Direct Speed Composite Control of SPMSM Drive System

Abstract

The surface mounted permanent magnet synchronous motor (SPMSM) is a complex and nonlinear system. Therefore, single control method is difficult to perform well in different operations. For this reason, the direct speed composite control of SPMSM drive system is proposed in this paper. First, the control laws are deduced from the designed sliding mode surface and integral sliding mode surface under non-cascaded structure respectively. On the basis of guaranteeing the system stability, the dynamic weight factor is designed innovatively with speed error to perceive system state and allocate the ratio of two control laws in real time. Accordingly, the proposed composite control can be implemented by dynamic weight factor and make full use of two abovementioned control laws. Furthermore, by establishing ultra-local model of the SPMSM drive system, the nonlinearities, uncertainties and unknown disturbances of the system are estimated together and fed back to the controller, and the system robust improvement can be achieved consequently. At last, system simulation and experimental researches validate that the proposed direct speed composite control realizes smooth transition of two control methods and improves dynamic and steady-state control performance of the system.