Patent ID: 9692238
Date: 2017-06-27
CPC Classifications: H02J

Claim:
1. A power transmitting device, which transmits AC power in a noncontact manner to a power receiving device comprising a power receiving antenna, a power receiving circuit that converts the AC power received by the power receiving antenna to first DC power, and a load to which the first DC power is output from the power receiving circuit, the power transmitting device comprising: a power transmitting circuit that converts second DC power input from a DC power supply to AC power; a power transmitting antenna that transmits the AC power output from the power transmitting circuit to the power receiving antenna; and a control circuit that receives, from the power receiving device, a voltage value of the first DC power output from the power receiving circuit to the load in the power receiving device, wherein the control circuit controls the power transmitting circuit to change a frequency of the AC power that is transmitted to the power receiving antenna, detects, from the received voltage values, a first frequency corresponding to a local minimum value of the voltage values and a second frequency corresponding to the voltage value that takes a local maximum value at a frequency higher than the first frequency, and sets the frequency of the AC power transmitted to the power receiving antenna to a frequency between the first frequency and the second frequency.