A method for measuring inductance of permanent magnet synchronous motor based on limit cycle oscillation

CN114629404BActive Publication Date: 2026-06-19LEADRIVE TECH (SHANGHAI) CO LTD +1

Patent Information

Authority / Receiving Office: CN · China
Patent Type: Patents(China)
Current Assignee / Owner: LEADRIVE TECH (SHANGHAI) CO LTD
Filing Date: 2022-03-11
Publication Date: 2026-06-19

AI Technical Summary

Technical Problem

In traditional methods for calibrating the inductance parameters of permanent magnet synchronous motors, inaccurate measurements of voltage, current, and torque lead to inaccurate inductance parameter calibration, making verification difficult.

Method used

By bringing the motor control system into a steady state, adjusting the control parameters to cause it to become unstable and enter a critical oscillation state, measuring the oscillation frequency of the closed-loop system current waveform, constructing the system's open-loop transfer function, adjusting the motor inductance value so that the crossover frequency of the open-loop transfer function is the oscillation frequency of the actual closed-loop system, and recording the motor inductance value.

Benefits of technology

It achieves accurate measurement of inductance parameters, solves the problem of inaccurate inductance parameters caused by zero bias in traditional methods, and improves the accuracy of inductance parameter calibration.

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Abstract

This invention provides a method for measuring the inductance of a permanent magnet synchronous motor based on limit cycle oscillation. The method includes: bringing the motor control system to a steady state; adjusting the control parameters in the control system to cause instability and enter a critical oscillation state; measuring the critical oscillation frequency of the closed-loop system current waveform; constructing the system's open-loop transfer function; adjusting the motor inductance value L so that the crossover frequency of the open-loop transfer function is the critical oscillation frequency of the actual closed-loop system; and recording the current motor inductance value L, which is then the inductance of the permanent magnet synchronous motor under the current operating condition. This invention solves the technical problem of inaccurate inductance parameters calibrated by traditional inductance calibration methods due to zero bias and inaccurate voltage, current, and torque measurements, effectively achieving the goal of accurate measurement of inductance parameters.

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