Design of Anti-windup Compensator for Superconducting Magnetic Energy Storage

Actuator saturation is a common phenomenon to degrade the dynamic performance of a control system because of discordance of output of controller and actuator. It happens when the outputs of controllers reach their limits, and then the dynamic performances become worse. In this paper, an anti-windup compensator (AWC) is applied to the controller of the superconducting magnetic energy storage (SMES) system to improve power system stability. First, power system with actuator saturation is described to formulate the problem mathematically. Then, uniform anti-windup scheme is studied and compensator is designed with method of linear matrix inequality (LMI). Instead of replacing the original controller with a new one, the anti-windup compensation make use of the difference between the controller’s and the actuator’s output to mitigate the adverse influence of saturation, which leaves the original controller unaffected. Hence, this method can be used to enhance power system stability under the same capacity with its unsaturated controller so that SMES is utilized more efficiently.