Research And Design Of The APFC Circuit Based On The CUK Converter

With the increasing popularity of electric and electronic instruments, the harmonic pollution in the grid tends to get more and more serious. In order to solve this problem effectively, power factor correction is supposed to be implemented on electric equipment. In fact, methods of power factor correction fall into two categories——Passive Power Factor Correction and Active Power Factor Correction (APFC). However, APFC is a dominating method of improving the power factor, for APFC, within the vast voltage range, can gain the higher power factor and less Total Harmonic Distortion (THD). Though the common way of APFC is via the Positive DC-DC Boost Converter, the Cuk Converter explores a new field for the APFC research due to its relative advantages.The paper firstly puts up with the genesis of the bad power factor and then analyses basic methods as well as technique categorizations of the power factor, expounding its history and status quo at home and abroad. A summary is made based on the operating principle and controlling strategies of the PFC circuit. Later the writer introduces the operating mechanism of the Cuk Converter, deals with various methods of APFC in terms of its main circuit topologic formats and control modes, and deduces key formulas by studying the operating process of the Cuk circuit theoretically. In accordance with the design requirements, this paper proposes an overall design framework and displays the operating principle of the whole circuit. Furthermore, the writer conducts the design and simulation of the sub-circuit under the guidance of the circuit functions. The simulation results testify the correctness of the theoretical analysis by building up the overall simulation circuit, simulating the operation and living up to the predetermined indicators. A specific power circuit, whose PFC circuit can be widely applied to equipment such as the electronic rectifier, the switch power supply and so forth, is designed according to the needs of a car's electricity-supply devices and the working mechanism of the circuit. In the conclusion part of the paper, the writer stresses the referential significance of this circuit in the theoretical research and also points out that there is still plenty of the follow-up work like tolerance analysis and post-layout stimulation if this circuit is intended to put into practice.