WO2022255094A1 - 送電装置および受電装置 - Google Patents
送電装置および受電装置 Download PDFInfo
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- WO2022255094A1 WO2022255094A1 PCT/JP2022/020582 JP2022020582W WO2022255094A1 WO 2022255094 A1 WO2022255094 A1 WO 2022255094A1 JP 2022020582 W JP2022020582 W JP 2022020582W WO 2022255094 A1 WO2022255094 A1 WO 2022255094A1
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- existence probability
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- power transmission
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
- H02J50/60—Circuit arrangements or systems for wireless supply or distribution of electric power responsive to the presence of foreign objects, e.g. detection of living beings
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
- H02J50/10—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
- H02J50/10—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling
- H02J50/12—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling of the resonant type
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
- H02J50/80—Circuit arrangements or systems for wireless supply or distribution of electric power involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/00032—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries characterised by data exchange
- H02J7/00034—Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
Definitions
- the present disclosure relates to a power transmission device, a power reception device, a wireless power transmission system, a power transmission device control method, a power reception device control method, and a program.
- Patent Literature 1 discloses a power transmitting device and a power receiving device conforming to a standard (WPC standard) established by the Wireless Power Consortium (WPC), a standardization body for wireless charging standards.
- Patent Document 2 discloses a foreign object detection method in the WPC standard.
- a foreign object is an object different from the power receiving device.
- a power transmission device first calculates in advance the amount of power loss in a state where there is no foreign object between the power transmission device and the power reception device from the difference between the power transmitted by the power transmission device and the power received by the power reception device, and is the amount of power loss in the normal state (with no foreign matter). After that, the power transmitting device determines whether or not a foreign object exists based on the amount of power loss between the power transmitting device and the power receiving device calculated during subsequent power transmission.
- the above foreign object detection is performed by the power transmission device.
- the power transmitting device to appropriately transmit foreign object detection information including the existence probability of the foreign object to the power receiving device after performing the foreign object detection.
- An object of the present disclosure is to enable information based on the existence probability of an object different from that of the power receiving device to be appropriately transmitted from the power transmitting device to the power receiving device.
- the power transmitting device is a power transmitting device that wirelessly transmits power to a power receiving device, and includes obtaining means for obtaining a parameter used for determining the existence probability of an object different from the power receiving device, and based on the parameter obtained by the obtaining means. determining means for determining the existence probability of the object; and transmitting a signal including information for specifying the existence probability of the object to the power receiving device based on the existence probability of the object determined by the determining means.
- the transmitting means includes information requesting processing related to reacquisition of the parameter in the signal,
- the signal is transmitted, and if the existence probability of the object determined by the determining means is greater than a threshold value, the signal is transmitted without including information requesting processing related to reacquisition of the parameter in the signal.
- Information based on the existence probability of objects different from the power receiving device can be appropriately transmitted from the power transmitting device to the power receiving device.
- FIG. 1 is a diagram illustrating a configuration example of a wireless power transmission system
- FIG. 2 is a block diagram showing a configuration example of a power receiving device
- FIG. It is a block diagram which shows the hardware structural example of a power transmission apparatus. It is a block diagram which shows the functional structural example of a power transmission apparatus.
- 4 is a flowchart of processing executed by a power transmission device; 4 is a flowchart of power transmission control processing executed by a power transmission device;
- FIG. 10 is a diagram showing an operation sequence of the first processing example;
- FIG. 10 is a diagram showing an operation sequence of a second processing example;
- FIG. 1 is a diagram showing a configuration example of a wireless power transmission system 100 according to the first embodiment.
- a wireless power transmission system 100 is a contactless charging system, and includes, for example, a power receiving device 101 , a power transmitting device 102 , and a charging stand 103 .
- the power receiving device 101 is an electronic device that receives power from the power transmitting device 102 and charges an internal battery.
- the power transmitting device 102 is an electronic device that wirelessly transmits power to the power receiving device 101 placed on the charging stand 103 .
- a range 104 indicates a range in which the power receiving apparatus 101 can receive power transmitted from the power transmitting apparatus 102 .
- the power receiving device 101 and the power transmitting device 102 may have a function of executing applications other than contactless charging.
- the power receiving device 101 is, for example, a smartphone
- the power transmitting device 102 is, for example, an accessory device for charging the smartphone.
- the power receiving device 101 and the power transmitting device 102 may be storage devices such as hard disk devices and memory devices, or may be information processing devices such as personal computers (PCs). Further, the power receiving device 101 and the power transmitting device 102 may be, for example, an image input device such as an imaging device (camera, video camera, etc.) or a scanner, or an image output device such as a printer, a copier, or a projector. good too.
- an image input device such as an imaging device (camera, video camera, etc.) or a scanner
- an image output device such as a printer, a copier, or a projector. good too.
- the wireless power transmission system 100 performs wireless power transmission using an electromagnetic induction method for contactless charging based on the WPC standard defined by WPC (Wireless Power Consortium). That is, the power transmission device 102 and the power reception device 101 perform wireless power transmission for contactless charging based on the WPC standard between the power transmission coil of the power transmission device 102 and the power reception coil of the power reception device 101 .
- the wireless power transmission method (non-contact power transmission method) is not limited to the method specified by the WPC standard, and other electromagnetic induction method, magnetic resonance method, electric field resonance method, microwave method, laser, etc. It may be a method. Also, in the present embodiment, wireless power transmission is used for contactless charging, but wireless power transmission may be used for purposes other than contactless charging.
- the amount of received power guaranteed when the power receiving device 101 receives power from the power transmitting device 102 is defined by a value called Guaranteed Power (hereinafter referred to as "GP").
- GP Guaranteed Power
- the GP maintains the load of the power receiving apparatus 101 such as a circuit for charging the power receiving apparatus 101. Indicates the power value guaranteed to be output to
- This power value is the power value agreed between the power transmitting device and the power receiving device.
- the power transmission device 102 can output 15 watts to the load in the power reception device 101 even if the positional relationship between the power receiving coil and the power transmission coil changes and the power transmission efficiency decreases. power is transmitted under control.
- the WPC standard defines a method for the power transmission device 102 to detect the presence of an object (foreign object) other than the power reception device 101 around the power transmission device 102 (in the vicinity of the power reception antenna).
- a foreign object is detected by a method of detecting a foreign object based on a change in the quality factor (Q value) of a power transmitting antenna (power transmitting coil) in the power transmitting device 102, and a foreign object is detected by a difference between the power transmitted by the power transmitting device 102 and the power received by the power receiving device 101.
- a power loss method is stipulated. Foreign object detection based on the Q value is performed before power transmission (Negotiation phase or Renegotiation phase). In addition, the foreign object detection by the power loss method performs Calibration, which will be described later, and based on the data, during power transmission (power transfer phase, which will be described later).
- the metal parts include, for example, a metal frame around the transmitting coil or receiving coil.
- a foreign object in the present embodiment is an object other than the above metal parts, among metals that may generate heat when exposed to wireless power transmitted by the power transmission coil. For example, it is a clip or an IC card.
- the power transmitting device 102 and the power receiving device 101 perform communication for power transmission/reception control based on the WPC standard and communication for device authentication.
- communication for power transmission/reception control based on the WPC standard will be described.
- the WPC standard defines multiple phases, including a Power Transfer phase in which power transfer is performed and a phase before actual power transfer is performed. Communication for necessary power transmission/reception control is performed in each phase.
- the phases before power transmission include a Selection phase, a Ping phase, an Identification and Configuration phase, a Negotiation phase, and a Calibration phase.
- the Identification and Configuration phase is hereinafter referred to as the I&C phase.
- the power transmitting device 102 intermittently transmits an Analog Ping and detects that an object exists within the power transmission range (for example, the power receiving device 101 or conductor piece is placed on the charging stand 103).
- the Ping phase the power transmission device 102 transmits a Digital Ping with higher power than the Analog Ping.
- the magnitude of the Digital Ping is sufficient power to activate the control unit of the power receiving device 101 placed on the power transmitting device 102 .
- the power receiving apparatus 101 notifies the power transmitting apparatus 102 of the magnitude of the received voltage using the Signal Strength Packet.
- the power transmission device 102 recognizes that the object detected in the Selection phase is the power reception device 101 by receiving a response from the power reception device 101 that received the Digital Ping.
- the power transmission device 102 transitions to the I&C phase upon receiving the notification of the received voltage. Also, the power transmission device 102 measures the Q-Factor of the power transmission antenna (power transmission coil) before transmitting the Digital Ping. This measurement result is used when executing the foreign matter detection process using the Q value measurement method.
- the power transmitting apparatus 102 identifies the power receiving apparatus 101 and acquires device configuration information (capability information) from the power receiving apparatus 101 . Therefore, the power receiving apparatus 101 transmits the ID Packet and the Configuration Packet to the power transmitting apparatus 102 .
- the ID Packet contains the identifier information of the power receiving apparatus 101
- the Configuration Packet contains the device configuration information (capability information) of the power receiving apparatus 101 .
- the power transmitting device 102 that has received the ID Packet and the Configuration Packet responds to the power receiving device 101 with an acknowledgment (ACK). Then the I&C phase ends.
- the GP value is determined based on the GP value requested by the power receiving apparatus 101, the power transmission capability of the power transmitting apparatus 102, and the like.
- the power transmission device 102 executes foreign object detection processing using the Q value measurement method in accordance with a request from the power reception device 101 .
- the WPC standard defines a method of once shifting to the Power Transfer phase and then performing the same processing as in the Negotiation phase again according to a request from the power receiving apparatus 101 .
- the phase that moves from the Power Transfer phase and performs these processes is called the Renegotiation phase.
- the power receiving apparatus 101 notifies the power transmitting apparatus 102 of a predetermined received power value (the received power value in the light load state/the received power value in the maximum load state). Make adjustments for power transmission.
- the received power value notified to the power transmission device 102 is used for foreign object detection processing using the power loss method.
- the power transmission device 102 performs control such as continuation of power transmission and stop of power transmission due to an error or full charge.
- the power transmission device 102 and the power reception device 101 perform communication for power transmission/reception control based on the WPC standard, using the same antenna (coil) as for wireless power transmission, and in-band communication in which signals are superimposed.
