KR20170140685A - Foreign Object Detection Method and Apparatus and System therefor - Google Patents

Abstract

The present invention relates to a foreign object (FO) detection method for wireless charging, and to an apparatus and a system therefor. According to an embodiment of the present invention, an FO detection method in a wireless power transmitter comprises the following steps of: storing a quality factor value measured in a selection step; determining possibility of existence of an FO in a ping step; as a result of the determination, if it is determined that the possibility of existence of an FO is high, correcting a reference quality factor accuracy set as default; determining a quality factor threshold value for FO detection by using the corrected reference quality factor accuracy; and comparing the determined quality factor threshold value with the measured quality factor value to detect an FO. Therefore, according to the present invention, it is possible to detect an FO more effectively.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a foreign object detecting method,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to wireless power transmission technology, and more particularly, to a method for detecting foreign matter on a wireless charging system and an apparatus and system therefor.

Recently, as the information and communication technology rapidly develops, a ubiquitous society based on information and communication technology is being made.

In order for information communication devices to be connected anytime and anywhere, sensors equipped with a computer chip having a communication function must be installed in all facilities of the society. Therefore, power supply problems of these devices and sensors are becoming a new challenge. In addition, mobile devices such as Bluetooth handsets and iPods, as well as mobile phones, have been rapidly increasing in number, and charging the battery has required users time and effort. As a way to solve this problem, wireless power transmission technology has recently attracted attention.

The wireless power transmission technology (wireless power transmission or wireless energy transfer) is a technology to transmit electric energy from the transmitter to the receiver wirelessly using the induction principle of the magnetic field. In the 1800s, electric motor or transformer And thereafter, a method of transmitting electrical energy by radiating electromagnetic waves such as high frequency, microwave, and laser has also been attempted. Our electric toothbrushes and some wireless shavers are actually charged with electromagnetic induction.

Up to the present, energy transmission using radio may be roughly classified into a magnetic induction method, an electromagnetic resonance method, and an RF transmission method using a short wavelength radio frequency.

In the magnetic induction method, when two coils are adjacent to each other and a current is supplied to one coil, a magnetic flux generated at this time causes an electromotive force to the other coils. As a technology, . The magnetic induction method has the disadvantage that it can transmit power of up to several hundred kilowatts (kW) and the efficiency is high, but the maximum transmission distance is 1 centimeter (cm) or less, so it is usually adjacent to the charger or the floor.

The self-resonance method is characterized by using an electric field or a magnetic field instead of using electromagnetic waves or currents. The self-resonance method is advantageous in that it is safe to other electronic devices or human body since it is hardly influenced by the electromagnetic wave problem. On the other hand, it can be used only at a limited distance and space, and has a disadvantage that energy transfer efficiency is somewhat low.

Short wavelength wireless power transmission - simply, RF transmission - takes advantage of the fact that energy can be transmitted and received directly in radio wave form. This technology is a RF power transmission system using a rectenna. Rectena is a combination of an antenna and a rectifier, which means a device that converts RF power directly into direct current power. That is, the RF method is a technique of converting an AC radio wave into DC and using it. Recently, as the efficiency has improved, commercialization has been actively researched.

Wireless power transmission technology can be applied not only to mobile, but also to various industries such as IT, railroad, and household appliance industry.

If there is a conductor (i.e., a foreign object) other than a wireless power receiver in the wireless rechargeable area, the electromagnetic signal sent from the wireless power transmitter may be induced in the FO to raise the temperature. As an example, the FO may include coins, clips, pins, ballpoint pens, and the like.

If there is an FO between the wireless power receiver and the wireless power transmitter, not only does the wireless charging efficiency drop significantly, but also the temperature of the wireless power receiver and the wireless power transmitter can rise together due to the increase of the FO ambient temperature. If the FO located in the charging area is not removed, not only will power waste be caused, but overheating can cause damage to the wireless power transmitter and the wireless power receiver.

Therefore, detecting the FO located in the charging region has emerged as an important issue in wireless charging technology.

It is an object of the present invention to provide a foreign matter detection method for wireless charging and an apparatus and system therefor.

It is another object of the present invention to provide a wireless power transmission apparatus capable of detecting foreign matter more accurately by adaptively correcting the reference quality factor accuracy based on a determination as to whether there is a foreign substance determined in the ping stage.

Still another object of the present invention is to provide a foreign matter detection method and apparatus therefor that are capable of preventing in advance that FO is not detected by determining a threshold value for foreign object (FO) detection adaptively based on a judgment on the possibility of foreign object presence And a system.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, unless further departing from the spirit and scope of the invention as defined by the appended claims. It will be possible.

The present invention can provide a foreign matter detection method for wireless charging and an apparatus and system therefor.

The method for detecting a foreign substance in a wireless power transmitter according to an embodiment of the present invention includes storing a quality factor value measured in a selection step, determining a possibility of existence of a foreign substance in a pinging step, Determining a quality factor threshold value for detecting a foreign object by using the corrected reference quality factor accuracy; and comparing the determined quality factor threshold value with the default quality factor value, And comparing the measured quality factor value with the measured quality factor value.

The foreign matter detecting method may further include a step of measuring the intensity of the sending current in the pinging step and a step of comparing the intensity of the measured sending current with a predetermined current reference value to determine the possibility of the foreign matter.

In one embodiment, the intensity of the sending current may be the intensity of the current input to the inverter included in the wireless power transmission apparatus.

In another embodiment, the intensity of the sending current may be the intensity of the current flowing in the transmitting coil of the wireless power transmission apparatus.

Also, if it is determined that the possibility of the foreign substance is high, the reference quality factor accuracy set to the default can be corrected to be lowered to a certain level.

In addition, if it is determined that the possibility of the presence of the foreign substance is low, the foreign substance detection method may further include maintaining the reference quality factor accuracy set as the default.

The foreign substance detection method may further include receiving a Foreign Object Detection (FOD) status packet including a reference quality factor value in a negotiation step, wherein the corrected reference quality factor accuracy is applied to the reference quality factor value The quality factor threshold value can be determined.

In addition, the production factor and the measurement error value for considering the design difference of each transmitter may be further applied to the reference quality factor value to determine the quality factor threshold value.

In addition, the production and measurement error values may be constant values determined based on at least one of a power class of the wireless power transmitter, a characteristic of a transmission coil mounted on the wireless power transmitter, and an arrangement structure.

As a result of the comparison, if no foreign object is detected, the ACK packet may be transmitted to the corresponding wireless power receiver and then transitioned to the power transmission step.

As a result of the comparison, if a foreign object is detected, the NACK packet may be transmitted to the corresponding wireless power receiver and then may be entered into the selection step.

The method may further include determining whether the foreign matter is removed based on the intensity of the output current measured while the foreign matter is detected, and if it is determined that the detected foreign matter is not controlled The ping transmission may be delayed for a predetermined time.

According to another aspect of the present invention, there is provided a foreign object detecting apparatus comprising a quality factor measuring unit for measuring a quality factor value for a transmitting coil in a selecting step, a sensing unit for measuring the intensity of a sending current in a pinging step, And a control unit for determining a possibility of foreign matter based on the intensity and correcting a reference quality factor accuracy set as a default when it is determined that a foreign substance is highly likely to be present, The quality factor threshold for detection can be determined.

In addition, if the measured intensity of the sending current is smaller than a predetermined current reference value, the controller can determine that the possibility of the foreign matter is high.

The foreign matter detecting apparatus may further include a DC-DC converter for converting DC power applied from a power source into specific DC power, and an inverter for converting the converted DC power into AC power, The intensity of the current flowing between the DC converter and the inverter.

The foreign matter detecting device may further include an LC resonance circuit composed of a resonance capacitor and an inductor for radiating AC power in a wireless manner, and the intensity of the outgoing current may be an intensity of a current flowing in the inductor.

In addition, if it is determined that the possibility of the foreign substance is high, the controller may correct the reference quality factor accuracy set to the default to a certain level.

Also, if it is determined that the possibility of the presence of the foreign substance is low, the control unit may control to maintain the accuracy of the reference quality factor set as the default.

The foreign substance detection apparatus may further include a demodulation unit for receiving a Foreign Object Detection (FOD) status packet including a reference quality factor value in a negotiation step, wherein the control unit sets the corrected reference quality factor accuracy May be applied to determine the quality factor threshold.

In addition, the production factor and the measurement error value for considering the design difference of each transmitter may be further applied to the reference quality factor value to determine the quality factor threshold value.

