JP2012005226A - Wireless power transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wireless power transmission system capable of attaining high safety.SOLUTION: When it is detected that a medical instrument wearer approaches a vehicle 10, transmission power from a primary coil 35 of a charger 30 to a secondary coil 15 of the vehicle 10 is suppressed. When electric power is wirelessly transmitted, electromagnetic waves may leak between the primary coil 35 and the secondary coil 15 to the outside. The intensity of an electromagnetic wave propagates more highly and widely as the power supplied to the primary coil 35 is higher. For example, when a medical instrument wearer receives electromagnetic waves, it may have an adverse effect upon a medical instrument. According to the present invention, when the medical instrument wearer is present around the vehicle, the transmission power from the primary coil 35 to the secondary coil 15 is suppressed, thereby suppressing the adverse effect of electromagnetic waves upon the medical instrument.

Description

  The present invention relates to a wireless power transmission system for charging a vehicle.

  In recent years, electric cars and hybrid cars that can be driven by electric power have attracted attention. These vehicles include an in-vehicle battery, and electric power is supplied to the in-vehicle battery from a power supply source provided outside the vehicle. Thereby, the vehicle-mounted battery is charged.

  Conventionally, in the charging of an in-vehicle battery, a wired power transmission system that performs power transmission from a power supply source to a vehicle via a charging cable has been adopted. However, in recent years, the adoption of a wireless power transmission system that wirelessly transmits power from a power supply source to a vehicle has been studied from the viewpoint of improving convenience.

  Specifically, a coil is provided for each of the vehicle and the power supply source. When starting charging, the vehicle is stopped so that the coil faces the coil of the power supply source. When AC power is supplied to the coil on the power supply source side, the coil generates magnetic flux. When this magnetic flux enters the vehicle side coil, an electromotive force is generated in the coil. Thus, it is called electromagnetic coupling that both coils are electrically coupled via magnetic flux. This electromagnetic coupling enables wireless power transmission from the power supply source to the vehicle. This eliminates the trouble of attaching and detaching the charging cable to and from the vehicle during charging, and improves convenience (for example, see Patent Document 1).

JP-A-8-237890

  By the way, in the above configuration, not all the magnetic flux generated by the coil on the power supply source side enters the coil on the vehicle side, but actually leakage magnetic flux is always generated. This leakage magnetic flux increases due to, for example, positional deviation between both coils. As the leakage magnetic flux increases, the range covered by electromagnetic waves generated based on the magnetic flux increases. In this case, a user existing around the vehicle may receive electromagnetic waves. Here, when a user wears a medical device such as a pacemaker, there is a concern that the medical device may be affected. Such problems of electromagnetic waves during power transmission can occur not only in electromagnetic induction type wireless power transmission through electromagnetic coupling but also in other magnetic field resonance types and radio wave reception types.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a wireless power transmission system with improved safety.

In the following, means for achieving the above object and its operational effects will be described.
According to a first aspect of the present invention, in a wireless power transmission system for charging a battery of the vehicle by wirelessly transmitting power from a power transmission unit of an external power source to a power reception unit of the vehicle, it detects that a person has approached the vehicle. The gist of the invention is that it includes a human detection unit and a control device that suppresses transmission power from the power transmission unit to the power reception unit when it is detected that a person approaches the vehicle through the human detection unit. .

  According to this configuration, when it is detected that a person has approached the vehicle through the person detection unit, the transmitted power from the power transmission unit to the power reception unit is suppressed. Here, when power is transmitted wirelessly between the power transmission unit and the power reception unit, the emission of electromagnetic waves becomes a problem. This electromagnetic wave is stronger as the transmitted power becomes larger and propagates over a wide area. For example, when a person wearing a medical device such as a pacemaker receives electromagnetic waves, there is a concern that the medical device may be affected. In this regard, according to the present configuration, when a person is present around the vehicle, radiation of electromagnetic waves is suppressed by reducing the transmission power, so that the influence on the medical device can be suppressed. Thereby, the safety | security of a wireless power transmission system can be improved.

