JP2013132170A - Vehicle, non-contact power reception apparatus, non-contact transmission apparatus, non-contact feeding system, and non-contact power transmission method - Google Patents

Abstract

In a system capable of transmitting power between a power transmission device and a power reception device in a non-contact manner, power transmission from the power transmission device is limited in accordance with a decrease in transmission efficiency.
A non-contact power feeding system transmits power in a non-contact manner from a power transmission unit of a power transmission device to a power reception unit of a vehicle. Vehicle 100 includes a power storage device 190 and can charge the power storage device using the power received by power reception unit 110. When the transmission efficiency of the power transmitted from power transmission device 200 exceeds the first threshold, vehicle ECU 300 permits execution of power transmission from power transmission unit 220, and the transmission efficiency is lower than the first threshold. When the threshold value is below 2, the power transmission from the power transmission unit 220 is not executed.
[Selection] Figure 2

Description

  The present invention relates to a vehicle, a non-contact power receiving device, a non-contact power transmission device, a non-contact power feeding system, and a non-contact power transmission method, and more particularly to a technique for transmitting power from a power transmission device to a power receiving device in a non-contact manner.

  In recent years, non-contact wireless power transmission without using a power cord or a power transmission cable has attracted attention, and an electric vehicle, a hybrid vehicle, or the like that can charge an in-vehicle power storage device with a power source outside the vehicle (hereinafter also referred to as “external power source”). Application to is proposed.

  Japanese Patent Laying-Open No. 2010-119246 (Patent Document 1) determines whether or not the transmission efficiency from the power transmission apparatus to the power reception apparatus is equal to or higher than a predetermined specified value in such non-contact power transmission, and the transmission efficiency. When power transmission is temporarily less than this specified value, the power transmission is temporarily stopped, and then the power transmission is resumed when the transmission efficiency is restored to the specified value or more by power transmission of minute power periodically. Is disclosed.

JP 2010-119246 A

  In Japanese Patent Application Laid-Open No. 2010-119246 (Patent Document 1), during power transmission, it is possible to stop and restart power feeding based on a decrease in power transmission efficiency due to the presence or absence of an obstacle in the power transmission area. can do.

  By the way, in such non-contact electric power feeding, it is known that transmission efficiency will be influenced by the positional relationship (distance etc.) between a power transmission apparatus and a power receiving apparatus. For this reason, when a passenger gets out of a vehicle or loads and unloads a load while performing a power feeding operation, the distance between the power transmission device and the power reception device fluctuates, resulting in a decrease in transmission efficiency. There is. In Japanese Patent Application Laid-Open No. 2010-119246 (Patent Document 1), there is a possibility that the power supply operation may be stopped even when there is a change in transmission efficiency due to the user's operation during such a power supply operation. There was a problem.

  The present invention has been made in order to solve such a problem, and an object of the present invention is to reduce transmission efficiency in a system in which power can be transmitted in a non-contact manner between a power transmission device and a power reception device. The power transmission from the power transmission device is limited according to the above. More preferably, it is determined whether or not power transmission from the power transmission apparatus is possible in consideration of a variation in transmission efficiency due to user operation.

  A non-contact power receiving device according to the present invention includes a power receiving unit that receives power in a non-contact manner from a power transmitting unit included in the power transmitting device, and a control device that can communicate with the power transmitting device. The control device transmits an instruction for switching execution and non-execution of power transmission from the power transmission device to the power transmission device based on information related to transmission efficiency of power transmitted from the power transmission device. The control device is configured so that the condition in the case of not executing power transmission from the power transmission device regarding information related to transmission efficiency is more relaxed than in the case of performing power transmission from the power transmission device. Features.

  Preferably, the control device permits execution of power transmission from the power transmission device when the transmission efficiency of the power transmitted from the power transmission device exceeds the first threshold value, and the transmission efficiency is lower than the first threshold value. When the value falls below the second threshold, power transmission from the power transmission device is not executed.

  Preferably, the second threshold value is an elapsed time when the elapsed time from one of the time when the transmission efficiency exceeds the first threshold and the time when power transmission from the power transmission apparatus is started is longer. Is set higher than when it is short.

  Preferably, the non-contact power receiving device is mounted on a vehicle. The control device sets the second threshold value to a higher value than when no occupant getting off from the vehicle is predicted when the occupant getting off from the vehicle is predicted.

  Preferably, the non-contact power receiving device is mounted on a vehicle. The control device sets the second threshold value to a value lower than the second threshold value when no occupant getting off from the vehicle is predicted when the occupant getting off from the vehicle is predicted.

  Preferably, the non-contact power receiving device is mounted on a vehicle. The control device does not execute power transmission based on the transmission efficiency when the passenger is expected to get off from the vehicle.

  Preferably, the control device transmits a predetermined power smaller than the power in the case of full-scale power transmission from the power transmission device before executing the full-scale power transmission from the power transmission device, and while the predetermined power is being transmitted. Whether or not full-scale power transmission can be executed is determined based on the transmission efficiency.

  Preferably, the control device stops power transmission from the power transmission device when the transmission efficiency falls below the second threshold while power transmission from the power transmission device is being executed.

  Preferably, the non-contact power receiving device is mounted on a vehicle. The vehicle includes an alarm device for notifying the user that the transmission efficiency has fallen below the second threshold.

  Preferably, the difference between the natural frequency of the power transmission unit and the natural frequency of the power reception unit is ± 10% or less of the natural frequency of the power transmission unit or the natural frequency of the power reception unit.

Preferably, the coupling coefficient between the power transmission unit and the power reception unit is 0.1 or less.
Preferably, the power receiving unit includes at least a magnetic field that vibrates at a specific frequency formed between the power receiving unit and the power transmitting unit, and an electric field that vibrates at a specific frequency formed between the power receiving unit and the power transmitting unit. The power is received from the power transmission unit through one side.

  A contactless power transmission device according to the present invention includes a power transmission unit that transmits power to a power reception unit included in the power reception device in a contactless manner, and a control device that controls power transmission to the power reception device. The control device switches execution and non-execution of power transmission to the power receiving device based on information related to transmission efficiency of power transmitted from the power transmission unit to the power receiving device. When the power transmission to the power receiving device is not executed, the control device relaxes the condition regarding information related to transmission efficiency, compared to the case where power transmission is executed.

  A vehicle according to the present invention is a vehicle capable of charging electric power received from a power transmission device in a contactless manner, and communication between the power reception unit that receives power in a contactless manner from a power transmission unit included in the power transmission device and the power transmission device. Possible control device. When the transmission efficiency of the power transmitted from the power transmission device exceeds the first threshold value, the control device permits execution of power transmission from the power transmission device, and the second transmission efficiency is lower than the first threshold value. When the value falls below the threshold, power transmission from the power transmission device is not executed. When it is predicted that the occupant will get off from the vehicle, the control device sets the second threshold value to a higher value than when the occupant does not get off from the vehicle.

  A non-contact power feeding system according to the present invention is a non-contact power feeding system that transmits power in a non-contact manner from a power transmission device to a vehicle, and includes a power transmission unit included in the power transmission device, a power reception unit included in the vehicle, and a power transmission device. A control device for controlling the power transmission operation. The control device switches execution and non-execution of power transmission from the power transmission device based on information related to transmission efficiency of power transmitted from the power transmission device. When the control device does not execute power transmission from the power transmission device, the control device relaxes conditions regarding information related to transmission efficiency, compared to the case where power transmission from the power transmission device is executed.

  A method according to the present invention is a method for transmitting and receiving power in a contactless manner between a power transmission device and a power reception device, and obtaining information related to transmission efficiency of power transmitted from the power transmission device to the power reception device; The step of switching execution and non-execution of power transmission from the power transmission device and the condition for information related to transmission efficiency more than when power transmission from the power transmission device is executed when the power transmission from the power transmission device is not executed. Mitigating steps.