- the range in which in-band communication based on the WPC standard is possible between the power transmitting apparatus 102 and the power receiving apparatus 101 is substantially the same as the power transmission range. That is, in FIG. 1, a range 104 represents a range where wireless power transmission and in-band communication are possible by the power transmission/reception coils of the power transmission device 102 and the power reception device 101 .
- the power receiving device 101 being “placed” means that the power receiving device 101 has entered the inside of the range 104 . It also includes the state where it is not placed.
- FIG. 11 A foreign matter detection method based on the power loss method defined by the WPC standard will be described using FIG.
- the horizontal axis of FIG. 11 is the transmitted power of the power transmitting apparatus 102 and the vertical axis of FIG. 11 is the received power of the power receiving apparatus 101 .
- the power transmitting device 102 transmits Digital Ping to the power receiving device 101 .
- the power transmitting apparatus 102 receives the received power value Pr1 (referred to as Light Load) received by the power receiving apparatus 101 from the power receiving apparatus 101 as a Received Power Packet (mode 1). At this time, the power receiving device 101 does not supply the received power to the load (charging circuit, battery, etc.).
- Pr1 referred to as Light Load
- the power transmission device 102 stores the received power value Pr1 and the transmitted power value Pt1 at that time as a point 1100 in FIG. 11 .
- the power transmission device 102 linearly interpolates the points 1100 and 1101 in FIG. 11 to create a straight line 1102 .
- a straight line 1102 indicates the relationship between the transmitted power value and the received power value when no foreign object exists around the power transmitting apparatus 102 and the power receiving apparatus 101 . Therefore, based on the transmitted power value and the straight line 1102, the power transmission device 102 can predict the received power value in a state where there is a high possibility that there is no foreign object. For example, when the transmitted power value is Pt3, the power transmission device 102 can predict that the received power value is Pr3 from the point 1103 on the straight line 1102 indicating the transmitted power value Pt3.
- the power transmission apparatus 102 receives the power reception power value Pr3' from the power reception apparatus 101 when the power transmission apparatus 102 transmits power with the power transmission power value Pt3 to the power reception apparatus 101 .
- This Ploss_FO can be considered as the power loss consumed by the foreign object when the foreign object exists between the power transmitting device 102 and the power receiving device 101 . Therefore, when the power Ploss_FO that would have been consumed by the foreign object exceeds a predetermined threshold value, the power transmitting device 102 determines that the foreign object exists.
- the power transmission device 102 After obtaining the straight line 1102 , the power transmission device 102 periodically receives the current received power value (for example, Pr3′) from the power reception device 101 .
- the current received power value periodically transmitted by the power receiving apparatus 101 is transmitted to the power transmitting apparatus 102 as a Received Power Packet (mode 0).
- the power transmission device 102 detects a foreign object based on the received power value stored in the Received Power Packet (mode 0) and the straight line 1102 .
- the above is the description of foreign matter detection based on the power loss method.
- points 1100 and 1101 for obtaining a straight line 1102 representing the relationship between the transmitted power value and the received power value when no foreign object exists around the power transmitting device 102 and the power receiving device 101 are referred to as calibration data points. and express.
- a line segment (straight line 1102) obtained by interpolating at least two calibration data points is expressed as a calibration curve.
- FIG. 2 is a diagram showing a configuration example of the power receiving device 101 according to this embodiment.
- the power receiving device 101 complies with the WPC standard.
- Power receiving device 101 includes, for example, control unit 200 , power receiving coil 201 , rectifying unit 202 , voltage control unit 203 , communication unit 204 , charging unit 205 , battery 206 , resonance capacitor 207 , switch 208 , memory 209 , and timer 210 . have.
- the control unit 200 controls the entire power receiving apparatus 101 by executing a control program stored in the memory 209, for example.
- the control unit 200 may perform control for executing applications other than wireless power transmission.
- the control unit 200 includes one or more processors such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit).
- the control unit 200 includes dedicated hardware for specific processing such as an application specific integrated circuit (ASIC) and an array circuit such as an FPGA (Field Programmable Gate Array) compiled to execute predetermined processing. may be configured to include
- ASIC application specific integrated circuit
- FPGA Field Programmable Gate Array
- the control unit 200 causes the memory 209 to store information to be stored while executing various processes. Control unit 200 also measures time using timer 210 .
- the power receiving coil 201 receives power from the power transmitting coil of the power transmitting device 102 . Also, the receiving coil 201 is connected to a resonance capacitor 207 and resonates at a specific frequency F2.
- the rectifying unit 202 converts AC voltage and AC current from the power transmitting coil of the power transmitting device 102 that receives power through the power receiving coil 201 into DC voltage and DC current.
- Voltage control unit 203 converts the level of the DC voltage input from rectifying unit 202 into a DC voltage level at which control unit 200, charging unit 205 and the like operate.
- the communication unit 204 performs control communication based on the WPC standard as described above by in-band communication with the power transmission device 102 .
- the communication unit 204 demodulates the electromagnetic waves input from the power receiving coil 201 to acquire information transmitted from the power transmission apparatus 102, and load-modulates the electromagnetic waves to obtain information to be transmitted to the power transmission apparatus 102 as electromagnetic waves. , and communicates with the power transmission device 102 . That is, the communication performed by the communication unit 204 is performed by superimposing information on the power transmitted from the power transmission coil 303 of the power transmission device 102 .
- the charging section 205 charges the battery 206 based on the DC voltage supplied from the voltage control section 203 .
- the battery 206 supplies power necessary for control, power reception, and communication to the entire power receiving apparatus 101 . Also, the battery 206 stores electric power received by the charging unit 205 via the power receiving coil 201 .
- a switch 208 is a switch for short-circuiting the receiving coil 201 and the resonance capacitor 207 and is controlled by the control section 200 .
- switch 208 When switch 208 is turned on, receiving coil 201 and resonance capacitor 207 form a series resonance circuit. At this time, current flows only through the closed circuit of power receiving coil 201 , resonance capacitor 207 and switch 208 , and current does not flow through rectifying section 202 and voltage control section 203 .
- switch 208 is turned off, current flows through rectifying section 202 and voltage control section 203 via power receiving coil 201 and resonance capacitor 207 .
- the memory 209 stores various information as described above. Note that the memory 209 may store information obtained by a functional unit different from the control unit 200 .
- the timer 210 measures time by, for example, a count-up timer that measures the elapsed time from the start time, a count-down timer that counts down from a set time, or the like.
- FIG. 3 is a diagram showing a hardware configuration example of the power transmission device 102 according to this embodiment.
- the power transmission device 102 has, as an example, a control unit 300, a power supply unit 301, a power transmission unit 302, a power transmission coil 303, a communication unit 304, a resonance capacitor 305, a switch 306, a memory 307, and a timer 308.
- the control unit 300 controls the entire power transmission device 102 by executing a control program stored in the memory 307, for example.
- the control unit 300 may perform control for executing applications other than wireless power transmission.
- the control unit 300 includes one or more processors such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit).
- the control unit 300 includes dedicated hardware for specific processing, such as an application-specific integrated circuit (ASIC), and an array circuit such as an FPGA (Field Programmable Gate Array) compiled to execute predetermined processing. may be configured to include
- the control unit 300 causes the memory 307 to store information to be stored while executing various processes. Also, the control unit 300 measures time using a timer 308 .
- the power supply unit 301 supplies power necessary for control, power transmission, and communication to the entire power transmission device 102 .
- the power supply unit 301 is, for example, a commercial power supply or a battery.
- Power transmission unit 302 converts the DC power or AC power input from power supply unit 301 into AC frequency power in the frequency band used for wireless power transmission, and inputs the AC frequency power to power transmission coil 303, whereby power receiving apparatus It generates an electromagnetic wave for receiving power to 101 .
- the frequency of the AC power generated by the power transmission unit 302 is approximately several hundred kHz (eg, 110 kHz to 205 kHz).
- the power transmission unit 302 Based on an instruction from the control unit 300 , the power transmission unit 302 inputs AC frequency power to the power transmission coil 303 so that the power transmission coil 303 outputs an electromagnetic wave for transmitting power to the power receiving apparatus 101 . Further, the power transmission unit 302 controls the intensity of the electromagnetic wave to be output by adjusting the voltage (transmission voltage) or current (transmission current) input to the power transmission coil 303 .
- the power transmission unit 302 increases the power transmission voltage or power transmission current, the strength of the electromagnetic waves increases, and when the power power transmission unit 302 decreases the power transmission voltage or power transmission current, the strength of the electromagnetic waves decreases.
- the power transmission unit 302 performs output control of AC frequency power so that power transmission from the power transmission coil 303 is started or stopped.
- the power transmission coil 303 is connected to a resonance capacitor 305 and resonates at a specific frequency F1.
- the communication unit 304 performs control communication based on the WPC standard as described above with the power receiving apparatus 101 by in-band communication.
- the communication unit 304 modulates the electromagnetic wave output from the power transmission coil 303 and transmits information to the power receiving apparatus 101 .
- the communication unit 304 also acquires information transmitted by the power receiving apparatus 101 by demodulating the electromagnetic wave that is output from the power transmitting coil 303 and modulated in the power receiving apparatus 101 . That is, the communication performed by the communication unit 304 is performed by superimposing information on the power transmitted from the power transmission coil 303 .
- a switch 306 is a switch for short-circuiting the power transmission coil 303 and the resonance capacitor 305 and is controlled by the control section 300 .
- switch 306 When switch 306 is turned on, power transmission coil 303 and resonance capacitor 305 form a series resonance circuit. At this time, current flows only through the closed circuit of power transmission coil 303 , resonance capacitor 305 and switch 306 .
- switch 306 When switch 306 is turned off, power is supplied from power transmission section 302 to power transmission coil 303 and resonance capacitor 305 .
- the memory 307 stores various information as described above. Note that the memory 307 may store information obtained by a functional unit different from the control unit 300 .
- the timer 308 measures time by, for example, a count-up timer that measures elapsed time from the start time, a count-down timer that counts down from a set time, or the like.
- FIG. 4 is a block diagram showing a functional configuration example of the control unit 300 of the power transmission device 102.
- the power transmission device 102 has a communication processing unit 401, a power transmission processing unit 402, a foreign object detection processing unit 403, and a notification processing unit 404 as processing units that function when the control unit 300 executes a program.
- the communication processing unit 401 is a processing unit that performs control communication with the power receiving device 101 based on the WPC standard via the communication unit 304 .
- a power transmission processing unit 402 is a processing unit that controls the power transmission unit 302 and controls power transmission to the power receiving apparatus 101 .
