Abstract:
For the problem of system frequency and voltage fluctuations caused by the switching of grid-connected and off-grid modes, the mutation of micro-source and the disturbance of load conditions, the self-recovery droop control strategy of frequency and voltage is proposed. Firstly, the self-recovery droop control model of energy storage unit is established based on the traditional droop control by introducing frequency difference and voltage difference as feedback links. Secondly, the performance of self-recovery and traditional droop control coefficients are compared and analyzed in different frequency bands by Bode diagram. The self-recovery droop control has better effect of system frequency and voltage self-recovery due to the adopting of PI control and the introduction of correction droop coefficient factors, which improves the dynamic adjustment capability and shows better adaptability. Finally, a 35 kV wind-solar-storage microgrid model is established based on Matlab/Simulink, and the effectiveness of the self-recovery droop control strategy is verified by time-domain simulation experiments.