JP2018074684A - Power supply apparatus, method for controlling power supply apparatus, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of a conventional power supply apparatus in which erroneous detection occasionally occurs when the load of a power supply target apparatus fluctuates.SOLUTION: A power supply apparatus for contactlessly supplying power to a power reception apparatus through an antenna comprises: generation means generating supply power output from the antenna; matching means connected between the antenna and the generation means; detection means detecting the change of the matching state of the matching means; and determination means determining whether a foreign matter is present or not in a predetermined range. The determination means determines the presence/absence of a foreign matter using a variation value per unit time of the matching state detected by the detection means, or it determines the presence/absence of a foreign matter using the variation value and a continuance period in which the variation continues since the variation occurs and/or a variation amount during the continuance period.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power supply device that supplies power without contact.

  In recent years, a non-contact including a power supply device having a primary coil as an antenna for outputting power in a non-contact manner and an electronic device having a secondary coil as an antenna for receiving power supplied from the power supply device in a non-contact manner Power supply systems are known. In such a system, there is known a technique for detecting an object as a foreign object when an unintentional object comes between a primary coil of a power supply device and a secondary coil of an electronic device (Patent Document 1). Here, the foreign matter is a metal or an electronic device that does not support power reception. Foreign matter detection is performed in order to prevent unintentional electric power from being applied to metal objects and electronic devices that do not support power reception to generate heat and break down.

JP2013-126307A

  In the prior art disclosed in Patent Document 1 described above, impedance is calculated based on the current and voltage flowing through the antenna, and the calculated impedance value is compared with a reference impedance value to determine the presence or absence of a foreign object. It was.

  However, in this case, even if the load of the electronic device to be fed changes, the impedance at the antenna end may change and may be erroneously detected as a foreign object. Therefore, an object of the present invention is to reduce false detection of foreign object determination when the load of a power supply target device changes.

  In order to achieve the above object, a power supply device according to the present invention detects a change in a matching state of a generation unit that generates power to be supplied from an antenna, a matching unit that is connected between the antenna and the generation unit, and a matching unit. And determining means for determining whether or not the detection means and the foreign matter are within a predetermined range, wherein the determination means determines the presence or absence of foreign matter using a fluctuation value per unit time of the alignment state detected by the detection means. Alternatively, the presence or absence of a foreign substance is determined using the fluctuation value and a duration during which the fluctuation lasts and / or a fluctuation amount during the duration.

  ADVANTAGE OF THE INVENTION According to this invention, the misdetection of the foreign material determination when the load of the electric power feeding object apparatus changes can be reduced.

The figure for demonstrating the structure of the system in 1st Embodiment. Block diagram of a system in the first embodiment The figure which showed the control flow of the foreign material detection process in 1st Embodiment. The figure which showed the graph when not determining with the foreign material in 1st Embodiment The figure which showed the control flow of the foreign material detection process in 2nd Embodiment.

  Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments, and various modifications and changes can be made within the scope of the gist.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.

<System configuration>
As shown in FIG. 1, the system configuration according to the present embodiment includes an electronic device 200 and a power supply device 100 that communicates power supply and communication to the electronic device 200 in a contactless manner.

  When the distance between the power supply device 100 and the electronic device 200 is within a predetermined range, the power supply device 100 having the power supply antenna 108 communicates in a non-contact manner via the power supply antenna 108 so that the electronic device 200 can receive power. Judge whether or not the device is correct. When the power supply device 100 determines that the electronic device 200 is a device that can receive power, the power supply device 100 outputs power for power supply via the power supply antenna 108 and supplies the power to the electronic device 200.

  The electronic device 200 having the power receiving antenna 201 receives the power output from the power feeding device 100 via the power receiving antenna 201 in a non-contact manner.

  When the distance between the power supply device 100 and the electronic device 200 does not exist within a predetermined range, the power supply device 100 keeps a weak power constant in order to detect whether the electronic device 200 is within the predetermined range. Output at intervals.

  Note that the predetermined range is a range in which the electronic device 200 can perform communication using the power supplied from the power supply device 100.

  The electronic device 200 may be an electronic device that operates with electric power supplied from the secondary battery 210. For example, it may be an imaging device such as a digital still camera, a mobile phone with a camera, or a digital video camera, or a playback device such as a player that plays back audio data or video data. Further, the electronic device 200 may be a mouse or a speaker that operates with only the received power without a secondary battery.

  Here, FIG. 1 is a diagram when a foreign object approaches the present system configured by the power supply device 100 and the power reception device 200, particularly the power supply device 100. When the foreign object comes close to the power supply device 100 in this way, the power supply device 100 detects the foreign object at least by the foreign object detection circuit 116 and weakens or stops the power supply output so that the supply power is transmitted to the foreign object.

<About the power supply device 100>
FIG. 2 is a diagram showing a block configuration of the present system having the power supply device 100 and the electronic device 200.

  As shown in FIG. 2, the power supply device 100 includes an oscillator 101, a power transmission circuit 102, a matching detection circuit 103, a matching circuit 104, a CPU 105, a modem circuit 106, a timer 107, a power supply antenna 108, a ROM 109, and a RAM 110. Furthermore, a conversion unit 111, a recording unit 112, a display unit 113, an operation unit 114, a communication unit 115, and a foreign object detection circuit 116 are included. Furthermore, the recording unit includes a recording medium 112a.

  The oscillator 101 is a crystal resonator, a crystal oscillator, or the like, and oscillates at a predetermined frequency to generate a high frequency signal. The high frequency signal is supplied to the power transmission unit 102, amplified based on the power supplied from the AC power supply via the conversion unit 111, and becomes high frequency power to be supplied to the electronic device 200.

