Abstract
This article proposes a general mathematical solution for a selective harmonic elimination (SHE) technique. The proposed procedure is valid for both symmetrical and unsymmetrical multilevel inverter (MLI) inverter configurations with a wide range of modulation indexes (mi). The proposed procedure eliminates the targeted number of harmonics " l " for switching angles \text {NS}= 2^{l} regardless to the MLI output waveform levels. The proposed procedure receives the values and ratios of the dc sources, and then, it calculates the NS values to generate a suitable set of harmonic equations. In this proposed algorithm, the nonlinear transcendental harmonic equations were transformed into a linear system of equations ( A X=B ); the resulting equations can be solved online easily by formulating matrix A and matrix B and then multiplying the inversion of matrix A by matrix B. It has been found that only the last element in matrix B needs to be updated for each change in the modulation index or in the ac output fundamental component, resulting in reduced computation time. The proposed technique generates the switching angles \alpha _{1}, \alpha _{2}, \ldots, \alpha _{k} based on a preset objective functions. The simulation and experimental results in some selected cases are provided to validate the proposed algorithms.