Current Stress Optimisation Strategy for Three-phase Dual Active Bridge Converter during the Start-Up Process

Abstract

Three-phase dual active bridge (3p-DAB) converter is widely used in high-power bidirectional power transfer applications, due to its unique high power density and easy implementation of soft switching. In this paper, the start-up process of the 3p-DAB converter is studied. The cause of high current stress, especially in the case of heavy-load start-up is analysed, and a new start-up control strategy for the start-up process is proposed. The control strategy is helpful to reduce the current stress of the transformer and the switches by adjusting the duty-cycle and the phase shift angle coordinately without adding any other hardware circuits. Finally, based on a TMS320F28377D + XC6SLX25 controller, a 30kW 3p-DAB converter prototype with input voltage 650-750V and output voltage 400-500V is developed to verify the effectiveness of the proposed start-up strategy.