All-Solid-State Power Modulator for Pulsed Corona Plasma Reactors

Pulsed corona plasma (PCP) reactors of wire-plate design offer novel solutions to problems concerning environmental issues and in a number of industrial processes. Emerging applications include indoor air sterilization and odor removal in air conditioning systems, chemical synthesis in non-thermal plasmas, and plasma reforming of gaseous fuels. We previously reported on experimental investigations of a laboratory sized, wire-plate plasma reactor for pulsed corona treatment of gas flows. Operation with gas flow, at pulse repetition frequencies of between 10 pps and 200 pps, has been achieved at pulse voltage amplitudes of between 10 and >30 kV, at pulse durations of around 0.3 mus (FWHM). High efficiencies of up to 70 g/kWh have been reported using an all-solid-state pulse generator. In this work, we report on the optimization of an all-solid-state power modulator for use with nonlinear loads like pulse corona plasmas. The pulse generator is based on a fast thyristor switch (IGCT) discharging a pulse capacitor, a pulse step-up transformer, and a single-stage magnetic pulse compression. At pulse repetition rates of up to 200 pps, amplitudes of >30 kV into a resistive-capacitive load (1 kohms/200 pF) have been achieved, at risetimes of about 80 ns and a pulse width of 0.3 mus. The pulse generator is insensitive to load variations, in particular to sparking in the reactor. The modulator and its performance concerning experimental results will be described in detail when driving a pulsed corona reactor