JP6781563B2 - Power receiving device, control method, and program - Google Patents

Description

The present invention relates to wireless power transmission technology.

In recent years, devices having a wireless communication function and a wireless power transmission function have been studied. Patent Document 1 discloses a device having an NFC (Near Field Communication) communication function and a wireless power transmission function.

Japanese Unexamined Patent Publication No. 2014-07857

There is a problem that an electromagnetic wave (or a harmonic thereof) having a frequency used in wireless power transmission affects other wireless communication (for example, NFC), and the wireless communication cannot be performed normally.

The present invention has been made in view of the above problems, and an object of the present invention is to reduce interference of wireless power transmission with electromagnetic waves into other wireless communications.

In order to achieve the above object , the power receiving device according to the present invention uses a power receiving means for receiving power wirelessly from the power transmitting device and a first antenna for controlling the power supplied by the power receiving means to the load from the power transmitting device. By using a first communication means for performing communication for the purpose and a second antenna different from the first antenna, communication different from the communication for control of receiving the electric power supplied to the load from the power transmission device is performed. The transmission of the electric power supplied to the load is performed based on the communication means having the second communication means and the communication different from the communication for controlling receiving the electric power supplied to the load from the power transmission device. It has a control means for controlling the communication means so as to transmit a notification for limiting to the power transmission device, and the power receiving means and the first communication means are activated by the electric power received from the power transmission device. However, the power receiving means is smaller than the power supplied to the load while the second communication means performs communication different from the communication for controlling receiving the power supplied to the load from the power transmission device. It is characterized in that it receives electric power that can activate the power receiving means and the first communication means.

Interference with other wireless communications due to electromagnetic waves of wireless power transmission can be reduced.

A block diagram showing a configuration example of a power transmission device. The block diagram which shows the configuration example of the power receiving device. The figure which shows the arrangement example of an NFC antenna and a power transmission antenna. The figure which shows the example of the electric power transmitted from the power transmission part. A flowchart showing an example of the flow of processing executed by the power receiver. A sequence diagram showing an example of a processing flow in a wireless power transmission system.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In the present embodiment, a wireless power transmission system for transmitting power from the power transmitting device 100 to the power receiving device 200 by wireless power transmission will be described. When power is transmitted by wireless power transmission when at least one of the power transmitting device 100 and the power receiving device 200 or a surrounding device is performing wireless communication such as NFC, the wireless power transmission becomes the wireless communication. It may interfere. This can happen when a wireless power transfer system transmits as much power as tens of watts, while in wireless communication (such as NFC) the receiver receives a signal with as little power as a few milliwatts. For example, switching noise generated when a DC voltage is converted into an AC voltage in the switching circuit of the power transmission device 100 can be superimposed on the power transmitted in the wireless power transmission. In this case, the switching noise may interfere with a signal of a small power in wireless communication, and the signal may be distorted to deteriorate the communication quality. Therefore, when the power receiving device 200 according to the present embodiment detects that wireless communication such as NFC is being performed, it transmits a notification to the power transmission device 100 indicating that power transmission by wireless power transmission should be restricted. Hereinafter, the device configuration for performing such processing and the flow of processing will be described.

(Device configuration)
FIG. 1 is a block diagram showing a configuration example of the power transmission device 100 according to the present embodiment. The power transmission device 100 includes, for example, a control unit 101, a power supply 102, a power transmission unit 103, a communication unit 104, a power transmission antenna 105, an NFC 106, a timer 107, a memory 108, and an output unit 109.

The control unit 101 controls the entire device by, for example, executing a control program stored in the memory 108. The control unit 101 is, in one example, a CPU (Central Processing Unit). The control unit 101 can also use the memory 108 when storing the values of the variables acquired during the execution of the control program. Further, the control unit 101 can measure the time by using the timer 107. The power source 102 supplies electric power to the power transmitting unit 103 when the power transmitting device 100 transmits electric power to the power receiving device 200 by wireless power transmission. The power source 102 is, for example, a commercial power source or a battery.

