JP2020188547A - Power receiving device and control method thereof, and wireless power transmission system - Google Patents

Abstract

To appropriately control a timing of executing a transmission stop request.SOLUTION: In a power receiving device (100) that receives power wirelessly from a power transmission device (200), an authentication correspondence determination unit (108) and an authentication status determination unit (109) determine authentication status of whether the power transmission device supports a predetermined certification (WPT certification), and determines whether a predetermined authentication has been completed with the power transmission device. A determination unit (110) determines a timing of making a request to stop the power transmission by the power transmission device on the basis of the determined authentication status. A control unit (101) requests the power transmission device to stop power transmission at a determined timing.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wireless power transmission system, a power receiving device, and a control method thereof.

In recent years, technological development of wireless power transmission systems has been widely carried out. Patent Document 1 discloses a power transmission device and a power receiving device conforming to a standard established by a standardization body for a non-contact charging standard (Wireless Power Consortium (WPC)). Further, Patent Document 2 discloses a device authentication method between a non-contact charging power transmitting device and a power receiving device. On the other hand, in the WPC standard, wireless power transmission by the power transmission device is stopped by requesting the power transmission device to stop power transmission from the power receiving device. The power receiving device requests to stop power transmission according to the state of the device, such as the state of charge of the battery.

Japanese Unexamined Patent Publication No. 2016-007116 Japanese Unexamined Patent Publication No. 2010-104097

When performing device certification as in Patent Document 2, it is conceivable that information on certification is retained in both the power receiving device and the power transmission device, and based on the retained information, the authentication from the next time onward should be simplified. Can be considered.

When a request to stop power transmission is issued and power transmission is stopped, the power receiving device and the power transmitting device cannot perform device certification. For example, if a power receiving device in which the battery is fully charged is placed on the power transmission device, the power receiving device requests the power transmission device to stop power transmission immediately after the start, and device authentication between the two devices is not performed. Therefore, even if the power receiving device is mounted on the power transmission device in the expectation that the device authentication will be performed, the device authentication may not be executed.

The present invention provides a technique for appropriately controlling the timing of executing a power transmission stop request.

The power receiving device according to one aspect of the present invention has the following configurations. That is,
It is a power receiving device that receives power wirelessly from the power transmission device.
A determination means for determining an authentication state including whether or not the power transmission device supports a predetermined authentication and whether or not the predetermined authentication has been completed with the power transmission device.
The power transmission device is provided with a requesting means for requesting a power transmission stop.
The requesting means determines the timing of requesting the power transmission stop based on the authentication state determined by the determining means.

According to the present invention, the timing of executing the power transmission stop request is appropriately controlled.

(A) is a diagram showing a configuration of a wireless power transmission system according to an embodiment, and (b) is a block diagram showing a configuration example of a power receiving device according to an embodiment. The block diagram which shows the structural example of the power transmission apparatus which concerns on embodiment. The figure explaining the operation of the power receiving device and the power transmission device in the fully charged state in the state where the authentication is not completed. The figure explaining the operation of the power receiving device and the power transmission device in the fully charged state in the authentication completion state. The flowchart explaining the operation of the power receiving device which concerns on embodiment. A flowchart illustrating the operation of the power transmission device according to the embodiment.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. The following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiment, not all of the plurality of features are essential to the invention, and the plurality of features may be arbitrarily combined. Further, in the attached drawings, the same or similar configurations are designated by the same reference numbers, and duplicate description is omitted.

FIG. 1A is a diagram showing a configuration example of a wireless power transmission system according to an embodiment. The wireless power transmission system has a power receiving device 100 and a power transmitting device 200, and by arranging the power receiving device 100 in the vicinity of the power transmitting device 200, power is transmitted from the power transmitting device 200 to the power receiving device 100. As a wireless power transmission method, a magnetic field coupling method, an electric field coupling method, and the like are known, and any of them can be applied to the non-electric power transmission system of the present embodiment. In the embodiment, a configuration in which wireless power transmission is performed by a magnetic field coupling method using a coil will be described. When power is supplied from the AC adapter 300 to the power transmission device 200, the power transmission device 200 starts wireless power transmission to the power reception device 100.

