Arm Inductance Quantification for Y-Matrix Modulated Modular Multilevel Converter

Y-Matrix Modulated (YMM) Modular Multilevel Converter (MMC) was proposed recently. This modulation utilizes the self-voltage balancing capability of an MMC so that the conventional voltage balancing algorithm of MMC can be eliminated. YMM demonstrates that MMC has inherent self-voltage balancing capability. However, YMM assumes the voltage drop on the arm inductor to be zero to achieve MMC self-voltage balancing. This paper quantitatively justifies the zero voltage drop assumption for YMM based MMC and derives the general state-space model for MMC. Based on the general state-space model, the time-domain state variable dynamics are derived. The arm inductor assumption is justified by using the state variable dynamics. A criterion to determine the arm inductance value is given in this paper to quantify the zero voltage drop assumption. Simulation studies are provided to verify the state-space model derivation and the quantification of arm inductors.