Dual-Transformer-Based DAB Converter with Wide ZVS Range for Wide Voltage Gain Application
Dual-transformer-based dual active bridge (DAB) converter with wide ZVS range for wide voltage conversion gain application is derived and studied in this chapter. The phase shift control is adopted for this converter with minimum power switches employing half-bridge output, and a control law is proposed to achieve wide ZVS range. With the proposed method, four switches of the converter can achieve full range of ZVS. The other two switches can achieve full-range ZVS under positive power flow, while slightly reduced ZVS region under reverse power flow. Unlike the methods employing three control degrees of freedom, the proposed method only utilizes two decoupled control variables, making the controller easy to be implemented. In addition, the design of turns ratios for the two transformers under the proposed control is also optimized based on the gain ranges and conduction loss. The effectiveness of the converter with the proposed control is verified by experimental results from a 1 kW prototype.
KeywordsDual-transformer-based Dual active bridge converter Wide ZVS range Wide conversion gain