Loads adaptive input-series-output-parallel phase shift full bridge derived DC-DC converters with auxiliary LC networks to achieve wide zero voltage switching range

An input-series-output-parallel (ISOP) two phase shift full bridge DC-DC converters with two auxiliary LC networks was proposed. Each LC network is connected between the leading-leg mid-point of a module and the lagging-leg mid-point of the other one. With the aid of the LC networks even at light loads, ZVS for lagging-leg switches can be achieved, and the current amplitude of LC networks are load adaptive. i. e., at light loads, the energy used to achieve soft switching for lagging leg switches increases and the circulating current and its loss is reduced. Thus, it is very suitable for wide load range. The feature of the converter is analyzed. The performance of the proposed converter is verified by a 900W experimental prototype.