The science
The understanding of advanced MHz technology drives the elegant performance of the IPP wireless charging systems.
THE PHYSICS OF MEGAHERTZ FREQUENCIES
The critical relationship in the physics of inductive power is that the coupling between the transmitter and receiver coils is proportional to f² B², where f is the frequency and B is the magnetic flux density.
The product f.B is called the electromotive density, and the mathematics does not care whether f is low and B is large, or vice versa. However, the engineering does care... A large B and low f mean high electrical currents in the coils (needing thick copper wires), multiple turns, and ferrite cores. Each of these adds cost, weight, and performance inefficiencies.
For historical legacy reasons to do with the ready availability of induction heating power electronics, other commercial wireless power systems use kHz frequencies (low f). However, we use MHz frequencies, three orders of magnitude higher, so our electrical currents are three orders of magnitude smaller to get the same performance; the thin skin depth means our copper only needs to be 50 microns (the thickness of a hair), with single turned coils (rings made from copper tube) that are air cored. These are lightweight, and resonant, with performance a magnitude better than anyone else in the world.
We can use 3D printed plastic and electroplating for the rings, super light-weight, configuring them to fit awkward geometries; we don't heat surrounding metals (again, advantage of thin skin depth); or pot in epoxy resin for deep ocean or ATEX applications. It took us 10 years to develop the inverters, rings, and rectifier, but the effort is worth the performance gains.
