Improved Sliding-Mode Speed Control of Permanent Magnet Synchronous Motor Based on Working Condition Identification

An improved approach law sliding mode control strategy is proposed on the basis of conventional sliding mode control to improve the tracking and anti-interference performance of permanent magnet synchronous motor (PMSM) speed regulation system. Firstly, the constant speed term of the conventional exponential reaching law is replaced by a power term, and working condition identification is introduced into the power term index and other controller parameters to associate the parameters with system working conditions, so as to solve the problems of large overshoot and long adjustment time when the conventional reaching law reaches the sliding mode surface, and reduce the impact of load disturbance on the system at the same time. Secondly, in the face of the problem that a single control method can not achieve the optimize performance index of PMSM in various motion stages, this paper proposes an adaptive conversion mechanism of performance index, and constructs a working condition identification strategy based on finite state machine. According to the system working condition label, the control target of the system is switched reasonable, so that the customized control strategy can be realized. Simulation results show that the proposed sliding mode adaptive control strategy based on working condition identification can improve the dynamics and robustness of the system more effectively than conventional sliding mode control strategy.