Control of a multilevel converter using resultant theory

In this work, a method is given to compute the switching angles in a multilevel converter to produce the required fundamental voltage while at the same time cancel out specified higher order harmonics. Specifically, a complete analysis is given for a seven-level converter (three dc sources), where it is shown that for a range of the modulation index m_I, the switching angles can be chosen to produce the desired fundamental V₁=m_I(s4V_dc/π) while making the fifth and seventh harmonics identically zero.