Bi-directional power control for flywheel energy storage system with vector-controlled induction machine drive

Short-term energy storage devices with excellent cycling capabilities are highly desirable for use in conjunction with renewable energy resources such as wind and wave power systems. The paper presents a flywheel energy storage system based on a vector-controlled induction machine drive with bidirectional power control. A description of the power electronic drive and of the development aspects for adding fast-response active and reactive power controllers are given. Integration of the flywheel drive into the power system at the Rutherford Appleton Laboratory (RAL) Wind Test Site (WTS), is also described with the dynamic/supervisory controller explained. Practical results obtained via the dynamic controller and the instrumentation facilities at the WTS, demonstrating the time and frequency responses of the flywheel drive and those obtained from implementing the system with wind power smoothing configuration, are presented and discussed