Space Vector Pulsewidth Modulation Based on a Novel Digital Coordinate Transformation for Multilevel Inverters Eliminating Common-Mode Voltages

A novel jk-coordinate transformation is proposed in this article to operate three-phase multilevel inverters (MLIs) with space vector pulsewidth modulation (SVPWM) eliminating the common-mode voltage in the system. The proposed SVPWM in jk coordinates can directly compute online the zero common-mode voltage (ZCMV) switching states while allowing a straightforward implementation of the reduced-loss switching sequence and reduced commutations between sequence transitions. Also, the computation of a single jk vector among the nearest three vectors is sufficient to generate the entire optimized switching sequence. Furthermore, the proposed technique is scalable to MLIs with a larger number of levels without impacting its performance and computational complexity. Consequently, the proposed ZCMV SVPWM technique exhibits minimal computation time compared to preceding techniques that utilize different reduced-complexity coordinate transformations. The effectiveness of the proposed ZCMV SVPWM with an optimized switching sequence is verified experimentally with a 15-level MLI.