WIRELESS POWER TRANSMISSION SYSTEM

• US 20120112555A1
• Filed: 12/15/2011
• Published: 05/10/2012
• Est. Priority Date: 09/24/2009
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: TOSHIMITSU, Kiyoshi, Onizuka, Kohei
• Granted Patent: US 9,287,716 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices

Abstract

A power feeding device includes an oscillator to generate a high frequency signal, a resonance frequency determining unit configured to determine a resonance frequency to be used for a wireless power transmission, a resonance frequency controller configured to generate a resonance parameter, a resonant circuit to generate electromagnetic inductance, and a communicating unit configured to notify a resonance frequency to the power receiving device before starting a wireless power transmission. A power receiving device includes a communicating unit configured to receive information of a resonance frequency to be used for a wireless power transmission, a resonance frequency controller configured to generate a resonance parameter, a resonant circuit to generate power, a load circuit to operate by the power, a switch to open and close a connection between the resonant circuit and the load circuit, and a determining unit configured to control the switch.

Claims

1. A wireless power transmission system for power transmission from a power feeding device to a power receiving device by wireless, wherein

the power feeding device comprises

a determining unit configured to determine a switching pattern of a resonance frequency, containing at least a plurality of resonance frequencies and a power feeding time length of each resonance frequency,

an oscillation frequency controller configured to determine an oscillation frequency based on resonance frequencies contained in the switching pattern,

an oscillator to generate a high frequency signal by oscillating according to the oscillation frequency,

a first resonance frequency controller configured to generate a resonance parameter based on the resonance frequency,

a first resonant circuit to generate an electromagnetic wave from the high frequency signal following the resonance parameter, and

a first communicating unit configured to transmit the switching pattern to the power receiving device before generating the electromagnetic wave,

the power receiving device comprises

a second communicating unit configured to receive information regarding the switching pattern,

a second resonance frequency controller configured to generate a resonance parameter based on a resonance frequency contained in the switching pattern,

a second resonant circuit to generate power from the electromagnetic wave following the resonance parameter,

a switch to open and close a connection between a load circuit to be connected and the second resonant circuit, and

a judging unit configured to control the switch to connect between the resonant circuit and the load circuit upon receiving the switching pattern.

2. A power feeding device that transmits power to a power receiving device by wireless, the power feeding device comprising:

a determining unit configured to determine a switching pattern of a resonance frequency, containing at least a plurality of resonance frequencies and a power feeding time length of each resonance frequency;

an oscillation frequency controller configure to determine an oscillation frequency based on resonance frequencies contained in the switching pattern;

an oscillator to generate a high frequency signal by oscillating according to the oscillation frequency;

a resonance frequency controller configured to generate a resonance parameter based on the resonance frequency;

a resonant circuit that generates an electromagnetic wave from the high frequency signal following the resonance parameter; and

a communicating unit configured to transmit the switching pattern to the power receiving device before generating the electromagnetic wave, wherein

the power feeding device transmits power to the power receiving device by switching a resonance parameter and the high frequency signal to be supplied to the resonant circuit following the switching pattern.

3. The power feeding device according to claim 2, wherein

the determining unit transmits a new switching pattern to the power receiving device by determining the new switching pattern, and the resonance frequency controller supplies the resonance parameter following the new switching pattern to the resonant circuit, and

the oscillator outputs the high frequency signal following the new switching pattern to the resonant circuit.

4. The power feeding device according to claim 2, wherein in the case of feeding power by using a plurality of the same resonance frequencies in at least one cycle of the switching pattern, mutually different power-feeding time lengths are set to the plurality of resonance frequency in the switching pattern.

5. A power receiving device that receives power from a power feeding device by wireless, the power receiving device comprising:

a communicating unit configured to receive a switching pattern of a resonance frequency, containing at least a plurality of resonance frequencies and a power feeding time length of each resonance frequency;

a resonance frequency controller configured to generate a resonance parameter based on a resonance frequency contained in the switching pattern;

a resonant circuit to generate power from an electromagnetic wave following the resonance parameter;

a switch to open and close a connection between a load circuit to be connected and the resonant circuit; and

a judging unit configured to control the switch to connect between the resonant circuit and the load circuit upon receiving the switching pattern.

6. The power receiving device according to claim 5, wherein the device waits for a power reception by supplying a resonance parameter corresponding to a predetermined resonance frequency to the resonant circuit, and after starting the power reception, switches a resonance parameter to be supplied to the resonant circuit following the switching pattern.

7. The power receiving device according to claim 5, further comprising a measuring unit to measure a power receiving state of the resonant circuit, wherein

the power receiving device notifies a signal indicating the power receiving state to the power feeding device, when a value of the power receiving state is equal to or smaller than a predetermined threshold value.

8. The power receiving device according to claim 5, wherein the measuring unit measures the power receiving state by using any one of or a combination of a power receiving amount of the resonant circuit, a current amount, a voltage value, and an impedance value.