Wireless power transmission system and power transmitting device

• US 9,692,238 B2
• Filed: 01/30/2015
• Issued: 06/27/2017
• Est. Priority Date: 02/18/2014
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Matsumoto, Hiromu, Kanno, Hiroshi, Yamamoto, Hiroshi, Sakata, Tsutomu
• Primary Examiner(s): Nguyen, Hai L
• Application Number:
  US14/609,530
• Publication Number:
  US 20150236518A1
• Time in Patent Office: 879 Days
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/402 the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge

Abstract

A power transmitting device includes a power transmitting circuit that converts second DC power input from a DC power supply to AC power, a power transmitting antenna and a control circuit that receives a voltage value of the first DC power from the power receiving device. The control circuit changes 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.

Claims

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.

2. The power transmitting device according to claim 1, wherein the control circuit changes the frequency of the AC power during a specified period after the voltage value has reached a specified value,

detects the first frequency and the second frequency from the voltage values received during the specified period, and

sets the frequency of the AC power to a frequency between the first frequency and the second frequency after the specified period has lapsed.

3. The power transmitting device according to claim 1, wherein the control circuit sets the frequency of the AC power to a frequency between the first frequency and the second frequency upon detecting the first frequency and the second frequency from the received voltage values.

4. The power transmitting device according to claim 1, wherein the control circuit, in operation, transmits the AC power to the power receiving antenna in advance, using a plurality of frequencies of the AC power, from a high frequency to a low frequency.

5. The power transmitting device according to claim 4, wherein the high frequency is a frequency higher than the second frequency.

6. A wireless power transmission system comprising the power transmitting device according to claim 1, and the power receiving device.

7. A method of transmitting AC power in a noncontact manner from a power transmitting device to a power receiving device, the power receiving device including 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 method comprising:

converting second DC power input from a DC power supply to AC power;

controlling the power transmitting circuit to transmit the AC power to the power receiving antenna in advance, using a plurality of frequencies of the AC power;

receiving, from the power receiving device, a plurality of voltage values of the first DC power corresponding to the plurality of frequencies of the AC power;

detecting among the plurality of the voltage values of the first DC power received from the power receiving device, a first frequency corresponding to a local minimum value of the voltage values of the first DC power and a second frequency corresponding to a local maximum value of voltage values of the first DC power, the second frequency being higher than the first frequency;

determining one frequency of the AC power used for transmitting the AC power to the power receiving antenna, between the first frequency and the second frequency; and

transmitting the AC power output from the power transmitting circuit to the power receiving antenna.

8. A non-transitory computer-readable recording medium that records a program causing a computer in the power transmitting device to implement the method according to claim 7.