Method for suppressing speed ripple by using torque compensator based on activation function

Abstract

Disclosed is a method for suppressing a speed ripple occurring during an operation of an AC motor by using a torque compensator based on an activation function. The method includes the steps of calculating a speed error ωbased on a reference speed ωand an actual speed ω; calculating a controller output Tby using the speed error ωas an input of a PI control and an operation of a compensated torque T; and determining a torque variation based on the controller output Tand a reference torque Tand operating the torque variation in relation to an anti-windup gain Kto use torque variation as an input of an integral (I) control. The method suppresses the speed ripple by compensating for the torque ripple through a controller which calculates the compensated torque by taking the signs of the speed error and the differential speed error into consideration.