Sensorless DPCC of PMLSM Using SOGI-PLL Based High-Order SMO with Cogging Force Feedforward Compensation
permanent magnet linear synchronous motor (PMLSM)， sensorless control， predictive current control ，thrust fluctuation ，sliding mode observer (SMO)， second order generalized integrator phase locked loop (SOGI-PLL).
Control methods for linear drives
Final Paper
Shilong Sun / China University of Mining and Technology
Abstract —In this paper, 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) is proposed. A high-order SMO is used to replace the traditional second-order SMO combined with a low-pass filter to avoid the phase delay caused by low-pass filter. Using SOGI-PLL technology can well eliminate the harmonics of the estimated back-EMF component. For PMLSM used in rail transit, due to the end and slot effect, the thrust output has a large thrust ripple, which will adversely affect the robustness of the sensorless control system. In this paper, a method is proposed to simulate the thrust fluctuation by using finite element method, fit the function of the thrust fluctuation with respect to the position by Fourier analysis, and then carry out the equivalent current feedforward compensation of the thrust fluctuation. Due to introducing the equivalent compensation current into the current loop, deadbeat predictive current control (PCC) is adopted to replace the traditional PI controller as the current loop controller in order to obtain faster current loop response.
