Study and analysis of three-phase high-frequency AC cycloconverter based on pulse density modulation

A new three-phase high frequency AC cycloconverter based on a novel control method-pulse density modulation (PDM) is proposed in this paper. Because the frequency of the input voltage of converter is quite high, PDM cycloconverter permits the synthesis of variable amplitude DC and variable frequency AC signal from the high frequency voltage. Using the soft-switching, PDM cycloconverter has the advantages of the lower switch losses, the faster system response. The principle and mathematic model of the cycloconverter is depicted in details. And the harmonics analysis of output voltage is described. The simulation results prove that the PDM cycloconverter has the merit of easy control, no acoustic noise, and lightweight. So this new three-phase high frequency AC cycloconverter is suited to the UPS, electric vehicle and so on.