Frequency Control Strategy of Hybrid Energy Storage System for Microgrid Based on Frequency Hysteretic Loop

In this paper, a frequency control strategy of hybrid energy storage system (HESS) for autonomous microgrid (AMG) based on a frequency hysteretic loop is proposed. The control strategy is composed of two modes. Mode I coordinates the relationship between the frequency control precision and the battery charge/discharge cycles. Mode II coordinates the charge/discharge priorities of battery and supercapacitor to achieve the optimal control of different energy storage systems. Finally, a test system is established to verify the effectiveness of the proposed frequency hysteretic loop based control strategy of HESS. The proposed frequency control strategy can make significant contribution to the stable operation of MG and promote the utilization level of renewable energy resources.