Research On High Power SMPS With High Frequence Based On APFC

The active power factor correction technology make the input current accurately track the input voltage waveform, which can increase the input power factor to close with 1 .So that APFC technology becomes an effective method to reduce harmonic current of the current rectifier circuit.With the continuous improvement of the switching frequency of Switching Power Supply,the switching losses have been highlighting because of hard switching of the boost switch.It has been one of hot issues for APFC technology that how to overcome these problems by soft-switching.Based on studying some boost soft switching converters,a Zero Voltage Transition Boost converter is proposed in this thesis. This converter employs an auxiliary resonant circuit to allow the boost switch to turn on and off under zero voltage conditions.Besides that,the auxiliary circuit is also soft-switching when it is turning off.So the converter reduces the switching losses. Based on the analysisi,design guidelines which use UC3855A / B chip to control the converter are given. The system simulation model of 1.2kW,100kHz prototype system is established with Matlab.Simulationresults are presented toverify the feasibility and accuracy of this design.