Short Time-scale Analysis of Dead-time Effect in Dual Active Half-Bridge Converter

In this paper, a dead-time effect is analyzed in a short-time scale for the dual active half-bridge (DAHB) converter. The dead-time causes ac voltage distortions between the bridges, which induces several practical issues such as voltage polarity reversal and phase drift. Thus, power flow characteristics are not only affected by a phase shift ratio and a voltage ratio but also distorted by a dead-time ratio. This paper analyzes operating waveforms of the DAHB converter in detail over one switching cycle. Moreover, power flow equations are derived from the operating waveforms where the dead-time effects of operation mode are included. These analyses clarify that the power flow equation cannot be modeled as a monotone increasing function, where a power plateau occurs. Lastly, the accuracy of the proposed power flow model is verified through simulation results.