Microprocessor based power factor improvement for single phase controlled rectifiers using Symmetrical Angle Control

Power Electronics have proved itself as an encompassing field for power generation and 1IlaI1ag4:me Traditionally conversion of ac to de vo~es has been dominated by phase controlled or diode rectifiers. The ideal character of the input current draWnby these rectifiers creates number of problems like increase in .. power, high input current harmonics and low input power factor, lower rectifier efficiency, large input ,distortion etc. To compensate for the higher reactive powerdemand by the converters at high power transfer .' power factor correction becomes mandatOry. In addition to this industrial loadon the power supplies being i reduce the power factor. A poor power factor is translated in heavy expenses to the user i.e. for the same demand if the power factor is poor the sysJem draws more current. There is a growing concern regarding pollution of the power distnbution system. Adoption of the International ElectricalCommission standard lEe s' and IEEE-SI9-1992 has helped greatly in the awareness for clean ac line currents and a power factor close to . In this paper a high performance input power factor correction technique using Symmetrical Angle . .implemented and analyzed for single phase controlled converters. From simulation and experimental ., obtained on a laboratory prototype it can be concluded that input power factor remains nearly unity Ii' variations in the load. r: