A Dithering Technique for Mitigation of Conducted Emission Noise of SiC MOSFET Based VSI Driving an Induction Motor

Power electronics converters have to meet international Electromagnetic Compatibility(EMC) standards i.e. CISPR, IEC for commercial application. Electromagnetic interference(EMI) filters are generally used with converters to meet the standards. These EMI filters are heavy, expensive and space consuming. A dithering technique of switching frequency has been proposed in this article to reduce the conducted EMI. The proposed technique accurately predetermines the exact reduction of noise. This article also illustrates the problem of Resolution Band Width(RBW) in power electronics applications while measuring the noise. Thus, the present article also suggests a modified dithering technique to overcome this problem. Experimental results are presented at different RBW in the present article. The proposed dithering technique and its modification have been validated through a SiC MOSFET-based Voltage Source Inverter (VSI) fed drive. This article also focuses on the advantages of reducing Common Mode(CM) choke and DC bus capacitance which eventually saves space and cost for the entire converter system.