Fuzzy self-adapting PID control of PMSM servo system

The parameters of PID controller are needed to adjust on-line to satisfy the high performance requirement, because the external disturbance to PMSM servo system is random and the controlled object often varies with the work condition variation. The PMSM servo system is nonlinear, time-varying, and complex system. The traditional self adapting control is very difficult to realize, which need the on-line identification to the system characteristic parameters and the real-time change of control strategy. A new fuzzy self-adapting PID control method is proposed in this paper, which synthesizes the merits of fuzzy control and PID control. Using fuzzy inferences method, the PID parameters can be adjusted adaptively on-line for the varying state of the system. For the PMSM speed adjustment system, the vector control is used in current loop and fuzzy self-adjusting PID control is used in speed loop instead of traditional PI control. The effectiveness of the proposed control method is verified by simulation based on Matlab. The controller has better performance and robustness than conventional PI controller in the PMSM servo system.