FIG. 1B is a block diagram showing a configuration example of the power receiving device 100 according to the present embodiment. The power receiving device 100 of the present embodiment conforms to the standard established by the WPC (Wireless Power Consortium), and includes the functions described in the WPC standard v1.2.3. Hereinafter, the power receiving device 100 is also referred to as RX. Further, FIG. 2 is a block diagram showing a configuration example of the power transmission device 200 according to the present embodiment. The power transmission device 200 also conforms to the standard established by WPC, and includes the functions described in WPC standard v1.2.3. Hereinafter, the power transmission device 200 is also referred to as TX. The TX has the ability to supply enough power to output up to 15 watts of power to the charging unit for the RX that complies with the WPC standard.

In RX, the control unit 101 has, for example, a processor (CPU) and controls the entire RX. The power receiving unit 102 receives an AC voltage (alternating current) from the TX power transmission coil 205 via the power receiving coil 104. The power receiving unit 102 converts the received AC voltage (AC current) into a DC voltage (DC current) and supplies it to the control unit 101, the charging unit 105, and the like.

The communication unit 103 performs wireless communication with the communication unit 204 of the TX for controlling non-contact charging based on the WPC standard. Here, for wireless communication, a method of load-modulating the electromagnetic wave received by the power receiving coil 104 is used. Hereinafter, communication by this method is referred to as first communication. However, the wireless communication by the communication unit 103 is not limited to the first communication, and for example, a communication method using a frequency different from the frequency for power transmission may be used. Hereinafter, communication by this method is referred to as second communication. The communication unit 103 can perform the second communication using, for example, NFC (Near Field Communication), RFID (radio frequency identification identifier), wireless LAN (Wi-Fi), Bluetooth (registered trademark), or the like. The first communication is performed using the power receiving coil 104, and the second communication is performed using a communication antenna different from the power receiving coil. The second communication has a higher communication speed and a longer communication distance than the first communication.

The charging unit 105 charges the battery 106 by using the DC voltage and the DC current supplied from the power receiving unit 102. The authentication unit 107 has a function of performing WPT authentication between the TX and RX by communicating with the TX via the communication unit 103. WPT is Wireless Power Transfer. The authentication correspondence determination unit 108 determines whether or not each of the TX and RX is compatible with WPT authentication based on the information notified from the TX.

The authentication status determination unit 109 determines whether or not the TX and RX have completed WPT authentication based on the information notified from the TX. In WPT certification, TX and RX mutually certify the validity of each other, and after successful certification, the certification becomes valid for a certain period of time. In the present embodiment, the "WPT authentication completed" state means a state in which WPT authentication is valid. On the other hand, if the WPT authentication fails, or if the WPT authentication is revoked and the authentication status is not valid even after the WPT authentication is successful, the WPT authentication is not completed.

The authentication status determination unit 109 stores the TX identification information in association with whether or not WPT authentication is completed. Further, when the authentication status determination unit 109 receives an inquiry about the authentication status from the control unit 101 together with the TX identification information, the authentication status determination unit 109 outputs the stored authentication status to the control unit 101. The authentication status determination unit 109 associates and stores the remaining period of the period in which the authentication status is valid, and when the control unit 101 inquires about the authentication status, notifies the remaining period together with the authentication status. You may. Alternatively, the authentication status determination unit 109 notifies the control unit 101 that the WPT authentication has not been completed when the remaining period is less than the threshold value at the time when the authentication status is inquired. You may do so.

The determination unit 110 determines the timing at which the notification packet (transmission stop request) for stopping the power transmission from the TX is transmitted to the TX. This notification packet is, for example, an End Power Transfer packet (hereinafter referred to as an EPT packet) in the WPC standard. Of course, other packets indicating that the TX should stop power transmission may be used, or a predetermined signal may be used.

