الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Traditionally, phase controlled or diode bridge rectifiers have dominated conversion of ac line voltage from utility systems into dc voltage to serve many applications like switched mode power supplies (which is used in personal computers, communication equipment, and process control’ equipment) and electric ,motor drives (including dc and ac drives). The line currents drawn by these converters have waveforms far from sinusoidal. These currents. are commonly having phase shift and containing large harmonic components Various agencies have been considering limits on the harmonic current injection to maintain good power. quality. As a consequence; various. standards and regulations have been established to specify limits on the magnitudes of harmonic current distortion at various harmonic frequencies In the attempt to meet these standards, many rectifier topologies were proposed that provide almost unity power factor. In these converters, the main effort is devoted to the quality of the input current waveform. these topologies use passive or active wave shaping techniques to reduce the harmonic contents in the input current and hence increase the power factor. This work describes the rectifier input current harmonics specifications. The disadvantages of low input power factor rectifiers and a review of all. proposed solutions to improve the rectifier power factor are also introduced. The modeling and control of switching converters used in active input current shaping (taking boost converter as example) are discussed. The design procedure of a 200 Watt active power factor pre-regulator (APFP), followed by its practical circuit configuration, is carried out. The results of the practical. circuit are matched with those obtained in the simulation step. Both the harmonic distortion and the power factor of the rectifier input current were greatly improved by the use of the designed APFP.