Research on Control Method for Flywheel Battery Energy Storage System

This paper presents a new control method for the flywheel battery energy storage (FBES) system. The proposed method adopts a double closed-loop control structure, which is based on an outer DC bus voltage loop cascaded with an inner current loop, and has an additional speed control loop. It can achieve charge and discharge process of the flywheel battery through regulating the flywheel speed without changing the outer loop control object. During the charge process, the DC bus voltage is completely determined by power system and the speed control loop limits the flywheel speed to avoid overcharge. Accordingly, the stability of the DC bus voltage is maintained by the flywheel battery during the discharge process. A FBES system is established with Matlab/Simulink to complete the charge and discharge control simulation and the sudden loading simulation during discharge. Meanwhile correlative experiments on a flywheel battery prototype are conducted. Simulation and experimental results verify the effectiveness of the proposed method.