An optimized battery charging system based on a modified MPPT strategy for isolated PV energy generation

This paper describes the development of a high power battery charging system optimized for photovoltaic (PV) isolated microgrids. The charger implements a modified Maximum Power Point Tracking (MPPT) strategy that is suitable for isolated photovoltaic applications with battery storage systems (BSS). The proposed strategy is able to extract maximum power when possible and controls the power delivered to the BSS in order to supply the maximum possible energy without overcharging the batteries, enabling the operation with other current sources battery chargers. The proposed system is first simulated in the MATLAB/Simulink environment and then implemented in a 35kW charge controller, based on ten paralleled buck converters, connected to a 120V 600Ah OPZv BSS. The system hardware is designed to be very reliable and to be operated at extreme ambient conditions.