Space Vector Modulation for Five-Level Current Source Converter with Optimal Vector Sequence and DC Current Balancing Control

Multilevel current source converter (MCSC) is an effective way to increase the power rating of conventional current source-fed motor drive, especially its current rating. However, there are still several challenges existing in this kind of configuration, which mainly focus on its space vector modulation (SVM) technique and the inherent DC current imbalance issue. In this paper, an SVM scheme with optimal vector sequence and DC current balancing capability is proposed for five-level current source converter (5L-CSC). A kind of five-segment sequence is finally determined as the optimal one over high modulation index operating range. Moreover, a DC current balancing method, which is involved into the SVM scheme, is also designed in this paper, in which the switching states, which generate the small vectors, are selected based on the magnitudes of the DC current differences at positive and negative DC trails. The proposed SVM scheme is verified on a (2MW/4160V/278A) back-to-back 5L-CSC system through simulation.