WO2019027158A1 - Wireless power transmitter and controlling method for wireless power transmitter - Google Patents

Abstract

The present invention relates to a wireless power transmitter and a controlling method for the wireless power transmitter. The controlling method for a wireless power transmitter according to an embodiment of the present invention may comprise the steps of: receiving an end power transfer packet from a wireless power receiver; upon receiving the end power transfer packet, ending power transfer and measuring an end temperature at the time point when the end power transfer packet has been received; calculating the temperature difference between the end temperature and a temperature measured again at the time point when a first period of time has elapsed; and when the temperature difference satisfies a transfer resumption condition, resuming power transfer to the wireless power receiver.

Description

Control method of wireless power transmitter and wireless power transmitter

The present invention relates to a wireless power transmitter.

2. Description of the Related Art [0002] Generally, as an example of an electrical connection between a charging device and a battery for charging electric power of a battery, a commercial electric power is supplied to a terminal for converting electric power into voltage and current corresponding to the battery, Supply method. This type of terminal supply is accompanied by the use of physical cables or wires. Therefore, when handling a lot of terminal-supplied equipment, many cables occupy considerable work space, are difficult to organize, and are not well apparent. Also, the terminal supply method may cause problems such as instantaneous discharge due to different potential difference between terminals, burnout due to foreign substances, fire, natural discharge, battery life and deterioration of performance.

In order to solve such a problem, a charging system (hereinafter referred to as a "wireless charging system") and a control method using a method of transmitting power wirelessly are proposed. In addition, since the wireless charging system has not been installed in some terminals in the past and the consumer has to purchase a separate wireless charging receiver accessory, the demand for the wireless charging system is low, but the wireless charging user is expected to increase rapidly. It is expected to be equipped with charging function.

Generally, a wireless charging system comprises a wireless power transmitter for supplying electric energy in a wireless power transmission mode and a wireless power receiver for receiving electric energy supplied from a wireless power transmitter to charge the battery.

Such a wireless charging system may transmit power by at least one wireless power transmission scheme (e.g., electromagnetic induction scheme, electromagnetic resonance scheme, RF wireless power transmission scheme, etc.).

For example, the wireless power transmission scheme may use various wireless power transmission standards based on an electromagnetic induction scheme in which a magnetic field is generated in a power transmission terminal coil and charged using an electromagnetic induction principle in which electricity is induced in a reception terminal coil due to the magnetic field . Here, the electromagnetic induction type wireless power transmission standard may include an electromagnetic induction wireless charging technique defined in a Wireless Power Consortium (WPC) or a Power Matters Alliance (PMA).

In another example, the wireless power transmission scheme may employ an electromagnetic resonance scheme in which the magnetic field generated by the transmission coil of the wireless power transmitter is tuned to a specific resonance frequency to transmit power to a nearby wireless power receiver . Here, the electromagnetic resonance method may include a resonance-type wireless charging technique defined in the Alliance for Wireless Power (A4WP) standard mechanism, a wireless charging technology standard mechanism.

In another example, a wireless power transmission scheme may use an RF wireless power transmission scheme that transmits power to a wireless power receiver located at a remote location by applying low-power energy to the RF signal.

On the other hand, heat may be generated in an electronic device including a wireless power transmitter, a battery powered by the wireless power receiver, or a wireless power receiver while wireless charging is performed, and the temperature of the wireless power transmitter or the wireless power receiver may be set to a predetermined level The wireless charging system may stop wireless charging.

Thereafter, the wireless charging can be resumed once the temperature of the wireless power transmitter or the wireless power receiver is lowered. The international standards bodies in connection with the wireless charging system may initiate specific conditions and points of time to resume wireless charging with respect to the wireless power transmitter And is not.

Accordingly, there is a need for a specific control method of a wireless power transmitter that takes into account the conditions under which the wireless power transmitter can resume wireless charging, or the point at which wireless charging can be resumed.

It is an object of the present invention to provide a method of controlling a wireless power transmitter and a wireless power transmitter.

The present invention provides a method of controlling a wireless power transmitter including a condition for monitoring the temperature of the wireless power transmitter and for resuming wireless charging in consideration of the degree of cooling of the wireless power transmitter.

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.

According to an aspect of the present invention, there is provided a method of controlling a wireless power transmitter, the method comprising: receiving a power transmission interruption packet from a wireless power receiver; Stopping the power transmission upon receiving the power transmission stop packet and measuring an off temperature at the time of receiving the power transmission stop packet; Calculating a temperature difference between the stop temperature and a re-measurement temperature at a time point when the first time has elapsed; And resuming power transmission to the wireless power receiver if the temperature difference satisfies a retransmission condition; . ≪ / RTI >

According to an embodiment, measuring the interruption temperature may include stopping power transmission and driving a cooling fan.

According to an embodiment, the step of resuming the power transmission comprises: stopping the driving of the cooling fan if the temperature difference satisfies the retransmission condition; . ≪ / RTI >

According to an embodiment of the present invention, the step of driving the cooling fan includes: varying a driving speed of the cooling fan according to the temperature difference; . ≪ / RTI >

According to an embodiment, the step of measuring the interruption temperature comprises the steps of: measuring the interruption temperature using a temperature sensor disposed in or within the predefined distance from the active area; Wherein the active region may include an area where the wireless power receiver is stationary.

The method may further include generating a digital zip signal or resuming power transmission at a point of time when a second time elapses from a point of time when the power transmission interruption packet is received.

According to an embodiment, the step of resuming the power transmission comprises: generating a digital zipping signal within a predetermined time; . ≪ / RTI >

According to an embodiment, the retransmission condition may be satisfied if the temperature difference is above a threshold temperature.

