Cockcroft-Walton Generator: An Effective Voltage Multiplier for Power Supplies of Square Pulses Driving DBD Plasmas

This report gives prominence to the importance of the traditional Cockcroft-Walton voltage multiplier to the design of pulsed power supplies for dielectric barrier discharge (DBD) applications. Following an inventive concept, a simple Cockcroft-Walton generator is combined with a MOSFET-based switch (in either ``push'' or ``pull'' mode). Thus, the to-be-chopped stabilized dc high voltage is produced by a compact, transformer-less, modular unit, having high flexibility in terms of engineering. This approach leads to well-defined, square, high-voltage pulses of variable amplitude, frequency, and duty cycle. Design, implementation, and proof test of such a prototype are here demonstrated. The prototype yields square pulses as high as 10 kV (plateau value), as narrow as 350 ns (variable pulsewidth up to millisecond, depending on the frequency), rising or falling time close to 20 ns, pulse repetition rates up to 4 kHz, and output mean power up to 150 W. The functionality of the system is demonstrated by driving coaxial, ambient air DBDs of variable lengths, while principal electrical and optical parameters are recorded. Peak power values higher than 70 kW are measured on the DBD side, while the voltage multiplier power efficiency factor remains close to 95%.