The determination unit 110 is based on the authentication status determined by the authentication correspondence determination unit 108 and the authentication status determination unit 109 (whether the power transmission device supports WPT authentication or WPT authentication with the power transmission device is completed). , Determine the request timing for power transmission stop. For example, in the determination unit 110, when the TX supports WPT authentication and the WPT authentication between the TX and RX is not completed, the power transmission stop request timing (EPT packet transmission timing) is WPT authentication. Decide to be after the completion of. Further, when TX does not support WPT authentication, or when WPT authentication has already been completed, the determination unit 110 does not limit the timing of the power transmission stop request (EPT packet transmission timing). For example, if it is detected that the battery 106 is fully charged, the determination unit 110 determines the request timing for stopping the power transmission so as to immediately stop the power transmission by the TX. Alternatively, if it is detected that the battery 106 is not fully charged, the TX power transmission is stopped according to the fact that the battery 106 is fully charged (the remaining amount of the battery 106 exceeds a predetermined amount). To determine the request timing for power transmission stop.

The EPT packet transmission timing may be other than the above. For example, if the RX is equipped with a temperature measuring unit (not shown) and the temperature of the RX is detected to be higher than the threshold value, the determination unit 110 immediately, that is, unconditionally, transmits an EPT packet. The transmission timing may be determined. When the RX temperature exceeds the threshold, the EPT packet is transmitted regardless of whether WPT authentication is completed or not. By defining the transmission timing of the ETP packet in this way, it is possible to suppress the temperature rise of the RX and improve the convenience of the user.

Further, the TX may finally determine the transmission timing of the EPT packet in the RX. In this case, RX notifies TX of the scheduled transmission timing of the EPT packet and the reason why the transmission timing is scheduled. The TX determines the transmission timing of the EPT packet based on the scheduled transmission timing and the reason received from the RX, and notifies the RX of this. The RX determines the transmission timing received from the TX (transmission timing specified by the TX) as the EPT transmission timing. For example, the determination unit 110 sets the transmission timing of the EPT packet when the WPT authentication is completed (or the time when the WPT authentication is expected) because the power transmission device supports the WPT authentication but the WPT authentication is not completed. Suppose you have a plan. The RX notifies the TX of the scheduled transmission timing determined by the determination unit 110 and the reason thereof. The TX interprets the transmission timing and the reason received from the RX, and notifies the RX of the specification of the timing at which the RX should transmit the EPT packet. The TX notifies RX that if there is no inconvenience in the notified transmission timing, it acknowledges the transmission timing, and if there is an inconvenience in the notified timing, a different timing is specified in RX. In this way, since the transmission timing of the EPT packet by RX is determined by the cooperation of TX and RX, it is possible to determine whether or not to execute WPT authentication according to the state of TX, and the convenience of the user is enhanced. Can be done.

The memory 111 stores a program executed by the processor included in the control unit 101, and also provides a work area used by the processor. The requesting unit 112 requests the TX to stop power transmission. The memory 111 also stores the state of each element and the entire state of the RX and the wireless power transmission system for non-contact charging shown in FIG. 1A. The request unit 112 executes the request for stopping the power transmission at the timing determined by the determination unit 110. All or part of the functions of the authentication unit 107, the authentication correspondence determination unit 108, the authentication status determination unit 109, the determination unit 110, and the request unit 112 are realized by the control unit 101 (by the processor executing the program). You may.

In the TX configuration shown in FIG. 2, the control unit 201 has, for example, a processor (CPU) and controls the entire TX. The power supply unit 202 receives the operating power supply of the TX from the AC adapter 300, and supplies at least the power supply for operating the control unit 201 and the power transmission unit 203. The power transmission unit 203 generates an alternating voltage (alternating current) to be transmitted to the RX via the power transmission coil 205. For example, the power transmission unit 203 converts the DC voltage supplied by the power supply unit 202 into an AC voltage by using a switching circuit having a half-bridge or full-bridge configuration using FETs. Further, the power transmission unit 203 includes a gate driver that controls ON / OFF of the FET.

The communication unit 204 performs wireless communication with the communication unit 103 of the RX for controlling wireless power transmission based on the WPC standard. In the present embodiment, as the wireless communication executed by the communication unit 204, the first communication is used as described above. In the first communication, the communication is superimposed on the wireless power by modulating the AC voltage or AC current generated by the power transmission unit 203. However, the communication of the communication unit 204 is not limited to the first communication, and may be a second communication using a frequency different from the power transmission frequency used by the power transmission unit 203. As the second communication, for example, NFC, RFID, wireless LAN (Wi-Fi), Bluetooth (registered trademark), or the like can be used.

