WIRELESS POWER TRANSFER DEVICE AND WIRELESS POWER TRANSFER SYSTEM

• US 20160329752A1
• Filed: 01/07/2015
• Published: 11/10/2016
• Est. Priority Date: 01/08/2014
• Status: Active Grant

• Current Assignee: Nera Innovations Limited (Atlantic IP Services Limited)
• Original Assignee: LG Innotek Company Limited (LG Corporation)
• Inventors: BAE, Su Ho
• Granted Patent: US 10,193,392 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 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: H04B 5/24 Inductive coupling
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

A wireless power transfer system according to an embodiment of the present invention is a wireless power transfer system having a receiving part for receiving power from a transmitting part, wherein the transmitting part comprises: a power conversion part comprising a full bridge inverter; and a control part for controlling the power conversion part using a pulse width modulation (PWM) control signal, the duty ratio of the PWM control signal being determined by a duty ratio in which the ratio of the magnitude of harmonics to the magnitude of a fundamental frequency among frequency components of the output signal of the power conversion part is a minimum.

Claims

1. A transmitter for generating a wireless power to be transmitted to a receiver, the transmitter comprising:

a power conversion part comprising a full bridge inverter; and

a control part for controlling the power conversion part using a pulse width modulation (PWM) control signal,

wherein a duty ratio of the PWM control signal is determined by a duty ratio in which a ratio of the magnitude of an harmonic to the magnitude of a fundamental frequency among frequency components of an output signal of the power conversion part is a minimum.

2. The transmitter of claim 1, wherein the harmonic has the maximum magnitude of a plurality of harmonic components that have frequencies of the output signal different with one another.

3. The transmitter of claim 2, wherein the duty ratio is 26% to 44%.

4. The transmitter of claim 2, wherein the duty ratio is 41% or 32%.

5. The transmitter of claim 2, further comprising:

a rectifying and filtering part configured to receive an input AC power and to generate a DC voltage;

a DC/DC converter for regulating a level of the DC voltage outputted from the rectifying and filtering part to be outputted to the power conversion part; and

a matching part for performing an impedance matching between the transmitter and the receiver,

wherein the control part controls a DC voltage level of the DC/DC converter.

6. A method for driving a wireless power transfer system that includes a transmitter having a power conversion part to convert power applied from an external power supply and a receiver to receive power from the transmitter, the method comprising:

allowing, when the receiver approaches a charging region of the transmitter, one of the transmitter and the receiver to sense the other one;

allowing the receiver to request the transmitter to transfer power

allowing a control part of the transmitter to regulate a DC voltage level of the DC/DC converter depending on the amount of power requested by the receiver; and

allowing the control part to control the power conversion part depending on a duty ratio of a predetermined PWM control signal,

wherein the duty ratio of the PWM control signal is determined by a duty ratio in which a ratio of the magnitude of an harmonic to the magnitude of a fundamental frequency among frequency components of an output signal of the power conversion part is a minimum.

7. The method of claim 6, wherein the harmonic has the maximum magnitude of a plurality of harmonic components that have frequencies of the output signal different with one another.

8. The method of claim 7, wherein the power conversion part includes a full bridge inverter that receives a DC voltage from a DC/DC converter to output an AC signal.

9. The method of claim 7, wherein the duty ratio is 26% to 44%.

10. The method of claim 7, wherein the duty ratio is 41% or 32%.

11. The method of claim 6, wherein the control part is fed back with an output signal outputted from the power conversion part and provides the power conversion part with a PWM control signal having a duty ratio in which a ratio of the magnitude of an harmonic to the magnitude of a fundamental frequency of the output signal is a minimum.

12. A transmitter for generating a wireless power to be transmitted to a receiver, the transmitter comprising:

a control part for generating first to fourth AC power control signals; and

a power conversion part for generating an AC power including a positive polarity electrode voltage and a negative polarity electrode voltage in response to the first to fourth AC power control signals,

wherein the power conversion part generates the positive polarity electrode voltage in response to the first and fourth AC power control signals, and the negative polarity electrode voltage in response to the second and third AC power control signals.

13. The transmitter of claim 12, wherein a duty ratio of the positive polarity electrode voltage is determined by a falling time of the fourth AC power control signal,

wherein a duty ratio of the negative polarity electrode voltage is determined by a falling time of the third AC power control signal.

14. The transmitter of claim 13, wherein the duty ratio is regulated depending on a power receiving status of the receiver.

15. The transmitter of claim 14, wherein the falling time of the fourth AC power control signal is ahead of the falling time of the first AC power control signal.

16. The transmitter of claim 12, wherein the falling time of the third AC power control signal is ahead of the falling time of the second AC power control signal.

17. The transmitter of claim 13, wherein the maximum AC power is generated when the duty ratio is 50%,

wherein the magnitude of the AC power is reduced when the duty ratio is decreased.

18. The transmitter of claim 12, wherein the power conversion part includes first to fourth switching elements,

wherein the second and third switching elements are turned off in a time interval when the first and fourth switching elements are turned on,

wherein the first and fourth switching elements are turned off in a time interval when the second and third switching elements are turned on.