Wiki article · Collection 02

Frequency Splitting

Engineering reference on Frequency Splitting for wireless power system design, integration, and deployment.

6 minArticle 11/16Resonant WPT

Frequency Splitting — educational diagram — Fig.: Educational diagram for “Frequency Splitting”.

When coupling is strong and Q is high, a resonant link can show frequency splitting (bifurcation): the power or gain curve develops two peaks instead of one. Operating between peaks or jumping between branches can cause sudden power swings, loss of ZVS, or over-voltage on capacitors.

01When splitting appears

High k (tight gap, good alignment) combined with high Q tanks.
Certain SS and related compensations are well-known for bifurcation regions.
Load resistance moves the system across critical coupling boundaries.

Frequency Splitting — supporting diagram — Fig.: Supporting illustration for “Frequency Splitting”.

02Mitigations

Designers may lower Q, choose LCC-like networks with flatter gain, limit the maximum k mechanically (spacer, coil design), or constrain the control frequency sweep so the inverter never parks on an unstable branch. Characterization must include the best-alignment case — not only the worst — because splitting is often a tight-coupling problem.