Generation of pulsed electric fields for processing microbes

This paper first reviews viable microbe processing mechanism and then presents generation of pulsed electric fields for processing microbes. Microbe processing includes food sterilization, waste treatment, pollution control, and medical diagnostics and treatment. To generate pulsed electric fields for achieving sterilization, a generated high dc output voltage is chopped into pulsed waveforms, in which their pulse-width varies from tens of nanoseconds to hundreds of microseconds, period changes from 0.1 to 1 ms, and electric field intensity is from tens to hundreds of kV/cm. In this study, we propose wide pulses stacked with narrow pulses to prevent undesired air breakdown and reduce power consumption. Modified half-bridge series resonant converters are used to generate high dc voltages. They are operated at high frequency, in discontinuous conduction mode and with a PWM control; therefore, its weight and size can be reduced significantly and its efficiency can be correspondingly improved.