The authentication correspondence notification unit 206 notifies the RX via the communication unit 204 whether or not the TX supports WPT authentication. The authentication status notification unit 207 receives an inquiry about the authentication status from the RX, and notifies the RX via the communication unit 204 whether or not the WPT authentication between the RX and the TX has been completed, together with the identification information of the TX. Notice. The authentication status notification unit 207 stores the RX identification information in association with the information indicating whether or not the RX and WPT authentication have been completed. The authentication unit 208 has a function of performing WPT authentication between the TX and the RX by communicating with the RX via the communication unit 204.

The memory 209 stores a program executed by the processor included in the control unit 201, and also provides a work area used by the processor. The memory 209 also stores the state of each element and the entire state of the TX and the wireless power transmission system for non-contact charging shown in FIG. 1A. Note that all or part of the functions of the authentication unit 208, the authentication correspondence notification unit 206, and the authentication status notification unit 207 may be realized by the control unit 201 (by executing a program by the processor).

It should be noted that the fact that TX or RX is compatible with the WPC standard including WPT certification is expressed as being compatible with the WPC standard version A. Here, WPC standard version A is a standard that succeeds WPC v1.2.3, and at least a WPT authentication function is added. When RX and TX correspond to WPC standard version A, for example, RX and TX can exchange a predetermined power (15 watts) for high-speed charging. Even though at least one of RX and TX does not support WPC standard version A, if you exchange at 15 watts, it will generate excessive heat and there is a risk of ignition and user burns, so device authentication is required. ..

RX and TX check each other to see if they support WPC standard version A, but if a malicious RX or TX is provided even though they do not actually support it, checking the version alone is a risk. Cannot be avoided. Therefore, RX and TX perform WPT authentication as device authentication, and high-speed charging can be performed only when both RX and TX succeed in WPT authentication. This is because WPT certification confirms that the declaration of WPC standard version A by both the power transmitting device and the power receiving device is reliable.

That is, when RX and TX succeed in WPT authentication, there is no risk of excessive heat generation even if the power receiving unit 102 of RX supplies a predetermined power (15 watts) to the load (charging unit 105 in this example). Can be judged. In addition, if WPT authentication is not successful, there is a possibility of such a risk, so the power transmitted wirelessly is limited to power smaller than a predetermined power (5 watts in this example). Fast charging with a power supply of 15 watts is desired to shorten the charging time, but this can only be done if the RX and TX have successfully WPT certified.

Generally, in order for RX and TX to carry out the WPT certification process, RX needs to continue to receive power from TX. For example, in the first communication, the device authentication protocol communication is performed superimposing on the power transmission, and when the power transmission is stopped, the device authentication protocol communication cannot be performed. Further, when the authentication process by the control unit 101 using the authentication unit 107 operates by receiving the power supply from the power receiving unit 102, the authentication process cannot operate when the transmitted power is stopped. The case of the first communication has been described above, but even in the case of the second communication, in the configuration in which the authentication process by the control unit 201 and the authentication unit 208 operates with the transmitted power, the authentication process is executed by stopping the power transmission. Can not be done.

When the battery 106 is fully charged or exceeds a predetermined charge amount due to the power received from the TX, the RX transmits a packet (EPT) for requesting the stop of power transmission to the TX. Upon receiving the EPT packet, the TX stops the radio power transmission to the RX. Therefore, if the RX is activated when the battery 106 is fully charged or exceeds a predetermined charge amount, the RX sends an EPT packet requesting the stop of power transmission to the TX before activating the WPT authentication. As a result, the power transmission from the TX is stopped, and the RX cannot activate the WPT authentication.

If the WPT authentication between RX and TX is not completed, the WPT authentication, which takes several minutes, will be executed at the next charging opportunity. In that case, the transmission power cannot be increased to 15 watts for high-speed charging until the WPT certification is completed, and it is necessary to continue the power supply with the transmission power of 5 watts. As a result, it takes time to charge the battery 106.