The power transmission unit 103 converts DC power or AC power input from the power source 102 into AC power in the frequency band used for wireless power transmission, and generates electromagnetic waves transmitted to the power receiving device 200 via the power transmission antenna 105. Let me. In the present embodiment, the frequency of the AC power is different from the operating frequency of the NFC described later. For example, a frequency of about several hundred kHz is used for wireless power transmission, and the operating frequency of NFC is 13.56 MHz. The power transmission unit 103 outputs an electromagnetic wave for transmitting electric power to the power receiving device 200 from the power transmission antenna 105 based on the instruction of the control unit 101. Further, the power transmission unit 103 can control the intensity of the electromagnetic wave to be output by adjusting the voltage (transmission voltage) or current (transmission current) input to the power transmission antenna 105. As the transmission voltage or transmission current increases, the intensity of electromagnetic waves increases accordingly. Further, the power transmission unit 103 can control to stop the power transmission from the power transmission antenna 105 based on the instruction of the control unit 101.

The communication unit 104 performs control communication related to wireless power transmission with the communication unit 204 of the power receiving device 200. The communication unit 104 performs control communication in a form of superimposing on the electric power transmitted from the power transmission antenna 105 (for example, by modulating the electric power transmitted from the power transmission antenna 105).

The NFC 106 is a reader / writer compliant with the NFC (Near Field Communication) standard, and communicates with the NFC 202 of the power receiving device 200 in accordance with the NFC standard. The communication of the NFC 106 is performed via the NFC antenna, which is different from the power transmission antenna 105. Further, the communication performed by the NFC 106 is, for example, a communication for executing an application that is not related to the control communication of wireless power transmission.

The output unit 109 outputs various outputs to the user. Here, the output by the output unit 109 includes at least one such as a color change or blinking and lighting of an LED (Light Emitting Diode), a display on a screen, an audio output by a speaker, and a vibration output.

The power transmission device 100 does not have to be a device dedicated to power transmission, and may be, for example, a device such as a printer or a PC that can perform power transmission while having other functions.

FIG. 2 is a diagram showing a configuration example of the power receiving device 200 according to the present embodiment. The power receiving device 200 includes, for example, a first control unit 201, an NFC 202, a power receiving antenna 203, a communication unit 204, a power receiving unit 205, a second control unit 206, a charging unit 207, a battery 208, and a display unit 209. The first control unit 201 exists inside the NFC 202 in one example, and is connected to the power receiving unit 205 and the second control unit 206. The first control unit 201 can operate by the DC voltage obtained by rectifying the 13.56 MHz electromagnetic wave received from the NFC 106 of the power transmission device 100 by the NFC 202. Then, the first control unit 201 controls the operation of the NFC 202, and transmits / receives information between the power receiving unit 205 and the second control unit 206. The NFC 202 is an NFC tag compliant with the NFC standard, and communicates with the NFC 106 of the power transmission device 100 in accordance with the NFC standard. Further, the NFC 202 can be operated by the electric power supplied from the NFC 106, similarly to the first control unit 201. The communication of the NFC 202 is performed via an NFC antenna different from the power receiving antenna 203.

The power receiving antenna 203 is an antenna for receiving an electromagnetic wave transmitted from the power transmission device 100. The power receiving unit 205 obtains AC power by resonance generated in the circuit in the power receiving unit 205 by the electromagnetic wave received by the power receiving antenna 203. Then, the power receiving unit 205 converts the AC power into DC or AC power having a desired frequency, and supplies the converted power to the battery 209 or the charging unit 207 that charges the battery. The power receiving unit 205 may supply the received power to a load for purposes other than charging the battery 209. That is, the use of the received power is not limited to charging, and the received power can be supplied to various loads.

The communication unit 204 performs control communication of wireless power transmission with the power transmission device 100 via the power reception antenna 203 of the power reception device 200 (also via the power transmission antenna 105 of the power transmission device 100). The communication unit 204 can operate by receiving power supply from the power receiving unit 205. When the AC voltage input from the power receiving antenna 203 or the DC voltage converted from the AC voltage exceeds a certain value, the power receiving unit 205 receives, for example, sufficient power to start the power receiving unit 205 itself and the communication unit 204. In this case, control communication of wireless power transmission is performed via the communication unit 204.

