Adaptive Fuzzy PI Speed Controller Gains for Permanent Magnet Synchronous Motor

The conventional proportional integral (PI) and proportional integral derivative (PID) controllers have been widely utilised as speed controllers in PMSM drives. However, the conventional fixed-gain PI and PID controllers are very sensitive to step change of command speed, parameter variations and load disturbance. To overcome the drawbacks of the fixed gains PI controller, an adaptive fuzzy logic controller is presented in this paper to tune the PI controller gains online. The proposed adaptive fuzzy logic controller processes the speed error and adjusts the PI controller gains automatically to achieve the desired response under different operating conditions. The fuzzy rule base is designed and optimised to achieve the desired control response such as rise time, overshoot and steady state error. The performance of the proposed controller is examined, by simulation using Simulink/Matlab at different operating conditions. The operating conditions studied included various step speed commands from standstill with nominal and changes in motor parameters and load torque. The results obtained were evaluated and compared with the fixed-gains PI controller. The simulation results showed the superiority of the adaptive controller over the conventional fixed-gain PI controller especially for load disturbances and load inertia variations.