APPARATUS AND METHOD FOR WIRELESS POWER TRANSMISSION

• US 20160134129A1
• Filed: 12/28/2015
• Published: 05/12/2016
• Est. Priority Date: 06/25/2013
• Status: Active Grant

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: Masatoshi Watanabe, Tomoya Morinaga
• Inventors: WATANABE, Masatoshi, MORINAGA, Tomoya
• Granted Patent: US 9,929,604 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 5/00 Circuit arrangements for transfer of electric power between ac networks and dc networks H02J3/36 takes precedence
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection

Abstract

A transmission antenna includes a transmission coil, and transmits an electric power signal. A driver applies a driving signal to the transmission antenna. A first temperature sensor measures the temperature of the transmission coil, and generates a first temperature signal. A second temperature sensor measures the temperature of an interface surface on which an electronic device mounting a wireless power receiving apparatus is to be placed, and generates a second temperature signal. A control circuit controls the electric power signal according to the difference between the first temperature signal S11 and the second temperature signal.

Claims

1. A wireless power transmission apparatus comprising:

a transmission antenna that comprises a transmission coil, and that transmits an electric power signal;

a driver that applies a driving signal to the transmission antenna;

a first temperature sensor that measures a temperature of the transmission coil, and that generates a first temperature signal;

a second temperature sensor that measures a temperature of an interface surface on which an electronic device mounting a wireless power receiving apparatus is to be placed, and that generates a second temperature signal; and

a control circuit that controls the driver, and that controls the electric power signal according to a difference between the first temperature signal and the second temperature signal.

2. The wireless power transmission apparatus according to claim 1, wherein, when the aforementioned difference is greater than a first threshold value, electric power transmission is limited.

3. The wireless power transmission apparatus according to claim 2, wherein the control circuit is capable of detecting a foreign object on the interface surface,

wherein, when judgment is made that there is such a foreign object, and when the aforementioned difference is greater than a second threshold value, electric power transmission is limited,

and wherein, when the difference is smaller than the second threshold value, electric power transmission is substantially maintained even if judgment has been made that there is such a foreign object.

4. The wireless power transmission apparatus according to claim 1, wherein, when at least one from among the first temperature signal and the second temperature signal is greater than a thermal shutdown threshold value, electric power transmission is limited.

5. A control method for a wireless power transmission apparatus, the control method comprising:

a driver applying a driving signal based on a pulse signal to a transmission antenna comprising a transmission coil;

the transmission antenna transmitting an electric power signal according to the pulse signal;

measuring a temperature of the transmission coil, and generating a first temperature signal;

measuring a temperature of an interface surface on which an electronic device mounting a wireless power receiving apparatus is to be placed, and generating a second temperature signal;

detecting a difference between the first temperature signal and the second temperature signal; and

controlling the driver according to the difference.

6. The control method according to claim 5, wherein the controlling of the driver comprises:

comparing the difference with a first threshold value; and

limiting electric power transmission when the difference is greater than the first threshold value.

7. The control method according to claim 5, wherein the controlling of the driver comprises:

detecting a foreign object;

limiting electric power transmission when judgment has been made that there is such a foreign object, and when the difference is greater than a second threshold value; and

substantially maintaining electric power transmission when the difference is smaller than the second threshold value even if judgment has been made that there is such a foreign object.

8. The control method according to claim 5, wherein the controlling of the driver comprises:

comparing at least one from among the first temperature signal and the second temperature signal with a third threshold value for thermal shutdown; and

limiting electric power transmission when at least one from among the first temperature signal and the second temperature signal is greater than the third threshold value.