Design And Analysis Of Sinusoidal Pulse Width Modulation Techniques For Voltage Source Inverter In Ups Application

PWM techniques has been researched for three decades but there is no explicit guidelines on how one can choose the desired technique for particular application especially in power processing devices. Thus choosing a particular PWM technique for UPS application remains a challenging task since UPS operate under varying load conditions. All the techniques appear to give superior performance as well as short-comings when it comes to control of UPS inverter.Several voltage controlled PWM methods have been proposed in literature such as sinusoidal PWM, sinusoidal PWM with third harmonic injection and space vector modulation. All these methods aim at generating a sinusoidal inverter output voltage without low-order harmonics.This paper provides a critical evaluation of sinusoidal PWM techniques for three- phase voltage source inverter for UPS application and proposes a framework and guidelines for the selection of the appropriate PWM technique for specific application area. First, an analytical technique is developed for determining the expression for the modulation signals used in the carrier- based sinusoidal and non-sinusoidal schemes. Then sinusoidal efficient PWM techniques are introduces.Several quality factors such as total harmonic factor, waveform quality and switching losses are measured and investigated, load condition and power factor in the inverter output are determined for each application. Based on these qualities, an optimum technique for each application is identified. The techniques are later verified through simulation and experiment.