Wiki article · Collection 04

Input EMI Filter

Engineering reference on Input EMI Filter for wireless power system design, integration, and deployment.

6 minArticle 37/50Power Electronics

Input EMI Filter — educational diagram — Fig.: Educational diagram for “Input EMI Filter”.

Input EMI filters sit between facility AC and the dock PFC or rectifier, attenuating conducted emissions at switching harmonics and WPT-related sidebands coupled back to the line. Filter design must consider source impedance from the grid and load impedance from PFC — mismatch can cause gain peaks.

Filters are not plug-and-play catalog parts at multi-kW — validate on the integrated dock.

01Components

Common-mode chokes on line and neutral.
X capacitors for differential mode; Y capacitors for common-mode — leakage limits touch current.
Optional damping to avoid resonance with long supply cables.

Input EMI Filter — supporting diagram — Fig.: Supporting illustration for “Input EMI Filter”.

02Installation

Filter input side faces the grid; output toward PFC. Keep filter to PFC wiring short and separated from WPT coil cables inside the pedestal. Ground bond per EMC plan — floating filter grounds cause mystery failures.

03Maintenance

Y cap failure increases touch leakage — include in periodic safety checks.
Document approved filter replacements — generic filters may detune compliance.