According to an embodiment, the step of resuming the power transfer comprises: determining the threshold temperature from the threshold temperature table according to the suspended temperature; . ≪ / RTI >

According to the embodiment, at the normal temperature, the interruption temperature included in the critical temperature table and the critical temperature may have a certain ratio.

According to an embodiment, the threshold temperature may be at least 5 degrees.

According to an embodiment, the step of measuring the interruption temperature comprises: stopping generation of the analog and digital signals for a third time; . ≪ / RTI >

According to the embodiment, the present invention can provide a computer-readable recording medium on which a program for executing the above-described method is recorded.

According to another aspect of the present invention, there is provided a wireless power transmitter including: a communication unit for receiving a power transmission interruption packet from a wireless power receiver; And a controller for stopping the power transmission upon receiving the power transmission stop packet and measuring the stop temperature at the time of receiving the power transmission stop packet. Wherein the controller calculates a temperature difference between the interrupted temperature and a remeasurement temperature at a point of time when the first time elapses and resumes power transmission to the wireless power receiver if the temperature difference satisfies a retransmission condition have.

According to an embodiment, a cooling fan; And the control unit may drive the cooling fan when the power transmission is interrupted.

According to the embodiment, when the temperature difference satisfies the retransmission condition, the control unit can stop the driving of the cooling fan.

According to the embodiment, the controller may vary the driving speed of the cooling fan according to the temperature difference.

A temperature sensor for measuring the interruption temperature, according to an embodiment; Wherein the temperature sensor is disposed in an active area or within a predetermined distance from the active area and the active area may include an area where the radio power receiver is mounted.

According to an embodiment, the controller may generate a digital zip signal or resume power transmission at a time point when a second time elapses after receiving the power transmission interrupt packet.

According to the embodiment, when the temperature difference satisfies the retransmission condition, the controller may generate a digital signal within a preset time.

According to an embodiment, the retransmission condition may be satisfied if the temperature difference is above a threshold temperature.

According to the embodiment, the control section can determine the threshold temperature from the threshold temperature table according to the stop temperature.

According to the embodiment, at the normal temperature, the interruption temperature included in the critical temperature table and the critical temperature may have a certain ratio.

According to an embodiment, the threshold temperature may be at least 5 degrees.

According to the embodiment, the control unit may stop the generation of the analog and digital signals for the third time.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, And can be understood and understood.

The effect of the control method of the wireless power transmitter and the wireless power transmitter according to the embodiment will be described as follows.

First, one embodiment may specify a specific point in time to resume wireless charging and may resume wireless charging quickly through wireless charging resume at this point.

Second, one embodiment may specify the resumption time of the wireless charging in consideration of the state of the wireless power transmitter, and may perform power transfer resumption with a consistent rule regardless of the wireless power receiver which may have various kinds or types have.

Third, in one embodiment, the wireless charging can be resumed more quickly by cooling the wireless power transmitter quickly using the cooling fan in the state where the wireless charging is interrupted.

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

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. It is to be understood, however, that the technical features of the present invention are not limited to the specific drawings, and the features disclosed in the drawings may be combined with each other to constitute a new embodiment.

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 a wireless power transmission procedure according to an embodiment of the present invention.

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

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

7 is a diagram for explaining a packet format transmitted and received between a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention.

8 is a view for explaining the types of packets that a wireless power receiver can transmit in a ping stage according to an embodiment of the present invention.

9 is a view for explaining the types of packets that the wireless power receiver can transmit in the power transmission step according to an embodiment of the present invention.

10 is a flowchart illustrating a method of controlling a wireless power transmitter according to an embodiment of the present invention.

A method of controlling a wireless power transmitter according to an exemplary embodiment of the present invention includes: receiving a power transmission stop packet from a wireless power receiver; Stopping the power transmission upon receiving the power transmission stop packet and measuring an off temperature at the time of receiving the power transmission stop packet; Calculating a temperature difference between the stop temperature and a re-measurement temperature at a time point when the first time has elapsed; And resuming power transmission to the wireless power receiver if the temperature difference satisfies a retransmission condition; . ≪ / RTI >

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.

Also, suffixes " modules " and " parts " for the components used in the following description may be implemented in hardware components - including, for example, circuit elements, microprocessors, memories, sensors, This is only one embodiment, and some or all of the components may be implemented in software.

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.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. That is, within the scope of the present invention, all of the components may be selectively coupled to one or more of them. In addition, although all of the components may be implemented as one independent hardware, some or all of the components may be selectively combined to perform a part or all of the functions in one or a plurality of hardware. As shown in FIG. The codes and code segments constituting the computer program may be easily deduced by those skilled in the art. Such a computer program can be stored in a computer-readable storage medium, readable and executed by a computer, thereby realizing an embodiment of the present invention. As the storage medium of the computer program, a magnetic recording medium, an optical recording medium, a carrier wave medium, or the like may be included.

It is also to be understood that the terms such as " comprises, " " comprising, " or " having ", as used herein, mean that a component can be implanted unless specifically stated to the contrary. But should be construed as including other elements. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Commonly used terms, such as predefined terms, should be interpreted to be consistent with the contextual meanings of the related art, and are not to be construed as ideal or overly formal, unless expressly defined to the contrary.

In describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected to or connected to the other component, It should be understood that an element may be "connected," "coupled," or "connected."

In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

Generally, a wireless power transmitter and a wireless power receiver that constitute a wireless power system can exchange control signals or information through in-band communication or Bluetooth low energy (BLE) communication. Here, the in-band communication and the BLE communication can be performed by a pulse width modulation method, a frequency modulation method, a phase modulation method, an amplitude modulation method, an amplitude and phase modulation method, and the like. For example, the wireless power receiver can transmit various control signals and information to the wireless power transmitter by generating a feedback signal by switching on / off the current induced through the reception coil in a predetermined pattern. The information transmitted by the wireless power receiver may include various status information including received power intensity information. At this time, the wireless power transmitter can calculate the charging efficiency or the power transmission efficiency based on the received power intensity information.

