Model-Based Design for Reactors of the Modular Multilevel Converter

Abstract

For complex power electronic converters, typical design approaches divide the system into multiple independent subsystems without sufficiently considering the interactions among them. In this paper, a model-based approach for sizing the reactors of the modular multilevel converter (MMC) is proposed. The proposed method quantitatively considers the interactions between the reactor sizing and other design parameters, such as power ratings, protection schemes, and component-level shortcircuit capabilities. Meanwhile, three deterministic factors are provided in this paper for sizing reactors to ensure enough robustness during extreme situations instead of the heuristic factor in the existing work. The quantified interactions presented in this paper also reveal that a proper over-rating of the active components is able to reduce reactance, increase efficiency, and improve power density. The proposed method not only serves as a quantitative design tool for the MMC, but also emphasizes the significance of the modeling of the interactions in the modelbased design. Finally, the effectiveness of the proposed method is validated by simulations and experiments. This paper is also accompanied by software codes for reproducibility.