Research On Single-stage PFC Based On Dual-MOSFET Forward Converter

With only one set of control system,single-stage PFC converter can realize the power factor correction and the fast regulation of output voltage.It is suitable for the application of a variety of occasions because of the advantage of simple structure and low cost.However,the energy-storage capacitor voltage is uncontrollable,varying with the input voltage and load.So how to control the voltage of energy-storage capacitor and achieve the electrical isolation between input and output are the main problems of single-stage PFC converter.A prototype of single-stage PFC based on dual-mosfet forward converter is taken as an example in the paper.First,a new type of single-stage PFC converter,which called single-stage PFC based on dual-mosfet forward converter,is introduced from the analysis of dual-mosfet forward converter and the BOOST-type PFC converter topology.The operation process of various working mode of the converter is analyzed in detail.The control principle and control method of the converter are introduced at the same time.Second,with the help of simulation software SABER,several key parts of the system are simulated.Through the steady-state simulation of the topology structure of the main circuit,simulation of timing of PWM control signal and simulation of the drive circuit,the correctness and feasibility of the theoretical analysis is verified.Third,A prototype of single-stage PFC based on dual-mosfet forward converter is designed,separately from the main circuit,PFC control circuit,PWM control circuit,synchronization circuit,drive circuit and other parts of the design.The calculation method of parameter of the major components and the specific selection of the main components are given in the paper.The circuit schematics of the main parts of the prototype are also given.Fourth,by the testing of PWM drive waveform,the second side waveform of transformer,the input voltage and input current waveform and the output voltage waveform,the correctness of the theoretical analysis and simulation analysis are verified.Finally,the power factor,efficiency,input regulation and load regulation are tested respectively,That the performance index of the prototype achieve the design requirements is proved.At the last of the paper,a summary about the thesis is made.Some suggestion is proposed for next work.