JP2014103823A - Power transmission device, power reception device, vehicle having power reception device and power transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize highly efficient power transmission by selecting a power transmission section closest to a power reception section of a power reception device in the case that a power transmission device includes a plurality of power transmission sections.SOLUTION: A power transmission ECU (Electronic Control Unit) 240 executes scan control for sequentially switching a plurality of power transmission sections 220 and determines a power transmission section used for power transmission to a power reception section 110 on the basis of a power transmission situation to the power reception section 110 at the time of executing the scan control. Impedance of a matching unit 215 is adjusted on the basis of a gap (car height) between the power transmission section used for power transmission to the power reception section 110 and the power reception section 110. At this point, the power transmission ECU 240 executes the scan control by setting the matching unit 215 to a state which should be adjusted when the gap is equal to or less than a predetermined value.

Description

  The present invention relates to a power transmission device, a power reception device, a vehicle including the power transmission device, and a power transmission system, and more particularly to a technique for transmitting power from the power transmission device to the power reception device in a contactless manner.

  Japanese Patent Laying-Open No. 2011-188733 (Patent Document 1) discloses a wireless power feeding system that wirelessly supplies power from a power feeding device to a moving body. In this wireless power feeding system, a plurality of antennas are provided on a power feeding device or a moving body. In the case where a plurality of antennas are provided in the power feeding device, the antenna of the power feeding device is selected according to the reception strength when radio waves are transmitted from each antenna of the power feeding device to the moving body. When a plurality of antennas are provided on the moving body, the antenna of the moving body is selected according to the reception intensity of each antenna of the moving body (see Patent Document 1).

JP 2011-188733 A JP 2012-34468 A

  However, in the above wireless power feeding system, for example, when a plurality of antennas (a plurality of power transmission units) are provided in the power feeding device, there is a possibility that the antenna of the power feeding device closest to the antenna (power receiving unit) of the mobile object may not be selected. is there.

  In other words, in a non-contact power transmission system, the impedance between the power transmission unit and the power reception unit varies depending on the distance between the power transmission unit and the power reception unit. It is important to perform impedance matching in a device or a power receiving device. For this reason, the power transmitting device and the power receiving device are generally provided with a matching unit for impedance matching.

  Here, depending on the setting of the matching unit, when there is no position shift between the power transmission unit and the power reception unit, the power transmission efficiency and the reception strength of the power reception unit are lower than when there is a position shift There is. In such a case, there is a possibility of selecting a power transmission unit farther than the power transmission unit closest to the power reception unit. However, considering that the power transmission efficiency from the selected power transmission unit to the power reception unit is adjusted after selection of the power transmission unit, the power transmission unit closest to the power reception unit is selected. However, such a problem is not particularly examined in the above patent document.

  Therefore, an object of the present invention is to provide a power transmission unit closest to the power receiving unit of the power receiving device when the power transmitting device includes a plurality of power transmitting units in the power transmission system that transmits power from the power transmitting device to the power receiving device in a contactless manner. To achieve high-efficiency power transmission.

  Another object of the present invention is to receive power closest to the power transmission unit of the power transmission device when the power reception device includes a plurality of power reception units in a power transmission system that transmits power from the power transmission device to the power reception device in a contactless manner. The part is selected to realize high-efficiency power transmission.

  According to this invention, the power transmission device is a power transmission device that supplies power to the power reception device, and includes a plurality of power transmission units, a control unit, and an impedance matching unit. The plurality of power transmission units are arranged on substantially the same plane, and each power transmission unit can output the power received from the power source to the power reception unit of the power receiving device in a non-contact manner. The control unit executes scan control for sequentially switching a plurality of power transmission units to transmit power to the power reception unit, and determines a power transmission unit used for power transmission to the power reception unit based on a power transmission state to the power reception unit at the time of scan control execution . The impedance matching unit adjusts the impedance based on the distance in the normal direction of the plane between the power transmission unit used for power transmission to the power reception unit and the power reception unit. Here, the control unit executes the scan control by setting the impedance matching unit in a state to be adjusted when the distance is equal to or less than a predetermined value. The predetermined value is a characteristic that the power transmission characteristic with respect to the positional deviation amount in the direction along the plane between the power transmission unit and the power receiving unit used for power transmission to the power receiving unit decreases in power transmission efficiency as the positional deviation amount increases. It is the said distance when showing.

  Preferably, the control unit sets the impedance matching device to a state to be adjusted when the distance is a predetermined minimum value, and executes scan control.

  Preferably, the control unit adjusts the impedance of the impedance matching unit based on the power transmission efficiency during power transmission from the power transmission unit to the power reception unit used for power transmission to the power reception unit after performing the scan control.

  Preferably, the power transmission device further includes a switch. The switch electrically connects one of the plurality of power transmission units to the power source and electrically disconnects the remaining power transmission units from the power source. The control unit sequentially switches the power transmission unit electrically connected to the power source by controlling the switch when the scan control is executed.