  ADVANTAGE OF THE INVENTION According to this invention, in the system which can transmit electric power by non-contact between a power transmission apparatus and a power receiving apparatus, the power transmission from a power transmission apparatus can be restrict | limited according to the fall of transmission efficiency.

1 is an overall configuration diagram of a vehicle power supply system 10 according to a first embodiment of the present invention. It is a functional block diagram explaining the structure of the vehicle and power transmission apparatus which are shown in FIG. 1 in detail. FIG. 5 is another example of a functional block diagram illustrating in detail the configuration of the vehicle and the power transmission device shown in FIG. 1. It is an equivalent circuit diagram at the time of power transmission from the power transmission device to the vehicle. It is a figure which shows the simulation model of an electric power transmission system. It is a figure which shows the relationship between the shift | offset | difference of the natural frequency of a power transmission part and a power receiving part, and power transmission efficiency. It is a graph which shows the relationship between the electric power transmission efficiency when changing an air gap in the state which fixed the natural frequency, and the frequency of the electric current supplied to a power transmission part. It is the figure which showed the relationship between the distance from an electric current source (magnetic current source), and the intensity | strength of an electromagnetic field. FIG. 6 is a diagram for describing a power transmission operation restriction method based on transmission efficiency in the first embodiment. 4 is a functional block diagram for explaining power transmission control executed in the first embodiment. FIG. 4 is a flowchart for illustrating details of power transmission control processing executed in the first embodiment. 10 is a flowchart for explaining details of power transmission control processing executed in the second embodiment. FIG. 10 is a first diagram for illustrating a threshold setting method for limiting power transmission operation in the second embodiment. FIG. 11 is a second diagram for illustrating a threshold setting method for restricting a power transmission operation in the third embodiment. 12 is a flowchart for illustrating details of power transmission control processing executed in the third embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Configuration of wireless power supply system]
FIG. 1 is an overall configuration diagram of a vehicle power feeding system according to an embodiment of the present invention. Referring to FIG. 1, vehicle power feeding system 10 includes a vehicle 100 and a power transmission device 200. Vehicle 100 includes a power reception unit 110 and a communication unit 160. The power transmission device 200 includes a power supply device 210, a power transmission unit 220, and a communication unit 230.

  The power receiving unit 110 is installed on the bottom surface of the vehicle body, for example, and receives high-frequency AC power output from the power transmitting unit 220 of the power transmitting device 200 in a contactless manner via an electromagnetic field. The configuration of the power reception unit 110 will be described later together with the configuration of the power transmission unit 220 and power transmission from the power transmission unit 220 to the power reception unit 110. Communication unit 160 is a communication interface for vehicle 100 to communicate with power transmission device 200.

  The power supply apparatus 210 in the power transmission apparatus 200 generates AC power having a predetermined frequency. As an example, the power supply device 210 receives power from a system power supply (not shown), generates high-frequency AC power, and supplies the generated AC power to the power transmission unit 220.

  The power transmission unit 220 is installed, for example, on the floor of a parking lot and receives supply of high-frequency AC power from the power supply device 210. Then, power transmission unit 220 outputs electric power in a non-contact manner to power reception unit 110 of vehicle 100 via an electromagnetic field generated around power transmission unit 220. The configuration of the power transmission unit 220 will be described later together with the configuration of the power reception unit 110 and power transmission from the power transmission unit 220 to the power reception unit 110. Communication unit 230 is a communication interface for power transmission device 200 to communicate with vehicle 100.

  In the vehicle power supply system 10, power is transmitted in a non-contact manner from the power transmission unit 220 of the power transmission device 200 to the power reception unit 110 of the vehicle 100. In order to efficiently transmit power from the power transmission device 200 to the vehicle 100, it is necessary to accurately align the power reception unit 110 and the power transmission unit 220.

  FIG. 2 is a detailed configuration diagram of the vehicle power supply system 10 shown in FIG. Referring to FIG. 2, power transmission device 200 includes power supply device 210 and power transmission unit 220 as described above. In addition to communication unit 230, power supply device 210 further includes a power transmission ECU 240 that is a control device, a power supply unit 250, and a matching unit 260. The power transmission unit 220 includes a resonance coil 221, a capacitor 222, and an electromagnetic induction coil 223.

  Power supply unit 250 is controlled by control signal MOD from power transmission ECU 240, and converts power received from an AC power supply such as commercial power supply 400 into high-frequency power. Then, the power supply unit 250 supplies the converted high frequency power to the electromagnetic induction coil 223 via the matching unit 260.

  In addition, power supply unit 250 outputs power transmission voltage Vtr and power transmission current Itr detected by a voltage sensor and a current sensor (not shown) to power transmission ECU 240, respectively.

  Matching device 260 is a circuit for matching the impedance between power transmission device 200 and vehicle 100. Matching device 260 is provided between power supply unit 250 and power transmission unit 220 and is configured to be able to change the internal impedance. As an example, the matching device 260 includes a variable capacitor and a coil (not shown), and the impedance can be changed by changing the capacitance of the variable capacitor. By changing the impedance in the matching device 260, the impedance of the power transmission device 200 can be matched with the impedance of the vehicle 100 (impedance matching). In FIG. 2, matching unit 260 is described as a configuration provided separately from power supply unit 250, but power supply unit 250 may include the function of matching unit 260.

  The resonance coil 221 transfers electric power to the resonance coil 111 included in the power reception unit 110 of the vehicle 100 in a non-contact manner. Note that power transmission between the power reception unit 110 and the power transmission unit 220 will be described later with reference to FIG.

  Communication unit 230 is a communication interface for performing wireless communication between power transmission device 200 and vehicle 100 as described above. The communication unit 230 receives vehicle information transmitted from the communication unit 160 on the vehicle 100 side and a signal instructing start and stop of power transmission, and outputs these information to the power transmission ECU 240. Communication unit 230 transmits information including power transmission voltage Vtr and power transmission current Itr from power transmission ECU 240 to vehicle 100.

  Although not shown in FIG. 1, the power transmission ECU 240 includes a CPU (Central Processing Unit), a storage device, and an input / output buffer, and inputs signals from each sensor and outputs control signals to each device. Each device in the power supply device 210 is controlled. Note that these controls are not limited to processing by software, and can be processed by dedicated hardware (electronic circuit).

  In addition to power receiving unit 110 and communication unit 160, vehicle 100 includes a charging relay CHR 170, a rectifier 180, a power storage device 190, a system main relay SMR 115, a power control unit PCU (Power Control Unit) 120, and a motor generator 130. Power transmission gear 140, drive wheel 150, vehicle ECU (Electronic Control Unit) 300 as a control device, user interface (I / F) 165, voltage sensor 195, and current sensor 196. Power reception unit 110 includes a resonance coil 111, a capacitor 112, and an electromagnetic induction coil 113.

  In this embodiment, an electric vehicle is described as an example of vehicle 100, but the configuration of vehicle 100 is not limited to this as long as the vehicle can travel using electric power stored in the power storage device. Other examples of the vehicle 100 include a hybrid vehicle equipped with an engine and a fuel cell vehicle equipped with a fuel cell.

  The resonance coil 111 receives power from the resonance coil 221 included in the power transmission device 200 in a contactless manner.

  Rectifier 180 rectifies AC power received from electromagnetic induction coil 113 via CHR 170 and outputs the rectified DC power to power storage device 190. For example, the rectifier 180 may include a diode bridge and a smoothing capacitor (both not shown). As the rectifier 180, a so-called switching regulator that performs rectification using switching control may be used. When the rectifier 180 is included in the power receiving unit 110, it is more preferable to use a static rectifier such as a diode bridge in order to prevent a malfunction of the switching element due to the generated electromagnetic field.

  The CHR 170 is electrically connected between the power receiving unit 110 and the rectifier 180. The CHR 170 is controlled by a control signal SE2 from the vehicle ECU 300, and switches between power supply from the power receiving unit 110 to the rectifier 180 and cutoff.

