Adaptive comprehensive control strategy for primary frequency regulation of coal-fired units assisted by flywheel energy storage system

To improve the flywheel energy storage system (FESS) assisting the primary frequency regulation (PFR) of coal-fired units, an adaptive comprehensive control strategy for PFR taking into account state of charge (SOC) self-recovery is proposed. The strategy introduces an adaptive frequency deviation coefficient so that it can adaptively adjust the inertia coefficient and droop coefficient according to the PFR depth and SOC. In the SOC self-recovery stage, the SOC self-recovery output strategy of the FESS is proposed, which improves the bidirectional adjustment performance of the FESS. Finally, the proposed control strategy is verified in Matlab/Simulink.