A Two-Switch Step-Up Topology With Coupled Inductor for High Voltage Conversion

Abstract

This paper introduces a new non–isolated boost–type dc–dc converter that is applicable to PV/fuel cell sources and other low–voltage dc systems requiring high voltage gain and a compact structure. The proposed architecture incorporates two synchronized switches, a coupled magnetic element, a passive energy recovery unit, and a multi–stage voltage elevating network to achieve a very high output voltage while minimizing component stress and maintaining a simple structure. A smooth input current profile with minimal ripple is ensured by the input inductor, and conduction losses are lowered through current distribution across the switching devices. The passive clamp design enables the recovery of leakage energy and limits overvoltage across power devices, permitting the employment of low–voltage–rated MOSFETs to enhance the overall efficiency. A staged voltage boosting technique further increases the output without significantly increasing circuit complexity. Compared to existing topologies, the proposed converter demonstrates advantages in voltage boosting capability, stress reduction on switches, and reduction in the overall part count. Theoretical analysis, design procedures, and performance comparisons are thoroughly discussed to validate the proposed design. A 200 W prototype operating from a 24 V input to a 400 V output was simulated and built. Simulation and test results match theoretical predictions, with peak efficiencies of 95.2% and 94.1% at full load, confirming the converter’s suitability for compact, high–efficiency power systems including PV microinverters, battery storage, EV auxiliary modules, marine power, medical devices, and high–voltage loads such as plasma generators and AMOLED displays.