Research On Power Factor Correction Technology Based On Boost Structure

With the extensive application of power electronic devices,the harmonic pollution of power network is becoming more and more serious.Power electronic devices,such as switch converters,contain non-linear elements such as resistors and capacitors,which are non-linear devices.When connected to the power network,the input current waveform of the power network will be distorted to a certain extent,forming a harmonic current,causing harmonic pollution of the power network,and also affecting the safety of the electrical appliances.The appearance and application of Power Factor Correction(PFC)technology has greatly improved the harmonic pollution problem.It is of great significance to study the power factor correction technology to further improve the power factor of the converter.The main work of this paper is as follows:Firstly,the working principle,advantages and disadvantages of various topologies are introduced,and the boost topology is selected as the research object to analyze the mode of the main circuit of power factor correction,and establish a small signal mathematical model for analysis.Based on the average current control mode,the current loop and voltage loop are designed,and an input voltage sampling scheme based on RC filter and quadratic operation is proposed:an RC filter circuit and a quadratic operation circuit are added to the input voltage sampling branch to sample the input voltage more accurately.The feasibility of the improved scheme is deduced and proved,and the improved circuit simulation model is established,The simulation results show that the scheme further reduces the current harmonics,greatly reduces the output voltage spike of the converter,and the output voltage is stable in a shorter time,the power factor reaches 0.99,and the total harmonic distortion(THD)can still be kept less than 5% under different input voltages,further improving the output response speed and stability of the system.Secondly,the one cycle control method is studied,and the control mechanism and stability of one cycle control in boost converter circuit are theoretically analyzed and verified.In order to further improve the dynamic response speed of the converter,suppress the output voltage spike pulse and reduce the output voltage ripple,an improved one cycle control scheme is proposed.Based on the traditional one cycle control,an output load current feedforward branch and output voltage compensation circuit are added.The circuit simulation model is established and analyzed.The simulation results show that compared with the traditional power factor correction,the improved converter has high sinusoidal input current waveform,continuous inductance current,and power factor of 0.99,which effectively reduces the total harmonic distortion rate thd.After the load changes,it can quickly restore stability,the output voltage has no overshoot,and the output voltage ripple rate is less than 5%,which improves the dynamic response and output stability of the converter.Finally,a 300 W converter prototype based on average current control is designed and built for experiment.The prototype design includes main circuit parameter design,control circuit design and protection circuit design such as over voltage and over current.Through the analysis of experimental data and results,the designed experimental prototype meets the designed performance indicators,achieves a good power factor correction effect,and meets the requirements of power factor correction of the converter.