Optimal Pulse Width Modulation of Three-Level Converters With Reduced Common-Mode Voltage

Abstract

This paper presents the computation of three-level optimized pulse patterns (OPPs) that limit the common-mode voltage (CMV) and generate currents with low harmonic distortions. This is achieved by relaxing the symmetry properties of conventional OPPs and by reformulating the associated optimization problem accordingly. As demonstrated by the presented numerical results for a three-level converter driving a medium-voltage (MV) induction machine, the computed OPPs not only limit the CMV but also produce very low harmonic distortions, in some cases even lower than those of conventional OPPs. Experimental results based on a scaled-down, low-voltage (LV) drive system serve as a proof of concept, highlighting the benefits of the proposed OPPs.