Dual-active-bridge series resonant converter: A new control strategy using phase-shifting combined frequency modulation

This paper proposes a new control strategy for a single phase isolated-dual-active-bridge series resonant converter (IDBRC). The proposed strategy combines both frequency modulation and phase shifting between the two active bridges. The shifted phase is kept at a suitable value to maximize the average power factor of the system and to handle the direction of the power flow. Meanwhile, frequency modulation is used to manipulate the magnitude of the power to be transferred. By using the proposed control method, both the active bridges can achieve zero voltage transition feature. System efficiency is also improved, especially at light load condition. As can be seen from the small-scale experiment, an increment of 7.8% and 3% of efficiency in forward and backward power transmission modes can be achieved. This promising results make IDBRC as well as the proposed control method possible to be applied in (he DC transmission system.