Thrust Ripple Reduction in Permanent Magnet Synchronous Linear Motor Based on Electromagnetic Damping-Spring System

This paper proposes an electromagnetic damping-spring system (ED-SS) to reduce the thrust ripple of permanent magnet synchronous linear motor (PMSLM), which is applied to the laser cutting machine. This approach uses restraining force of ED-SS that offsets the ripple force to decrease the thrust ripple. First, the ED-SS is designed with the structure and motion characteristics of PMSLM. The equivalent magnetization method is used to analyze the PMSLM thrust. Simultaneously, the ripple force is obtained and acted as the excitation of ED-SS. Next, the equivalent surface current method and the virtual work principle are utilized to express the restraining force characteristics and the relationship among the designed parameters of ED-SS. The standard deviation of PMSLM thrust is selected as an index to evaluate the magnitude of thrust ripple. Finally, simulation is performed to verify the validity of the theory analysis. The prototype of PMSLM with ED-SS is manufactured and three prototype experiments are conducted. The experimental results verify the validity of the proposed approach.