Frequency Regulation Control Strategy for Combined Wind-Storage System Considering Full Wind Speed

Abstract

Energy storage (ES) has a flexible regulation performance to improve the frequency stability of the wind turbine system. However, the doubly-fed induction generator (DFIG) has different frequency regulation capabilities operating at different wind speeds, and how to collaborate the operation of DFIG with ES for frequency regulation is a very critical problem. A combined wind-storage frequency regulation control strategy considering full wind speed is proposed in this paper. Firstly, the equivalent model of the combined wind-storage system is established, and the virtual inertia control of DFIG and the droop control of ES are analyzed for the system frequency regulation. Secondly, propose the combined wind-storage frequency regulation control strategy based on the operation characteristics of the DFIG in different wind speed zones. At low wind speed, the frequency regulation capability of DFIG is fully considered, and ES is allowed to start first for frequency regulation. Improving frequency fluctuations at medium wind speeds using a combined wind-storage system operating in concert. In order to allow DFIG to operate safely at high wind speeds only frequency regulation is performed by ES. Finally, the effectiveness of the proposed strategy is verified by simulating the sudden increase of system load under different wind speed zones on MATLAB/Simulink platform. The results indicate that the strategy has better frequency regulation effect and effectively improves the stability of the system frequency.