Research on Modelling and Stability Characteristics of Electric Traffic Energy System Based on ZVS-DAB Converter

We study and describe mostly used traditional simplified circuits for full-bridge Zero Voltage Switching-Dual Active Bridge (ZVS-DAB) converter and deduce their mathematical model. On this basis, we propose a high-frequency (HF) mathematical model, which takes into account conduction loss and HF characteristics of the ZVS-DAB converter model. We compare the static and dynamic stabilities of the traditional and the proposed HF mathematical model by simulation. Finally, the high-frequency planar transformer (HFPT) with good heat dissipation and the wide band gap (WBG) semiconductor SiC switches with fast switching speed are employed to build a 4.4 kw, 40 KHz experimental prototype to verify the effectiveness of the improved HF circuit of ZVS-DAB converter. The results show that the proposed HF mathematical model is superior to the traditional one, and it fully considers the HF characteristics of the circuit and effectively improves the HF oscillation, DC bias, and waveform distortion of the ZVS-DAB converter.