for example, I will be charging a 9V battery wirelessly when I transmit an AC signal to the receiver coil there is a DC offset? where does the dc component come from if Dc cannot be transferred wirelessly? what is the theory behind?How about some background information on the basis for your question.
I've seen a DC bias fluxgate used to control power transfer using magnetic shielding material. The normal permeability (μ >>1) of the shield reduces flux until a receiver static magnetic field saturates the shielding material reducing the soft ferrite material permeability (μ ≈ 1 air) allowing for power coupling.
yes, you are correct that the output of the receiver coil is AC, but with DC offset. what is the reason why there is a DC component?The output of the receiver coil is AC. As you need DC to charge a battery you need to convert the AC to DC using a rectifier.
Les.