A Heuristic Method: Differential Evolution for Harmonic Reduction in Multilevel Inverter System

In this paper, Differential Evolution (DE) optimization technique is applied to determine optimum switching angles for cascaded multilevel inverter topology with non equal dc sources for eliminating pre specified order of harmonics while maintaining the required fundamental voltage. This paper discusses briefly an efficient Differential Evolution algorithm (DE) that reduces significantly the computational burden resulting in fast convergence. An objective function describing a measure of effectiveness of eliminating selected order of harmonics while controlling the fundamental component is derived. This technique can be applied for any number of levels; as an example in this paper 7-level inverter with different modulation indices and switching angles are reported. Then, these angles are used in simulation to validate the results.