  The power transmission circuit 102 generates power to be supplied to the electronic device 200 via the power feeding antenna 108 according to the power supplied from the conversion unit 111 and the frequency oscillated by the oscillator 101. The power transmission circuit 102 includes an FET or the like inside, and generates power to be supplied to the electronic device 200 according to the frequency oscillated by the oscillator 101. The power to be generated is controlled, for example, by controlling the current flowing between the source and drain terminals of the FET when it has an FET inside. The power generated by the power transmission circuit 102 is supplied to the power feeding antenna 108 via the matching detection circuit 103 and the matching circuit 104.

  In addition, the power generated by the power transmission circuit 102 includes a first power and a second power. The first power is power for the power supply device 100 to transmit a command for controlling the electronic device 200 to the electronic device 200. The second power is higher than the first power. For example, the first power is 1 W or less, and the second power is 1 W to 10 W.

  Note that when the power supply device 100 supplies the first power to the electronic device 200, the power supply device 100 can transmit a command to the electronic device 200. However, when the power supply device 100 supplies the second power to the electronic device 200, the power supply device 100 cannot transmit a command to the electronic device 200.

  The first power is power set by the CPU 105 so that the power supply device 100 can transmit a command to any device other than the electronic device 200.

  The CPU 105 controls the power transmission circuit 102 so that the power supplied to the electronic device 200 is switched to one of the first power and the second power.

  The matching detection circuit 103 measures the voltage of the traveling wave of the power generated in the power transmission circuit 102 and the reflected wave from the feeding antenna 108, and detects the voltage standing wave ratio. Here, the voltage standing wave ratio (VSWR: Voltage Standing Wave Ratio) is a numerical value indicating the voltage relationship between the traveling wave and the reflected wave,

It is represented by

  However,

(Z: antenna side impedance, Zo: matching detection circuit side impedance, Vf: traveling wave amplitude voltage, Vr: reflected wave amplitude voltage)

It is.

  By detecting this VSWR, it can be determined whether or not impedance matching is achieved. When impedance matching is achieved, the amplitude voltage of the reflected wave is zero, and VSWR is 1 when Z = Zo.

  The matching circuit 104 includes elements such as a variable capacitor, a variable coil, and a variable resistor. The matching circuit 104 performs impedance matching between the impedance on the matching detection circuit 103 side and the feeding antenna 108 according to these elements. In addition, the matching circuit 104 does not have to include all of a variable capacitor, a variable coil, and a variable resistor.

  The matching circuit 104 is also a resonance circuit for performing resonance between the power feeding antenna 108 and the power receiving antenna 201 of the electronic device 200 to be fed selected by the CPU 105 in accordance with the frequency oscillated by the oscillator 101. is there.

  Note that the resonance frequency f is a frequency at which the power supply device 100 and the electronic device 200 resonate. Hereinafter, a frequency at which the power supply device 100 and the electronic device 200 resonate is referred to as a “resonance frequency f”.

  The following formula (2) is a formula showing the relationship among the resonance frequency f, the inductance L, and the capacitance C. L is the inductance of the matching circuit 104, and C is the capacitance of the matching circuit 104.

  The inductance of the matching circuit 104 is an inductance that includes an inductance component such as the feeding antenna 108 in addition to the variable coil of the matching circuit 104. Similarly, the capacitance is a capacitance including a capacitance component such as the antenna 108 other than the variable capacitor of the matching circuit 104.

  The matching circuit 104 may further include a capacitor in addition to the variable capacitor, may further include a coil in addition to the variable coil, and may further include a resistor in addition to the variable resistor.

  The CPU 105 controls the values of the variable capacitor and the variable coil of the matching circuit 104 so that the matching detection circuit 103 side and the feeding antenna 108 side are in a resonance state at the frequency oscillated by the oscillator 101.

  The resonance frequency f may be a commercial frequency of 50/60 Hz, 10 to several hundreds of kHz, or a frequency of around 10 MHz.

  When the AC power supply and the power supply device 100 are connected, the CPU 105 controls each unit of the power supply device 100 with the power supplied from the AC power supply via the conversion unit 111. Further, the CPU 105 controls the operation of each unit of the power supply apparatus 100 by executing a computer program recorded in the ROM 109. The CPU 105 controls the power supplied to the electronic device 200 by controlling the power transmission circuit 102. The CPU 105 transmits a command to the electronic device 200 by controlling the modulation / demodulation circuit 106.

  The modem circuit 106 modulates the power generated by the power transmission circuit 102 in accordance with a predetermined protocol in order to transmit a command for controlling the electronic device 200 to the electronic device 200. The predetermined protocol is a communication protocol based on ISO / IEC 18092 standard such as RFID (Radio Frequency IDentification). The power generated by the power transmission circuit 102 is converted into a pulse signal by the modulation / demodulation circuit 106 as a command for communicating with the electronic device 200, and transmitted to the electronic device 200 via the power supply antenna 108. The predetermined protocol may be a communication protocol that is compatible with the NFC (Near Field Communication) standard.

  The pulse signal transmitted to the electronic device 200 is detected by the electronic device 200 as bit data including “1” information and “0” information. The command includes identification information for identifying a destination, a command code indicating an operation instructed by the command, and the like. Note that the CPU 105 can transmit the command only to the electronic device 200 by controlling the modulation / demodulation circuit 106 so as to change the identification information included in the command. The CPU 105 can also transmit the command to the electronic device 200 and devices other than the electronic device 200 by controlling the modulation / demodulation circuit 106 so as to change the identification information included in the command.

