Patent ID: 8664802

Claim:
A wireless energy transfer device, comprising: a power transmission unit that generates an oscillating magnetic field or an oscillating electric field; a power reception unit, which is provided with a receiving antenna, and which converts the oscillating magnetic field or the oscillating electric field of the power transmission unit to electric power with the receiving antenna; and an electric power theft suppression unit that suppresses a theft of energy with the oscillating magnetic field or the oscillating electric field generated by the power transmission unit, wherein the electric power theft suppression unit comprises: a frequency changing unit that changes a frequency of the oscillating magnetic field or the oscillating electric field generated by the power transmission unit, a first resonance frequency changing unit that changes a resonance frequency of the receiving antenna according to the change in the frequency of the oscillating magnetic field or the oscillating electric field, a detection unit that detects a second oscillating magnetic field or a second oscillating electric field formed in a vicinity of the power transmission unit, and an electric power theft determination unit that determines whether the electric power is stolen based on a status of the second oscillating magnetic field or a status of the second oscillating electric field detected by the detection unit during transmission of the electric power from the power transmission unit to the power reception unit.