Single-Cycle Resonant Converters: A New Group of Quasi-Resonant Converters Suitable for High-Performance dc/dc and ac/ac Conversion Applications

A new resonant switch and a new family of zerocurrent and zero-voltage mixed-mode switching quasi-resonant converters (QRC’s) called single-cycle resonant converters (SCRC’s) are proposed to improve the performance of the conventional QRC’s. The proposed SCRC’s, which include two active switches operated with zero-current switching (ZCS) and zero-voltage switching (ZVS), respectively, show very simple operation and easiness in control and analysis, and they overcome the limited load range characteristics of the conventional ZCS QRC’s. Furthermore, the SCRC’s can be applied even for a high-frequency ac chopper by replacing unidirectional switches with bidirectional ones. Steady-state operation and characteristics of the buck-type SCRC’s are analyzed and compared with those of the buck-type full-wave QRC (FW-QRC). Experimental results at a 2OO-kHz, 1-kW level are shown to verify the operational principle and characteristics.