Transformerless Capacitively Isolated DC/DC Current Source Converter

In recent years, significant resources have been invested by both the research community and industry in the study and development of isolated DC/DC converters for interfacing renewable energy sources and storage systems. In this context, the electrical isolation between different stages of the system is a mandatory requirement for several applications. This study investigated a novel isolated DC/DC current source converter with capacitive isolation. The proposed solution consists of two bridges, each one realized using four reverse-blocking switches, interfaced through two isolation capacitors, and a shunt high frequency capacitor allowing power to be transferred between the two DC sides. The converter structure, operating principles, and component sizing requirements were first analyzed. Then, simulations were performed using MATLAB/Simulink© and LTSpice© to demonstrate the operation of a 10 kW converter, which confirmed the results of a theoretical analysis. Experimental tests were also conducted on a scaled prototype.