  The modem circuit 106 converts the power generated by the power transmission circuit 102 into a pulse signal by ASK (Amplitude Shift Keying) modulation using amplitude displacement. ASK modulation is modulation using amplitude displacement, and is used for communication between an IC card and a card reader that performs non-contact communication with the IC card.

  The modem circuit 106 is changed to a pulse signal by changing the amplitude of the power generated by the power transmission circuit 102 by switching an analog multiplier and a load resistor included in the modem circuit 106. The pulse signal changed by the modem circuit 106 is supplied to the power feeding antenna 108 and transmitted to the electronic device 200 as a command.

  The modulation / demodulation circuit 106 modulates data encoded by the CPU 105 according to a predetermined encoding method.

  The modem circuit 106 can demodulate a response from the electronic device 200 to the command transmitted to the electronic device 200 in accordance with a change in the current flowing through the power feeding antenna 108 detected by the matching circuit 104. As a result, the modem circuit 106 can receive a response to the command transmitted from the electronic device 200 to the electronic device 200 by the load modulation method. The modem circuit 106 transmits a command to the electronic device 200 in accordance with an instruction from the CPU 105. Further, when receiving a response from the electronic device 200, the modem circuit 106 demodulates the received response and transmits it to the CPU 105.

  The timer 107 measures the current time and the time related to operations and processes performed in each unit. A threshold for the time measured by the timer 107 is recorded in advance in the ROM 109.

  The power feeding antenna 108 is an antenna for outputting the power generated by the power transmission circuit 102 to the outside.

  The power supply device 100 supplies power or transmits a command to the electronic device 200 via the power supply antenna 108. The power supply device 100 receives a command from the electronic device 200 via the power supply antenna 108, a response corresponding to the command transmitted to the electronic device 200, and information transmitted from the electronic device 200.

  The ROM 109 records information such as a computer program for controlling the operation of each unit of the power supply apparatus 100 and parameters relating to the operation of each unit. The ROM 109 records video data to be displayed on the display unit 113.

  The RAM 110 is a rewritable non-volatile memory that temporarily stores a computer program for controlling the operation of each unit of the power supply device 100, information on parameters regarding the operation of each unit, information received from the electronic device 200 by the modem circuit 106, and the like. Record.

  When the AC power source and the power supply apparatus 100 are connected, the conversion unit 111 converts the AC voltage supplied from the AC power source into a DC voltage, converts the converted DC voltage into an appropriate voltage value, and converts the CPU 105 and power The power is supplied to the entire power supply apparatus 100 including the transmission circuit 102.

  The recording unit 112 records data such as video data and audio data received by the communication unit 115 in the recording medium 110a.

  The recording unit 112 can also read data such as video data and audio data from the recording medium 110 a and supply the data to the RAM 110, the communication unit 115, and the display unit 113.

  Note that the recording medium 110 a may be a hard disk, a memory card, or the like, and may be a built-in power supply device 100 or an external recording medium that is detachable from the power supply device 100.

  The display unit 113 displays video data read from the recording medium 110 a by the recording unit 112, video data supplied from the RAM 110, video data supplied from the ROM 109, and video data supplied from the communication unit 115. indicate. The display unit 113 can also display video data read from the recording medium 110a, icons and menu screens recorded in advance in the ROM 109, and the like.

  The operation unit 114 provides a user interface for operating the power supply apparatus 100. The operation unit 114 includes a power button for operating the power supply device 100, a mode switching button for switching the operation mode of the power supply device 100, a setting change button for changing settings of the power supply device 100, and the like. And a touch panel. The CPU 105 controls the power supply apparatus 100 in accordance with a user instruction input via the operation unit 114. Note that the operation unit 114 may be an object that controls the power supply apparatus 100 according to a remote control signal received from a remote controller (not shown).

  The communication unit 115 transmits video data and audio data supplied from any one of the RAM 110 and the recording medium 110 a to the electronic device 200. In addition, the communication unit 115 receives video data and audio data transmitted from the electronic device 200 to the power supply device 100.

  For example, the communication unit 115 may perform communication according to an interface such as USB or HDMI (registered trademark) (High-Definition Multimedia Interface). The communication unit 115 is an object that may perform communication based on the non-contact communication method. For example, the communication unit 115 may perform wireless communication according to the 802.11a, b, g, and n standards defined in the wireless LAN standard. The communication unit 115 may transmit and receive video data and audio data by modulating the signal into a signal compliant with the wireless LAN standard.

  Note that the communication unit 115 receives video data or audio data from the electronic device 200, or receives video data or audio data even when a command is transmitted from the modulation / demodulation circuit 106 to the electronic device 200 via the power feeding antenna 108. Data can be transmitted to the electronic device 200. Further, the communication unit 115 receives video data and audio data from the electronic device 200 even when a response corresponding to the command is received from the electronic device 200 via the power feeding antenna 108 by the modulation / demodulation circuit 106. 200.

  The foreign object detection circuit 116 is a circuit for detecting an object that is not a power supply target device as a foreign object. Here, the foreign matter is an electronic device, metal, ID card, or the like that is out of power feeding symmetry, and is an object that is unintentionally affected by the power feeding power due to the non-contact power feeding power from the power feeding device 100. The foreign object detection circuit 116 is connected to the matching detection circuit 103. For example, the standing wave ratio and the reflected wave signal level are transmitted from the matching detection circuit to the CPU 105 as a foreign object detection signal. In addition, the foreign object detection circuit 116 may be connected to the power supply antenna 108, and a current or voltage flowing through the power supply antenna 108 may be transmitted to the CPU 105 as a foreign object detection signal. Further, the foreign object detection circuit 116 may be connected to the power transmission circuit 102 and sends the output voltage and output current from the power transmission circuit 102 and the input voltage and input current to the transmission transmission circuit 102 to the CPU 105 as a foreign object detection signal. May be.