The battery 209 stores the electric power received by the power receiving unit 205, and supplies at least the second control unit 206 with the electric power for the second control unit 206 to operate. The second control unit 206 may be, for example, a CPU that executes a control program stored in a memory (not shown) and controls the entire power receiving device 200. The output unit 208 outputs various outputs to the user. Here, the output by the output unit 208 includes at least one of LED color change or blinking and lighting, display on the screen, audio output by the speaker, vibration output, and the like.

FIG. 3 is a diagram showing an arrangement example of the power transmission antenna 105 in the power transmission device 100 and the antenna 300 of the NFC 106. As shown in FIG. 3, for example, the power transmission antenna 105 may be arranged so as to be surrounded by the antenna 300 of the NFC 106. The relationship between the power receiving antenna 203 in the power receiving device 200 and the NFC antenna in the NFC 202 is also assumed to be such that the power receiving antenna 203 is arranged so as to be surrounded by the NFC antenna, as in FIG. With such a configuration, when the power receiving device 200 is placed on the power transmitting device 100, it is possible to perform control communication and power transmission / reception in wireless power transmission as well as communication conforming to the NFC standard. The antenna arrangement in FIG. 3 is an example, and the antenna for wireless power transmission and the antenna for other wireless communication using a frequency different from that for wireless power transmission may be arranged at arbitrary positions. For example, transmission antennas (or power receiving antennas) for wireless power transmission may be arranged side by side in the immediate vicinity of the antenna for NFC.

FIG. 4 shows the electric power transmitted by the power transmission unit 103 of the power transmission device 100 via the power transmission antenna 105. In FIG. 4, the horizontal axis represents time and the vertical axis represents the magnitude of electric power. The power transmission device 100 periodically sends out a small amount of electric power 400 for detecting an object in order to detect the presence of an object in the power transmission range. The power transmission device 100 operates a detection unit (not shown) while transmitting the low power 400. The detection unit detects the voltage value or current value around the power transmission unit 103, or calculates the impedance obtained by dividing the detected voltage value by the detected current value, and the object exists in the power transmission range. Is detected. If an object exists within the power transmission range, the voltage value, current value, or impedance detected or calculated by the detector will be the same as when the object does not exist within the power transmission range due to the eddy current flowing through the object. Will show different values. That is, the power transmission device 100 can detect an object by detecting a change in voltage value, current value, or impedance around the power transmission unit 103.

When the power transmission device 100 detects a change in voltage value, current value, or impedance, the power transmission unit 103 transmits medium power 401, which is larger than small power. The medium power 401 may be a power sufficient to activate the power receiving unit 205 and the communication unit 204 of the power receiving device 200, but may not be large enough to charge the battery 209. While the medium power 401 is being transmitted, the power transmitting device 100 and the power receiving device 200 perform control communication such as authentication processing in the wireless power transmission system and negotiation of the transmitted power. When the transmission power negotiation is established between the power transmission device 100 and the power reception device 200, the power transmission unit 103 sends out a charging power 402 larger than the medium power as a result of the negotiation. In the present embodiment, the charging power 402 may affect the quality of NFC communication between the NFC 106 and the NFC 202, but the medium power 401 and the low power 400 do not affect the quality of the NFC communication. It shall be.

The power receiving device 200 according to the present embodiment stops sending charging power to the power transmitting device 100 when NFC communication that may be affected by wireless power transmission is started or is likely to be started. Send a notification that you should do it. Then, the power transmission device 100 reduces the electric power to be transmitted (for example, to the electric power of medium power or less) accordingly. This prevents electromagnetic waves (for example, harmonics) related to wireless power transmission from interfering with NFC communication.

(Processing flow)
Subsequently, the flow of processing executed in this system will be described with reference to FIGS. 5 and 6. FIG. 5 is a flowchart showing a flow of processing executed by the power receiving unit 205 and the communication unit 204 of the power receiving device 200, and FIG. 6 shows a processing flow executed between the power transmitting device 100 and the power receiving device 200. It is a sequence diagram. In the following, for the sake of simplicity, the power transmission unit 103 and the communication unit 104 of the power transmission device 100 are collectively referred to as a power transmitter, and the power reception unit 205 and the communication unit 204 are collectively referred to as a power receiver.