Here, the production and measurement error value may be a constant value determined based on at least one of a power class of the wireless power transmitter, a characteristic of a transmission coil mounted on the wireless power transmitter, and an arrangement structure.

As a result of the comparison, if the foreign object is not detected, the controller can control the transition to the power transmission step after transmitting the ACK packet.

As a result of the comparison, when the foreign object is detected, the control unit may control to enter the selection step after transmitting the NACK packet to the corresponding wireless power receiver.

The control unit may determine whether or not the foreign substance is removed based on the intensity of the measured output current in the state where the foreign matter is detected, and if it is determined that the detected foreign matter is not removed, So that transmission can be controlled to be delayed.

According to another embodiment of the present invention, there is provided a computer-readable recording medium having recorded thereon a program for executing any one of the above-mentioned foreign matter detection methods.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, And can be understood and understood.

Effects of the method, apparatus and system according to the present invention will be described as follows.

An advantage of the present invention is to provide a foreign matter detection method for wireless charging and an apparatus and system therefor.

Further, the present invention has an advantage of providing a wireless power transmitter capable of detecting foreign matter more accurately.

In addition, the present invention has the advantage of minimizing unnecessary power consumption and heat generation due to foreign matter.

The effects obtained by the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description will be.

1 is a block diagram illustrating a wireless charging system according to an embodiment of the present invention.
2 is a block diagram illustrating a wireless charging system according to another embodiment of the present invention.
3 is a diagram for explaining a sensing signal transmission procedure in a wireless charging system according to an embodiment of the present invention.
4 is a state transition diagram for explaining the wireless power transmission procedure defined in the WPC standard.
5 is a state transition diagram for explaining a wireless power transmission procedure defined in the WPC (Qi) standard.
6 is a block diagram illustrating a structure of a wireless power transmitter according to an embodiment of the present invention.
7 is a block diagram illustrating a structure of a wireless power receiver interworking with the wireless power transmitter according to the FIG.
8 is a diagram for explaining a modulation and demodulation method of a wireless power signal according to an embodiment of the present invention.
9 is a diagram for explaining a packet format according to an embodiment of the present invention.
FIG. 10 is a view for explaining the types of packets defined in the WPC (Qi) standard according to an embodiment of the present invention.
11 is a block diagram for explaining a structure of a foreign substance detecting apparatus according to an embodiment of the present invention.
12 is a diagram for explaining a message structure of an FOD state packet according to the present invention.
13 is a flowchart illustrating a foreign matter detection method in a wireless power transmission apparatus according to an embodiment of the present invention.
FIG. 14 is a flowchart illustrating an operation of a wireless power transmission apparatus in a state where a foreign object is detected according to an embodiment of the present invention.
FIG. 15 is a flowchart for explaining an FO detection method according to an embodiment of the present invention, in accordance with the possibility of existence of a foreign object.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an apparatus and various methods to which embodiments of the present invention are applied will be described in detail with reference to the drawings. The suffix "module" and " part "for the components used in the following description are given or mixed in consideration of ease of specification, and do not have their own meaning or role.

In the description of the embodiment, in the case where it is described as being formed "above" or "below" each element, the upper or lower (lower) And that at least one further component is formed and arranged between the two components. Also, in the case of "upper (upper) or lower (lower)", it may include not only an upward direction but also a downward direction based on one component.

In the description of the embodiments, an apparatus equipped with a function of transmitting wireless power on a wireless charging system includes a wireless power transmitter, a wireless power transmitter, a wireless power transmitter, a wireless power transmitter, a transmitter, a transmitter, , A transmitting side, a wireless power transmission device, a wireless power transmitter, and the like are used in combination. Further, for the sake of convenience of explanation, it is to be understood that a wireless power receiving apparatus, a wireless power receiving apparatus, a wireless power receiving apparatus, a wireless power receiving apparatus, a receiving terminal, a receiving side, A receiver, a receiver, and the like can be used in combination.

The transmitter according to the present invention may be configured as a pad type, a cradle type, an access point (AP) type, a small base type, a stand type, a ceiling embedded type, a wall type, Power can also be transmitted. To this end, the transmitter may comprise at least one radio power transmission means. Here, the radio power transmitting means may be various non-electric power transmission standards based on an electromagnetic induction method in which a magnetic field is generated in a power transmitting terminal coil and charged using an electromagnetic induction principle in which electricity is induced in a receiving terminal coil under the influence of the magnetic field. Here, the wireless power transmission means may include an electromagnetic induction wireless charging technique defined by Wireless Power Consortium (WPC) and Power Matters Alliance (PMA), which are standard wireless charging technologies.

Also, a receiver according to an embodiment of the present invention may include at least one wireless power receiving means, and may receive wireless power from two or more transmitters at the same time. Here, the wireless power receiving means may include an electromagnetic induction wireless charging technique defined by Wireless Power Consortium (WPC) and Power Matters Alliance (PMA), which are standard wireless charging technologies.

The receiver according to the present invention may be used in a mobile phone, a smart phone, a laptop computer, a digital broadcasting terminal, a PDA (Personal Digital Assistants), a PMP (Portable Multimedia Player), a navigation device, A portable electronic device such as a toothbrush, an electronic tag, a lighting device, a remote control, a fishing rod, a smart watch, etc. However, the present invention is not limited thereto. It suffices.

1 is a block diagram illustrating a wireless charging system according to an embodiment of the present invention.

Referring to FIG. 1, the wireless charging system includes a wireless power transmission terminal 10 for wirelessly transmitting power, a wireless power receiving terminal 20 for receiving the transmitted power, and an electronic device 20 Lt; / RTI >

For example, the wireless power transmitting terminal 10 and the wireless power receiving terminal 20 can perform in-band communication in which information is exchanged using the same frequency band as that used for wireless power transmission. In another example, the wireless power transmitting terminal 10 and the wireless power receiving terminal 20 perform out-of-band communication in which information is exchanged using a different frequency band different from the operating frequency used for wireless power transmission .

For example, information exchanged between the wireless power transmitting terminal 10 and the wireless power receiving terminal 20 may include control information as well as status information of each other. Here, the status information and the control information exchanged between the transmitting and receiving end will become more apparent through the description of the embodiments to be described later.

The in-band communication and the out-of-band communication may provide bidirectional communication, but the present invention is not limited thereto. In another embodiment, the in-band communication and the out-of-band communication may be provided.

 For example, the unidirectional communication may be that the wireless power receiving terminal 20 transmits information only to the wireless power transmitting terminal 10, but the present invention is not limited thereto, and the wireless power transmitting terminal 10 may transmit information Lt; / RTI >

In the half duplex communication mode, bidirectional communication is possible between the wireless power receiving terminal 20 and the wireless power transmitting terminal 10, but information can be transmitted only by any one device at any time.

The wireless power receiving terminal 20 according to an embodiment of the present invention may acquire various status information of the electronic device 30. [ For example, the status information of the electronic device 30 may include current power usage information, information for identifying a running application, CPU usage information, battery charge status information, battery output voltage / current information, And is information obtainable from the electronic device 30 and available for wireless power control.

In particular, the wireless power transmitting terminal 10 according to an embodiment of the present invention can transmit a predetermined packet indicating whether or not to support fast charging to the wireless power receiving terminal 20. The wireless power receiving terminal 20 can inform the electronic device 30 of the connected wireless power transmitting terminal 10 when it is confirmed that it supports the fast charging mode. The electronic device 30 may indicate that fast charging is possible through a predetermined display means, which may be, for example, a liquid crystal display.

Also, the user of the electronic device 30 may select the predetermined fast charge request button displayed on the liquid crystal display means to control the wireless power transmitting terminal 10 to operate in the fast charge mode. In this case, the electronic device 30 can transmit a predetermined fast charge request signal to the wireless power receiving terminal 20 when the quick charge request button is selected by the user. The wireless power receiving terminal 20 may generate a charging mode packet corresponding to the received fast charging request signal and transmit the same to the wireless power transmitting terminal 10 to switch the general low power charging mode to the fast charging mode.

2 is a block diagram illustrating a wireless charging system according to another embodiment of the present invention.

For example, as shown in 200a, the wireless power receiving terminal 20 may include a plurality of wireless power receiving devices, and a plurality of wireless power receiving devices may be connected to one wireless power transmitting terminal 10, Charging may also be performed. At this time, the wireless power transmitting terminal 10 can distribute power to a plurality of wireless power receiving apparatuses in a time division manner, but it is not limited thereto. In another example, the wireless power transmitting terminal 10 can distribute power to a plurality of wireless power receiving apparatuses using different frequency bands allocated to the wireless power receiving apparatuses.

