Suppressing Secondary Magnetic Field Radiation for IPT System Using Dual Detuned Receiving Loops

Abstract

With the power improvement of inductive power transfer (IPT) systems, severe eddy loss and heating caused by a strong magnetic field are inevitable. Simultaneously, a mass of ferrite cores is needed to avoid magnetic saturation, leading to the increase of system weight and volume. This work proposes an IPT system with LCC-dual detuned series (LCC-DDS) topology, which can suppress the secondary magnetic field by generating two nearly reverse magnetic fluxes. Besides, the phase difference between dual receiving currents is optimized via finite element simulations to achieve a minimum average magnetic flux density ($B_{\text {ave}}$) in the receiver core. Simulation results reveal that the $B_{\text {ave}}$ of the receiver core in a traditional tuned LCC-Series (LCC-S) IPT system is four times higher than that in the LCC-DDS IPT system. Experiment tests are conducted on the LCC-DDS and LCC-S IPT systems at a 540W transfer power, respectively. The core temperature of the LCC-DDS system is 36.4 °C, while that of the LCC-S system is 42.2°C after a 10-minute operation. It indicates that the proposed method can suppress the magnetic field efficiently.