| Today,the development of power electronic technology has entered a new era and new application mode.The field of electronic products in daily life can not leave the switching power supply,but the harmonic pollution caused by the convenience of power equipment to serve human beings can not be ignored.Therefore,researchers in the field of power electronics focus on energy issues such as power consumption and harmonic pollution.Attached to this grand background,power factor correction（PFC）technology is quietly coming.Because of its excellent performance in reducing energy consumption,it can become a hot research direction.The ultimate purpose of power factor correction for the input voltage from the city power grid is to effectively reduce the harmonic pollution caused by the oscillation distortion current to the electrical equipment,and then can greatly improve the working performance of the switching power supply,and do our best to improve the quality of the power grid to the greatest extent.In this paper,how to effectively reduce the loss of switching power supply power devices as a starting point,combined with the harmonic and power factor related theoretical knowledge,through the review of the relevant topological structure of the difference between the pros and cons to explain the reasons for the final choice made in the text.In terms of energy loss,the hard-switching operation of the traditional boost PFC converter limits the improvement of the overall operation efficiency of the circuit,so additional auxiliary circuits are needed to reduce the switching loss.Based on the resonance principle of inductance and capacitor,the soft-switching operation of power switch is realized by transferring and storing energy in the switching process of power switch.In high power applications,boost PFC converter is usually controlled in continuous current mode,which has the advantages of low conduction loss,low ripple current interference and low EMI.Furthermore,through the analysis and comparison of the common control strategies and the grasp of the difficulty of some advanced control methods,the average current control mode is finally advocated for the design of this paper.Then,in Chapter 3,a single-phase boost type soft switching high power factor correction circuit topology based on the analog modulation control chip UC3854 and the traditional structure is optimized is proposed.Then,the working principle of APFC circuit and the working mode of the designed topology are described in detail.The voltage and current waveforms of key power devices in each stage are given.The realization conditions of soft-switching are obtained by using the phase plane analysis method.Finally,the design of 250 W boost ZVS soft switching APFC（Active Power Factor Correction）circuit based on UC3854 is completed.This paper is the result of the close combination of theoretical design and practical simulation.After analyzing and expounding the relevant working process and design ideas,the improved circuit is modeled and simulated by using the simulation software SIMetrix. |
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