Research On A Three-Level And Three-Phase Single-Stage Power Factor Correction Circuit

AC/DC converter is the most widely used converter in the power system. In order toreduce the harmonic pollution of power supply and improve the power factor, people areusing more and more power factor correction technology. At present, the single-phase PFC is already developed, but the three-phase PFC is still inthe stage of library works. The three-phase PFC converter based on the Boost topology isbeing widely used for the advantage that it's input current total harmonic distortion is low andit makes input end power factor of the whole circuit into unity power factor closely. But thehigh DC bus voltage stress is an important issue for the single stage topology in practicalapplication. The multiply-level,power factor correction and soft switching technology are the threehotspots of power electronics now. This paper presents a novel three-level three-phase singlestage power factor correction circuit. The three-level structure reduces the voltage stressacross the power switches to 50% of the bus voltage, then it is easy for us to choose theswitching devices, and all the power switches operate under a zero-voltage turn-on condition. Several circuit topologies of AC/DC converters with three-phase PFC are given first inthe paper, and we analyze the inherent reason of the high bus voltage stress of single-stagepower factor correction converter. Secondly, the operation process and power factorcorrection principal of the converter are discussed and analyzed in detail, meanwhile theFourier series analysis of input current is given. The famous software toolkit PSPICE is usedto validating the rationality and correctness of the topology. Then an experimental installationis given. The main devices and parameters, and the novel phase shift digital control circuit aredesigned. Finally, the experimental waveforms and results are given. In conclusion, the correctness and feasibility of this three-level three-phase single stagepower factor correction converter are proved by the theoretical analyses, simulation researchand experimental validation. The input power factor of the converter is about 0.99.