Generalized Impedance Modeling Framework with its Application on Modular Multilevel Converter

This paper presents a generalized framework to derive the wideband AC/DC impedances based on the technique of frequency-domain multiharmonic linearization, and the symmetrical modular multilevel converter (MMC) is selected to verify its feasibility. First, the basics towards impedance modeling of MMC are reviewed. Then the modeling framework is illustrated with special efforts executed on each harmonic transfer function matrixes referring to the control strategies adopted in the real project roughly. Both the frequency-scan test and the stability analysis results validate the high accuracy of the theoretical models. Further discussions on the key points are added to enhance the adaptivity and necessity of the framework.