Evaluation of Objective Functions Used in Bio-inspired Harmonic optimization Algorithms for Multilevel Converters

Various optimization objective functions have been proposed for harmonic optimization problems to eliminate unwanted specific harmonic or reduce total harmonic distortion (THD). However, the objective functions are usually intuitively selected, which lack a theoretical basis. In this paper, five objective functions with different mathematical forms are evaluated by two commonly used bio-inspired optimization algorithms, namely the particle swarm optimizers (PSO), and differential evolution (DE). By comparing the THDs, the low-order individual harmonics, and the computational time, resulted from the five objective functions, some guidelines are summarized for selecting objective functions for the bio-inspired harmonic optimization algorithms.