Research On Apfc-based Single Phase High Frequency Pwm Rectifiers

The APFC-based single phase high frequency PWM rectifiers not noly can achineve a hingh power factor correction for switching power supply,reduce harmonic pullution to the gird,but also increase the conversion efficiency of rectifier, Reduce line losses, Save energy.So the APFC-based single phase high frequency PWM rectifiers have a wide range of applied market because of their excellent input and output characteristics.In this thesis, detailed analysis of power factor correction, harmonic suppression and miniaturization for the APFC-based single-phase high-frequency PWM rectifier.Based on numerous of the literature and papers of domestic and international ,this thesis presents the development process, present situation and trend for the single-phase APFC recifer,the advantages and shortcomings of the recgifier and its application. In the thesis the working principle, circuit topology and APFC control technique of the single-phase APFC recifer are briefly introduced. Control technique of CCM is discussed in detail.With the theories analysis above, the circuit topology for the single-phase APFC recifer is designed. While comparing the advantages and disadvantages of several circuits, The recifer is composed of two parts. Boost APFC circuit is used in the first stage. Two-Transistor Forward DC/DC circuit is used in the second stage. And then frame model for the Boost APFC circuit and Two-Transistor Forward DC/DC circuit. Current inner-loop control circuit and voltage outer-loop control circuit are designed for Boost APFC circuit , voltage-loop control circuit is designed for Two-Transistor Forward DC / DC circuit. At the same time, harmonic of the Boost APFC control circuit is deal with in this thesis. The final,Matlab simulation is adopt to verify the feasibility of the design.In this paper, the working principle of the Boost APFC circuit and Two-Transistor Forward DC/DC circuit is analysed in detail. The design of circuit parameters and selection of the switch device is done by technical requirements. And focus on the design of high-frequency transformer. IC ML4824 is a Composite controller,it can control PFC circuit and PWM circuit at the same time.Becouse rising edge control is used for APFC circuit and falling edge control is used for PWM circuit in the IC,so the voltage ripple of capacitance and output voltage is reduced in APFC circuit. Combination of the control IC ML4824 control circuit design parameters are designed for the control circuit.Based on the theory and research, an experimental prototype for single phase APFC rectifier is established. In order to test the rectifier's performance, many experiments are done. The experimental results show that the APFC-based single phase high frequency PWM rectifier meets the design requirements.