Simulation of Cascaded H - Bridge Multilevel Inverter with Several Multicarrier Waveforms and Implemented with PD, POD and APOD Techniques

Power Quality has been a problem ever since electrical power was invented and in recent years, it has become the main interest of researchers who are still concerned about finding ways to reduce its negative influence on electrical devices. Harmonics are an important factor in power quality and also to maintain stable power supply performance, so inverters with harmonic reduction is required. In this paper, several multicarrier techniques are evaluated for cascaded H bridge multilevel inverter and being implemented with several level-shifted Pulse Width Modulation (PWM) techniques such as phase disposition (PD), phase opposition disposition (POD) and alternative phase opposition disposition (APOD). The line voltage and total harmonics distortion (THD) are acquired and are compared with the conventional technique. We also propose a modification on trapezoidal multicarrier aiming to reduce the harmonics. This modification introduces a sinusoidal wave compared with modified trapezoidal multicarrier to generate the pulses. To know which technique is the best, these PWM techniques are simulated via MATLAB/SIMULINK. R2014a in order to obtain the line voltages and the total harmonic distortions (THD).