Sensorless DPCC of PMLSM Using SOGI-PLL Based High-Order SMO with Cogging Force Feedforward Compensation

Abstract

Due to the merits of high thrust force capability, high power factor, and high efficiency, permanent magnet linear synchronous motor (PMLSM) have been used in urban rail transit and electromagnetic launch systems. To reduce the thrust force ripple and cost for PMLSM drive system, the deadbeat predictive current control (DPCC) with equivalent current feedforward compensation control strategy and a sensorless speed and position estimation technology based on high-order sliding mode observer (SMO) and second order generalized integrator phase locked loop (SOGI-PLL) are proposed in this paper. The Fourier analysis method is used to fit the cogging force ripples obtained by finite element method. The DPCC with the feedforward compensation current could effectively improve the dynamic performance and reduce the thrust ripple of PMLSM. A high-order SMO is used to replace the traditional second-order SMO combined with a low-pass filter (LPF) to avoid the phase delay caused by LPF. SOGI-PLL technology is adopted to eliminate the harmonics caused by sliding mode chattering of the estimated back-EMF component. The simulation model and experimental platform are built. The simulation analyses and test results show that the proposed method has better performance than conventional techniques.