At this time, the number of wireless power receiving apparatuses connectable to one wireless power transmitting apparatus 10 is set to at least one of the required power amount for each wireless power receiving apparatus, the battery charging state, the power consumption amount of the electronic apparatus, Can be determined adaptively based on

As another example, as shown in 200b, the wireless power transmitting terminal 10 may be composed of a plurality of wireless power transmitting apparatuses. In this case, the wireless power receiving terminal 20 may be connected to a plurality of wireless power transmission apparatuses at the same time, and may simultaneously receive power from connected wireless power transmission apparatuses to perform charging. At this time, the number of wireless power transmission apparatuses connected to the wireless power receiving terminal 20 is adaptively set based on the required power amount of the wireless power receiving terminal 20, the battery charging status, the power consumption amount of the electronic apparatus, Can be determined.

3 is a diagram for explaining a sensing signal transmission procedure in a wireless charging system according to an embodiment of the present invention.

As an example, the wireless power transmitter may be equipped with three transmit coils 111, 112, 113. Each transmit coil may overlap a portion of the transmit coil with a different transmit coil, and the wireless power transmitter may include a predetermined sense signal 117, 127 for sensing the presence of the wireless power receiver through each transmit coil - And sequentially transmits digital ping signals in a predefined order.

As shown in FIG. 3, the wireless power transmitter sequentially transmits the detection signal 117 through the primary sensing signal transmission procedure shown in reference numeral 110, and receives a signal strength indicator (Signal Strength Indicator 116 may identify the received transmit coil 111, 112. Subsequently, the wireless power transmitter sequentially transmits the detection signal 127 through the secondary detection signal transmission procedure shown in the reference numeral 120, and the signal strength indicator 126 is transmitted to the transmission coils 111 and 112 It is possible to control the efficiency (or charging efficiency) - that is, the state of alignment between the transmitting coil and the receiving coil - to identify a good transmitting coil and to allow power to be delivered through the identified transmitting coil, .

As shown in FIG. 3, the reason why the wireless power transmitter performs the two detection signal transmission procedures is to more accurately identify to which transmission coil the reception coil of the wireless power receiver is well aligned.

If the signal strength indicators 116 and 126 are received at the first transmission coil 111 and the second transmission coil 112 as shown in the aforementioned numerals 110 and 120 of FIG. 3, Selects a transmission coil having the best alignment based on the received signal strength indicator 126 in each of the first transmission coil 111 and the second transmission coil 112 and performs wireless charging using the selected transmission coil .

4 is a state transition diagram for explaining the wireless power transmission procedure defined in the WPC standard.

Referring to FIG. 4, power transmission from a transmitter to a receiver according to the WPC standard is largely divided into a selection phase 410, a ping phase 420, an identification and configuration phase 430, And a power transfer phase (step 440).

The selection step 410 may be a phase transition when a specific error or a specific event is detected while initiating a power transmission or maintaining a power transmission. Here, the specific error and the specific event will become clear through the following description. Also, in a selection step 410, the transmitter may monitor whether an object is present on the interface surface. If the transmitter detects that an object is placed on the interface surface, it can transition to the step 420 (S401). In the selection step 410, the transmitter transmits an analog ping signal of a very short pulse and can detect whether an object exists in the active area of the interface surface based on the current change of the transmission coil.

In step 420, the transmitter activates the receiver when an object is sensed, and transmits a digital ping to identify whether the receiver is a WPC compliant receiver. If the transmitter does not receive a response signal for the digital ping (e.g., a signal strength indicator) from the receiver in step 420, then the transmitter may transition back to the selection step 410 (S402). Also, in step 420, the transmitter may transition to a selection step 410 when receiving a signal indicating completion of power transmission from the receiver, i.e., a charging completion signal (S403).

Once the ping stage 420 is complete, the transmitter may transition to an identification and configuration step 430 to collect receiver identification and receiver configuration and status information (S404).

In the identifying and configuring step 430, the sender may determine whether the packet is unexpected, whether a desired packet is received during a predefined period of time (time out), a packet transmission error (transmission error) (No power transfer contract), the process can be shifted to the selection step 410 (S405).

Once the identification and configuration for the receiver is complete, the transmitter may transition to power transfer step 240, which transmits the wireless power (S406).

In the power transfer step 440, the transmitter determines whether an unexpected packet is received, a desired packet is received for a predefined period of time (time out), a violation of a predetermined power transmission contract occurs transfer contract violation, and if the charging is completed, the selection step 410 can be performed (S407).

In addition, in the power transfer step 440, if the transmitter needs to reconfigure the power transfer contract according to changes in the transmitter state, etc., it may transition to the identification and configuration step 430 (S408).

The power transmission contract may be set based on the status and characteristic information of the transmitter and the receiver. For example, the transmitter status information may include information on the maximum amount of transmittable power, information on the maximum number of receivable receivers, and the receiver status information may include information on the requested power and the like.

5 is a state transition diagram for explaining a wireless power transmission procedure defined in the WPC (Qi) standard.

Referring to FIG. 5, power transmission from a transmitter to a receiver according to the WPC (Qi) standard is largely divided into a selection phase 510, a ping phase 520, an identification and configuration phase, 530, a negotiation phase 540, a calibration phase 550, a power transfer phase 560 and a renegotiation phase 560.

The selection step 510 may be a transition step, for example, S502, S504, S506, S509, S, when a specific error or a specific event is detected while initiating a power transmission or maintaining a power transmission. Here, the specific error and the specific event will become clear through the following description. Also, in a selection step 510, the transmitter can monitor whether an object is present on the interface surface. If the transmitter detects that an object has been placed on the interface surface, it may transition to a ping step 520. In the selection step 510, the transmitter transmits an analog ping signal of a very short pulse and, based on the current change of the transmission coil or the primary coil, It is possible to detect whether or not there is an error.

At step 520, the transmitter activates the receiver when an object is detected, and transmits a digital ping to identify whether the receiver is a WPC compliant receiver. If the transmitter does not receive a response signal to the digital ping (e. G., A signal strength packet) from the receiver in step 520, then the receiver may transition back to step 510 again. Also, in the step of the ping 520, the transmitter may transition to the selection step 510 upon receiving a signal indicating that the power transmission has been completed from the receiver, that is, the charge completion packet.

Once the ping step 520 is complete, the transmitter may transition to an identification and configuration step 530 for identifying the receiver and collecting receiver configuration and status information.

In the identifying and configuring step 530, the transmitter determines whether a packet is received (unexpected packet), a desired packet is not received during a predefined period of time (time out), a packet transmission error, (No power transfer contract) can be made to the selection step 510.

The transmitter may determine whether an entry to the negotiation step 540 is required based on the negotiation field value of the configuration packet that was made in the identification and configuration step 530. [

If it is determined that negotiation is required, the transmitter may enter negotiation step 540 and perform a predetermined FOD detection procedure.

On the other hand, if it is determined that negotiation is not required, the transmitter may immediately enter the power transmission step 560.

At negotiation step 540, the transmitter may receive a Foreign Object Detection (FOD) status packet including a reference quality factor value. At this time, the transmitter can determine a threshold for FO detection based on the reference quality factor value.

Various methods by which a transmitter determines a threshold for FO detection based on a reference quality factor value will be described in detail with reference to the drawings described later.

The transmitter can use the determined threshold and the currently measured quality factor value to detect whether the FO is present in the charging area and to control the power transmission to the FO detection result.

In one example, if an FO is detected, the transmitter may return to the selection step 510. If, on the other hand, no FO is detected, the transmitter may enter power transfer step 560 via calibration step 550. In detail, if the FO is not detected, the transmitter determines the strength of the power received at the receiving end and the power loss at the receiving end and the transmitting end to determine the strength of the power transmitted at the transmitting end in the correction step 550 Can be measured. That is, the transmitter can predict the power loss based on the difference between the transmitting power of the transmitting end and the receiving power of the receiving end in the correcting step 550. A transmitter according to one embodiment may compensate the threshold for FOD detection by reflecting the predicted power loss.

In the power transfer step 540, the transmitter determines whether an undesired packet is received (unexpected packet), a desired packet is received during a predefined period of time (time out), a violation of a predetermined power transmission contract occurs transfer contract violation, and if the charging is completed, the selection step 510 can be performed.

