A Novel Filter Time Delay Compensation Algorithm of Sliding Mode Observer for PMSM Sensorless Control

This paper proposes a method to compensate for the phase lag caused by the low-pass filter (LPF) in sliding mode observer (SMO). The lag time is calculated through the input and output of LPF, then the lag phase is calculated through the lag time and electrical angular velocity estimated by SMO. The lag phase is added to the estimated rotor position to obtain the precise rotor position. The sliding window algorithm is adopted to get the local extremum, but it is unsuitable for low-speed situations because of limited elements. Therefore, the traditional phase compensation method is used when the speed is low, and a switching process is designed to achieve full-speed phase compensation. The effectiveness of the proposed method is verified by simulation in Simulink.