Wireless power transmission and charging system, and impedance control method thereof

Patent metadata

Field	Value
Publication number	US-9124122-B2
Application number	US-201213471907-A
Country	US
Kind code	B2
Filing date	May 15, 2012
Priority date	May 18, 2011
Publication date	Sep 1, 2015
Grant date	Sep 1, 2015

Abstract

A wireless power transmission and charging system and method are provided. The wireless power may refer to energy that may be transferred from a wireless power transmitter to a wireless power receiver. The wireless power transmission and charging system may include a source device to wirelessly transmit power, and a target device to wirelessly receive power.

First claim

What is claimed is:

1. An impedance control method of a wireless power transmitter configured to transmit power to at least one of target device, the method comprising:
generating power for charging by determining an impedance of a source resonator, and adjusting a voltage level of a direct current (DC) voltage to be supplied to a power amplifier;
transmitting the charging power to the at least one of target device through magnetic coupling; and
adjusting the impedance of the source resonator based on one or more of a reflected wave of the charging power, an amount of power received by each of the at least one of target device, an amount of the charging power, or a transmission efficiency of the charging power.

2. The method of claim 1 , further comprising, prior to generating a charging power:
transmitting a wake-up request message to the at least one of target device;
receiving response messages corresponding to the wake-up request message from the at least one of target device; and
detecting the number of the at least one of target device based on the received response messages.

3. The method of claim 2 , wherein each of the response messages comprises one or more of a product type of a corresponding target device, manufacturer information of the corresponding target device, a product model name of the corresponding target device, a battery type of the corresponding target device, a charging scheme of the corresponding target device, an impedance value of a load of the corresponding target device, information about a characteristic of a target resonator of the corresponding target device, information about a used frequency band of the corresponding target device, an amount of a power to be used for the corresponding target device, an intrinsic identifier of the corresponding target device, and product version information or standards information of the corresponding target device.

4. The method of claim 1 , wherein the adjusting of the impedance of the source resonator is performed by controlling N matching switches to be powered ON and/or OFF, and the N matching switches are connected to a plurality of capacitors and/or a plurality of inductors.

5. The method of claim 4 , wherein the adjusting of the impedance of the source resonator comprises:
calculating a voltage standing wave ratio (VSWR) based on a voltage level of the reflected wave, a level of an output voltage, and a level of an output current of a source resonator;
controlling the N matching switches to be powered ON and OFF, in response to the VSWR being less than a predetermined reference value;
determining a tracking impedance having a power transmission efficiency above a predetermined threshold; and
changing the impedance of the source resonator to the tracking impedance having the power transmission efficiency above the predetermined threshold.

6. The method of claim 5 , wherein the determining of the tracking impedance having the power transmission efficiency above a predetermined threshold comprises performing the following operations a) through g) continuously for each of the N matching switches,
a) selecting at least one of the N matching switches based on a predetermined selection scheme;
b) changing the impedance of the source resonator to a selected impedance, by controlling the at least one selected matching switch to be powered ON;
c) transmitting the charging power;
d) transmitting, to the at least one of target device, a command to request an input voltage value and an input current value of a target device, or a command to request a DC/DC output voltage value and a DC/DC output current value of the target device;
e) receiving, from each of the at least one of target device, an input voltage value and an input current value of a rectification unit, or the DC/DC output voltage value and the DC/DC output current value;
f) calculating an amount of a power received by each of the at least one of target device, based on the input voltage value and the input current value, or the DC/DC output voltage value and the DC/DC output current value; and
g) calculating a transmission efficiency of the charging power, based on an output voltage level and an output current level of the source resonator, and the amount of a power received by each of the at least one of target device.

7. The method of claim 6 , wherein the predetermined selection scheme in the operation a) corresponds to a scheme of selecting matching switches so that the plurality of capacitors may be powered ON and OFF in a sequential order, beginning from a capacitor having a lowest capacitance value to a capacitor having a highest capacitance value, or a scheme of selecting matching switches so that the plurality of capacitors may be powered ON and OFF in a sequential order, beginning from the capacitor having the highest capacitance value to the capacitor having the lowest capacitance value.

8. The method of claim 7 , wherein the predetermined selection scheme in the operation a) corresponds to a scheme of classifying the N matching switches into M groups, selecting one of the M groups based on the number of the one or more target devices, and sequentially selecting tracking frequencies included in the selected group, M being less than N.

9. The method of claim 6 , wherein the predetermined selection scheme in the operation a) corresponds to a scheme of sequentially selecting M matching switches from the N matching switches, performing the operations b) through g) continuously for each of the M matching switches, and subsequently performing the operations b) through g) continuously for each matching switch, excluding the M matching switches from the N matching switches, M being less than N.

10. The method of claim 1 , wherein the generating of the charging power comprises determining the voltage level of the DC voltage to be supplied to the power amplifier based on one or more of a product type of the corresponding target device, a manufacturer information of the corresponding target device, a product model name of the corresponding target device, a battery type of the corresponding target device, a charging scheme of the corresponding target device, an impedance value of the load of the corresponding target device, information about the characteristic of the target resonator of the corresponding target device, information about the used frequency band of the corresponding target device, and an amount of a power to be used for the corresponding target device.

11. The method of claim 1 , wherein the generating of the charging power comprises:
generating power for charging by determining the impedance of a source resonator based on the number of the at least one of target device, and adjusting the voltage level of the direct current (DC) voltage to be supplied to the power amplifier based on the number of the at least one of target device.

12. A wireless power transmitter comprising:
a power converter configured to generate a charging power used for charging in at least one of target device, by converting a direct current (DC) voltage to be supplied to a power amplifier to an alternating current (AC) voltage using a resonance frequency;
a source resonator configured to transmit, to at least one of target device, the generated power through magnetic coupling; and
an impedance adjusting unit configured to adjust an impedance of the source resonator based on one or more of a reflected wave of the charging power, an amount of power received by each of the at least one of target device, an amount of the charging power, or a transmission efficiency of the charging power.

13. The wireless power transmitter of claim 12

Assignees

• Kim Nam Yun
• Kwon Sang Wook
• Park Yun Kwon
• Samsung Electronics Co Ltd

Inventors

• Kim Nam Yun
• Kwon Sang Wook
• Park Yun Kwon

Classifications

• H02J50/80

  involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices · CPC title

• H01F38/14

  Inductive couplings {(for wireless supply or distribution of electric power using inductive coupling H02J50/10)} · CPC title

• Y02T10/7072

  Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors · CPC title

• Y02T90/14

  Plug-in electric vehicles · CPC title

• B60L2210/40

  DC to AC converters · CPC title