Analysis of Asymmetrical Cascaded Multi-Cell Multilevel Inverter Employing Multicarrier Level Shifting PWM Technique on Different Loads

Abstract

Background: Multilevel inverters are very exciting alternative for intermediate and other high power drives. The Multicell group is widely growing owing to its advantages such as simplicity in circuit configuration with modularity and expandable. This paper proposes a new circuit configuration of 15 level cascaded H bridge Multicell Inverter which is the mixed form of flying capacitor and cascaded group. Methods: This work suggests a novel structure of new multilevel multicell inverter. The conventional structure uses two positive switch and two negative switch. Here the proposed inverter uses only one positive switch and only one negative switch. The circuit with one DC voltage along with one positive and negative switch forms a cell. Interconnection of more than one cells form multicell structure which is used to generate multilevel output. This multilevel inverter uses asymmetric voltage sources to produce multiple levels at the output. Here, Level Shifting Pulse Width Modulation (PWM) system is used to generate the switching signals to the inverter. Findings: The simulation of the proposed work shown with few number of semiconductor switches, is capable of achieving 15 levels at the output. Incorporating the Level Shifting PWM technique, the Total Harmonic Distortion (THD) has been reduced. Application: The proposed Multicell Multilevel inverter is used to drive the induction motor. Further controllers like PI, Fuzzy and Neuro can be added to reduce the THD and to develop the power quality.