- the foreign object detection processing unit 403 is a processing unit that measures the power loss between the power transmission device 102 and the power reception device 101 and the Q value in the power transmission coil 303 to detect foreign objects.
- the foreign object detection processing unit 403 can realize a foreign object detection function by a power loss method and a foreign object detection function by a Q value measurement method. Also, the foreign object detection processing unit 403 may perform the foreign object detection process using another technique.
- the foreign object detection processing unit 403 may perform foreign object detection processing using a counterpart device detection function based on the NFC standard in the power transmission device 102 having an NFC (Near Feald Communication) communication function. Further, the foreign matter detection processing unit 403 can also detect foreign matter by the Q-value measurement method in the time domain, which will be described later. Furthermore, the foreign object detection processing unit 403 can also detect that the state of the power transmission device 102 has changed as a function other than detecting a foreign object. For example, the foreign object detection processing unit 403 can also detect an increase or decrease in the number of power receiving apparatuses 101 on the power transmitting apparatus 102 .
- the foreign object detection processing unit 403 measures the power output to the power receiving apparatus 101 via the power transmission unit 302 and receives the average output power value calculated per unit time from the power receiving apparatus 101 via the communication processing unit 401 . Based on the difference between the received electric power values, foreign object detection processing is performed using the power loss method.
- the notification processing unit 404 is a processing unit that notifies the power receiving apparatus 101 of information regarding foreign object detection (hereinafter referred to as foreign object detection information) via the communication processing unit 401 .
- the foreign matter detection information includes information indicating the existence probability of a foreign matter that can be calculated based on the index derived by the foreign matter detection processing unit 403, but is not limited to this.
- the foreign object detection information may include information indicating a request to start the foreign object detection process.
- the foreign object detection information may include information requesting re-execution or additional execution of calibration according to the existence probability of the foreign object, or information requesting stop of receiving power or suppression of received power. may
- the functions of the communication processing unit 401, the power transmission processing unit 402, the foreign object detection processing unit 403, and the notification processing unit 404 are realized by the control unit 300 executing a program.
- Each processing unit functions as an independent program, and can operate in parallel while synchronizing the programs by event processing or the like.
- FIG. 5 is a flow chart showing a control method for the power transmission device 102 .
- the processing in FIG. 5 is implemented by executing a program read from the memory 307 by the control unit 300 of the power transmission device 102, for example.
- the processing in FIG. 5 may be implemented by hardware.
- the hardware in this case can be realized by, for example, using a predetermined compiler to automatically generate a dedicated circuit using a gate array circuit such as FPGA from a program for realizing each processing step. Further, the processing in FIG.
- FIG. 5 is performed in response to the power of the power transmission device 102 being turned on, in response to the user of the power transmission device 102 inputting an instruction to start the wireless power transfer application, or in response to the power transmission device 102 Executed in response to being connected to and powered by commercial power. Also, the process of FIG. 5 may be started by other triggers.
- step S ⁇ b>501 the control unit 300 executes processing specified as the Selection phase and Ping phase of the WPC standard, and waits for an object to be placed on the power transmission device 102 .
- the control unit 300 uses the power transmission unit 302 to repeatedly and intermittently transmit the WPC-standard Analog Ping to detect an object existing within the power transmission range.
- the power transmission unit 302 transmits a WPC standard Digital Ping.
- the control unit 300 determines that the detected object is the power receiving device 101 and that the power receiving device 101 is placed on the charging stand 103, and proceeds to step S502.
- the control unit 300 receives the identification information and capability information of the power receiving device 101 from the power receiving device 101 through the communication of the configuration phase defined by the WPC standard of the communication unit 304.
- the identification information includes Manufacturer Code and Basic Device ID.
- the capability information includes information that can identify the supported WPC standard version, Maximum Power Value that identifies the maximum power that the power receiving apparatus 101 can supply to the load, and whether or not the power receiving apparatus 101 has the WPC standard Negotiation function. including information to indicate Note that these are only examples, and the identification information and capability information of the power receiving apparatus 101 may be replaced by other information, or may include other information in addition to the above information.
- the identification information may be any other identification information that can identify the individual power receiving device 101, such as a Wireless Power ID.
- the control unit 300 may acquire the identification information and the capability information of the power receiving apparatus 101 by a method other than communication in the configuration phase of the WPC standard.
- step S503 the control unit 300 executes negotiation with the power receiving apparatus 101 through communication in the Negotiation phase defined by the WPC standard, and determines the GP value.
- the control unit 300 may execute other procedures for determining the GP, not limited to communication in the Negotiation phase of the WPC standard.
- the control unit 300 acquires information indicating that the power receiving apparatus 101 does not support the Negotiation phase (for example, in step S502), the control unit 300 may set the value of GP to a prescribed small value without performing communication in the Negotiation phase.
- the specified small value is, for example, a value predefined in the WPC standard.
- control unit 300 executes the Calibration phase based on the determined GP value.
- control unit 300 derives the relationship between the transmitted power value and the received power value in the absence of a foreign object. Specifically, based on the WPC standard, the control unit 300 uses a predetermined received power value acquired from the power receiving device 101 to indicate the power loss between the power transmitting device 102 and the power receiving device 101 in the absence of foreign objects. Derive the data (power loss data). For example, control unit 300 derives straight line 1102 in FIG.
- the predetermined received power value includes the received power value in the light load state/Light Load and the received power value in the maximum load/Connected Load state.
- the description of foreign object detection based on the power loss method is as described above. That is, the control unit 300 determines that the amount of power loss between the power transmitting apparatus 102 and the power receiving apparatus 101 during power transmission, which is calculated based on the calibration curve and the received power value of the power receiving apparatus 101 received during power transmission, is greater than or equal to a predetermined threshold. If so, it is determined that there is a "foreign object”. Foreign matter detection is performed in step S604 of FIG. 6, which will be described later.
- step S505 the control unit 300 starts power transmission by the power transmission unit 302. Power transmission is performed by processing in the Power Transfer phase.
- the control unit 300 is not limited to this, and may transmit power using a method other than the WPC standard.
- step S506 the control unit 300 executes power transmission control processing.
- the power transmission control process will be described later with reference to FIG.
- the control unit 300 determines whether or not the power receiving apparatus 101 is placed on the power transmitting apparatus 102 . When the control unit 300 determines that the power receiving apparatus 101 is not placed on the power transmitting apparatus 102, the process returns to the Selection phase of step S501.
- the control unit 300 receives a WPC standard End Power Transfer from the power receiving apparatus 101, the control unit 300 ends the processing in any processing phase according to the WPC standard, stops power transmission, and returns to the Selection phase of step S501. . Note that the control unit 300 returns to the Selection phase in step S501 because the power receiving apparatus 101 also transmits the End Power Transfer when the power receiving apparatus 101 is fully charged.
- FIG. 6 is a flowchart showing the details of the power transmission control process in step S506 of FIG.
- the processing in FIG. 6 is implemented by executing a program read from the memory 307 by the control unit 300 of the power transmission device 102, for example.
- the hardware in this case can be realized by, for example, using a predetermined compiler to automatically generate a dedicated circuit using a gate array circuit such as FPGA from a program for realizing each processing step.
- step S ⁇ b>601 the control unit 300 determines whether or not a WPC standard Control Error Packet (hereinafter referred to as a CE packet) has been received from the power receiving apparatus 101 when the process is started.
- the CE packet is a message that instructs the power receiving apparatus 101 to change the power transmission output to the power transmitting apparatus 102 by including the Control Error Value that indicates the amount of voltage change.
- the Control Error Value is a positive value when increasing the power transmission output, a negative value when decreasing the power transmission output, and 0 when the power transmission output is not changed. If the control unit 300 has received a CE packet (YES in S601), the process proceeds to step S602, and if it has not received a CE packet (NO in S601), the process proceeds to step S603.
- step S602 the control unit 300 changes the power value of the power transmission output based on the amount of change indicated by the CE packet, and proceeds to step S603.
- step S ⁇ b>603 the control unit 300 determines whether or not a WPC standard Received Power Packet (hereinafter referred to as an RP packet) has been received from the power receiving apparatus 101 .
- the RP packet is a message for notifying the power transmitting apparatus 102 of the received power value actually received by the power receiving apparatus 101 at that time. If an RP packet has been received (YES in S603), the control unit 300 proceeds to step S604, and if an RP packet has not been received (NO in S603), the processing in FIG. 6 ends.
- step S604 the control unit 300 performs foreign matter detection processing and calculates the existence probability of foreign matter.
- the foreign matter existence probability is calculated by the ratio of the power loss amount error to the power loss value on the calibration curve, "
- the control unit 300 may weight the calculated existence probability according to the absolute value of the transmitted power value. For example, the control unit 300 multiplies the existence probability by a coefficient that lowers the existence probability when the transmitted power value is small, and multiplies the existence probability by a coefficient that increases the existence probability when the transmitted power value is large.
- control unit 300 may set the existence probability of a foreign object to 100% regardless of the calculated existence probability.
- the control unit 300 can reliably can be notified to the power receiving apparatus 101 that there is a possibility that
- step S605 the control unit 300 determines whether or not the probability of existence of foreign matter is greater than or equal to the first threshold. If the foreign object existence probability is greater than or equal to the first threshold (YES in S605), control unit 300 proceeds to step S606. move on.
- step S606 the control unit 300 transmits to the power receiving apparatus 101 a response indicating that there is a notification in response to the RP packet received in step S603, and proceeds to step S607.
- step S ⁇ b>607 the control unit 300 transmits foreign object detection information that does not include information indicating a request to start processing, that is, only information indicating the presence probability of a foreign object (information indicating a request to start processing is 0) to the power receiving apparatus 100 .
- the information indicating the existence probability of foreign matter is a value obtained by converting the value calculated in step S604 into a value expressed in a predetermined range (section) (for example, a value in increments of 0 to 10). , but not limited to this.
- the control unit 300 does not include information indicating a request to start processing on the premise of continuing power transmission/reception in the foreign object detection information. It is possible to reduce the possibility of heat generation, ignition, etc. due to the continuation of this.
- the control unit 300 transmits the foreign object detection information that does not include the information indicating the request to start the above processing, the processing of FIG. 6 ends.
- step S608 the control unit 300 determines whether or not the probability of existence of foreign matter is equal to or greater than the second threshold.
