Hamed Nademi - Norwegian University of Science and Technology (NTNU
Anandarup Das - Norwegian University of Science and Technology (NTNU
Lars Norum - Norwegian University of Science and Technology (NTNU

The Modular Multilevel Converter (MMC) is a new topology for multilevel converters with potential for medium voltage and high voltage applications. This paper focuses on themodeling technique in the frequency domain of an MMC. Using this frequency domain modeling it is possible to analyze andpredict the harmonic content in the arm current and capacitor voltages. In MMC, a strong harmonic content exists in the arm current, although it is not reflected in the load current. Thisessentially controls the dynamic behavior of the converter. Moreover, explicit derivation of the equations that describe theharmonic evaluation on the floating capacitor voltage has been developed based on the switching functions concept. It can be employed for reducing the ripple voltage using harmoniccomponents in the arm currents. The most dominant harmonics (2nd and 4th) in the arm current are derived analytically and compared in the paper.

Modular Multilevel Converter (MMC); Frequency Domain; Harmonic Analysis;