Common Mode EMI Analysis in Power Electronics Enabled Power System

This paper investigates the common-mode (CM) electromagnetic interference (EMI) in the largely networked power electronics enabled power system. With the increasingly electrified transportation systems such as electric vehicles, aircraft, and ships, various power converters are tightly packaged within a small space to perform missions. In such a tightly networked architecture, the overall CM EMI emitted into the shared ground substantially increases and shows an extremely non-linear variation, resulting unprecedently noisy environment. This is particularly severe with adopting a wide bandgap (WB) power switch in the power network design. State of the art addresses CM EMI analysis of an individual power converter. However, there is limited study on network CM EMI, filled with many power converters. Thus, in this paper, the limitations of conventional CM EMI standards from the device to a power converter network are addressed. Also, the overall network CM EMI and its non-linear behavior have been attempted to characterize. Finally, a new CM EMI mitigation strategy, virtual network filter, at the power network ground has been investigated. The proposed CM EMI network filter could be applied to broader power circuit systems without any trade-off and has the potential to provides an extra degree of freedom to power electronic network architecture designers. The proposed idea is validated with a Medium Voltage CM EMI testbed with a networked converter with SiC switches.