JP5431774B2 - Wireless power transmission apparatus and wireless power transmission method - Google Patents

Description

  The present invention relates to wireless power transmission.

  In the field of land transportation, research and development of automobiles that run on electric power has been actively conducted due to concerns about air pollution and depletion of fossil fuels. As an automobile that travels using electric power, for example, there is a type that travels using electric power stored in a secondary battery. As a technique for charging a secondary battery mounted on an automobile, there is a technique for charging by receiving power from a power feeding unit provided on a traveling path in a non-contact manner (see, for example, Patent Document 1). In addition, as a technique for wirelessly transmitting power, there is a technique that sends power with high transmission efficiency to devices separated by magnetic resonance (see, for example, Patent Document 2).

JP 2008-120357 A JP 2008-301918 A

  Conventionally, there is a wireless power transmission technique by electromagnetic induction between coils. However, the electromagnetic induction power transmission method has the advantage that there is no need to expose the contacts on the power transmission side and the power reception side, but the transmission efficiency drops extremely as the coil interval becomes longer. In most cases, it was used in such a state.

  In addition to such an electromagnetic induction method, conventionally, there is a wireless power transmission technology that uses magnetic resonance (Magnetic Resonance, both magnetic resonance, magnetic resonance, and magnetic resonance) between coils having the same resonance frequency. In the power transmission method using magnetic field resonance, the coil interval can be made longer than in the electromagnetic induction method. However, in the power transmission method using magnetic field resonance, the coil interval can be set more flexibly than electromagnetic induction, so there is a risk that objects (including animals) may enter the electric field / magnetic field. There is a possibility of affecting power transmission efficiency and safety.

  In view of the above-described problems, an object of the present invention is to make it possible to appropriately cope with an intrusion of an object between power transmission units in wireless power transmission.

  The present invention is a wireless power transmission apparatus for performing wireless power transmission between a power transmission unit and a power reception unit, and an intrusion of an object into a space that affects wireless power transmission is related to wireless power transmission. A parameter acquisition unit that acquires a plurality of predetermined parameters; and an intrusion determination unit that determines that the intrusion has occurred when the acquired predetermined parameter has changed by a predetermined threshold or more as time elapses; Is a wireless power transmission device.

  That is, according to the present invention, one or more parameters are always created (for example, at regular intervals) during normal power transmission / reception, and it is detected that one or more parameters have changed. If it is determined that an intrusion has occurred. Instead of directly detecting the occurrence of intrusion based on a change in parameters, a method of comparing previously prepared profile information with parameters or the like may be used.

  For example, the present invention relates to a wireless power transmission device for performing wireless power transmission between a power transmission unit and a power receiving unit, and an intrusion of an object into a space that affects wireless power transmission relates to the wireless power transmission. Information holding means for holding in advance profile information indicating the content of influence on one or a plurality of predetermined parameters, parameter acquisition means for acquiring the one or more predetermined parameters, and the acquired predetermined parameters, or The content of the change of the predetermined parameter over time is compared with the profile information, and according to the comparison result between the predetermined parameter or the content of the change and the profile information (for example, the predetermined parameter or the change of the change). An intrusion that determines that the intrusion has occurred (if the content approximates or matches the profile information) A constant section, a wireless power transmission device comprising a.

  The present invention detects intrusion into a space (electric field / magnetic field) used for power transmission in wireless power transmission. INDUSTRIAL APPLICABILITY The present invention can be applied to wireless power transmission in which foreign matter or the like may enter a space used for power transmission and power reception. Conventionally, as such wireless power transmission, power transmission using electromagnetic induction, power transmission using magnetic resonance, and power transmission using radio waves such as microwaves are known. In addition, intruders to be detected in the present invention include animals (including humans) in addition to foreign objects such as metals that are considered to have a large effect on power transmission.

  In the present invention, in such a wireless power transmission apparatus, one or a plurality of predetermined power transmission related to wireless power transmission is utilized by utilizing that the intrusion into the space used for power transmission affects the parameters related to wireless power transmission. A parameter is acquired, and it is determined that an intrusion has occurred when the acquired parameter or the content of the parameter change obtained by this parameter acquisition approximates or matches the profile information prepared in advance. The predetermined parameter acquired here is a measured value acquired by various sensors provided in the apparatus or a control value used for controlling various elements included in the apparatus. Specific contents of the acquired predetermined parameter will be described later.

  The contents of parameter changes include the amount of change of parameters per time, the balance between a plurality of parameters, the tendency of parameter changes, and the like. In the present invention, such a parameter and the change contents of the parameter are compared with profile information prepared in advance, and it is determined whether the profile is within a predetermined threshold range based on the profile information. An approximation or a match to information is determined.

  According to the present invention, by performing intrusion detection based on a comparison between an acquired parameter or parameter change content and profile information, it is possible to perform appropriate measures against detected intrusion such as power transmission stop or warning. .

  Further, in the present invention, the information holding unit holds in advance the profile information indicating the content of the influence on the predetermined parameter for each type of intrusion or intrusion mode, and the intrusion determination unit When it is determined that the predetermined parameter or the content of the change approximates or matches the profile information, it may be determined that an intrusion of an object type or aspect corresponding to the profile information has occurred.

