Power Factor Correction of AC to DC Converter Using Voltage Pulse Width Modulation (P.W.M) Techniques

Power factor correction is a method aimed at mitigating the negative impacts of electric loads that result in power factors lower than unity. This paper focuses on the various converters, such as inverters and rectifiers, that convert electrical energy from one form to another. Pulse Width Modulation (P.W.M) is explored as a technique for adjusting the mark-to-space ratio of voltage waveforms in order to decrease harmonic magnitudes in the output. The research involves modeling and simulating single-phase and three-phase bridge rectifier circuits' power factors using MATLAB. The findings indicate that the P.W.M method significantly outperforms alternative techniques, particularly under low output voltage requirements. Furthermore, utilizing multiple pulses during each half cycle of the output voltage effectively reduces harmonic content when output voltage is low. The P.W.M technique allows for control independent of the thyristor firing angle, which effectively eliminates switching losses and electromagnetic interference associated with traditional switching methods. These advantages are further underscored by the observation that while P.W.M exhibits many beneficial qualities, there are still limitations in improving the ac input power factor at reduced load voltage levels.