- the second threshold is a value smaller than the first threshold. That is, the probability of foreign matter indicated by the second threshold is lower than the existence probability of foreign matter indicated by the first threshold.
- the first threshold and the second threshold may be the same value, and the second threshold is less than or equal to the first threshold. If the foreign object existence probability is greater than or equal to the second threshold (YES in S608), control unit 300 proceeds to step S612. move on.
- step S609 the control unit 300 determines whether the received power value of the power receiving apparatus 101 in the RP packet received in step S603 is greater than a predetermined ratio with respect to the maximum received power value (Pr2 in FIG. 11) of the calibration curve 1102. determine whether If the ratio is greater than the predetermined rate (YES in S609), the control unit 300 proceeds to step S610, and if not greater than the predetermined rate (NO in S609), the process proceeds to step S614.
- step S609 the control unit 300 determines whether or not the received power value is greater than a predetermined ratio with respect to the maximum received power value of the calibration curve 1102, but the present invention is not limited to this.
- the control unit 300 may determine whether the difference between the received power value and the maximum received power value of the calibration curve 1102 is equal to or greater than a threshold, or the received power value may be the maximum received power value of the calibration curve 1102. You may judge whether it is larger than a value.
- step S610 the control unit 300 transmits to the power receiving apparatus 101 a response indicating that there is a notification in response to the RP packet received in step S603, and proceeds to step S611.
- step S611 the control unit 300 transmits, to the power receiving apparatus 101, foreign object detection information including information indicating a request to start additional execution of calibration in addition to information indicating the presence probability of a foreign object, and ends the processing in FIG. .
- step S612 the control unit 300 determines whether or not the timer 308 has started timekeeping. If timer 308 has started time measurement (YES in S612), control unit 300 proceeds to step S616. If timer 308 has not started time measurement (NO in S612), control unit 300 proceeds to step S613.
- control unit 300 starts timing of the timer 308, and proceeds to step S617.
- step S614 the control unit 300 determines whether or not the timer 308 has started timekeeping. If the timer 308 has started timekeeping (YES in S614), the control unit 300 proceeds to step S615, and if not (NO in S614), the control unit 300 proceeds to step S617.
- step S615 the control unit 300 stops the timer 308 from measuring time, and proceeds to step S617.
- step S616 the control unit 300 determines whether or not a predetermined period of time has elapsed after the timer 308 started timing in step S613. If the predetermined time has passed (YES in S616), the control unit 300 proceeds to step S618, and if the predetermined time has not passed (NO in S616), the process proceeds to step S617.
- step S617 the control unit 300 transmits ACK, which is an acceptance response to the RP packet received in step S603, to the power receiving apparatus 101, and ends the processing in FIG.
- step S618 the control unit 300 transmits to the power receiving apparatus 101 a response indicating that there is a notification in response to the RP packet received in step S603, and proceeds to step S619.
- step S ⁇ b>619 the control unit 300 transmits to the power receiving apparatus 101 foreign object detection information including information indicating a request to start re-executing Calibration in addition to information indicating the presence probability of a foreign object.
- the control unit 300 performs control to re-derivate the calibration curve when the foreign matter existence probability is not equal to or higher than the first threshold value but is equal to or higher than the second threshold value for a predetermined period of time.
- a change in the characteristics of the calibration curve means a change in the slope or intercept of the curve.
- the control unit 300 can calculate an appropriate amount of power loss, that is, detect a foreign object with high precision, as compared to the case where the calibration curve whose characteristics have changed is continuously used.
- a wireless power transmission system 100 can be implemented.
- control unit 300 appropriately controls the process start request according to the foreign object existence probability calculated by the foreign object detection process, thereby realizing safer and more efficient wireless power.
- a transmission system 100 can be implemented.
- the GP is determined to be 5 watts in the first Negotiation phase, and power transmission is started. Then, after power transmission is started, GP is re-determined to 15 watts by re-executing the Negotiation phase.
- the received power value in the power receiving apparatus 101 increases according to the re-determined GP, and the received power value becomes larger than a predetermined ratio with respect to the maximum received power value (ie, 5 watts) of the calibration curve 1102 .
- the power transmitting apparatus 102 transmits, to the power receiving apparatus 101, foreign object detection information including information indicating a request to start additional execution of calibration in addition to information indicating the presence probability of a foreign object.
- the predetermined percentage for determining that a request to start additional execution of Calibration is issued is 20%, but this is merely an example and may be another value.
- FIG. 7 is a diagram showing the operation sequence of the power transmission device 102 and the power reception device 101 in the first processing example.
- the power transmission device 102 waits for an object to be placed on the power transmission device 102 by transmission of Analog Ping (S501).
- step F702 the power receiving device 101 is placed on the power transmitting device 102. Then, in step F703, the Analog Ping transmitted by the power transmission device 102 changes. In step F704, the power transmission device 102 detects that an object has been placed on the power transmission device 102 when the Analog Ping changes. In step F705, the power transmission device 102 transmits Digital Ping.
- step F706 the power receiving apparatus 101 detects that the power receiving apparatus 101 is placed on the power transmitting apparatus 102 by receiving the Digital Ping. Also, the power transmitting device 102 detects that the placed object is the power receiving device 101 from the digital ping response of the power receiving device 101 .
- step F707 the power transmitting apparatus 102 receives identification information and capability information from the power receiving apparatus 101 through communication in the configuration phase (S502).
- step F708 the power transmitting apparatus 102 and the power receiving apparatus 101 perform Negotiation phase communication and determine GP to be 5 watts (S503).
- step F709 the power transmitting apparatus 102 and the power receiving apparatus 101 derive the calibration curve 1102 through calibration phase communication (S504).
- the power transmission device 102 starts power transmission and power transmission control processing (S505, S506).
- step F710 the power transmitting apparatus 102 receives a CE packet whose Control Error Value is 0 from the power receiving apparatus 101 (YES in S601), and does not change the power transmission output according to the Control Error Value (S602).
- step F711 the power transmitting apparatus 102 receives an RP packet (mode 0) with a received power value of 5 watts from the power receiving apparatus 101 (YES in S603), performs foreign object detection processing, and calculates the existence probability of a foreign object (S604). ).
- the existence probability of foreign matter is 0%.
- step F712 the power transmission device 102 determines that the foreign object existence probability is 0%, is less than the first and second threshold values (NO in S605, NO in S608), and the received power value is not greater than a predetermined ratio. (NO in S609). Further, the power transmitting apparatus 102 determines that the timer 308 has not started timing (NO in S614), and responds ACK to the power receiving apparatus 101 (S617).
- step F713 the power transmitting apparatus 102 and the power receiving apparatus 101 perform Negotiation phase communication again and determine the GP to be 15 watts.
- step F714 the power transmitting apparatus 102 receives a CE packet whose Control Error Value is a positive value from the power receiving apparatus 101 (YES in S601).
- the power transmission device 102 increases the power transmission output according to the Control Error Value (S602).
- step F716 the power transmitting apparatus 102 receives an RP packet (mode 0) with a received power value of 6 watts from the power receiving apparatus 101 (YES in S603), performs foreign object detection processing, and calculates the existence probability of a foreign object (S604). ).
- step F717 the power transmission device 102 determines that the foreign object existence probability is less than the first and second threshold values (NO in S605, NO in S608) and that the received power value is greater than a predetermined ratio (YES in S609). , to notify foreign object detection information.
- step F718 the power transmitting apparatus 102 transmits a response indicating that there is notification to the power receiving apparatus 101 (S610).
- step F719 the power transmitting apparatus 102 transmits foreign object detection information including information indicating a request to start additional execution of calibration to the power receiving apparatus 101 because the current probability of existence of a foreign object is 0 (S611).
- the power receiving apparatus 101 starts additional execution of Calibration.
- step F720 the power transmission device 102 receives additional calibration information with a received power value of 6 watts.
- step F721 the power transmitting apparatus 102 accepts the above additional configuration information as values forming the calibration curve 1102, extends the end points of the calibration curve 1102, and responds ACK to the power receiving apparatus 101.
- the additional calibration information is an RP packet (mode 2), it is not limited to this.
- the additional calibration information may be an RP packet of another mode, or a received power value as an additional value constituting the calibration curve 1102 may be notified using a packet different from the RP packet. good.
- steps F722 to F725 is the same as the processing of steps F714, F715, F720, and F721, so description thereof will be omitted.
- step F726 the power transmission device 102 receives an RP packet (mode 0) with a received power value of 15 watts.
- step F727 the power transmitting apparatus 102 determines that additional execution of Calibration has been completed normally, responds ACK to the power receiving apparatus 101, and restarts the power transmission control process.
- the power transmission device 102 when the probability of presence of a foreign object is not equal to or greater than the first and second thresholds and the received power value is greater than a predetermined ratio with respect to the maximum received power value of the calibration curve 1102, the power transmission device 102
- the detection information includes information indicating a request to start processing.
- the power transmission apparatus 102 can avoid power transmission at a received power value that deviates from the calibration curve 1102 while increasing the power transmission output after confirming that the probability of inclusion of a foreign object is low.
- the power transmission device 102 can realize a safer and more efficient wireless power transmission system 100 .
- the GP is determined to be 5 watts in the first Negotiation phase, and power transmission is started. After the start of power transmission, the GP is re-determined to be 15 watts by re-executing the Negotiation phase. After that, the received power value of the power receiving apparatus 101 becomes larger than a predetermined ratio with respect to the maximum received power value (that is, 5 watts) of the calibration curve 1102 . At this time, as a result of the foreign object detection process, the power transmitting apparatus 102 transmits a request to start additional execution of calibration to the power receiving apparatus 101 without including the foreign object detection information because the presence probability of the foreign object is greater than or equal to the first threshold. Note that the first threshold is 75%, and the predetermined percentage for determining that a request to start additional execution of Calibration is made is 20%. good.
- FIG. 8 is a diagram showing the operation sequence of the power transmission device 102 and the power reception device 101 in the second processing example.
- the processing of steps F801 to F815 is the same as the processing of steps F701 to F715 in FIG. 7, so description thereof will be omitted.
- step F816 a foreign object enters the range 104 of the power transmission device 102.
- step F817 the power transmitting apparatus 102 receives an RP packet (mode 0) with a received power value of 6 watts from the power receiving apparatus 101 (YES in S603), performs foreign object detection processing, and calculates the existence probability of a foreign object (S604). ).
