Wireless power transmission system and power transmitting device

Patent metadata

Field	Value
Publication number	US-9692238-B2
Application number	US-201514609530-A
Country	US
Kind code	B2
Filing date	Jan 30, 2015
Priority date	Feb 18, 2014
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

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.

First claim

What is claimed is:

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 .

Assignees

• Panasonic Corp

Inventors

• Matsumoto Hiromu
• Kanno Hiroshi
• Yamamoto Hiroshi
• Sakata Tsutomu

Classifications

• H02J7/42

  with electronic devices having internal batteries, e.g. mobile phones · CPC title

• H02J50/60

  responsive to the presence of foreign objects, e.g. detection of living beings · CPC title

• H02J17/00

  Electricity · mapped topic

• H02J5/005 Primary

  Electricity · mapped topic

• H02J50/80 Primary

  involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices · CPC title