The forward-mode three-level AC/AC converter

A circuit topology of the forward-mode three-level AC/AC converter is proposed. The kind of circuit topologies are constituted of multilevel converter, high frequency transformer, output cycloconverter, and output filters. The converter has the advantages such as concise circuit structure, two-stage power conversions, bidirectional power flow, high frequency electrical isolation, three-level voltage across the output filter, lower voltage stress of the power switches, and so on. The circuit structure is used for transferring the unstable high ac voltage with high THD into a regulated constant frequency sinusoidal voltage. The converters lay the key technical foundation on new-type electronic transformers, regulated sinusoidal ac power supplies and ac regulators. The operation modes, steady principles, control strategy and time condition of magnetic reset of the proposed converter are investigated in the paper, and the converter is compared with the conventional forward-mode two-level AC/AC converter. The correction and advance of the kind of converters are verified by the principle test results.