Magnetic-field amplification by a double coil

摘要

In magnetic-resonance wireless power transfer systems, a transmitter is equipped with a floating coil. We investigated the functions of the floating coil by analyzing an equivalent-circuit model of the transmitter. It is derived from the model that currents of the floating coil can be amplified without increasing the power consumption of the transmitter. As a result, strong magnetic fields can efficiently be generated with the floating coil. By solving the model, we obtain formulas for maximizing magnetic-field amplitude at an arbitrary frequency. The validity of our analysis is experimentally demonstrated.