Next, the operation of RX and TX according to the present embodiment that solves the above problems will be described. FIG. 3 is a diagram illustrating the operation of RX and TX when RX is started in a fully charged state and an authentication incomplete state (a state in which WPT authentication is not completed) is detected according to the present embodiment.

First, when the power transmission unit 203 is activated, the TX starts an operation conforming to the WPC standard. Specifically, the selection phase starts, and the power transmission unit 203 transmits analog pings via the power transmission coil 205 (301). The Analog Ping is a signal of minute electric power for detecting an object existing in the vicinity of the power transmission coil 205. TX detects the voltage value or current value of the power transmission coil 205 when transmitting Analog Ping, and if the voltage falls below a certain threshold value or the current value exceeds a certain threshold value, it determines that an object exists and transitions to the Ping phase. To do.

In the Ping phase, the TX transmits the Digital Ping with more power than the Analog Ping (302). The magnitude of the power of the Digital Ping is sufficient for starting the RX control unit 101 existing in the vicinity of the power transmission coil 205. When the RX receives the Digital Ping via the power receiving coil 104, the RX activates the control unit 101 (303). When the RX control unit 101 is activated, the RX control unit 101 determines the remaining battery level of the battery 106 (304). Here, it is detected that the battery 106 is fully charged (the remaining battery level exceeds a predetermined value). When the determination of the remaining battery level is completed, the RX transmits a received voltage value notification to the TX (305), and transitions to the Identity & Configuration phase (I & C phase). Further, the TX transitions to the I & C phase when the received voltage notification is received from the RX.

In the I & C phase, the RX transmits an Identity Packet (ID Packet) to the TX (306). The ID Packet includes information elements capable of identifying the individual identification information of RX and the corresponding version of the WPC standard (v1.2.3 in this example).

Subsequently, Negotiation is performed between RX and TX (307). In Negotiation, RX first transmits a Configuration Packet to TX. The Configuration Packet of WPC standard v1.2.3 includes a Maximum Power Value, which is a specific value of the maximum power that the RX can supply to the load, and a bit indicating whether or not it has a Negotiation function. In this example, it is assumed that RX has a Negotiation function.

Further, in Negotiation, when RX supports WPT authentication, RX transmits a signal inquiring information indicating the WPT authentication status. This inquiry signal may be stored in the Configuration Packet and transmitted, or may be transmitted by another packet or signal. When the TX receives the ID Packet and the Configuration Packet, it determines whether the RX has a Negotiation function. Since RX has a Negotiation function, TX transmits an ACK to the Configuration Packet.

Further, when the TX receives a signal from the RX inquiring about the information indicating the WPT authentication status, the TX transmits the information indicating the WPT authentication status to the RX. The information indicating the WPT authentication status includes TX identification information, RX identification information, and information indicating whether or not WPT authentication is completed. The information indicating the WPT authentication status may include the remaining period during which WPT authentication is valid. In addition, the TX also transmits information indicating whether or not the TX supports WPT authentication to the RX in response to a signal from the RX inquiring about the information indicating the WPT authentication status. The information indicating the authentication status and the information indicating the correspondence to the WPT authentication may be transmitted by being included in the ACK for the Configuration Packet, or may be transmitted by another packet or signal. After transmitting the above signal to RX, TX transitions to Calibration Phase (309).

When the RX receives information indicating whether or not the TX supports WPT authentication and information indicating the WPT authentication status from the TX, the RX starts the authentication status determination process (308). The RX determines whether or not the WPT authentication has been completed based on the information indicating the WPT authentication status including the TX identification information received from the TX. In the example of FIG. 3, since the WPT authentication is not completed, the determination unit 110 determines the timing so that the power transmission stop request (transmission of the EPT) is executed after the completion of the WPT authentication. Therefore, RX shifts to the Calibration phase to perform WPT certification (309). Even if the WPT certification is completed, if it is necessary to recertify the WPT certification, such as when the remaining validity period of the WPT certification is shorter than the predetermined period, the RX will complete the WPT certification. It shifts to the Calibration phase as it is not.

In the calibration phase, the TX adjusts the power transmitted to the RX by the TX based on the correlation between the value measured inside the TX and the value of the received power measured inside the RX. Since the calibration phase has little relevance to the present invention, detailed description thereof will be omitted.

