Optimum design and analysis of a dynamic energy management scheme for HESS in renewable power generation applications

Abstract

A novel control strategy for a hybrid energy storage system (HESS) is outlined and examined in this paper. In the proposed system, the battery is utilized to stabilize the moderate changing of power surges, whereas supercapacitor is utilized to stabilize the rapidly changing of power surges. A two-loop proportional-integral controller is designed for the closed-loop operation of HESS. The source power and load power is not balanced because of the fluctuating conditions of photovoltaic (PV) power generation and load demand. This power imbalance causes fluctuations in direct current (DC) grid voltage. The DC bus voltage variations are mitigated using HESS, which is connected to DC grid through bi-directional DC–DC converter to enables the bidirectional power flow between energy storage devices and the DC bus. To enhance the life span and to reduce the current stress on the battery, the proposed method is employed with charge/discharge rate control feature. The proposed control procedure is realized in MATLAB/Simulink and the results are presented for different case studies. Experimental results are obtained for a two-input bi-directional converter at the sudden change in PV generation and load demand with the proposed controller. The proposed control strategy is effective for maintaining constant DC microgrid voltage under source and load fluctuations.