  Here, the type of the object is a classification according to the magnitude and type of the influence on the power transmission of the object related to the intrusion, and examples thereof include metals, animals, and humans. The intrusion mode is an element other than the intruder among the elements related to the intrusion. Examples of the intrusion include an intrusion direction and an intrusion position in a space to be intruded. In the present invention, profile information is prepared for each type of object and the mode of intrusion, and the type of object related to the intrusion and the mode of intrusion can be determined, so that it is more appropriate when an intrusion is detected. It is possible to take corrective actions.

  The wireless power transmission device according to the present invention is a wireless power transmission that transmits power by generating magnetic field resonance between a power transmission coil provided in the power transmission unit and a power reception coil provided in the power reception unit. In the apparatus, the one or more predetermined parameters are: power transmission efficiency measured in the power transmission coil, resonance state between the power transmission coil and the power reception coil, and transmission efficiency indicating a ratio of power reception power to power transmission power, Any of these may be included.

  Here, the power transmission efficiency measured in the power transmission coil is, for example, the power transmission efficiency calculated based on the reflected wave detected in the power transmission coil (for example, the standing wave ratio calculated based on the traveling wave and the reflected wave is used). Or the power transmission capability of the power transmission unit indicating the ratio of the power actually transmitted from the power transmission amplifier to the power transmission coil with respect to the input power from the external power source. Further, by acquiring a change in the phase of the current received by the power receiving coil and comparing the acquired change in the phase with predetermined profile information, it is possible to detect intrusion based on a change in the resonance state.

  The present invention also relates to a wireless power transmission apparatus for wirelessly transmitting power between a power transmission unit and a power receiving unit, and determines an intrusion determination that determines the occurrence of an object intrusion into a space that affects wireless power transmission. And when the intrusion determination means determines that the intrusion has occurred, the transmission stop means for stopping the power transmission, and when the intrusion determination means no longer determines that the intrusion has occurred, A wireless power transmission apparatus comprising: a transmission restarting unit that restarts the power transmission.

By providing such transmission stop means and transmission resumption means, when it is no longer determined that an intrusion has occurred, wireless power transmission that has been once stopped can be resumed.

  The transmission restarting unit may restart the power transmission after a predetermined time elapses when the intrusion determination unit no longer determines that the intrusion has occurred. By doing in this way, it can prevent that stop and restart of electric power transmission are repeated within a short time by repeating invasion. In addition, since it is confirmed that there is no intrusion again, power transmission is resumed, so that safer power transmission can be performed.

  In addition, the wireless power transmission device according to the present invention provides a notification that notifies the resumption of power transmission before resuming the power transmission by the transmission resuming means when the intrusion judging means no longer determines that the intrusion has occurred. An output means may be further provided. By doing so, it is possible to alert the user and the intruder and perform safer power transmission.

  The present invention also relates to a wireless power transmission apparatus for wirelessly transmitting power between a power transmission unit and a power receiving unit, and determines an intrusion determination that determines the occurrence of an object intrusion into a space that affects wireless power transmission. And a warning output means for outputting a warning when the intrusion determination means determines that the intrusion has occurred. By doing in this way, when the invading object is an animal or a person, it is possible to prompt the user to leave the space used for power transmission or to prompt the user to remove the intruding object.

Furthermore, the present invention can be understood as a method executed by the wireless power transmission apparatus or a program executed by a computer that controls the wireless power transmission apparatus. By causing the wireless power transmission apparatus to execute the control method for the wireless power transmission apparatus according to the present invention or the control program for the wireless power transmission apparatus according to the present invention, the same functions and effects as described above can be exhibited. Is possible. Such a program can be provided by being recorded on a recording medium readable by a computer, other devices, machines, or the like, or can be provided by downloading to a computer using a communication line. Here, a computer-readable recording medium is a recording medium that stores information such as data and programs by electrical, magnetic, optical, mechanical, or chemical action and can be read from a computer or the like. Say.

  For example, the present invention relates to a wireless power transmission apparatus for performing wireless power transmission between a power transmission unit and a power receiving unit, wherein an intrusion of an object into a space that affects wireless power transmission is related to wireless power transmission or Information holding step for preliminarily holding profile information indicating contents of influence on a plurality of predetermined parameters, parameter acquisition step for acquiring the one or more predetermined parameters, and the acquired predetermined parameters or time A determination step of comparing the content of the change of the predetermined parameter with the profile information and determining that the intrusion has occurred according to a comparison result between the predetermined parameter or the content of the change and the profile information; Is a wireless power transmission method.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to perform an appropriate countermeasure with respect to the penetration | invasion of the thing between power transmission units in wireless power transmission.

It is a figure which shows the structure of the wireless power transmission system which concerns on embodiment. It is a figure which shows the structure of the power transmission coil and power receiving coil which are used in embodiment. It is a figure which shows the outline | summary of the 3 coil structure in embodiment. It is a flowchart which shows the flow of the intrusion detection process performed in the wireless power transmission system which concerns on embodiment. Figure comparing the state of eddy currents when only the metal plate is placed on the back side of the unit and the state of suppressing eddy currents when the magnetic shield sheet is placed on the metal plate on the back side of the unit It is. It is a figure which shows a mode that the magnetic shield sheet | seat was provided in the back surface of the power transmission coil installed in the ground, and the back surface of the receiving coil installed in a vehicle.