Also, in the power transfer step 440, the transmitter may transition to the renegotiation step 570 if it is necessary to reconfigure the power transfer contract according to the transmitter state change or the like. At this time, if the renegotiation is normally completed, the transmitter may return to power transfer step 560. [

The power transmission contract may be set based on the status and characteristic information of the transmitter and the receiver. For example, the transmitter status information may include information on the maximum amount of transmittable power, information on the maximum number of receivable receivers, and the receiver status information may include information on the requested power and the like.

6 is a block diagram illustrating a structure of a wireless power transmitter according to an embodiment of the present invention.

6, the wireless power transmitter 600 may include a power conversion unit 610, a power transmission unit 620, a communication unit 630, a control unit 640, and a sensing unit 650 . It should be noted that the configuration of the wireless power transmitter 600 described above is not necessarily an essential configuration, and may be configured to include more or less components.

As shown in FIG. 6, when power is supplied from the power supply unit 660, the power conversion unit 610 may convert the power to a predetermined intensity.

For this, the power conversion unit 610 may include a DC / DC conversion unit 611 and an amplifier 612.

The DC / DC converting unit 611 may convert DC power supplied from the power supply unit 650 into DC power having a specific intensity according to a control signal of the controller 640. [

At this time, the sensing unit 650 may measure the voltage / current of the DC-converted power and provide the measured voltage / current to the controller 640. In addition, the sensing unit 650 may measure the internal temperature of the wireless power transmitter 600 and may provide the measurement result to the controller 640 in order to determine whether overheating occurs. For example, the control unit 640 may adaptively cut off the power supply from the power supply unit 650 or block the supply of power to the amplifier 612 based on the voltage / current value measured by the sensing unit 650 . To this end, a power cutoff circuit may be further provided at one side of the power conversion unit 610 to cut off power supplied from the power supply unit 650 or to cut off power supplied to the amplifier 612.

The amplifier 612 can adjust the intensity of the DC / DC-converted power according to the control signal of the controller 640. For example, the control unit 640 may receive the power reception status information and / or the power control signal of the wireless power receiver through the communication unit 630 and may receive the power control information based on the received power reception status information and / So that the amplification factor of the amplifier 612 can be dynamically adjusted. For example, the power reception status information may include, but is not limited to, the intensity information of the rectifier output voltage, the intensity information of the current applied to the reception coil, and the like. The power control signal may include a signal for requesting power increase, a signal for requesting power reduction, and the like.

The power transmitting unit 620 may be configured to include a multiplexer 621 (or a multiplexer), a transmitting coil 622, and the like. In addition, the power transmitting unit 620 may further include a carrier generator (not shown) for generating a specific operating frequency for power transmission.

The carrier generator may generate a specific frequency for converting the output DC power of the amplifier 612 delivered via the multiplexer 621 to AC power having a specific frequency. In the above description, the AC signal generated by the carrier generator is mixed with the output of the multiplexer 621 to generate AC power. However, this is only an example, It should be noted that they may be mixed only or later.

It should be noted that the frequencies of the AC power delivered to each transmit coil in accordance with an embodiment of the present invention may be different from each other. In another embodiment of the present invention, the resonance frequency of each transmission coil may be set differently by using a predetermined frequency controller having a function of controlling LC resonance characteristics for different transmission coils.

6, the power transmission unit 620 includes a multiplexer 621 and a plurality of transmission coils 622 for controlling the output power of the amplifier 612 to be transmitted to the transmission coil, that is, Th to n < th > transmit coils.

The controller 640 according to an exemplary embodiment of the present invention may transmit power through time division multiplexing for each transmission coil when a plurality of wireless power receivers are connected. For example, if the wireless power transmitter 600 has three wireless power receivers-i. E., The first through third wireless power receivers, respectively, identified through three different transmit coils, i. E., First through third transmit coils , The control unit 640 controls the multiplexer 621 to control power to be transmitted to a specific transmission coil in a specific time slot. At this time, the amount of power transmitted to the corresponding wireless power receiver may be controlled according to the length of the time slot allocated for each transmission coil, but this is only one embodiment. The power of the amplifier 612 may be controlled to control the transmission power of each wireless power receiver.

The controller 640 may control the multiplexer 621 so that the detection signals can be sequentially transmitted through the first to n'th transmission coils 622 during the first detection signal transmission procedure. At this time, the control unit 640 can identify the time at which the detection signal is transmitted using the timer 655. When the time of the transmission of the trashed signal arrives, the control unit 640 controls the multiplexer 621 to output a detection signal It can be controlled to be transmitted. For example, the timer 650 can send a specific event signal to the control unit 640 at predetermined intervals during the ping transmission step. When the event signal is detected, the control unit 640 controls the multiplexer 621 to transmit the corresponding event signal It is possible to control the digital ping to be transmitted through the coil.

In addition, the control unit 640 may transmit a predetermined transmission coil identifier for identifying a signal strength indicator (Signal Strength Indicator) through a transmission coil from the demodulation unit 632 during the first detection signal transmission procedure, Lt; / RTI > received signal strength indicator. In the second sensing signal sending process, the controller 640 controls the multiplexer 621 so that the sensing signal can be transmitted only through the transmitting coil (s) on which the signal strength indicator is received during the first sensing signal sending procedure You may. In another example, when there are a plurality of transmit coils in which the signal strength indicator is received during the first differential sense signal transmission procedure, the control unit 640 transmits the received transmit coil with the signal strength indicator having the largest value as the second differential sense signal In the procedure, the detection signal may be determined as a transmission coil to be transmitted first, and the multiplexer 621 may be controlled according to the determination result.

The modulator 631 may modulate the control signal generated by the controller 640 and transmit the modulated control signal to the multiplexer 621. Here, the modulation scheme for modulating the control signal includes a frequency shift keying (FSK) modulation scheme, a Manchester coding modulation scheme, a phase shift keying (PSK) modulation scheme, a pulse width modulation scheme, A differential bi-phase modulation method, and the like.

The demodulator 632 can demodulate the detected signal and transmit the demodulated signal to the controller 640 when a signal received through the transmission coil is detected. Here, the demodulated signal may include a signal strength indicator, an error correction (EC) indicator for power control during wireless power transmission, an end of charge indicator (EOC), an overvoltage / overcurrent / overheat indicator, But is not limited to, various status information for identifying the status of the wireless power receiver.

Also, the demodulator 632 can identify which of the transmit coils the demodulated signal is received, and provide the control unit 640 with a predetermined transmit coil identifier corresponding to the identified transmit coil.

 The demodulation unit 632 can demodulate the signal received through the transmission coil 623 and transmit the demodulated signal to the control unit 640. In one example, the demodulated signal may include, but is not limited to, a signal strength indicator, and the demodulated signal may include various status information of the wireless power receiver.

In one example, the wireless power transmitter 600 may obtain the signal strength indicator through in-band communication that uses the same frequency used for wireless power transmission to communicate with the wireless power receiver.

In addition, the wireless power transmitter 600 can transmit wireless power using the transmit coil 622, as well as exchange various information with the wireless power receiver via the transmit coil 622. As another example, the wireless power transmitter 600 may further include a separate coil corresponding to each of the transmission coils 622 (i.e., the first to n < th > transmission coils) It should be noted that it may also perform in-band communication with the receiver.

Although the wireless power transmitter 600 and the wireless power receiver perform in-band communication in the description of FIG. 6, this is merely an example, and the frequency band used for the wireless power signal transmission Directional communication through different frequency bands. For example, the near-end bi-directional communication may be any one of low-power Bluetooth communication, RFID communication, UWB communication, and Zigbee communication.

In particular, the wireless power transmitter 600 according to an embodiment of the present invention may adaptively provide a fast charge mode and a general low power charge mode at the request of the wireless power receiver.

The wireless power transmitter 600 can transmit a signal of a predetermined pattern, which is called a first packet for convenience of explanation, when the fast charge mode is supported. The wireless power receiver 600 may identify that the wireless power transmitter 600 being connected is capable of fast charge when the first packet is received.

In particular, the wireless power receiver may send a first response packet to the wireless power transmitter 6000 requesting fast charging if fast charging is required.

In particular, the wireless power transmitter 600 may automatically switch to the fast charge mode and initiate fast charge when a predetermined time has elapsed after the first response packet is received.

