Online Inductance Identification and Sensorless Control of PMSM Based on a Novel High-Frequency Square-Wave Injection

Permanent magnet synchronous motors are subject to harsh and complex operating environments and have high requirements for low-speed stability. To address the problems of motor inductance distortion and the difficulty of sensorless control at low speed, this paper first analyzes the shortcomings of the conventional square-wave injection method. Then, in order to achieve d- and q-axis incremental inductance and cross-coupling inductance identification by the same injection and simultaneously realize sensorless control, a novel high-frequency voltage injection wave and the separation method of self-excited and coupled-excited currents are proposed. The verification is carried out on the simulation platform and the permanent magnet synchronous motor test bench. The results show that under acceleration and deceleration as well as current variation, inductance identification and angle tracking can be realized accurately and quickly.