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. For example, the wireless power transmission standard may include, but is not limited to, electromagnetic induction standard techniques as defined in the Wireless Power Consortium (WPC) and Power Matters Alliance (WPC) standards bodies.

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 one or more transmitters.

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 30 Lt; / RTI > According to an embodiment, the power that the wireless power transmitting terminal 10 transmits to the wireless power receiving terminal 20 can be performed by transmitting and receiving a power signal.

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 the in-band communication, when the power signal 41 transmitted by the wireless power transmitting terminal 10 is received by the wireless power receiving terminal 20, the wireless power receiving terminal 20 modulates the received power signal, (42) may be transmitted to the wireless power transmitting terminal (10).

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 wireless power transmitting terminal 10 is not limited to the wireless power receiving terminal 20 It may be to transmit information.

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.

According to the embodiment, the wireless power receiving terminal 20 can acquire the overheat information of the battery of the electronic device 30. [ Specifically, the wireless power receiving terminal 20 transmits power to the wireless power transmitting terminal 10 due to overheating of the wireless power receiving terminal 20 itself, overheating of the electronic device 30, or overheating of the battery included in the electronic device 30. [ The wireless charging can be stopped through the interruption request of transmission of the signal.

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 devices connectable to one wireless power transmitting terminal 10 is based on at least one of the required power for each wireless power receiving device, the battery charging status, the power consumption of the electronic device, Can be determined adaptively.

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 devices connected to the wireless power receiving terminal 20 is adaptively set based on the required power of the wireless power receiving terminal 20, the battery charging state, the power consumption amount of the electronic device, 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. The sensing signal transmission procedure according to another embodiment may be performed only in a first order (or one time).

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 a wireless power transmission procedure.

Referring to FIG. 4, power transmission from a transmitter to a receiver according to an embodiment of the present invention includes a selection phase 410, a ping phase 420, an Identification and Configuration Phase A Negotiation Phase 440, a Calibration Phase 450, a Power Transfer Phase 460 and a Renegotiation Phase 470. In this case,

The selection step 410 may include steps that are transient, e.g., S402, S404, S408, S410 and S412, when a specific error or a specific event is detected while initiating a power transfer or maintaining a power transfer . 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 has been placed on the interface surface, it can transition to the zipping step 420.

For example, in a selection step 410, the transmitter transmits an analog ping signal of a very short pulse and, based on the current variation of the transmit coil or the primary coil, ) Of the object. Here, the active area may mean an area where wireless charging is possible on the transmitter.

According to an embodiment, the active area may be defined as a portion of an interface included in a wireless power transmitter in which a sufficiently high flux (power signal) can reach a wireless power receiver.

According to an embodiment, the active region may include a region where the radio power receiver is mounted, and the active region may include a region where the transmit coil is disposed.

As another example, in a selection step 410, the transmitter may detect whether an object is present in the active area of the interface surface using the provided sensor. For example, the sensor may include a Hall sensor, a pressure sensor, a capacitance sensor, a current sensor, a voltage sensor, a light sensor, and the like. At least one sensor may be used to detect whether a conductive object is disposed in the active area .

When the transmitter senses an object, it may enter a zip stage 420 to wake up the receiver and send a digital ping to identify the sensed object as a wireless power receiver. If the sender does not receive a response signal to the digital ping (e. G., A signal strength packet) from the receiver at step 420, then the receiver may transition back to step 410 again. Also, at the step 420, the transmitter may transition to the selection step 410 upon receipt of a signal indicating that the power transmission is complete from the receiver, i.e., a charge complete packet.

Once the ping stage 420 is complete, the transmitter may transition to an identification and configuration step 430 for identifying the receiver and collecting receiver configuration and status information.

In addition, in the identifying and configuring step 430, the sender may determine whether an unexpected packet is received, a desired packet is received for a predefined period of time (time out), a packet transmission error, If the transfer contract is not established (no power transfer contract), the transition to the selection step 410 can be made.

The transmitter may determine whether an entry to the negotiation step 440 is necessary based on the negotiation field value of the configuration packet received in the identification and configuration step 430. [

The receiver can be classified into a base power profile and an extended power profile according to a power level that can be received.

The reference power profile is applied to a wireless power transmitter capable of transmitting power of about 5 W or less and a wireless power receiver capable of receiving power of about 5 W or less, A power transmitter and a power receiver capable of receiving power in excess of 5 W. The wireless power transmitter determines the allowable power (power level) that the wireless power receiver can be provided according to the negotiation field included in the configuration packet .

A receiver with a defined power profile may perform some foreign object detection procedures (some functions of the FOD Extensions) prior to entering the power transfer phase. On the other hand, the receiver having the reference power profile can not perform the foreign matter detection procedure before entering the power transmission step.

As the wireless power reception performance of a receiver is improved, high power reception becomes possible, and accordingly, the function of detecting a foreign object placed in a charging area becomes more important. The receiver sets the negotiation field to 1 to perform the foreign matter detection procedure before the power transmission step and improve the foreign matter detection performance in the power transmission step through the correction step which will be described later.

When the transmitter receives the configuration packet with the negotiation field set to '1' from the receiver, it can send a normal response (ACK response) to the receiver to enter the negotiation phase.

When the transmitter and the receiver enter the negotiation phase according to the configuration packet and the normal response, the transmitter and the receiver can perform predetermined foreign matter detection procedures. In the negotiation phase, the receiver transmits the FOD Status Packet at least once to the transmitter. The transmitter receiving the FOD Status Packet can determine whether or not a foreign object exists by using at least one foreign substance detection method which will be described later. The transmitter may send an ACK / NACK response to the receiver according to the determination result of the presence of the foreign substance.

