Design of anti-windup compensator for superconducting magnetic energy storage

Actuator saturation is a ubiquitous phenomenon when the outputs of controllers reach the actuators´ limits, and then the dynamic performances become worse. In this paper, an anti-windup compensator (AWC) is designed for the controller of the superconducting magnetic energy storage (SMES) system to increase power system stability. First, power system with actuator saturation is modeled 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 traditional controller with a new one, this paper makes 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.