A Family of Soft-Switching DC-DC Converters with Two Degrees of Freedom

Switching losses including reverse recovery losses, have a significant impact on total losses of DC-DC converters especially in high voltage applications. This article introduces a new family of DC-DC converters with two degrees of freedom, which can handle the mentioned issue. The proposed family of DC-DC converters contains a bidirectional and a unidirectional cell, and provides an additional control parameter. This parameter can be adjusted so that there are soft switching conditions for all the switches of the converter within the entire range of loading. In addition, properly tuning the new parameter can decrease the circulating current and consequently decrease the conduction losses considerably. Besides, the unidirectional cell contributes to power transfer, especially under full load condition. Moreover, the filter capacitor is one fourth in comparison with the conventional dc-dc converters. The proposed converter is modeled and its operation modes are studied. Also, in order to verify the findings, a 500 W prototype with a frequency of 100 kHz is implemented, and the results are compared.