- step F818 the power transmission apparatus 102 determines that foreign object detection information is to be notified because the foreign object existence probability is 80%, which is equal to or greater than 75% of the first threshold (YES in S605).
- step F819 the power transmitting apparatus 102 transmits a response indicating that there is notification to the power receiving apparatus 101 (S606).
- step F820 the power transmitting apparatus 102 transmits to the power receiving apparatus 101 foreign object detection information that does not include information indicating a request to start processing, that is, includes only information indicating the probability of presence of a foreign object (S607).
- step F ⁇ b>821 the power receiving apparatus 101 determines to stop power transmission/reception because the presence probability of the foreign object included in the received foreign object detection information is high, and transmits an End Power Transfer (EPT) to the power transmitting apparatus 102 .
- the power transmitting apparatus 102 receives the EPT and stops power transmission to the power receiving apparatus 101 .
- the power transmission apparatus 102 does not include information indicating a request to start a process that assumes continuation of power transmission/reception in the foreign object detection information when the existence probability of a foreign object is equal to or greater than the first threshold. That is, control is performed so that the contents of the foreign object detection information are not inconsistent.
- the power receiving apparatus 101 that has received the foreign object detection information can appropriately determine processing according to the probability of presence of a foreign object.
- a safe wireless power transmission system 100 can be realized.
- the power transmission apparatus 102 unconditionally notifies foreign object detection information that does not include information indicating a request to start processing when the existence probability of a foreign object is equal to or greater than the first threshold.
- Information indicating a request such as suppression of received power may be included in the foreign object detection information and notified.
- the power receiving apparatus 101 can notify the power transmitting apparatus 102 of a request to start a process that does not presuppose the continuation of power transmission/reception or a process that reduces the power transmission output. It is possible to reduce the possibility of heat generation, ignition, or the like.
- the power receiving apparatus 101 transmits an EPT to the power transmitting apparatus 102, and the power transmitting apparatus 102 stops power transmission. You can choose not to.
- the power transmission device 102 may control to reduce transmitted power and received power. As a result, the power transmitting apparatus 102 and the power receiving apparatus 101 can continue power transmission and reception while suppressing the possibility of heat generation, ignition, and the like.
- the power transmitting apparatus 102 waits for the power receiving apparatus 101 to start processing. .
- the power transmission device 102 can reduce the possibility of heat generation, ignition, or the like occurring at an earlier timing when a foreign object is present with a high probability.
- the GP is determined to be 15 watts in the first Negotiation phase, and power transmission is started. After power transmission is started, the state in which the existence probability of a foreign object is not equal to or higher than the first threshold but is equal to or higher than the second threshold continues for a predetermined time or longer. At this time, the power transmitting apparatus 102 determines that the characteristics of the calibration curve 1102 have changed due to heat generation, positional displacement of the power receiving apparatus 101, or the like.
- the power transmitting apparatus 102 transmits, to the power receiving apparatus 101, foreign object detection information including information indicating a request to start re-executing calibration in addition to the information indicating the presence probability of a foreign object.
- the first threshold is 75%
- the second threshold is 25%.
- the first threshold may be the same as the second threshold.
- FIG. 9 is a diagram showing the operation sequence of the power transmission device 102 and the power reception device 101 in the third processing example.
- the processing of steps F901 to F907 is the same as the processing of steps F701 to F707 in FIG. 7, so description thereof will be omitted.
- step F908 the power transmitting apparatus 102 and the power receiving apparatus 101 perform Negotiation phase communication and determine the GP to be 15 watts (S503).
- step F909 the power transmitting apparatus 102 and the power receiving apparatus 101 derive the calibration curve 1102 through calibration phase communication (S504).
- step F910 the power transmitting apparatus 102 receives a CE packet whose Control Error Value is 0 from the power receiving apparatus 101 (YES in S601), and does not change the power transmission output according to the Control Error Value (S602).
- step F911 the power transmitting apparatus 102 receives an RP packet (mode 0) with a received power value of 15 watts from the power receiving apparatus 101 (YES in S603), performs foreign object detection processing, and calculates the existence probability of a foreign object (S604). ).
- the existence probability of foreign matter is 0%.
- step F912 the power transmission device 102 determines that the foreign object existence probability is 0%, is less than the first and second threshold values (NO in S605, NO in S608), and the received power value is not greater than a predetermined ratio. (NO in S609). Further, the power transmitting apparatus 102 determines that the timer 308 has not started timing (NO in S614), and responds ACK to the power receiving apparatus 101 (S617).
- step F913 the power transmitting apparatus 102 receives a CE packet whose Control Error Value is a positive value from the power receiving apparatus 101 (YES in S601).
- step F914 the power transmission device 102 increases the power transmission output according to the Control Error Value (S602).
- step F915 the power transmitting apparatus 102 receives an RP packet (mode 0) with a received power value of 15 watts from the power receiving apparatus 101 (YES in S603), performs foreign object detection processing, and calculates the existence probability of a foreign object (S604). ). For example, it is assumed that the received power value remains at 15 watts with respect to the increase in the transmission output in step F914, the power loss is increasing, and the existence probability of a foreign object is 40%.
- step F916 the power transmitting apparatus 102 has a foreign object presence probability of 40%, which is less than the first threshold and greater than or equal to the second threshold (NO in S605, YES in S608), and starts the timer 308 to count time. It is determined that it has not been completed (NO in S612). Then, the power transmitting apparatus 102 starts timing of the timer 308 (S613), and responds ACK to the power receiving apparatus 101 (S617).
- step F917 the power transmitting apparatus 102 receives again the RP packet (mode 0) with the received power value of 15 watts from the power receiving apparatus 101 (YES in S603), performs foreign object detection processing, and calculates the foreign object existence probability ( S604). For example, it is assumed that the power loss continues to increase and the probability of existence of a foreign object is 40%.
- step F918 the power transmission device 102 determines that the foreign object existence probability is 40%, which is less than the first threshold and greater than or equal to the second threshold (NO in S605, YES in S608). Then, the power transmitting apparatus 102 determines that a predetermined time has elapsed since the timer 308 started timing (YES in S612, YES in S616), and determines to notify foreign object detection information.
- step F919 the power transmitting apparatus 102 transmits a response indicating that there is notification to the power receiving apparatus 101 (S618).
- step F920 the power transmitting apparatus 102 transmits, to the power receiving apparatus 101, foreign object detection information including information indicating a request to start re-executing Calibration in addition to information indicating the presence probability of a foreign object (S619).
- step F921 the power transmitting apparatus 102 and the power receiving apparatus 101 re-derive the calibration curve 1102 through calibration phase communication.
- step F922 the power transmission device 102 receives an RP packet (mode 0) with a received power value of 15 watts.
- step F923 the power transmitting apparatus 102 responds with ACK to the power receiving apparatus 101 and resumes power transmission control processing.
- the power transmission apparatus 102 performs calibration when there is a possibility that power loss has occurred due to the influence of heat generation, positional displacement of the power receiving apparatus 101, or the like, although the presence probability of a foreign object is not equal to or greater than the first threshold.
- Foreign object detection information including information indicating a request to start re-execution of is transmitted.
- the power transmission device 102 can derive an appropriate calibration curve 1102 according to the characteristics after the change, and can perform foreign object detection with higher accuracy than when the same calibration curve 1102 is continuously used. It can be carried out.
- the power transmission device 102 detects the presence of the foreign object including information indicating a request to start re-executing calibration. The detection information is transmitted to the power receiving apparatus 101 .
- the power transmitting apparatus 102 immediately transmits foreign object detection information including information indicating a request to start re-executing calibration to the power receiving apparatus 101 . may be sent to As a result, the power transmitting apparatus 102 can shorten the period during which foreign object detection is performed using the same calibration curve 1102 .
- the wireless power transmission system 100 has the power transmitting device 102 that wirelessly transmits power to the power receiving device 101 and the power receiving device 101 that wirelessly receives power from the power transmitting device 102 .
- the control unit 300 receives from the power receiving apparatus 101 received power values Pr ⁇ b>1 and Pr ⁇ b>2 of the power receiving apparatus 101 when power with different transmitted power values Pt ⁇ b>1 and Pt ⁇ b>2 are transmitted to the power receiving apparatus 101 in order.
- control unit 300 functions as a deriving unit, and derives a characteristic line indicating the relationship between the transmitted power value and the received power value based on the transmitted power values Pt1, Pt2 and the received power values Pr1, Pr2.
- a characteristic line is a calibration curve 1102 .
- step S603 of FIG. 6 the control unit 300 functions as an acquisition unit and acquires a parameter (the received power value of the power receiving apparatus 101) used for determining the presence probability of a foreign object.
- the existence probability of a foreign object is the existence probability of an object different from the power receiving device 101 .
- the control unit 300 functions as a determination unit and determines the presence probability of foreign matter based on the parameters acquired at step S603.
- step S609 if the received power value of the power receiving apparatus 101 is greater than the first received power value, the control unit 300 proceeds to step S610. The process proceeds to step S614.
- step S608 if the foreign matter existence probability determined in step S604 is smaller than the first threshold and larger than the second threshold, the control unit 300 proceeds to step S612.
- the second threshold is less than the first threshold.
- step S609 the control unit 300 determines that the presence probability of the foreign object determined in step S604 is smaller than the first threshold and smaller than the second threshold, and the received power value of the power receiving apparatus 101 is the first received power. If it is greater than the power value, proceed to step S610. In addition, the control unit 300 determines that the presence probability of the foreign object determined in step S604 is smaller than the first threshold and smaller than the second threshold, and the received power value of the power receiving apparatus 101 is equal to the first received power value. If less, proceed to step S614.
- step S616 if the foreign matter existence probability determined in step S604 is lower than the first threshold and higher than the second threshold continues for a predetermined period of time, the control unit 300 proceeds to step S618.
- control unit 300 functions as a transmitting unit and receives a foreign object detection signal including information for specifying the foreign object existence probability based on the foreign object existence probability determined in step S604. Send to device 101 .
- step S611 the control unit 300 transmits a foreign object detection signal including information requesting processing related to additional parameter acquisition in the foreign object detection signal.
- step S619 control unit 300 transmits a foreign object detection signal including information requesting processing related to parameter reacquisition in the foreign object detection signal.
- step S607 the control unit 300 transmits the foreign object detection signal without including information requesting processing related to reacquisition of parameters and information requesting processing related to additional acquisition of parameters in the foreign object detection signal.