  Embodiments of a wireless power transmission apparatus and a wireless power transmission method according to the present invention will be described below with reference to the drawings. The wireless power transmission system 1 according to the present embodiment is a system for transmitting electric power charged in an in-vehicle battery to the vehicle side. The power transmission unit is on the ground side where the vehicle stops, and the power receiving unit is the vehicle. Provided on the side. However, the power transmission system according to the present invention is not limited to vehicle use, and can be applied to various devices using electric power, such as home appliances, information devices, and toys.

<Configuration of wireless power transmission system>
FIG. 1 is a diagram illustrating a configuration of a wireless power transmission system 1 according to the present embodiment. The wireless power transmission system 1 is roughly provided with two wireless power transmission devices, a power transmission unit 10 and a power reception unit 20. Among these, the power transmission unit 10 is provided on the ground side of a position where the vehicle stops (for example, a parking space), and includes a power transmission controller 17, a converter 13, a power transmission amplifier 14, a power transmission coil 15, a resonance control unit 16, an oscillation circuit 18, An intrusion sensor 11, a directional coupler 19, a traveling wave power meter 19a, a reflected wave power meter 19b, a load matching device 19c, and a data transmission / reception unit 12 are provided. Here, the power transmission coil 15 is opposed to the power reception coil 25 provided on the bottom surface of the vehicle at a position where the alignment is easy when the vehicle stops, such as a predetermined position based on the parking stop of the parking space. It is preferable to be provided.

The power transmission controller 17 is a computer that is connected to a storage device and operates the power transmission unit 10 as a power transmission unit 10 including an information holding unit, a parameter acquisition unit, and an intrusion determination unit by executing a control program. The power transmission controller 17 sets the oscillation circuit 18, the resonance control unit according to the preset power transmission settings, the data transmission / reception unit 12 data transmission / reception result with the power reception unit 20, and the transmission power monitor result obtained from the power transmission amplifier 14. 16. Control the converter 13. The data transmission / reception unit 12 is a communication interface for wireless communication connected to an antenna. Further, the converter 13 converts the supplied AC or DC power into a DC current and sends it to the power transmission amplifier 14. The output voltage from the converter 13 is controlled by the power transmission controller 17. Further, the power transmission amplifier 14 inputs the power transmitted from the converter 13 to the power transmission coil 15 at the frequency given from the oscillation circuit 18. Here, the frequency given by the oscillation circuit 18 is controlled by the power transmission controller 17.

  The resonance control unit 16 matches the resonance frequency of the power transmission unit 10 with the oscillation frequency of the oscillation circuit 18 by a method such as controlling the capacitance of the capacitor (capacitor) provided in the power transmission coil 15 in accordance with an instruction from the power transmission controller 17. Control to do. Further, the oscillation circuit 18 controls the frequency oscillated to the power transmission coil 15 to a predetermined value in accordance with an instruction from the power transmission controller 17.

  The directional coupler 19 takes out the traveling wave and the reflected wave of the power input from the power transmission amplifier 14 to the power transmission coil 15. The traveling wave power meter 19a and the reflected wave power meter 19b measure the power of the traveling wave and the power of the reflected wave extracted by the directional coupler 19, and the measured results are transmitted power monitor values and reflected power. The monitor value is notified to the power transmission controller 17. The load matching unit 19c performs matching between the power transmission amplifier 14 and the load.

  The power receiving unit 20 is provided in a vehicle and includes a power receiving controller 27, a power receiving coil 25, a resonance control unit 26, a rectifier circuit 28, a DC / DC converter 29, an intrusion sensor 21, and a data transmission / reception unit 22. Similar to the resonance control unit 16, the resonance control unit 26 controls the resonance frequency of the power reception unit 20 to coincide with the oscillation frequency of the oscillation circuit 18 in accordance with an instruction from the power reception controller 27. As a result, the resonance frequency of the power transmission unit 10 and the resonance frequency of the power reception unit 20 are controlled to coincide with each other, and wireless power transmission by magnetic field resonance is possible. Here, the power receiving coil 25 is preferably provided at a position on the bottom surface of the vehicle facing the power transmission unit 10 installed on the ground. The power receiving unit 20 is connected to the in-vehicle battery 33 via the in-vehicle charge / discharge control device 31. The charge / discharge control device 31 discharges electric power for driving the vehicle from the in-vehicle battery 33 in response to the accelerator operation, and when the brake is operated, the electric power generated by the motor 32 is supplied to the in-vehicle battery 33. Controlled to be charged.

