An Improved Resonant Dead-Time Model of DAB Converter Based on Extended-Phase-Shift Control

Dual active bridge (DAB) converters have the advantages of bidirectional power transmission and easy achievement of soft switching. For DAB converters, dead time is necessary to avoid short circuit and realize zero-voltage switching (ZVS). With the increasing demand of high power density of converters, the switching frequency is becoming higher and higher, and the ratio of dead time is larger and larger. Therefore, dead time effects including EMI aggravation and power transmission model deviation cannot be neglected. In this paper, dead-time effects of DAB converters based on extended-phase shift control are analyzed in detail. An improved analysis model considering parasitic capacitors and magnetizing inductor is proposed to explain the resonant dead-time effects and refine the previous theory. To verify correctness of theoretical analysis, a prototype with 250W rated output power and 100kHz switching frequency is built. The experimental results are consistent with the analysis.