder and an electrical zero of said servo motor based on said alignment mechanical angle and a preset reference electrical angle phase comprises: multiplying the alignment mechanical angle by the pole pair number of the servo motor to obtain an original electrical angle corresponding to the rotor position at the alignment moment; Calculating a difference between the original electrical angle and the preset reference electrical angle phase; and performing a modulo 360 operation on the difference value to obtain the electrical angle offset in the range of 0 to 360 degrees.
5. The method for self-calibration of an initial electrical angle for servo motor control according to claim 4, further comprising a validity checking step performed by a controller for said electrical angle offset as follows, before said completing of initial electrical angle self-calibration: reversely deducing a theoretical mechanical angle which is required to be read by the magneto-electric encoder under the condition of no offset according to the calculated electrical angle offset; Under the condition of maintaining exciting current, the actual mechanical angle of the magneto-electric encoder is read again; Calculating the deviation of the actual mechanical angle and the theoretical mechanical angle; And judging whether the deviation is smaller than a preset verification threshold value by the controller, and controlling the flow trend according to the deviation, wherein if the deviation is smaller than the preset verification threshold value, the operation of storing the electric angle offset into the nonvolatile memory as a control parameter is performed to finish calibration, and if not, the first power-on self-calibration flow is re-performed.
6. The method of claim 1, further comprising a fast start control procedure performed by the controller when not first powered up: After power-on, the controller reads the electrical angle offset and the check code from the designated address of the nonvolatile memory; If the verification is passed, the control flow skips the first power-on self-calibration flow, and the calculation of the real-time electrical angle and the magnetic field directional control are directly executed based on the read offset, so that the quick start is realized; if the verification fails or the reading fails, the control flow automatically triggers and executes the first power-on self-calibration flow.
7. The initial electrical angle self-calibration method for servo motor control according to claim 6, further comprising the steps of on-line monitoring control, abnormality determination control and self-repairing control performed by the controller during operation as follows: On-line monitoring control, wherein when the servo integrated machine normally operates in a speed or torque mode based on the real-time electrical angle, the controller monitors the back electromotive force waveform or current harmonic characteristic of the motor; An abnormality determination control of determining, by the controller, that the stored electrical angle offset is likely to fail when it is determined that there is an out-of-tolerance deviation of the calculated real-time electrical angle from the actual electrical angle of the motor based on the monitoring feature; And repairing and triggering control, namely triggering alarm, recording an event, and controlling the servo integrated machine to forcedly enter the first power-on self-calibration flow when the servo integrated machine is powered on next time so as to update the control parameters.
8. An initial electrical angle self-calibration device for servo motor control is applied to a servo integrated machine comprising a servo motor, a magneto-electric encoder, a driving plate and a nonvolatile memory, the device is characterized by comprising the following modules for executing a first power-on self-calibration flow after a servo integrated machine is powered on: The alignment module is used for controlling a power circuit to inject preset direct-current exciting current into a winding of the servo motor by a controller of the driving board so as to generate a stator composite magnetic field with a fixed direction, executing rotor alignment control, and dragging and aligning a rotor permanent magnet to the fixed stator composite magnetic field direction; the reading module is used for reading the alignment mechanical angle output by the magneto-electric encoder after judging that the alignment of the rotor is stable; the calculation module is used for calculating and obtaining the electrical angle offset between the installation zero point of the magneto-electric encoder and the electrical zero point of the servo motor according to the alignment mechanical angle and the preset reference electrical angle phase; the storage module is used for storing the electric angle offset as a control parameter in the nonvolatile memory to finish initial electric angle self-calibration; The calculation module is used for reading the mechanical angle of the magneto-electric encoder in real time by the controller after the self-calibration control flow is finished, and calculating in real time based on the electrical angle offset stored in the nonvolatile memory to obtain a real-time electrical angle for executing magnetic field orientation control; and the execution module is used for executing magnetic field orientation control on the servo motor by the controller based on the real-time electrical angle.
