EMI Coupling Mechanisms and Mitigations in a DC-DC Converter

The EMI coupling mechanisms of a DC-DC converter in electrified vehicles are investigated for both conducted and radiated EMI. The noise sources and propagation paths are identified and quantified. The results show that the magnetic coupling between noise sources to some sensitive locations, including HV/LV terminals and CAN connector, can cause excessive emissions. The coupling between different components of the EMI filters may also lead to the degradation of the filter performances. Strategies are proposed to reduce the coupling, improve the filter performance and mitigate the emissions. The performances are verified in experiment.