- step F917 the control unit 300 functions as a calculation unit, and upon receiving the received power value of the power receiving apparatus 101 from the power receiving apparatus 101, calculates the existence probability of an object different from the power receiving apparatus 101 based on the characteristic line.
- the existence probability of an object is the existence probability of a foreign object.
- the control unit 300 functions as a transmission unit, and transmits to the power receiving apparatus 101 the object existence probability and a request for re-derivation of the characteristic line based on the object existence probability.
- the characteristic line re-derivation request is a calibration re-execution start request. Specifically, when the object existence probability (40%) is not equal to or greater than the first threshold and is equal to or greater than the second threshold, the control unit 300 re-derives the object existence probability and the characteristic line. A request is sent to the power receiving device 101 .
- the second threshold is less than the first threshold.
- the control unit 300 requests re-derivation of the existence probability of the object and the characteristic line. may be transmitted to the power receiving apparatus 101 .
- Step F921 is processing after transmission in step F920.
- the control unit 300 receives from the power receiving apparatus 101 the received power values of the power receiving apparatus 101 when power with different transmitted power values is sequentially transmitted to the power receiving apparatus 101, and determines the relationship between the received power values and the transmitted power values. Derive the characteristic line shown.
- step F820 the control unit 300 functions as a transmission unit, does not transmit a characteristic line rederive request to the power receiving apparatus 101 when the object existence probability (80%) is equal to or greater than the first threshold, The object existence probability is transmitted to the power receiving apparatus 101 .
- step S609 If the object existence probability (0%) is not equal to or greater than the second threshold (NO in S608) and the received power value received in step S603 is greater than the maximum received power value Pr2 of the characteristic line, the control unit 300 (YES in S609), the process proceeds to step S610.
- step S609 the control unit 300 may proceed to step S610 when the received power value received in step S603 is greater than a predetermined ratio with respect to the maximum received power value Pr2 of the characteristic line. Further, in step S609, when the value obtained by subtracting the maximum received power value Pr2 of the characteristic line from the received power value received in step S603 is larger than a predetermined value, the control unit 300 may proceed to step S610.
- step S611 the control unit 300 functions as a transmission unit and transmits a request for addition of the existence probability of the object and the received power value of the characteristic line to the power receiving apparatus 101 (F719).
- the request to add the received power value of the characteristic line is a request to start additional execution of Calibration. Note that in step S ⁇ b>607 , the control unit 300 transmits the existence probability of the object to the power receiving apparatus 101 without transmitting a request to add the received power value of the characteristic line to the power receiving apparatus 101 .
- control unit 300 After the transmission in step F719, the control unit 300 receives the received power value of the power receiving apparatus 101 from the power receiving apparatus 101 in step F720. In step F721, the control unit 300 functions as a correction unit, and corrects the characteristic line by extending the endpoints of the characteristic line based on the received power value.
- the power transmission device 102 can appropriately transmit information based on the existence probability of an object different from that of the power reception device 101 to the power reception device 101 .
- the power transmission device 102 that performs the foreign object detection process determines whether information indicating a request to start the process is included in the foreign object detection information according to the calculated foreign object existence probability, I tried to control.
- the foreign object detection information received by the power receiving apparatus 101 is not always composed of appropriate information. That is, although the presence probability of a foreign object is high, the power receiving apparatus 101 cannot control whether or not to receive foreign object detection information including a request to continue power transmission/reception processing. Therefore, in order to further improve the safety of the wireless power transmission system 100, it is desirable that the power receiving device 101 also perform appropriate control.
- the power receiving apparatus 101 determines whether or not to start the process requested by the foreign object detection information, and performs control.
- FIG. 10 is a flowchart showing a control method for the power receiving device 101 according to the second embodiment.
- the processing in FIG. 10 is implemented by executing a program read from the memory 209 by the control unit 200 of the power receiving apparatus 101, for example.
- the hardware in this case is realized by, for example, using a predetermined compiler to automatically generate a dedicated circuit using a gate array circuit such as FPGA from a program for realizing each processing step.
- 10 is executed when the power receiving apparatus 101 receives the foreign object detection information from the power transmitting apparatus 102, the process of FIG. 10 may be started by another trigger. .
- step S ⁇ b>1001 upon receiving the foreign object detection information from the power transmission device 102 , the control unit 200 determines whether the foreign object existence probability is greater than or equal to a first threshold based on the information indicating the foreign object existence probability included in the foreign object detection information. determine whether or not If the foreign object existence probability is greater than or equal to the first threshold (YES in S1001), control unit 200 proceeds to step S1002. move on.
- step S1002 the control unit 200 controls to stop power reception, and ends the processing in FIG. In this manner, the control unit 200 can suppress heat generation, ignition, and the like by immediately stopping power reception when the foreign object existence probability is equal to or greater than the first threshold.
- step S1003 the control unit 200 determines whether or not the probability of presence of foreign matter is equal to or greater than the second threshold. If the foreign object existence probability is greater than or equal to the second threshold (YES in S1003), control unit 200 proceeds to step S1004. move on.
- step S1004 the control unit 200 determines whether or not the received foreign object detection information includes information indicating a request to start re-executing Calibration. If information indicating a request to start re-executing Calibration is included (YES in S1004), control unit 200 proceeds to step S1005. If information indicating a request to start re-executing Calibration is not included (NO in S1004), control unit 200 proceeds to step S1006.
- step S1005 the control unit 200 controls the power transmission device 102 to start re-executing Calibration, and ends the processing in FIG.
- control unit 200 controls to lower the received power, and ends the processing in FIG.
- control unit 200 assumes that the power loss is increasing due to heat generation, misalignment, or the like, when the foreign object existence probability is not equal to or greater than the first threshold value, but is equal to or greater than the second threshold value. Control to re-execute Calibration or reduce received power. As a result, the wireless power transmission system 100 can suppress continuation of power transmission/reception at high output in a state where the characteristics of the calibration curve 1102 have changed.
- step S1007 the control unit 200 determines whether the received foreign object detection information includes information indicating a request to start processing. If information indicating a request to start processing is included (YES in S1007), control unit 200 proceeds to step S1008; if information indicating a request to start processing is not included (NO in S1007), The process of FIG. 10 ends.
- step S1008 the control unit 200 controls to start processing in response to the request to start the processing described above, and ends the processing in FIG.
- control unit 200 appropriately controls the start of the process according to the information indicating the probability of existence of a foreign object included in the received foreign object detection information, thereby realizing safer and more efficient wireless power transmission.
- System 100 can be implemented.
- Step F909 in FIG. 9 is a process for the power transmitting device 102 to derive a characteristic line indicating the relationship between the transmitted power value and the received power value.
- a characteristic line is a calibration curve 1102 .
- the control unit 200 functions as a transmitting unit, and transmits received power values Pr1 and Pr2 of the power receiving apparatus 101 when the power transmitting apparatus 102 sequentially transmits power of different transmitted power values Pt1 and Pt2 to the power receiving apparatus 101. Send to device 102 .
- the control unit 200 transmits the received power value of the power reception apparatus 101 to the power transmission apparatus 102 in step F917 of FIG.
- the control unit 200 functions as a receiving unit and receives from the power transmitting apparatus 102 the existence probability of an object different from the power receiving apparatus 101, which is calculated by the power transmitting apparatus 102 based on the received power value of the power receiving apparatus 101 and the characteristic line.
- the existence probability of an object is the existence probability of a foreign object.
- the control unit 200 when the existence probability of the object is equal to or higher than the second threshold (YES in S1003) and a request for re-derivation of the characteristic line is received from the power transmission device 102 (YES in S1004), the control unit 200 , the process proceeds to step S1005.
- the characteristic line re-derivation request is a calibration re-execution start request.
- Step S1005 is a process for the power transmitting apparatus 102 to derive a characteristic line indicating the relationship between the transmitted power value and the received power value.
- the control unit 200 functions as a transmitting unit and transmits to the power transmitting apparatus 102 the received power values of the power receiving apparatus 101 when the power transmitting apparatus 102 sequentially transmits power having different transmitted power values to the power receiving apparatus 101 .
- step S1006 the control unit 200 functions as a control unit and controls to lower the received power.
- step S1002 the control unit 200 functions as a control unit and controls to stop power reception.
- step S1008 the control unit 200 functions as a transmitting unit and transmits the received power value of the power receiving apparatus 101 to the power transmitting apparatus 102 (F720 in FIG. 7).
- the control unit 200 functions as a receiving unit and receives a foreign object detection signal including the existence probability of a foreign object from the power transmission device 102 .
- step S1001 of FIG. 10 when the presence probability of a foreign object is greater than the first threshold, the control unit 200 proceeds to step S1002 and controls to stop power reception.
- step S ⁇ b>1004 if the received foreign object detection signal includes information requesting processing related to reacquisition of the parameter (the received power value of the power receiving apparatus 101 ) used for determining the presence probability of a foreign object, the control unit 200 Proceed to S1005. In step S1005, the control unit 200 executes processing related to reacquisition of parameters.
- step S ⁇ b>1007 if the received foreign object detection signal includes information requesting processing related to additional acquisition of a parameter (the received power value of the power receiving apparatus 101 ) used to determine the presence probability of a foreign object, the control unit 200 Proceed to S1008. In step S1008, the control unit 200 executes processing related to additional parameter acquisition.
- step S1004 the control unit 200 determines that the presence probability of a foreign object is smaller than the first threshold value and larger than the second threshold value, and that the received foreign object detection signal indicates information requesting processing related to parameter reacquisition. If so, the process advances to step S1005. In addition, the control unit 200 determines that the presence probability of a foreign object is smaller than the first threshold value and larger than the second threshold value, and the received foreign object detection signal does not include information requesting processing related to parameter re-acquisition. If so, the process advances to step S1006 to control to lower the received power.
- step S1007 the control unit 200 determines that the presence probability of a foreign object is smaller than the first threshold value and smaller than the second threshold value, and that the received foreign object detection signal indicates information requesting processing related to additional parameter acquisition. If so, the process proceeds to step S1008. In step S1008, the control unit 200 executes processing related to additional parameter acquisition.
- the power receiving device 101 can appropriately receive information based on the existence probability of an object different from that of the power receiving device 101 from the power transmitting device 102 .
