| Active Power Factor Correction(APFC) technology ,which is adopted in the field of the switching power supply to meet IEC1000—3—2 ,can reduce the input current harmonics and improve the power factor significantly. The hotspot of research focuses first on the perfection of power stage, and secondly on the simplification of control part. In the case of Boost PFC circuit, the output voltage is greater than the input peak voltage. Due to high output voltage, switcbing-on losses and reverse recover loss of diode are considerably large under hard-switched condition.To solve the problem above, some kinds of soft-switched circuit are analyzed and discussed, and a new type of soft-switched circuit has been proposed and used to a 6KW switching system in this paper. The design process can be concluded as follows: first, the out power is 6000W, the range of input voltage is from 160 to 270 volts, the line frequency can be in the range from 47 to 65Hz; secondly, after choosing the switching frequency synthetically at 20KHz, the major parameters (the major inductance 357uH, the major capacitance 6800uF, switch CM200DY-12HIGBT and major diode DXEI2X61 ) can be worked out; third, a new control part has also been designed and put into practice.In the last chapter of the paper, simulation and experimentation has been made with the practical data figured out in the chapters above.Characteristics of the circuit proposed in this paper can be concluded as follows:All semiconductor parts are turned on or off under zero voltage or zero current conditions;Input power factor 0.989998;The efficiency of PFC circuit about 95.8%. |
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