  The power receiving controller 27 is connected to the storage device, and operates the power receiving unit 20 as a power receiving unit 20 including information holding means, parameter acquisition means, and intrusion determination means by executing a control program connected to the storage device. Computer. The power receiving controller 27 is configured according to the resonance control unit 26, the rectifying circuit, and the power receiving unit 27 according to the preset power receiving settings, the data transmission / reception result of the data transmission / reception unit 22 with the power transmission unit 10, and the received power monitoring result obtained from the rectifying circuit 28. 28 and DC / DC converter 29 are controlled. The data transmission / reception unit 22 is a communication interface for wireless communication connected to an antenna. Further, a current flows through the power receiving coil 25 due to magnetic field resonance with the power transmitting coil 15. Here, the power reception controller 27 controls the resonance control unit 26 so that the resonance frequency of the power reception coil 25 matches that of the power transmission unit 10 in order to generate magnetic field resonance with the power transmission coil 15.

The rectifier circuit 28 (AC / DC converter) and the DC / DC converter 29 can control the apparent load resistance on the power reception side by changing the voltage on the power transmission side by keeping the electric power taken out on the charge / discharge control side constant. .

  The intrusion sensors 11 and 21 are a method for analyzing an image captured by a camera, an acoustic wave or a radio wave, for the approach of an object to the periphery of the vehicle, the lower space of the vehicle, the lower space of the power receiving coil 25, It is a sensor for detecting using means such as a system using reflection, a system using light blocking, and an infrared detection system. In the present embodiment, a method of performing intrusion detection by comparing parameters or parameter change contents related to wireless power transmission and profile information will be mainly described. In addition to this method, intrusion detection by intrusion sensors 11 and 21 is described. May be used supplementarily or separately. For example, the controllers 17 and 27 use the intrusion sensors 11 and 21 to detect objects in the vicinity of the vehicle, the lower space of the vehicle, the lower space of the power receiving coil 25, and the upper space of the power transmitting coil 15, and at the same time, When a distance from a predetermined reference (for example, the power transmission coil 15 or the power reception coil 25) for intrusion detection is acquired and the distance to the object is equal to or less than a predetermined threshold, or the distance to the object is predetermined. It may be determined that an intrusion has occurred when a state that is less than or equal to the threshold value continues for a predetermined time or longer. In the present embodiment, an intrusion detection method other than intrusion detection based on comparison of parameters and the like related to wireless power transmission and profile information is also described. When not used for detection, the intrusion sensors 11 and 21 may be omitted.

  FIG. 2 is a diagram illustrating the configuration of the power transmission coil 15 and the power reception coil 25 used in the present embodiment. The coil shown in FIG. 2 is a coil having a four-coil configuration in which the first power transmission coil 15a and the second power transmission coil 15b are used as the power transmission coil 15, and the first power reception coil 25a and the second power reception coil 25b are used as the power reception coil 25. is there. Here, the first power transmission coil 15a is a two-turn coil having a diameter of 170 mm, the second power transmission coil 15b and the first power reception coil 25a are coils having a diameter of 250 mm and a tenth turn, and the second power reception coil 25b. Is a one-turn coil with a diameter of 157 mm.

  Here, the first power transmission coil 15 a is a coil to which power is directly supplied from the power transmission amplifier 14. When a current flows through the first power transmission coil 15a by the power transmission amplifier 14, electromagnetic induction occurs between the first power transmission coil 15a and the second power transmission coil 15b, and a current flows through the second power transmission coil 15b. Then, when a current flows through the second power transmission coil 15b by electromagnetic induction, magnetic field resonance occurs between the second power transmission coil 15b and the first power reception coil 25a whose resonance frequencies are matched, and a current flows through the first power reception coil 25a. Flows. Further, when a current flows through the first power receiving coil 25a due to magnetic field resonance, electromagnetic induction occurs between the first power receiving coil 25a and the second power receiving coil 25b, and a current flows through the second power receiving coil 25b. In the example illustrated in FIG. 2, a coil through which a current is directly supplied from the power transmission amplifier 14 and a coil directly connected to the load resistance on the power reception side (here, the first power transmission coil 15 a and the second power reception coil 25 b), and magnetic resonance The coils used for power transmission by the power transmission (here, the second power transmission coil 15b and the first power reception coil 25a) are not physically connected, but are connected by electromagnetic induction, thereby configuring the power transmission amplifier 14, the load resistance, and the like. However, the influence on the resonance frequency of the coil used for the magnetic field resonance is suppressed.

  In FIG. 2, as a representative example, a four-coil configuration of two coils on the power transmission side and two coils on the power reception side is illustrated, but the present invention is wireless based on magnetic field resonance between the power transmission coil 15 and the power reception coil 25. The present invention is applicable to a system using power transmission, and the number of coils is not limited to the above four-coil configuration. For example, a two-coil configuration including one power transmission side coil and one power receiving side coil may be employed, or a three coil configuration including one power transmission side coil and two power receiving side coils may be employed. The two coils on the power receiving side in the three-coil configuration are the first power receiving coil 25a and the second power receiving coil 25b that are connected by electromagnetic induction. FIG. 3 is a diagram showing an outline of a three-coil configuration in the present embodiment.