Alternatively, if predefined information is not received or an error occurs in the FOD Status Packet, the transmitter may send a non-defined response (ND).

As a result of the presence or absence of a foreign substance, if the foreign object is not detected, the transmitter can transmit an ACK response. Also, if a foreign object is detected, the transmitter can send a NACK response.

As an example, if the receiver receives a NACK response, the receiver may itself limit the required power parameter so that it does not require more than 5 W of power to the transmitter. In another example, if the receiver receives a NACK response, it may send a predetermined control message to the transmitter requesting power interruption, negotiation abort. If the transmitter has sent a NACK response, the transmitter may revert to the selection step 410 within a certain amount of time, regardless of additional communication from the receiver.

On the other hand, if no foreign object is detected, the transmitter may complete the negotiation step 440 for the transmit power and may enter the power transfer step 460 via the correction step 450.

In detail, if a foreign object is not detected, the transmitter can receive information about the strength of the received power from the receiver in the correcting step 450 (hereinafter referred to as received power intensity information for convenience of explanation).

For example, the transmitter may include a case, battery, and other circuitry of the electronic device 30 that includes the Friendly FO of the receiver by comparing the intensity of the power currently being delivered with the received power intensity, Can be calculated.

In the power transfer step 460, the transmitter determines whether an unexpected packet is received, 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, or an end power transfer due to overheating or charging completion, the selection step 410 may be entered.

Further, in the power transfer step 460, the transmitter may transition to the renegotiation step 470 if it is necessary to reconfigure the power transfer contract according to the transmitter state change or the like.

The receiver may also transition to renegotiation step 470 if it needs to reconfigure the power transmission contract based on the received power state or the like. At this time, if the renegotiation is normally completed, the transmitter may return to the power transmission step 460. [

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 transmittable power, information on the maximum number of receivers, etc., and the receiver status information may include information on the requested power and the like.

On the other hand, if the wireless power transmitter receives a power down packet due to overheating from the wireless power receiver in power transfer step 460, then the condition that the wireless power receiver does not enter selection step 410 during the time it is cooled need.

In a selection step 410, the wireless power transmitter may generate a digital zip signal, which may generate heat in the wireless power transmitter when generating the digital zip signal and generate heat when receiving the digital zip signal in the wireless power receiver. It is because.

In one embodiment, the wireless power transmitter may suspend transmission of power for a predetermined period of time required for cooling from the point of time of receipt upon receipt of the power down packet. The type, size, and type of the wireless power receiver may vary and the predetermined time taken for cooling may be different for each wireless power transmitter.

Accordingly, when the wireless power transmitter receives a power transmission interruption packet due to overheating, there is a need to resume the power transmission based on the temperature at which the wireless power transmitter is cooled without reference to the time required for cooling And will be described in detail with reference to FIG.

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

5, the wireless power transmitter 500 includes a power conversion unit 510, a power transmission unit 520, a communication unit 530, a control unit 540, a sensing unit 550, and a temperature control unit 570, As shown in FIG. It should be noted that the configuration of the wireless power transmitter 500 described above is not necessarily an essential configuration, and may be configured to include more or less components.

As shown in FIG. 5, when the DC power is supplied from the power supply unit 560, the power conversion unit 510 may convert the DC power into AC power of a predetermined intensity.

The power converter 510 may include a DC / DC converter 511, an inverter 512, and a frequency generator 513. Here, the inverter 512 may be a half bridge inverter or a full bridge inverter. However, the present invention is not limited thereto, and a circuit configuration capable of converting DC power into AC power having a specific operating frequency is sufficient.

The DC / DC converting unit 511 may convert DC power supplied from the power supply unit 550 into DC power having a specific intensity according to a control signal of the controller 540.

At this time, the sensing unit 550 may measure the voltage / current of the DC-converted power and provide it to the controller 540.

In addition, the sensing unit 550 may measure the internal temperature of the wireless power transmitter 500 and may provide the measurement result to the controller 540 in order to determine whether overheating occurs.

In one embodiment, the sensing unit 550 may include a temperature sensor capable of measuring the internal temperature of the wireless power transmitter 500, for example, the temperature sensor may include a thermistor.

The temperature sensor may be disposed in an area where the wireless power receiver is mounted, or in an area spaced a predetermined distance from the area where the wireless power receiver is mounted. Alternatively, the temperature sensor may be located in a configuration that generates the most heat within the wireless power transmitter 500 and may include a converter (e. G., A buck converter) that converts the magnitude of the voltage or current, ) Or a regulator (Low Drop Out (LDO)).

In one embodiment, the temperature sensor can measure the internal temperature of the wireless power transmitter 500 at the point of time of receiving the power down packet from the wireless power receiver, and can continue monitoring by measuring the internal temperature every predetermined period have.

For example, the control unit 540 may be configured to block power supply from the power supply unit 550 adaptively based on the voltage / current / temperature value measured by the sensing unit 550, or to supply power to the amplifier 512 You can block things. To this end, a power cutoff circuit may be further provided at one side of the power conversion unit 510 to cut off power supplied from the power supply unit 550 or to cut off power supplied to the amplifier 512.

The inverter 512 may convert the DC / DC converted DC power into AC power based on the reference AC signal generated by the frequency generator 513. [ At this time, the frequency of the reference AC signal - that is, the operating frequency - can be dynamically changed according to the control signal of the controller 540. The wireless power transmitter 500 according to an embodiment of the present invention may adjust the intensity of the transmitted power by adjusting the operating frequency.

For example, the control unit 540 may receive the power reception status information and / or the power control signal of the wireless power receiver through the communication unit 530 and may receive the power reception status information or the power control signal And to dynamically control the frequency generator 513 to generate the determined operating frequency.

