Multicarrier Pulse Width Modulation Techniques Research Articles

Performance Estimation of Multicarrier Based Multilevel Inverter

This paper presents performance features of Symmetric and Asymmetric Cascaded Multilevel inverter. Both the Phase shifted and level shifted multicarrier pulse width modulation (MCPWM) technique are used in MLI. The best harmonic performance is improved by Level-shifted multicarrier modulations technique . The objective of this work to propose MCPWM Technique for multilevel inverter with equal and unequal DC sources. The Performances indices like Total Harmonic Distortion (THD), reduction of switches and number of DC Sources is considered. An appropriate method to achieve the MC modulation technique is also presented in this paper.

A Carrier - Based Pulse Width Modulation Control Strategies for Cascaded Multilevel Inverter

In this paper, three novel multicarrier pulse width modulation techniques which uses stepped carrier waveform, unipolar sine carrier waveform and staircase carrier waveforms are proposed for seven-level and nine-level cascaded inverter. In each carrier waveform different techniques such as phase disposition (PD), inverted phase disposition (IPD), phase opposition disposition (POD) and alternative phase opposition disposition (APOD) are implemented. The fundamental output voltage and harmonics obtained in each method are compared with the output waveform obtained with the triangular carrier waveform. The proposed switching technique enhances the fundamental component of the output voltage and improves total harmonic distortion. The different PWM methodologies adopting the constant switching frequency multicarrier with different modulation indexes are simulated for a 1 kW, 3φ inverter using MATLAB/SIMULINK and the results are verified. The effect of switching frequency on the fundamental output voltage and harmonics are also analyzed.