Trench Structure to Suppress Magnetic Field Leakage From an Aperture in a Metallic Enclosure
In hybrid vehicles, power converters such as inverters and dc-dc converters are installed in the power control unit (PCU). A strong current flows through the inductor of the output filter of the power converter, which causes electromagnetic interference in AM radios and other electrical equipment due to low-frequency noise. In this letter, we attempt to clarify the mechanism of low-frequency magnetic field leakage from the aperture of a simplified metallic enclosure representing a real PCU enclosure. A novel structure is herein proposed that suppresses leakage of the magnetic field by controlling the flow of eddy currents around the aperture. The proposed enclosure is manufactured, and its shielding factor is measured. The shielding factor of the proposed enclosure is confirmed to correspond approximately with that of an enclosure without an aperture.