Efficiency Angle for Wireless Power Transfer Systems with Multiple Receivers

The efficiency angle is a figure of merit for the performance of a wireless power transfer system. However, it is only defined for a system with a single transmitter and receiver. In this work, the definition of the efficiency angle is extended to include multiple receiver configurations. It is exemplified on an inductive wireless power transfer set-up. A graphical representation depicts the relationship between the efficiency angle, the extended kQ-factor, and the maximum efficiency of the system, facilitating the system design process of multi-receiver wireless power transfer systems.