Evaluation of losses in a secondary-side controlled wireless battery charging system

Secondary-side controlled inductive power transfer (IPT) systems are easy to control compared to primary and dual-side control methods, and more importantly, they do not require wireless communication between primary and secondary sides. In this paper, a wireless battery charging system based on secondary-side controlled IPT is analyzed and presented in detail. The proposed control method relies on the detection of the secondary coil current and the transferred power can be fully controlled by the secondary-side active rectifier with reduced number of power switching devices. The steady-state performance of the IPT system is evaluated using a fundamental harmonic analysis method for resistive and reactive control modes of the active rectifier by taking the converter losses into account. Theoretical and simulation results of the designed system are validated by experimental results obtained from the implemented laboratory prototype for charging of a 96-V lead-acid battery.