  The power storage device 190 is a power storage element configured to be chargeable / dischargeable. The power storage device 190 includes, for example, a secondary battery such as a lithium ion battery, a nickel metal hydride battery, or a lead storage battery, and a power storage element such as an electric double layer capacitor.

  The power storage device 190 is connected to the rectifier 180 and stores the power received by the power receiving unit 110 and rectified by the rectifier 180. The power storage device 190 is also connected to the PCU 120 via the SMR 115. Power storage device 190 supplies power for generating vehicle driving force to PCU 120. Further, power storage device 190 stores the electric power generated by motor generator 130. The output of power storage device 190 is, for example, about 200V.

  Although not shown in FIG. 2, when the power reception voltage and the charging voltage of the power storage device 190 are different, a power conversion device such as a DC-DC converter is provided between the rectifier 180 and the power storage device 190. You may make it provide.

  Although not shown, power storage device 190 is provided with a voltage sensor and a current sensor for detecting voltage VB of power storage device 190 and input / output current IB. These detection values are output to vehicle ECU 300. Vehicle ECU 300 calculates the state of charge of power storage device 190 (also referred to as “SOC (State Of Charge)”) based on voltage VB and current IB.

  SMR 115 is electrically connected between power storage device 190 and PCU 120. SMR 115 is controlled by control signal SE <b> 1 from vehicle ECU 300, and switches between supply and interruption of power between power storage device 190 and PCU 120.

  Although not shown, the PCU 120 includes a converter and an inverter. The converter is controlled by a control signal PWC from vehicle ECU 300 to convert the voltage from power storage device 190. The inverter is controlled by a control signal PWI from vehicle ECU 300 and drives motor generator 130 using electric power converted by the converter.

  Motor generator 130 is an AC rotating electric machine, for example, a permanent magnet type synchronous motor including a rotor in which permanent magnets are embedded.

  The output torque of motor generator 130 is transmitted to drive wheels 150 via power transmission gear 140 to cause vehicle 100 to travel. The motor generator 130 can generate electric power by the rotational force of the drive wheels 150 during the regenerative braking operation of the vehicle 100. Then, the generated power is converted by PCU 120 into charging power for power storage device 190.

  In a hybrid vehicle equipped with an engine (not shown) in addition to motor generator 130, necessary vehicle driving force is generated by operating this engine and motor generator 130 in a coordinated manner. In this case, the power storage device 190 can be charged using the power generated by the rotation of the engine.

  Communication unit 160 is a communication interface for performing wireless communication between vehicle 100 and power transmission device 200 as described above, and vehicle ECU 300 can communicate with power transmission device 200 via communication unit 160. it can. Communication unit 160 outputs vehicle information from vehicle ECU 300 to power transmission device 200. In addition, the communication unit 160 outputs a signal instructing start and stop of power transmission from the power transmission device 200 to the power transmission device 200.

  The user interface 165 inputs user operations and outputs information to the user. For example, the user interface 165 receives a command instructing the start of external charging by a user operation. In addition, the user interface 165 provides the user with information such as position information of the power reception unit 110 and the power transmission unit 220 and a charging state of the power storage device 190.

  Although not shown in FIG. 1, vehicle ECU 300 includes a CPU, a storage device, and an input / output buffer, and inputs a signal from each sensor and outputs a control signal to each device. Control. Note that these controls are not limited to processing by software, and can be processed by dedicated hardware (electronic circuit).

  The voltage sensor 195 is connected in parallel to the electromagnetic induction coil 113 and detects the received voltage Vre received by the power receiving unit 110. The current sensor 196 is provided on a power line connecting the electromagnetic induction coil 113 and the CHR 170, and detects the received current Ire. The detected power reception voltage Vre and power reception current Ire are transmitted to the vehicle UCU 300 and used for calculation of transmission efficiency as described later.

  2 shows a configuration in which the electromagnetic induction coils 113 and 223 are provided in the power receiving unit 110 and the power transmission unit 220, respectively, a configuration in which the electromagnetic induction coils 113 and 223 are not provided is also possible. . In this case, as shown in FIG. 3, in power transmission unit 220A, resonance coil 221 is directly connected to matching device 260, and in power reception unit 110A, resonance coil 111 is connected to rectifier 180 via CHR 170. .

[Principle of power transmission]
FIG. 4 is an equivalent circuit diagram when power is transmitted from the power transmission device 200 to the vehicle 100. Referring to FIG. 4, power transmission unit 220 of power transmission device 200 includes an electromagnetic induction coil 223, a resonance coil 221, and a capacitor 222.

  The electromagnetic induction coil 223 is provided, for example, substantially coaxially with the resonance coil 221 at a predetermined interval from the resonance coil 221. The electromagnetic induction coil 223 is magnetically coupled to the resonance coil 221 by electromagnetic induction, and supplies high frequency power supplied from the power supply device 210 to the resonance coil 221 by electromagnetic induction.

  The resonance coil 221 forms an LC resonance circuit together with the capacitor 222. As will be described later, an LC resonance circuit is also formed in the power receiving unit 110 of the vehicle 100. The difference between the natural frequency of the LC resonant circuit formed by the resonant coil 221 and the capacitor 222 and the natural frequency of the LC resonant circuit of the power receiving unit 110 is ± 10% or less of the natural frequency of the former or the latter. The resonance coil 221 receives electric power from the electromagnetic induction coil 223 by electromagnetic induction, and transmits the electric power to the power receiving unit 110 of the vehicle 100 in a non-contact manner.

  The electromagnetic induction coil 223 is provided to facilitate power feeding from the power supply device 210 to the resonance coil 221. The power supply device 210 is directly connected to the resonance coil 221 without providing the electromagnetic induction coil 223. Also good. The capacitor 222 is provided to adjust the natural frequency of the resonance circuit. When a desired natural frequency is obtained using the stray capacitance of the resonance coil 221, the capacitor 222 is not provided. Also good.

  Power receiving unit 110 of vehicle 100 includes a resonance coil 111, a capacitor 112, and an electromagnetic induction coil 113. The resonance coil 111 and the capacitor 112 form an LC resonance circuit. As described above, the natural frequency of the LC resonance circuit formed by the resonance coil 111 and the capacitor 112 and the natural frequency of the LC resonance circuit formed by the resonance coil 221 and the capacitor 222 in the power transmission unit 220 of the power transmission device 200. The difference is ± 10% of the former natural frequency or the latter natural frequency. Then, the resonance coil 111 receives power from the power transmission unit 220 of the power transmission device 200 in a non-contact manner.

  The electromagnetic induction coil 113 is provided, for example, substantially coaxially with the resonance coil 111 at a predetermined interval from the resonance coil 111. The electromagnetic induction coil 113 is magnetically coupled to the resonance coil 111 by electromagnetic induction, takes out the electric power received by the resonance coil 111 by electromagnetic induction, and outputs it to the electric load device 118. The electric load device 118 comprehensively represents electric devices after the rectifier 180 (FIG. 2).

  The electromagnetic induction coil 113 is provided to facilitate the extraction of electric power from the resonance coil 111, and the rectifier 180 may be directly connected to the resonance coil 111 without providing the electromagnetic induction coil 113. The capacitor 112 is provided to adjust the natural frequency of the resonance circuit. When a desired natural frequency is obtained using the stray capacitance of the resonance coil 111, the capacitor 112 is not provided. Also good.

  In the power transmission device 200, high-frequency AC power is supplied from the power supply device 210 to the electromagnetic induction coil 223, and power is supplied to the resonance coil 221 using the electromagnetic induction coil 223. Then, energy (electric power) moves from the resonance coil 221 to the resonance coil 111 through a magnetic field formed between the resonance coil 221 and the resonance coil 111 of the vehicle 100. The energy (electric power) moved to the resonance coil 111 is taken out using the electromagnetic induction coil 113 and transmitted to the electric load device 118 of the vehicle 100.

