Design and Development of Battery Operated 100 KV Portable Charger

Abstract

The increased interest in pulsed power field applications has generated the need for development of compact and remotely operated capacitor chargers powered by rechargeable batteries as a primary power source. With this objective, a compact and portable 100 kV DC to DC converter has to be developed. The high voltage generation scheme will be based on hybrid approach. Suitability of switching devices has to be selected. The main aim of the major project is to develop 100 kV, 40W portable charger using flyback topology and to design a 500 Watts oscillator using full bridge topology. The first phase shows the development of portable 100kV, 40 watts charger using flyback topology. The flyback topology is commonly used below 150 W, because of its low part count and intrinsically better efficiency. High voltage is generated using flyback topology with battery input 12 V in the driver circuit and 12V input on the primary end of the transformer. The transformer is lifted up to 16 kV. Then with the help of Cockroft Walton Multiplier Circuit the voltage is uplifted to a desired level. Cockroft Walton Multiplier converts ac voltage to dc. By increasing the number of stages to nine, 100kV voltage can be obtained. The control part has been fiber optically isolated from high voltage unit due to safety consideration. The report includes details of the driver circuit, flyback transformer and multiplier circuit. The schematic diagram, experimental results and simulation results are shown in the report. The obtained multiplier efficiency is 82.64%. The overall efficiency of the charging power supply is 88.88%. The application of 100kV portable charger i.e. generation and detection of x-rays is also explained.

The second phase shows the design of 500 watts oscillator using full bridge topology. Full bridge topology is used for higher wattages. The input to the oscillator is 12V dc and it is modulated into series of high frequency pulses by pulse width modulator i.e. at 10 kHz frequency. The components used in the oscillator, the simulation results, experimental results with resistive and transformer load are shown in the report.