Development of an integrated solid-state generator for light inactivation of food-related pathogenic bacteria

This paper is concerned with the design and performance of a fully integrated solid-state Marx generator, which has been developed to drive a UV flashlamp for use in microbiological inactivation. The generator has an output voltage rating of 3 kV and a peak current rating of 2 kA, although the modular approach taken allows for a number of voltage and current ratings to be achieved. The generator is constructed using a number of series-and parallel-connected 1.2 kV insulated-gate-bipolar-transistor (IGBT) switched capacitors. Switching of the IGBT modules is controlled by an optical signal. Details are given of how the optimum IGBT gate-drive circuit is achieved using optical components and a pass-through wire to provide the required energies for individual IGBT modules. The generator is demonstrated as the driver of a UV flashlamp used for inactivation of food-related pathogenic bacteria such as E. coli and Salmonella. The performance of the Marx generator over a period of 10⁶ pulses is examined, along with the changes that occur in the spectrum of the UV flashlamp during the same period.