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 520 may be configured to include a multiplexer 521 (or a multiplexer) and a transmitting coil unit 522. Here, the transmission coil section 522 may be composed of first to n-th transmission coils. In addition, the power transmitting unit 520 may further include a carrier generator (not shown) for generating a specific carrier frequency for power transmission. In this case, the carrier generator may generate a specific carrier frequency for mixing with the output AC power of the inverter 512 transmitted through the multiplexer 521.

It should be noted that one embodiment of the present invention may have different frequencies of AC power delivered to each transmit coil. 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.

The multiplexer 521 may perform a switch function to transmit AC power to the transmission coil selected by the controller 540. [ The control unit 540 may select a transmission coil to be used for power transmission to the corresponding wireless power receiver based on the signal strength indicator received for each transmission coil.

The controller 540 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 three wireless power receivers-i. E., First through third wireless power receivers-are each identified through three different transmit coils-i. E., First through third transmit coils-in wireless power transmitter 500 , The controller 540 controls the multiplexer 521 to control the AC power to be transmitted only through a specific transmission coil in a specific time slot.

At this time, the amount of power transmitted to the corresponding wireless power receiver can be controlled according to the length of the time slot allocated for each transmission coil, but this is only one embodiment. DC power of the DC / DC converter 511 to control the transmission power of each wireless power receiver.

The control unit 540 may control the multiplexer 521 so that the detection signals may be sequentially transmitted through the first through n'th transmission coils 522 during the first detection signal transmission procedure. At this time, the control unit 540 can identify the time at which the detection signal is transmitted using the timer 555. When the time of the transmission of the spoofing signal arrives, the control unit 540 controls the multiplexer 521 to output a detection signal It can be controlled to be transmitted. For example, the timer 550 can send a specific event signal to the control unit 540 at predetermined intervals during the ping transmission step, and the control unit 540 controls the multiplexer 521 every time the corresponding event signal is detected So that the digital ping can be transmitted through the corresponding transmission coil.

In addition, the control unit 540 transmits a predetermined transmission coil identifier for identifying a signal strength indicator (Signal Strength Indicator) through a transmission coil from the demodulation unit 532 during the first detection signal transmission procedure, Lt; / RTI > received signal strength indicator.

For example, in the second detection signal transmission process, the controller 540 may control the multiplexer 521 to transmit the detection signal only through the transmission coil (s) on which the signal strength indicator is received during the first detection signal transmission procedure Control.

In addition, the control unit 540 can identify the cause of the power transmission interruption included in the power transmission stop packet from the wireless power receiver in the power transmission step received from the demodulation unit 532. [ The reasons for the interruption of the power transmission include Charge Complete, Internal Fault, Over Temperature, Over Voltage, Over Current, Battery Failure, Reconfigure, No Response, Noise Current, and the like.

If overheating of the wireless power receiver is the reason for the above reasons, the controller 540 may immediately stop transmitting power for a sufficient time to cool the heat generated inside the wireless power transmitter 500. Sufficient time to cool down may be set differently for each wireless power transmitter 500.

At this time, the control unit 540 may generate a digital ping signal while transitioning from the power transmitting step to the selecting step.

In addition, the controller 540 can monitor the internal temperature of the wireless power transmitter by the temperature sensor.

The control unit 540 can calculate the temperature difference between the restart temperature measured by the temperature sensor and the re-measurement temperature at the point of time when the preset time passes after receiving the power transmission interrupt packet, and when the temperature difference satisfies the retransmission condition The power transmission to the wireless power receiver can be resumed.

The cooling operation may be performed by the temperature regulator 570 for a predetermined period of time from the time when the power transmission interruption packet is received, and the predetermined period of time may be, for example, 5 seconds.

For example, the internal temperature of the wireless power transmitter may be 60 [deg.] C at the time the wireless power transmitter 500 receives the power interruption packet, and 58 [deg.] C after 5 seconds. The temperature difference may then indicate the degree of cooling of the internal temperature of the wireless power transmitter. If the temperature difference indicating the degree of cooling is smaller than the threshold temperature (for example, 30 DEG C), the control unit 540 can determine that the degree of cooling is insufficient and can continue to hold the power transmission interrupted state. If the re-measurement temperature in the wireless power transmitter 500 is 20 ° C due to continuous monitoring, the controller 540 determines that the retransmission condition is satisfied when the temperature difference (40 ° C) is equal to or higher than the threshold temperature (30 ° C) Power transmission to the power receiver can be resumed.

The communication unit 530 may include at least one of a modulation unit 531 and a demodulation unit 532.

The modulator 531 modulates the control signal generated by the controller 540 and transmits the modulated signal to the multiplexer 521. 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 532 can demodulate the detected signal and transmit the demodulated signal to the controller 540 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.

The demodulation unit 532 may identify the signal from which the demodulated signal is received and may provide the control unit 540 with a predetermined transmission coil identifier corresponding to the identified transmission coil.

 The demodulation unit 532 demodulates the signal received through the transmission coil 523 and transmits the demodulated signal to the control unit 540. 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 500 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 500 may transmit wireless power using the transmit coil portion 522, as well as exchange various control signals and status information with the wireless power receiver via the transmit coil portion 522 . As another example, a separate coil corresponding to each of the first to n-th transmission coils of the transmission coil part 522 may be additionally provided in the wireless power transmitter 500, and wireless power It should be noted that it may also perform in-band communication with the receiver.

In the description of FIG. 5, the wireless power transmitter 500 and the wireless power receiver perform in-band communication. However, this is merely one example, 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.

5, the power transmission unit 520 of the wireless power transmitter 500 includes a multiplexer 521 and a plurality of transmission coils 522, but this is only one embodiment, It should be noted that the power transmission unit 520 according to the embodiment may be composed of one transmission coil.

