RESIDENTIAL PHOTOVOLTAIC ENERGY-STORAGE SYSTEM

This paper introduces a residential photovoitaic (PV) energy storage s ystem, in which the PV power is controlled by a dc-dc converter and tr ansferred to a small battery energy storage system (BESS), For managin g the power, a pattern of daily operation considering the load charact eristic of the homeowner, the generation characteristic of the PV powe r, and the power-leveling demand of the utility is prescribed. The sys tem looks up the pattern to select the operation mode, so that powers from the PV array, the batteries, and the utility are utilized in a co st-effective manner. As for the control of the system, a novel control technique for the maximum power-point tracking (MPPT) of the PV array is proposed, in which the state-averaged model of the dc-dc converter , including the dynamic model of the PV array, is derived, Accordingly , a high-performance discrete MPPT controller that tracks the maximum power point with zero-slope regulation and current-mode control is pre sented. With proposed arrangements on the control of the BESS and the current-to-power scaling factor setting, the dc-dc converter is capabl e of combining with the BESS for performing the functions of power con ditioning and active power filtering. An experimental 600-W system is implemented, and some simulation and experimental results are provided to demonstrate the effectiveness of the proposed system.