Hybrid Energy Storage System with Doubly Fed Flywheel and Coordination Control Strategy

Doubly fed flywheel has fast charging and discharging response speed and long cycle life. It can form a hybrid energy storage system with lithium batteries, complement each other's advantages, and jointly suppress the fluctuation of new energy generation. This paper studies the structure and coordination control strategy of hybrid energy storage system with doubly fed flywheel and battery. Firstly, the simulation model of AC hybrid energy storage microgrid is built, and a coordinated control strategies of hybrid energy storage system is proposed and simulated for grid connected operation mode and isolated island operation mode. In this strategy, the power response delay of lithium battery is considered and the integrated inertia control is introduced. The research results show that after the microgrid is introduced into the doubly fed flywheel energy storage system, the doubly fed flywheel energy storage can effectively reduce the power fluctuation of the connection point under the grid connected operation mode. And it can effectively reduce the power impact of the battery at the moment of power shortage, slow down the aging of the battery and prolong the service life, reduce the frequency fluctuation of the microgrid, slow down the frequency deterioration, and improve the stability of the microgrid operation under the isolated island operation mode.