  Preferably, the difference between the natural frequency of the power transmission unit used for power transmission to the power reception 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 used for power transmission to the power reception unit is 0.3 or less.

  Preferably, the power transmission unit used for power transmission to the power reception unit receives power through at least one of a magnetic field formed between the power transmission unit and the power reception unit and an electric field formed between the power transmission unit and the power reception unit. Power to the department. A magnetic field and an electric field are formed between the power transmission unit and the power reception unit, and vibrate at a specific frequency.

  According to the invention, the power receiving device is a power receiving device that receives power from the power transmitting device, and includes a plurality of power receiving units, a control unit, and an impedance matching unit. The plurality of power reception units are arranged on substantially the same plane, and each power reception unit can receive power in a non-contact manner from the power transmission unit of the power transmission device. The control unit executes scan control for sequentially receiving power from the power transmission unit by switching a plurality of power reception units, and determines a power reception unit to be used for power reception from the power transmission unit based on a power reception status from the power transmission unit when the scan control is executed. . The impedance matching unit adjusts the impedance based on the distance in the normal direction of the plane between the power receiving unit used for receiving power from the power transmitting unit and the power transmitting unit. Here, the control unit executes the scan control by setting the impedance matching unit in a state to be adjusted when the distance is equal to or less than a predetermined value. The predetermined value is a characteristic that the power transmission characteristic with respect to the positional deviation amount in the direction along the plane between the power receiving unit and the power transmitting unit used for receiving power from the power transmitting unit decreases in power transmission efficiency as the positional deviation amount increases. It is the said distance when showing.

  Preferably, the control unit sets the impedance matching device to a state to be adjusted when the distance is a predetermined minimum value, and executes scan control.

  Preferably, the power receiving device further includes a switch. The switch electrically connects any of the plurality of power receiving units to the electric load and electrically disconnects the remaining power receiving unit from the electric load. The control unit sequentially switches the power receiving unit that is electrically connected to the electric load by controlling the switch when the scan control is executed.

  According to the invention, the vehicle includes any one of the power receiving devices described above, a power storage device that stores the power received by the power receiving device, and an electric motor that generates a driving force by the power stored in the power storage device. Prepare.

  According to the invention, the power transmission system is a power transmission system that transmits power from the power transmission device to the power reception device, and includes a power transmission unit, a plurality of power reception units, a control unit, and an impedance matching unit. . The power transmission unit outputs the power received from the power source to the power receiving device in a contactless manner. The plurality of power reception units are arranged on substantially the same plane, and each power reception unit can receive power from the power transmission unit in a non-contact manner. The control unit executes scan control for sequentially receiving power from the power transmission unit by switching a plurality of power reception units, and determines a power reception unit to be used for power reception from the power transmission unit based on a power reception status from the power transmission unit when the scan control is executed. . The impedance matching unit is provided between the power source and the power transmission unit, and the impedance is adjusted based on the distance in the normal direction of the plane between the power transmission unit and the power reception unit used for receiving power from the power transmission unit. . Here, the control unit executes the scan control by setting the impedance matching unit in a state to be adjusted when the distance is equal to or less than a predetermined value. The predetermined value is such that the power transmission characteristic with respect to the positional deviation amount in the direction along the plane of the power transmission unit and the power receiving unit used for receiving power from the power transmission unit is such that the power transmission efficiency decreases as the positional deviation amount increases. It is the distance when showing.

  Preferably, the control unit sets the impedance matching device to a state to be adjusted when the distance is a predetermined minimum value, and executes scan control.

  In the present invention, by setting the impedance matching unit as described above and executing the scan control, the power transmission characteristic with respect to the positional shift amount between the power transmitting unit and the power receiving unit at the time of executing the scan control is Shows a single peak characteristic (one peak characteristic) in which the power transmission efficiency decreases with an increase in. Thereby, when the power transmission device includes a plurality of power transmission units, the power transmission unit closest to the power reception unit can be selected by the scan control, and when the power reception device includes a plurality of power reception units, the power transmission unit It is possible to select the power receiving unit closest to the. Therefore, according to the present invention, highly efficient power transmission can be realized.

1 is an overall configuration diagram of a power transmission system according to Embodiment 1 of the present invention. It is the figure which showed the example of arrangement | positioning of the power receiving part of a vehicle. It is the figure which showed the example of arrangement | positioning of the power transmission part of a power transmission apparatus. It is the figure which showed the structure of each power transmission part and a power receiving part. It is the figure which showed the other structural example of each power transmission part and a power receiving part. It is the figure which showed the structure of the matching device of a power transmission apparatus. 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 electric 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 or a magnetic current source, and the intensity | strength of an electromagnetic field. It is the figure which showed the influence which the relative positional relationship of a power transmission part and a power receiving part has on power transmission efficiency. It is a flowchart for demonstrating the selection process of a power transmission part. FIG. 3 is an overall configuration diagram of a power transmission system according to a second embodiment. It is the figure which showed the example of arrangement | positioning of the power receiving part of a vehicle. It is the figure which showed the example of arrangement | positioning of the power transmission part of a power transmission apparatus. It is a flowchart for demonstrating the selection process of a receiving part. It is a flowchart for demonstrating the selection process of the power receiving part in a modification.

