Control Strategy of Grid-Side Converter for Flywheel Energy Storage System under Grid Asymmetrical Faults

Flywheel Energy Storage System (FESS) is a high dynamic response power energy storage. When an asymmetrical fault occurs in the grid-integrated point voltage of FESS, the DC side of the Grid-Side Converter (GSC) using the traditional double-loop control strategy, are contained with even-numbered harmonics which can seriously affect the quality of output of the GSC. In this paper, a control strategy of the GSC for FESS under asymmetrical faults is proposed. The control strategy can suppress the secondary fluctuations of the output active power and DC bus voltage, and limit the current amplitude of the GSC. Finally, the effectiveness of the control strategy is verified by building a grid-integrated model of the flywheel energy storage GSC on Matlab/Simulink.