| In order to reduce the harmonics pollution and compliance with power quality and EMC requirements of ac power system,power factor correction (PFC) must be introduced into the switching power supplies. In order to reduce the switching losses of the switching power supplies while complying with the harmonics regulation , demands for soft-switching technique become more and more important. Therefore, PFC and soft-switching techniques are two important research subjects in the field of power electronic.A high performance constant-current power with PFC and soft-switching techniques is researched in this paper. It consists of two basic units .The first unit is boost-type single-stage PFC converter ,the second unit is soft-switching technology flyback converter. A new type of PFC converter , which called soft-switching PFC based on single-stage flyback converter.First of all,the paper introduced the development of PFC technique and soft-switching technique. The operation principle and steady waveforms of various working mode of the converter is analyzed in detail.The paper discusses how to select the resonant parameters to realize the soft-switching , and the simple control circuit with designing.And then,A prototype of soft-switching PFC based on single-stage flyback converter is designed. The design method and selection of the main components is gived about the converter. At last,with the help of simulation software Saber,several key parts of the system are simulated.Experimenta waveforms are presented,at the same time, the power factor,efficiency,input regulation,load regulation and the harmonic content of input voltage and input current are tested respectively,the theoretical analysis is verified by simulation and experimental. That the performance index of the prototype achieve the design requirements is proved.A reliable and practical power is obtained.At the last of the paper,a summary about the thesis is made.Some suggestion is proposed for next work. |
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