<Intrusion detection processing>
FIG. 4 is a flowchart showing a flow of intrusion detection processing performed in the wireless power transmission system 1 according to the present embodiment. In the processing shown in this flowchart, the power receiving coil 25 provided on the vehicle side and the power transmitting coil 15 provided in a parking lot or the like are aligned, and the processing for adjusting the resonance frequency is completed to prepare for power transmission. It is started when this is completed. Note that the specific contents and order of the processes shown in this flowchart are examples, and it is preferable that processes suitable for the embodiment are appropriately adopted as the process contents and order.

  In step S101, power transmission / reception is started. The power transmission controller 17 controls the oscillation circuit 18 according to the preset contents or the result of communication with the power receiving side via the data transmission / reception units 12 and 22, and causes a current to flow through the coil at the determined frequency and voltage. Since this frequency is the resonance frequency of the power transmission unit 10 and the power reception unit 20, magnetic field resonance occurs between the power transmission coil 15 and the power reception coil 25 by this power transmission, and the power reception unit 20 can receive power. Thereafter, the process proceeds to step S102.

  In step S102, various parameters related to wireless power transmission are acquired. The power transmission controller 17 and the power reception controller 27 obtain parameters related to wireless power transmission from various sensors provided in the wireless power transmission system 1. Here, the various sensors and controllers 17 and 27 provided in the wireless power transmission system 1 correspond to a parameter acquisition unit according to the present invention. Specifically, the power transmission controller 17 acquires input power from the converter 13, acquires transmission power from the power transmission amplifier 14, acquires traveling wave power from the traveling wave power meter 19 a, and reflects a reflected wave power meter 19 b. The power of the reflected wave is obtained from In addition, the power reception controller 27 acquires the power reception frequency and the power reception power from the rectifier circuit 28. Here, the parameters acquired by the power receiving controller 27 are sent to the power transmission controller 17 via the data transmission / reception units 12 and 22, and the parameters acquired by the power transmission controller 17 are transmitted via the data transmission / reception units 12 and 22. It is sent to the power receiving controller 27. In this embodiment, the power transmission controller 17 and the power reception controller 27 transmit and receive parameters via the data transmission / reception units 12 and 22, so that the space between the power transmission coil 15 and the power reception coil 25 in both the controllers 17 and 27. It is possible to perform intrusion detection for.

  Further, the power transmission controller 17 and the power reception controller 27 are based on the acquired primary parameters, (1) power transmission efficiency in the power transmission coil 15, (2) power transmission capacity of the power transmission unit 10 as a whole for input power, and (3) Secondary parameters such as the power transmission efficiency between the power transmission coil 15 and the power reception coil 25 are obtained by calculating based on the primary parameters obtained from the sensors.

(1) Power transmission efficiency in power transmission coil 15 More specifically, the controllers 17 and 27 detect the traveling wave power and the reflected wave detected by the traveling wave power meter 19a and the reflected wave power meter 19b in the power transmission coil 15. Based on the power, the power transmission efficiency in the power transmission coil 15 is calculated. The calculated power transmission efficiency may be any information that can grasp the ratio (power transmission efficiency) of the power input to the power transmission coil 15 that is actually transmitted to the power receiving side. The standing wave ratio based on the power of the traveling wave and the power of the reflected wave may be calculated.

(2) The power transmission capacity of the power transmission unit 10 as a whole with respect to the input power The controllers 17 and 27 calculate the ratio of the power actually transmitted from the power transmission amplifier 14 to the power transmission coil 15 with respect to the input power from the external power source. The power transmission capacity of the power transmission unit with respect to the input power is calculated.

(3) Power transmission efficiency between the power transmission coil 15 and the power reception coil 25 The controllers 17 and 27 calculate the ratio of the power reception monitored by the rectifier circuit 28 to the power transmission power monitored by the power transmission amplifier 14. Thus, the transmission efficiency is calculated. The power transmission controller 17 can acquire the received power from the power receiving unit 20 side via the data transmission / reception units 12 and 22, and the power reception controller 27 can receive the power transmission unit 10 side via the data transmission / reception units 12 and 22. Transmission power can be acquired from

  The parameters thus calculated are also transmitted and received between the power transmission controller 17 and the power reception controller 27 via the data transmission / reception units 12 and 22. Note that the acquired parameters are held in the storage device for at least a certain period of time in order to continuously monitor the contents of parameter changes. In the present embodiment, at least the parameters exemplified above are acquired as parameters used for intrusion detection. However, the acquired parameters are preferably selected as appropriate according to the embodiment. When all the parameters used for intrusion detection are acquired, the process proceeds to step S103.

  In step S103, the content of the parameter change is acquired. The power transmission controller 17 and the power reception controller 27 are configured to detect the difference between the various parameters acquired in step S102 and the various parameters previously acquired, the amount of change of parameters per time, the balance between a plurality of parameters, and the change of parameters. By calculating the trend or the like, the content of the parameter change is acquired. For example, the controllers 17 and 27 acquire the content of the change in the resonance state of the magnetic field resonance by acquiring the phase change (deviation) of the current received by the power receiving coil 25 over time. Similarly, the controllers 17 and 27 acquire, as parameter change contents, changes in power transmission efficiency, power transmission unit power transmission capacity, transmission efficiency, and the like over time. Thereafter, the process proceeds to step S104.

