Cancellation of Magnetic Field Leakage in Fundamental and Harmonic Components for Inductive Power Transfer Systems

Inductive power transfer (IPT) systems transmit power via magnetic field, therefore electromagnetic compatibility (EMC) and electromagnetic interference (EMI) issues are caused by the magnetic field leakage from the IPT systems. In this study, we propose a method to cancel both the fundamental and harmonic components of the magnetic field leakage in a multiple-input single-output (MISO) system by only controlling the transmitters and the receiver. The fundamental component of the input voltage and the optimum load impedance are derived to maximize power transmission efficiency (PTE) under the cancellation condition of the magnetic field leakage at the fundamental frequency. The harmonic components of the input voltage that can cancel the harmonics of the magnetic field leakage is calculated by estimating the harmonic components generated by the full-bridge rectifier on the receiver side. Circuit simulations were performed to evaluate the proposed method. As a result of the simulations, it was confirmed that the fundamental and harmonic components of the magnetic field leakage can be suppressed by more than 34 dB compared to the PTE maximization method, and that the reduction in PTE was about 1.7 %.