A Dual DC Output Power Supply for a Stand-alone Photovoltaic System

摘要

This article presents a dual DC power output for easy integration of renewable energy sources and battery banks at a low-voltage DC bus. The low-voltage loads are connected to the low-voltage DC bus directly (across the battery banks), obviating an additional conversion stage. Such low-voltage loads are LED-based lighting, computers, laptop chargers, etc. The proposed system consists of a photovoltaic array, DC-DC converters, a maximum power point tracker, and a storage medium (battery) targeted for low-voltage (24 V) and high-voltage (110 V) DC loads. The maximum value of photovoltaic power is extracted using the buck DC-DC converter along with the effective incremental conductance maximum power point tracking technique to control the power transfer to the low-voltage DC grid. The DC-DC boost converter is designed to operate at a constant voltage of 110 V DC load. The proportional-integral-derivative control parameters for voltage mode closed-loop control of the boost converter are chosen by using the genetic algorithm technique. A prototype system has been built in the laboratory, and its satisfactory working has been demonstrated experimentally for the different shading and loading conditions; experimental results are provided.