Comparative analysis of multi carrier PWM eleven level inverter with two modulation waves

Abstract

Multilevel Inverter is introduced to reduce the switching stress and to obtain the output voltage with multiple steps to achieve the lowest total harmonic distortion (THD) and improved fundamental VRMS. This paper presents comparison of various methods used for reduction of THD and for improving VRMS. An eleven inverter is triggered by using Bipolar Multicarrier Pulse Width Modulation method, sine and Trapezoidal Amalgamated Rectangular (TAR) references with triangular carriers. There are seven various types of triangular carriers. They are, Phase Disposition, Phase Opposition Disposition, Alternate Phase Opposition Disposition, Carrier Overlapping, Phase Shift and Variable Frequency methods. The Performances measure like, THD, VRMS are evaluated for various modulation indices. Simulation is carried out by using MATLAB/SIMUINK. It is observed that sine reference based PWM method provides lower THD, TAR reference based PWM method provides higher fundamental VRMS output voltage.