A Cascaded Microsecond-Pulse Generator for Discharge Applications

Gas discharges using pulsed power are a promising and efficient approach for producing low-temperature plasmas at atmospheric pressure. Pulsed power generators vary widely in performance and should be chosen according to the load and application requirements. In this paper, a microsecond-pulselength high voltage (HV) generator is developed for atmospheric-pressure plasma jets that use a cascade-type voltage circuit. The electrical parameters including voltage amplitude, pulse repetition frequency, and pulsewidth, are determined by the trigger system. The voltage amplitude can be up to 10 kV and the pulse repetition frequency varies from 1 Hz to 5 kHz. The unipolar output pulse can be either positive or negative, with either square or triangular wave profile that can also be controlled by the optical trigger system. When the output pulse is a square wave, the rising edge is about 100 ns, the falling edge is approximately 2~μs, and the pulsewidth at the top varies from 0.5 to 30 μs. When the output pulse is a triangular wave, the base of the pulse is from 7 to 62 μs, and the stepped rising edge is from 5 to 30 μs. The HV pulse generator is used for producing helium plasma jets into open air. Preliminary experimental data show the effects of the pulse voltage amplitude, pulse repetition frequency, and pulsewidth on plasma jets, and confirm that the generator can provide a good performance for driving cold plasma jets.