  As described above, in this power transmission system, the difference between the natural frequency of power transmission unit 220 of power transmission device 200 and the natural frequency of power reception unit 110 of vehicle 100 is the natural frequency of power transmission unit 220 or the specific frequency of power reception unit 110. It is ± 10% or less of the frequency. By setting the natural frequencies of the power transmission unit 220 and the power reception unit 110 in such a range, the power transmission efficiency can be increased. On the other hand, when the difference between the natural frequencies is larger than ± 10%, the power transmission efficiency is smaller than 10%, and the power transmission time becomes longer.

  In addition, the natural frequency of the power transmission unit 220 (power reception unit 110) means a vibration frequency when the electric circuit (resonance circuit) constituting the power transmission unit 220 (power reception unit 110) freely vibrates. In the electric circuit (resonance circuit) constituting the power transmission unit 220 (power reception unit 110), the natural frequency when the braking force or the electrical resistance is substantially zero is the resonance frequency of the power transmission unit 220 (power reception unit 110). Also called.

  Simulation results obtained by analyzing the relationship between the natural frequency difference and the power transmission efficiency will be described with reference to FIGS. 5 and 6. FIG. 5 is a diagram illustrating a simulation model of the power transmission system. FIG. 6 is a diagram illustrating the relationship between the deviation of the natural frequencies of the power transmission unit and the power reception unit and the power transmission efficiency.

  Referring to FIG. 5, the power transmission system 89 includes a power transmission unit 90 and a power reception unit 91. The power transmission unit 90 includes a first coil 92 and a second coil 93. The second coil 93 includes a resonance coil 94 and a capacitor 95 provided in the resonance coil 94. The power receiving unit 91 includes a third coil 96 and a fourth coil 97. The third coil 96 includes a resonance coil 99 and a capacitor 98 connected to the resonance coil 99.

  The inductance of the resonance coil 94 is defined as an inductance Lt, and the capacitance of the capacitor 95 is defined as a capacitance C1. Further, the inductance of the resonance coil 99 is an inductance Lr, and the capacitance of the capacitor 98 is a capacitance C2. When each parameter is set in this way, the natural frequency f1 of the second coil 93 is expressed by the following equation (1), and the natural frequency f2 of the third coil 96 is expressed by the following equation (2).

f1 = 1 / {2π (Lt × C1) ^1/2 } (1)
f2 = 1 / {2π (Lr × C2) ^1/2 } (2)
Here, when the inductance Lr and the capacitances C1 and C2 are fixed and only the inductance Lt is changed, the relationship between the deviation of the natural frequency of the second coil 93 and the third coil 96 and the power transmission efficiency is shown in FIG. Show. In this simulation, the relative positional relationship between the resonance coil 94 and the resonance coil 99 is fixed, and the frequency of the current supplied to the second coil 93 is constant.

  In the graph shown in FIG. 6, the horizontal axis indicates the deviation (%) of the natural frequency, and the vertical axis indicates the power transmission efficiency (%) at a constant frequency current. The deviation (%) in natural frequency is expressed by the following equation (3).

(Deviation of natural frequency) = {(f1−f2) / f2} × 100 (%) (3)
As is clear from FIG. 6, when the deviation (%) of the natural frequency is 0%, the power transmission efficiency is close to 100%. When the deviation (%) in natural frequency is ± 5%, the power transmission efficiency is about 40%. When the deviation (%) in natural frequency is ± 10%, the power transmission efficiency is about 10%. When the deviation (%) in natural frequency is ± 15%, the power transmission efficiency is about 5%. That is, the natural frequencies of the second coil 93 and the third coil 96 are set so that the absolute value (natural frequency difference) of the deviation (%) of the natural frequency falls within the range of 10% or less of the natural frequency of the third coil 96. It can be seen that the power transmission efficiency can be increased to a practical level by setting. Furthermore, when the natural frequency of the second coil 93 and the third coil 96 is set so that the absolute value of the deviation (%) of the natural frequency is 5% or less of the natural frequency of the third coil 96, the power transmission efficiency is further increased. This is more preferable. The simulation software employs electromagnetic field analysis software (JMAG (registered trademark): manufactured by JSOL Corporation).

  Referring again to FIG. 2, power transmission unit 220 of power transmission device 200 and power reception unit 110 of vehicle 100 are formed between power transmission unit 220 and power reception unit 110, and a magnetic field that vibrates at a specific frequency and power transmission Power is exchanged in a non-contact manner through at least one of an electric field that is formed between the unit 220 and the power receiving unit 110 and vibrates at a specific frequency. The coupling coefficient κ between the power transmission unit 220 and the power reception unit 110 is preferably 0.1 or less, and power is transmitted from the power transmission unit 220 to the power reception unit 110 by causing the power transmission unit 220 and the power reception unit 110 to resonate with each other by an electromagnetic field. Is transmitted.

  Here, a magnetic field having a specific frequency formed around the power transmission unit 220 will be described. The “magnetic field of a specific frequency” typically has a relationship with the power transmission efficiency and the frequency of the current supplied to the power transmission unit 220. First, the relationship between the power transmission efficiency and the frequency of the current supplied to the power transmission unit 220 will be described. The power transmission efficiency when power is transmitted from the power transmission unit 220 to the power reception unit 110 varies depending on various factors such as the distance between the power transmission unit 220 and the power reception unit 110. For example, the natural frequency (resonance frequency) of the power transmission unit 220 and the power reception unit 110 is f0, the frequency of the current supplied to the power transmission unit 220 is f3, and the air gap between the power transmission unit 220 and the power reception unit 110 is the air gap AG. And

  FIG. 7 is a graph showing the relationship between the power transmission efficiency when the air gap AG is changed and the frequency f3 of the current supplied to the power transmission unit 220 while the natural frequency f0 is fixed. Referring to FIG. 7, the horizontal axis indicates the frequency f3 of the current supplied to the power transmission unit 220, and the vertical axis indicates the power transmission efficiency (%). The efficiency curve L1 schematically shows the relationship between the power transmission efficiency when the air gap AG is small and the frequency f3 of the current supplied to the power transmission unit 220. As shown in the efficiency curve L1, when the air gap AG is small, the peak of power transmission efficiency occurs at frequencies f4 and f5 (f4 <f5). When the air gap AG is increased, the two peaks when the power transmission efficiency is increased change so as to approach each other. As shown in the efficiency curve L2, when the air gap AG is larger than the predetermined distance, the power transmission efficiency has one peak, and the power transmission efficiency is obtained when the frequency of the current supplied to the power transmission unit 220 is the frequency f6. Becomes a peak. When the air gap AG is further increased from the state of the efficiency curve L2, the peak of power transmission efficiency is reduced as shown by the efficiency curve L3.

  For example, the following method can be considered as a method for improving the power transmission efficiency. As a first technique, the frequency of the current supplied to the power transmission unit 220 is made constant in accordance with the air gap AG, and the capacitance of the capacitor 222 or the capacitor 112 is changed, so that the power transmission unit 220 and the power reception unit 110 can be changed. It is conceivable to change the power transmission efficiency characteristics between the two. Specifically, the capacitances of the capacitor 222 and the capacitor 112 are adjusted so that the power transmission efficiency reaches a peak in a state where the frequency of the current supplied to the power transmission unit 220 is constant. In this method, the frequency of the current flowing through the power transmission unit 220 and the power reception unit 110 is constant regardless of the size of the air gap AG. Note that, as a technique for changing the characteristics of the power transmission efficiency, a technique using the matching device 260 of the power transmission device 200 or a converter (not shown) provided between the rectifier 180 and the power storage device 190 in the vehicle 100 is used. It is also possible to adopt a technique to do so.

  The second method is a method of adjusting the frequency of the current supplied to the power transmission unit 220 based on the size of the air gap AG. For example, when the power transmission characteristic is the efficiency curve L1, a current having a frequency f4 or f5 is supplied to the power transmission unit 220. When the frequency characteristic is the efficiency curves L2 and L3, the current having the frequency f6 is supplied to the power transmission unit 220. In this case, the frequency of the current flowing through power transmission unit 220 and power reception unit 110 is changed in accordance with the size of air gap AG.