- the power transmission device 102 calculates the existence probability of a foreign object using the power loss method, which is a foreign object detection method based on power loss, as the foreign object detection process. may be calculated using For example, the power transmission device 102 may perform foreign object detection based on the Q value in the time domain that represents the attenuation state of the power transmission waveform, and calculate the presence probability of the foreign object.
- the power transmission device 102 may perform foreign object detection based on the Q value in the time domain that represents the attenuation state of the power transmission waveform, and calculate the presence probability of the foreign object.
- the existence probability of foreign matter can be calculated from the ratio, difference, or the like of the values.
- the power transmission device 102 may calculate the presence probability of a foreign object based on the amount of change in voltage value or current value per predetermined time, or may calculate the presence probability by combining two or more values. , but not limited to this. In this way, the power transmission device 102 can calculate the presence probability of a foreign object with higher accuracy by using another foreign object detection method or by combining a plurality of foreign object detection methods, thereby achieving safer wireless power transmission.
- System 100 can be implemented.
- the power transmitting apparatus 102 responds with ACK. Changed not to notify foreign object detection information. However, even in that case, the power transmitting device 102 may notify foreign object detection information. As a result, the power transmitting apparatus 102 can periodically notify information regarding foreign object detection even when the existence probability of a foreign object is low.
- the information indicating the request to start processing to be included in the foreign object detection information is a request premised on the continuation of power transmission and reception, such as additional execution or re-execution of calibration. It may be a request to suppress or stop power reception.
- the power transmitting apparatus 102 transmits foreign object detection information including information indicating the request to the power receiving apparatus 101 .
- the power transmission device 102 can more reliably suppress or stop power transmission and reception when the presence probability of a foreign object is high, and can realize a safer wireless power transmission system 100 .
- the power transmission device 102 notifies the foreign object detection information after performing the foreign object detection process, but may notify at another timing. At this time, if the foreign object detection process is not performed or the existence probability of the foreign object is unknown, the power transmission device 102 sets the information indicating the existence probability of the foreign object to a specific value (for example, 0) to detect the foreign object. Information may be notified. Also, the power transmitting apparatus 102 may notify the information indicating the request to start processing as a specific value (for example, 0xFF), but is not limited to this.
- a specific value for example, 0xFF
- the power receiving apparatus 101 when the power receiving apparatus 101 receives foreign object detection information indicating that the foreign object detection process has not been performed or that the presence probability of a foreign object is unknown, the power receiving apparatus 101 detects the received power, the transmission output, or the GP may be controlled so as not to rise above a predetermined value (or to be lowered to a predetermined value). As a result, the power receiving apparatus 101 can suppress high-power power transmission/reception in a state where the foreign object detection process is not performed, that is, in a state in which the possibility of the presence of a foreign object cannot be denied.
- the power transmitting apparatus 102 transmits information indicating re-execution of calibration when the probability of existence of a foreign object is equal to or greater than the second threshold, and a request to start additional execution of calibration when the probability of existence of a foreign object is less than the second threshold.
- information is included in the foreign object detection information.
- the power transmitting device 102 may include opposite information in the foreign object detection information.
- the power receiving device and power transmitting device can have the function of executing applications other than wireless charging.
- An example of a power receiving device is an information processing terminal such as a smart phone, and an example of a power transmitting device is an accessory device for charging the information processing terminal.
- an information terminal device has a display unit (display) that displays information to a user, and is supplied with power received from a power receiving coil (antenna). Further, the electric power received from the power receiving coil is accumulated in a power storage unit (battery), and electric power is supplied from the battery to the display unit.
- the power receiving device may have a communication unit that communicates with another device different from the power transmitting device.
- the communication unit may support communication standards such as NFC (Near field communication) and fifth generation mobile communication system (5G). Further, in this case, the communication unit may perform communication by supplying power from the battery to the communication unit.
- the power receiving device may be a tablet terminal, a storage device such as a hard disk device and a memory device, or an information processing device such as a personal computer (PC). Also, the power receiving device may be, for example, an imaging device (camera, video camera, etc.).
- the power receiving device may be an image input device such as a scanner, or may be an image output device such as a printer, copier, or projector. Also, the power receiving device may be a robot, a medical device, or the like.
- the power transmission device can be a device for charging the device described above.
- the power transmission device may be a smartphone.
- the power receiving device may be another smartphone or wireless earphones.
- the power receiving device in this embodiment may be a vehicle such as an automobile or an automated guided vehicle (AGV: Automated Guided Vehicle).
- an automobile which is a power receiving device, may receive power from a charger (power transmitting device) via a power transmitting antenna installed in a parking lot.
- a vehicle which is a power receiving device, may receive power from a charger (power transmitting device) via a power transmitting coil (antenna) embedded in a road or running path.
- the received power is supplied to the battery.
- the power of the battery may be supplied to the driving unit (motor, electric unit) that drives the wheels, or may be used to drive sensors used for driving assistance or to drive the communication unit that communicates with external devices. good.
- the power receiving device may include a battery, a motor or sensor driven by the received power, and a communication unit that communicates with devices other than the power transmitting device, in addition to the wheels.
- the power receiving device may have a housing section that houses a person.
- sensors include sensors used to measure the distance between vehicles and the distance to other obstacles.
- the communication unit may be compatible with, for example, the Global Positioning System (Global Positioning Satellite, GPS).
- the communication unit may support a communication standard such as the fifth generation mobile communication system (5G).
- the vehicle may be a bicycle or a motorcycle.
- the power receiving device is not limited to a vehicle, and may be a moving object, an flying object, or the like having a driving unit that is driven using electric power stored in a battery.
- the power receiving device in this embodiment may be an electric tool, a home appliance, or the like.