(Flow of processing of power receiver)
First, the flow of processing executed by the power receiving device 200 in the power receiving device 200 will be described with reference to FIG.

Here, the process shown in FIG. 5 can be started when the power is turned on to the power receivers (power receiving unit 205 and communication unit 204) of the power receiving device 200. The process shown in FIG. 5 can be realized by the power receiver executing a program stored in a memory (not shown) inside the power receiving device 200. Further, some or all of the steps shown in the flowchart of FIG. 5 may be realized by hardware such as an ASIC (application specific integrated circuit).

In order to realize at least a part of the processing shown in FIG. 5 by hardware, for example, a dedicated circuit can be automatically generated on the FPGA from the program for realizing each step by using a predetermined compiler. .. FPGA is an acronym for Field Programmable Gate Array. Further, a Gate Array circuit may be formed in the same manner as the FPGA and realized as hardware.

When the power receiving device receives the medium power transmitted from the power transmission device in response to the power receiving device 200 entering the power transmission range of the power transmission device 100 (S501), the power receiving device subsequently receives a restriction instruction from the first control unit 201. It is determined whether or not (S502). Then, when the power receiver receives the restriction instruction from the first control unit 201 (YES in S502), the power receiver notifies the power transmission stop (NFC) of the power transmission stop (NFC) (S505), and ends the process. Here, the transmission suspension (NFC), as described above, requests the transmission suspension of charging power, and explicitly or implicitly indicates that the reason for the request is to protect NFC communication. Information.

On the other hand, when the power receiver has not received the restriction instruction from the first control unit 201 (NO in S502), the power receiver determines whether charging is completed (S503). Here, for example, it can be determined whether or not the charging is completed depending on whether or not the battery is fully charged, whether or not the remaining battery level exceeds a predetermined value, whether or not a predetermined amount of electric energy is received, and the like. .. Then, when the power receiver does not finish charging (NO in S503), it receives the charging power (S504) and returns the process to S502. Then, the power receiver continues to receive the charging power while monitoring whether or not the restriction instruction is issued from the first control unit 201. Then, when the charging is completed (YES in S503), the power receiver transmits a power transmission stop notification indicating that the power transmission is requested to be stopped, for example, by control communication (S506). In addition, the power transmission stop notification here includes information indicating the reason for the power transmission stop, such as that the battery is fully charged, that the remaining battery level exceeds a predetermined value, and that the reception of a predetermined amount of power is completed. May be included.

After transmitting the power transmission stop (NFC) for the protection of NFC communication, the power receiver receives a restriction release instruction from the first control unit 201, for example, in response to the end of NFC communication. The first control unit 201 may explicitly issue a restriction release instruction. For example, the restriction release instruction is periodically issued during NFC communication, and the issuance is stopped after the communication is completed. You may implicitly notify the restriction release instruction by such means. In any case, after recognizing the restriction release instruction, the power receiver waits for the medium power to arrive from the transmitter, and processes from S502 again according to the fact that the medium power is received (S501). To execute.

Here, when the power transmission device 100 receives the notification of the power transmission stop (NFC), it is assumed that the power transmission of the charging power or the medium power is stopped. At this time, the transmitter continues to transmit, for example, a small amount of electric power on a regular basis. In addition, for example, when there is no change in the object detection result due to low power after the elapse of a predetermined period, that is, when there is no change in the situation where it can be determined that the power receiving device 200 exists in the vicinity, the power transmitter is again medium power. Can be sent. At that time, the power receiver can execute the processing after S502 according to the fact that the retransmitted medium power is received (S501). That is, if the NFC communication is ongoing and the restriction instruction is not released, the power transmission transmits the power transmission stop (NFC) to the transmitter again, and if the restriction instruction is released, the power transmission receives the restriction instruction again. The charging power is received until it is determined that charging is completed.