  The CPU 1105 determines the presence or absence of foreign matter based on the foreign matter detection signal received from the foreign matter detection circuit 116. If the CPU 1105 determines that there is a foreign matter, the CPU 1105 controls the power transmission circuit 102 to weaken the power supply output output through the antenna 108. Or stop.

  For example, the CPU 105 may determine the presence or absence of a foreign object from a change in the standing wave ratio, may determine the presence or absence of a foreign object from a change in the input / output current voltage of the power transmission circuit 102, or a power feeding antenna. The presence or absence of foreign matter may be determined from the current voltage 108.

  The power supply apparatus 100 may further include a speaker unit (not shown). The speaker unit (not shown) is one of audio data read from the recording medium 110a by the recording unit 112, audio data supplied from the ROM 109, audio data supplied from the RAM 110, and audio data supplied from the communication unit 115. Is an object to be output.

  When the power supply device 100 supplies power to the electronic device 200 via the power supply antenna 108, the power transmission circuit 102, the matching circuit 104, the modulation / demodulation circuit 106, and the power supply antenna 108 generate the first power and the second power. Either one is output to the electronic device 200.

  When the power supply device 100 transmits a command to the electronic device 200 via the power supply antenna 108, the first power and the command are transmitted by the power transmission circuit 102, the matching circuit 104, the modulation / demodulation circuit 106, and the power supply antenna 108. Supplied to the device 200.

  When the power supply device 100 transmits at least one of video data and audio data to the electronic device 200, at least one of the video data and audio data is transmitted to the electronic device 200 by the communication unit 115.

  When the power supply device 100 receives at least one of video data and audio data from the electronic device 200, the communication unit 115 receives at least one of the video data and audio data from the electronic device 200.

  Even when the communication unit 115 transmits at least one of video data and audio data to the electronic device 200, the power supply device 100 sends a command or information to the electronic device 200 via the power supply antenna 108. Can be sent. Even when the communication unit 115 transmits at least one of video data and audio data to the electronic device 200, the power supply device 100 sends a response or information corresponding to the command via the power supply antenna 108. It can be received from the electronic device 200.

  Even when the communication unit 115 receives at least one of video data and audio data from the electronic device 200, the power supply device 100 sends a command or information to the electronic device 200 via the power supply antenna 108. Can be sent. Even when the communication unit 115 receives at least one of video data and audio data from the electronic device 200, the power supply device 100 sends a response or information corresponding to the command via the power supply antenna 108. It can be received from the electronic device 200.

  Next, an example of the configuration of the electronic device 200 will be described with reference to FIG.

  A digital still camera is taken as an example of the electronic device 200, and the following description will be given.

  The electronic device 200 includes a power receiving antenna 201, a matching circuit 202, a rectifying / smoothing circuit 203, a modem circuit 204, a CPU 205, a ROM 206, a RAM 207, a regulator 208, a charging control unit 209, a secondary battery 210, and a timer 211. Furthermore, the electronic device 200 includes a communication unit 212, an imaging unit 213, a recording unit 214, a recording medium 214a, an operation unit 215, and a display unit 216.

  The power receiving antenna 201 is an antenna for receiving power supplied from the power supply apparatus 100. The electronic device 200 receives power from the power supply device 100 or receives a command via the power receiving antenna 201. The electronic device 200 transmits a command for controlling the power supply device 100 and a response corresponding to the command received from the power supply device 100 via the power receiving antenna 201.

  The matching circuit 202 is a circuit for performing impedance matching with the power receiving antenna 201, the modem circuit, and the rectifying / smoothing circuit 203. Further, the power receiving antenna 201 is a circuit for resonating at the same frequency as the resonance frequency f of the power supply apparatus 100.

  Similar to the matching circuit 103, the matching circuit 202 includes a capacitor, a coil, a variable capacitor, a variable coil, a resistor, and the like. The matching circuit 202 controls the capacitance value of the variable capacitor, the inductance value of the variable coil, and the impedance value of the variable resistor so that the power receiving antenna 201 resonates at the same frequency as the resonance frequency f of the power supply apparatus 100.

  The matching circuit 202 supplies power received by the power receiving antenna 201 to the rectifying and smoothing circuit 203.

  The rectifying / smoothing circuit 203 generates DC power from the AC power received by the power receiving antenna 201. Further, the rectifying / smoothing circuit 203 supplies the generated DC power to the regulator 208. The rectifying / smoothing circuit 203 supplies a command extracted from the power received by the power receiving antenna 201 to the modem circuit 204. The rectifying / smoothing circuit 203 includes a rectifying diode and generates a DC voltage by full-wave rectification or half-wave rectification.

  The modulation / demodulation circuit 204 forms a diode detection circuit with a diode, a capacitor, and a resistor, detects an envelope of the change in the power supplied from the matching circuit 203 as a voltage change, and sends the envelope to the CPU 205. The CPU 205 receives the envelope detection signal from the matching circuit 203, analyzes the command from the power supply device 100 according to a predetermined communication protocol with the power supply device 100, and understands the command from the power supply device 100.

  The modem circuit 204 also sends a response to the command received from the power supply device 100 and predetermined information to the power supply device 100 through the power receiving antenna 201 by performing load modulation according to the control signal from the CPU 205.

