Wireless power transfer method, apparatus and system

1. A communication method of a wireless power transmitter for transferring power in a wireless manner, the communication method comprising:

allocating a slot among a plurality of slots to a first wireless power receiver, the slot being allocated to the first wireless power receiver for acquiring information of the first wireless power receiver while wireless power is transferred to the first wireless power receiver;

transferring the wireless power to the first wireless power receiver by the wireless power transmitter;

detecting a second wireless power receiver by the wireless power transmitter during the wireless power transfer to the first wireless power receiver; and

generating a collision related signal based on a frequency shift keying (FSK) such that a collision resolution mechanism is executed by each of the first and second wireless power receivers respectively when first information generated by the first wireless power receiver and second information generated by the second wireless power receiver are in a collision within a first unallocated slot among the plurality of slots, the first information and the second information being generated based on a load modulation.

2. The communication method of claim 1 , wherein the first information includes at least one of an End Power Transfer packet (EPT) or a Charge Status packet (CHS), and

wherein the collision resolution mechanism is executed in a manner that the wireless power transmitter acquires the first information after a first time and acquires the second information after a second time.

3. The communication method of claim 2 , wherein the first time and the second time are randomly defined.

4. The communication method of claim 1 , further comprising:

performing a power contract with the second wireless power receiver when there is no collision between the first information and the second information within the first unallocated slot among the plurality of slots.

5. The communication method of claim 1 , wherein the wireless power transmitter acquires the first information within a second slot among the plurality of slots from the first wireless power receiver subsequent to executing the collision resolution mechanism.

6. The communication method of claim 5 , wherein the wireless power transmitter generates an acknowledge (ACK) signal when the second slot is allocatable and generates a not-acknowledge (NAK) signal when the second slot is in a non-allocatable state.

7. The communication method of claim 5 , wherein the second slot is allocated to the first wireless power receiver when the first information is received within the second slot.

8. A wireless power transmitter for transferring power in a wireless manner, the wireless power transmitter comprising:

a power transmission unit configured to transfer power in a wireless manner; and

a power transmission controller configured to:

allocate a slot among a plurality of slots to a first wireless power receiver, wherein the slot is allocated to the first wireless power receiver for acquiring information of the first wireless power receiver while wireless power is transferred to the first wireless power receiver using the power transmission unit,

detect a second wireless power receiver during the wireless power transfer to the first wireless power receiver, and

generate a collision related signal based on a frequency shift keying (FSK) such that a collision resolution mechanism is executed by each of the first and second wireless power receivers respectively when first information generated by the first wireless power receiver and second information generated by the second wireless power receiver are in a collision within a first unallocated slot among the plurality of slots, the first information and the second information being generated based on a load modulation.

9. The wireless power transmitter of claim 8 , wherein the first information includes at least one of an End Power Transfer packet (EPT) or a Charge Status packet (CHS), and

wherein the collision resolution mechanism is executed in a manner that the power transmission controller acquires the first information after a first time and acquires the second information after a second time.

10. The wireless power transmitter of claim 9 , wherein the first time and the second time are randomly defined.

11. The wireless power transmitter of claim 8 , wherein the power transmission controller performs a power contract with the second wireless power receiver when there is no collision between the first information and the second information within the first unallocated slot among the plurality of slots.

12. The wireless power transmitter of claim 8 , wherein the power transmission controller acquires the first information within a second slot among the plurality of slots from the first wireless power receiver subsequent to executing the collision resolution mechanism.

13. The wireless power transmitter of claim 12 , wherein power transmission controller generates an acknowledge (ACK) signal when the second slot is allocatable and generates a not-acknowledge (NAK) signal when the second slot is in a non-allocatable state.