  In step S104 and step S105, the acquired parameter and the change content of the parameter are compared with the profile information, and intrusion detection is performed. The controllers 17 and 27 compare the parameter and the parameter change content acquired in steps S102 and S103 with the profile information read from the storage device. Here, the controllers 17 and 27 correspond to intrusion determination means according to the present invention.

  In the present embodiment, the profile information includes one or a plurality of intrusions of objects with respect to a space that affects wireless power transmission, such as a space between the power transmission coil 15 and the power receiving coil 25 in the wireless power transmission system 1. It is the information which shows the content of the influence which it has on the parameter. The profile information is stored in a state in which parameters or parameter changes measured by conducting experiments or simulations in advance for each intruder and intrusion mode are associated with the intruder or intrusion mode as a map or relational expression. Held in the device. That is, the storage device and the controllers 17 and 27 correspond to information holding means according to the present invention. For this reason, the controllers 17 and 27 specify the parameters obtained in step S102 and step S103 and the profile information that approximates or matches the change contents of the parameters, so that the intruder or the intrusion mode is detected in addition to the intrusion detection. Also identify. The controllers 17 and 27 determine whether the acquired parameter or the like (parameter or parameter change content) is within a predetermined range based on the profile information, thereby obtaining the acquired parameter or the like. It can be determined whether or not the profile information approximates or matches.

If it is determined that an intrusion has occurred because the parameter or the like approximates or matches the profile information, the process proceeds to step S106. If it is determined that no intrusion has occurred, the process proceeds to step S102. That is, in the process shown in this flowchart, the presence or absence of intrusion during power transmission / reception is monitored by repeatedly executing the process shown in steps S102 to S105 after the start of power transmission / reception.

  In step S106, safety control is executed. The controllers 17 and 27 perform control necessary for ensuring safety for each element of the wireless power transmission system 1. Specifically, stoppage of power transmission, suppression of transmission power, output of warning / alarm, instruction on how to recover from malfunction, etc. are performed. For example, when power transmission is stopped, the controllers 17 and 27 give an instruction to the converter 13 or the power transmission amplifier 14 to cut off the power supply from the external power source or input power to the power transmission coil 15. To stop the power transmission. Here, the controllers 17 and 27 correspond to transmission stop means according to the present invention.

  In this embodiment, since the intruder or the intrusion mode can be specified, safety control is performed according to the specified intruder or intrusion mode. For example, if the detected intruder is metal, etc., and it is detected that the voltage or current on the power receiving side exceeds a specified value that is not problematic for safe operation, the circuit on the power receiving side, etc. In order to protect, it is preferable that power transmission is stopped or transmitted power is suppressed. When the transmission power is suppressed, the controllers 17 and 27 give an instruction to the power transmission amplifier 14 to reduce the power input to the power transmission coil 15 and set the power reception side received power to a specified value. And protect the circuit on the power receiving side. The transmission power may be suppressed by switching the charging mode from the quick charging to the normal charging when an intrusion is detected during the quick charging.

  In addition, the warning / alarm output and the instruction for the recovery method from the malfunction may be performed independently, but may be performed in conjunction with the above-described stoppage of power transmission or suppression of transmission power. The controllers 17 and 27 provide a warning / alarm output instruction signal or a return method output instruction signal to the warning output devices 34 and 44 such as a display and a speaker connected to the wireless power transmission system 1, thereby providing a car navigation system. Alarm / alarm display and recovery method display on the display of the car and dashboard, and warning / alarm sound output and speaker output of the speaker of the car audio system. Here, the controllers 17 and 27 and the warning output devices 34 and 44 correspond to warning output means according to the present invention. In addition, the warning / alarm may be output to an animal or a person who has entered the lower part of the vehicle. Warnings / alarms are output in a manner that can be perceived by animals and humans, such as voice and images.

  In addition, when the power transmission is stopped, the controllers 17 and 27 restart the power transmission when a predetermined condition is satisfied. For example, the controllers 17 and 27 start counting the time after the intrusion is no longer detected, and compare the elapsed time with a predetermined threshold, thereby transmitting power after a predetermined time has elapsed since the intrusion is no longer detected. Can be resumed. However, depending on the embodiment, power transmission may be resumed immediately after intrusion is no longer detected. Here, the controllers 17 and 27 correspond to transmission restarting means according to the present invention. Further, when the power transmission is resumed, the controllers 17 and 27 may output an instruction for notifying the user and the intruder of the power transmission resume to the warning output devices 34 and 44. Here, the controllers 17 and 27 and the warning output devices 34 and 44 correspond to notification output means according to the present invention. By notifying the restart of power transmission before power transmission is resumed, it is possible to suppress power transmission stoppage due to re-entry.

In the wireless power transmission system 1 according to the present embodiment, in addition to the intrusion detection based on the profile comparison described above, a failure state is detected, power transmission is stopped, transmission power is suppressed, warning / alarm output, It is planned to take measures such as instructions on how to recover. For example, a power reception device (resonance frequency) provided other than the positional deviation between the power transmission coil 15 and the power reception coil 25, a malfunction of the power reception circuit, the entry of a foreign object or an animal, or an assumed target (a vehicle in this embodiment). It is preferable that power reception due to the same), power transmission device failure, communication interruption between the data transmission / reception units 12 and 22, etc. be detected as faulty states.

