A Discrete Selective Harmonic Elimination Formulation with Common-Mode Voltage Elimination Ability

Common-mode voltage (CMV) is harmful to high-power converter-fed drive systems, thus actively suppressing the CMV that is of great significance. Compared with CMV reduction, CMV elimination is a better choice as it can totally avoid the influence of CMV. In this letter, a discrete selective harmonic elimination (SHE) formulation with CMV elimination ability is proposed, which uses output voltage levels as variables to be optimized instead of switching angles as in conventional SHE models. In this formulation, the optimization objective is low-order harmonic elimination, while CMV elimination is used as a constraint. The output result is the complete full SHE- pulsewidth modulated waveform over one fundamental period, where selected low-order harmonics and CMV have both been eliminated. Experimental results verify the effectiveness of the proposed formulation, and some comparison results are also provided.