Two-time-scale Control of High-speed Permanent Magnet Synchronous Motors

A two-time-scale control strategy of high-speed permanent magnet synchronous motors (HSPMSMs) is proposed in this paper. HSPMSMs including mechanical part and electromagnetic part possess two-time-scale characteristic. Singular perturbation theory is adopted to model the two-timescale dynamic behavior. The model is then decomposed into slow and fast subsystems. With the consideration of disturbances in both slow and fast subsystems, H∞ controller and sliding mode controller are designed for slow and fast subsystems, respectively. Stabilities of the two subsystems are proven using Lyapunov theory separately. A composite controller is developed by combining the two subcontrollers, and the stability of the whole system is analyzed. Control performance of HSPMSM is verified through simulation experiments. Results show that the parallel-connection dual-loop two-time-scale control presents clear advantages over series-connection dual-loop PI control.