Study On A Boost Bridgeless PFC Circuit Based On One Cycle Control

The harmonic currents are main pollution source in electronic systems, and the attention about reducing harmonic pollution is increasing。Power factor correction technology (PFC) can shape line current and eliminate the undesirable effects on power network by the line current harmonics. Consequently it is an effective method of restraining harmonic currents and increasing power factor。Main circuit topologies and control methods are analyzed and compared on the basis of power factor correction, which characteristics are summarized.In this thesis,a bridgeless PFC circuit based on One Cycle Control(OCC)has been researched.Traditional PFC circuit is boost circuit with rectifier bridge,which have a larger conduction, and seriously limits its application in the high-power occasions. In recent years,the bridgeless boost PFC topology was proposed.By omitting rectifier,this proposed topology greatly reduces the conduction losses. This thesis analysised the structure and working principle of the bridgeless circuit topology and then chose the bridgeless boost circuit as the PFC circuit topology.It improved the conversion efficiency of the circuit. One cycle control technique is a novel nonlinear control method, it is conceived to control the duty-ratio of the switch in real time so that the average value of the chopped waveform the switch rectifier is exactly equal or proportioned to the control reference. It can eliminate automatically instantaneous error in one cycle。One cycle control used in PFC circuit has particular advantage in the performance.In this thesis,one cycle control technique in boost PFC were analyzed, stability analysis of boost PFC with one cycle control was given,computer simulation has verified the theoretical analysis and the effectiveness of the control strategy.Finally, introduced the IR1150S,which base on the one-cycle control chip technology.This IC dose not need the traditional multipliers and the AC input voltage sensing.A specific steps in circuit design and circuit parameter calculation are given. A bridgeless PFC circuit based on OCC has been manufactured to verify the analysis above.The experimental tests and results indicated that the PFC circuit designed in this thesis can achieve the function of active power factor well.