Wireless charging system and method for controlling the same

1. A wireless charging system, comprising:

an inverter changing a DC voltage applied from a power source module to a pulse voltage signal by a switching operation; and,

a wireless power transmitting module including at least one power transmitter receiving the pulse voltage and transmitting power to at least one power receiver,

wherein the wireless power transmitting module controls the power, which is transmitted to the at least one power receiver depending on required power of the at least one power receiver,

wherein the at least one power transmitter comprises a resonance tank transmitting power to the at least one power receiver, and an enabling switch connected to the resonance tank in series, and a magnitude of a driving voltage as an input of the enabling switch is controlled depending on the required power,

wherein the required power is power to allow a load of the at least one power receiver to be charged up to a targeted voltage gain.

2. The wireless charging system of claim 1 , wherein the wireless power transmitting module further comprises:

a first processor controlling the power transmitted from the power transmitter depending on the required power, and

wherein the first processor controls a voltage of the resonance tank included in the power transmitter to control the power transmitted to the power receiver.

3. The wireless charging system of claim 2 , wherein the first processor determines a frequency of a driving signal of the inverter depending on the required power and controls a switching operation of the inverter based on the driving frequency.

4. The wireless charging system of claim 3 , wherein the number of the power receiver is equal to or more than two, and the first processor detects a maximum power among required powers of the power receivers and determines the frequency of the driving signal for controlling the switching operation of the inverter based on the maximum power.

5. The wireless charging system of claim 1 , wherein

the resonance tank is configured to include a transmitting inductor and a transmitting capacitor which are connected to each other in series.

6. The wireless charging system of claim 1 , wherein the enabling switch is a metal oxide semiconductor field effect transistor (MOSFET).

7. The wireless charging system of claim 2 , wherein the number of the power transmitter is equal to or more than two, the number of the power receiver is equal to or more than two, each of the power transmitters transmits power to one corresponding power receiver of the power receivers, and the first processor controls the voltage of the resonance tank of each of the power transmitters by controlling the magnitude of the driving voltage of the enabling switch of each of the power transmitters depending on the required power of the power receiver corresponding to each of the power transmitters.

8. The wireless charging system of claim 7 , wherein the inverter includes a first switch and a second switch which are electrically connected to each other and are alternately operated, and

the power transmitters are connected to each other in parallel, and the second switch is connected to the power transmitters in parallel.

9. The wireless charging system of claim 8 , wherein the first and second switches are a metal oxide semiconductor field effect transistor (MOSFET).

10. The wireless charging system of claim 8 , wherein the first processor determines a frequency of a PWM signal for controlling an operation of the first switch and the second switch of the inverter based on a maximum power among targeted powers of the power receivers.

11. A method for controlling a wireless charging system including a wireless power transmitting module including an inverter and at least one power transmitter comprising a resonance tank transmitting power to at least one power receiver and an enabling switch connected to the resonance tank in series, comprising:

a required power receiving step of receiving required power of the at least one power receiver;

a driving frequency determining step of determining a frequency of a driving signal of the inverter based on the required power; and

a transmitting power controlling step of controlling power, which is transmitted to the power receiver by controlling a magnitude of a driving voltage as an input of the enabling switch depending on the required power,

wherein the required power is power to allow a load of the at least one power receiver to be charged up to a targeted voltage gain.

12. The method of claim 11 , wherein the number of the power transmitter is equal to or more than two, the number of the power receiver is equal to or more than two, and each of the power transmitters transmits power to one corresponding power receiver of the power receivers,

wherein the transmitting power controlling step controls the magnitude of the driving voltage of the enabling switch of each of the power transmitters depending on required power of the power receiver corresponding to each of the power transmitters.

13. The method of claim 11 , wherein the transmitting power controlling step

continuously performs the voltage control of the driving signal if it is determined that an output power of the power receiver is less than the required power and ending the voltage control of the driving signal if it is determined that the output power of the power receiver is equal to or more than the required power, by comparing between the output power and the required power.

14. The method of claim 11 , wherein the enabling switch is a metal oxide semiconductor field effect transistor (MOSFET).

15. The method of claim 11 , wherein the number of the power receiver is equal to or more than two, the power receivers are connected to each other in parallel, and the inverter applies an input voltage to the power receivers,

wherein the driving frequency determining step includes:

a step of calculating a maximum power among required powers of the power receivers; and

a step of determining the frequency of the driving signal for controlling an operation of a first switch and a second switch of the inverter based on the maximum power.

16. The method of claim 15 , wherein the first and second switches of the inverter are a metal oxide semiconductor field effect transistor (MOSFET), and

the driving signal is a pulse width modulation (PWM) signal for operating the MOSFET.