An Inductive Power Transfer System with A Clamp Circuit Versus Coupling Variations

Misalignment is an unavoidable problem in inductive power transfer (IPT). The coupling variation between coils may lead to the output power change and low efficiency which will reduce the flexibility and stability of the system. In order to ensure the stable power transfer of the system and extend the allowed operation region, this paper proposes an IPT system with a clamp circuit. The proposed IPT system can automatically activate or inactive the clamp circuit in different coupling ranges, so the system can maintain relatively constant power in a large coupling variation. Finally, a 390-W prototype is built to verify the theoretical analysis. The experimental results show that when the coupling coefficient variation is 0.14~0.42, the output power maintains between 355W~390W, and the efficiency is 80.98%~93.31%.