Analysis and design of a soft-switching interleaved forward converter for generating pulsed electric fields

This paper presents analysis and design of a soft-switching interleaved forward converter for generating pulsed electric fields to process microbes, which includes food sterilization, waste treatment, pollution control, and medical diagnostics and treatment. Particularly, in the food sterilization, it only causes a little increase in temperature, providing safe, nutritious and fresh quality of food for consumers. To achieve sterilization, the pulse-width of the pulsed electric field varies from tens of ns to hundreds of /spl mu/ s, the period changes from 0.1 to 1 ms and the electric field intensity is from tens to hundreds of kV/cm. In this study, sterilizing waveforms are long pulses stacked with narrow pulses to prevent undesired gas discharge and reduce power consumption. A converter equipped with an interleaving scheme is proposed to generate the pulses. Thus, the converter can operate at high frequencies, its weight and size can be reduced significantly, and its efficiency can be correspondingly improved. Hardware measurements of /spl plusmn/10 kV pulses and 200 W peak power have demonstrated the feasibility of the proposed converter.