Current Stress Optimization and Efficiency Increase of DAB with Triple-Phase-Shift Control Based on 2-Dimensional Ergodicity Method

Finding the method to maximize the potential of current stress reducing and system efficiency increasing is one of the most interesting and significant topics when TPS control is utilized in DAB. Correct classification of different operating models is an essential basic work, and the TPS method with bidirectional power flow is classified into 12 models on the basis of voltage decoupling of primary and secondary H-bridges in this paper. The transmission power and current stress expressions are fully derived with arbitrary combination of three phase-shift control freedoms for the whole operating range. A 2-dimensional ergodicity method is proposed in this paper to find the best combination of the two inner phase-shift ratios, which is expected to achieve the minimized current stress and increased system efficiency. The theoretical optimized results for different power and voltage conversion ratio is given in the paper with comparison of SPS control. Experiments are implemented on laboratory prototype, the current stress expressions and the effectiveness of ergodicity method are proved by experimental results.