  Such a failure state is detected by, for example, acquiring transmission efficiency, power transmission efficiency, power transmission unit power transmission capacity, power receiving side information, input power, and the like and evaluating the acquired value by comparing with a threshold value. I can do it. Here, since calculation methods, such as transmission efficiency, power transmission efficiency, and power transmission unit power transmission capability, are as described above, description thereof will be omitted. As for the transmission efficiency, when the calculated current transmission efficiency is equal to or lower than a predetermined transmission efficiency (threshold) that is set in advance, the calculated current transmission efficiency is set to a predetermined value that is set in advance. When the power transmission efficiency (threshold value) is less than or equal to the power transmission unit power transmission capacity, the current state of the calculated power transmission unit power transmission capacity is equal to or lower than a predetermined power transmission unit power transmission capacity (threshold value) set in advance. It can be determined that For example, according to the power transmission unit power transmission capability, a failure of the power transmission device can be detected.

  The power receiving side information can be acquired when the power transmission controller 17 detects the interruption of communication via the data transmitting / receiving units 12 and 22 from the power receiving unit 20 side. Further, regarding the input power, when the current input power acquired from the converter 13 is equal to or higher than a predetermined input power (threshold value) set in advance, it can be determined that the state is in a trouble state. In addition, the failure state is detected by sweeping the transmission frequency around a predetermined frequency and comparing the state of change of traveling wave power and reflected wave power at that time with the state of change (profile information) assumed in advance. May be.

  In addition, the malfunction state may be detected by intrusion sensors 11 and 21 that detect the entry of an object into an area such as the lower part of the vehicle by means such as a light shielding type or an infrared detection type. Furthermore, it is good also as not performing wireless power transmission during boarding by performing a boarding detection using a seat sensor, a door sensor, etc.

  According to the wireless power transmission system 1 according to the present embodiment, intrusion of a foreign object into a space used for power transmission in wireless power transmission or a malfunction state that may occur in wireless power transmission is detected, and wireless power transmission is performed. Safety can be improved. In particular, according to the intrusion detection method that compares the parameters related to wireless power transmission and the profile information, intrusion detection can be performed without providing a separate intrusion detection sensor.

  By the way, when the power transmission side unit and the power reception side unit for performing wireless power transmission are attached to the power reception side device and the power transmission side equipment, a magnetic body such as an iron plate may exist on the back side of the unit. For example, when a power receiving unit is installed in an automobile, a magnetic body (iron plate) such as a chassis or body of the automobile inevitably exists on the back surface of the power receiving unit. In this case, magnetism due to power transmission reaches the magnetic body, and eddy current is generated in the magnetic body. As a result, energy loss due to the eddy current is caused and power transmission efficiency is lowered.

  Therefore, in the present embodiment, a magnetic shield sheet is disposed in the vicinity of the coils on the power transmission side and the power reception side that perform wireless power transmission, specifically on the back surface. As this magnetic shield sheet, a synthetic rubber sheet containing a flat soft magnetic powder (for example, a flexible noise suppression sheet “DPR” manufactured by Daido Steel Co., Ltd.) or the like can be used. FIG. 5 shows how eddy currents are generated when only the metal plate is arranged on the back side of the unit, and how eddy currents are suppressed when the magnetic shield sheet is arranged on the metal plate on the back side of the unit. FIG.

Specifically, for example, as shown in FIG. 6, the coils for power transmission and reception are arranged facing each other, the power transmission side is a magnetic shield sheet on the back of the power transmission coil, and the vehicle side which is the power reception side is the power reception coil, magnetic shield sheet, vehicle It is preferable to arrange in the order of (BODY). The size of the magnetic shield sheet is preferably sufficiently larger than the diameter of the coil so that the coil can be covered. In addition, the direction, arrangement, distance, and the like of the coil and the magnetic shield sheet are preferably set as appropriate while confirming through experiments, for example, in consideration of power transmission efficiency. Of course, in consideration of efficiency, it is preferable that the sheet bend (coil covering method), shape, thickness, size, and the like are appropriately designed through experiments and the like.

  In addition, according to such an embodiment, since the magnetism behind the magnetic shield sheet is shielded, it is also possible to obtain an effect that there is almost no influence of power transmission energy on the vehicle-side passengers and electronic devices receiving power. is there.

