PV energy extraction characteristic study under shading conditions for different converter configurations

A solar photovoltaic (PV) energy conversion system requires power converters for maximum power extraction and grid integration. At present, typical converter configurations used in a solar PV system include central, string and micro converter based PV systems. In order to develop efficient and reliable energy conversion technologies, this paper compares the energy extraction characteristics of a PV system for different converter configurations. The paper particularly focuses on how energy extraction characteristics of a PV array are affected by uneven shadings. The paper also proposes bypass diode arrangements for PV modules and arrays. A detailed comparison study is conducted to investigate what are enhancements and impacts by using different bypass diode schemes. It is found that compared to micro-converter based PV systems, the central converter scheme with effective bypass diode connections could be a simple and economic solution to significantly enhance PV system efficiency, reliability and performance.