FREQUENCY VARIABLE POWER TRANSMITTER AND RECEIVER IN FRESNEL REGION AND POWER TRANSMITTING SYSTEM

• US 20110140537A1
• Filed: 10/29/2008
• Published: 06/16/2011
• Est. Priority Date: 10/29/2008
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Takei, Ken
• Granted Patent: US 8,334,619 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• CPC Class Codes: H02J 50/23 characterised by the type of transmitting antennas, e.g. directional array antennas or Yagi antennas
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• 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: H04B 5/22 Capacitive coupling
• CPC Class Codes: H04B 5/24 Inductive coupling
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

An object is to achieve a radio power transmitting system capable of adaptively controlling power transmission efficiency, and the following means for achieving it is proposed. The power transmitting system includes a receiver having a loaded antenna and a transmitter whose transmitting frequency is variable, and it controls power transmission efficiency by using a modulated electromagnetic wave reflected from the receiver. A capacitive element and an inductive element are formed in the antenna, the transmitting frequency of the transmitter is set to be variable, the electromagnetic wave transmitted from the transmitter and reflected by the receiver is modulated, and the power transmission efficiency between the transmitter and the receiver is controlled by using the modulated reflection wave.

Claims

1. A frequency variable power transmitter in Fresnel region used in a frequency variable power transmitting system in Fresnel region having a capacitive element and an inductive element formed in an antenna for transmitting power by electromagnetic wave between a transmitter and a receiver in order to use static field and induction field at the same time in power transmission, setting a transmitting frequency of the transmitter to be variable, and modulating the electromagnetic wave transmitted from the transmitter and reflected by the receiver to control power transmission efficiency between the transmitter and the receiver by using the modulated reflection wave,

the frequency variable power transmitter in Fresnel region comprising:

the antenna;

a frequency variable carrier generator;

a directional coupler;

a demodulator; and

a control circuit, wherein

the reflection wave received by the antenna is divided by the directional coupler, and then, the reflection wave is demodulated by the demodulator, and the frequency of the frequency variable carrier generator can be varied by using the demodulated signal.

2. The frequency variable power transmitter in Fresnel region according to claim 1, wherein

the transmitter has a modulator and modulates a carrier, and a frequency of the modulation is higher than a frequency of modulation carried out to the reflection wave by the receiver.

3. The frequency variable power transmitter in Fresnel region according to claim 1, wherein

the transmitter demodulates the reflection wave from the receiver at a predetermined interval and adaptively controls the carrier frequency of the transmitter.

4. The frequency variable power transmitter in Fresnel region according to claim 3, wherein

the transmitter has a modulator and modulates a carrier, and a frequency of the modulation is higher than a frequency of modulation carried out to the reflection wave by the receiver.

5. The frequency variable power transmitter in Fresnel region according to claim 1, wherein

the transmitter monitors an amplitude of a side band obtained by demodulating the reflection wave from the receiver and adaptively controls a carrier frequency of the transmitter so that the amplitude becomes maximum.

6. The frequency variable power transmitter in Fresnel region according to claim 5, wherein

the transmitter has a modulator and modulates a carrier, and a frequency of the modulation is higher than a frequency of modulation carried out to the reflection wave by the receiver.

7. The frequency variable power transmitter in Fresnel region according to claim 5, wherein

the transmitter demodulates the reflection wave from the receiver at a predetermined interval and adaptively controls the carrier frequency of the transmitter.

8. The frequency variable power transmitter in Fresnel region according to claim 7, wherein

the transmitter has a modulator and modulates a carrier, and a frequency of the modulation is higher than a frequency of modulation carried out to the reflection wave by the receiver.

9. A frequency variable power receiver in Fresnel region used in a frequency variable power transmitting system in Fresnel region having a capacitive element and an inductive element in an antenna for transmitting power by electromagnetic wave between a transmitter and a receiver in order to use static field and induction field at the same time in power transmission, setting a transmitting frequency of the transmitter to be variable, and modulating the electromagnetic wave transmitted from the transmitter and reflected by the receiver to control power transmission efficiency between the transmitter and the receiver by using the modulated reflection wave,

the frequency variable power receiver in Fresnel region comprising:

the antenna;

a switching element inserted in parallel to the antenna;

a control circuit;

a memory; and

a rectifying circuit, wherein

the control circuit turns on/off the switching element at a constant timing previously memorized in the memory.

10. The frequency variable power receiver in Fresnel region according to claim 9, wherein

the rectifying circuit having a plurality of smoothing circuits is distributively allocated at a plurality of points on the antenna, and outputs of the plurality of smoothing circuits are combined by a combining line.

11. The frequency variable power receiver in Fresnel region according to claim 10, wherein

the combining line is allocated on a backside of a conductor constituting the antenna.

12. The frequency variable power receiver in Fresnel region according to claim 9, wherein

a plurality of capacitive elements and inductive elements are distributively allocated between a plurality of different two points on the antenna.

13. The frequency variable power receiver in Fresnel region according to claim 12, wherein

the rectifying circuit having a plurality of smoothing circuits is distributively allocated at a plurality of points on the antenna, and outputs of the plurality of smoothing circuits are combined by a combining line.

14. The frequency variable power receiver in Fresnel region according to claim 13, wherein

the combining line is allocated on a backside of a conductor constituting the antenna.

15. A frequency variable power transmitting system in Fresnel region, wherein

a capacitive element and an inductive element are formed in an antenna for transmitting power by electromagnetic wave between a transmitter and a receiver in order to use static field and induction field at the same time in power transmission,

a transmitting frequency of the transmitter is set to be variable, and

the electromagnetic wave transmitted from the transmitter and reflected by the receiver is modulated and power transmission efficiency between the transmitter and the receiver is controlled by using the modulated reflection wave.

16. The frequency variable power transmitting system in Fresnel region according to claim 15, comprising the transmitter and a plurality of the receivers, wherein

the transmitter transmits carriers having a plurality of different frequencies, and the receiver carries out power transmission from the transmitter by using one specific carrier.

17. The frequency variable power transmitting system in Fresnel region according to claim 16, wherein

control of frequency variation related to the carriers having different frequencies is sequentially carried out at different time points on a time axis, and this operation is repeated.