Interference Analysis of Metal Conductors for Target-Resonance-Based Detection Method

Frequency bifurcation phenomenon is an important input characteristic of the magnetically coupled resonant wireless power transfer (MCR-WPT) system in overcoupling situation. In this paper, frequency bifurcation phenomenon in MCR is extended to the general transmitter-receiver coupling system, and the two main factors affecting the phenomenon are analyzed. Finally, the phenomenon is introduced into the field of signal detection, and a noncontact detection method based on target coil resonance is proposed in this paper. Since the proposed method is a kind of electromagnetic method, the detection system is highly susceptible to the surrounding metal conductors. Therefore, the detection performance of this method under three metal-environment conditions is analyzed, respectively. Simulations and experiments show that the metal barrier can weaken the detection because of the eddy current effect, but as long as the barrier does not completely isolate the two coils, the method still has strong penetrability. Besides, the metal plate placed parallel outside the transmitter has less influence on the detection when compared with the metal barrier, and the metal plate by the side of the transmitter can even enhance the detection effect. As a consequence, this method has strong stability in metal environment.