Estimated Position Error Suppression Using PLL with Speed Compensation for Sensorless IPMSM Drives

Accurate rotor position information is important for the high-performance operation of position sensorless permanent magnet synchronous motor drives. However, during steady-state operation and variable speed conditions, traditional sliding mode observer with phase-locked loop (PLL) causes position estimation error. In this paper, an observer designed in rotary reference frame is proposed to reduce position estimation error during steady-state operation. Besides, a PLL with speed compensation is proposed to suppress the position estimation error caused in variable speed conditions. Experiments and simulation results verify the effectiveness of these two methods for position estimation error suppression.