Wiki article · Collection 03

Coil-to-Chassis Interaction

Engineering reference on Coil-to-Chassis Interaction for wireless power system design, integration, and deployment.

6 minArticle 41/50Coil Design

Coil-to-Chassis Interaction — educational diagram — Fig.: Educational diagram for “Coil-to-Chassis Interaction”.

Coils never operate in free space on production docks. Steel frames, aluminum trays, fasteners, and reinforcement shift permeability and eddy-current paths. A receiver characterized on a plastic jig can measure 15–30% different L and materially different k when bolted to the AGV belly plate.

Coil-to-chassis interaction cuts both ways: chassis can shield leakage beneficially or add loss; it can also create unintended flux shortcuts that bypass the intended gap.

01Modeling and test

Include simplified chassis CAD in FEM with conductivity assigned.
Sweep coil mount standoff height — small changes matter.
Measure on golden vehicle at multiple battery states (load height).

Coil-to-Chassis Interaction — supporting diagram — Fig.: Supporting illustration for “Coil-to-Chassis Interaction”.

02Mitigation

Standoffs between coil ferrite and steel. Dedicated aluminum flux barriers. Relocate coil away from parallel steel rails running under the winding. Document forbidden retrofit brackets near the coil zone in service manuals.

03Signs of bad interaction

Efficiency drops only on vehicle, not on bench mockup.
Chassis local heating during charge.
Navigation sensor errors correlated with charging (magnetic interference).