A High-Efficiency Bidirectional LLC Resonant Converter Based on Current-Doubler Rectification Circuit

With the development of microgrids, DC/DC converters for bidirectional energy transmission between DC bus and energy storage batteries have received more and more attention. In order to convert the high voltage of the DC bus and the low voltage of the batteries, the converters with high-ratio transformers are widely used. However, high transformation ratio brings large secondary winding current, which causes large loss. To improve this defect, the current-doubler rectifier circuit and the LLC resonant converter is combined to build a new bidirectional DC/DC converter. The proposed topology not only reduces the secondary winding current but also reduces the number of MOSFETs, thus improving the efficiency of the converter. The working principle of the proposed converter is introduced, and the problem of voltage spikes in reverse operation is solved by means of ideally inverse coupled inductors. Through comparison and analysis, the feasibility of the proposed topology is verified and the results show that the proposed converter has higher efficiency than the traditional bidirectional LLC converter.