The temperature regulating unit 570 may include a cooling fan or the like, and may drive the cooling fan to reduce heat generated internally. The temperature controller 570 can prevent a dangerous situation caused by the high temperature inside the wireless power transmitter and prevent the loss of the internal configuration included in the wireless power transmitter.

The temperature regulator 570 may be driven to cool the internal heat that may occur together when the power signal is generated in the power transmission step. However, the present invention is not limited to the power transmission step, but may be operated to cool the internal heat of the wireless power transmitter 500 even in the selection step, the ping step, the identification and configuration step, and the negotiation step. According to one embodiment, even when receiving a power transmission interruption packet due to overheating from the wireless power receiver, the power transmission can be stopped and the cooling fan can be driven to cool the wireless power transmitter. There may be several causes for the overheating of the wireless power receiver, and the heat generated from the wireless power transmitter may cause overheating of the wireless power receiver. Depending on the result, the cooling of the wireless power transmitter may also have the effect of cooling the wireless power receiver located in contact with the wireless power transmitter.

In one embodiment, the temperature control unit 570 may set the driving conditions regardless of each step of the wireless transmission.

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

6, the wireless power receiver 600 includes a receiving coil 610, a rectifier 620, a DC / DC converter 630, a load 640, a sensing unit 650, 660, and a main control unit 670, as shown in FIG. Here, the communication unit 660 may include at least one of a demodulation unit 661 and a modulation unit 662.

Although the wireless power receiver 600 shown in the example of FIG. 6 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 660 according to another embodiment of the present invention may provide short-range bidirectional communication through a frequency band different from the frequency band used for wireless power signal transmission.

AC power received through the receiving coil 610 may be transmitted to the rectifying unit 620. [ The rectifier 620 may convert the AC power to DC power and transmit it to the DC / DC converter 630. The DC / DC converter 630 may convert the intensity of the rectifier output DC power to a specific intensity required by the load 640 and then deliver it to the load 640.

The sensing unit 650 may measure the intensity of the DC power output from the rectifier 620 and may provide it to the main control unit 670. Also, the sensing unit 650 may measure the intensity of the current applied to the reception coil 610 according to the wireless power reception, and may transmit the measurement result to the main control unit 670. Also, the sensing unit 650 may measure the internal temperature of the wireless power receiver 600 and provide the measured temperature value to the main control unit 670.

For example, the main control unit 670 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, when an overvoltage is generated, a predetermined packet indicating that an overvoltage has occurred can be generated and transmitted to the modulating unit 662. Here, the signal modulated by the modulating unit 662 may be transmitted to the wireless power transmitter 600 through the receiving coil 610 or a separate coil (not shown).

The main control unit 670 may determine the overheating by measuring the internal temperature according to the heat generated in the configuration shown in FIG. 6 or may measure the temperature of the battery included in the electronic device or the electronic device that supplies power to the wireless power receiver So that overheating can be judged. The main control unit 670 can determine whether the temperature is overheated by comparing the predetermined reference temperature with the measured temperature.

When the main control unit 670 determines that the power is overheated, the main control unit 670 may transmit the power transmission stop packet to the wireless power transmitter in the ping step or the power transmission step to stop the power transmission. At this time, the main control unit 670 may transmit the power transmission interruption packet due to overheating.

The main control unit 670 can 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. When receiving the detection signal, the signal intensity indicator corresponding to the detection signal is received by the modulation unit 662 To be transmitted to the wireless power transmitter 600 via the wireless network.

The demodulation unit 661 demodulates the AC power signal between the reception coil 610 and the rectifier 620 or the DC power signal output from the rectifier 620 to identify whether or not the detection signal is received, (670). ≪ / RTI > At this time, the main control unit 670 may control the signal intensity indicator corresponding to the detection signal to be transmitted through the modulation unit 662. [

7 is a diagram for explaining a packet format transmitted and received between a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention.

Referring to FIG. 7, a packet format 700 used for information exchange between a wireless power transmitter and a wireless power receiver includes a preamble (Preamble) for identifying a synchronization start for demodulating the packet, A header 720 field for identifying the type of the message included in the packet, a message 730 for transmitting the content of the packet (or payload) And a check sum (740) field for identifying whether or not an error has occurred.

As shown in FIG. 7, the packet receiving end may identify the size of the message 730 included in the packet based on the header 720 value.

In addition, the header 720 may be defined for each step of the wireless power transmission procedure, and some values of the header 720 may be defined as different types of messages although they are the same value at different stages. For example, the header value corresponding to the end power transfer of the pinging step and the power transmission end of the power transmitting step may be equal to 0x02.

The message 730 includes data to be transmitted at the transmitting end of the packet. For example, the data contained in the message 730 field may be, but is not limited to, a report, a request, or a response to the other party.

The packet 700 according to another embodiment of the present invention may further include at least one of transmitting end identification information for identifying a transmitting end that transmitted the packet and 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.

8 is a view for explaining the types of packets that a wireless power receiver can transmit in a ping stage according to an embodiment of the present invention.

As shown in FIG. 8, in the step of pinging, the wireless power receiving apparatus can transmit a signal strength packet or a power transmission stop packet.

Referring to reference numeral 801 in FIG. 8, a message format of a signal strength packet according to an exemplary embodiment may include a signal strength value having a size of 1 byte. The signal strength value may indicate the degree of coupling between the transmitting coil and the receiving coil and may be calculated based on the rectifier output voltage in the digital ping section, the open circuit voltage measured in the output blocking switch, Lt; / RTI > The signal strength value may range from a minimum of 0 to a maximum of 255 and may have a value of 255 if the actual measured value for a particular variable is equal to the maximum value of that variable (Umax). For example, the signal strength value may be calculated as U / Umax * 256.