  When the load included in the modem circuit 204 changes, the current flowing through the feeding antenna 108 changes. Accordingly, the power supply device 100 receives a command, a response to the command, and predetermined information transmitted from the electronic device 200 by detecting a change in the current flowing through the power supply antenna 108.

  The CPU 205 analyzes which command is the command received from the modem circuit 204 according to the modulation signal supplied from the modem circuit 204. Then, the electronic device 200 is controlled so as to perform processing and operation specified by the command code corresponding to the received command.

  In addition, the CPU 205 controls the operation of each unit of the electronic device 200 by executing a computer program recorded in the ROM 206.

  The ROM 206 records information such as a computer program for controlling the operation of each part of the electronic device 200 and parameters relating to the operation of each part. The ROM 206 records identification information of the electronic device 200, device information of the electronic device 200, display data, and the like used when the power supply device 100 and the electronic device 200 authenticate each other. The identification information of the electronic device 200 is information indicating an ID of the electronic device 200 or information indicating an address in communication of the electronic device 200, for example. The device information of the electronic device 200 includes the manufacturer name of the electronic device 200, the device name of the electronic device 200, the date of manufacture of the electronic device 200, and the like.

  A RAM 207 is a rewritable non-volatile memory, and records a computer program that temporarily controls the operation of each unit of the power supply apparatus 100, information such as parameters regarding the operation of each unit, information transmitted from the power supply apparatus 100, and the like.

  The regulator 208 controls the voltage of power supplied from the rectifying and smoothing circuit 203 and the voltage of power supplied from the secondary battery 210 so as to be fixed voltage values for operating the system. The regulator 208 may be a switching regulator or a linear regulator.

  The regulator 208 is not supplied with power from the secondary battery 210, but supplies power from the rectifying and smoothing circuit 203 to the entire electronic device 200 when power is supplied from the rectifying and smoothing circuit 203.

  The regulator 208 is not supplied with power from the rectifying and smoothing circuit 203, but when power is supplied from the secondary battery 210, the power supplied from the secondary battery 210 is transmitted to the entire electronic device 200 other than the charging control unit 209. Supply.

  When power is supplied from the rectifying / smoothing circuit 203 and the secondary battery 210, the regulator 208 supplies the electric power supplied from the rectifying / smoothing circuit 203 and the secondary battery 210 to the entire electronic device 200 other than the charging control unit 209. You can also

  When power is supplied from the rectifying / smoothing circuit 203 to the regulator 208, the charging control unit 209 charges the secondary battery 210 according to the supplied power. Note that the charging control unit 209 is an object for charging the secondary battery 210 by a constant voltage and constant current method as rapid charging. The charging control unit 209 performs charging with a smaller amount of power than rapid charging until the battery reaches a certain voltage from an empty state.

  The secondary battery 210 is a secondary battery that can be attached to and detached from the electronic device 200. The secondary battery 210 is a rechargeable battery, such as a lithium ion secondary battery. The secondary battery 210 can supply power to each part of the electronic device 200.

  The timer 211 measures the current time and the time related to operations and processes performed in each unit. A threshold for the time measured by the timer 211 is recorded in the ROM 206 in advance.

  The communication unit 212 can transmit video data and audio data recorded in the ROM 206 and the recording medium 214 a to the power supply device 100 and can receive video data and audio data from the power supply device 100.

  The communication unit 212 transmits and receives video data and audio data according to a communication protocol common to the communication unit 112. Further, for example, the communication unit 212 may transmit and receive video data and audio data in accordance with standards such as 802.11a, b, g, n, and ac defined as a wireless LAN.

  The imaging unit 213 is an imaging device for generating video data from the subject's optics, an image processing circuit that performs image processing on the video data generated by the imaging device, and compresses the compressed video data. It has a compression / decompression circuit for decompression. The imaging unit 213 captures a subject and supplies video data such as a still image or a moving image obtained from the result of the capture to the recording unit 214.

  The recording unit 214 records the video data supplied from the imaging unit 213 on the recording medium 214a. The imaging unit 213 may further have a necessary configuration for photographing a subject.

  The recording unit 214 records data such as video data and audio data supplied from any one of the communication unit 212 and the imaging unit 213 on the recording medium 214a.

  The recording unit 214 can also read data such as video data and audio data from the recording medium 214 a and supply the data to the RAM 207 and the communication unit 212.

  Note that the recording medium 214 a may be a hard disk, a memory card, or the like, and may be a built-in power supply device 100 or an external recording medium that is detachable from the power supply device 100.

  The operation unit 215 provides a user interface for operating the electronic device 200. The operation unit 215 includes a power button for operating the electronic device 200, a mode switching button for switching the operating mode of the electronic device 200, and the like. Each button includes a switch, a touch panel, and the like. The CPU 205 controls the electronic device 200 in accordance with a user instruction input via the operation unit 215. Note that the operation unit 215 may be an object that controls the electronic device 200 in accordance with a remote control signal received from a remote controller (not shown).

  The display unit 216 is a display device such as a liquid crystal or an organic EL, and displays a captured image recorded on the recording medium 214a or a live view image from the imaging unit 213.

  Note that the power feeding antenna 108 and the power receiving antenna 201 are objects that may be helical antennas, spiral antennas, or planar antennas such as meander line antennas.

