Comparative Analysis between Five Level Conventional and Modified Cascaded H-Bridge Five Level Inverter Using Multicarrier Pulse width Modulation Techniques

 ABSTRACT:

Multilevel Inverters are getting popular and have become more attractive to researchers in the recent times for high power applications due to their better power quality and higher efficiency as compared to two level inverters. This research work presents a detailed comparative analysis of various multicarrier sinusoidal PWM schemes such as In Phase Disposition, Phase Opposition Disposition and Alternate Phase Opposite Disposition implemented on five level conventional and modified cascaded h-bridge inverters in MATLAB/SIMULINK software. Conventional five level topology uses eight switches and suffers from increased switching complexity while modified five level topology uses only five switches and is recommended to reduce switching complexity and switching losses. It also ensures less number of components, reduced size and overall cost of the system. The effect of modulation index (Ma) on the output harmonic contents in various PWM techniques is also analyzed.

KEYWORDS:

1.      Pulse Width Modulation

2.      Total Harmonic Distortion

3.      Cascaded H-Bridge Multilevel Inverter

4.      Modified Multilevel Inverter

5.      Level Shifted Modulation

6.      Phase Shifted Modulation         

SOFTWARE: MATLAB/SIMULINK

CONCLUSION:

 It is observed that POD PWM technique has slightly less %THD than IPD and APOD in conventional as well modified MLI. Also, it is concluded that increasing Modulation Index (Ma) reduces %THD. Conventional and Modified MLI has almost same total harmonic distortions but Modified MLI uses only 5 switches whereas Conventional MLI uses 8 switches, hence switching complexity, switching losses and cost of the system is reduced and Modified MLI is recommended to be better choice.

REFERENCES:

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