Coordination of a Flywheel Energy Storage Matrix System: An External Model Approach

This paper studies the coordination of a heterogenous flywheel energy storage matrix system aiming at simultaneous reference power tracking and state-of-energy balancing. It is first revealed that this problem is solvable if and only if the state-of-energy of all the flywheel systems synchronize to a common time-varying manifold governed by a nonautonomous dynamic system. Next, by treating this nonautonomous dynamic system as an external model, the coordination problem can be decoupled into two separate problems, namely, the global double layer estimation problem and the local tracking problem. Then, a distributed control scheme is proposed to solve the coordination problem by integrating the adaptive distributed observer approach and the certainty equivalence control method. Comprehensive case studies are provided to show the performance of the proposed control scheme.