Soft-Switched Single-Stage Bidirectional High-Frequency Isolated DC-AC Converter

Most bidirectional isolated DC-AC converters belong to a two-stage structure, which suffers from a degraded efficiency and reliability due to the presence of intermediate-link electrolytic capacitors. In this paper, a bidirectional single-stage DC-AC converter with soft-switching characteristics is proposed. The converter eliminates the need for an intermediate-link capacitor, and enables direct power conversion using a simple modulation scheme that is easy to implement in practice. The paper begins with a description of the converter topology, followed by an explanation of the proposed modulation scheme. Furthermore, detailed discussions of the operating principles and soft-switching conditions are provided. Finally, a 1.5 kW experimental prototype is established to validate the correctness and effectiveness of the proposed topology.