Minimization of power loss and harmonic distortion in grid-tied cascaded multilevel inverters

This paper presents the application of a multi-objective optimization method to minimize two conflicting features, power loss and total harmonic distortion, of grid-tied PWM-based cascaded multilevel inverter. These features are similarly important, thus requiring a compromise because of inherent conflict between them. One major challenge is that these features cannot be expressed simply by mathematical formulas due to nonlinear behaviors of PWM-based inverters. In this paper, a modified normalized boundary intersection (NBI) method is applied as the chosen solution, providing an effective approach in converting a multi-objective optimization problem to one objective. A grid-tied cascaded 11-level inverter has been simulated and results are presented to confirm validity of the suggested technique.