The Design Of Output Series Flyback Converter And Its Key Technology Research

In recent years,with the increasing progress of power electronic technology and switching power supply technology,the application of switching power supply in industry,agriculture,household appliances and other occasions is becoming more and more extensive.The development of the special special high-voltage DC power supply in the corresponding switching power supply is also rapid,and it is widely used in non-destructive detection,high-voltage electrostatic dust removal,high-voltage cable insulation detection,on-site preparation of ozone and other equipment that requires high-voltage DC power supply.In this paper,the application of high-voltage DC power supply in the field of high-voltage electrostatic dust removal is taken as an example to introduce and analyze the circuit topology of some commonly used high-voltage DC power supplies,and the output series flyback circuit structure is proposed as the circuit topology of high-voltage DC power supply And analyze and verify the natural voltage sharing mechanism between its output circuits.In this paper,through the analysis of the characteristics of flyback converters in high-voltage DC applications,it is found that when using a single-output high-voltage DC converter,the transformer primary and secondary inductance turns ratio needs to be relatively large,and the switching tube is in a cycle The ratio of on-time to off-time should be designed to be relatively large.This involves the problem of high stress of the output rectifier diode,which requires the use of diodes with high withstand voltage levels.This will bring about cost control problems and poor recovery characteristics of fast recovery diodes with high withstand voltage levels.Therefore,this paper proposes an implementation scheme of the output series flyback converter.By connecting multiple output windings with the same number of turns in series and winding them in a transformer core,each output is coupled through the coupling between the windings on the secondary side.Natural dynamic voltage equalization can reduce the problem of high withstand voltage of the output rectifier diode and output filter capacitor in each channel,and also realizes the high-voltage DC stable output of the flyback converter.By analyzing the applicable occasions of the two working modes of the flyback converter,the working mode of the output series flyback converter is determined and the working principle of each working stage of the converter within one switching cycle is analyzed.The coupling inductance model of the flyback transformer and the model including leakage inductance,excitation inductance and ideal transformer are established respectively,and the voltage sharing mechanism between the output circuits of the converter is analyzed.According to the characteristics of the converter,the key parameters of the converter are designed and the power devices are selected,and a solution is given to the control method of the output series flyback converter.Through the Saber simulation software,the power main circuit is simulated and verified,and an experimental platform is built to verify the voltage equalization effect.The experiment verified the correctness of the theoretical analysis.