Abstract: Aiming at the nonlinear problem of SMC (Sliding Mode Control) of PMSM (Permanent Magnet Synchronous Motor), on the basis of analyzing the weak connection between the parameters of the sliding mode control at different stages, a fuzzy parameter tuning strategy is proposed to reduce overshoot, chattering and having certain anti-jamming ability. The major functions of various parameters and the relationship between parameters in the process of sliding mode motor control are improved. The fuzzy logic control is combined with the exponential reaching law. The change of sliding mode parameters is adjusted by fuzzy control, and the fuzzy reaching law is derived. The design method simplifies the complexity of sliding mode parameter adjustment and eliminates the constant speed term of exponential approach rate, making the design and regulation more convenient. The conclusions show that compared with the traditional sliding mode control of permanent magnet synchronous motor, the speed loop controller designed by making fuzzy control to adjust the sliding mode parameters can further reduce the overshoot by 21. 86%, reduce the start-up time by 0.038 s, effectively eliminate the buffeting peak wave when reducing the buffeting, and reduce the speed drop by 7. 31% when dealing with the sudden change of load. The adjustment time is reduced by 0. 010 s. The reliability and superiority of the parameters are verified. 

Key words: sliding mode control, permanent magnet synchronous motor(PMSM), fuzzy control, fuzzy approach rate