A Dual-Transformer-Based Bidirectional DC–DC Converter of Using Blocking Capacitor for Wide ZVS Range
Yanke Liang, Xu Liu, Guokai Xu, Shuaichao Yue
Abstract
In order to improve the efficiency of battery charging and discharging in a wide conversion gain, a dual-transformer-based full bridge converter using a block capacitor was proposed. By adding the blocking capacitor in the primary side of one transformer, an extended zero voltage switching (ZVS) range is obtained in a wide output voltage range, which is achieved by regulating the secondary voltage of the transformers to match the output voltage according to the voltage-second balance in both boost and buck modes. Besides, a mirror-symmetrical modulation is introduced in reverse power flow to avoid a limited ZVS range of the traditional dual-transformer converter. The power characteristics and ZVS range are analyzed in detailed. The analysis results and transformer current are compared with the published dual-transformer converter and the conventional dual active bridge (DAB) converter to demonstrate the advantages. Finally, a 300W prototype was built and tested to verify the effectiveness of the proposed converter.