Dead-time effect analysis of dual active bridge DC-DC converter with dual-phase-shift control

This paper gives a detailed analysis about the causes of the voltage distortion caused by dead time in dual active bridge (DAB) DC-DC converter. The zero-crossing point of the equivalent leakage inductor's current is the definitive factor for various voltage distortion phenomena, which is determined by dead time and phase-shift ratios. Based on the switching characterization of DAB in dual-phase-shift scheme, a comprehensive summary of dead-time effect is acquired, including voltage polarity reversal, voltage sag and duty-cycle abnormity. At the same time, the causes of these phenomena are analyzed in detail. Considering all kinds of voltage distortion phenomena will affect the transmission power and other issues, a special operation mode defined as recessive-dead-time mode is obtained. In recessive-dead-time mode, the dead-time effect can be avoided by reasonable parameter-setting, thus, the voltage distortion will not occur. Finally, experimental results verify the theoretical analysis.