When the power transmission receives the notification of the power transmission stop (NFC), the power transmission of the charging power is stopped, but the medium power may be continuously transmitted. According to this, control communication between the transmitter and the receiver can be executed by transmitting medium power that does not affect the quality of NFC communication. For example, the power transmitter can receive a predetermined signal from the power receiver at a predetermined time interval using the transmitted medium power, thereby determining whether or not the power receiver is within the transmittable range. Further, in this case, when the power receiver receives the restriction release instruction from the first control unit 201, the power receiver can notify the transmitter of the restriction release by control communication. In this case, the power receiver determines whether or not the restriction release instruction has been received after the process of S505 in FIG. 5, returns the process to S501 if not received, and notifies the restriction release if it receives it. Can be transmitted to the transmitter and then the process can be transferred to S503 or S504. In addition, the power receiver requests a power increase / decrease to request the power transmitter to increase or decrease the transmitted power in a state where the charging power can be received (that is, when NFC communication is not performed). Can be sent.

(System processing flow)
Subsequently, the flow of processing executed by the NFC 106 and the power transmission device of the power transmission device 100 and the first control unit 201, NFC 202 and the power reception device of the power reception device 200 according to the present embodiment will be described with reference to FIG. Here, it is assumed that the NFC reader / writer (NFC106) executes a higher-level application using the NFC tag (NFC202) and the NFC as the communication partner. For that purpose, the reader / writer transmits information about the register to be read / written (hereinafter referred to as "command") among the registers existing in the NFC tag, at least by superimposing an electromagnetic wave on the power that the NFC tag can operate. .. The electromagnetic wave including the electric power and the command is referred to as "polling" in the present embodiment. When the NFC tag receives the poll, it activates the first control unit 201 to understand the command, and transmits a response which is a response to the command.

In the processing example of FIG. 6, first, the NFC 106 transmits polling via the NFC antenna (S601). Then, the NFC 202 receives the poll, demodulates the command correctly, and uses the understanding of the communication start intention indicated by the NFC 106 as a trigger to indicate to the first control unit 201 that the NFC communication is started. Is notified (S602). Then, the NFC 202 sends a response to the NFC 106 in response to the polling (S603).

Upon receiving the notification of the start of communication in S602, the first control unit 201 notifies the power receiver of a restriction instruction indicating that the transmitted power should be restricted in order to protect the NFC communication (S604). This restriction instruction may be notified by turning on / off (increasing / decreasing the voltage) the signal line connecting the power receiving unit 205 and the first control unit 201.

Here, in the power transmission device 100, the power transmission device periodically transmits a small amount of electric power, and the power receiving device 200 is in a state of being able to receive the transmitted power (that is, the power receiving device 200 transmits the power transmission of the power transmission device 100. It is assumed that it is within the possible range) (S605). In this case, the power transmission determines that an object exists within the power transmission range, and transmits medium power (S606).

When the power receiver receives the medium power, it determines whether or not the restriction instruction is received from the first control unit 201. In this case, since the power receiver has received the restriction instruction in S604, the power receiver is notified of the power transmission stop (NFC) by control communication (S607). Here, the power transmission stop (NFC) is information indicating that the power transmission stop of the charging power is requested and the reason for the request is to protect the NFC communication as described above. Then, the transmitter does not transmit the charging power in response to the request for this transmission stop (NFC). At this time, the transmitter may continue to transmit the medium power, or may stop transmitting the medium power. In addition, here, it is assumed that the transmitter does not transmit medium power.

Here, when the NFC 202 determines that the NFC communication has ended, it notifies the first control unit 201 of information indicating the end of the NFC communication (S608). Here, the NFC 202 can determine that the NFC communication has ended, for example, when it determines that the reading / writing to the register specified by the command in the polling and the transmission of the response have ended. Upon receiving the notification of the end of communication, the first control unit 201 transmits the restriction release to the power receiver as a notification for releasing the state in which the transmitted power is restricted in order to protect the NFC communication (S609).