  According to a second aspect of the present invention, in the wireless power transmission system according to the first aspect, the wireless signal is carried by the user and transmits a radio signal including information on whether or not the user is a medical device wearer. When the wireless signal is received from the portable device, the human detection unit detects that a user has approached the vehicle, and the control device detects the human detection based on the received wireless signal. The gist is to suppress the transmission power from the power transmission unit to the power reception unit only when the user approaching the vehicle detected through the means recognizes that the user is a medical device wearer.

  According to this configuration, the transmission power is suppressed only when the user of the portable device is recognized as a medical device wearer. Therefore, when there is a portable device user who is not a medical device wearer around the vehicle, the transmitted power is not suppressed, and the transmitted power and thus the charged power to the battery can be maintained. Thereby, the safety | security with respect to a medical device wearer can be improved, ensuring the transmitted power from a vehicle external power supply to a vehicle.

  According to a third aspect of the present invention, in the wireless power transmission system according to the second aspect, the radio signal includes an ID code, and the control device recognizes the validity of the ID code included in the radio signal. The gist is that the vehicle door can be unlocked.

  According to this configuration, the wireless signal includes an ID code related to unlocking the vehicle door. Therefore, the portable device does not need to transmit a radio signal only to suppress the transmission power.

  According to the present invention, safety can be improved in a wireless power transmission system.

1 is a configuration diagram of a wireless power transmission system. FIG. The flowchart which showed the process sequence of the power supply control program.

Hereinafter, an embodiment embodying a wireless power transmission system according to the present invention will be described with reference to FIGS.
As shown in FIG. 1, a vehicle 10 that is an electric vehicle is charged by a charging device 30 provided in a parking lot. The charging device 30 is transmitted from the vehicle 10, a charging side control unit 31 that performs the control, a primary coil 35 embedded in the parking lot ground, a power supply circuit 32 that supplies power to the primary coil 35, and the vehicle 10. A receiving circuit 37 and a receiving antenna 37a for receiving a command signal to be transmitted, and a charging switch 33 operated by a user when charging is started and stopped.

  When the charging switch 33 is operated, the operation signal is output to the charging side control unit 31. When recognizing that the charging switch 33 has been operated, the charging side control unit 31 supplies an alternating current to the primary coil 35 via the power supply circuit 32. When the charging side control unit 31 recognizes that the charging switch 33 has been operated again, it stops the power supply to the primary coil 35.

The vehicle 10 includes a vehicle side control unit 11, a charging circuit 12, a battery unit 13, a motor 14, and a secondary coil 15.
The secondary coil 15 is provided at a position facing the primary coil 35 in the parked vehicle 10. The primary coil 35 generates magnetic flux when AC power is supplied from the power supply circuit 32. Since AC power is supplied from the power supply circuit 32, the magnetic flux of the primary coil 35 changes with time. An electromotive force is generated when the time-varying magnetic flux of the primary coil 35 enters the secondary coil 15. As a result, wireless power transmission from the primary coil 35 to the secondary coil 15 becomes possible. Here, as described in the background art above, in the power transmission through the electromagnetic coupling between the coils 15 and 35, an electromagnetic wave is generated based on the leakage magnetic flux. As shown in FIG. 2, when viewed from above the vehicle 10, the electromagnetic wave propagates to a first propagation area 55 formed in a range extending to the side of the vehicle 10 with both the coils 15 and 35 as the center.

  As shown in FIG. 1, the charging circuit 12 converts the electromotive force (AC power) of the secondary coil 15 into DC power and supplies the DC power to the battery unit 13. Thereby, the battery unit 13 can be charged. The vehicle-side control unit 11 performs control related to charging of the battery unit 13 through the charging circuit 12. The charging circuit 12 includes a voltage sensor that detects the voltage of the battery unit 13. The vehicle-side control unit 11 can recognize whether or not the charging of the battery unit 13 has been completed based on the detection result of the voltage sensor.

