Harmonic Reduction Apparatus for Wireless Power Transfer Systems

• US 20150194811A1
• Filed: 01/06/2015
• Published: 07/09/2015
• Est. Priority Date: 01/07/2014
• Status: Active Grant

• Current Assignee: Quanten Technologies Limited
• Original Assignee: NuVolta Technologies, Inc.
• Inventors: Mao, Hengchun
• Granted Patent: US 9,991,779 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 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: H02M 1/12 Arrangements for reducing harmonics from ac input or output
• CPC Class Codes: H02M 3/33523 with galvanic isolation between input and output of both the power stage and the feedback loop
• 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

A device comprises a switch network coupled to a power source, wherein the switch network comprises a plurality of power switches, a transmitter resonant tank coupled to the plurality of power switches, wherein the transmitter resonant tank comprises a primary resonant capacitor, a transmitter coil coupled to the transmitter resonant tank and a harmonic reduction apparatus coupled between the switch network and the transmitter coil, wherein the harmonic reduction apparatus is configured to attenuate at least one undesired frequency component.

Claims

1. A system comprising:

a switch network coupled to a power source, wherein the switch network comprises a plurality of power switches;

a primary resonant tank coupled to the plurality of power switches, wherein the primary resonant tank comprises at least a resonant capacitor;

a transmitter coil coupled to the primary resonant tank, wherein;

the transmitter coil is configured to be magnetically coupled to a receiver coil; and

the transmitter coil and receiver coil are configured such that wireless power is transferred from the transmitter coil to the receiver coil; and

a harmonic reduction apparatus coupled between the switch network and the transmitter coil, wherein the harmonic reduction apparatus is configured to;

attenuate at least one undesired frequency component of a current in the transmitter coil.

2. The system of claim 1, wherein the harmonic reduction apparatus comprises:

a first harmonic notch circuit comprising a first inductor and a first capacitor connected in series.

3. The system of claim 2, wherein:

the harmonic notch circuit is coupled to the transmitter coil.

4. The system of claim 2, wherein:

the harmonic notch circuit is connected across the primary resonant tank.

5. The system of claim 2, wherein:

the harmonic notch circuit is coupled between the switch network and a node inside the primary resonant tank.

6. The system of claim 2, further comprising:

a second harmonic notch circuit comprising a second inductor and a second capacitor connected in series, wherein the first harmonic notch circuit and the second harmonic notch circuit are connected in parallel, and wherein;

the first inductor and the first capacitor are configured to attenuate a first undesired frequency component; and

the second inductor and the second capacitor are configured to attenuate a second undesired frequency component.

7. The system of claim 1, wherein the harmonic reduction apparatus comprises:

a first harmonic trap circuit comprising a third inductor and a third capacitor connected in parallel.

8. The system of claim 7, wherein:

the harmonic trap circuit is connected in series with the transmitter coil.

9. The system of claim 7, wherein:

the harmonic trap circuit is connected in series with the primary resonant tank.

10. The system of claim 7, wherein:

the harmonic trap circuit is coupled between the switch network and a node inside the primary resonant tank.

11. The system of claim 7, further comprising:

a second harmonic trap circuit comprising a fourth inductor and a fourth capacitor connected in parallel, wherein the first harmonic trap circuit and the second harmonic trap circuit are connected in series, and wherein;

the third inductor and the third capacitor are configured to attenuate a third undesired frequency component; and

the fourth inductor and the fourth capacitor are configured to attenuate a fourth undesired frequency component.

12. The system of claim 1, wherein the harmonic reduction apparatus comprises:

a first series harmonic reduction device and a first parallel harmonic reduction device, and wherein;

the first series harmonic reduction device is coupled between the switch network and the primary resonant tank; and

the first parallel harmonic reduction device is coupled between a common node of the first series harmonic reduction device and the switch network, and a common node of the primary resonant tank and the switch network.

13. The system of claim 1, wherein the harmonic reduction apparatus comprises:

a first series harmonic reduction device and a first parallel harmonic reduction device, and wherein;

the first series harmonic reduction device is coupled between the switch network and the primary resonant tank; and

the first parallel harmonic reduction device is coupled between a common node of the first series harmonic reduction device and the switch network, and a node inside the primary resonant tank.

14. The system of claim 1, wherein the harmonic reduction apparatus comprises:

a first series harmonic reduction device and a first parallel harmonic reduction device, and wherein;

the first series harmonic reduction device is coupled between the switch network and the primary resonant tank; and

the first parallel harmonic reduction device is connected in parallel with the transmitter coil.

15. The system of claim 1, wherein the harmonic reduction apparatus comprises:

a first series harmonic reduction device and a first parallel harmonic reduction device, and wherein;

the first series harmonic reduction device is coupled between the first parallel harmonic reduction device and the primary resonant tank; and

the first parallel harmonic reduction device is coupled to a common node of an impedance circuit and the switch network.

16. A device comprising:

a switch network coupled to a power source, wherein the switch network comprises a plurality of power switches;

a transmitter resonant tank coupled to the plurality of power switches, wherein the transmitter resonant tank comprises a primary resonant capacitor;

a transmitter coil coupled to the transmitter resonant tank; and

a harmonic reduction apparatus coupled between the switch network and the transmitter coil, wherein the harmonic reduction apparatus is configured to attenuate at least one undesired frequency component of a current in the transmitter coil.

17. The device of claim 16, wherein:

the harmonic reduction apparatus comprises a plurality of harmonic trap circuits.

18. The device of claim 16, wherein:

the harmonic reduction apparatus comprises a plurality of harmonic notch circuits.

19. A device comprising:

a switch network coupled to a power source through an input capacitor, wherein the switch network comprises a plurality of power switches;

a transmitter resonant tank coupled to the plurality of power switches, wherein the transmitter resonant tank comprises a primary resonant capacitor;

a transmitter coil coupled to the transmitter resonant tank for transferring power to a receiver coil;

a harmonic reduction apparatus comprising a plurality of harmonic notch circuits and a plurality of harmonic trap circuits; and

a soft start switch coupled between the power source and the input capacitor.

20. The device of claim 19, wherein:

the soft start switch is configured to damp the resonance of the transmitter resonant tank and the harmonic reduction apparatus during a start-up process; and

the soft start switch is controlled by a feedback signal generated based upon a drain voltage of the soft start switch.