- These devices which are power receiving devices, may have a battery as well as a motor driven by received power stored in the battery. Also, these devices may have notification means for notifying the remaining amount of the battery. Also, these devices may have a communication unit that communicates with another device different from the power transmission device.
- the communication unit may support communication standards such as NFC and the fifth generation mobile communication system (5G).
- the power transmission device in the present embodiment may be an in-vehicle charger that transmits power to portable information terminal devices such as smartphones and tablets compatible with wireless power transmission inside the vehicle.
- an on-board charger may be provided anywhere in the vehicle.
- the in-vehicle charger may be installed in the console of the automobile, or may be installed in the instrument panel (instrument panel, dashboard), between the seats of passengers, on the ceiling, or on the door. However, it should not be installed in a place that interferes with driving.
- the power transmission device has been described as an example of an in-vehicle charger, such a charger is not limited to being arranged in a vehicle, and may be installed in a transport machine such as a train, an aircraft, or a ship. Chargers in this case may also be installed between passenger seats, on the ceiling, or on the door.
- a vehicle such as an automobile equipped with an in-vehicle charger may be the power transmission device.
- the power transmission device has wheels and a battery, and uses the power of the battery to supply power to the power reception device through the power transmission circuit unit and the power transmission coil (antenna).
- the present disclosure provides a program that implements one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device reads and executes the program. It can also be realized by processing to It can also be implemented by a circuit (for example, ASIC) that implements one or more functions.
- a circuit for example, ASIC
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Abstract
Description
以下、図面を参照して実施形態を詳しく説明する。なお、以下の実施形態は特許請求の範囲を限定するものでない。実施形態には複数の特徴が記載されているが、これらの複数の特徴の全てが必須のものとは限らず、また、複数の特徴は任意に組み合わせられてもよい。さらに、図面においては、同一若しくは同様の構成に同一の参照番号を付し、重複した説明は省略する。
図1は、第1の実施形態に係る無線電力伝送システム100の構成例を示す図である。無線電力伝送システム100は、非接触充電システムであり、一例として、受電装置101と送電装置102と充電台103を有する。受電装置101は、送電装置102から受電して内蔵バッテリに充電を行う電子機器である。送電装置102は、充電台103に載置された受電装置101に対して無線で送電する電子機器である。範囲104は、受電装置101が、送電装置102から送電された電力を受電可能な範囲を示している。なお、受電装置101と送電装置102は、非接触充電以外のアプリケーションを実行する機能を有してもよい。なお、受電装置101は、一例として、スマートフォンであり、送電装置102は、一例として、そのスマートフォンを充電するためのアクセサリ機器である。
続いて、本実施形態に係る送電装置102および受電装置101の構成について説明する。なお、以下で説明する構成は一例に過ぎず、説明される構成の一部(場合によっては全部)は、他の同様の機能を果たす他の構成と置き換えられまたは省略されてもよく、さらなる構成が説明される構成に追加されてもよい。さらに、以下の説明で示される1つのブロックが複数のブロックに分割されてもよいし、複数のブロックが1つのブロックに統合されてもよい。
図5は、送電装置102の制御方法を示すフローチャートである。図5の処理は、例えば送電装置102の制御部300がメモリ307から読み出したプログラムを実行することによって、実現される。なお、以下の処理の少なくとも一部がハードウェアによって実現されてもよい。この場合のハードウェアは、例えば、所定のコンパイラを用いて、各処理ステップを実現するためのプログラムからFPGA等のゲートアレイ回路を用いた専用回路を自動的に生成することによって実現可能である。また、図5の処理は、送電装置102の電源がオンとされたことに応じて、送電装置102のユーザが無線電力伝送アプリケーションの開始指示を入力したことに応じて、または、送電装置102が商用電源に接続され電力供給を受けていることに応じて、実行される。また、図5の処理は、他の契機によって開始されてもよい。
送電装置102が上述の処理を実行する場合の動作シーケンスについて、いくつかの状況を想定して説明する。なお、初期状態として、受電装置101は、送電装置102上に載置されておらず、送電装置102は、受電装置101が要求するGPでの送電を実行可能な程度の十分な送電能力を有しているものとする。
まず、第1の処理例について説明する。第1の処理例では、最初のNegotiationフェーズでGPが5ワットに決定され、送電が開始される。そして、送電開始後、Negotiationフェーズの再実行によりGPが15ワットに再決定される。再決定されたGPに従って受電装置101における受電電力値が増加し、当該受電電力値がCalibrationカーブ1102の最大の受電電力値(すなわち、5ワット)に対して所定割合より大きくなる。このとき、送電装置102は、異物の存在確率を示す情報に加えて、Calibrationの追加実行の開始要求を示す情報を含む異物検出情報を受電装置101に送信する。例えば、Calibrationの追加実行の開始要求を行うと判定する所定割合は、20%であるが、一例に過ぎず、別の値であってもよい。
次に、第2の処理例について説明する。第2の処理例では、最初のNegotiationフェーズでGPが5ワットに決定され、送電が開始される。そして、送電開始後、Negotiationフェーズの再実行によりGPが15ワットに再決定され、受電装置101における受電電力値が増加していく中で、異物が混入する。その後、受電装置101の受電電力値がCalibrationカーブ1102の最大の受電電力値(すなわち、5ワット)に対して所定割合より大きくなる。このとき、送電装置102は、異物検出処理の結果、異物の存在確率が第1の閾値以上であるため、Calibrationの追加実行の開始要求を異物検出情報に含めず受電装置101に送信する。なお、第1の閾値は75%であり、Calibrationの追加実行の開始要求を行うと判定する所定割合は20%であるものとして説明を行うが、一例に過ぎず、別の値であってもよい。
続いて、第3の処理例について説明する。第3の処理例では、最初のNegotiationフェーズでGPが15ワットに決定され、送電が開始される。そして、送電開始後、異物の存在確率が第1の閾値以上ではなく、第2の閾値以上である状態が、所定時間以上継続する。このとき、送電装置102は、発熱や受電装置101の位置ずれ等によりCalibrationカーブ1102の特性が変化したと判定する。そして、送電装置102は、異物の存在確率を示す情報に加えて、Calibrationの再実行の開始要求を示す情報を含む異物検出情報を受電装置101に送信する。なお、第1の閾値は75%であり、第2の閾値は25%であるものとして説明を行うが、一例に過ぎず、第1の閾値>第2の閾値となる別の値であってもよいし、第1の閾値が第2の閾値と同一であってもよい。
第1の実施形態では、異物検出処理を実施する主体である送電装置102が、算出した異物の存在確率に応じて異物検出情報に処理の開始要求を示す情報を含めるか否かを判定し、制御を行うようにした。しかしながら、受電装置101が受信する異物検出情報は、全て適切な情報で構成されているとは限らない。すなわち、異物の存在確率は高いが、受電装置101は、送受電処理の継続を指示するような要求を含む異物検出情報を受信するか否かを制御できない。したがって、無線電力伝送システム100の安全性をより向上させるためには、受電装置101も適切な制御を行うことが望ましい。第2の実施形態では、その一例として、受電装置101は、異物検出情報により要求された処理を開始するか否かを判定し、制御を行う。
図10は、第2の実施形態に係る受電装置101の制御方法を示すフローチャートである。図10の処理は、例えば受電装置101の制御部200がメモリ209から読み出したプログラムを実行することによって、実現される。なお、以下の処理の少なくとも一部は、ハードウェアによって実現されてもよい。この場合のハードウェアは、例えば、所定のコンパイラを用いて、各処理ステップを実現するためのプログラムからFPGA等のゲートアレイ回路を用いた専用回路を自動的に生成することによって実現される。また、図10の処理は、受電装置101が送電装置102から異物検出情報を受信したことに応じて実行されるが、これに限らず、他の契機によって図10の処理が開始されてもよい。
第1および第2の実施形態では、送電装置102は、異物検出処理として電力損失に基づいた異物検出手法であるパワーロス手法を用いて異物の存在確率を算出するようにしたが、他の手法を用いて算出してもよい。例えば、送電装置102は、送電波形の減衰状態を表す時間領域におけるQ値に基づいて異物検出を行い、異物の存在確率を算出してもよい。送電装置102と受電装置101の近傍に異物が存在する場合には、当該異物によってエネルギー損失が発生してQ値が低下するため、送電装置102は、異物が存在する場合と存在しない場合のQ値の比率や差分等から、異物の存在確率を算出することができる。また、送電装置102は、所定時間当たりの電圧値や電流値の変化量に基づいて異物の存在確率を算出してもよいし、2つ以上の値を組み合わせて存在確率を算出してもよく、これに限るものではない。このように、送電装置102は、他の異物検出手法を用いたり、複数の異物検出手法を組み合わせることで、より高い精度で異物の存在確率を算出することが可能となり、より安全な無線電力伝送システム100を実現することができる。
Claims (14)
- 受電装置に無線送電する送電装置であって、
前記受電装置とは異なる物体の存在確率を決定するために用いるパラメータを取得する取得手段と、
前記取得手段により取得されるパラメータに基づいて、前記物体の存在確率を決定する決定手段と、
前記決定手段により決定された前記物体の存在確率に基づいて、前記物体の存在確率を特定するための情報を含む信号を前記受電装置に送信する送信手段とを有し、
前記送信手段は、前記決定手段により決定された前記物体の存在確率が閾値より小さい場合、前記信号に前記パラメータの再取得に係る処理を要求する情報を含めて、前記信号を送信し、前記決定手段により決定された前記物体の存在確率が閾値より大きい場合、前記信号に前記パラメータの再取得に係る処理を要求する情報を含めずに前記信号を送信することを特徴とする送電装置。 - 前記送信手段は、
前記決定手段により決定された前記物体の存在確率が第1の閾値より大きい場合、前記信号に前記パラメータの再取得に係る処理を要求する情報を含めずに前記信号を送信し、
前記決定手段により決定された前記物体の存在確率が前記第1の閾値より小さく、且つ、第2の閾値より大きい場合、前記信号に前記パラメータの再取得に係る処理を要求する情報を含めて、前記信号を送信し、
前記決定手段により決定された前記物体の存在確率が前記第1の閾値より小さく、且つ、前記第2の閾値より小さい場合、前記パラメータに応じて、前記信号に前記パラメータの追加取得に係る処理を要求する情報を含めて、前記信号を送信し
前記第2の閾値は、前記第1の閾値より小さいことを特徴とする請求項1に記載の送電装置。 - 前記パラメータは、前記受電装置の受電電力値であり、
前記送信手段は、
前記決定手段により決定された前記物体の存在確率が前記第1の閾値より小さく、且つ、前記第2の閾値より小さく、且つ、前記受電装置の受電電力値が第1の受電電力値より大きい場合、前記信号に前記パラメータの追加取得に係る処理を要求する情報を含めて、
前記信号を送信し、
前記決定手段により決定された前記物体の存在確率が前記第1の閾値より小さく、且つ、前記第2の閾値より小さく、且つ、前記受電装置の受電電力値が前記第1の受電電力値より小さい場合、前記信号を送信しないことを特徴とする請求項2に記載の送電装置。 - 前記送信手段は、前記決定手段により決定された前記物体の存在確率が前記第1の閾値より小さく、且つ、前記第2の閾値より大きい状態が所定時間継続した場合、前記信号に前記パラメータの再取得に係る処理を要求する情報を含めて、前記信号を送信することを特徴とする請求項2又は3に記載の送電装置。
- 前記パラメータは、前記受電装置の受電電力値であることを特徴とする請求項1~4のいずれか1項に記載の送電装置。
- 送電装置から無線受電する受電装置であって、
前記受電装置とは異なる物体の存在確率を含む信号を前記送電装置から受信する受信手段と、
前記物体の存在確率が第1の閾値より大きい場合には、受電を停止するように制御し、
前記物体の存在確率が前記第1の閾値より小さく、且つ、前記受信した信号が、前記物体の存在確率を決定するために用いるパラメータの再取得に係る処理を要求する情報を含む場合、前記パラメータの再取得に係る処理を実行する制御手段と
を有することを特徴とする受電装置。 - 前記制御手段は、
前記物体の存在確率が前記第1の閾値より小さく、且つ、第2の閾値より大きく、且つ、前記受信した信号が前記パラメータの再取得に係る処理を要求する情報を含む場合、前記パラメータの再取得に係る処理を実行し、
前記物体の存在確率が前記第1の閾値より小さく、且つ、前記第2の閾値より大きく、
且つ、前記受信した信号が前記パラメータの再取得に係る処理を要求する情報を含まない場合、受電電力を下げるように制御し、
前記第2の閾値は、前記第1の閾値より小さいことを特徴とする請求項6に記載の受電装置。 - 前記制御手段は、前記物体の存在確率が前記第1の閾値より小さく、且つ、第2の閾値より小さく、且つ、前記受信した信号が前記パラメータの追加取得に係る処理を要求する情報を含む場合、前記パラメータの追加取得に係る処理を実行することを特徴とする請求項7に記載の受電装置。
- 前記パラメータは、前記受電装置の受電電力値であることを特徴とする請求項6~8のいずれか1項に記載の受電装置。
- 請求項1~5のいずれか1項に記載の送電装置と、
請求項6~9のいずれか1項に記載の受電装置と
を有することを特徴とする無線電力伝送システム。 - 受電装置に無線送電する送電装置の制御方法であって、
前記受電装置とは異なる物体の存在確率を決定するために用いるパラメータを取得する取得ステップと、
前記取得ステップで取得されるパラメータに基づいて、前記物体の存在確率を決定する決定ステップと、
前記決定ステップで決定された前記物体の存在確率に基づいて、前記物体の存在確率を特定するための情報を含む信号を前記受電装置に送信する送信ステップとを有し、
前記送信ステップでは、前記決定ステップで決定された前記物体の存在確率が閾値より小さい場合、前記信号に前記パラメータの再取得に係る処理を要求する情報を含めて、前記信号を送信し、前記決定ステップで決定された前記物体の存在確率が閾値より大きい場合、前記信号に前記パラメータの再取得に係る処理を要求する情報を含めずに前記信号を送信することを特徴とする送電装置の制御方法。 - 送電装置から無線受電する受電装置の制御方法であって、
前記受電装置とは異なる物体の存在確率を含む信号を前記送電装置から受信する受信ステップと、
前記物体の存在確率が第1の閾値より大きい場合には、受電を停止するように制御し、
前記物体の存在確率が前記第1の閾値より小さく、且つ、前記受信した信号が、前記物体の存在確率を決定するために用いるパラメータの再取得に係る処理を要求する情報を含む場合、前記パラメータの再取得に係る処理を実行する制御ステップと
を有することを特徴とする受電装置の制御方法。 - コンピュータを、請求項1~5のいずれか1項に記載された送電装置の各手段として機能させるためのプログラム。
- コンピュータを、請求項6~9のいずれか1項に記載された受電装置の各手段として機能させるためのプログラム。
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JP2015056959A (ja) | 2013-09-11 | 2015-03-23 | ローム株式会社 | ワイヤレス受電装置、その制御回路および制御方法 |
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