Modeling and Control of Flywheel Energy Storage System

Flywheel energy storage has the advantages of fast response speed and high energy storage density, and long service life, etc, therefore it has broad application prospects for the power grid with high share of renewable energy generation, such as participating grid frequency regulation, smoothing renewable energy generation fluctuation, etc. In this paper, a grid-connected operation structure of flywheel energy storage system (FESS) based on permanent magnet synchronous motor (PMSM) is designed, and the mathematical model of the system is established. Then, for typical operation scenarios such as normal operation and three-phase short-circuit fault of 35 kV AC bus, the grid-connected operation control method and fault ride through control strategy of the system are proposed. In the normal operation scenario, the unit factor operation of the energy storage system is realized by controlling the grid-side converter. In the three-phase short-circuit fault scenario, the FESS voltage support capability is fully utilized by switching the converter control mode. Finally, the simulation model of FESS is built by RTDS simulation platform. The simulation results verify the effectiveness of the proposed control strategy.