  In the present embodiment, the processing performed by the power supply device 100 is an object that can be applied to a system in which the power supply device 100 supplies power to the electronic device 200 in a contactless manner by electromagnetic field coupling. Similarly, in the present embodiment, the processing performed by the electronic device 200 is an object that can be applied to a system in which the power supply device 100 supplies power to the electronic device 200 in a contactless manner by electromagnetic coupling.

  Further, the present invention is also applied to a system in which an electrode is provided in the power feeding device 100 as the power feeding antenna 108 and an electrode is provided in the electronic device 200 as the power receiving antenna 201 so that the power feeding device 100 supplies power to the electronic device 200 by electric field coupling. Can be applied.

  In addition, the present invention can also be applied to a system in which the power supply device 100 supplies power to the electronic device 200 in a non-contact manner by electromagnetic induction.

  In the present embodiment, the power supply device 100 transmits power to the electronic device 200 in a contactless manner, and the electronic device 200 is an object that receives power from the power supply device 100 in a contactless manner. However, “non-contact” is an object that may be rephrased as “wireless” or “non-contact”.

<Foreign matter detection processing control flow>
FIG. 3A is a diagram illustrating a control flow of foreign object detection processing of the power supply apparatus 100 according to the present embodiment. A foreign matter detection processing control flow of the power supply apparatus 100 will be described with reference to FIG. In the present embodiment, as a foreign object detection method of the power supply apparatus 100, the foreign object is determined based on the matching state of the matching circuit 104. However, the foreign object is detected using the voltage standing wave ratio VSWR (hereinafter referred to as SWR). Will be explained.

  In S301 of FIG. 3A, the CPU 105 of the power supply apparatus 100 sets a threshold value used for foreign object detection. For example, the threshold information used for foreign object detection is recorded in advance in the ROM 109, and the CPU 105 reads the information in the ROM 109 so that the threshold information used for foreign object detection is temporarily recorded in the RAM 110. The CPU 105 determines the presence or absence of foreign matter by comparing the threshold information with the SWR value information from the foreign matter detection circuit 116.

Here, a method of receiving the SWR value information by the CPU 105 and threshold information used for foreign object detection will be described. First, a method in which the CPU 105 receives SWR value information will be described.
The matching detection circuit 103 detects the aforementioned SWR value from the reflected wave and the traveling wave. The foreign object detection circuit 116 sends the SWR value detected by the foreign object detection circuit 110 at regular intervals to the CPU 105 as a foreign object determination signal. The CPU 105 reads the SWR value received from the foreign object detection circuit 116 and compares it with the threshold information recorded in the RAM 110 described above, thereby determining the presence or absence of the foreign object.

  Next, threshold information used for foreign object detection will be described. The threshold information used for foreign object detection is a value related to SWR fluctuation. In the present embodiment, the upper limit (first predetermined fluctuation value) of the fluctuation value per unit time of the SWR, the lower limit value of the fluctuation value (second predetermined fluctuation value), the amount of fluctuation of the SWR (predetermined fluctuation amount), and the SWR. Includes a duration (predetermined period) in which the variation has continued since the start of the variation.

  The CPU 105 compares these threshold values with the SWR value read from the foreign object detection circuit 116 and determines that it is a foreign object.

  In step S302, the CPU 105 performs main processing for detecting foreign matter. The detection main process will be described later.

  In S303, the CPU 105 determines whether or not to end the foreign object detection process. If it is determined that the process is not ended, the CPU 105 returns to S302 and repeats the detection process again.

  When the CPU 105 determines to end the foreign object detection process, the CPU 105 ends the foreign object detection process control. The CPU 105 determines whether or not to end the foreign object detection process when, for example, it is determined in S302 that there is a foreign object. If the CPU 105 determines that there is a foreign object in S302, it then controls the power transmission circuit 102 to weaken or stop the power supply output from the power supply antenna 108.

<About detection main processing>
Next, the detection main process in S302 will be described. FIG. 3B is a flowchart illustrating the operation of the power supply apparatus 100 during the detection main process.

  In S <b> 304, the CPU 105 reads the SWR (n) value of the foreign object detection circuit 116. Here, n is a natural number, and the SWR (n) value is the nth SWR. When the CPU 105 reads the SWR (n) value, the process proceeds to S305.

  In S305, the CPU 105 reads the SWR (n + 1) value that is the next SWR value in S304. When the CPU 105 reads the SWR (n + 1) value, the process proceeds to S306.

  In S306, the CPU 105 calculates a difference value between the SWR (n + 1) value and the SWR (n) value read in S304 and S305, and proceeds to S307.

  In S307, the CPU 105 determines whether or not the difference value calculated in S306 is equal to or less than a first predetermined value (for example, the SWR difference value is 4). If it is determined that the difference value calculated in S306 is greater than or equal to the first predetermined fluctuation value, it is determined that the SWR has fluctuated rapidly, so that it is not a fluctuation due to a foreign substance but a fluctuation of the SWR due to a load fluctuation of the power supply target electronic device 200. In this case, the process proceeds to S316, the timer value of the timer 107 is reset, the process of S302 ends, and the process proceeds to S303. Here, the timer value is the time after the difference value of SWR changes. In addition, the timer value does not need to be reset because it has not started counting at this time. However, in this embodiment, before the detection main process of S302 ends, the CPU 105 always resets the timer in S316 when the detection main process of S302 is ended to surely perform the process of returning to the initial value.

  If the difference value calculated in S306 is equal to or smaller than the first predetermined fluctuation value, the CPU 105 proceeds to S308 because there is a possibility that there is a foreign object.