  The battery unit 13 includes a switch circuit and the like in addition to the battery. The vehicle-side control unit 11 allows or blocks power supply from the battery unit 13 to the motor 14 through the switch circuit. The motor 14 is driven based on the electric power from the battery unit 13. When power supply from the battery unit 13 to the motor 14 is permitted, the driving wheels of the vehicle are driven through the motor 14 and can travel.

  Moreover, the vehicle side control part 11 is provided with the non-volatile memory 11a, and the ID code set individually for the vehicle 10 is stored in the memory 11a. The vehicle 10 is equipped with an electronic key system that can lock and unlock the vehicle door through communication with the electronic key 20 carried by the user.

  The vehicle 10 includes a transmission circuit 18, a transmission antenna 18a, a reception antenna 17a, and a reception circuit 17. The transmission circuit 18 modulates the request signal input from the vehicle side control unit 11 into a radio wave having a predetermined frequency. In the present embodiment, the predetermined frequency is an LF (Low Frequency) band frequency. The transmission antenna 18a transmits the request signal modulated by the transmission circuit 18 around the vehicle.

  As shown in FIG. 2, the transmission circuit 18 and the transmission antenna 18a are built in the door handle of each vehicle door. Therefore, the request signal is transmitted to the communication area 50 formed in a semicircular shape around the door handle as viewed from above the vehicle 10. Each communication area 50 is formed so as to cover each other and include the first propagation area 55 outside the vehicle. Each door handle is provided with a door handle switch 19. As shown in FIG. 1, when the door handle switch 19 is operated, an operation signal to that effect is output to the vehicle-side controller 11.

  The electronic key 20 includes a key-side control unit 21, a transmission circuit 28, a transmission antenna 28a, a reception antenna 27a, and a reception circuit 27. The receiving antenna 27a receives a request signal transmitted from the vehicle 10. The receiving circuit 27 demodulates the request signal received by the receiving antenna 27 a and outputs the demodulated signal to the key control unit 21.

  The key-side control unit 21 includes a non-volatile memory 21a. In this memory 21a, the ID code that is the same as the ID code stored in the memory 11a of the vehicle 10 and the user who carries the electronic key 20 are pacemakers or the like. An information code indicating whether or not the user wears a medical device (hereinafter referred to as a medical device wearer) is stored. When the request signal is input from the receiving circuit 27, the key-side control unit 21 generates a response signal including the ID code and the information code stored in the memory 21a and outputs the response signal to the transmission circuit 28. The transmission circuit 28 modulates the response signal input from the key-side control unit 21 into a radio wave having a predetermined frequency. In the present embodiment, the predetermined frequency is an RF (Radio Frequency) band frequency. The transmission antenna 28a transmits the response signal modulated by the transmission circuit 28. At this time, the user carrying the electronic key 20 is located outside the first propagation area 55 and within the communication area 50.

  The receiving antenna 17 a of the vehicle 10 receives the response signal from the electronic key 20. The receiving circuit 17 demodulates the response signal received through the receiving antenna 17 a and outputs the demodulated signal to the vehicle-side control unit 11.

  The vehicle-side control unit 11 determines whether the carrier of the electronic key 20 is a medical device wearer based on the information code included in the response signal. When determining that the vehicle-side control unit 11 is a medical device wearer, the vehicle-side control unit 11 generates a command signal for suppressing the power supplied to the primary coil 35, and transmits the command signal to the transmission circuit 18 and the transmission antenna 18a. Send through. This command signal is a radio wave in the LF band like the request signal. The receiving antenna 37 a of the charging device 30 receives a command signal from the vehicle 10. Specifically, as shown in FIG. 2, the charging device 30 receives a command signal from a transmission circuit 18 or the like provided on the door handle of the back door of the vehicle 10. That is, the charging device 30 needs to be installed in the communication area 50 when the vehicle 10 is parked. The receiving circuit 37 demodulates the command signal received through the receiving antenna 37 a and outputs the demodulated signal to the charging side control unit 31. The charging side control unit 31 suppresses the power supplied to the primary coil 35 via the power supply circuit 32 based on the command signal. Accordingly, the magnetic flux generated by the primary coil 35 and, consequently, the leakage magnetic flux between the coils 15 and 35 are reduced. Thereby, the propagation range of the electromagnetic waves due to the leakage magnetic flux is suppressed. As a result, as shown in FIG. 2, the area where the electromagnetic wave propagates changes from the first propagation area 55 to the second propagation area 56 smaller than that. The second propagation area 56 is accommodated in the vehicle as viewed from above the vehicle 10. Therefore, when the electromagnetic wave is propagating to the second propagation area 56, even if the medical device wearer exists around the vehicle, the person is suppressed from receiving the electromagnetic wave. In other words, the power supplied to the primary coil 35 is set small enough that the second propagation area 56 does not reach the outside of the vehicle. Thereby, the influence by the electromagnetic waves on the medical device of the medical device wearer can be suppressed.