When the calibration phase is completed, the TX and RX transition to the Power Transfer phase (PT phase) (310) Here, since WPT authentication is not completed, wireless power transmission is performed at 5 watts. TX and RX execute WPT authentication while performing wireless power transmission in the PT phase (311). When the RX detects that the WPT authentication is completed (312), it transmits an EPT packet as a notification packet for stopping power transmission (313). The timing of the power transmission stop request determined by the determination unit 110 in this way (when TX supports WPT authentication and WPT authentication between TX and RX is not completed, RX makes the power transmission stop request after completion. ) Is realized. The power transmission stop request is not limited to the EPT packet, and any signal may be used as long as the TX can recognize that the RX is requesting the TX to stop the power transmission.

FIG. 4 is a diagram illustrating the operation of RX and TX when RX is started in a fully charged state and an authentication completion state (a state in which WPT authentication is completed) is detected according to the present embodiment. In FIG. 4, the operation of Negotiation from the power transmission of Analog Ping (401-407) is the same as the operation of 301-307 of FIG. However, the TX provides information indicating that the TX supports WPT authentication and that the WPT authentication with the RX has been completed in response to receiving a signal inquiring about the WPT authentication status from the RX. For example, it is transmitted to RX using an ACK packet. Here, the information indicating the WPT authentication status may include the remaining period of the validity period of the WPT authentication.

When the RX receives a signal from the TX that includes information indicating whether the TX supports WPT authentication and information indicating the WPT authentication status by ACK or another packet or signal, the RX starts the authentication status determination process. (408). When the RX determines that the WPT authentication with the TX has been completed based on the information indicating the WPT authentication status including the TX identification information received from the TX, the RX transmits an EPT packet for stopping the power transmission (409). ). The notification packet for stopping the power transmission is not limited to the EPT packet, and it is sufficient that the TX can recognize that the RX has requested the TX to stop the power transmission. In this way, the operation of power transmission stop is realized at the timing determined by the determination unit 110 (the timing of requesting power transmission stop when the WPT authentication between TX and RX is completed).

The processing of the RX control unit 101 that realizes the above operation will be described with reference to the flowchart of FIG.

In S501, the RX (control unit 101) is activated by the power received by the wireless power transmission. In S502, the control unit 101 detects the charging state (remaining battery level) of the battery 106. In S503, the authentication correspondence determination unit 108 acquires information indicating whether or not the TX supports WPT authentication (hereinafter referred to as authentication correspondence information) from the ACK or other packet received from the TX. The ACK or other packet (signal) is received from the TX via the communication unit 103 in the negotiation (307 in FIG. 4). Then, in S504, the control unit 101 determines whether or not the TX supports WPT authentication. If it is determined that the TX is compatible with WPT authentication, the process proceeds to S505, and if it is determined that the TX is not compatible with WPT authentication, the process proceeds to S511.

In S505, the authentication status determination unit 109 acquires the authentication status information indicating the authentication status of WPT authentication in the TX from the ACK or another packet received from the TX by the control unit 101. Then, in S506, the authentication status determination unit 109 determines whether or not TX and RX have been WPT-authenticated based on the authentication status information. If it is determined in S506 that WPT authentication has been completed, the process proceeds to S507, and if it is determined that WPT authentication has not been completed, the process proceeds to S508.

In S507, the control unit 101 determines whether or not the battery 106 is fully charged (whether or not the remaining battery level exceeds a predetermined value) from the charged state of the battery 106 detected in S502. If it is determined that the battery is fully charged, the process proceeds to S513, and if it is determined that the battery is not fully charged, the process proceeds to S510. In S513, the requesting unit 112 transmits an EPT packet to the TX, stops the power transmission by the TX, and completes the power reception.

When the authentication status determination unit 109 determines in S506 that the WPT authentication is incomplete, in S508, the RX shifts to the PT phase and executes low power wireless power transmission. Then, in S509, the control unit 101 performs WPT authentication of TX and RX. In this case, low power (5 watts) wireless power transmission is continued. When the WPT authentication is completed, the process proceeds to S507. If it is determined in S507 that the battery 106 is not fully charged, the control unit 101 continues wireless power transmission in S510 to charge the battery 106. In S510, since WPT certification has been completed, wireless power transmission is performed at a high power of 15 watts. When the battery 106 is fully charged, the process proceeds to S513, and the request unit 112 transmits an EPT packet to the TX to stop the wireless power transmission.