  In S308, the CPU 105 determines whether or not the difference value calculated in S306 is equal to or less than a second predetermined value (for example, the SWR difference value is 0.5). If the difference value calculated in S306 is equal to or smaller than the second predetermined variation value, the CPU 105 determines that the variation in SWR is variation due to noise, proceeds to S316, resets the timer value, and ends the processing in S302. Proceed to S303. If the difference value calculated in S306 is greater than or equal to the second predetermined variation value, the CPU 105 proceeds to S309 because there is a possibility that foreign matter is present.

  In S309, the CPU 105 sets the timer value of the timer 107 and starts counting, and proceeds to S310.

  In S310, the CPU 105 records the SWR (n) value in the RAM 110, and proceeds to S311. Here, the reason for recording the SWR (n) value in the RAM 110 is to calculate the amount of change that is the difference from the latest SWR value used in S314.

  In S311, the CPU 105 detects the SWR (n + 2) value that is the next SWR value. When the CPU 105 detects the SWR (n + 2) value, the process proceeds to S312.

  In S312, the CPU 105 determines whether the sign of the difference between the SWR (n + 2) value and the SWR (n + 1) value (the sign of decrease or increase) is the same as the sign of the difference between the SWR (n + 1) value and the SWR (n) value. Therefore, it is determined whether or not the change is monotonous (increase or decrease). If it is determined that the change is monotonous, the CPU 105 proceeds to S313 because there is a possibility that there is a foreign object. If the CPU 105 determines that the change is not monotonous, it determines that the change is not the SWR change due to the foreign matter but the load change or noise caused by the electronic device 200, proceeds to S316, resets the timer value, and ends the process of S302. Proceed to S303. Here, the CPU 105 may count the number of times that does not change monotonously, and if the number of times changes more than a predetermined number (for example, 5 times), the CPU 105 may advance to S316 and end the processing of S302.

  In S313, the CPU 105 determines whether or not the timer value set in S309 has passed a predetermined period (for example, 200 ms). If the CPU 105 determines that the predetermined period has not elapsed, the process returns to S311 to detect the next SWR (n + 3) value and again determines whether or not the change is monotonous. If the CPU 105 determines that the predetermined period has elapsed, since it is a monotonous change, the CPU 105 determines that there is a possibility of foreign matter rather than noise and load fluctuations, and proceeds to S314.

  In S314, the CPU 105 reads the SWR (n) value recorded in the RAM 110 in S310, and further calculates the difference from the latest SWR value, so that the CPU 105 obtains the final fluctuation amount. Here, the latest SWR value is, for example, an SWR (n + 2) value when the process does not return to S311 in S313. When returning from S313 to S311 five times, the SWR (n + 7) value is the latest SWR value.

  If the fluctuation amount is equal to or less than a predetermined amount (for example, the fluctuation amount of the SWR value is 8), the CPU 105 determines that the final change is small, and thus the noise is determined. And the process proceeds to S303. If the amount of change is greater than or equal to the predetermined amount, the CPU 105 proceeds to S315.

  In S315, the CPU 105 determines that the amount of change in SWR is equal to or greater than the predetermined amount in S314. Therefore, the CPU 105 determines that there is a foreign object as a final determination result of the presence or absence of the foreign object, and proceeds to S316 to reset the timer value. The process of S302 ends and the process proceeds to S303.

  In this way, by performing the foreign substance detection processing control as shown in FIGS. 3A and 3B, not the amount of change in SWR (alignment state) but the manner of change (whether the change is steep). In order to determine the foreign object, it is possible to determine whether the load of the electronic device 200 is a foreign object or a foreign object. Therefore, the power supply apparatus 100 can reduce the erroneous detection of foreign matters.

  Note that the criterion for determining whether the load is a foreign object or a load variation of the electronic device 200 is that the SWR variation is steep because the electronic device 20 is electrically controlled in the case of a load variation. This is based on the fact that SWR changes more slowly than general control.

  Here, since the present invention determines the foreign matter based on the variation of the SWR, if the CPU 105 determines in S309 that the difference value of the SWR is not less than or equal to the second threshold value, the determination result in S309 is a foreign matter. May be determined. Similarly, in S313, if the change of the SWR is monotonous for a certain period, the CPU 105 may determine that the object is a foreign object based on the determination result in S313.

<About the SWR value fluctuation graph when determining whether there is a foreign object or not>
FIG. 4 is a graph showing the variation of time and SWR value in this embodiment, and FIG. 4 is a diagram showing the variation of SWR when it is determined that there is a foreign object and the variation of SWR when it is not determined that there is a foreign object. is there. That is, FIG. 4 shows what kind of SWR fluctuation is judged to have foreign matter and what kind of SWR fluctuation is judged to have no foreign matter when the foreign matter detection processing control explained in FIG. 3 is performed. FIG.

  The thin vertical lines in FIG. 4 indicate the sampling timing at which the foreign object detection circuit 116 in FIG. 2 performs SWR detection. Also, a thick solid line (1) in FIG. 4 is a graph showing a change in SWR when the CPU 105 determines that there is a foreign object in S315 in FIG. Thick dotted lines (2) to (4) are graphs showing fluctuations in SWR when the CPU 105 does not determine that there is a foreign object.

  A thick solid line (1) is determined by the CPU 105 as a foreign object because the SWR changes slowly and has a predetermined amount of change.

  A thick dotted line (2) is a graph that the CPU 105 has determined in step S312 that it is not a foreign object because it has not changed monotonously for a predetermined period.

  The thick dotted line (3) is a graph that the CPU 105 determines in S307 that the difference value of SWR is not less than or equal to the first predetermined value (a steep fluctuation) and is not a foreign object.

