Inductive power transfer using a relay coil

• US 9,281,720 B2
• Filed: 05/31/2013
• Issued: 03/08/2016
• Est. Priority Date: 05/31/2013
• Status: Active Grant

• Current Assignee: ConvenientPower HK Limited
• Original Assignee: ConvenientPower HK Limited
• Inventors: Liu, Xun
• Primary Examiner(s): WILLIAMS, ARUN C
• Application Number:
  US13/907,483
• Publication Number:
  US 20140354220A1
• Time in Patent Office: 1,012 Days
• Field of Search: 320/108
• US Class Current: 1/1
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/50 using additional energy repeaters between transmitting devices and receiving devices

Abstract

A wireless power charging system includes an intermediate relay coil. In one aspect, a wireless power charging system is designed to charge a separate device having a receiver that includes a receiver coil. The separate device conforms to a specification for the wireless power charging system, which may be a public standard for wireless power charging systems. The wireless power charging system includes a transmitter and a relay coil resonator. The transmitter includes a driver coil that is driven by a power source. The relay coil resonator includes a relay coil that is used to inductively couple power from the driver coil to the receiver coil. The wireless power charging system is designed so that it satisfies Eqn. (11) above.

Claims

1. A wireless power charging system for charging a separate device having a receiver that includes a receiver coil, the separate device conforming to a specification for the wireless power charging system, the wireless power charging system comprising:

a transmitter including a driver coil configured to be driven by a power source; and

a relay coil resonator including a relay coil configured for relaying power by inductive coupling from the driver coil to the receiver coil;

wherein

2. The wireless power charging system of claim 1 wherein a current in the driver coil is less than a current in a transmitter coil of a 2-coil wireless power charging system in which the transmitter coil relays a same amount of power directly to the receiver coil.

3. The wireless power charging system of claim 2 wherein the lower current in the driver coil results in a lower current stress and/or a lower conduction or switching power loss in electronics driving the driver coil, compared to electronics driving the transmitter coil in the 2-coil wireless power charging system.

4. The wireless power charging system of claim 1 wherein the wireless power charging system is capable of charging the separate device at a separation of greater than 3 cm.

5. The wireless power charging system of claim 1 wherein the relay coil is fixed to one side of a support structure and the separate device is placed on a surface of another side of the support structure.

6. The wireless power charging system of claim 1 wherein the relay coil is fixed to a bottom side of a support structure and the separate device is placed on a top surface of the support structure.

7. The wireless power charging system of claim 1 wherein the driver coil and the relay coil are coplanar.

8. The wireless power charging system of claim 7 wherein the driver coil is positioned inside the relay coil.

9. The wireless power charging system of claim 7 wherein the relay coil is positioned inside the driver coil.

10. The wireless power charging system of claim 1 wherein the driver coil and the relay coil are not coplanar, and the relay coil is positioned between the driver coil and the receiver coil.

11. The wireless power charging system of claim 1 wherein the power charging system is part of a permanently-located charging station.

12. The wireless power charging system of claim 1 wherein the power charging system is part of a wireless charging table.

13. The wireless power charging system of claim 1 wherein the power charging system is capable of charging an electric vehicle.

14. The wireless power charging system of claim 1 wherein the specification for the wireless power charging system is a public standard for wireless power charging systems.