Study on power losses of the full soft-switching current-fed DC/DC converter with Si and GaN devices

This paper discusses power losses in a current-fed DC/DC converter aimed for photovoltaic applications. Scenarios of the low voltage switch realization analyzed include a transistor with a series diode and two transistors in series. Both the high and the low voltage stage are designed with Si MOSFETs and GaN HEMTs to verify advantages of the new material in these applications. Semiconductor devices operate at soft-switching conditions, thus the study is focused on conduction and driving power losses. It appears from our calculations that GaN HEMTs show efficiency improvement of the soft-switching converter. Available GaN HEMTs belongs to the first generation of the commercially available devices. Future development of the GaN technology can greatly improve characteristics of the devices, which will result in superior performance over that of the Si.