A general approach to tuning of a dual secondary winding transformer for wireless power transfer

The concept of multi secondary transformer is well known in electrical engineering. Extending that concept to wireless power transfer transformers brings advantages such as the possibility of supplying power to independent subsystems or to increase primary to secondary misalignment tolerances. An example of such transformer is a long primary multiple car charging system or multi secondary rail vehicle. In this paper an analysis of a WPT transformer with dual load output is provided. A systematic approach is used to specify a sufficient condition for decoupling the secondaries to achieve load independent compensation and tuning. It is further shown that the proposed decoupling condition is applicable to an arbitrary number of secondaries.