Referring to FIG. 8, the message format of the power transmission stop packet according to an exemplary embodiment may include an end power transfer code having a size of 1 byte.

The reasons why the wireless power receiving apparatus requests the wireless power transmitter to stop the power transmission include charging completion, internal fault, overtemperature, overvoltage, overcurrent, battery But is not limited to, battery failure, reconfiguration and no response, noise current, and the like. It should be noted that the power transmission interruption code may be further defined in response to each new power transmission interruption reason.

Charging complete can be used to indicate that the charging of the receiver battery is complete. In detail, the wireless power receiver may transmit a power transmission interruption code for reasons of charging completion when it determines that the battery included in the wireless power receiver or the electronic appliance is fully charged.

When the wireless power transmitter receives a power transmission interruption code that includes a charging completion, the wireless power transmitter displays an output (e.g., " buffer ") indicating that charging is complete via a user interface included in the wireless power receiver .

The wireless power transmitter may not generate the analog ping signal generated in the selection step and the digital ping signal generated in the ping stage after receiving the power transmission interruption code due to the completion of charging. The wireless power transmitter may not enter the selection and ping stages for a predetermined time.

Internal errors can be used when a software or logical error in the internal operation of the receiver is detected.

Overheating / overvoltage / overcurrent can be used when the measured temperature / voltage / current value at the receiver exceeds the defined threshold for each.

The wireless power transmitter may not generate the analog ping signal generated in the selection step and the digital ping signal generated in the ping stage after receiving the power transmission interruption code due to overheating. The wireless power transmitter may not enter the selection and ping stages for a predetermined time.

The wireless power receiver may not transmit a packet containing a signal strength value or a packet containing a power transmission interruption code to the wireless power transmitter even after receiving the digital transmission signal, . The wireless power receiver may not enter the selection and ping stages for a predetermined time.

Battery damage can be used if it is determined that there is a problem with the receiver battery.

Reconfiguration can be used when renegotiation is required for power transmission conditions.

No response can be used if the transmitter's response to the control error packet - meaning increasing or decreasing the strength of the power - is judged to be unhealthy.

The noise current, which is different from the overcurrent, can be used when the noise current value measured at the receiver exceeds the defined threshold value due to switching noise in the inverter.

Referring to FIG. 9, in the power transmission step, a packet that can be transmitted by the wireless power receiving apparatus includes a control error packet, an end power transfer packet, a received power packet, A packet (Charge Status Packet), a packet defined by a manufacturer, and the like.

Reference numeral 901 denotes a message format of a control error packet composed of a 1-byte control error value. Here, the control error value may be an integer value ranging from -128 to +127. If the control error value is negative, the transmission power of the radio power transmission apparatus decreases, and if it is positive, the transmission power of the radio power transmission apparatus can be increased.

Reference numeral 902 denotes a message format of a control error packet composed of a 1-byte power transmission interruption code (End Power Transfer Code). Here, the power transmission interruption code will be replaced with the description of FIG. 8 described above.

Reference numeral 903 denotes a message format of a received power packet composed of a 1-byte received power value. Here, the received power value may correspond to the average rectifier received power value calculated during a predetermined period. The actual received power (P _received ) may be calculated based on the Maximum Power and Power Class included in the configuration packet 1501. As an example, the actual received power may be calculated by (received power value / 128) * (maximum power / 2) * (10 ^{power rating} ).

Reference numeral 904 denotes a message format of a Charge Status Packet consisting of a 1-byte Charge Status Value. The charge state value may indicate the battery charge amount of the wireless power receiving device. For example, the charge state value 0 means a completely discharged state, the charge state value 50 may mean a 50% charge state, and the charge state value 100 may mean a full charge state. If the wireless power receiving device does not include a rechargeable battery or can not provide charge state information, the charge state value may be set to OxFF.

10 is a flowchart illustrating a method of controlling a wireless power transmitter according to an embodiment of the present invention.

Referring to FIG. 10, the wireless power transmitter may receive a power transmission interruption packet from a wireless power receiver (S1010).

The wireless power receiver may transmit a power transmission shutdown packet due to over temperature in the power transmission stage. The wireless power receiver can determine the overheating by measuring the internal temperature according to the heat generated in the configuration shown in FIG. 6, and the temperature of the battery included in the electronic device or the electronic device that supplies power to the wireless power receiver is measured Overheating can be judged.

Upon receiving the power transmission interruption packet, the wireless power transmitter can stop the power transmission to the wireless power receiver and measure the interruption temperature at the time of receiving the power transmission interruption packet (S1020).

At this time, the wireless power transmitter can determine whether the power transmission interruption included in the power transmission interruption packet is caused by overheating, and can measure the internal temperature of the wireless power transmitter as the interruption temperature only in case of overheating.

On the other hand, when the wireless power transmitter receives the power transmission stop packet, it can stop the generation of the power signal generated in the transmission coil and stop the generation of the analog and digital signals for a predetermined time. This is because the heat generated from the internal configuration of the wireless power transmitter may interfere with the cooling in the process of re-generating the analog and digital signals, and the wireless power receiver receiving the digital signal may generate a signal strength indicator To prevent the cooling from being disturbed by proceeding again to the identification and configuration step, the negotiation step, and the power transmission step by re-transmission.

The wireless power transmitter can determine the internal temperature of the wireless power transmission as a stop temperature using a temperature sensor located within a predefined distance from the active area or active area, The temperature sensor can be used to determine the temperature of the region where the highest temperature is determined in the wireless power transmitter to be the stop temperature.

According to an embodiment, the active region may include a region where the radio power receiver is mounted, and the active region may include a region where the transmit coil is disposed.

