Hybrid T-Type ZVS Pulsewidth Modulation DC–DC Converter

An isolated soft-switching dc–dc converter based on the
t
-type commutation cell and employing capacitive output filter is introduced in this article. A hybrid switching strategy is proposed, allowing the circuit to operate with a three- or four-level scheme relying on a unique duty cycle definition. The energy transfer process regarding two distinct continuous conduction modes is detailed and a complete static model is derived. Also, the requirements for the occurrence of zero voltage switching (ZVS) on the switches are evaluated, and a small-signal analysis is carried out to provide information on the dynamic behavior of the proposed circuit. The operation of the proposed converter is verified for the conditions of fixed input and output voltage and of wide input voltage range designs. Laboratory tests with a 1.2 kW prototype operating in closed-loop demonstrate the feasibility of the proposed circuit and validate the theoretical analysis carried out.