  The thick dotted line (4) is a graph that the CPU 105 has determined in step S314 that the fluctuation amount of the SWR is equal to or less than a predetermined amount, so that it is not a foreign object.

  As described above, in the case of the fluctuation graph of SWR shown in FIG. 4, the CPU 105 performs the foreign object detection process control of FIG.

[Second Embodiment]
In the second embodiment, a foreign object detection processing control flow when the power supply device 100 changes the foreign object detection threshold according to the power output will be described with reference to FIG. The reason why the threshold value is changed according to the power supply output is that when the power supply output is changed, the load of the electronic device 200 to be supplied varies, and it may be better to change the threshold value according to the power supply output. Since this embodiment has many parts in common with the first embodiment, the description will focus on parts specific to the second embodiment. The apparatus configuration is the same as in FIG. The detection main process is the same as that in FIG.

  In S501 of FIG. 5, the CPU 105 of the power supply apparatus 100 sets a threshold value used for foreign object detection.

  In step S502, the CPU 105 performs main processing for detecting foreign matter. When the detection main processing ends, the CPU 105 advances to step S503. Since the detection main process of S502 is the same as that of S302, detailed description thereof is omitted.

  In step S503, the CPU 105 determines whether the foreign object detection process is finished. If the CPU 105 determines that there is a foreign object in S502, it determines that the foreign object detection process has ended in S503, and ends this foreign object detection process control. If the CPU 105 determines that the foreign object detection process is not completed, the process proceeds to S504.

  In step S504, the CPU 105 determines whether the power supply output has changed during the detection main process in step S502. Whether or not the power supply output has changed is determined by the foreign object detection circuit 116 detecting the output power of the power transmission circuit 102 in FIG. 2 or the output power from the power supply antenna 108, and the CPU 105 receiving information from the foreign object detection circuit 116. To determine whether or not the power supply output has changed.

  If the CPU 105 determines that the power supply output has changed, the process proceeds to S505. If it is determined that the power supply output has not changed, the process returns to S502, and the detection main process is performed again.

  In S505, the CPU 105 resets each predetermined threshold set in S501 to a threshold corresponding to the power supply output, and returns to S502 again. Here, the threshold corresponding to the power supply output is recorded in advance in the ROM 109 as a table of each power supply output and threshold information. In step S505, the CPU 105 reads the ROM 109 and resets the threshold value. Alternatively, a coefficient may be recorded in advance in the ROM 109, and a threshold value set from the power supply output on the spot and the coefficient recorded in advance may be calculated according to the power supply power detected by the CPU 105.

  As described above, since the power supply device 100 of the present invention changes the threshold value used when detecting foreign matter according to the power supply output, even if the power supply output changes and the load on the electronic device 200 changes, the threshold value is set to an optimum value. Since the change is made, it is possible to detect a foreign object with fewer false detections.

<Other embodiments>
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

Claims (11)

A power feeding device that feeds power in a contactless manner through an antenna to a power receiving device,
A generation unit that generates feed power output from the antenna, a matching unit that is connected between the antenna and the generation unit, a detection unit that detects a change in the matching state of the matching unit, and a foreign object is within a predetermined range Determination means for determining whether or not,
The determination means determines the presence / absence of a foreign object using a fluctuation value per unit time of the alignment state detected by the detection means, or a duration in which fluctuation continues after the fluctuation value and fluctuation occur and / or a duration A power supply device that determines the presence or absence of a foreign object using a fluctuation amount between the two.   The power supply device according to claim 1, wherein the determination unit determines that there is a foreign object when the variation value per unit time is smaller than a first predetermined variation value.   The power supply device according to claim 1, wherein the determination unit determines that there is a foreign object when the amount of change is smaller than a first predetermined variation value and the duration is longer than the predetermined period.   The determination means determines that there is a foreign object when the change amount is smaller than a first predetermined fluctuation value, the duration is longer than a predetermined period, and the fluctuation amount is larger than the predetermined fluctuation amount. The power feeding device according to claim 1 or 2.   5. The determination unit according to claim 2, wherein the determination unit does not determine that there is a foreign object when the variation value is smaller than a second predetermined variation value that is smaller than the first predetermined variation value. 6. The power supply equipment described.   The determination means further does not determine that there is a foreign object when the positive and negative changes in the sign of the fluctuation value are equal to or greater than a predetermined number of times during the duration. Or a power supply device according to item 1.   The said determination means has 1 or more threshold value which determines the presence or absence of a foreign material, and each threshold value changes a threshold value according to the output which the said production | generation means produces | generates. The power supply equipment described.   When the variation value determined by the determination unit is greater than a first predetermined variation value and / or the variation amount is greater than the predetermined variation amount, the detection unit returns the duration to zero, 8. The power supply apparatus according to claim 7, wherein the matching state is detected again.   The power supply device according to claim 1, wherein the detection unit repeats detection at regular intervals. A control method for a power supply device that includes a generation unit that generates power to be supplied from an antenna, and a matching unit that is connected between the antenna and the generation unit, and that supplies power to the power receiving device in a contactless manner through the antenna Because
A detection step for detecting a change in the alignment state of the alignment means, and a determination step for determining whether or not the foreign matter is within a predetermined range,
In the determination step, the presence / absence of a foreign object is determined using the variation value per unit time of the alignment state detected by the detection step, or the duration in which the variation continues after the variation value and the variation occur and / or the duration A method for controlling a power feeding device, wherein the presence or absence of a foreign object is determined using a fluctuation amount between the two.   A computer-readable program for causing a computer to function as the power supply device according to any one of claims 1 to 9.

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