  In the first method, the frequency of the current flowing through the power transmission unit 220 is a fixed constant frequency, and in the second method, the frequency flowing through the power transmission unit 220 is a frequency that changes as appropriate depending on the air gap AG. A current having a specific frequency set so as to increase the power transmission efficiency is supplied to the power transmission unit 220 by the first method, the second method, or the like. When a current having a specific frequency flows through the power transmission unit 220, a magnetic field (electromagnetic field) that vibrates at a specific frequency is formed around the power transmission unit 220. The power receiving unit 110 receives power from the power transmitting unit 220 through a magnetic field that is formed between the power receiving unit 110 and the power transmitting unit 220 and vibrates at a specific frequency. Therefore, the “magnetic field oscillating at a specific frequency” is not necessarily a magnetic field having a fixed frequency. In the above example, focusing on the air gap AG, the frequency of the current supplied to the power transmission unit 220 is set, but the power transmission efficiency is the horizontal direction of the power transmission unit 220 and the power reception unit 110. The frequency changes due to other factors such as a deviation, and the frequency of the current supplied to the power transmission unit 220 may be adjusted based on the other factors.

  In the above description, an example in which a helical coil is used as the resonance coil has been described. However, when an antenna such as a meander line is used as the resonance coil, a current having a specific frequency flows in the power transmission unit 220. Thus, an electric field having a specific frequency is formed around the power transmission unit 220. And electric power transmission is performed between the power transmission part 220 and the power receiving part 110 through this electric field.

  In this power transmission system, power transmission and power reception efficiency are improved by using a near field (evanescent field) in which the “electrostatic magnetic field” of the electromagnetic field is dominant.

  FIG. 8 is a diagram showing the relationship between the distance from the current source (magnetic current source) and the intensity of the electromagnetic field. Referring to FIG. 8, the electromagnetic field is composed of three components. The curve k1 is a component that is inversely proportional to the distance from the wave source, and is referred to as a “radiated electromagnetic field”. A curve k2 is a component inversely proportional to the square of the distance from the wave source, and is referred to as an “induction electromagnetic field”. The curve k3 is a component inversely proportional to the cube of the distance from the wave source, and is referred to as an “electrostatic magnetic field”. When the wavelength of the electromagnetic field is “λ”, the distance at which the strengths of “radiation electromagnetic field”, “induction electromagnetic field”, and “electrostatic magnetic field” are substantially equal can be expressed as λ / 2π.

  The “electrostatic magnetic field” is a region where the intensity of the electromagnetic wave suddenly decreases with the distance from the wave source. In the power transmission system according to this embodiment, the near field (evanescent field) in which the “electrostatic magnetic field” is dominant. ) Is used to transmit energy (electric power). That is, in the near field where the “electrostatic magnetic field” is dominant, by resonating the power transmitting unit 220 and the power receiving unit 110 (for example, a pair of LC resonance coils) having adjacent natural frequencies, the power receiving unit 220 and the other power receiving unit are resonated. Energy (electric power) is transmitted to 110. Since this “electrostatic magnetic field” does not propagate energy far away, the resonance method transmits power with less energy loss than electromagnetic waves that transmit energy (electric power) by “radiant electromagnetic field” that propagates energy far away. be able to.

  Thus, in this power transmission system, power is transmitted between the power transmission unit 220 and the power reception unit 110 in a non-contact manner by causing the power transmission unit 220 and the power reception unit 110 to resonate (resonate) with each other by an electromagnetic field. . And the coupling coefficient ((kappa)) between the power transmission part 220 and the power receiving part 110 becomes like this. Preferably it is 0.1 or less. Note that the coupling coefficient (κ) is not limited to this value, and may take various values that improve power transmission. Generally, in power transmission using electromagnetic induction, the coupling coefficient (κ) between the power transmission unit and the power reception unit is close to 1.0.

  Note that the coupling between the power transmitting unit 220 and the power receiving unit 110 in the power transmission is, for example, “magnetic resonance coupling”, “magnetic field (magnetic field) resonance coupling”, “electromagnetic field (electromagnetic field) resonant coupling”, “ Electric field (electric field) resonance coupling ". The “electromagnetic field (electromagnetic field) resonance coupling” means a coupling including any of “magnetic resonance coupling”, “magnetic field (magnetic field) resonance coupling”, and “electric field (electric field) resonance coupling”.

  When the power transmission unit 220 and the power reception unit 110 are formed by coils as described above, the power transmission unit 220 and the power reception unit 110 are mainly coupled by a magnetic field (magnetic field), and are referred to as “magnetic resonance coupling” or “magnetic field”. (Magnetic field) resonance coupling "is formed. For example, an antenna such as a meander line may be employed for the power transmission unit 220 and the power reception unit 110. In this case, the power transmission unit 220 and the power reception unit 110 are mainly based on an electric field (electric field). The “electric field (electric field) resonance coupling” is formed.

  In such a non-contact power supply system, even when a foreign object or a small animal enters between the power transmission unit and the power reception unit, the resonance frequency can vary and the transmission efficiency can change due to the impedance change. And when such a foreign material etc. intervene, if the foreign material is a metal body, for example, there exists a possibility of generating heat at the time of electric power transmission.

  On the other hand, when the transmission efficiency is reduced to a predetermined reference value or less during power transmission, a technique may be used to prevent the influence when a foreign object enters by stopping power transmission.

  As described above, the transmission efficiency varies depending on the distance between the power transmission unit in the power transmission device and the power reception unit in the power reception device (vehicle). When the power receiving unit as shown in FIG. 1 is provided at the bottom of the vehicle, the vehicle height fluctuates due to a load change caused by the passenger getting on and off the vehicle or loading and unloading the luggage. The distance of can vary. For this reason, even if the user stops the vehicle at a predetermined charging position where the transmission efficiency is relatively high, the transmission efficiency decreases due to the user's operation such as getting off after the vehicle stops, thereby causing unintended power transmission. It may cause a stoppage.

  In particular, when the start of charging the power storage device is operated in the vehicle, there is a high possibility that the transmission efficiency varies as described above during power transmission.

  Therefore, in the present embodiment, in the non-contact power supply system, the reduction in transmission efficiency during power transmission is considered while taking into account the reduction in transmission efficiency that may occur due to the occupant's operation after the start of power transmission from the power transmission device. Accordingly, a method for determining whether or not power transmission from the power transmission device is possible is executed.

  In the following embodiments, a case where transmission efficiency is used as a parameter will be described as an example. However, as other parameters related to transmission efficiency, received power on the vehicle side or reflected power detectable on the power transmission device side is used. It may be used.

[Embodiment 1]
FIG. 9 is a diagram for explaining a power transmission operation limiting method based on transmission efficiency in the first embodiment. In FIG. 9, the horizontal axis represents time, and the vertical axis represents transmission efficiency. Moreover, the solid line W10 in FIG. 9 shows an example of a variation in transmission efficiency from the power transmission unit to the power reception unit, which is determined based on the distance between the power transmission unit and the power reception unit.

  Referring to FIG. 9, the period until time t2 is a period in which the user is stopping the vehicle to a predetermined stop position for charging, and the power transmission efficiency increases as the vehicle approaches the stop position. To do.

  At time t1, the transmission efficiency exceeds the threshold Eth1 for permitting the start of power transmission, thereby permitting execution of power transmission.

  In response to the fact that the execution of power transmission is permitted, the user completes the stop of the vehicle at time t2. Thereafter, a charging operation is instructed by the user's operation, and power transmission from the power transmission device is started (time t3).

  However, when the user gets off at time t4 after the start of power transmission, the vehicle height may vary due to a change in the load applied to the vehicle, and the transmission efficiency may decrease as indicated by the solid line W10. As a result, the transmission efficiency falls below the threshold Eth1.

