Energy conversion efficiency of single-phase transformerless PV inverters

In grid-connected photovoltaic (PV) applications, power semiconductor energy conversion efficiency of PV inverters is one of the major figures of merits to evaluate and compare these systems as the payback ratio of the overall system is tightly related to the energy conversion efficiency and as semiconductor losses comprise the majority of energy losses. In order to wisely choose the PV inverter topology and associated semiconductors, analytic evaluation of semiconductor losses of topologies is required. Furthermore, the evaluation of these losses serves the purpose of designing PV inverters in terms of better thermal management and reliability. In this study, the analytical semiconductor efficiency evaluation of PV inverters promising high efficiency is performed for 3 kW and 10 kW power ratings based on selected semiconductor datasheets and average power per switching cycle (APPSC) method. A comparison of energy efficiency of topologies regarding power levels is provided.