Secondary-side-only simultaneous power and efficiency control for two converters in wireless power transfer system

Electric vehicles (EVs) are very useful but suffer from limited range and long battery charge time. Using wireless power transfer (WPT) allows these issues to be solved. In WPT, the control of the power converters is very important in order to achieve high efficiency and be able to extract the desired power from the source at any time. Until now, it was possible to perform either power control or efficiency control in the secondary side, but not both at the same time. Therefore, the authors propose a novel control for power and efficiency with two converters entirely performed on the secondary side of the wireless system, independently from the primary side. The proposed control allows achieving high transmitting efficiency for the desired power by means of a half active rectifier. Simulations and experiments shows that this method effectively allows achieving high efficiency even when the desired power is varied.