A new single-phase high-power-factor converter with buck and buck-boost hybrid operation

In recent years, a wide variety of high-power-factor converter schemes have been proposed to solve the harmonic problem. The schemes are based on conventional boost, buck, or buck-boost topology, and their performance, such as output voltage control range in the boost and buck topology or efficiency in the buck-boost topology, is limited. To solve this, the authors propose a single-phase high-power-factor converter with a new topology obtained from a combination of buck and buck-boost topology. The power stage performs the buck and buck-boost operations by a compact single-stage converter circuit while the simple controller/modulator appropriately controls the alternation of the buck and buck-boost operation and maintains a high-quality input current during both the buck and buck-boost operations. The proposed scheme results in a highperformance rectifier with no limitation of output voltage control range and a high efficiency. In this paper, the principle and operation of the proposed converter scheme are described in detail and the theory is confirmed through experimental results obtained from 2-kW prototype converter. (C) 2000 Scripta Technica.