Electromagnetic Field Modeling for the Charging Pads of a 50 kW IPT System and Mechanical Design for the Pad's Casings

MSc thesis of César de la Garza

The working principle of the Inductive Power Transfer (IPT) wireless charging technology is based on two coils separated by an air gap and magnetically coupled together; the first goal of this thesis is: Design an accurate and modular casing for the coils of an IPT system that will fix such elements in the correct position. The result of such design was a casing that was actually manufactured and assembled, and that is currently being used to test a 50 kW IPT prototype system. The second objective of the thesis is: Derive the parasitic capacitance of the coils in order to predict a possible over-voltage across such capacitance. It was concluded that the parasitic capacitance at the standard operating frequency does not represent a risk of over-voltage, but as the frequency goes close to the resonance frequency, the electric field across the capacitor could reach values up to 14 kV/mm. Such electric field concentration is located mainly between the first and last segments of the coils, and also between the coils and the ferrite cores used to improve the magnetic coupling.