For example, when the control unit 640 of the wireless power transmitter 600 transits to the power transmission step 440 or 540 of FIGS. 4 through 5, the control unit 640 controls the first packet to be transmitted through the transmission coil 622 However, this is only one example, and another example of the present invention may be the first packet sent out in the identification and configuration step 430 of FIG. 4 or the identifying step 530 of FIG.

It should be noted that another embodiment of the present invention may transmit encoded information that can identify whether or not fast charge support is possible to the digital ring signal transmitted by the wireless power transmitter 600. [

The wireless power receiver may send a predetermined charge mode packet to the wireless power transmitter 600 where the charge mode is set to fast charge if a fast charge is needed at any point in the power transfer phase. 8 through 12. Of course, the wireless power transmitter 600 and the wireless power receiver may be configured such that, when the charging mode is changed to the fast charging mode, Lt; RTI ID = 0.0 > transmit / receive < / RTI > For example, when the charging mode is changed from the normal low-power charging mode to the fast-charging mode, the overvoltage determination criterion, the over temperature criterion, the low-voltage / high- Level (Optimum Voltage Level), power control offset, and the like can be changed and set.

For example, when the charging mode is changed from the normal low-power charging mode to the fast-charging mode, the threshold voltage for determining the overvoltage may be set to be high enough to enable fast charging. As another example, the critical temperature for determining whether overheating occurs may be set high considering the temperature rise due to fast charging. As another example, the power control offset value, which means the minimum level at which the power at the transmitting end is controlled, may be set to a larger value as compared with the general low power charging mode so as to be able to quickly converge to a desired target power level in the fast charging mode.

7 is a block diagram illustrating a structure of a wireless power receiver interworking with the wireless power transmitter according to the FIG.

7, the wireless power receiver 700 includes a receiving coil 710, a rectifier 720, a DC / DC converter 730, a load 740, a sensing unit 750, 760, and a main control unit 770. Here, the communication unit 760 may include a demodulation unit 761 and a modulation unit 762.

Although the wireless power receiver 700 shown in the example of FIG. 7 is shown as being capable of exchanging information with the wireless power transmitter 600 through in-band communication, this is only one embodiment, The communication unit 760 according to another embodiment of the present invention may provide short-distance bidirectional communication through a frequency band different from the frequency band used for wireless power signal transmission.

The AC power received via the receiving coil 710 may be delivered to the rectifier 720. The rectifier 720 may convert the AC power to DC power and transmit it to the DC / DC converter 730. [ The DC / DC converter 730 may convert the intensity of the rectifier output DC power to a specific intensity required by the load 740 and then forward it to the load 740.

The sensing unit 750 may measure the intensity of the DC power output from the rectifier 720 and provide it to the main control unit 770. Also, the sensing unit 750 may measure the intensity of the current applied to the reception coil 710 according to the wireless power reception, and may transmit the measurement result to the main control unit 770. The sensing unit 750 may measure the internal temperature of the wireless power receiver 700 and provide the measured temperature value to the main control unit 770.

For example, the main control unit 770 may compare the measured rectifier output DC power with a predetermined reference value to determine whether an overvoltage is generated. As a result of the determination, if an overvoltage is generated, a predetermined packet indicating that the overvoltage has occurred can be generated and transmitted to the modulating unit 762. Here, the signal modulated by the modulating unit 762 may be transmitted to the wireless power transmitter 600 through the receiving coil 710 or a separate coil (not shown). The main control unit 770 may determine that the detection signal is received when the intensity of the rectifier output DC power is equal to or greater than a predetermined reference value and when the signal strength indicator corresponding to the detection signal is received by the modulation unit 762 The demodulator 761 may control the AC power signal between the receiving coil 710 and the rectifier 720 or the AC power signal between the rectifier 720 and the rectifier 720, DC power signal to identify whether or not the detection signal has been received, and provide the result of the identification to the main control unit 770. [ At this time, the main control unit 770 may control the signal intensity indicator corresponding to the detection signal to be transmitted through the modulation unit 761. [

In particular, the main control unit 770 according to the embodiment of the present invention may determine whether the connected wireless power transmitter is a wireless power transmitter capable of fast charging based on the information demodulated by the demodulation unit 760. [

Also, the main control unit 770 generates a charge mode packet corresponding to the received fast charge request signal when a predetermined fast charge request signal for requesting fast charge is received from the electronic device 30 of FIG. 1, (761). Here, the fast charge request signal from the electronic device can be received according to the user menu selection on the predetermined user interface.

The main control unit 770 according to another embodiment of the present invention automatically requests the wireless power transmitter to perform fast charging based on the battery remaining amount or wireless power It is also possible to control the transmitter to stop fast charging and switch to a normal low-power charging mode.

The main control unit 770 according to another embodiment may monitor the power consumption of the electric device during charging to the general low-power charging mode in real time. If the power consumption of the electronic device is equal to or greater than a predetermined reference value, the main control unit 770 may generate a predetermined charging mode packet requesting switching to the fast charging mode and transmit the generated charging mode packet to the modulation unit 761. [

The main control unit 770 according to another embodiment of the present invention can determine whether overheating occurs by comparing the internal temperature value measured by the sensing unit 750 with a predetermined reference value. If overheating occurs during the fast charging, the main control unit 770 may generate and transmit a charging mode packet so that the wireless power transmitter is switched to a general low power charging mode.

The main control unit 770 according to another embodiment of the present invention changes the charging mode based on at least one of the battery charging rate, the internal temperature, the intensity of the rectifier output voltage, the CPU usage rate mounted on the electronic apparatus, And if it is determined that the charging mode should be changed, the charging mode packet including the charging mode value to be changed may be generated and transmitted to the wireless power transmitter.

8 is a diagram for explaining a modulation and demodulation method of a wireless power signal according to an embodiment of the present invention.

As shown in FIG. 8, the wireless power transmitter 10 and the wireless power receiver 20 can encode or decode a packet to be transmitted based on an internal clock having the same period.

Hereinafter, a method of encoding a packet to be transmitted will be described in detail with reference to FIGS. 1 to 8. FIG.

Referring to FIG. 1, when the wireless power transmitter 10 or the wireless power receiver 20 does not transmit a specific packet, the wireless power signal is modulated with modulation having a specific frequency, May be an alternating current signal. On the other hand, when the wireless power transmitting terminal 10 or the wireless power receiving terminal 20 transmits a specific packet, the wireless power signal may be an alternating signal modulated by a specific modulation method, as shown in FIG. For example, the modulation scheme may include, but is not limited to, an amplitude modulation scheme, a frequency modulation scheme, a frequency and amplitude modulation scheme, a phase modulation scheme, and the like.

The binary data of the packet generated by the wireless power transmitting terminal 10 or the wireless power receiving terminal 20 may be subjected to differential bi-phase encoding as shown in 820. [ Specifically, the differential two-stage encoding has two state transitions to encode data bit one and one state transition to encode data bit zero. That is, the data bit 1 is encoded such that the transition between the HI state and the LO state occurs at the rising edge and the falling edge of the clock signal, and the data bit 0 is at the rising edge of HI State and the LO state may be encoded to occur.

The encoded binary data may be subjected to a byte encoding scheme, as shown in FIG. Referring to reference numeral 830, a byte encoding method according to an embodiment of the present invention includes a start bit and a stop bit for identifying a start and a type of a bitstream of an 8-bit encoded binary bitstream, , And a parity bit for detecting whether or not an error has occurred in the bitstream (byte).

9 is a diagram for explaining a packet format according to an embodiment of the present invention.

9, a packet format 900 used for information exchange between the wireless power transmitting terminal 10 and the wireless power receiving terminal 20 includes a function of acquiring synchronization for demodulating the packet and identifying an accurate start bit of the packet A header 920 for identifying a type of a message included in the packet, a message for transmitting the content of the packet (or a payload), a preamble field 910 for transmitting the packet, 930) field and a checksum (940) field for identifying whether an error has occurred in the packet.

As shown in FIG. 9, the packet receiving end may identify the size of the message 930 included in the packet based on the header 920 value.

In addition, the header 920 may be defined for each step of the wireless power transmission procedure, and some values of the header 920 may be defined at different levels. For example, referring to FIG. 9, it should be noted that the header value corresponding to the end power transfer in the ping phase and the power transmission phase in the power transfer phase may be equal to 0x02.

The message 930 includes data to be transmitted at the transmitting end of the packet. For example, the data contained in the message 930 field may be, but is not limited to, a report, request or response to the other party.