  The vehicle control unit 11 collates the ID code included in the response signal with the ID code stored in the memory 11a. The vehicle side control part 11 will be in an unlocking permission state, when collation of ID code is materialized. When receiving an operation signal indicating that the door handle switch 19 has been operated in the unlocking permitted state, the vehicle-side control unit 11 unlocks the vehicle door via the door lock device 16.

  Here, regardless of whether or not the ID code is verified, a command signal is transmitted if the response signal includes an information code indicating that the user of the electronic key 20 is a medical device wearer. That is, the electronic key 20 may not correspond to the vehicle 10. That is, the medical device wearer is prevented from receiving electromagnetic waves from not only the own vehicle but also other vehicles only by carrying the electronic key 20.

  Next, a supply power control program executed by the vehicle side control unit 11 will be described. The program is executed according to the flowchart shown in FIG. In addition to this program, a door lock control program for unlocking the vehicle door through exchange of request signals and response signals, ID code verification, and the like is executed independently.

  When the power supply control program is started, the vehicle 10 is parked so that both the coils 15 and 35 face each other and the back door of the vehicle 10 faces the charging device 30. A request signal is transmitted around the vehicle 10 at predetermined intervals.

  The supply power control program is started when charging of the battery unit 13 is started through the charging circuit 12. First, it is determined whether or not a response signal has been received (S101). If it is determined that no response signal has been received (NO in S101), it is determined whether charging of the battery unit 13 has been completed (S102). When the charging of the battery unit 13 is completed (YES in S102), the program is terminated. When charging of the battery unit 13 is not completed (NO in S102), it is determined again whether or not a response signal has been received (S101). That is, during charging, whether or not a response signal is received is constantly monitored.

  When it is determined that the response signal has been received (YES in S101), that is, when the approach of the user to the vehicle 10 is detected, the user carrying the electronic key 20 is based on the information code included in the response signal. It is determined whether the user is a medical device wearer (S103). If it is determined that the user is not a medical device wearer (NO in S103), the program ends. As a result, when a person who is not a medical device wearer carries the electronic key 20 and enters the communication area 50, the power supplied to the primary coil 35 and the charging power to the battery unit 13 are suppressed. There is no. Therefore, the battery unit 13 can be charged quickly.

  When it is determined that the user is a medical device wearer (YES in S103), a command signal is transmitted (S104). As a result, the power supplied to the primary coil 35, and thus the propagation range of the electromagnetic wave, is suppressed, and the influence of the electromagnetic wave on the medical device can be suppressed.

As described above, according to the embodiment described above, the following effects can be obtained.
(1) When it is detected that the medical device wearer has approached the vehicle 10, the transmission power from the primary coil 35 of the charging device 30 to the secondary coil 15 of the vehicle 10 is suppressed. Here, when electric power is transmitted wirelessly, electromagnetic waves may leak between the primary coil 35 and the secondary coil 15. This electromagnetic wave is stronger as the power supplied to the primary coil 35 becomes larger and propagates over a wide range. For example, when a medical device wearer receives electromagnetic waves, there is a concern that the medical device may be affected. In this regard, according to the present embodiment, when a medical device wearer is present around the vehicle, the transmission power from the primary coil 35 to the secondary coil 15 is suppressed, so that the influence of electromagnetic waves on the medical device is suppressed. can do. Thereby, the safety | security of a wireless power transmission system can be improved.

