A Single-Stage Natural Power Factor Corrector Based on Dual Active Bridge DC-DC Converter without Inner Current Tracking Loop

In this article, a single-stage ac-dc based on the dual active bridge 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. A notch filter is used in the output voltage feedback path to reduce the influence from the 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. The ZVS conditions and parameter design are given in this article. A 1.4-kW prototype has been fabricated to verify the effectiveness of the proposed converter and control strategy.