Optimal design of inductors with aluminum litz wire for inductive power transfer systems

This work presents a design method for magnetic couplers with aluminum litz-wire for wireless vehicle chargers. This alternative is considered due to its potential benefits, such as lightweight and cost savings. The work not only proposes the replacement of copper wire with aluminum but also proposes an analytical method to obtain the optimal aluminum volume that maximizes the efficiency of the inductive link. The optimal aluminum volume is expressed as the product of the number of turns of the magnetic coupler by the cable’s number of strands. The optimization strategy pursues the maximization of the product of the magnetic coupling coefficient and the quality factor. This product is considered a figure of merit in the proposed method. The method is used to design an aluminum inductive link fitting the standard SAE J2954. The performance of a prototype of 12 kW is evaluated and compared with a conventional copper litz-wire implementation.