A high-power high voltage power supply for long-pulse applications

This paper describes a concept and physical demonstration of an ultra-high efficiency, small size and low cost 100-kV, 100-kW high voltage power supply designed for long-pulse applications (units of milliseconds to DC operation). Key technology includes a modular HV converter with energy dosing inverters that run at about 50 kHz and have demonstrated an efficiency of 97.5% across a wide range of operating conditions. The inverters´ output voltages are phase-shifted, which yields an exceptionally low ripple of 1% and a slew rate of 3 kV/¿s combined with low stored energy that is less than 10 J at maximum voltage. Modular construction allows easy tailoring of HVPS for specific needs. Owing to high efficiency, small size is achieved without water-cooling. Controls provide standard operating features and advanced digital processing capabilities, along with easiness of accommodating application-specific requirements. HVPS design and testing are detailed. It is shown that the ripple factor is inversely proportional to the number of modules squared. Experimental current and voltage waveforms indicate virtually lossless switching for widely-varying load in the full range of the line input voltages, and fair agreement with circuit simulations. The overall efficiency is as high as 95% at full load and greater than 90% at 20% load, with power factor typically greater than 93%.