Subsequently, the transmitter transmits low power and medium power as in S605 and S606 (S610, S611). Then, when the power receiver receives the medium power, the restriction instruction is released at this point. Therefore, the power receiver subsequently determines whether to end charging by checking the remaining battery level, etc., and if not ending charging, sends a device ID indicating the identification information of the power receiver itself to the transmitter. (S612). Then, the power receiver transmits the capacity information to the transmitter, including, for example, the maximum value of the electric power supplied to the charging unit 207 (S613). Then, after receiving the capacity information, the transmitter sends charging power to the receiver (S614). Then, when the power receiver receives the charging power, it supplies power to the battery 209 via the charging unit 207, monitors whether the power is suitable for charging, and requests power transmission with the appropriate power. The power increase / decrease request is transmitted to the transmitter (S615). The power receiver may transmit this power increase / decrease request as necessary, that is, not only once but also twice or more.

Here, it is assumed that the NFC 106 transmits polling while the transmitter is transmitting the charging power (S616). Upon receiving the poll, the NFC 202 notifies the first control unit 201 of the start of communication (S617), similarly to S602. Upon receiving the notification of the start of NFC communication, the first control unit 201 issues a restriction instruction to the power receiver (S619). Further, the NFC 202 transmits a response to polling to the NFC 106 (S618).

Here, at the timing when the poll of S601 is transmitted, the charging power is not transmitted from the transmitter, so that the NFC 202 can correctly demodulate the command in the poll. However, at the timing when the polling of S616 is transmitted, the charging power is transmitted during power transmission. Therefore, the waveform of the command in the polling may be distorted by the noise component included in the charging power, and the NFC 202 may not be able to demodulate the command correctly. In this way, if the demodulation of the command in polling fails, the NFC202 cannot accurately determine whether the communication has started. However, as described above, the operating frequency of the electric power transmitted by the power transmission is several hundred kHz, and the operating frequency of the NFC is 13.56 MHz. Since different operating frequencies are used in this way, it is unlikely that the NFC 202 of the power receiving device 200 and the first control unit 201 are activated by the electric power transmitted by the power transmitter. That is, the NFC 202 can determine that the polling has been received, that is, the NFC communication has been started by activating the NFC 202 and the first control unit 201. In summary, the NFC 202 can determine that NFC communication has started not only when the NFC 202 can demodulate the command correctly, but also when the NFC 202 and the first control unit 201 are activated.

Returning to FIG. 6, when the power receiver receives the restriction instruction, it transmits a power transmission stop (NFC) to the power transmission (S620). Since the power transmission is requested to stop the power transmission, the power transmission of the charging power is stopped, and a small amount of power is transmitted at a predetermined time interval (S621). As described above, if the result of object detection by transmitting a small amount of electric power does not change, it can be determined that the power receiver continues to exist in the transmittable range. When the period elapses, medium power can be transmitted (S622). However, since the power receiver has not received the restriction release from the first control unit 201 at this point, the power transmission stop (NFC) can be transmitted again to the power transmission in response to the reception of the medium power. (S623). After that, when the NFC 202 notifies the first control unit 201 to that effect when the NFC communication is terminated (S624), the first control unit 201 notifies the power receiver of the release of the restriction (S625). The subsequent processing of S626 to S630 is the same as the processing of S610 to S614, and thus the description thereof will be omitted.

After that, the power receiver transmits a notification for requesting the stop of power transmission to the power transmission when the charging is completed due to the battery being fully charged or the like (S631). The power transmission stop notified by the power receiver may include information indicating the reason for the power transmission stop. For example, in this example, the power receiver transmits information indicating that the full charge is the reason for requesting the power transmission stop, including the information in the message. Upon receiving the power transmission stop request, the transmitter ends the transmission of charging power (and medium power), and then resumes the periodic transmission of low power again (S632).

As described above, the power receiving device 200 according to the present embodiment notifies the power transmission device 100 of the power transmission stop (NFC) of the charging power when the NFC communication is started or is likely to be started. To do. The power receiving device 200 can determine that NFC communication has been started or may be started when the NFC 202 and the first control unit 201 are started. This makes it possible to prevent the power transmission device 100 from transmitting the charging power and prevent the electromagnetic waves of wireless power transmission from interfering with the NFC communication.

