Comparison of seven levels symmetric h-bridge multilevel inverter and seven levels cascaded h-bridge multilevel inverter

Abstract

An inverter is a power converter that transforms DC power to AC power using controlled power semiconductor switches. The inverter is categorized into many types based on output, source, type of load etc. This proposal focused on voltage source inverters. Voltage Source Inverter is further classified as a two-level inverter or classical multilevel inverter. Two-level inverter exhibits many harmonic components in output voltage and must utilize a bulky filter to produce pure sinusoidal voltage waveform. Nowadays, large manufacturing demands extensive and high power. The double-level inverter is not suitable for high power since it need to handle high voltage stress. A Multilevel Inverter topology was introduced to improve the constraints of the traditional inverter. However, Multilevel Inverter exhibit several significant limitations. One drawback is that at larger output voltage levels, the number of necessary semiconductor power switches will increase exponentially. The increased number of semiconductor switches harms system overall efficiency and reliability. This research aims to compare a seven-level Symmetric H-Bridge Multilevel Inverter with Cascaded H-Bridge Multilevel Inverter in terms of several semiconductor switches, AC output Voltage Levels, AC output current, THD, and Voltage stress at buttons. This project aims to design and simulate both topologies using MATLAB/Simulink and compare their performance. It is expected that the Symmetric H-Bridge MLI use a fewer quantity of components and use power switches with lower voltage rating as compared to Cascaded Multilevel Inverter.