The packet 900 according to another embodiment of the present invention may further include at least one of a transmitting end identification information for identifying a transmitting end that transmitted the packet and a receiving end identifying information for identifying a receiving end to receive the packet. Here, the transmitter identification information and the receiver identification information may include IP address information, MAC address information, product identification information, and the like. However, the present invention is not limited thereto.

The packet 900 according to another embodiment of the present invention may further include predetermined group identification information for identifying a corresponding receiving group when the packet is to be received by a plurality of apparatuses.

10 is a view for explaining the types of packets transmitted from a wireless power receiver to a wireless power transmitter according to an embodiment of the present invention.

Referring to FIG. 10, a packet transmitted from a wireless power receiver to a wireless power transmitter includes a signal strength packet for transmitting strength information of a detected ping signal, a power transmission type for requesting a transmitter to stop power transmission, A power control hold-off packet for transmitting time information for waiting until the actual power is adjusted after receiving the control error packet for control control, a configuration for transmitting the configuration information of the receiver, Packet, an identification packet for transmitting the receiver identification information and an extension identification packet, a general request packet for transmitting a general request message, a special request packet for transmitting a special request message, a reference quality parameter value for detecting FO, A FOD state packet, a control error packet for controlling the transmission power of the transmitter, a renegotiation packet for starting renegotiation, A 24-bit receive power packet and an 8-bit receive power packet for transmitting received power intensity information and a charge status packet for transmitting charge status information of the current load.

The packets transmitted from the wireless power receiver to the wireless power transmitter may be transmitted using in-band communication using the same frequency band as that used for wireless power transmission.

11 is a block diagram for explaining a structure of a foreign substance detecting apparatus according to an embodiment of the present invention.

11, the foreign substance detecting apparatus 1100 includes a power supply unit 1101, a DC-DC converter 1102, an inverter 1103, a resonant capacitor 1104, a transmission coil 1105, A quality factor measurement unit 1106, a demodulation unit 1107, a modulation unit 1108, a sensing unit 1109, and a control unit 1907.

The power supply unit 1101 receives the DC power through the external power terminal and transmits the DC power to the DC-DC converter 1102.

DC-DC converter 1102 can convert the intensity of the DC power received from the power supply unit 1101 into the DC power of a specific intensity under the control of the controller 1110. For example, the DC-DC converter 1102 may be configured as a variable voltage generator capable of adjusting the intensity of a voltage, but is not limited thereto.

The inverter 1103 can convert the converted DC power into AC power. The inverter 1103 can convert a DC signal inputted through a plurality of switch controls into an AC signal and output it.

For example, the inverter 1103 may include a full bridge circuit, but the present invention is not limited thereto and may include a half bridge.

In other words, the inverter 1103 may be configured to include both a half bridge circuit and a full bridge circuit. In this case, the controller 1110 may determine whether the inverter 1103 is operated as a half bridge or a full bridge . The wireless power transmission apparatus according to an exemplary embodiment of the present invention may adaptively control the bridge mode of the inverter 1103 according to the intensity of power required by the wireless power receiving apparatus. For example, when the wireless power receiving apparatus requires a low power of 5W, the control unit 1110 can control the half bridge circuit of the inverter 1103 to be driven. On the other hand, when the wireless power receiving apparatus requires a high power of 15 W, the control unit 1110 can control the full bridge circuit to be driven. In another example, the wireless power transmission device may selectively drive a full bridge circuit or a half bridge circuit adaptively according to the sensed temperature. For example, when the temperature of the wireless power transmission apparatus during the wireless power transmission using the half bridge circuit exceeds a predetermined reference value, the controller 1110 may disable the half bridge circuit and activate the full bridge circuit. That is, the wireless power transmission apparatus can lower the temperature of the wireless power transmission apparatus to below the reference value by raising the voltage through the full bridge circuit and reducing the intensity of the current flowing through the transmission coil 1105 for power transmission of the same intensity have. Generally, the amount of heat generated in the electronic component mounted on the electronic device may be more sensitive to the intensity of the current than the voltage applied to the electronic component.

In addition, the inverter 1103 can change the intensity of the AC power as well as convert the DC power to the AC power.

For example, the inverter 1103 may control the intensity of the alternating-current power output by controlling the frequency of the reference alternating current signal used for generating the alternating-current power under the control of the controller 1110. For this purpose, the inverter 1103 may comprise a frequency oscillator that generates a reference AC signal having a specific frequency, but this is only one embodiment, and another example is that the frequency oscillator is separate from the inverter 1103 As shown in FIG.

The quality factor measurement unit 1106 may monitor a change in inductance (or voltage or current) at both ends of the resonant capacitor 1104 and measure a quality factor value for a transmission coil of the corresponding wireless power transmission apparatus. At this time, the measured current quality factor value is transmitted to the controller 1110.

For example, the controller 1110 may measure quality factor values in the selection steps 410 and 510 of FIGS. The control unit 1110 determines whether or not a foreign object is detected based on a measured quality factor value (Measured_Quality_Factor_Value, MQF_Value) and a reference quality factor value (RQF_Value) Detection Quality Factor Threshold Value, FOD_QFT_Value) to determine whether a foreign substance is present.

Here, RQF_Value may be determined as a value having the smallest value among the quality factor values measured at a plurality of points on the charging area of a specific wireless power transmitter designated for performance test.

The FOD_QFT_Value can be determined from the RQF_Value by subtracting the reference quality factor accuracy from the production and measurement error.

Here, the reference quality factor accuracy may be an allowable range of error with respect to the reference quality factor value measured when no foreign matter exists. For example, the reference quality factor value to which the tolerance of the error is applied may be set to a ratio of increasing or decreasing with respect to the reference quality factor value received from the wireless power receiving apparatus, but is not limited thereto.

The current WPC Qi standard defines the same reference quality factor accuracy for all products.

However, the reference quality factor accuracy may be different depending on the manufacturer of the product and the type of product. For example, the A and B radio power receivers can measure the reference quality factor value in conjunction with the same radio power transmitter. However, the accuracy of the measured reference quality factor values for the two products may differ. Thus, the wireless power transmitter can obtain information about the reference quality factor accuracy for each wireless power receiver and determine the FOD_QFT_Value for determining the presence of a foreign object based on the obtained reference quality factor accuracy.

For example, as a result of testing for the same wireless power transmitter, the reference quality factor value measured for A's wireless power receiver is 100, and the reference quality factor value measured for B's wireless power receiver may be 70. In this case, the reference quality factor accuracy - e.g. +/- 7% - corresponding to the company B wireless power receiver corresponds to the reference quality factor accuracy - +/- 10% - < / RTI > That is, the sensitivity to the error can be set higher for the wireless power receiver of the company B than the company A.

In this manner, the reference quality factor accuracy can be applied differently according to the configuration of the electronic apparatus equipped with the wireless power receiving apparatus, for example, a smart phone. For example, if the mounting type and the mounting type of the PCB, the camera module, the antenna and other parts mounted on the smart phone are different, the error range of the reference quality factor value measurement may be different.

The demodulator 1107 demodulates the inband signal received from the wireless power receiver and transmits the demodulated signal to the controller 1110. For example, the demodulator 1107 can demodulate the FOD state packet of FIG. 12 to be described later and transmit the demodulated FOD state packet to the controller 1110. Here, the FOD status packet may be received from the wireless power receiving apparatus in negotiation step 540 of FIG. 5 above.

The modulator 1108 modulates the control packet received from the controller 1110 and transmits the modulated control packet through the transmission coil 1105. For example, when the FOD status packet is received, the control unit 1110 determines whether a foreign matter determination based on the quality factor value is possible, and transmits an ACK packet or a NACK packet to the wireless power receiving unit 1108 through the modulation unit 1108 Device.

Here, the ACK packet may mean that the wireless power transmission apparatus performs a foreign matter detection procedure based on the quality factor value. On the other hand, the NACK packet may mean that the foreign substance detection procedure based on the quality factor value is not performed. The wireless power transmission device can identify whether or not it is possible to detect foreign matter based on the quality factor value based on the installed software version and the installed hardware version.

The sensing unit 1109 can measure voltage, current, power, temperature, and the like at a specific node, a specific part, and a specific position of the wireless power transmission apparatus. For example, the sensing unit 1109 may measure the current / voltage / power between the DC-DC converter 1102 and the inverter 1103, and may transmit the measurement result to the controller 1110. In another example, the sensing unit 1109 may measure the intensity of the current flowing through the transmission coil 1105 and the intensity of the voltage applied across the transmission coil 1105, and may transmit the measurement result to the control unit 1110.

