Research On Buck Power Factor Correction

Grid rectifier load will cause a distortion of the input current and the higher harmonic current flowing into the power grid, reducing the stability and reliability of the power grid. A large number of electrical safety accidents make people consciousness of limiting higher harmonic current. Then the power factor correction technology is becoming particularly important. The power factor correction technology and the corresponding control method are introduced in this paper. Now people use boost PFC circuit commonly. But the circuit cannot achieve over or short current protection function. The output voltage of the circuit is too high and not conducive to design the post-regulator DC/DC converter.The buck power factor correction is studied in view of the question of the boost power factor correction, analyzing the reason why people don’t adopt the buck power factor correction in past. And the feasibility and availability of the buck power factor correction circuit are analyzed theoretically. Power factor correction is not necessarily to make the input current waveform into sine wave, as long as meet the EN61000-3-2 standard.The working principle and working process of the buck PFC circuit are analyzed in this paper. And the driving mode and the output voltage detection method are analyzed. The choice of switch, inductor, capacitor, diode and other components are made in buck PFC circuit. The experiments are carried out to verify the buck power factor correction circuit, based on the analysis of input current waveform and higher harmonic current value, finding out the results that meet the standard, and the state when the circuit has a high efficiency.The buck power factor correction is proved a way to realize power factor correction through the analysis of the working process and verification experiment. The output voltage of buck PFC circuit is moderate. The circuit has over or short current protection function, greatly simplifies the design of the post-regulator DC/DC converter, and is suitable for high power density power adapter and base station power supply.