Wireless power transmission system capable of continuing power transmission while suppressing heatup of foreign objects

Patent metadata

Field	Value
Publication number	US-9768643-B2
Application number	US-201314068453-A
Country	US
Kind code	B2
Filing date	Oct 31, 2013
Priority date	Nov 2, 2012
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

A power transmitting antenna includes a first resonant circuit including a power transmitting coil, a power receiving antenna includes a second resonant circuit including a power receiving coil. When the power transmitting antenna and the power receiving antenna are electromagnetically coupled to each other, the power transmitting antenna and the power receiving antenna have an odd-mode resonance frequency corresponding to an odd-mode resonant condition, and an even-mode resonance frequency corresponding to an even-mode resonant condition, and the even-mode resonance frequency is higher than the odd-mode resonance frequency. A wireless power transmitting apparatus is provided with a power transmitting circuit configured to generate high-frequency power at a variable frequency, and supply the high-frequency power to the power transmitting antenna. A control circuit sets the frequency of the high-frequency power generated by the power transmitting circuit to one of the odd-mode resonance frequency and the even-mode resonance frequency.

First claim

What is claimed is:

1. A control circuit of a wireless power transmitting apparatus in a wireless power transmission system for transmitting high-frequency power from the wireless power transmitting apparatus to a wireless power receiving apparatus,
wherein the wireless power transmitting apparatus comprises a power transmitting antenna including a first resonant circuit including a power transmitting coil,
wherein the wireless power receiving apparatus comprises a power receiving antenna including a second resonant circuit including a power receiving coil,
wherein, when the power transmitting antenna and the power receiving antenna are electromagnetically coupled to each other, the power transmitting antenna and the power receiving antenna have an odd-mode resonance frequency corresponding to an odd-mode resonant condition, and an even-mode resonance frequency corresponding to an even-mode resonant condition, and the even-mode resonance frequency is higher than the odd-mode resonance frequency,
wherein the wireless power transmitting apparatus further comprises:
a power transmitting circuit configured to generate, from input power, high-frequency power at a variable frequency, and supply the high-frequency power to the power transmitting antenna, under control of the control circuit of the wireless power transmitting apparatus; and
at least one sensor configured to detect an abnormal condition due to a foreign object near the power transmitting coil or the power receiving coil, and
wherein, when the power transmitting circuit generates high-frequency power at one of the odd-mode resonance frequency and the even-mode resonance frequency, and the high-frequency power is transmitted from the wireless power transmitting apparatus to the wireless power receiving apparatus, and an abnormal condition due to a foreign object near the power transmitting coil or the power receiving coil occurs, the control circuit of the wireless power transmitting apparatus changes the frequency of the high-frequency power generated by the power transmitting circuit to the other of the odd-mode resonance frequency and the even-mode resonance frequency.

2. The control circuit of the wireless power transmitting apparatus as claimed in claim 1 ,
wherein at least a part of the power transmitting coil includes a winding wound substantially on a plane and has a central portion and a peripheral portion,
wherein at least a part of the power receiving coil includes a winding wound substantially on a plane and has a central portion and a peripheral portion,
wherein the power transmitting coil is provided close to the power receiving coil such that, when the power transmitting antenna and the power receiving antenna are electromagnetically coupled to each other, the central portion of the power transmitting coil is opposed to the central portion of the power receiving coil, and the peripheral portion of the power transmitting coil is opposed to the peripheral portion of the power receiving coil,
wherein a magnetic flux density at the central portion of the power transmitting coil and the power receiving coil is lower when the power transmitting antenna and the power receiving antenna are in the even-mode resonant condition, than when the power transmitting antenna and the power receiving antenna are in the odd-mode resonant condition, and
wherein a magnetic flux density at the peripheral portion of the power transmitting coil and the power receiving coil is lower when the power transmitting antenna and the power receiving antenna are in the odd-mode resonant condition, than when the power transmitting antenna and the power receiving antenna are in the even-mode resonant condition.

3. The control circuit of the wireless power transmitting apparatus as claimed in claim 2 ,
wherein the at least one sensor includes a position sensor configured to detect a position of a foreign object near the power transmitting coil or the power receiving coil, and
wherein, when a foreign object is detected at the central portion of the power transmitting coil and the power receiving coil, the control circuit of the wireless power transmitting apparatus causes the power transmitting circuit to generate high-frequency power at the even-mode resonance frequency and start transmission of the high-frequency power from the wireless power transmitting apparatus to the wireless power receiving apparatus, and when a foreign object is detected at the peripheral portion of the power transmitting coil and the power receiving coil, the control circuit of the wireless power transmitting apparatus causes the power transmitting circuit to generate high-frequency power at the odd-mode resonance frequency and start transmission of the high-frequency power from the wireless power transmitting apparatus to the wireless power receiving apparatus.

4. The control circuit of the wireless power transmitting apparatus as claimed in claim 1 ,
wherein, when an abnormal condition due to a foreign object near the power transmitting coil or the power receiving coil occurs after changing the frequency of the high-frequency power generated by the power transmitting circuit, the control circuit of the wireless power transmitting apparatus stops the transmission of the high-frequency power.

5. The control circuit of the wireless power transmitting apparatus as claimed in claim 1 ,
wherein the first resonant circuit includes a capacitor having one of a plurality of capacitances selectively changed under control of the control circuit of the wireless power transmitting apparatus, and the capacitor and the power transmitting coil forms a plurality of resonators, each of the plurality of resonators corresponding to one of the plurality of capacitances,
wherein each of the plurality of resonators has the odd-mode resonance frequency and the even-mode resonance frequency, and
wherein, when the power transmitting circuit generates high-frequency power at one of the plurality of odd-mode resonance frequencies and the plurality of even-mode resonance frequencies, and the high-frequency power is transmitted from the wireless power transmitting apparatus to the wireless power receiving apparatus, and an abnormal condition due to a foreign object near the power transmitting coil or the power receiving coil occurs, the control circuit of the wireless power transmitting apparatus changes the frequency of the high-frequency power generated by the power transmitting circuit to another frequency of the plurality of odd-mode resonance frequencies and the plurality of even-mode resonance frequencies.

6. The control circuit of the wireless power transmitting apparatus as claimed in claim 5 ,
wherein, when an abnormal condition due to a foreign object near the power transmitting coil or the power receiving coil occurs after trying to transmit the high-frequency power at all of the plurality of odd-mode resonance frequencies and the plurality of even-mode resonance frequencies, the control circuit of the wireless power transmitting apparatus stops the transmission of the high-frequency power.

7. The control circuit of the wireless power transmitting apparatus as claimed in claim 1 ,
wherein the at least one sensor includes a temperature sensor configured to detect a temperature near the power transmitting coil, and
wherein, when the temperature near the power transmitting coil is equal to a first threshold or higher, the control circuit of the wireless power transmitting apparatus determines that an abnormal condition due to a foreign object near the power transmitting coil has occurred.

8. The control circuit of the wireless power transmitting apparatus as claimed in claim 1 ,
wherein the wireless power receiving apparatus further comprises a temperat

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Kanno Hiroshi
• Asanuma Kenichi

Classifications

• H02J7/35

  with light sensitive cells · CPC title

• H02J50/90

  involving detection or optimisation of position, e.g. alignment · CPC title

• B60L50/20

  using propulsion power generated by humans or animals · CPC title

• B60L53/36

  by positioning the vehicle · CPC title

• H01F38/14

  Inductive couplings {(for wireless supply or distribution of electric power using inductive coupling H02J50/10)} · CPC title