New antiwindup PI controller for variable-speed motor drives

The windup phenomenon appears and results in performance degradation when the proportional-integral (PI) controller output is saturated. A new antiwindup PI controller is proposed to improve the control performance of variable-speed motor drives, and it is experimentally applied to the speed control of a vector-controlled induction motor driven by a pulsewidth modulated (PWM) voltage-source inverter (VSI). The integral state is separately controlled, corresponding to whether the PI controller output is saturated or not. The experimental results show that the speed response has much improved performance, such as small overshoot and fast settling time, over the conventional antiwindup technique. Although the operating speed command is changed, similar control performance can be obtained by using the PI gains selected in the linear region.