  (2) The transmission power from the primary coil 35 to the secondary coil 15 is suppressed only when it is determined that the user is a medical device wearer based on the response signal from the electronic key 20. Therefore, when the electronic key 20 of a person who is not a medical device wearer is present around the vehicle, the transmission power is not suppressed by the response signal from the electronic key 20, and the power supplied to the primary coil 35, and thus the battery The charging power to the unit 13 can be maintained. Thereby, the safety | security with respect to a medical device wearer can be improved, maintaining the transmitted power from the charging device 30 to the vehicle 10. FIG.

  (3) The request signal is transmitted to the communication area 50. When each communication area 50 is viewed as a single communication area formed around the vehicle, the single area includes the first propagation area 55, that is, protrudes around the first propagation area 55. It is formed. Therefore, the response signal is transmitted when the medical device wearer carrying the electronic key 20 is present around the vehicle (exactly within the communication area 50 and outside the first propagation area 55) that does not receive electromagnetic waves. Is done. Thereby, the vehicle-side control unit 11 can suppress the propagation range of the electromagnetic wave before the medical device wearer enters the first propagation area 55. Further, the electronic key 20 automatically returns a response signal in response to the request signal. For this reason, the user can suppress the propagation range of electromagnetic waves without operating the electronic key 20.

In addition, the said embodiment can be implemented with the following forms which changed this suitably.
In the above embodiment, when a medical device wearer carrying the electronic key 20 enters the communication area 50, the power supplied to the primary coil 35 is suppressed. However, the power supplied to the primary coil 35 may be suppressed without distinguishing whether or not the user is a medical device wearer. In this case, the information code included in the response signal is omitted. That is, when the vehicle 10 recognizes the response signal from the electronic key 20, the command signal is transmitted to the charging device 30 regardless of the success or failure of the ID verification, thereby suppressing the propagation range of the electromagnetic wave.

  In the above embodiment, when a medical device wearer carrying the electronic key 20 enters the communication area 50, the power supplied to the primary coil 35 is suppressed. However, the power supply to the primary coil 35 may be stopped through the command signal so that electromagnetic waves are not generated.

  -In above-mentioned embodiment, when the charge switch 33 was operated, charge of the battery unit 13 was started. However, the charging of the battery unit 13 may be started when the user leaves the vehicle 10 after the charging switch 33 is operated. Specifically, when the response signal from the electronic key 20 is not returned to the request signal, the vehicle 10 determines that the user has left the vehicle 10 and sends a request signal for requesting the start of charging to the charging device 30. Send. The charging device 30 starts supplying power to the primary coil 35 based on the received request signal. Thereby, charging of the battery unit 13 is started. According to this control, the medical device wearer carrying the electronic key 20 is prevented from receiving electromagnetic waves immediately after the start of charging, and the safety can be further improved.

  In the above-described embodiment, the charging device 30 suppresses the power supplied to the primary coil 35 and thus the propagation range of electromagnetic waves based on the command signal from the vehicle 10. However, when the charging device 30 directly receives the response signal via the receiving circuit 37 or the like and recognizes the information code indicating that the user is a medical device wearer included in the response signal, the charging device 30 supplies the response signal to the primary coil 35. The supplied power may be suppressed. In this case, the vehicle 10 does not need to transmit a command signal and can more quickly suppress the propagation range of the electromagnetic wave.

