Wirelessly Powered Electric Motor

• US 20150256115A1
• Filed: 03/06/2014
• Published: 09/10/2015
• Est. Priority Date: 03/06/2014
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Zeng, Peng, Tillotson, Brian J.
• Granted Patent: US 9,806,658 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02P 25/16 characterised by the circuit arrangement or by the kind of wiring
• CPC Class Codes: H02P 27/04 using variable-frequency supply voltage, e.g. inverter or converter supply voltage
• CPC Class Codes: H04B 5/24 Inductive coupling
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

A method and apparatus for controlling an electric motor. Power is transmitted to windings of the electric motor by wireless magnetic coupling between transmission coils and the windings.

Claims

1. A method of controlling an electric motor, comprising:

transmitting power to windings of the electric motor by wireless magnetic coupling between transmission coils and the windings.

2. The method of claim 1 further comprising:

transmitting the power to the windings at resonant frequencies of the windings.

3. The method of claim 2 further comprising:

transmitting the power to the windings at a first frequency corresponding to a resonant frequency of first windings of the electric motor;

transmitting the power to the windings at a second frequency corresponding to a resonant frequency of second windings of the electric motor; and

wherein the first frequency and the second frequency are different frequencies.

4. The method of claim 3, wherein the first frequency and the second frequency are not harmonics of each other.

5. The method of claim 1 further comprising:

identifying a position of a rotor of the electric motor by identifying an effect of the position of the rotor on inductance of the transmission coils; and

controlling timing of transmitting the power by the transmission coils in response to the position of the rotor.

6. The method of claim 1 further comprising:

identifying movement of a rotor of the electric motor by identifying an effect of the movement of the rotor on power drawn by the transmission coils; and

controlling timing of transmitting the power by the transmission coils in response to the movement of the rotor.

7. An electric motor, comprising:

a rotor; and

a plurality of windings, wherein each of the plurality of windings has a different resonant frequency.

8. The electric motor of claim 7, wherein resonant frequencies for the plurality of windings are not harmonics of each other.

9. The electric motor of claim 7, wherein resonant frequencies for the plurality of windings are different from each other by more than a bandwidth of a resonant peak for the each of the plurality of windings.

10. The electric motor of claim 7, wherein a resonant frequency of a one of the windings in the plurality of windings matches a frequency of a wireless transmission of power to the electric motor.

11. The electric motor of claim 10 further comprising a capacitor connected to the one of the windings, wherein a capacitance of the capacitor is selected such that the resonant frequency of the one of the windings matches the frequency of the wireless transmission of power to the electric motor.

12. The electric motor of claim 11, wherein the capacitor connected to the one of the windings comprises a variable capacitor configured to change the capacitance connected to the one of the windings in response to a position of the rotor to maintain the resonant frequency of the one of the windings constant when an inductance of the one of the windings changes in response to movement of the rotor.

13. An apparatus, comprising:

a power transmitter configured to transmit power to windings of an electric motor by wireless magnetic coupling to the windings; and

a controller configured to control the power transmitter to control timing of transmitting the power to the windings.

14. The apparatus of claim 13, wherein the power transmitter is configured to transmit the power to the windings at a plurality of different frequencies corresponding to resonant frequencies of the windings.

15. The apparatus of claim 14, wherein the plurality of different frequencies are not harmonics of each other.

16. The apparatus of claim 14, wherein the power transmitter comprises:

a first transmission coil having a first resonant frequency corresponding to a resonant frequency of first windings of the electric motor;

a second transmission coil having a second resonant frequency corresponding to a resonant frequency of second windings of the electric motor; and

wherein the first resonant frequency and the second resonant frequency are different frequencies.

17. The apparatus of claim 16, wherein the first resonant frequency and the second resonant frequency are different from each other by more than a bandwidth of a resonant peak for each of the first transmission coil and the second transmission coil.

18. The apparatus of claim 14, wherein:

the power transmitter comprises a transmission coil having an adjustable resonant frequency; and

the controller is configured to adjust the adjustable resonant frequency of the transmission coil to match the resonant frequencies of the windings.

19. The apparatus of claim 13, wherein the controller is configured to:

identify a position of a rotor of the electric motor by identifying an effect of the position of the rotor on an inductance of the power transmitter; and

control the timing of transmitting the power to the windings in response to the position of the rotor.

20. The apparatus of claim 13, wherein the controller is configured to:

identify movement of a rotor of the electric motor by identifying an effect of the movement of the rotor on power drawn by the power transmitter; and

control the timing of transmitting the power to the windings in response to the movement of the rotor.