System and method for providing simple feedback signals indicating if more or less power is required during inductive power transmission

• US 9,035,501 B2
• Filed: 05/20/2014
• Issued: 05/19/2015
• 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
• Primary Examiner(s): Fleming, Fritz M
• Application Number:
  US14/283,182
• Publication Number:
  US 20140252871A1
• Time in Patent Office: 364 Days
• Field of Search: 307/104, 320/108
• 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

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 an inductive power outlet to an inductive power receiver, the inductive power outlet including a primary inductive coil wired to a power supply via a driver, and the inductive power receiver including a secondary inductive coil wired to an electric load, the method comprising:

providing a driving voltage to the primary inductive coil thereby;

inducing a secondary voltage in the secondary inductive coil;

the driver receiving simple feedback control signals from the inductive power receiver; and

the driver responding to the simple feedback control signals by;

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

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

2. The method of claim 1 further comprising:

the inductive power receiver monitoring power received by the electric load;

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

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

3. The method of claim 1 wherein the driving voltage has an initial transmission frequency f_t higher than the resonant frequency f_R.

4. The method of claim 3 wherein the driver adjusts the driving voltage by:

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

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

5. The method of claim 1 wherein the driver adjusts driving voltage by altering the duty cycle of the driving voltage.

6. The method of claim 1 wherein the driver adjusts driving voltage by altering the amplitude of the driving voltage.

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

8. A signal receiving circuit for an inductive power outlet configured to provide power to an electric load via an inductive power receiver, the inductive power outlet including 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 signal receiving circuit comprises;

a voltage monitor for monitoring the amplitude of the driving voltage across the primary coil;

a controller configured to receive simple feedback control signals of at least a first type and a second type from the inductive power receiver, wherein;

the first type of feedback control signal is selected by the inductive power receiver when more power is required, and

the second type of feedback control signal is selected by the inductive power receiver when less power is required,

and the controller is further configured to adjust the driving voltage according to the feedback control signals.

9. The inductive power outlet of claim 8 wherein the driver comprises a signal detector configured to detect the first type of feedback control signal and the second type of feedback control signal, and the driver is configured to:

increase power by an incremental value when the first type of feedback control signal is detected by the detector, and

decrease power by an incremental value when the second type of feedback control signal is detected by the detector.

10. The inductive power outlet of claim 8 wherein the driving voltage oscillates at a frequency higher than the resonant frequency.

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

decrease the transmission frequency when the first type of feedback control signal is detected by the detector, and

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

12. The inductive power outlet of claim 8 wherein the driver is further configured to alter the duty cycle of the driving voltage in response to the simple feedback control signals.

13. The inductive power outlet of claim 8 wherein the driver is further configured to alter the amplitude of the driving voltage in response to the simple feedback control signals.

14. The inductive power outlet of claim 8 wherein the driver is further configured to receive feedback control signals concurrently with uninterrupted inductive power transfer.

15. 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;

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 to the electrical element to the secondary coil thereby causing a detectable signal pulse in the driving voltage such that simple feedback control signals are detectable by the inductive power outlet; and

the signal transmission circuit is operable to send simple feedback control signals of at least a first type and a second type, wherein;

the first type of feedback control signal is selected by the inductive power receiver when more power is required, and

the second type of feedback control signal is selected by the inductive power receiver when less power is required.

16. The signal transmission circuit of claim 15 configured to send

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

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

17. The signal transmission circuit of claim 15 further configured to send feedback control signals concurrently with uninterrupted inductive power transfer.