  In the first embodiment, a power transmission stop accompanying a decrease in transmission efficiency during the power transmission operation is determined by another threshold Eth2 lower than the threshold Eth1 that permits the above power transmission start. When the transmission efficiency falls below the threshold Eth2, the charging operation and the power transmission operation are stopped. Therefore, even if the transmission efficiency falls below the threshold Eth1 during power transmission, the power transmission operation is continued if the transmission efficiency exceeds the threshold Eth2, so unintentional power transmission stoppage that may occur due to passengers getting on and off during charging, etc. Can be suppressed.

  In the example of FIG. 9, the transmission efficiency lowered due to the passenger getting off exceeds the threshold Eth <b> 2, so the power transmission operation is not stopped. However, at time t5, when the transmission efficiency is further reduced and falls below the threshold Eth2 due to some foreign matter entering between the power transmission unit and the power reception unit, the power transmission operation is stopped at that time (FIG. 9 at time t6).

  Here, the threshold value Eth2 for determining stoppage of power transmission may be a fixed value. However, as indicated by the broken line W20 in FIG. 9, the longer the elapsed time from the start of power transmission or the start of power transmission, It is preferable to set it variably so as to be higher than when the elapsed time is short. If the charging execution period becomes longer, the possibility that the occupant remains in the vehicle is reduced, so that the transmission efficiency is less likely to change due to the raising and lowering of the occupant. And the fall of the transmission efficiency which arises in this case has the high possibility of the entrance of the foreign material in the electromagnetic field under the above power transmission operation execution, and its vicinity. Therefore, when the elapsed time from the start of power transmission or the vehicle stop is long, the power transmission operation can be appropriately stopped with respect to the entry of foreign matter by increasing the sensitivity of the power transmission stop due to the decrease in transmission efficiency.

  Note that the temporal change in the threshold value Eth2 is not limited to a linear increase as indicated by a broken line W20 in FIG. 9, but may be a case where the threshold Eth2 increases in a curved line or a stepwise manner. . Furthermore, an upper limit value for the threshold value Eth2 may be provided.

  In addition to the actual time, the elapsed time is not limited to the actual time. For example, a predetermined series of operations are completed after the start of charging, or an operation performed by the user on the vehicle from outside the vehicle (for example, a door lock operation). ), Etc., including situations where the elapsed time can be assumed to be long.

  FIG. 10 is a functional block diagram for explaining power transmission control executed in the first embodiment. Each functional block described in the functional block diagram illustrated in FIG. 10 is realized by hardware or software processing by vehicle ECU 300.

  In the following description, a case where the control of the present embodiment is executed by the vehicle ECU 300 of the vehicle 100 will be described as an example, but the control can also be executed by the power transmission ECU 240 on the power transmission device 200 side. .

  Referring to FIGS. 2 and 10, vehicle ECU 300 includes a transmission efficiency calculation unit 310, a threshold calculation unit 320, a determination unit 330, a charge control unit 340, and an alarm output unit 350.

  Transmission efficiency calculation unit 310 receives power transmission voltage Vtr and power transmission current Itr received from power transmission device 200. Further, the transmission efficiency calculation unit 310 receives the received voltage Vre and the received current Ire detected by the voltage sensor 195 and the current sensor 196, respectively. The transmission efficiency calculation unit 310 calculates the transmission efficiency EFF represented by the ratio of the received power to the transmitted power from these pieces of information. Then, the transmission efficiency calculation unit 310 outputs the calculated transmission efficiency EFF to the threshold value calculation unit 320 and the determination unit 330.

  Threshold value calculation unit 320 uses threshold value Eth (Eth1, Eth2) for use in determination unit 330 based on transmission efficiency EFF calculated by transmission efficiency calculation unit 310, a signal indicating the start of power transmission, or the like. ) And the calculated threshold value Eth is output to the determination unit 330.

  Determination unit 330 receives transmission efficiency EFF from transmission efficiency calculation unit 310 and threshold value Eth from threshold value calculation unit 320. Determination unit 330 optionally receives a signal SIG indicating that an occupant has exited and / or that a load has been unloaded.

  Based on these pieces of information, determination unit 330 compares transmission efficiency EFF and threshold value Eth to determine whether or not power storage operation of power storage device 190 is possible. Then, determination unit 330 outputs determination flag FLG, which is the determination result, to charge control unit 340 and alarm output unit 350.

  Charging control unit 340 receives determination flag FLG from determination unit 330 and SOC of power storage device 190. When power transmission from the power transmission device 200 is permitted by the determination flag FLG, the charging control unit 340 transmits a power transmission start signal CHG to the power transmission device 200 based on the SOC, and CHR170 by the control signal SE2. Is set to the conductive state, and the charging operation of the power storage device 190 is executed.

  On the other hand, if the determination flag FLG indicates that power transmission from the power transmission device 200 is restricted, the charging control unit 340 stops power transmission if power transmission is being performed, and indicates that state if power transmission is not performed. To maintain.

  Alarm output unit 350 receives determination flag FLG from determination unit 330. When the alarm output unit 350 detects that the power transmission operation has been stopped halfway based on the change in the determination flag FLG, the user I / F 165 informs the user that the power transmission has been stopped by the control signal ALM. Notice. The notification to the user includes a visual notification such as a lamp and a screen display, and an audible notification such as a buzzer, a chime, and a voice alarm.

  FIG. 11 is a flowchart for illustrating the details of the charging control process in the first embodiment. The flowchart described later with reference to FIG. 11 and FIGS. 12 and 14 is realized when a program stored in advance in the vehicle ECU 300 (or the power transmission ECU 240) is called from the main routine and executed in a predetermined cycle. . Alternatively, for some steps, it is also possible to construct dedicated hardware (electronic circuit) and realize processing.

  Referring to FIGS. 2 and 11, vehicle ECU 300 determines in step (hereinafter, step is abbreviated as S) 100 whether or not charging start command STRT based on a user operation or the like has been received.

  If the charging start command has not been received (NO in S100), there is no need to perform the control, so vehicle ECU 300 skips the subsequent processing and ends the processing.

  If the charging start command is received (YES in S100), the process proceeds to S110, and vehicle ECU 300 outputs a test power transmission start command to power transmission device 200. The test power transmission is to perform power transmission using a smaller power than when power is transmitted from the power transmission device 200 in earnest, and the power transmission device 200 executes the test power transmission in response to the test power transmission start command. . Although not shown in FIG. 11, at this time, the vehicle ECU 300 causes the CHR 170 to be in a conductive state so that a current flows through a circuit including the electromagnetic induction coil 113.

  The above-mentioned “full-scale power transmission” refers to the power level set in step S140, that is, the power level when performing a normal charging operation when the condition of step S130 described below is satisfied. It means transmitting electricity.

  Then, in S120, vehicle ECU 300 uses power transmission voltage Vtr and power transmission current Itr transmitted from communication unit 230 of power transmission device 200, and voltage sensor 195 and current sensor 196, respectively, during test power transmission. Power transmission efficiency EFF is calculated using detected power reception voltage Vre and power reception current Ire. The transmission efficiency EFF is calculated, for example, as in the following formula (4).

Transmission efficiency EFF (%) = {(Vre × Ire) / (Vtr × Itr)} × 100
(4)
Note that the transmission efficiency EFF may be calculated using reflected power detected by the power transmission device 200.

  Next, in step S130, the vehicle ECU 300 determines whether or not the transmission efficiency calculated in step S120 is greater than a threshold value Eth1 that enables (permits) the start of power transmission.

  When transmission efficiency is equal to or lower than threshold value Eth1 (NO in S130), power transmission is not permitted. Therefore, vehicle ECU 300 advances the process to S190, outputs an alarm, and transmission efficiency is low, so power transmission is not permitted. This is notified to the user. In addition to this, a message or voice announcement that prompts the user to correct the vehicle stop position may be output.

