SYSTEM AND METHOD FOR PROVIDING SIMPLE FEEDBACK SIGNALS INDICATING IF MORE OR LESS POWER IS REQUIRED DURING INDUCTIVE POWER TRANSMISSION

• US 20140252871A1
• Filed: 05/20/2014
• Published: 09/11/2014
• 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, ROFE, Arik, GREENWALD, Oola, ASHERY, Moti, LEIBOVITZ, Alfred
• Granted Patent: US 9,035,501 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 50/70 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 7/025 using non-contact coupling, e.g. inductive, capacitive

Abstract

An inductive power outlet for providing power to an electric load via an inductive power receiver includes at least one primary inductive coil wired to a power supply via a driver configured to provide a driving voltage across the primary inductive coil such that a secondary voltage is induced in a secondary inductive coil associated with the inductive power receiver. The driver may include a controller configured to receive feedback control signals from the inductive power receiver indicating if more or less power is required. The controller may be further configured to adjust the driving voltage according to the control signals.

Claims

1. 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, the method comprising:

(a) providing a driving voltage to the primary inductive coil at an initial transmission frequency f_t;

(b) inducing a secondary voltage in the secondary inductive coil;

(c) monitoring power received by the electric load;

(d) sending a control signal when the monitored power deviates from a predetermined range, the control signal including a feedback signal indicating if more or less power is required;

(e) the driver receiving the control signal;

(f) the driver adjusting the driving voltage according to the control signal; and

(g) repeating steps (b) to (f).

2. The method of claim 1 wherein step (d) comprises:

sending a feedback signal of a first type to the driver, whenever the power drops below a first threshold, and

sending a feedback signal of a second type to the driver, whenever the power exceeds a second threshold.

3. The method of claim 1 wherein the initial transmission frequency f_t is higher than the resonant frequency f_R.

4. The method of claim 3 wherein step (f) of adjusting the driving voltage according to the control signal comprises:

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

the driver increasing the transmission frequency by an incremental value when the received feedback signal is of a second type.

5. The method of claim 1 wherein step (f) further comprises:

the driver increasing power by an incremental value when the received feedback signal is of a first type, and

the driver reducing power by an incremental value when the received feedback signal is of a second type.

6. The method of claim 1 wherein step (f) further comprises altering the duty cycle of the driving voltage.

7. The method of claim 1 wherein step (f) further comprises altering the amplitude of the driving voltage.

8. The method of claim 1 wherein the control signals are transferred concurrently with uninterrupted inductive power transfer.

9. An inductive power outlet for providing power to an electric load via an inductive power receiver, the inductive power outlet comprising at least one primary inductive coil wired to a power supply via a driver configured to provide a driving voltage across the primary inductive coil such that a secondary voltage is induced in a secondary inductive coil associated with the inductive power receiver;

wherein the driver comprises a controller configured to receive feedback control signals from the inductive power receiver indicating if more or less power is required, and the controller is further configured to adjust the driving voltage according to the control signals.

10. The inductive power outlet of claim 9 wherein the driver comprises a signal detector configured to detect a first signal and a second signal, and the driver is configured to:

increase power by an incremental value when the first signal is detected by the detector, and

decrease power by an incremental value when the second signal is detected by the detector.

11. The inductive power outlet of claim 9 wherein the driving voltage oscillates at a frequency higher than the resonant frequency.

12. The inductive power outlet of claim 11 wherein the driver comprises a signal detector configured to detect a first signal and a second signal, and the driver is configured to:

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

increase the transmission frequency when the second signal is detected by the detector.

13. The inductive power outlet of claim 9 wherein the primary inductive coil is further wired to a reception circuit comprising a voltage monitor for monitoring the amplitude of the driving voltage across the primary coil.

14. The inductive power outlet of claim 9 wherein the driver is further configured to alter the duty cycle of the driving voltage in response to the simple feedback control signals.

15. The inductive power outlet of claim 9 wherein the driver is further configured to alter the amplitude of the driving voltage in response to the simple feedback control signals.

16. The inductive power outlet of claim 9 wherein the driver is further configured to receive control signals concurrently with uninterrupted inductive power transfer.

17. A signal transmission circuit for an inductive power receiver configured to provide energy to an electric load, the inductive power receiver comprising:

at least one secondary inductive coil for forming an inductive couple with at least one primary inductive coil of an inductive power outlet, the inductive power outlet further comprising at least one driver configured to provide an oscillating driving voltage across the primary inductive coil;

wherein;

the signal transmission circuit comprises at least one power monitor operable to monitor power received by the electric load, and

the signal transmission circuit is operable to send at least one simple feedback signal indicating if more or less power is required.

18. The signal transmission circuit of claim 17 wherein further comprising:

at least one electrical element selected such that a detectable change occurs when the electrical element is connected to the secondary coil; and

at least one switch configured to connect the electrical element to the secondary coil thereby causing a detectable signal pulse in the driving voltage such that the at least one simple feedback signal is received by the inductive power outlet.

19. The signal transmission circuit of claim 17 configured to send

a feedback signal of a first type to the driver, whenever the power drops below a first threshold, and

a feedback signal of a second type to the driver, whenever the power exceeds a second threshold.

20. The signal transmission circuit of claim 17 further configured to send control signals concurrently with uninterrupted inductive power transfer.