Design of a switch mode AC voltage regulator with improved performance

Power quality describes the quality of voltage and current and is one of the most important considerations in domestic, industrial, and commercial applications today. Power quality problems commonly faced are transients, sags, swells, surges, outages, harmonics, and impulses. Among these voltage sags and extended under voltages have the largest negative impact on industrial productivity, and could be the most important type of power quality variation for many industrial and commercial customers. Voltage sags is mainly due to the fault occurring in the transmission and distribution system, loads like welding and operation of building construction equipment, switching of the loaded feeders or equipments. Continuous voltage sags are also prevalent in many areas due to inadequate supply and demand situation. In this paper a switch mode AC voltage regulator is proposed to maintain constant voltage across a medium size domestic or commercial appliance. The proposed regulator has the capability of delivering sinusoidal input current with nearly unity power factor and the efficiency of the proposed regulator is high. This system incorporates high-speed insulated gate bipolar transistor switching technology. In this regulator the gate signal of the switching devices is generated by using a compact and commercially available IC chip SG1524B.