On the other hand, if the wireless power transmitter determines that the reason for the power transmission interruption included in the power transmission interrupt packet is due to overheating, it can drive the cooling fan, and the driving speed of the cooling fan can be changed have.

For example, if the stop temperature is high, the driving speed of the cooling fan can be increased to promote the cooling.

The wireless power transmitter may measure the remeasurement temperature inside the wireless power transmitter after a predetermined time has elapsed from the time of receiving the power transmission suspension packet (S1030). The wireless power transmitter can monitor the measured internal temperature using a temperature sensor at predetermined time intervals.

For example, the wireless power transmitter may measure the remeasurement temperature for a predetermined time (e.g., 5 seconds) from the point of time of receiving the power transmission interruption packet. The wireless power transmitter can calculate the temperature difference between the interrupted temperature and the re-measured temperature every time the re-measured temperature is measured (S1030).

The wireless power transmitter may determine whether to resume power transmission according to whether the temperature difference satisfies the retransmission condition (S 1040).

The temperature difference calculated by the wireless power transmitter can indicate the degree of cooling of the wireless power transmitter, and if the degree of cooling is high, the temperature difference can be large.

The retransmission condition can be satisfied when the calculated temperature difference is equal to or higher than a predetermined threshold temperature. In other words, the temperature difference indicates the degree of cooling, and the critical temperature may be a temperature that is a reference for resuming power transmission depending on the degree of cooling. Therefore, if the temperature difference is greater than the critical temperature, it can be determined that cooling has been performed to resume power transmission. However, if the temperature difference is less than the critical temperature, it is difficult to judge that cooling has been performed to resume power transmission. According to one embodiment, when the threshold temperature is 5 ° C or higher, power transfer can be resumed.

For example, if the interruption temperature of the wireless power transmitter is 60 ° C and the remeasurement temperature is 20 ° C at the time of receiving the power interruption packet, the wireless power transmitter can calculate the temperature difference to 40 ° C, Can be judged to have been performed. On the other hand, if the critical temperature is 35 占 폚, it can be judged that the retransmission condition is satisfied because the temperature difference is equal to or higher than the critical temperature. Conversely, if the temperature difference is 20 deg. C, it is difficult to judge that sufficient cooling has been performed because the temperature difference is smaller than the critical temperature, and it can be judged that the retransmission condition is not satisfied.

That is, if the temperature difference does not satisfy the retransmission condition (" NO " path in S1040), the remeasurement temperature can be measured every predetermined time period in the state where the power transmission is stopped. Conversely, when the temperature difference satisfies the retransmission condition (YES in S1040), the wireless power transmitter may resume power transmission (S1050).

The threshold temperature may be a predetermined value for the wireless power transmitter and may be calculated from the threshold temperature table previously stored in the wireless power transmitter according to the stop temperature.

The critical temperature is a value indicative of the degree of cooling which is a standard for restarting the power transmission, and the value may be changed depending on the stop temperature. For example, given the case of an interruption temperature of 90 ° C and a case of 60 ° C, the former may require relatively more cooling than the latter.

The threshold temperature table may be stored in advance in the wireless power transmitter based on experimentally calculated data at room temperature, and the stop temperature and the threshold temperature included in the threshold temperature table may have a predetermined ratio.

To resume power transmission, the wireless power transmitter may enter a selection stage to generate a digital zip signal or may immediately enter a power transfer stage to generate a power signal.

It can be determined that the wireless power transmitter is sufficiently cooled that the retransmission condition is satisfied, and the wireless power transmitter can stop driving the cooling fan.

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.

The present invention can be applied to a wireless charging field, and in particular, to a wireless power transmitter equipped with an overheating prevention function.

Claims (10)

1. A communication unit for receiving a power transmission interruption packet from the wireless power receiver; And

   A control unit for stopping the power transmission upon receiving the power transmission stop packet and measuring the stop temperature at the time of receiving the power transmission stop packet;

   / RTI >

   Wherein,

   Measuring a temperature difference between the termination temperature and a remeasurement temperature at a point of time when a first time elapses after receiving the power transmission interruption packet; and resuming power transmission to the wireless power receiver when the temperature difference satisfies a retransmission condition,

   Wireless power transmitter.
2. The method according to claim 1,

   A cooling fan;

   Further comprising:

   Wherein the control unit is operable to drive the cooling fan when the power transmission is interrupted,

   Wireless power transmitter.
3. 3. The method of claim 2,

   Wherein,

   And stopping the driving of the cooling fan when the temperature difference satisfies the retransmission condition,

   Wireless power transmitter.
4. 3. The method of claim 2,

   Wherein,

   Wherein the driving speed of the cooling fan is varied according to the temperature difference,

   Wireless power transmitter.
5. The method according to claim 1,

   A temperature sensor for measuring the interruption temperature;

   Further comprising:

   Wherein the temperature sensor comprises:

   Disposed within or within a predetermined distance from the active region,

   Wherein the active region comprises an area where the radio power receiver is stationary,

   Wireless power transmitter.
6. The method according to claim 1,

   Wherein,

   And stops generation of the analog and digital signals for a second time from the reception of the power transmission interruption packet

   Wireless power transmitter.
7. The method according to claim 1,

   Wherein,

   And generating a digital signal within a predetermined time when the temperature difference satisfies the retransmission condition,

   Wireless power transmitter.
8. The method according to claim 1,

   And the retransmission condition is satisfied when the temperature difference is equal to or higher than the threshold temperature,

   Wireless power transmitter.
9. 9. The method of claim 8,

   Wherein,

   Determining the critical temperature from the critical temperature table according to the interrupted temperature,

   Wireless power transmitter.
10. 10. The method of claim 9,

    Wherein the atmospheric temperature and the threshold temperature included in the threshold temperature table have a predetermined ratio,

    Wireless power transmitter.

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