Modulation strategy for new asymmetrical multilevel inverter topology using nearest dc level modulation technique

Abstract

Multilevel inverters (MLI) have an important portion in power processing in power systems. These inverters have some inherent advantages such as ability to operate with high power and voltage, improved output waveform quality, and flexibility, which make them attractive and more popular. In recent years, research on multilevel inverters with reduction of components is gaining interest. The reduction offers plenty of advantages namely, the reliability, volume and control simplicity. In this project, Nearest DC Level Control (NLC) modulation technique will be studied and designed for a newly developed multilevel inverter with reduction in components. The proposed NLC modulation is a fundamental frequency switching technique that may have some advantages when applied to multilevel inverters as compared to conventional carrier based PWM modulation. For the study, new topology of nine-level asymmetrical multilevel inverter model will be developed using MATLAB. A proposed NLC techniques will be also developed. The inverter model will be simulated using the same resistor load value. The discussion will be on the shape of the harmonics profile and Total Harmonic Distortion (THD) value.