Novel Control of Dual-Grounded Soft-Switching Transformerless Single-Phase Inverter

A high-efficiency dual-grounded soft-switching transformerless single-phase inverter is proposed in this article. It is able to achieve the zero-voltage switching (ZVS) and inherent leakage current reduction. A control method based on digital frequency calculation is applied to the inverter to achieve the ZVS operation. Based on this control method, no additional circuits and components are required, and it has the advantages of simple adjustment, high reliability, and low cost. Also, a digital calculation method for the bias current of ZVS is proposed for implementing the real-time programmable control. Finally, the proposed method is tested on a digital experimental platform. The efficiency of the inverter with the proposed and conventional methods under different loads is tested and compared. The experimental results show that the efficiency can be improved from 96.39% to 98.4% at rating load.