Solar Energy, Vol.125, 180-191, 2016
A hybrid grid connected PV battery energy storage system with power quality improvement
In this paper, fast acting dc-link voltage-based energy management schemes are proposed for a hybrid energy storage system fed by solar photovoltaic (PV) energy. Fast dc-link voltage, effective energy management, and reduced current stress on battery are the main features achieved from the proposed control schemes. The main features obtained from the proposed control schemes are tight dc-link voltage regulation, effective power management at the dc-link, allows current limits for both the battery and the supercapacitor. The effectiveness of the proposed control schemes are compared with the unified cascaded control. Using the proposed control schemes, quick fluctuations of load are supplied by the super capacitors and the average load demand is controlled by the batteries. Small-signal control gains are formulated to design the voltage and current loops of the proposed energy management schemes. Detailed stability analysis is also presented to find the boundary values of compensator gains. In addition, a high-gain PV converter is proposed for extraction of maximum power from the solar panels. High voltage gain, reduced reverse recovery of diodes, and less duty cycle operation are the key features obtained from the proposed high-gain converter. The validity of the proposed energy management schemes with high gain converter is verified by the detailed simulation and experimental studies. (C) 2015 Elsevier Ltd. All rights reserved.
Keywords:Battery;Dynamic energy management;Photovoltaic (PV) system;Small-signal models;Supercapacitor