  In the above-described embodiment, the electronic key system mounted on the vehicle 10 is an operation free key that allows the vehicle door to be unlocked without operating the electronic key 20 through bidirectional communication between the vehicle 10 and the electronic key 20. It was a system. However, you may employ | adopt the wireless key system which enables locking / unlocking of a vehicle door by the one-way communication from the electronic key 20 to the vehicle 10. FIG. In this case, the electronic key 20 includes a lock switch and an unlock switch. When the lock switch is operated, a lock request signal including an ID code and an information code is transmitted from the electronic key 20 to the vehicle 10, and when the unlock switch is operated, the ID code and the information code are transmitted from the electronic key 20 to the vehicle 10. An unlock request signal including is transmitted. The vehicle 10 receives the locking request signal, and locks the vehicle door when collation of the ID code included in the signal is established. In addition, the vehicle 10 receives the unlock request signal, and unlocks the vehicle door when collation of the ID code included in the signal is established. When the vehicle 10 recognizes the information code indicating that it is a medical device wearer included in the locking or unlocking request signal, the vehicle 10 suppresses the propagation range of the electromagnetic wave through the command signal. Thereby, similarly to the said embodiment, the influence of the electromagnetic waves to the medical device of a medical device wearer is suppressed. Furthermore, a dedicated switch for suppressing electromagnetic waves may be provided on the electronic key 20. In this case, when the switch is operated, the electronic key 20 transmits a request signal for requesting the vehicle 10 to suppress electromagnetic waves. Based on the request signal, the vehicle 10 transmits a command signal to suppress power supplied to the primary coil 35. Also in this case, the charging device 30 may receive a request signal from the electronic key 20 without passing through the vehicle 10 and suppress the power supplied to the primary coil 35 based on the request signal.

  -The electronic key function which concerns on locking and unlocking of a vehicle door from the electronic key 20 in the said embodiment is abbreviate | omitted, and it is good also as a dedicated portable machine which suppresses the influence of the electromagnetic waves to a medical device wearer. Further, for example, a function of suppressing the influence of electromagnetic waves on the medical device wearer may be added to the mobile phone. In these configurations, an ID code used in the electronic key function can be omitted.

  In the above embodiment, when the user who has entered the communication area 50 is a medical device wearer, the propagation range of the electromagnetic wave is suppressed through the command signal. Further, thereafter, it may be periodically monitored whether or not there is a medical device wearer in the communication area 50. For example, after transmitting a command signal in step S104, the presence / absence of reception of a response signal is monitored as in step S101. When no response signal is received, the medical device wearer returns from the communication area 50 to the original power supplied to the primary coil 35. Thereby, the charging power to the battery unit 13 when the medical device wearer does not exist in the communication area 50 can be secured.

  In the above embodiment, the information code indicating whether or not the user is a medical device wearer is stored in the memory 21 a of the electronic key 20. However, information on whether or not the user is a medical device wearer may be registered in the memory 11a of the vehicle 10. Here, the ID code included in the response signal is different for each electronic key such as a main key and a sub key. For example, it is assumed that information indicating that the user of the main key is a medical device wearer and the sub key user is not a medical device wearer is registered in the memory 11a of the vehicle 10. In this case, the vehicle 10 suppresses the propagation range of the electromagnetic wave through the command signal when receiving the response signal from the main key, and does not transmit the command signal when receiving the response signal from the sub key.

  In the above embodiment, the electronic key 20 transmits a response signal including an information code to the request signal transmitted from the vehicle 10. However, the electronic key 20 may transmit an RF band warning signal including an information code every predetermined period separately from the response signal. When the vehicle 10 receives the warning signal, the vehicle 10 suppresses the propagation range of the electromagnetic wave. Here, the RF band signal transmitted from the electronic key 20 reaches farther than the LF band signal transmitted from the vehicle. Therefore, the propagation range of the electromagnetic wave can be suppressed before entering the communication area 50 by the warning signal transmitted from the electronic key 20 at a position away from the vehicle 10. Thereby, the influence of electromagnetic waves on the medical device of the medical device wearer can be more reliably suppressed.

