Frequency-Selective MHz Power Amplifier for Dielectric Barrier Discharge Plasma Generation

Plasma-assisted nitrogen fixation at atmospheric pressure is a clean and decentralized method for fertilizer production. Among many different plasma discharge types, dielectric barrier discharge (DBD) is one of the few that can generate high output of nitrogen compounds at atmospheric conditions for fertilizer usage. Most DBD generators operate at kHz switching frequencies, however, previous research has found that discharge activities occur at the intervals of the greatest voltage slew rate. The finding implies that operating at higher frequencies can lead to more discharge activities and higher plasma generation. This paper presents a MHz Class E power amplifier with frequency selection to generate DBD plasma at two distinct frequencies. The power amplifier achieves a peak efficiency of 91.5% and outputs 600 W at frequencies of 12.4 MHz and 15.5 MHz.