Efficiency Evaluation for DAB Converter with Reactive Power Minimization Strategy and Full ZVS Operation

It is usually believed that minimizing the reactive power while maintaining the zero voltage switching (ZVS) may significantly improve the efficiency of the dual active bridge (DAB) DC-DC converters. In this paper, the reactive power and soft switching characteristics of DAB with dual-phase-shifting (DPS) are analyzed. Therefore, a global optimal control (GOC) algorithm to minimize the reactive power while maintaining full ZVS operation is proposed. The experimental verification is carried out on the 1.5 kW prototype and the efficiency is compared with single-phase-shifting (SPS). However, the experimental results show that the efficiency at light load is lower than SPS. Furthermore, a reactive power optimization control without ZVS constraints was also performed for comparison. Finally, the efficiency is evaluated for the DAB converters with reactive power minimization and ZVS.