9. An electronic device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the steps of the method according to any one of claims 1 to 7 when the computer program is executed by the processor.
10. A storage medium storing a computer program which, when executed by a processor, implements the steps of the method according to any one of claims 1 to 7.

Description

Initial electrical angle self-calibration method, device and storage medium for servo motor control Technical Field The application relates to the technical field of servo motor control, in particular to an initial electrical angle self-calibration method, device and storage medium for servo motor control. Background The servo integrated machine is widely applied in the field of industrial automation due to the characteristic of high integration. Which typically includes a servo motor, a magneto-electric encoder, and a drive control board. Magneto-electric encoders are used to detect the absolute mechanical position of the motor rotor and are critical to achieving high-precision Field Oriented Control (FOC). However, due to mechanical assembly tolerances, there is typically a fixed angular offset of the mechanical zero position of the magneto-electric encoder from the electrical zero position (i.e., the U-phase axis) of the servo motor windings, which is referred to as the electrical angular offset. If this offset is not accurately known, the control system will not be able to calculate the correct electrical angle from the encoder readings, resulting in control failure, torque ripple, or start-up failure. Currently, in order to obtain this key parameter, it is common practice to perform an initial electrical angle identification procedure once every time the servo system is powered on and started. The process typically involves injecting a specific test signal into the motor windings to cause the rotor to rotate to a known electrical position, while simultaneously reading the mechanical position fed back by the encoder, and by calculating the difference between the two to identify the current electrical angular offset in real time and for the control solution for the current run. However, the above prior art scheme has a significant disadvantage that since the electrical angle offset is a fixed value determined by mechanical installation, the electrical angle offset is not generally changed in the life cycle of the servo integrated machine, but the prior art method needs to repeatedly execute a complete identification process every time power is applied. This repetitive operation inevitably introduces additional start-up time delay, reducing the system response speed. Particularly, in the application occasions requiring frequent start-stop or having higher requirements on the start-up speed, the identification waiting time of each power-up is accumulated, and the working beat and the production efficiency of the equipment are directly affected. Therefore, how to avoid unnecessary repeated identification of the fixed parameters, thereby improving the starting efficiency of the servo system is a problem to be solved. Disclosure of Invention The application provides an initial electrical angle self-calibration method, device and storage medium for servo motor control, which avoid repeated execution of initial electrical angle identification after each power-on by a mechanism of 'one-time self-calibration, storage and multiple multiplexing', thereby remarkably improving the starting efficiency and response speed of a servo system. In one aspect, the present application provides an initial electrical angle self-calibration method for servo motor control, applied to a servo integrated machine including a servo motor, a magneto-electric encoder, a drive board, and a nonvolatile memory, the method including a self-calibration control flow executed by a controller of the drive board: after the servo integrated machine is electrified, executing a first-time electrifying self-calibration flow, wherein the first-time electrifying self-calibration flow comprises: The controller controls a power circuit to inject preset direct current exciting current into a winding of the servo motor so as to generate a stator composite magnetic field with a fixed direction, performs rotor alignment control, and pulls and aligns a rotor permanent magnet to the fixed stator composite magnetic field direction; after the rotor alignment is judged to be stable, reading an alignment mechanical angle output by the magneto-electric encoder; According to the alignment mechanical angle and a preset reference electric angle phase, calculating and obtaining an electric angle offset between the installation zero point of the magneto-electric encoder and the electric zero point of the servo motor; storing the electrical angle offset as a control parameter in the nonvolatile memory to complete initial electrical angle self-calibration; After the self-calibration control flow is finished, the controller reads the mechanical angle of the magneto-electric encoder in real time, and calculates the real-time electrical angle for executing magnetic field orientation control in real time based on the electrical angle offset stored in the nonvolatile memory; based on the real-time electrical angle, magnetic field orientation control is performed on the servo