ABSTRACT:
Among the renewable energy applications,
the most popular inverters are cascaded multilevel inverters. Irrespective of
numerous benefits these inverters face reliability issues due to the presence
of more circuit components in the design. This has been a critical challenge
for researchers in designing inverters with enhanced reliability by reducing
the total harmonic distortion (THD). This paper proposes a 31-level asymmetric
cascaded multilevel inverter for renewable energy applications. The proposed
topology produces waveforms consisting of the staircase with a high number of
output levels with lesser components with low THD. The investigations on the
feasibility and performance of MLI under steady-state, transient, and dynamic
load disturbances. The results are validated from a 1.6kW system which provides
the proposed inverter.
KEYWORDS:
1.
Multilevel inverter (MLI)
2.
total
harmonic distraction (THD)
3.
staircase modulation technique
SOFTWARE: MATLAB/SIMULINK
CONCLUSION:
The proposed inverter is tested
experimentally with resistive and inductive loads. The output waveforms obtained
during the resistive load test clearly show that the phase angle between
current and voltage is zero. And the inductive load testing results show that
the current is lagging voltage. To test the robustness of the proposed scheme,
a load disturbances test is conducted. It is observed that the proposed
topology is well stabilized under load disturbances conditions. The presented
topology provides seven-level and thirty-one level output voltage with only 6
and 10 switches respectively in asymmetrical conditions. Under simulation a THD
value of 3.62% is obtained using SIMULINK. under experimental conditions the
computed THD value is 3.7%. The ability of presented MLI topology has been
veri_ed using both simulation and experimental setups and the results are
demonstrated for both conditions. The suggested topology is appropriate for the
integration of medium-voltage renewable energy and power quality improvement in
DVR, DStatcom and FACTs.
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