This paper investigates the impact of inductance variation in a magnetic integrated double-side LCC compensated wireless power transfer (WPT) topology. The circuit topology with the extra couplings between the compensated coils (inductor) and the main coils is analyzed. Considering the main coil inductance variation, the characteristics of the investigated topology are studied. The compensated receiving coil inductance is found to be an effective tuning parameter to ensure the primary side zero voltage switching (ZVS) operation.
An analytical expression for the current at the switching instant is derived, which is critical for the design of soft-switching operation. Circuit simulation is performed to validate the analytical analysis and to aid the ZVS tuning design. A WPT system with up to 5.6kW output power for electric vehicles has been built to verify the validity of the discussion. The soft-switching is achieved in a wide operation range which leads to overall efficient wireless power transfer.