A Family of Cuk, Zeta, and SEPIC Based Soft-Switching DC-DC Converters

In this paper, a new class of dc-dc converter topologies based on capacitive link dc-dc converters-Cuk, SEPIC, and Zeta converters-that operate under the critical conduction mode has been proposed. The proposed converters are the extensions of quasi-square-wave zero-current-switching converters, which use an auxiliary circuit to provide zero-current and zero-voltage switching for all semiconductor switches at both turn ON and turn OFF transitions and eliminate voltage ringing across the output switch. Using the proposed auxiliary circuit, the value of dv/dt has been diminished; hence, the EMI of the proposed topology is significantly reduced compared to the conventional quasi-squarewave zero-current-switching converters. To verify the operation of the proposed converter and confirm its advantages, an experimental prototype has been implemented, and the experimental results and the efficiency of the proposed converter have been compared with the conventional quasi-square-wave zero-current-switching converters.