There are tradeoffs between varying objectives and constraints in the design of wireless chargers. These often lead to more complex coil designs. In this project, coils are directly designed to meet performance objectives with Fourier basis function weigh

As the power levels of wireless power transfer for electric vehicles rise, it becomes increasingly important to maximize the efficiency of the system while meeting design constraints such as stray-field inside or outside the vehicle extents, misalignment tolerances, and vehicle ground clearances. This project seeks to design wireless charging system with all of these in mind. Recently, is has been shown that more complex coil geometries, such as three-phase bipolar coils [4], can enable higher power levels under stray field limits vs. traditional circular or rectangular coils. Coil geometry design has been accomplished with finite element analysis (FEA) approaches and analytical methods. FEA-based methods often rely on brute-force iteration with full or partial 3D-modeling of parameterized coils in a specified geometry and many analytical methods are pertinent only to circular or rectangular coils.
This research project is focused on developing a new analytical method to rapidly design WPT systems with complex coil shapes for various objectives and constraints. The method directly designs WPT coil magnetic fields and currents to meet performance objectives and constraints through the optimization of Fourier basis function weights of varying spatial frequencies. Similar approaches have been applied in the design of MRI gradient coils, and electric machines. In the field of WPT, this method has many benefits and does not assume a specific coil geometry, number of turns, or rely on iterative finite-element analysis (FEA) simulations. After the continuous coil shape is optimized, the method can determine coil conductor paths and accurately predict self and mutual inductance for a desired number of turns and calculate the DC-DC losses for various gauges of wire and switching devices. This allows for convenient multi-objective optimization of a broad variety of coil shapes, operating frequencies, and DC-link voltages. Early stages of this project will validate the accuracy of this model with a 6.6kW prototype system.