The uni-polarity phase-shifted controlled voltage mode AC/AC converters with high frequency AC link

The uni-polarity phase-shifted controlled voltage mode AC/AC converters with high frequency ac link are firstly proposed and deeply investigated. The converters are constituted of input cycloconverter, high frequency transformer, output cycloconverter, input and output filters. It includes full bridge-full wave mode and full bridge-full bridge mode topologies. By using phase shifting control, the leakage inductance energy and the output filtering inductance current are naturally commutated, and ZVS switching of the output cycloconverter are realized, the surge voltage and surge current of the output cycloconverters are overcome. The equivalent circuits within one switching period are carefully analyzed. By using the state-space averaging approach, the converter's averaging model is presented, the output characteristic curve and design criterion of key circuit parameters are given. The converters have the advantages such as high frequency electrical isolation, simple topology, two-stage power conversion, high power density, bi-directional power flow, soft commutation of output cycloconverter, uni-polarity SPWM waveform, no audio noise etc. The correction and advance of the converters are fully verified by principle test. This kind of converter laid the key technical foundation on new type electronic transformers, regulated sinusoidal ac power supplies and ac regulators.