High Gain Isolated Quasi-Switched Boost Converter Embedded with Switched Capacitor Cell

Abstract

—A DC–DC converter that can deliver high gain and isolation using quasi-switched boost and switched capacitor cell (qSB-SC) is proposed. This converter is well suited for renewable energy applications, where generally, low voltage input sources are available. The converter circuit presented in this work consists of four stages. The first stage comprises a quasi-switched boost network with an inductor. A SC cell is embedded in the second stage that can further boost the voltage. The third stage has a push-pull converter with a high-frequency transformer. In the fourth stage, there is a voltage doubler rectifier circuit which again enhances the boost capability. Detailed analysis pertaining to selection of circuit elements used in the converter is also derived. The proposed converter is compared with few state-of-the-art competitive topologies to prove its high boost ability. A 250 W prototype of the proposed converter is realized with an output voltage of 400 V when fed from a 30 V input source. The results obtained concur well with the simulated and theoretical results. The merits of the converter are (i) continuous ripple-free source and load current, (ii) galvanic isolation, and (iii) very high gain.