Cyclic Modulation of Active-Clamped Single Power-Conversion AC-DC Converter for Self-Loss Balancing

In this article, we propose a highly efficient active-clamped resonant ac/dc converter with self-loss balancing capability. The proposed ac/dc converter employs a full-bridge active clamp circuit at the grid side and a series resonant circuit with voltage-doubler at the load side. By incorporating the full-bridge active clamp circuit, an input full bridge rectifier can be removed from the grid side of the proposed converter, and thereby that the number of components and conduction loss at its primary side are reduced. Its attractiveness is that this topology and the corresponding cyclic modulation accomplish equal loss distribution at the switches over two cycles of grid voltage, and thereby enables high output power transfer and high reliability. The full-bridge circuit with clamp capacitor naturally recovers the energy stored at the leakage inductor during both positive and negative half grid cycles. Finally, the efficiency improvement and balanced loss distribution are investigated, which shows the benefit of the proposed converter over the conventional converter.