Analysis and design of a single-stage three-level PFC AC-DC-converter

In this paper a new three-level single-stage power-factor-corrected ac/dc converter is presented. The proposed circuit integrates the operation of a boost power factor correction converter and a three-level dc/dc converter into one converter. It does not have the problem of high rising intermediate bus voltages at light load conditions that other single-stage converters have and can operate over a wider load range with significantly less output inductor current ripple; moreover, its input current has little distortion. In the paper, the operation of the new converter is explained in detail and analyzed, its steady-state characteristics are determined, and its design is discussed. Experimental results obtained from a prototype are presented to confirm the feasibility of the new converter.