DESIGN, CONSTRUCTION AND TESTING OF A 600V A UNINTERRUPTIBLE POWER SUPPLY (UPS) SYSTEM WITH PHOTOVOL T AIC GENERATOR (SOLAR POWER) BACK U

Abstract

This project highlights the design and construction of an Un interruptible Power ! , Supply with photovoltaic generator back up. This is made possibJe by the use ofbigh curre~ , semi-conductor controllable switches that convert d.c. low voltage power to a.c. line voltage ; " 'j -'\' power. An Uninlerrupt ihle Power Supply l Jni1 thus ensures supply of AC voltage to an Df equipment hy changing over to an inverted haek up DC voltage in the eventAmail1&failu~e or other irregularities in the main supply. ~ I During the process of circuit design"the lJninterruptibfe Power Supply (UPS)t various , ,j ~ •. , • factors such ali change over speed, commutation, output wavefomls and power quality and , J' ' efficiency were considered. '... '\ J , / \ ~:, :, A just switching relay and power transistors are amongst the various componen~' \ ..... employed. The pulses generated from astahle Illllltivihratllr werc used fi"lr firing the base of the power transistors. Although a more ellicient technique is the sinusoidal pulse width modulation. The UPS unit wa.-.; designed to convert a 12V dc supply to feed a 600watts 220V a.c. load at 50Hz frequency, /