Evaluation of Grid-Connected PV Converter Power Module Technologies in Terms of Efficiency, Initial Cost, and Return on Investment Time

Abstract

The voltage source converter (VSC) of the grid connected photovoltaic (PV) systems is the most technological component in a PV system and contributes to 5-15% of the whole investment. As the cost and energy efficiency of a VSC are two factors that determine the total system economics, the system total cost of ownership (TCO) should be optimized during the VSC design. This paper provides a design methodology for grid connected VSCs considering TCO, the return on investment (ROI) and payback period (PP) as the basic criterion for optimization. In the design, since power electronics is entering the wide-bandgap device technology age, higher efficiency and faster wide bandgap devices are also weighed along with the silicon IGBT (Si-IGBT) technology. In the paper, the power module, passives (LCL filter) and heatsink are designed and compared with the conventional design as reference. The comparative and progressive design study of a 1-MW PV power plant with 30-kW string PV converters demonstrates the advantages of design with wide bandgap devices. The investigation is conveyed via theory, analytical methods, and experiments.