Input-Parallel Output-Series High Step-Up DC/DC Converter With Coupled Inductor and Switched Capacitor

Abstract

In this study, the authors propose a non-isolated high step-up interleaved DC/DC converter that can be applied to sustainable energy system. The proposed converter achieves high voltage gain by employing a coupled inductor and switched capacitor method based on an interleaved boost converter. The two coupled inductors connected in parallel with the input side have a distinct structure. Specifically, a single coupled inductor has a primary side and a secondary side connected in series, and it is further connected in parallel with an output side switched capacitor circuit. The switched capacitor circuit increases the voltage gain by being charged in parallel and discharged in series through the coupled inductor. The leakage inductor energy of the coupled inductor can be regenerated to the output side through the passive clamp circuit's performance. Moreover, it is possible to select devices with low voltage stress and on-state resistance of the switches, which results in reduced loss and size while alleviating the reverse recovery problem of diodes. The steady-state analysis and operation principle of the proposed converter are thoroughly explained and verified through a prototype circuit with 20V input voltage, 400V output voltage, and 320W level output power.