Efficiency monitor for inductive power transmission

• US 8,090,550 B2
• Filed: 09/21/2009
• Issued: 01/03/2012
• Est. Priority Date: 03/22/2007
• Status: Active Grant

• Current Assignee: Powermat Technologies, Ltd.
• Original Assignee: Powermat Ltd.
• Inventors: Azancot, Yossi, Ben-Shalom, Amir, Greenwald, Oola, Rofe, Arik
• Primary Examiner(s): TSAI, CAROL S W
• Application Number:
  US12/563,558
• Publication Number:
  US 20100070219A1
• Time in Patent Office: 834 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 delivered to the primary coil;

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

at least one processor for determining an index of power-loss; and

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

wherein;

the output power monitor is incorporated into an inductive power receiver unit comprising 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; and

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.

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 signal transmitter is selected from a group consisting of:

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

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

6. The efficiency monitor of claim 5 wherein the hazard detectors are selected from a group consisting of:

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

7. The efficiency monitor of claim 1 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.

8. 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 by the secondary coil, and

at least one signal transmitter configured to transmit signals carrying data pertaining to the output power to an efficiency monitor;

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.

9. The inductive power receiver of claim 8 wherein the signal transmitter is selected from a group consisting of:

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

10. The inductive power receiver of claim 8 wherein the output power monitor is incorporated into an electric device.

11. The inductive power receiver of claim 10 wherein the electric device is selected from a group consisting of:

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