  Thereafter, the process proceeds to S180, and vehicle ECU 300 outputs a command for stopping test power transmission to power transmission device 200.

  On the other hand, when transmission efficiency is greater than threshold value Eth1 (YES in S130), the process proceeds to S140, and vehicle ECU 300 increases the transmission power to a level at which full-scale power transmission of power storage device 190 is executed. Is output to the power transmission device 200. In addition, vehicle ECU 300 performs a charging operation of power storage device 190 together with this.

  In step S150, vehicle ECU 300 calculates the power transmission efficiency while the power transmission operation is being performed. In step S160, vehicle ECU 300 determines whether the transmission efficiency is greater than threshold value Eth2 (<Eth1) at which power transmission should be stopped. Determine whether. Note that the threshold Eth2 may be a fixed value, or may be changed according to the time from the start of power transmission, as described with reference to FIG.

  If transmission efficiency is greater than threshold value Eth2 (YES in S160), vehicle ECU 300 proceeds to S170 while continuing the power transmission operation, and determines whether or not the charging completion condition is satisfied.

  The charging completion conditions include, for example, that the power storage device 190 is in a fully charged state, that the charging end time has been reached when timer charging is being performed, that the midnight discount time zone for power has ended, and / or Or it includes the occurrence of an abnormality in the system.

  If the charging completion condition is not satisfied (NO in S170), the process is returned to S150, and vehicle ECU 300 continues the charging operation.

  If the charging completion condition is satisfied (YES in S170), the process proceeds to S180, and vehicle ECU 300 outputs a command to stop power transmission to power transmission device 200 and performs charging operation with CHR 170 in a non-conduction state. Exit.

  Further, in S160, for example, when a power transmission operation is being performed, passengers get on and off, load and unload, or foreign objects or small animals enter between the power transmission unit 220 and the power reception unit 110, thereby improving transmission efficiency. If it has decreased to threshold value Eth2 or less (NO in S160), the process proceeds to S190. In S190, vehicle ECU 300 outputs a warning to notify the user that the transmission efficiency has decreased, and stops power transmission from power transmission device 200 in S180.

  Although not shown in the figure, the power transmission apparatus 200 responds to the fact that the transmission efficiency is restored to a predetermined level (for example, the threshold Eth2) again after the power transmission is stopped due to the decrease in the transmission efficiency. It is also possible to resume the power transmission from the power supply and continue charging the power storage device 190.

  By performing control according to the processing as described above, in a system in which power can be transmitted in a non-contact manner between the power transmission device and the power reception device, power transmission from the power transmission device can be limited in accordance with a decrease in transmission efficiency. it can. And, by setting the threshold value (Eth2) to stop power transmission smaller than the threshold value (Eth1) of transmission efficiency that permits the start of power transmission, along with passengers getting on and off and loading and unloading luggage, It is possible to reduce the possibility of power transmission stop unintended by the user.

  In the above description, in S160, the stop of power transmission is determined based on whether or not the absolute value of the transmission efficiency is equal to or less than the predetermined threshold Eth2, but instead of this, the transmission efficiency at the time of starting power transmission is determined. The stoppage of power transmission may be determined based on whether or not the “amount of decrease in transmission efficiency” exceeds a predetermined threshold.

[Embodiment 2]
In the first embodiment, a configuration has been described in which a decrease in transmission efficiency is determined at the same level before and after a passenger gets off.

  However, for example, in the case of charging at midnight by timer charging, since the passenger has already got off the vehicle, a large change in transmission efficiency is unlikely to occur. However, as described in the first embodiment, there is a possibility that a change in transmission efficiency may occur due to the entry of foreign matter between the power transmission unit and the power reception unit. It is desirable to quickly limit power transmission in order to prevent the generation of extraneous foreign matter.

  Therefore, in the second embodiment, when occupant getting off is predicted, a threshold value (Eth2) for limiting power transmission is set higher than that when occupant getting off is not predicted, and transmission efficiency is improved. A configuration in which power transmission is appropriately limited even when the amount of decrease is smaller will be described.

  FIG. 12 is a flowchart for explaining details of the power transmission control process executed in the second embodiment. FIG. 12 is obtained by adding steps S155, S156, and S157 to the flowchart described in FIG. 11 of the first embodiment. In FIG. 12, the description of the same steps as those in FIG. 11 will not be repeated.

  Referring to FIG. 2 and FIG. 12, when the power transmission efficiency is larger than threshold value Eth1 in test power transmission (YES in S130) and transmission power is increased and full-scale power transmission is started (S140), the vehicle In S150, ECU 300 calculates the transmission efficiency while performing full-scale power transmission.

  Next, in S155, the vehicle ECU 300 determines whether or not the passenger is expected to get off. The determination as to whether or not the passenger is expected to get off is performed based on, for example, a detection value of a load sensor (not shown) provided on the seat, whether or not the door is opened and closed, and the like. In addition to the passenger, it may be additionally determined whether the loading / unloading of the luggage is completed by opening / closing the trunk or changing the load in the trunk. Further, it may be estimated that a predetermined time has elapsed since the start of charging.

  If the passenger is not expected to get off (NO in S155), the process proceeds to S156, and vehicle ECU 300 sets threshold value Eth2 to α. The threshold value Eth2 (= α) in this case corresponds to the threshold value Eth2 in the first embodiment.

  On the other hand, when the passenger is expected to get off (NO in S155), the process proceeds to S157, and vehicle ECU 300 sets threshold Eth2 to β (> α) higher than α.

  This threshold value Eth2 may be switched in response to the prediction of the passenger getting off as shown in FIG. 13 while being constant with respect to time, or when the threshold value Eth2 is changed with time as shown in FIG. Alternatively, a bias may be added in response to the prediction of the passenger getting off (broken line W31 in FIG. 14) or the inclination may be increased (broken line W32 in FIG. 14).

  Thereafter, vehicle ECU 300 compares transmission efficiency with threshold value Eth2 set in S156 or S157 in S160, and determines whether to continue or stop the power transmission operation as in the first embodiment.

  By performing control according to the above processing, in the non-contact power supply system, it is determined whether or not power transmission is possible in consideration of fluctuations in transmission efficiency caused by user operations such as passengers getting on and off and loading and unloading of luggage. Is possible.

[Embodiment 3]
For example, when non-contact charging is performed in an indoor parking lot at home, the possibility that a foreign object enters between the power transmission unit and the power reception unit during power transmission may be very low. And if a passenger's getting off is already completed, the necessity of performing the calculation of a transmission efficiency and the process of a comparison tends to become low. Therefore, in the third embodiment, a configuration will be described in which, when it is confirmed that the passenger has exited the vehicle, it is not determined whether or not power transmission is possible based on the transmission efficiency thereafter. As described above, there is an advantage that the processing load of the control device can be reduced by relaxing the condition for limiting the power transmission based on the transmission efficiency according to the completion of the passenger getting off.

  FIG. 15 is a flowchart for explaining details of the power transmission control process executed in the third embodiment. FIG. 15 is obtained by adding steps S155A and S175 to the flowchart described in FIG. 11 of the first embodiment. In FIG. 15, the description of the same steps as those in FIG. 11 will not be repeated.

  Referring to FIGS. 2 and 15, when the power transmission efficiency is greater than threshold value Eth1 in test power transmission (YES in S130) and transmission power is increased and full-scale power transmission is started (S140), the vehicle In S150, ECU 300 calculates the transmission efficiency while performing full-scale power transmission.

  Next, in S155A, vehicle ECU 300 determines whether or not the passenger is expected to get off. The determination as to whether or not the passenger is expected to get off is the same as that described in S155 in the second embodiment.