  In the above embodiment, when the vehicle 10 receives a response signal to the request signal, it can detect that a person has approached. However, as long as it is a human detection unit that detects the approach of a person to the vehicle 10, a human sensor or a camera using ultrasonic waves and infrared rays may be used. Further, the approach of a person may be detected through footsteps. In these configurations, similarly to the above, the propagation range of the electromagnetic wave is suppressed through the reduction of the power supplied to the primary coil 35 without distinguishing whether or not the person approaching the vehicle 10 is a medical device wearer. .

  In the above embodiment, when a medical device wearer carrying the electronic key 20 enters the communication area 50, the propagation range of electromagnetic waves is suppressed. In addition to this, a warning that there is a risk of receiving electromagnetic waves through the electronic key 20 may be given. Specifically, during charging, the vehicle 10 transmits the request signal including information indicating that charging is in progress. When the electronic key 20 recognizes that the received request signal includes information indicating that charging is in progress, the electronic key 20 warns the user through warning means. As warning means, for example, a speaker that emits sound, a vibration generating device that generates vibration, or a display device such as a display can be employed. Moreover, you may perform only the said warning, without suppressing the propagation range of electromagnetic waves.

  In the above embodiment, charging is performed by electromagnetic induction type wireless power transmission using the electromagnetic coupling of both coils 15 and 35, but the type is not limited as long as it is wireless power transmission. Charging may be performed by wireless power transmission of a type and a radio wave reception type.

In the above embodiment, the vehicle 10 is an electric vehicle, but may be a hybrid car that can run on both gasoline and electricity.
Next, the technical idea that can be grasped from the embodiment will be described together with the effects.

  (A) In the wireless power transmission system according to any one of claims 1 to 3, the control device transmits a command signal to request suppression of transmitted power to the external power source, and the external power source A wireless power transmission system that suppresses transmitted power based on the received command signal.

According to this configuration, the transmitted power from the power transmission unit of the external power source is suppressed based on the command signal.
(B) In the wireless power transmission system according to claim 3, the control device transmits a request signal to an area including a range in which an electromagnetic wave generated based on transmitted power from the power transmission unit to the power reception unit propagates. The portable device receives the request signal outside the range in which the electromagnetic wave propagates, and transmits the wireless signal in response to the request signal.

  According to this configuration, when the portable device carried by the user receives a request signal, a wireless signal is returned, whereby the vehicle door can be unlocked and transmission power is suppressed. Since these are automatically performed without the user operating the portable device, convenience can be improved. The request signal is transmitted to an area including a range in which an electromagnetic wave generated based on the transmission power propagates. Therefore, before the portable device carried by the user enters the range in which the electromagnetic wave propagates, a response signal is transmitted through reception of the request signal, and transmitted power is suppressed. Thereby, the range which electromagnetic waves propagate becomes small and it is suppressed that a user receives electromagnetic waves.

  DESCRIPTION OF SYMBOLS 10 ... Vehicle, 11 ... Vehicle side control part (control apparatus), 13 ... Battery unit, 14 ... Motor, 15 ... Secondary coil (power receiving part), 20 ... Electronic key, 30 ... Charging apparatus (external power source), 35 ... Primary coil (power transmission unit).

Claims (3)

In a wireless power transmission system for charging a battery of the vehicle by wirelessly transmitting power from a power transmission unit of an external power source to a power reception unit of the vehicle,
Human detection means for detecting that a person has approached the vehicle;
A wireless power transmission system comprising: a control device that suppresses transmission power from the power transmission unit to the power reception unit when it is detected that a person approaches the vehicle through the human detection unit. The wireless power transmission system of claim 1.
A portable device that is carried by the user and transmits a radio signal including information on whether or not the user is a medical device wearer;
The human detection means detects that the user has approached the vehicle when receiving the wireless signal from the portable device,
The control device transmits power from the power transmission unit to the power reception unit only when it recognizes that a user approaching the vehicle detected through the human detection means is a medical device wearer based on the received radio signal. Wireless power transmission system that suppresses power. The wireless power transmission system according to claim 2.
The wireless signal includes an ID code;
A wireless power transmission system that enables unlocking of a vehicle door when the control device recognizes the validity of an ID code included in the wireless signal.

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