The Design Of Series Resonant Charging Power Supply

With the development of industrial, the scope of application of pulsed power become more and more widely. In pulsed power system, put the high voltage capacitors as energy storage unit, the performance of the charging power determined the stability and the repetition frequency of the voltage, series resonant charging power supply have the advantage of low loss, short circuit capacity, it is very suit to charging the high-voltage pulse capacitor.In this paper, the design of the laser power with input voltage220V, maximum output voltage3kV. According to the storage capacitor charging voltage, use series resonant converter as the based topology. Through analysis the steady-state of the series resonant discontinuous mode, get a series of math formula include resonant inductor current, capacitor voltage and average charging current. Through the methods of simulation, shows the dynamic operating waveform. In order to achieve the requirements of boost and isolation voltage, introducing a high-voltage transformer, however, increasing the switching frequency can lead to the winding voltage increase, at the same time make the distributed capacitance becoming large, by analyzing the transformer equivalent model, propose an effective method to reduce the distributed capacitance of the transformer. Make full use of the leakage inductance of the transformer as part of a resonant inductor, achieved soft switching, reduces the effect of leakage inductance to the circuit parameters.Gives the design process of the main circuit and control circuit. According to the theoretical equation to calculate the value of the resonant inductor and resonant capacitor. The circuit used an open-loop control, take the TL494as the main pulse control chip, output two driving pulse with the dead time can be adjusted, in order to make the drive circuit and the control circuit isolate on electric potential, designed a IGBT driving circuit based on the EXB841, use CD4013achieved overcurrent and overvoltage protection, finally gives the experimental waveforms, the results demonstrate that the power has a strong ability to withstand short circuit and achieved soft switching.