A topology review and comparative analysis on transformerless grid-connected photovoltaic inverters and leakage current reduction techniques

Photovoltaic energy source growth is significant in power generation field. Moreover, grid connected inverters strengthen this growth. Development of transformerless inverters with higher efficiency, low cost and size is competitive than the inverters with transformers. However, leakage current generation in transformerless inverters is a challenge to their growth. The research in evolution of new transformerless inverter topologies with higher efficiency, boosting capability, and reduced leakage current is interesting. This paper presents an extensive discussion of transformerless inverters under the categorization of their structures and the subcategorization with leakage current reduction techniques. The components and connections of inverters are differentiated with colours for the effortless understanding of operation. The detailed comparisons of transformerless inverters based on performance and construction are also presented with their strengths and weaknesses. To give deep intuition on characteristics of transformerless inverters, selected inverters are simulated with different operating conditions. Loss contribution of each switch in the selected inverters is analysed, to help the new researchers, designers and engineers to design efficient topologies. © 2022 The Authors. IET Renewable Power Generation published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology.