A novel non-isolated bidirectional DC-DC converter for high voltage gain applications

Abstract

The voltage gain of conventional non-isolated dc-dc converters like the boost converter is limited due to capacitor discharge at near unity duty cycles. Most non-isolated converters can provide a practical gain of around 4. This paper presents a non-isolated bidirectional converter which is capable of providing significantly high gains when operated at duty ratios close to 0.5. The proposed converter topology employs a H bridge configuration with four bidirectional switches. The operation of the proposed converter involves 4 power devices, a single filter inductor and output capacitor. Detailed operation of the converter considering factors such as non-idealities and efficiency is presented in this paper. Digital controller is designed using root locus technique for closed loop operation of the proposed converter. For a given efficiency, the proposed converter achieves better voltage gain (15–20) compared to the existing high gain converters. A MATLAB simulation study is carried to validate the analysis and operation of the converter. Finally, comparison of the proposed converter with the conventional boost converter in terms of gain and efficiency is also presented.