Research on Reflective Properties in the IPT System with Dual Secondary Loops

With the widely applying of Inductive Power Transfer (IPT) sharing platforms in public, the security issue imposed by the leaked Electromagnetic Field (EMF) of standby transmitters (Txs) becomes one of the concerned topics. Multiple Txs may be an effective scheme to suppress the leaked EMF, for each Tx can be controlled independently. For traditional technologies, multiple inverters, sensors or wireless communication links are needed to achieve load detection and independent control, which increases the cost and reduces the system reliability. This work presents an IPT system with dual secondary loops, which only needs a single inverter and can automatically control the Txs by its circuitry reflective property. The system can enhance the transmitting current when Rx couples with Tx, and weaken that when Rx doesnt couple with Tx. Further, a capacitor array is added in the secondary circuit to adapt different primary reactance by utilizing a simple switching-control method. Finally, a prototype that can transfer 112W with a DC-DC efficiency of 91.79% is built to validate the feasibility of the proposed system. The experimental results show that the current in coupled Txs is three times higher than that in uncoupled Txs as per the theoretical analysis.