Optimal Dead-Time Design Method Based on Single-Side Asymmetrical Duty Modulation for DAB-Based Energy Storage System

With the rapid development of energy storage system, dual-active-bridge (DAB) circuit has become a popular interface circuit for its advantages of high-power density, strong bidirectional transmission capability and simple control scheme. Compared with traditional modulation methods, a single-sided asymmetric modulation (SSAM) is proposed to widen the soft switching region and reduce the current level. In order to improve the efficiency, the dead-time optimization method is proposed by analyzing the relationship between the dead-time $t_{\text{db}}$ , junction capacitance $C_{\text{oss}}$ , current value $I_{\text{sw}}$ at turn-off time, inductance value $L$ and voltage gains. Therefore, a detailed dead zone design is carried out and the dead zone range can be estimated. By comparing the existing modulation schemes, the proposed SSAM can achieve the widest ZVS range. Finally, a dab based prototype is established to verify the effectiveness and correctness of the proposed method.