A rotor initial position detection method and system based on motor common mode current

Abstract

The invention discloses a rotor initial position detection method and system based on the common mode current of the motor. The detection method includes: alternately applying a zero-vector voltage pulse signal with a fixed duty ratio to the three-phase windings of the motor A, B and C when the motor is stationary ; Use oversampling technology to obtain current signals within a fixed time interval of a PWM cycle zero vector action; extract two-phase high-frequency oscillating currents through moving average filtering; improve the accuracy of two-phase high-frequency oscillating currents through repeated learning, and extract two-phase high-frequency oscillation currents; Frequency oscillating current amplitude; the two-phase high-frequency oscillating current amplitude is per unitized, and the mapping of the rotor position is realized by constructing a vector. The present invention also provides a system for realizing the above method. The invention can obtain the position information of the rotor without high-frequency signal injection, can avoid additional voltage signal injection, has strong applicability, and has no noise and no extra loss.

Description

technical field [0001] The invention belongs to the field of AC motor drive, and in particular relates to a method and system for detecting the initial position of a rotor based on the common mode current of the motor, aiming at estimating the position of the rotor by using the inherent common mode current of a frequency converter drive system. Background technique [0002] High-efficiency and high-power-density Permanent Magnet Synchronous Machines (PMSM) have been widely used in new-generation electric vehicles, high-speed EMU train drive systems, and aerospace actuation systems. To ensure the excellent performance of these drive systems, accurate rotor position and speed information acquisition is essential. Traditional permanent magnet synchronous motor drive systems all use position sensors to measure rotor position and speed, but position sensors and their signal transmission cables will inevitably fail and damage in complex electromagnetic environments and harsh worki...

AI Technical Summary

Problems solved by technology

Although there are many literatures that have observed this current, the underlying mechanism of charging and discharging the parasitic capacitance of the motor through the winding of the inverter switching instantaneous power is not fully utilized.

Therefore, there is no research on the rotor position estimation of permanent magnet motors from the perspective of common-mode high-frequency oscillating currents

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