Second order adaptive notch filter based wind power smoothing using flywheel energy storage system

Smoothing wind power is a vital process to allow increasing wind integration into the grid. This paper proposes a control strategy to smooth wind power by using flywheel energy storage system (FESS) driven by permanent magnet synchronous machine (PMSM). A back-to-back converter is used to connect the flywheel system with the grid. The converter functions are to control the charging/discharging process of the flywheel, to keep the DC link voltage at constant predetermined value, and to control the reactive power exchanged with the grid. The second order adaptive notch filter (SOANF) is proposed to estimate the flywheel power reference by filtering the wind power. The dynamic performance of the proposed control strategy is studied using PSCAD/EMTDC software. The simulation results proved the success of the proposed control in smoothing wind power. They also show acceptable behavior of the proposed filtering technique and the strength of the proposed control strategy.