Selective harmonic elimination for extended cascaded multicell multilevel power converters

This paper provides general solutions for nonlinear transcendental equations to determine the feasible switching angles for a fundamental frequency-switching-scheme modulated cascaded multicell multilevel power converter with a higher number of modules (H-bridges) and output voltage levels in order to eliminate the dominant low-order line-to-line voltage harmonics. Afterwards, for each cascaded multilevel converter, a feasible range of modulation index that culminates in a viable switching angles for a low switching-frequency selective harmonic elimination strategy is derived. The provided solutions as well as results expedite the burdensome and arduous computations required in solving the transcendental equations of selective harmonic elimination scheme for cascaded multicell converters with higher number of modules. The transcendental equations are solved by Newton iterative method and the solutions are provided for 11-level to 23-level cascaded multicell converters.