DESCRIPTION OF SYMBOLS 1 Wireless power transmission system 10 Power transmission unit 15 Power transmission coil 17 Power transmission controller 20 Power reception unit 25 Power reception coil 27 Power reception controller

Claims (16)

A wireless power transmission device for performing wireless power transmission between a power transmission unit and a power reception unit,
Parameter acquisition for acquiring power transmission efficiency in a power transmission coil based on traveling wave power and reflected wave power as predetermined parameters relating to the wireless power transmission in order to determine intrusion of an object into a space that affects wireless power transmission Means,
Intrusion determination means for determining that the intrusion has occurred when the acquired predetermined parameter has changed over time;
A wireless power transmission device comprising: A wireless power transmission device for performing wireless power transmission between a power transmission unit and a power reception unit,
Information holding means for holding in advance profile information indicating the content of the influence of an entry of an object on a space affecting wireless power transmission on a predetermined parameter relating to wireless power transmission;
Parameter acquisition means for acquiring the power transmission efficiency of the power transmission coil based on the traveling wave power and the reflected wave power as the predetermined parameter;
The acquired predetermined parameter or the content of the change of the predetermined parameter over time is compared with the profile information, and according to the comparison result between the predetermined parameter or the content of the change and the profile information, the Intrusion determination means for determining that an intrusion has occurred;
A wireless power transmission device comprising: The information holding means holds in advance the profile information indicating the content of the effect on the predetermined parameter for each type of intrusion or intrusion mode,
The intrusion determination means determines that an object type or an intrusion mode corresponding to the profile information has occurred when it is determined that the predetermined parameter or the content of the change approximates or matches the profile information.
The wireless power transmission device according to claim 2. A wireless power transmission device that transmits power by generating magnetic field resonance between a power transmission coil provided in the power transmission unit and a power reception coil provided in the power reception unit,
The one or more predetermined parameters include any one of power transmission efficiency measured in the power transmission coil, a resonance state between the power transmission coil and the power reception coil, and a transmission efficiency indicating a ratio of power reception power to power transmission power. ,
The wireless power transmission device according to any one of claims 1 to 3. If the penetration is determined to have occurred by the previous SL intrusion determination means, a transmission stop means for performing stop of the power transmission,
A transmission resumption means for resuming the power transmission when the intrusion determination means no longer determines that the intrusion has occurred;
The wireless power transmission device according to any one of claims 1 to 4, further comprising: The transmission resumption means waits for the elapse of a predetermined time when the intrusion determination means no longer determines that the intrusion has occurred, and resumes the power transmission.
The wireless power transmission device according to claim 5. When it is determined that the intrusion has not occurred by the intrusion determination unit, the intrusion determination unit further includes a notification output unit that notifies the resumption of power transmission before the resumption of power transmission by the transmission resumption unit.
The wireless power transmission apparatus according to claim 5 or 6. When the intrusion by the previous SL intrusion determining means is determined to have occurred, and a warning output means for performing the warning output,
The wireless power transmission device according to any one of claims 1 to 7, further comprising: A wireless power transmission device for performing wireless power transmission between a power transmission unit and a power reception unit,
Parameter acquisition for acquiring power transmission efficiency in a power transmission coil based on traveling wave power and reflected wave power as predetermined parameters relating to the wireless power transmission in order to determine intrusion of an object into a space that affects wireless power transmission Steps,
A determination step of determining that the intrusion has occurred when the acquired predetermined parameter has changed over time; and
A wireless power transmission method for executing. A wireless power transmission device for performing wireless power transmission between a power transmission unit and a power reception unit,
An information holding step for holding in advance profile information indicating the content of the influence of an entry of an object on a space affecting wireless power transmission on a predetermined parameter related to wireless power transmission;
As the predetermined parameter, a parameter acquisition step of acquiring power transmission efficiency in the power transmission coil based on traveling wave power and reflected wave power;
The acquired predetermined parameter or the content of the change of the predetermined parameter over time is compared with the profile information, and according to the comparison result between the predetermined parameter or the content of the change and the profile information, the A determination step for determining that an intrusion has occurred;
A wireless power transmission method for executing. In the information holding step, the profile information indicating the content of the influence on the predetermined parameter is held in advance for each type of intrusion or intrusion mode,
In the determination step, when it is determined that the predetermined parameter or the content of the change approximates or matches the profile information, it is determined that an object type corresponding to the profile information or an intrusion mode has occurred.
The wireless power transmission method according to claim 10. The wireless power transmission device transmits electric power by generating magnetic field resonance between a power transmission coil provided in the power transmission unit and a power reception coil provided in the power reception unit,
The one or more predetermined parameters include any one of power transmission efficiency measured in the power transmission coil, a resonance state between the power transmission coil and the power reception coil, and a transmission efficiency indicating a ratio of power reception power to power transmission power. ,
The wireless power transmission method according to any one of claims 9 to 11. A transmission stop step for stopping the power transmission when it is determined in the determination step that the intrusion has occurred;
A transmission resumption step for resuming the power transmission when it is no longer determined that the intrusion has occurred in the determination step;
The wireless power transmission method according to claim 9, wherein the wireless power transmission method is executed. In the transmission restart step, when it is no longer determined that the intrusion has occurred in the determination step, the power transmission is restarted after a lapse of a predetermined time.
The wireless power transmission method according to claim 13. When it is no longer determined that the intrusion has occurred in the determination step, a notification output step of notifying the restart of power transmission is further performed before the restart of power transmission in the transmission restart step.
The wireless power transmission method according to claim 13 or claim 14. A warning output step for outputting a warning when it is determined in the determination step that the intrusion has occurred;
The wireless power transmission method according to claim 9, wherein the wireless power transmission method is executed.

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