Non-Cascaded Model-Free Predictive Speed Control of SMPMSM Drive System

Abstract

The cascaded structure is generally adopted in the permanent magnet synchronous motor drive system, however, the speed dynamic performance is always deteriorated due to the limited bandwidth of speed loop when the linear controller is employed. Therefore, in order to realize quick dynamic response, the speed loop is eliminated in the non-cascaded control structure, and the non-cascaded model-free predictive speed control is proposed in this paper. First, the ultra-local model of SMPMSM drive system is established with a compound variable which implicitly unifies the speed and current of different time scales, and then the Lyapunov function is designed to derive control law and generate the inverter reference voltage automatically by considering the delay of digital control. Moreover, the inverter reference voltage is further modified under voltage and current constraints to guarantee system safety and reliable operation. Finally, the feasibility and validity of the proposed method has been verified by system simulation and experimental researches.