Current Ripple Suppression Of Resonant Constant Current Power Supply For High Voltage Capacitor Charging

In recent years,with the flourishing development of micro-satellites,electric propulsion technology,as one of the means to explore space,has received more and more attention.Among them,the Pulsed Plasma Thruster(PPT)has the advantages of light weight,small size,simple structure,and so on,which occupies a position in the commercial space field.With the increasing variety of space exploration tasks,the performance requirements of PPT in research field are increasing.Today,PPT is developing in the direction of miniaturization,high efficiency,low cost and long life.As the core part of the energy system,it is necessary to further study and improve the high voltage capacitive charging power supply.The traditional LC series resonant charging power supply is widely used for high voltage pulse capacitor charging because of its simple control,good constant current output characteristics and simple structure.However,the single series resonant circuit topology is increasingly unable to meet the current development needs of PPT.In view of the limitations of the input current ripple of this topology,this thesis studies an interleaved parallel Boost structure combined bridge series resonant converter constant current charging power supply.This topology retains the advantages of the original series resonant charging power supply for constant current charging,and multiplies the switch tube through the front and back stage converters.The front interleaved parallel Boost structure is combined with the series resonant circuit.This topology takes advantage of the interleaved parallel structure to reduce the ripple of the input side current.By configuring the duty cycle of the switch tube,the resonant cavity excitation source can be adjusted and the bus voltage can be increased,which reduces the high conversion ratio of the transformer and the size of the inter-turn capacitance,and improves the attenuation of the constant current characteristic from the charging power supply of the traditional series resonant circuit to the later charging period.The constant current charging not only fulfills the requirement of capacitive charging for voltage accuracy,but also reduces the electromagnetic interference of ripple to power supply,realizes power protection and prolongs power supply life.Based on the constant current charging by LC series resonance,this thesis describes the charging power supply topology,modulation strategy,working principle,establishes a mathematical model to analyze its voltage and current output characteristics.The combined constant current charging power supply based on series resonant circuit topology and staggered parallel Boost structure,its structure adjustment,soft switch implementation of switch tube,equivalent circuit and mathematical model in each mode,the effect of staggered parallel structure on input current ripple and bus voltage,and the output characteristics under Boost structure are further described.The ripple suppression ability and constant current output characteristics are verified by PSIM simulation.Calculate and design the hardware of the experimental platform and set up the model.An experimental platform with output of 2k V/200 m A was set up to verify the feasibility of the proposed topology and parameter design.The experimental data were obtained and analyzed through experiments.