A power electronics device which converts DC power to AC power at required output voltage and frequency level is known as an inverter. Two categories into which inverters can be broadly classified are two level inverters and multilevel inverters. Some advantages that multilevel inverters have compared to two level inverters are minimum harmonic distortion, reduced EMI/RFI generation, and operation on several voltage levels. A multilevel inverter can be utilized for multipurpose applications, such as an active power filter, a static VAR compensator and a machine drive for sinusoidal and trapezoidal current applications. Some drawbacks to the multilevel inverters are the need for isolated power supplies for each one of the stages, the fact that they are a lot harder to build, they are more expensive, and they are more difficult to control in software.
This focus of this thesis is the simulation study of single phase, three phase, two-level, and three-level inverters. Full analysis for two-level and three-level inverters is included. Software packages MATLAB/SIMULINK and RT-LAB were used to study and simulate inverter waveforms in off time and in real time, respectively. Firstly, single phase and three phase inverters are modeled with resistive load and inductive load and their waveforms are observed. Secondly, a two-level inverter (single phase and three phase two-level inverter) is modeled by different ways and suitable switching control strategies (PWM technique) to carry out harmonic elimination. Thirdly, a three-level inverter (single phase and three phase three-level inverter) is modeled by different ways and suitable switching control strategies (PWM technique) to carry out harmonic elimination. Finally, all inverters models are modeled and run in real time by using RT-LAB and the results in both cases (off time and real time) are the same. Two level and multilevel inverters in both cases for single-phase and three-phase are modeled, run and compared. It is formed that in both real time and off time the results were acceptable. Also, some derivations, such as thirteen segments of region 1 for each sector, nine segments of region 2 in each sector, seven segments of region 3 for each sector for three-level inverter, which have never been mentioned before, are derived and the switching sequence for each region in each sector is drawn.