Anti-Windup Control Considering the Acceleration Torque Component for the Speed Control System of an AC Servo

Abstract

The speed control system of an AC servomotor generally comprises a proportional-integral (PI) controller and current limiter. When the output of the speed PI controller is limited by the current limiter, a windup phenomenon and unstable response often occur. This paper proposes a new anti-windup control for the speed control system of an AC servomotor. In the conventional method, when the output of the speed PI controller is limited by a current limiter, the input of the integrator is revised by using the difference between the input and output of the limiter. In the proposed method, the input of the integrator is revised by considering an accelerating torque component. This allows the output of the integrator to converge to the torque current corresponding to the load torque. As a result, speed overshooting is suppressed, and a good transient response is provided. Furthermore, using a weight function to revise the input of the integrator can further suppress overshooting. The effectiveness of the proposed anti-windup control method was verified through experiments and numerical simulation.