In the example of FIG. 6, when the power transmission receives the power transmission stop (NFC), not only the charging power but also the power transmission at the medium power is stopped. In this case, the operation of the power receiver can be reset because the power supply to the power receiver is interrupted in response to the suspension of the power transmission for charging and the medium power. In this case, the transmitter and the receiver will execute the sequence of wireless power transmission (for example, the processing of S628 and S629) when resuming the transmission and reception of the charging power. On the other hand, as described above, the transmitter may stop the transmission of the charging power but maintain the transmission of the medium power even when the transmission stop (NFC) is received. According to this, since power is continuously supplied to the power receiver, the power receiver can maintain a predetermined communication such as survival confirmation with the power transmitter. Therefore, the power receiver can immediately transmit a power increase request to the power transmitter in response to receiving the communication cancellation from the first control unit 201, for example, in S625. As a result, the power receiver can receive the charging power at an early stage. In addition, the power receiver does not transmit the power transmission stop (NFC) to the power transmission, but requests that the power transmitted by the power transmission be at the same level as the medium power by the power increase / decrease request such as S614. You may.

Further, in the present embodiment, the NFC 202 determines the start and end of the NFC communication, but this determination may be performed by the power receiver. For example, the power receiver can observe the power supply voltage (not shown) of the NFC 202 or the first control unit 201 when it is started by receiving the medium power. Then, when the power receiver detects a voltage value at which the NFC 202 or the first control unit 201 is activated, a predetermined process (that is, a restriction instruction in the above example) is performed according to the determination that the communication is started. (Processing when received) can be executed. Further, the start and end of NFC communication may be determined by detecting a minute signal of NFC that can be detected by the power receiving antenna 203 and the power receiving unit 205. Further, the end of NFC communication may be determined by, for example, a timer (not shown) inside the power receiving device 200. For example, as a timer setting value, a time is set during which the operation from the start of receiving the poll to the end of the transmission of the response can be performed for at least one cycle or more. As a result, the power receiving device 200 can determine that the NFC communication has ended at the expiration time of the timer by starting the timer in response to the determination that the reception of the poll has started.

The power transmission method of the wireless power transmission system according to the present embodiment is not particularly limited. For example, a magnetic field resonance method may be used in which power is transmitted by coupling of the magnetic field between the resonator (resonant element) of the power transmitting device 100 and the resonator (resonant element) of the power receiving device 200 by resonance (resonance). Further, an electromagnetic induction method, an electric field resonance method, a microwave method, a power transmission method using a laser or the like may be used.

Further, in the above description, the processing when the communication not related to the wireless power transmission is affected in the transmittable range of the wireless power transmission in the power transmission device 100 has been described. Here, NFC communication is an example of communication affected by wireless power transmission, and other communication methods may be used. For example, Bluetooth (registered trademark) Low Energy (BLE) standard, Wi-Fi (registered trademark), Zigbee (registered trademark), GPS may be used. The wireless communication that can be affected by wireless power transmission is not limited to the communication between the power transmitting device 100 and the power receiving device 200. That is, the communication performed around the power transmitting device 100 and the power receiving device 200 can also be affected by the wireless power transmission. Therefore, when the power receiving device 200 detects the communication performed in the vicinity, the power receiving device 200 can transmit a notification to the power transmission device 100 indicating that the power transmitted by the wireless power transmission should be limited. For example, the power receiving device 200 may notify the power transmission device 100 that the power transmitted by wireless power transmission should be limited when NFC communication is performed between the power transmission device 100 and another device different from the power transmission device 100.

Further, the control communication of the communication unit 104 or the communication unit 204 may be so-called in-band communication performed by superimposing the power transmitted from the power transmission antenna 105, but is not limited to this. That is, the control communication may be out-band communication, or may be performed according to the Bluetooth Low Energy (registered trademark) standard, Wi-Fi (registered trademark), Zigbee, or the like.

Further, the control communication of the communication unit 104 or the communication unit 204 may be so-called in-band communication performed by superimposing the power transmitted from the power transmission antenna 105, but is not limited to this. That is, the control communication may be out-band communication, or may be performed according to the Bluetooth Low Energy (registered trademark) standard, Wi-Fi (registered trademark), Zigbee, or the like.

