PWM CONVERTERS FOR THREE PHASE AC POWER CONTROL AND AC TO DC CONVERSION, AND SPECIAL PURPOSE DEVICES USING THE SAME

摘要

PWM converters provide buck, boost, buck-boost, flyback, and Cukconfigurations for three phase AC-AC power control. In an AC-DC embodiment,only a single power conversion circuit is used in a configuration including apair of series connected gate turn off devices (transistors and diodes) whichare oppositely poled and oppositely timed, are connected directly to an ACinput source, and provide an output to a high frequency isolating transformer.The transformer provides an output to a rectifier (diodes), which thusprovides the DC output (capacitor). Special purpose, custom power,applications of the converters include alternatives to Uninterruptable PowerSupplies and eliminate the need for local storage. By controlling duty ratioof the converters a simple replacement is provided for a tap-changingtransformer. By providing a plurality of different duty ratios to pluralconverters, a dynamic cluster integrates a plurality of three-phase buses andcontrols the power drawn from each bus.