Design And Research Of The Theory And Control System Of High Frequency Power Supply

With the contradictions between environment and economic and social development have become increasingly more and more prominent,the country's investment in environmental protection is growing,the high-frequency power supply used in electrostatic precipitator has been more and more popular.As a special power supply,high-frequency power supply has a great correlation with its circuit parameters,and owing to the high output voltage it has a high demand for power protection.The composition of the flue gas in the electrostatic precipitator changes with the working condition,so the control object of the power supply changes too,especially the instability of the equivalent load resistance,which has a great influence on the working state of the power supply.In this paper,first of all,the power supply of ESP is introduced,and the high frequency power supply is selected as the research object.The working principle and mathematical model of high frequency power supply are analyzed in detail,and the voltage character,maximum output voltage character and load character,resonant current peak and series capacitance voltage are studied in detail,and the existing 200W prototype is used to verify the above theory.Secondly,the three-phase power factor in the process of high-frequency power supply is also studied.In order to improve the power factor when three-phase diode rectifier is used in high-frequency power supply,the power factor correction structure of a parallel type is used to improve the three-phase power factor.Thirdly,the equivalent second order mathematical model of high frequency power supply is given by using the experimental method.The PI controller is designed by classical control theory,and the design result is verified by PLECS.Based on TI's TMS320F28335,a minimum control system is designed as the main controller of ESP,and the hardware protection logic circuit is designed by using CPLD,which improves the reliability and fastness of system protection.Last but not least,a 2kW experimental prototype is taken as an example.Particle swarm algorithm is used to optimize the peak of resonant current and a detailed design scheme is given.The correctness of theoretical analysis and particle swarm algorithm design is verified by experimental comparison.