Originally Posted by GrumpyCabbie
We have 3 worldwide fast charge standards developing for ev plugs, potentially with the addition of Tesla too. How many with inductive charging? What if you have the Betamax version in one town and VHS in the next city? Are they 100% safe? What if someone with a pacemaker walks over the pad?
Actually, this is probably the easiest question to answer: You'll use a ferrite based receive coil for receiving the induction field, and that is most efficient around the 40kHz range - lower means higher rated electrical components, faster means more difficult, less efficient electrical control of the generating field.
40kHz is pretty much an industry standard for things like switch mode supplies and such which use ferrite transformers.
So the only requirement for an inductive field is that it is generated at a given frequency, almost certainly 40kHz. The rest is down to the receiver to be efficient at receiving it, self-resonant tuning, etc..
For any equipment, especially medical ones, then a simple matter of adding additional EMC compliance requirements to NOT be susceptible to a 40kHz signal, which many probably are already, intentionally or otherwise.
I think this is a real easy thing to deduce. What is less clear is how
to generate that field, and what are the best designs for on-board induction receivers.