Wide Speed Range Rotor Position Sensorless Control for Synchronous Reluctance Motors

Synchronous reluctance motors (SynRMs) have the advantages of high efficiency and low cost, while their sensorless control may further reduce the overall cost. In this work, a square wave high frequency injection approach and a sliding mode observer approach were combined to realize wide speed range sensolress control of an SynRM. It was found that the nonlinear inductance parameters and cross coupling effects of the motor severely deteriorated the accuracy of rotor position estimation at low and zero speeds. A novel compensation scheme based on an adaptive phase-locked-loop (PLL) was therefore proposed to address this issue. This article verifies the effectiveness of the proposed scheme through various simulation experiments. The results show that the improved scheme can effectively reduce rotor estimation errors and improve the dynamic and steady-state performance of an SynRM drive.