On the other hand, when it is determined in S504 that TX does not support WPT authentication, in S511, the control unit 101 determines the remaining amount of the battery 106 from the charged state detected in S502. If it is determined in S511 that the battery is fully charged, the process proceeds to S513, and the requesting unit 112 transmits an EPT packet to the TX, stops power transmission by the TX, and completes power reception. If it is determined in S511 that the battery 106 is not fully charged, the process proceeds to S512, and the control unit 101 continues the wireless power transmission by the TX to charge the battery 106. In S512, since WPT certification has not been completed, wireless power transmission is performed with a low power of 5 watts. When the battery 106 is fully charged, the process proceeds to S513.

FIG. 6 is a flowchart illustrating the operation of the TX (power transmission device 200) according to the present embodiment, which realizes the operations described with reference to FIGS. 4 and 5.

In S601, TX uses Analog Ping and Digital Ping to detect the presence of RX in the vicinity of the coil. When RX is detected, the process proceeds to S602. In S602, the authentication correspondence notification unit 206 generates authentication correspondence information indicating whether or not the TX supports WPT authentication, notifies the RX via the power transmission coil 205, and outputs the authentication correspondence information to the control unit 201. In S603, the control unit 201 determines whether or not the TX supports WPT authentication based on the authentication correspondence information received from the authentication correspondence notification unit 206. Further, the control unit 201 determines whether or not the RX supports WPT authentication based on the information received from the RX. If it is determined that TX and RX support WPT authentication, the process proceeds to S604, and if at least one of TX and RX does not support WPT authentication, the process proceeds to S608.

In S604, the authentication status notification unit 207 notifies RX via the power transmission coil 205 of authentication status information indicating whether WPT authentication has been completed between RX and TX detected in S601, and controls the RX. Output to unit 201. Although the authentication correspondence information and the authentication status information are transmitted in separate steps, as described above, these information may be transmitted by one ACK packet.

In S605, the control unit 201 determines whether or not WPT authentication has been completed with the RX. If it is determined that the WPT authentication has been completed, the process proceeds to S607. On the other hand, if it is determined that the WPT authentication has not been completed, the process proceeds to S606. In S606, the control unit 201 shifts the TX to the PT phase, performs WPT authentication processing with the RX while transmitting low power wireless power to the RX. When the WPT authentication process is completed, the process proceeds to S607. In S607, the control unit 201 performs wireless power transmission to the RX. In S607, since the WPT certification has been completed, wireless power transmission at 15 watts, which is a high power, is performed. Further, when the TX or RX does not support WPT authentication, in S608, the control unit 201 executes low power (5 watts) wireless power transmission.

In S609, the control unit 201 stops the radio power transmission in response to receiving the EPT packet from the RX. When a power transmission stop request (EPT packet) is received from the power receiving device during the operation shown in FIG. 6, the control unit 201 immediately stops the wireless power transmission.

As described above, according to the power receiving device of the present embodiment, the power receiving device is wirelessly powered by the power transmission device based on the identification result of the state of the WPT authentication process (whether the authentication is supported or the authentication is completed). The timing to stop the transmission is decided. As a result, even when the battery of the power receiving device is in a fully charged state or in a state where the charge exceeds a predetermined amount, WPT authentication can be reliably activated and the authentication process can be completed. As described above, according to the power receiving device of the present embodiment, it is possible to appropriately control the timing of executing the power transmission stop request.

(Other Examples)
The present invention supplies a program that realizes one or more functions of the above-described embodiment to a system or device via a network or storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by the processing to be performed. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

The invention is not limited to the above embodiments, and various modifications and modifications can be made without departing from the spirit and scope of the invention. Therefore, a claim is attached to make the scope of the invention public.

