Efficiency monitor for inductive power transmission

• US 8,626,461 B2
• Filed: 11/29/2011
• Issued: 01/07/2014
• Est. Priority Date: 03/22/2007
• Status: Active Grant

• Current Assignee: Powermat Technologies, Ltd.
• Original Assignee: Powermat Technologies, Ltd.
• Inventors: Azancot, Yossi, Ben-Shalom, Amir, Greenwald, Oola, Rofe, Arik
• Primary Examiner(s): TSAI, CAROL S W
• Application Number:
  US13/306,379
• Publication Number:
  US 20120071091A1
• Time in Patent Office: 770 Days
• Field of Search: 702/62, 702/150, 324/239, 324/329, 324/334, 324/335, 324/336, 323/224, 323/225, 323/235, 323/238, 323/247, 323/259, 323/262, 363/16, 363/24, 363/25, 363/131, 320/108, 320/109, 320/114, 235/380, 307/104, 307/116, 318/16, 318/480, 318/538
• US Class Current: 702/62
• CPC Class Codes: G01V 3/08 operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices with electromagnetic waves G01V3/12
• 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 50/10 using inductive coupling
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• 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 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00045 Authentication, i.e. circuits for checking compatibility between one component, e.g. a battery or a battery charger, and another component, e.g. a power source
• CPC Class Codes: H02J 7/00309 Overheat or overtemperature protection
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: H02J 7/007192 in response to temperature
• CPC Class Codes: H02M 1/0058 by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826
• CPC Class Codes: H02M 3/3376 with automatic control of output voltage or current
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

An efficiency monitor for monitoring the efficiency of power transmission by an inductive power outlet. The efficiency monitor includes an input power monitor, for measuring the input power delivered to the primary coil, and an output power monitor, for measuring the output power received by the secondary coil. The input and output powers are used by a processor to determine an index of power-loss. A circuit breaker may be used to disconnect the inductive power outlet in case of excessive power loss.

Claims

1. An efficiency monitor for monitoring power transmission by an inductive power outlet, the inductive power outlet comprising at least one primary coil wired to a power supply, for inductively coupling with a secondary coil wired to an electric load, the efficiency monitor comprising:

at least one input power monitor for measuring input power received by the primary coil from the power supply;

at least one output power monitor for measuring output power received inductively by the secondary coil from the primary coil;

at least one processor for determining an index of power-loss indicative of the efficiency of an inductive coupling between the primary coil and the secondary coil; and

at least one communication channel for communicating the input power and the output power to the processor

wherein the index of power-loss comprises at least one of;

an efficiency quotient Q, defined as the ratio of the output power to the input power, and

an efficiency differential Δ

, defined as the difference between the output power and the input power.

2. The efficiency monitor of claim 1 additionally comprising at least one circuit-breaker configured to disconnect the primary coil from the power supply.

3. The efficiency monitor of claim 1 wherein the input power monitor is incorporated into the inductive power outlet.

4. The efficiency monitor of claim 1 wherein the output power monitor is incorporated into an inductive power receiver unit.

5. The efficiency monitor of claim 4 wherein the inductive power receiver unit comprises at least one signal transmitter for transmitting a signal to a receiver incorporated in the power outlet, the signal carrying data pertaining to the output power.

6. The efficiency monitor of claim 5 wherein the signal transmitter is selected from a group consisting of:

light emitting diodes, radio transmitters, optocouplers, and transmitter circuits.

7. The efficiency monitor of claim 5 wherein the transmitter comprises:

an ancillary load selectively connectable to the secondary inductive coil,

a modulator for modulating a bit-rate signal with an input signal to create a modulated signal, and

a switch for intermittently connecting the ancillary load to the secondary inductive coil according to the modulated signal.

8. The efficiency monitor of claim 1 additionally comprising hazard detectors in communication with the processor.

9. The efficiency monitor of claim 8 wherein the hazard detectors are selected from a group consisting of:

magnetic sensors, heat sensors, electromagnetic radiation sensors and Hall probes.

10. A method for monitoring the efficiency of power transmission by an inductive power outlet, the inductive power outlet comprising at least one primary coil wired to a power supply, for inductively coupling with a secondary coil wired to an electric load, the method comprising the steps of:

measuring the input power received by the primary coil from the power supply;

measuring the output power received inductively by the secondary coil from the primary coil;

communicating the input power to a processor;

communicating the output power to the processor; and

the processor determining an index of power-loss indicative of the efficiency of an inductive coupling between the primary coil and the secondary coil;

wherein the index of power-loss comprises at least one of;

an efficiency quotient Q, defined as the ratio of the output power to the input power; and

an efficiency differential Δ

, defined as the difference between the output power and the input power.

11. The method of claim 10, wherein the index of power-loss is the efficiency quotient Q the input power, the method comprising the further step of:

disconnecting the primary coil from the power supply if the efficiency quotient Q is below a threshold value.

12. The method of claim 10, wherein the index of power-loss is the efficiency differential Δ

the method comprising the further step of;

disconnecting the primary coil from the power supply if the efficiency differential Δ

is above a threshold value.

13. An inductive power outlet comprising at least one primary coil, for inductively coupling with a secondary coil wired to an electric load, the inductive power outlet further comprising an efficiency monitor comprising:

at least one input power monitor configured to measure input power received by the primary coil from the power supply;

at least one signal detector configured to detect signals carrying data pertaining to output power received by the secondary coil;

at least one processor configured to receive data pertaining to the input power and the output power, the processor further configured to determine an index of power-loss indicative of the efficiency of an inductive coupling between the primary coil and the secondary coil;

wherein the index of power-loss comprises at least one of;

an efficiency quotient Q, defined as the ratio of the output power to the input power; and

an efficiency differential Δ

, defined as the difference between the output power and the input power.

14. The inductive power outlet of claim 13 additionally comprising at least one circuit-breaker configured to disconnect the primary coil from the power supply.

15. An inductive power receiver comprising at least one secondary coil for inductively coupling to a primary coil and supplying power to an electric load, the inductive power receiver further comprising

at least one output power monitor for measuring output power received inductively by the secondary coil from the primary coil, and

at least one signal transmitter configured to transmit signals carrying data pertaining to the output power to the inductive power outlet of claim 13.

16. The inductive power receiver of claim 15 wherein the signal transmitter is selected from a group consisting of:

light emitting diodes, radio transmitters, optocouplers, and transmitter circuits.

17. The inductive power receiver of claim 15 wherein the transmitter comprises:

an ancillary load selectively connectable to the secondary inductive coil, a modulator for modulating a bit-rate signal with an input signal to create a modulated signal, and

a switch for intermittently connecting the ancillary load to the secondary inductive coil according to the modulated signal.

18. The inductive power receiver of claim 15 wherein the output power monitor is incorporated into an electric device.

19. The inductive power receiver of claim 18 wherein the electric device is selected from a group consisting of:

computers, telephones, personal digital assistance (PDAs), cameras, media players, computers, keyboards and mice.