Elimination of Harmonics in a Five-Level Diode-Clamped Multilevel Inverter Using Fundamental Modulation

ABSTRACT:

In this study, elimination of harmonics in a five level diode-clamped multilevel inverter (DCMLI) has been implemented by using fundamental modulation switching. The proposed method eliminates harmonics by generating negative harmonics with switching angles calculated for selective harmonic elimination method. In order to confirm the proposed method, first Matlab/ Simulink and PSIM simulation results are given. Then the proposed method is also validated by experiments with Opal-RT controller and a 10 kW three phase, five-level DCMLI prototype.

KEYWORDS:

1.      Fundamental switching

2.      Harmonic elimination

3.      Multilevel inverter.

SOFTWARE: MATLAB/SIMULINK

CIRCUIT  DIAGRAM:

EXPECTED SIMULATION RESULTS:

CONCLUSION:

The selected harmonic elimination is a popular issue in multilevel inverter design. The proposed selective harmonic elimination method for DCMLI has been validated in both simulation and experiment. The simulation and experimental results show that the proposed algorithm can be used to eliminate any number of specific lower order harmonics effectively and results in a dramatic decrease in the output voltage THD. In the proposed harmonic elimination method, the lower order harmonic distortion is largely reduced in fundamental switching. Furthermore, in the experiments reported here, an induction motor load is connected to the three-phase five-level DCMLI, and the current as well as the voltage waveforms are collected for analysis. The FFTs of these waveforms show that their harmonic content is close to the simulated values.

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