Application of HESS for PV system with modified control strategy

In this paper, a new control strategy is proposed for PV based DC grid system with battery and supercapacitor as a hybrid energy storage system (HESS). To complement the supply demand mismatches in a PV energy based system a hybrid energy storage system consisting of battery and supercapacitor (SC) is generally used. The traditional control approach for HESS uses the high/low pass filter (HPF/LPF) method for system net power decomposition and HESS power dispatch. But due to the slow dynamics of the battery this can create a voltage imbalance problem in the system. We refine a conventional control strategy and propose a new control strategy with the utilization of uncompensated power from the batteries to increase the performance of overall HESS system. Thus, we reduce the stress in the batteries during larger power fluctuations which increase life of the battery. The effectiveness of proposed scheme is shown by simulation studies in MATLAB/SIMULINK.