Triple-Phase Shift Modulation and Tuning Technique to Improve the Efficiency of the Dual Active Bridge Converter

This paper proposes a triple phase shift modulation with an optimization technique that aims at maximizing the efficiency of the Dual Active Bridge (DAB) converter. The DAB converter finds application in smart dc power systems, including the electrification of the powertrain of vehicles and vehicles-to-grid applications, where loss minimization is crucial. In this paper, favorable modulation parameters are found first, by aiming at minimum rms currents and zero voltage switching (ZVS) for the converter switches. Then, on the basis of the closed-form analytical description of the converter behavior over the determined favorable modulation patterns, efficiency improvement trajectories in the modulation planes are identified. It is shown that such trajectories lead to optimal efficiency operation, which can be exploited to implement fast closed-loop efficiency optimization methods. The reported results are verified experimentally on a 1.5 kW prototype, showing that the proposed approach allows to achieve the best-efficiency operation of the converter.