ABSTRACT

Direct current (0.C) power can be converted 10 Alternative current (A.C) power at the required frequency and voltage using semiconductor devices. In other words. a solid sate device called inverter alters D.C. power 10 A.C. power. Due to vast usage of power electronic equipment, the harmonics have emerged as a main problem of recent times. it leads to several problems like overheating of equipment, intervention with the nearly equipment through lines of communication, power factor. For the compensation of the harmonics, a device called shunt active filter is used. Inverter draws only essential component of current from the given supply. These fillers are designed by using multilevel inverters and these are better and efficient as compared to the classical inverters.Inverters are classified into two categories as 2-level inverter and multilevel inverter. Multilevel inverters have some advantages over 2- level inverts such as minimum distortion of harmonics. reduced generation of Electromagnetic interference (EMl) and they can be operated on several levels of voltage. Multilevel inverter has more applications. Such as, ii can be used as an active filter and it can also be used as a machine drive for trapezoidal and sinusoidal applications. It also has some disadvantages. For example, at each stage it needs an isolated power supplies, they are much complex to build, more expensive and their control is difficult.
The main focus of this research work includes study of single phase 2-level. single phase 3-level, 3-phase 2-Level and 3-phase multilevel inverters. Main subject of this work is 2-level and 3-level inverters. To study the waveform of the inverter in MATLAB software. First of all, single and three phase inverters are modeled by using inductive and resistive load and their resulting waveforms are noted. Secondly, for the elimination of harmonics a 2-Level inverter is modeled using the PWM
techniques and active shunt filter. Same process is repeated for 3-Level inverter as
for 2-Level inverter.