Composite control method for permanent magnet linear motor

An important factor which could hinder its smooth speed response for a permanent magnet linear motor (PMLM) is the inherent force ripple, and how to suppress the force ripple must be taken into account in the design of the system controller. In this paper, a three tier composite control structure is adopted based on the established PMLM model. An adaptive feedforward compensator is designed to eliminate or suppress the effects of the force ripple. Experiments to verify the feasibility of this method, and experimental results show that the application of such adaptive feedforward compensator can significantly improve the response performance of the system.