ABSTRACT

In this project, a single stage AC-DC based on dual active bridge (DAB) with natural power factor correction is proposed. A modulation strategy and a control technique have been given to achieve the unity power factor of the AC side without inner current tracking loops and lookup tables. Notch filter is used in the output voltage feedback path to reduce the influence from low frequency output voltage ripple to the regulator. All of the input side power devices can achieve zero voltage switching (ZVS) on and all of the output side power devices can achieve ZVS under certain load conditions with the proposed control strategy. ZVS conditions and parameter design are given in this project. A 1.4kW prototype has been fabricated to verify the effectiveness of the proposed converter and control strategy.