Modified fuzzy logic PI speed controller with scheduling boundaries of integral time constant for PMSM drive

Abstract

In order to obtain high performance speed response in pulse-width-modulation direct torque controlled drive of permanent magnet synchronous motor, fuzzy logic is utilized to update parameters of proportional-integral speed controller. However, overshoot and undershoot of speed response are still high, especially at times of load torque change. For reduction of the overshoot and undershoot, boundaries of integral time constant in fuzzy logic are tuned according to speed error during overshoot and undershoot. Theoretical assumptions are validated via simulations.