An improved model-free predictive current control for four-switch three-phase inverter-fed synchronous reluctance motor drives

Abstract

This paper proposes an improved model-free predictive current control (MFPCC) scheme for four-switch three-phase (FSTP) inverter-fed synchronous reluctance motor (SynRM) drive systems. Unlike the existing model-based predictive current control (MBPCC), the improved MFPCC does not need any motor parameters due to the current sensor based approach, where only once current measurement is required in each sampling interval. According to the measured stator current and pre-saved current differences, the future stator current can be predicted without estimating the back-EMF of motor. Next, a cost function is defined to compute all possible future current errors under four switching states generated by the FSTP inverter. The next switching state can be decided to control the FSTP in the next sampling interval to obtain the cost function. Additionally, a passivity-based adaptive backstepping complementary sliding-mode (PBABCSM) controller is adopted in this study to improve the position tracking performance of the FSTP inverter-fed SynRM drives. The stability of the closed-loop system has been verified through passivity theory and Barbalat's lemma. Furthermore, simulation results are provided to validate the effectiveness of the proposed method.