TRANSMISSION-GUARD SYSTEM AND METHOD FOR AN INDUCTIVE POWER SUPPLY

• US 20140125147A1
• Filed: 01/10/2014
• Published: 05/08/2014
• Est. Priority Date: 03/17/2008
• Status: Active Grant

• Current Assignee: Powermat Technologies, Ltd.
• Original Assignee: Powermat Technologies, Ltd.
• Inventors: AZANCOT, Yossi, BEN-SHALOM, Amir, GREENWALD, Oola, ROFE, Arik, RHODES, Dov, MEYUHAS, Noam, LEI-BOVITZ, Alfred
• Granted Patent: US 9,083,204 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H01F 2038/143 for signals
• CPC Class Codes: H01F 27/266 Fastening or mounting the core on casing or support on coil H01F27/30
• CPC Class Codes: H01F 27/36 Electric or magnetic shields or screens movable for varying inductance H01F21/10
• CPC Class Codes: H01F 27/366 made of ferromagnetic material
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/402 the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• 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: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H02J 7/0044 specially adapted for holding portable devices containing batteries H02J7/0045 takes precedence

Abstract

A transmission-guard is disclosed for preventing an inductive power outlet from transmitting power in the absence of an inductive power receiver. A transmission lock is associated with an inductive power outlet and a transmission key is associated with an inductive power receiver. The transmission lock is configured to prevent a primary inductor from connecting to the power supply unless triggered by a release signal via the transmission key

Claims

1. An inductive power transfer system comprising at least one inductive power outlet comprising at least one primary inductive coil wired to a power supply via a driver;

said primary inductive coil for forming an inductive couple having a characteristic resonant frequency with at least one secondary inductive coil wired to an electric load, said secondary inductive coil associated with an inductive power receiver wherein said driver is configured to provide a driving voltage across said primary inductive coil, said driving voltage oscillating at a transmission frequency significantly different from said characteristic resonant frequency of said inductive couple,

wherein said inductive power outlet further comprises a signal detector adapted to detect a first signal and a second signal, and said driver is configured to;

increase said transmission frequency when said first signal is detected by the detector, and

decrease said transmission frequency when said second signal is detected by the detector.

2. The system of claim 1 wherein said transmission frequency lies within a range in which induced voltage varies approximately linearly with frequency.

3. The system of claim 1 said signal detector being configured to adjust said transmission frequency in response to feedback signals.

4. The system of claim 3 wherein said feedback signals carry data pertaining to the operational parameters of said electric load.

5. The system of claim 4 wherein said operational parameters are selected from the group consisting of:

required operating voltage for said electric load;

required operating current for said electric load;

required operating temperature for said electric load;

required operating power for said electric load;

measured operating voltage for said electric load;

measured operating current for said electric load;

measured operating temperature for said electric load;

measured operating power for said electric load;

power delivered to said primary inductive coil;

power received by said secondary inductive coil, and

a user identification code.

6. The system of claim 1 wherein said detector is selected from the list comprising optical detectors, radio receivers, audio detectors and voltage peak detectors.

7. The system of claim 1 wherein said driver further comprises a voltage monitor for monitoring the amplitude of a primary voltage across said primary coil.

8. The system of claim 7 wherein said voltage monitor is configured to detect significant increases in primary voltage.

9. The system of claim 1 comprising a power converter selected from the group comprising:

a transformer, a DC-to-DC converter, an AC-to-DC converter, an AC-to-AC converter, a flyback transformer, a flyback converter, a full-bridge converter, a half-bridge converter and a forward converter.

18. The inductive power receiver of claim 1, said signal transmitter being configured to send a control signal for transferring a feedback signal from said secondary inductive coil to said primary inductive coil for regulating power transfer across an inductive power coupling.

10. A method for regulating inductive power transmission from a primary inductive coil, wired to a power supply via a driver, to a secondary inductive coil, wired to an electric load, said method comprising the following steps:

providing an oscillating voltage to said primary inductive coil at an initial transmission frequency ft which is substantially different from a characteristic resonant frequency fR of the system;

inducing a secondary voltage in said secondary inductive coil;

monitoring power received by said electric load;

sending a feedback signal when the monitored power deviates from a predetermined range;

said driver receiving said feedback signal; and

said driver adjusting said transmission frequency.

11. The method of claim 10 wherein the step of sending a feedback signal further comprises:

sending a feedback signal of a first type Sa to said driver, whenever said power drops below a predetermined lower threshold, and

sending a feedback signal of a second type Sb to said driver, whenever said power exceeds a predetermined upper threshold.

12. The method of claim 10 wherein said initial transmission frequency ft is higher than the characteristic resonant frequency fR

13. The method of claim 10 wherein the step of said driver adjusting said transmission frequency further comprises:

said driver reducing said transmission frequency by an incremental value df1 when the received feedback signal is of the first type Sa, and

said driver increasing said transmission frequency by an incremental value +df2 when the received feedback signal is of the second type Sb.

14. An inductive power transfer system comprising inductive power receiver comprising at least one secondary inductive coil wired to an electric load, said secondary inductive coil for forming an inductive couple having a characteristic resonant frequency with at least one primary inductive coil associated with an inductive power outlet comprising at least one driver configured to provide a driving voltage across said primary inductive coil, said driving voltage oscillating at a transmission frequency significantly different from said characteristic resonant frequency of said inductive couple,

wherein said inductive power receiver further comprises:

a power monitor for monitoring power received by said electric load; and

a signal transmitter for communicating;

a first signal when said power received is below a predetermined range, and

a second signal when said power received is above a predetermined range.

15. The inductive power receiver of claim 14, wherein said signal transmitter comprises a transmission circuit wired to said secondary inductive coil, said transmission circuit for connecting at least one electric element to said secondary inductive coil thereby changing said resonant frequency such that change in transmission voltage may be detected by a peak detector associated with said inductive power outlet.

16. The inductive power receiver of claim 15, said secondary inductive coil being wired to two inputs of a bridge rectifier and said electric load being wired to two outputs of said bridge rectifier wherein said transmission circuit is wired to one input of said bridge rectifier and one output of said bridge rectifier.

17. The inductive power receiver of claim 15 wherein said transmission circuit further comprises a modulator for modulating a bit-rate signal with an input signal to create a modulated signal and a switch for intermittently connecting said electrical element to said secondary inductive coil according to said modulated signal.

19. The system of claim 14 said signal transmitter being configured to send feedback signals carry data pertaining to the operational parameters of said electric load.

20. The system of claim 15 wherein said operational parameters are selected from the group consisting of:

required operating voltage for said electric load;

required operating current for said electric load;

required operating temperature for said electric load;

required operating power for said electric load;

measured operating voltage for said electric load;

measured operating current for said electric load;

measured operating temperature for said electric load;

measured operating power for said electric load;

power delivered to said primary inductive coil;

power received by said secondary inductive coil, and

a user identification code.