Frequency Converter Family A 2 Avionic Instruments Inc. Aerospace Avionic Instruments Inc. (Al') Frequency Converters have been used in military and commercial, airborne, ground, and shipboard applications since the early 1980s. Frequency converter products use a combination of very high frequency switching and current mode control to produce a highly regulated and robust source of AC power. Power ratings are conservative, providing high overloads for electronic equipment that require high start-up currents, repetitive sub-cycle peak currents, and a well-regulated distortion free waveform. Two levels of power are available with output frequencies of 50, 60, or 400Hz. The Mid Power Converter Series provides single phase or three phase power from 1000VA to 12KVA. The High Power Series provides single or three phase power from 2KVA to 42KVA. for Indus t ry - Three phase system outputs operate with accurate phase displacement for any combination of unbalanced loading. Proportional current sharing is maintained under all load conditions for units operated in parallel. Frequency converters use a two-stage power processing topology that includes an input AC to DC transformer rectifier (TRU) and an output DC to AC bridge inverter switching at a very high frequency. Each power stage operates independently. The input AC to DC TRU provides overall device isolation, and supplies the bridge inverter with high voltage DC. The DC to AC bridge inverter, in turn, synthesizes an accurate output sinewave at either 115VAC or 230VAC, and at other international voltages. Fourth generation current mode control, refined and field proven over the past thirty years, is used to provide excellent line and load regulation. The output responds to sudden load changes and sub-cycle peak current demands within microseconds, assuring a stable output, free of load damaging voltage spikes and transients. Al' frequency converters exhibit superior compatib