100: Power receiving device, 101: Control unit, 102: Power receiving unit, 103: Communication unit, 104: Power receiving coil, 105: Charging unit, 106: Battery, 107: Authentication unit, 108: Authentication correspondence judgment unit, 109: Authentication status Judgment unit, 110: determination unit, 111: memory, 200: power receiving device, 300: AC adapter

Claims (15)

It is a power receiving device that receives power wirelessly from the power transmission device.
A determination means for determining an authentication state including whether or not the power transmission device supports a predetermined authentication and whether or not the predetermined authentication has been completed with the power transmission device.
The power transmission device is provided with a requesting means for requesting a power transmission stop.
The power receiving device is characterized in that the requesting means determines the timing of requesting the power transmission stop based on the authentication state determined by the determining means. The requesting means is a case where it is detected that the remaining amount of the battery of the power receiving device exceeds a predetermined amount, the determination means is in the authentication state, and the power transmission device corresponds to the predetermined authentication. The power receiving device according to claim 1, wherein when it is determined that the predetermined authentication is not completed, the power transmission stop is requested after the predetermined authentication is completed. The determination means is characterized in that even if the predetermined authentication is completed, it is determined that the predetermined authentication is incomplete when the remaining period of the valid period of the predetermined authentication is less than the threshold value. The power receiving device according to claim 2. When it is detected that the remaining amount of the battery of the power receiving device exceeds a predetermined amount, the requesting means responds to the determination that the determination means has completed the predetermined authentication as the authentication state. The power receiving device according to any one of claims 1 to 3, wherein the power transmission stop is requested. Information indicating whether or not the power transmission device complies with the predetermined authentication and whether or not the predetermined authentication has been completed between the power transmission device and the power receiving device is transmitted to the power transmission device. The power receiving device according to any one of claims 1 to 4, further comprising an acquisition means for acquiring by wireless communication. The power receiving device according to claim 5, wherein the wireless communication is a communication in which communication is superimposed on the power transmission by the wireless. The power receiving device according to claim 5, wherein the wireless communication is a communication using a frequency different from the frequency of power transmission by the wireless. The power receiving device according to claim 5, wherein the wireless communication is any one of NFC, RFID, wireless LAN, and Bluetooth. Further provided with a measuring means for measuring the temperature in the power receiving device,
Any one of claims 1 to 8, wherein the requesting means unconditionally requests the power transmission device to stop the power transmission when the temperature measured by the measuring means exceeds a predetermined value. The power receiving device described in the section. After the completion of the predetermined authentication, because the determination means determines that the power transmission device corresponds to the predetermined authentication and the predetermined authentication has not been completed with the power transmission device. A notification means for notifying the power transmission device that it is time to stop power transmission, and
The power receiving device according to claim 2 or 3, wherein the requesting means requests the power transmission stop at a timing designated by the power transmission device in response to the notification by the notification means. The power receiving device according to any one of claims 1 to 10, wherein the requesting means requests the power transmission stop by transmitting a signal indicating a power transmission stop request to the power transmission device. The requesting means according to any one of claims 1 to 10, wherein the requesting means requests the power transmission stop by transmitting an End Power Transfer packet defined by the standard of the Wireless Power Consortium to the power transmission device. The power receiving device described. It is a control method of the power receiving device that receives power wirelessly from the power transmitting device.
A determination step for determining an authentication state including whether or not the power transmission device supports a predetermined authentication and whether or not the predetermined authentication has been completed with the power transmission device.
It is provided with a requesting process for requesting the power transmission device to stop power transmission.
A method for controlling a power receiving device, characterized in that, in the requesting step, a timing for requesting the power transmission stop is determined based on the authentication state determined in the determination step. A power transmission device that transmits electricity wirelessly,
A power receiving device that receives power wirelessly from the power transmitting device and
Determines the authentication status including whether or not the power receiving device and the power transmitting device support a predetermined authentication, and whether or not the predetermined authentication is completed between the power receiving device and the power transmitting device. Judgment means and
A requesting means for requesting the power transmission device to stop power transmission from the power receiving device is provided.
The requesting means is a wireless power transmission system characterized in that a timing for requesting a stop of power transmission is determined based on the authentication state determined by the determining means. A program for causing a computer to function as each means of the power receiving device according to any one of claims 1 to 12.

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