Principle aim in standard Selective Harmonic Elimination pulse wide modulation (SHE-PWM) is elimination of low-order harmonics as well as production of desired fundamental component. To accomplish this objective, a set of N switching angles should be determined. In fact, N-1 angles are hired to remove N-1 harmonics from voltage waveform and one angle is allotted to produce the fundamental. This paper presents a solution in order to remove low order harmonics as much as possible. It suggests eliminating next harmonic instead of highest order harmonic in infeasible points. A genetic algorithm is employed to solve the new transcendental equation for finding the switching angles. The proposed method is experimentally applied to a seven-level cascaded H-bridge inverter. The results confirm the validity and effectiveness of the proposed method in extending modulation index range.
THD Analysis of Novel Envelop with a T type (E-T) Multilevel Inverter with reduced number of switches