Harmonic elimination of Cascaded Multilevel Inverters Using Particle Swarm Optimization

In this paper, the elimination of harmonics in a Cascaded Multilevel Inverter (CMLI) by considering the non-equality of separated dc sources by using Particle Swarm Optimization (PSO) is presented. Solving a nonlinear transcendental equation set describing the harmonic-elimination problem with non-equal dc sources reaches the limitation of contemporary computer algebra software tools using the resultant method. The proposed approach in this paper can be applied to solve the problem in a simpler manner, even when the number of switching angles is increased and the determination of these angles using the resultant theory approach is not possible. Results show that the proposed method does effectively eliminate a great number of specific harmonics, and the output voltage is resulted in low total harmonic distortion.