Analysis of Switching Sequence Operation for Reduced Switch Multilevel Inverter With Various Pulse Width Modulation Methods

Abstract

Pulse width modulation (PWM) methods are used to control the switching sequence operations of conventional multilevel inverters (MLIs) and reduced switch multilevel inverters (RSMLIs). Many researchers proposed various RSMLIs with their switching sequence operation and PWM control techniques. However, the switching operations of RSMLIs are not similar to conventional MLIs, which are a major problem of switch control. Logical equations are proposed for the operation of RSMLIs with the multi-carrier PWM methods like alternative phase opposition disposition (APOD), phase opposition disposition (POD), and phase disposition (PD). To operate the individual switch in symmetrical and asymmetrical RSMLI, logical operators are used to produce required pulse sequence from the sequence of PWM method and their analysis is not present in previous works. The proposed methodology can be applied to PV systems for efficient operation. The proposed methodology and binary representation of PWM method are analyzed on various RSMLIs for seven-level output voltage to operate each individual switch. Control of individual switching sequence and the operation of RSMLIs are simulated using MATLAB/Simulink. THD comparison is presented for RSMLI, DCL MLI, and SCSD MLI with various PWM methods.