Further, the power transmitting device 100 and the power receiving device 200 may be, for example, an image input device such as an image pickup device (camera, video camera, etc.) or a scanner, or an image output device such as a printer, a copier, or a projector. May be good. Further, these devices may be storage devices such as a hard disk device or a memory device, or may be an information processing device such as a personal computer (PC) or a smartphone.

<< Other Embodiments >>
The present invention is also realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiment is supplied to the system or device via a network or various storage media, and the computer (or CPU, MPU, etc.) of the system or device reads the program. This is the process to be executed.

100; power transmission device, 101: control unit, 103: power transmission unit, 104: communication unit, 106: NFC, 200: power receiving device, 201: first control unit, 202: NFC, 204: communication unit, 205: power receiving unit, 206: Second control unit

Claims (9)

A means of receiving power wirelessly from a power transmission device,
Using the first antenna, a first communication means for controlling the power supplied by the power receiving means to the load from the power transmission device is used, and a second antenna different from the first antenna is used. A communication means having a second communication means for performing communication different from the communication for control of receiving the electric power supplied to the load from the power transmission device, and
A notification for limiting the transmission of the power supplied to the load is transmitted to the power transmission device based on a communication different from the communication for controlling receiving the power supplied to the load from the power transmission device. It has a control means for controlling the communication means so as to perform the above.
The power receiving means and the first communication means are activated by the electric power received from the power transmission device.
The power receiving means uses a power smaller than the power supplied to the load while the second communication means performs communication different from the communication for controlling receiving the power supplied to the load from the power transmission device. A power receiving device, characterized in that it receives electric power capable of activating the power receiving means and the first communication means. The notification according to claim 1, wherein the notification includes information indicating that the communication means performs communication different from the communication for control of receiving the electric power supplied to the load from the power transmission device. Power receiving device. The control means is performing communication different from the communication for controlling receiving the electric power supplied to the load from the power transmission device, or for controlling receiving the electric power supplied to the load from the power transmission device. The power receiving device according to claim 1 or 2, wherein the communication means is controlled so as to transmit the notification based on the possibility of performing communication different from the communication of the above. The communication different from the communication for controlling receiving the electric power supplied to the load from the power transmission device is for executing an application not related to the communication for controlling receiving the electric power supplied to the load from the power transmission device. The power receiving device according to any one of claims 1 to 3, wherein the power receiving device includes the communication of the above. Before Symbol receiving means, wherein prior to receiving the power supplied to the load, according to any one of claims 1 4, wherein the benzalkonium be receiving a smaller power than the power supplied to the load Power receiving device. Wherein, according to the notification of the order to limit the transmission of power supplied to the load, characterized by a Turkey be transmitted to the power transmitting device before receiving the power supplied to the load from the power transmitting device Item 2. The power receiving device according to any one of Items 1 to 5 . The power receiving device according to any one of claims 1 to 6 , wherein the first communication means and the second communication means communicate using different frequencies. A means of receiving power wirelessly from a power transmission device,
Using the first antenna, a first communication means for controlling the power supplied by the power receiving means to the load from the power transmission device is used, and a second antenna different from the first antenna is used. A communication means having a second communication means for performing communication different from the communication for control of receiving the electric power supplied to the load from the power transmission device , and
It is a control method of a power receiving device having
The power receiving process of receiving power by the power receiving means and
A communication process for communicating by the communication means and
In the communication process, the power to be supplied before Kimake load based on said different communication from the communication for control to receive power from the power transmitting device is carried out, thereby limiting the transmission of power supplied to the load a controlling process of controlling the communication means such notification for are sent before Symbol power transmission device,
Have,
The power receiving means and the first communication means are activated by the electric power received from the power transmission device in the power receiving process.
In the power receiving step, the power supplied to the load is smaller than the power supplied to the load while the second communication means performs communication different from the communication for controlling receiving the power supplied to the load from the power transmission device. A control method, characterized in that electric power capable of activating the power receiving means and the first communication means is received . A program for causing a computer to function as the power receiving device according to any one of claims 1 to 7 .

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