  If the occupant is not expected to get off (NO in S155A), that is, if the occupant is still in the vehicle, the distance between the power transmission unit 220 and the power reception unit 110 varies due to the movement of the occupant in the vehicle or the getting off of the vehicle. Variations in efficiency can occur. Therefore, vehicle ECU 300 advances the process to S160, compares the calculated transmission efficiency with threshold value Eth2, and reduces the transmission efficiency to threshold value Eth2 or less, as described in the first embodiment. If so (NO in S160), an alarm is output (S190) to stop power transmission (S180).

  On the other hand, when the passenger is expected to get off (YES in S155A), the process proceeds to S175, and vehicle ECU 300 determines whether the charging completion condition is satisfied. The charging completion conditions in S175 are the same as the conditions in S170 described in the first embodiment.

  If the charging completion condition has not yet been satisfied (NO in S175), the process returns to S175, and vehicle ECU 300 continues the power transmission operation until the charging completion condition is satisfied without considering transmission efficiency.

  If the charging completion condition is satisfied (YES in S175), the process proceeds to S180, and vehicle ECU 300 stops power transmission from power transmission device 200 and stops the charging operation of power storage device 190.

  By performing the control according to the above processing, in the non-contact power supply system, taking into account transmission efficiency fluctuations caused by user actions such as passengers getting on and off and loading and unloading luggage, Whether it is possible or not can be determined.

  As described above, when the occupant's getting off is predicted, the transmission efficiency is not taken into consideration (that is, the threshold Eth2 = 0). The value Eth2 may be relaxed by setting the value Eth2 to be smaller than a threshold value when the passenger is not expected to get off.

  Alternatively, the passenger getting off may be detected, and the charging efficiency that is lower than the actual charging efficiency when the passenger got off by a predetermined value may be set as the threshold Eth2.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  10, 10A vehicle power supply system, 89 power transmission system, 90, 220, 220A power transmission unit, 91, 110, 110A power reception unit, 92, 93, 96, 97 coil, 94, 99, 111, 221 resonance coil, 95, 98 , 112, 222 capacitor, 100, 100A vehicle, 113, 223 electromagnetic induction coil, 115 SMR, 118 electric load device, 120 PCU, 130 motor generator, 140 power transmission gear, 150 driving wheel, 160, 230 communication unit, 165 user Interface, 170 CHR, 180 rectifier, 190 power storage device, 195 voltage sensor, 196 current sensor, 200, 200A power transmission device, 210 power supply device, 240 power transmission ECU, 250 power supply unit, 260 matching unit, 300 vehicle ECU, 310 transmission effect Rate calculation unit, 320 threshold value calculation unit, 330 determination unit, 340 charge control unit, 350 alarm output unit, 400 commercial power supply.

Claims (16)

A non-contact power receiving device that receives power from a power transmission device in a non-contact manner,
A power receiving unit that receives power in a non-contact manner from a power transmission unit included in the power transmission device;
A control device capable of communicating with the power transmission device,
The control device transmits an instruction for switching execution and non-execution of power transmission from the power transmission device to the power transmission device based on information related to transmission efficiency of power transmitted from the power transmission device,
The control device is configured such that a condition in the case where power transmission from the power transmission device is not executed regarding information related to the transmission efficiency is relaxed compared to a case where power transmission from the power transmission device is executed. A non-contact power receiving device.   When the transmission efficiency of the power transmitted from the power transmission device exceeds a first threshold value, the control device permits execution of power transmission from the power transmission device, and the transmission efficiency is greater than the first threshold value. The non-contact power receiving device according to claim 1, wherein power transmission from the power transmission device is not executed when the value is lower than a lower second threshold value.   The second threshold is greater when the elapsed time from one of the time when the transmission efficiency exceeds the first threshold and the time when power transmission from the power transmission device is started is longer. The non-contact power receiving apparatus according to claim 2, wherein the non-contact power receiving apparatus is set to be higher than when the elapsed time is short. The non-contact power receiving device is mounted on a vehicle,
The said control apparatus sets a said 2nd threshold value to a higher value than the case where a passenger | crew's alighting is not estimated from the said vehicle, when a passenger | crew's alighting is estimated from the said vehicle, The said 2nd threshold value is set to a value higher than the case where a passenger | crew's alighting is not predicted from the said vehicle. The non-contact power receiving device described. The non-contact power receiving device is mounted on a vehicle,
The control device is configured to lower the second threshold value when the passenger is expected to get off from the vehicle, and to be lower than the second threshold value when the passenger is not expected to get off from the vehicle. The non-contact power receiving device according to claim 2, wherein The non-contact power receiving device is mounted on a vehicle,
The contactless power receiving device according to claim 1, wherein the control device does not perform power transmission based on the transmission efficiency when a passenger is expected to get off from the vehicle.   The control device transmits a predetermined power smaller than the power in the case of the full-scale power transmission from the power transmission device before the full-scale power transmission from the power transmission device is executed, and the predetermined power is transmitted. The contactless power receiving device according to claim 1, wherein whether or not full-scale power transmission can be executed is determined based on a transmission efficiency between the two.   The non-control unit according to claim 2, wherein the control device stops power transmission from the power transmission device when the transmission efficiency falls below the second threshold value while power transmission from the power transmission device is being performed. Contact power receiving device. The non-contact power receiving device is mounted on a vehicle,
The non-contact power receiving device according to claim 8, wherein the vehicle includes an alarm device for notifying a user that the transmission efficiency falls below the second threshold value.   The contactless power receiving device according to claim 1, wherein a difference between the natural frequency of the power transmission unit and the natural frequency of the power reception unit is ± 10% or less of the natural frequency of the power transmission unit or the natural frequency of the power reception unit.   The contactless power receiving device according to claim 1, wherein a coupling coefficient between the power transmitting unit and the power receiving unit is 0.1 or less.   The power reception unit includes a magnetic field that vibrates at a specific frequency formed between the power reception unit and the power transmission unit, and an electric field that vibrates at a specific frequency formed between the power reception unit and the power transmission unit. The non-contact power receiving apparatus according to claim 1, wherein the non-contact power receiving apparatus receives power from the power transmission unit through at least one of the above. A contactless power transmission device that supplies power to a power receiving device in a contactless manner,
A power transmission unit that transmits power in a non-contact manner to a power reception unit included in the power reception device;
A control device for controlling power transmission to the power receiving device,
The control device switches execution and non-execution of power transmission to the power receiving device based on information related to transmission efficiency of power transmitted from the power transmission unit to the power receiving device.
The control device is a non-contact power transmission device that relaxes conditions regarding information related to transmission efficiency when power transmission to the power receiving device is not performed than when power transmission is performed. A vehicle capable of charging electric power received in a non-contact manner from a power transmission device,
A power receiving unit that receives power in a non-contact manner from a power transmission unit included in the power transmission device;
A control device capable of communicating with the power transmission device,
When the transmission efficiency of the power transmitted from the power transmission device exceeds a first threshold value, the control device permits execution of power transmission from the power transmission device, and the transmission efficiency is greater than the first threshold value. Less than the lower second threshold value, the power transmission from the power transmission device is not executed,
The control device sets the second threshold value to a higher value than when no occupant getting off from the vehicle is predicted when the occupant getting off from the vehicle is predicted to be completed. A non-contact power supply system that transmits electric power from a power transmission device to a vehicle in a non-contact manner,
A power transmission unit included in the power transmission device;
A power receiving unit included in the vehicle;
A control device for controlling the power transmission operation from the power transmission device,
The control device switches execution and non-execution of power transmission from the power transmission device based on information related to transmission efficiency of power transmitted from the power transmission device,
In the non-execution of power transmission from the power transmission device, the control device relaxes a condition regarding information related to transmission efficiency, compared to a case of performing power transmission from the power transmission device. A method of transmitting and receiving electric power in a contactless manner between a power transmission device and a power reception device,
Obtaining information related to transmission efficiency of power transmitted from the power transmission device to the power reception device;
Switching execution and non-execution of power transmission from the power transmission device;
Relaxing the condition on information related to transmission efficiency more than executing power transmission from the power transmission device when power transmission from the power transmission device is not executed.

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