Adaptive notch filter based harmonic self-compensated sliding-mode observer for position sensorless IPMSM drives

To suppress the position error harmonic ripples in back electromotive force (EMF) based methods for position sensorless interior permanent magnet synchronous motor (IPSMSM) drives, an adaptive notch filter (ANF) based harmonic self-compensated sliding-mode observer (SMO) is proposed. The inverter nonlinearities and flux spatial harmonics that induce the position error harmonic ripples are analyzed. The back-EMF information containing harmonics can be obtained through SMO, and then the least mean square (LMS) based ANF is adopted to realize back-EMF harmonic detecting and self-compensating, thus eliminating the position error harmonic ripples. Due to the simple structure, the ANF based harmonic self-compensated SMO can be easily implemented on low-cost microchips with little computational burden. Experiments on a 2.2kW IPMSM sensorless vector controlled drive have been carried out to verify the proposed scheme.