A Generalized Space Vector Modulation (SVM) for Multi-Level Three-Phase Converters

The implementation complexity of space vector modulation (SVM) significantly increases in multi-level converters, rendering the SVM an onerous task, if not impossible, in such systems. On the other hand, developed SVMs for multilevel converters achieve modulation objectives such as reducing common-mode voltage and switching loss, harmonic suppression, etc., focusing on a particular topology with limited applicability to other converter configurations. This paper tackles the mentioned challenge by proposing a generalized SVM adaptable to all three-phase converters. The algorithm takes advantage of repetitive patterns in multi-level converters to eliminate the additional computational effort while still achieving modulation objectives other than only providing switch commands as far as generality is not compromised. In the proposed SVM, no look-up table is employed, minimum switching loss is guaranteed, and 33% less switching is achieved as not three phases ever switch during any time interval, and one phase remains constant while the other two switch. A dc-link and flying capacitor voltage balancing algorithm is also introduced, and the properness of the SVM is shown for a five-level active neutral point clamped (ANPC) inverter; results are compared to those from carrier-based modulation techniques, and the superior operation of the proposed SVM is proved.