Power control method and device in wireless power transmission system

1. A wireless power reception device comprising:

at least one secondary coil configured to receive wireless power from a wireless power transmission device;

a control unit configured to generate power control information for controlling an amount of wireless power from the wireless power transmission device; and

a communication unit configured to:

receive, from the wireless power transmission device, a data packet message including a request for information from the wireless power reception device;

communicate the information to the wireless power transmission device in response to the request, and

communicate the power control information to the wireless power transmission device during a power transfer phase.

2. The wireless power reception device of claim 1 , wherein the power control information includes a control error packet (CEP) including a control error value.

3. The wireless power reception device of claim 2 , wherein the CEP includes a header of 1 byte, a message of 1 byte including the control error value, and a checksum field of 1 byte.

4. The wireless power reception device of claim 2 , wherein the control unit is further configured to:

measure an actual control point of the wireless power received by the wireless power reception device; and

calculate the control error value based on a difference between a desired control point and an actual control point.

5. The wireless power reception device of claim 4 , wherein the control unit is further configured to select the desired control point based on a characteristic of the wireless power reception device.

6. The wireless power reception device of claim 5 , wherein the desired control point comprises at least one of a current, voltage, or a temperature of the wireless power reception device.

7. The wireless power reception device of claim 2 , wherein the communication unit is configured to periodically transmit a new CEP to the wireless power transmission device during the power transfer phase.

8. The wireless power reception device of claim 2 , wherein the communication unit is configured to transmit a new CEP to the wireless power transmission device before expiration of a CEP timer for maintaining a wireless power transfer session.

9. The wireless power reception device of claim 2 , wherein the control unit is configured to generate the CEP and cause the communication unit to communicate the CEP within a predetermined time period in a power transmission phase.

10. The wireless power reception device of claim 1 , further comprising:

a power pickup unit configured to collect power received by the secondary coil and provide power to a load, wherein power control information is based, at least in part, on a load state of the load.

11. The wireless power reception device of claim 1 , wherein the communication unit is includes a radio frequency (RF) communication unit.

12. The wireless power reception device of claim 1 , wherein the control unit is further configured to:

monitor parameters of the wireless power received by the at least one secondary coil; and

cause the wireless power transmission device to abort transmission of the wireless power when a parameters exceeds a limit.

13. The wireless power reception device of claim 1 , wherein:

the at least one secondary coil is further configured to provide the wireless power to a load of the wireless power reception device; and

the control unit is further configured to monitor the load and cause the communication unit to transmit a signal requesting the wireless power transmission device to cease transmission of the wireless power based on a condition of the load.

14. A method performed by a wireless power reception device, the method comprising:

receiving wireless power from a wireless power transmission device via at least one secondary coil of the wireless power reception device;

generating, by a control unit of the wireless power reception device, power control information for controlling an amount of wireless power from the wireless power transmission device;

receiving, from the wireless power transmission device by a communication unit, a data packet message including a request for information from the wireless power reception device; and

communicating, by the communication unit, the information to the wireless power transmission device in response to the request; and

communicating, by the communication unit, the power control information to the wireless power transmission device during a power transfer phase.

15. The method of claim 14 , wherein the power control information includes a control error packet (CEP) including a control error value.

16. The method of claim 15 , further comprising:

measuring an actual control point of the wireless power received by the wireless power reception device; and

calculating the control error value based on a difference between a desired control point and an actual control point.

17. The method of claim 15 , further comprising:

periodically transmitting a new CEP to the wireless power transmission device before expiration of a CEP timer during a power transfer phase.

18. The method of claim 14 , wherein receiving the data packet message includes:

receiving the data packet message via the communication unit coupled to the secondary coil or the communication unit being part of a radio frequency (RF) communication unit.

19. The method of claim 14 , further comprising:

monitoring parameters of the wireless power received by the at least one secondary coil; and

causing the wireless power transmission device to abort transmission of the wireless power when a parameters exceeds a limit.

20. The method of claim 14 , further comprising:

providing the wireless power to a load of the wireless power reception device;

monitoring the load; and

transmitting a signal requesting the wireless power transmission device to cease transmission of the wireless power based on a condition of the load.