A Combined Wide and Narrow Pulse Generators for Processing Microbes

This paper proposes a wide pulse combined with narrow pulse generator for solid food sterilization. The proposed generator is composed of a full-bridge converter in phase-shift control to generate high dc-link voltage, and a full-bridge inverter associated with an L-C network and a transformer to generate wide pulses combined with narrow pulses. These combined pulses can prevent undesired strong air arcing in free space, reduce power consumption and save power components, while can sterilize food effectively. The converter and inverter can be operated at high frequencies and with PWM control, thus its weight and size can be reduced significantly and its efficiency can be correspondingly improved. Experimental results obtained from a prototype with plusmn10 kV wide pulses combined with plusmn10 kV narrow pulses and with 10 ~ 50 kW peak output power, depending on pulse width of the output pulses, have demonstrated its feasibility