A Single-stage PFC by Integrating quasi-Bridgeless Boost and LLC Converter

摘要

The power supplies usually consists of two stage power converters, which combining the power-factor-correction(PFC) converter circuit with DC-DC post-regulator converter circuit in order to comply with various worldwide specifications governing the harmonic limits of the line current. In general, the Boost converter has been widely used as a PFC circuit. As the power levels are increased or in low line, however, the full-bridge diode rectifier reduces the converter efficiency due to the large conduction losses. To overcome the drawback of the conventional boost converter, the bridgeless boost rectifier has been investigated. By essentially reducing the semiconductor power component number in the current flow path and using soft-switching technique, the converter losses are reduced. However, circuit actually has two energy conversion stages which leads to higher conduction loss in the circuit.In this paper, a research was done on a high efficiency single-stage power converter is proposed for power supplies. The circuit configuration is shown in section I. A quasi-bridgeless boost rectifier with high power factor integrated with soft-switching LLC converter is proposed for a AC-DC converter. Thus, power efficiency is increased through quasi-bridgeless Boost PFC rectification with soft-switching LLC converter and the single-stage operation of the switching devices. The analysis of the proposed converter is presented and the design considerations for 110Vrms, 100 W is discussed. Section II illustrates the various modes of operation for the proposed. Computer simulation and a prototype of the single-stage topology proposed has been built and fully tested. The observed waveforms of input voltage and input current, voltage across on the power switch and efficiency vs input voltage to the proposed converter are shown. In experiment, A high power efficiency up to 91.93% and a power factor over 0.992 were achieved.