High power pulse technology is an important supporting technology for scientific research in the fields of national defense

high and new technology

et al.It has got widespread applications in many aspects.Mainly

pulsed power system is made up of primary energy

power conditioning system

energy storage units

pulse forming network（PFN）

switches and loads

etc.In the application circumstance where the primary energy is electrical energy and the energy storage units are capacitors

the corresponding power conditioning system is called capacitor charging power supply（CCPS）.Series resonant CCPS circuits have three kinds of working modes

one of which is pulse width modulation.Recently

this kind of soft switching technology has been attracted great attention.To investigate the operation process of series resonant CCPS

the schematic diagram as well as the equivalent circuits of different phases are proposed.The mathematic model of the circuit is constructed.Based on the mathematic equations

by using mathematic simulation method

the working state of the resonant circuit is proposed when the output voltage is varied.Besides

the main waveforms of the circuit are given.The experimental results indicate that the control scheme applied is correct and the charging system is effective.