The controller 1110 according to an embodiment of the present invention can determine the presence of a foreign substance by comparing the intensity I_rail of the current applied to the inverter 1103 with a predetermined current threshold. As a result of the determination, if there is a high probability that a foreign matter exists, the controller 1110 can adjust the reference quality factor accuracy to a certain low level. For example, if it is determined that the possibility of the presence of foreign matter is high, the controller 1110 may determine the FOD_QFT_Value by adjusting the reference quality factor accuracy from +/- 10% to +/- 5%. Accordingly, the control unit 1110 can improve the accuracy of foreign matter detection when determining whether or not a foreign substance exists based on the quality factor value. On the other hand, if it is determined that the possibility of foreign matter is low as a result of the determination, the controller 1110 can determine the FOD_QFT_Value based on the predefined reference quality factor accuracy.

If the MQF_Value is smaller than the FOD_QFT_Value, the controller 1110 can determine that foreign matter exists. If there is a foreign object, the control unit 1110 may not enter the power transmission step 560 in the negotiation step 540 of FIG. At this time, the control unit 1110 can control the predetermined notification unit included in the wireless power transmission apparatus so that the user recognizes that the foreign substance exists in the charging area. Here, the notifying means may include, but is not limited to, a beeper, an LED lamp, a vibrating element, a liquid crystal display, or the like.

 If the MQF_Value is equal to or greater than FOD_QFT_Value, the controller 1110 can determine that no foreign matter exists in the charging area. If there is no foreign object, the controller 1110 enters the power transmission step and controls the power required by the corresponding wireless power transmission apparatus to be transmitted.

In addition, the controller 1110 according to another embodiment of the present invention may control the current value measured in the ping step, for example, the output current I_rail of the DC-DC converter or the current I_coil applied to the transmission coil 1105 ) May be compared with a predetermined reference current value. As a result of comparison, if the measured current value is larger than the reference current value, it can be judged that the possibility of foreign matter is low. In this case, even if the FOD status packet is received in the negotiation step, the controller 1110 may enter the power transmission step without proceeding with the foreign matter determination process based on the quality factor value.

11, the inverter input current I_rail is DC power, and the current flowing in the transmission coil 1105 is AC current. In particular, the current input to the inverter 1103 in the ping stage is DC power having a constant level, and the output power of the inverter 1103 is AC power that is discontinuously transmitted in a constant cycle. Therefore, the time average value of I_rail can be relatively large compared to the time average value of I_coil. Therefore, it is possible to significantly reduce the probability of misjudgment based on the I_rail measured based on the measured I_rail in the pinging step. However, the present invention is not limited to this, and based on the I_coil value measured at the ping step, It should be noted that it can be judged.

When a conductive foreign matter other than a normal wireless power receiving apparatus is located in the charging region of the wireless power transmission apparatus, the mutual impedance value between the transmission coil and the foreign matter becomes close to zero. At this time, the intensity of the current I_rail applied to the inverter 1103 rapidly increases. Accordingly, the controller 1110 can determine the possibility of foreign matter by monitoring the intensity of the current I_rail applied to the inverter 1103 in the ping stage.

As described above, the wireless power transmission apparatus according to the present invention judges the possibility of existence of a foreign object on the basis of the current change in the ping step, and performs the foreign matter detection procedure based on the quality factor value adaptively according to the determination result , Unnecessary procedures can be minimized. Further, in the wireless power transmission apparatus according to the present invention, when it is determined that the possibility of foreign matter is high, the precision of the foreign substance detection can be improved by adjusting the reference quality factor accuracy lower than the default setting value.

The foreign matter detection method defined in the present WPC Qi standard measures the present quality factor value before the wireless power transmitter performs the ping step, that is, the selection step. The wireless power transmitter uses the reference quality factor value received from the wireless power receiver during the negotiation phase and the production and measurement tolerance to take into account the design difference between the transmitter and the reference quality factor accuracy The quality factor threshold value for determining the presence or absence of a foreign substance is determined in consideration of the Accuracy of Reference Quality Factor.

In one example, the production and measurement error values may be constant values determined based on at least one of the power class of the wireless power transmitter, the characteristics of the transmit coil mounted on the wireless power transmitter, and the configuration thereof.

The reference quality factor value is determined based on five areas (middle, 5 mm left and right, and four positions shifted left and right) of the charging area of the test power transmitter (TPT: for example, the transmitter of the MP1 type defined in the WPC Qi standard) Quot; means the smallest value among the quality factor values measured in the " Depending on the design difference between the test power transmitter MP1 and the commercial wireless power transmitter - including, for example, the inductance value of the transmit coil - the quality factor value measured in the actual charging area may vary from transmitter to transmitter. The error that corrects this is called production and measurement error.

The reference quality factor value may be determined to be a value having the smallest value among the quality factor values measured at a plurality of points on the charging area of the specific wireless power transmitter designated for performance testing and maintained in the wireless power receiver.

For example, the reference quality factor (RQF_FO) is measured at a central position where the primary coil and the secondary coil are well aligned with no FO near the radio power receiver placed in the charging area For example, +/- 5 mm in the x and y axes, respectively, without a rotation of the wireless power receiver in the absence of FO in the vicinity of the first quality factor and the wireless power receiver, Not limited to - and may be determined to be the smallest of the measured second quality factor values. Here, the second quality factor values may be a quality factor value measured at at least four different locations.

The foreign substance detecting apparatus according to an embodiment of the present invention considers the reference quality factor value received through the FOD state packet, the reference quality factor accuracy determined according to the determination result of foreign matter existence in the ping stage, And a production and measurement tolerance for determining a threshold value for foreign matter detection.

12 is a diagram for explaining a message structure of an FOD state packet according to the present invention.

Referring to FIG. 12, the FOD status packet message 1200 may have a length of 2 bytes. The FOD status packet message 1200 includes a 6-bit reserved (Reserved) field 1201, a 2-bit mode field 1202, And a reference quality factor value (1203).

All the bits constituting the reserved field 1201 may be set to zero.

If the mode 1202 field is set to binary number '00', as shown in reference numeral 1204, a reference quality factor value determined by measuring the power quality of the wireless power receiver in the OFF state of the reference quality factor value 1203 May be recorded.

13 is a flowchart illustrating a foreign matter detection method in a wireless power transmission apparatus according to an embodiment of the present invention.

Referring to FIG. 13, the wireless power transmission apparatus measures a quality factor value of a transmission coil in a selection step, and stores the measured quality factor value (Measured_QF_Value) in a predetermined recording area (S1301).

When the wireless power transmission apparatus detects an object in the selection step, it can enter the ping phase and transmit the digital ping signal.

The wireless power transmission apparatus can measure the intensity of the current I_rail applied to the inverter in the step of ping (S1302).

The measured I_rail intensity is compared with a predetermined reference current value I_threshold so that the wireless power transmission apparatus can determine the presence of foreign matter (S1303).

Here, if the measured I_rail intensity is smaller than the I_threshold as a result of the comparison, the wireless power transmission apparatus can determine that the possibility of foreign matter is high. On the other hand, if the measured I_rail intensity is equal to or greater than the I_threshold as a result of the comparison, the wireless power transmission apparatus can determine that the possibility of foreign matter is low.

As a result of the determination in step 1303, if it is determined that the possibility of foreign matter is high, the wireless power transmission apparatus can correct the reference quality factor accuracy set in default (S1304). According to one embodiment, the wireless power transmission apparatus can lower the reference quality factor accuracy set by default to a certain level. For example, if the default reference quality factor accuracy is +/- 10%, the calibration reference quality factor accuracy may be +/- 5%, but is not so limited, and the calibration level may vary depending on the design of the skilled person .

On the other hand, if it is determined in step 1303 that the possibility of foreign matter is low, the reference quality factor accuracy set as default can be maintained as it is.

When the wireless power transmission apparatus enters the negotiation step, it can receive the FOD status packet including the reference quality factor value from the wireless power receiving apparatus (S1305).

The wireless power transmission apparatus may determine a foreign matter detection reference quality threshold (FOD_QFT_Value) based on the reference quality factor value received from the wireless power receiving apparatus and the current reference quality factor accuracy (S1306). Here, the foreign matter detection reference quality threshold value may be determined by further considering a production and measurement tolerance for considering a design difference between transmitters.

