Study on Compensating the Dead Zone Effect in High-Frequency Square Wave Injection Scheme

Aiming at the distortion of the output current caused by non-ideal switching characteristics in the position sensorless control system of permanent magnet synchronous motors (PMSM), which will lead to deviations in rotor position detection, a method of current zero crossing detection is carried out in this paper and it successfully decreases the dead zone's impact on high-frequency square wave(HFSW) injection in position sensorless control system. Compared with the scheme without dead zone compensation, it effectively improves the current waveform distortion and reduces the steady-state error and phase lag of the system. Both simulation and experimental results verify the correctness of the strategy and good performance of the system.