Fully Soft Switched Nonisolated High Step-Up Single Magnetic Core Multiport Converter With Reduced Voltage Stress

Abstract

This article presents a fully soft switched, nonisolated high voltage gain single magnetic core multiport converter based on boost three port structure for renewable energy applications. The developed voltage multiplier cell integrates switched capacitor and coupled inductors techniques to achieve high voltage gain and more design freedom. Furthermore, only a single magnetic core is employed which contributes to higher power density while an active clamp cell is integrated to provide fully soft switching condition and eliminate capacitive turn-on loss. All switches operate at zero voltage switching and diodes turn off at zero current switching. This approach minimizes switching losses and clamps the voltage spikes which enables the use of low forward voltage diodes. Also, the switches voltage stress is reduced through utilizing coupled inductors technique and thus, switches with low drain-source resistance can be utilized to achieve high efficiency along with high power density. To validate the theoretical analysis, a 200 W prototype with 400 V output port is implemented and the experimental results are presented.