Terminal voltage analysis for the transformerless PV inverter topologies in a single‐phase system

Abstract

This study presents an analysis of the terminal voltage of the basic photovoltaic (PV) inverter topologies available in the literature. The presented analysis utilises the switching function concept. Use of switching function in the analysis enables the inclusion of the effect of the pulse‐width modulation technique or the switching strategy on the terminal voltage of the reviewed configuration. It gives insight into the switching action effects on the terminal voltage and provides every detail of the high‐frequency transitions in the terminal voltage for the given switching strategy. Using the terminal voltage expression derived in terms of switching function, the analytical waveforms are obtained for various configurations. These waveforms are compared with the simulation and experimental results waveforms to justify the analysis given. This study also presents a bar chart view of the switching and conduction losses of the switches in the reviewed PV inverter topologies. The magnitude of high‐frequency components in the terminal voltage and the leakage current is also presented in this study. The PV inverter topologies are also compared in terms of other aspects such as a number of devices used, asymmetry in operation, filter requirement etc.