The wireless power transmitting apparatus can compare the previously stored Measured_QF_Value with the FOD_QFT_Value to determine whether or not a foreign substance exists in the charged area (S1307).

As a result of the comparison, if the Measured_QF_Value is equal to or greater than FOD_QFT_Value, the wireless power transmission apparatus can judge that no foreign matter exists. On the other hand, as a result of the comparison, if the Measured_QF_Value is smaller than the FOD_QFT_Value, the wireless power transmission apparatus can determine that foreign matter exists.

If it is determined in step 1307 that no foreign substance is present, the wireless power transmission apparatus may enter the power transmission step (S1308).

If it is determined in step 1307 that a foreign substance is present, the wireless power transmission apparatus outputs a predetermined notification signal or notification message indicating that the foreign substance is detected, and may enter the selection step (S1309).

FIG. 14 is a flowchart illustrating an operation of a wireless power transmission apparatus in a state where a foreign object is detected according to an embodiment of the present invention.

Referring to FIG. 14, the wireless power transmission apparatus can measure the intensity of the current I_rail applied to the inverter when the foreign substance enters the ping stage in a state where it is detected (S1401).

The wireless power transmission apparatus can compare the measured I_rail intensity with I_threshold to determine whether the detected foreign matter is removed from the charging region (S1402).

If the measured I_rail value is greater than or equal to the I_threshold, the wireless power transmission apparatus determines that the foreign substance is removed, and proceeds to step 1301 of FIG. 13 (S1404).

On the other hand, if it is determined that the measured I_rail value is smaller than I_threshold, it is determined that the detected foreign matter is still present in the charging area and the transmission of the ping signal is delayed for a predetermined time (S1403). Accordingly, the present invention is advantageous in that unnecessary power waste and heat generation due to foreign substances can be minimized when foreign substances are present.

FIG. 15 is a flowchart illustrating an FOD detection method according to an embodiment of the present invention.

The wireless power transmission apparatus can receive the FOD status packet including the reference quality factor value in the negotiation step (S1501).

The wireless power transmission apparatus can determine whether the possibility of the presence of foreign matter is high (S1502).

As a result of the determination, if there is a high possibility that a foreign object exists, the wireless power transmission apparatus may generate a NACK packet, transmit the NACK packet to the wireless power receiving apparatus, and then enter the selection step (S1503).

As a result of the determination in step 1502, if the possibility of foreign matter is low, the wireless power transmission apparatus may generate an ACK packet, transmit the generated ACK packet to the wireless power reception apparatus, and perform a foreign matter detection procedure based on the quality factor value S1505).

In the embodiment of FIG. 15, the determination of the possibility of foreign matter may be determined by comparing the current value of the current applied to the inductor of the wireless power transmission apparatus, that is, the I_rail value, and the predetermined inductor current threshold value I_rail_threshold However, the present invention is not limited to this, and another embodiment may be determined by comparing an intensity of a current flowing through a transmission coil, that is, an I_coil value, and a coil current threshold value I_coil_threshold.

The methods according to the above-described embodiments may be implemented as a program for execution in a computer and stored in a computer-readable recording medium. Examples of the computer-readable recording medium include ROM, RAM, CD- , A floppy disk, an optical data storage device, and the like, and may also be implemented in the form of a carrier wave (for example, transmission over the Internet).

The computer readable recording medium may be distributed over a networked computer system so that computer readable code can be stored and executed in a distributed manner. And, functional program, code, and code segments for implementing the above-described method can be easily inferred by programmers in the technical field to which the embodiment belongs.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof.

Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

Claims (24)

A method for detecting foreign matter in a wireless power transmitter,
Storing a quality factor value measured at the selecting step;
Determining whether the foreign substance is present in the pinging step;
If it is determined that the possibility of the foreign substance is high, correcting the reference quality factor accuracy set as a default;
Determining a quality factor threshold for foreign matter detection using the corrected reference quality factor accuracy; And
Comparing the determined quality factor threshold with the measured quality factor value to detect foreign matter
And detecting the foreign matter. The method according to claim 1,
Measuring the intensity of the output current in the ping stage; And
Comparing the intensity of the measured sending current with a predetermined current reference value to determine the possibility of the foreign matter
Further comprising the steps of: 3. The method of claim 2,
Wherein the intensity of the sending current is an intensity of a current input to an inverter included in the wireless power transmission apparatus. The method of claim 3,
Wherein the intensity of the transmission current is an intensity of a current flowing in a transmission coil provided in the wireless power transmission apparatus. The method according to claim 1,
Wherein the accuracy of the reference quality factor set to the default is corrected to be lowered to a certain level when it is determined that the possibility of the foreign substance is high. The method according to claim 1,
Further comprising the step of maintaining the reference quality factor accuracy set to the default as it is when it is determined that the possibility of the presence of the foreign substance is low. The method according to claim 1,
Further comprising receiving a Foreign Object Detection (FOD) status packet including a reference quality factor value in a negotiation step, wherein the corrected reference quality factor accuracy is applied to the reference quality factor value, And detecting the foreign matter. 8. The method of claim 7,
Wherein production and measurement error values for considering transmitter-specific design differences are further applied to the reference quality factor value to determine the quality factor threshold value. 9. The method of claim 8,
Wherein the production and measurement error values are constant values determined based on at least one of a power class of the wireless power transmitter, a characteristic and an arrangement structure of a transmission coil mounted on the wireless power transmitter. The method according to claim 1,
If no foreign object is detected, transmits an ACK packet to the corresponding wireless power receiver, and then transitions to a power transmission step. The method according to claim 1,
And if the foreign object is detected as a result of the comparison, the NACK packet is transmitted to the corresponding wireless power receiver, and then the NACK packet enters the selection step. 12. The method of claim 11,
Further comprising the step of determining whether or not the foreign substance is removed based on the intensity of the output current measured in a state where the foreign matter is detected, and if it is determined that the detected foreign matter is not removed, And delays the transmission of the foreign matter. A computer-readable recording medium on which a program for executing the method according to any one of claims 1 to 12 is recorded. In the foreign substance detecting device,
A quality factor measurement unit for measuring a quality factor value for the transmission coil in a selection step;
A sensing unit for measuring the intensity of the output current in the ping stage; And
A controller for determining a possibility of foreign matter based on the measured intensity of the sending current and correcting a reference quality factor accuracy set as a default when it is determined that the possibility of the presence of the foreign matter is high,
Wherein the control unit determines the quality factor threshold value for foreign matter detection using the corrected reference quality factor accuracy. 15. The method of claim 14,
Wherein the control unit determines that the possibility of the foreign substance is high if the measured intensity of the sending current is smaller than a predetermined current reference value. 15. The method of claim 14,
The foreign substance detecting device
A DC-DC converter for converting DC power applied from a power source into specific DC power; And
An inverter for converting the converted DC power into AC power
And the intensity of the sending current is an intensity of a current flowing between the DC-DC converter and the inverter. 15. The method of claim 14,
Wherein the foreign matter detecting device further comprises an LC resonant circuit composed of a resonant capacitor and an inductor for radiating alternating power in a wireless manner, and the intensity of the outgoing current is an intensity of a current flowing in the inductor. 15. The method of claim 14,
And the control unit controls the reference quality factor accuracy set as the default to be maintained when it is determined that the possibility of the presence of the foreign substance is low. 15. The method of claim 14,
The foreign substance detecting device
Further comprising a demodulation unit for receiving a foreign object detection (FOD) status packet including a reference quality factor value in the negotiation step, wherein the control unit applies the corrected reference quality factor accuracy to the reference quality factor value, And determines the value of the foreign matter. 20. The method of claim 19,
Wherein production and measurement error values for considering transmitter-specific design differences are further applied to the reference quality factor value to determine the quality factor threshold value. 21. The method of claim 20,
Wherein the production and measurement error values are constant values determined based on at least one of a power class of the wireless power transmitter, a characteristic and an arrangement structure of a transmission coil mounted on the wireless power transmitter. 15. The method of claim 14,
And if the foreign object is not detected as a result of the comparison, the control unit controls the transition to the power transmission step after transmitting the ACK packet. 15. The method of claim 14,
And when the foreign object is detected as a result of the comparison, the controller controls the controller to enter the selection step after transmitting the NACK packet to the corresponding wireless power receiver. 24. The method of claim 23,
The control unit determines whether the foreign substance is removed based on the measured intensity of the sending current in the state where the foreign substance is detected, and if it is determined that the foreign substance is not removed as a result of the determination, So that the foreign matter is detected.

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