Live Transitioning of two Series-Parallel-Output Dual Active Bridge Converters

MSc defense of Koen Linders

EV chargers need to supply a wide output voltage (150V-1000V) since battery voltages of 400V, 600V and 800V are all becoming more popular. In this thesis, a 25kW converter is proposed with two  DAB converters connected in series-parallel output. To achieve the highest efficiency in the full operating range, a novel method of reconfiguration is introduced to allow live transitioning between series and parallel modes. The efficiency of the converter is increased to >97.6% in the full operating range by applying TPS modulation with Triple Phase Shift (TPS) with Minimum Current Stress Optimization (MCSO). The 25kW converter is simulated in PLECS and the reconfiguration method is verified on a hardware prototype.