  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.

[Embodiment 1]
(Configuration of power transmission system)
1 is an overall configuration diagram of a power transmission system according to Embodiment 1 of the present invention. Referring to FIG. 1, the power transmission system includes a vehicle 100 and a power transmission device 200. The power transmission device 200 includes a power supply unit 210, an impedance matching unit (hereinafter, also simply referred to as “matching unit”) 215, a plurality of power transmission units 220-1 to 220-5, a switch 225, and a communication unit 230. And a power transmission ECU (Electronic Control Unit) 240. Hereinafter, the plurality of power transmission units 220-1 to 220-5 may be collectively referred to as “power transmission unit 220”.

  The power supply unit 210 is controlled by a control signal PW from the power transmission ECU 240, and converts power received from a system power supply (not shown) into high-frequency power. The power supply unit 210 supplies the converted high frequency power to the power transmission unit 220 via the matching unit 215 and the switch 225.

  Matching device 215 is provided between power supply unit 210 and switching device 225. The matching unit 215 matches the input impedance of the power transmission unit 220 and the output impedance of the power supply unit 210, and is typically configured by a circuit including at least one of a variable reactor and a capacitor. The impedance of matching unit 215 is adjusted by control signal SE2 from power transmission ECU 240. The power supply unit 210 may include a function of the matching unit 215.

  Each of the power transmission units 220-1 to 220-5 is connected to the switch 225. The switch 225 electrically connects, among the power transmission units 220-1 to 220-5, the power transmission unit indicated by the control signal SW2 from the power transmission ECU 240 to the matching unit 215, and electrically disconnects the remaining power transmission units. Release. Each of the power transmission units 220-1 to 220-5 is electrically connected to the matching unit 215 by the switch 225, so that the high-frequency power supplied from the power supply unit 210 is contactless to the power reception unit 110 of the vehicle 100. Forward. In the first embodiment, five power transmission units 220-1 to 220-5 are illustrated, but the number of power transmission units is not limited to this. Note that specific configurations of the matching unit 215 and the power transmission unit 220 will be described later.

  Communication unit 230 is a communication interface for power transmission device 200 to perform wireless communication with vehicle 100, and exchanges various information with communication unit 155 of vehicle 100. The communication unit 230 receives vehicle information transmitted from the communication unit 155 of the vehicle 100, signals for instructing start and stop of power transmission, and the like, and outputs the received information, signals, and the like to the power transmission ECU 240. Communication unit 230 transmits information such as a power transmission voltage and a power transmission current received from power transmission ECU 240 to vehicle 100.

  The power transmission ECU 240 includes a CPU (Central Processing Unit), a storage device, an input / output buffer, and the like (none of which are shown), and inputs signals from sensors and outputs control signals to devices. Each device in the apparatus 200 is controlled. As main control of the power transmission ECU 240, the power transmission ECU 240 controls the power supply unit 210, sets and adjusts the matching unit 215, and switches the power transmission units 220-1 to 220-5 electrically connected to the power supply unit 210 by the switch 225. Scan control for switching sequentially, selection of a power transmission unit based on scan control, and the like are executed. Note that the control executed by the power transmission ECU 240 is not limited to processing by software, and can be processed by dedicated hardware (electronic circuit).

  On the other hand, vehicle 100 includes a power receiving unit 110, a rectifier 120, a matching unit 125, and a power storage device 130. Vehicle 100 also includes a power control unit (hereinafter also referred to as “PCU (Power Control Unit)”) 135, motor generator 140, power transmission gear 145, drive wheel 150, communication unit 155, and vehicle ECU 160. Further included.

  In the first embodiment, vehicle 100 is typically described as an electric vehicle (Electric Vehicle). However, vehicle 100 may be any vehicle that can travel using electric power stored in power storage device 130. Is not limited to this. Other examples of the vehicle 100 include a hybrid vehicle equipped with an engine, a fuel cell vehicle equipped with a fuel cell, and the like.

  The power reception unit 110 receives power from the power transmission unit 220 of the power transmission device 200 in a contactless manner, and outputs the received power to the rectifier 120. Note that the specific configuration of the power receiving unit 110 will be described in detail later together with the configuration of the power transmission unit 220 of the power transmission device 200.

  The rectifier 120 rectifies the power received by the power receiving unit 110 and outputs the rectified DC power to the matching unit 125. For example, the rectifier 120 may have a static circuit configuration including a diode bridge and a smoothing capacitor (both not shown). As the rectifier 120, a so-called switching regulator that performs rectification using switching control can also be used. When the rectifier 120 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 electromagnetic field.

  Matching device 125 is provided between rectifier 120 and power storage device 130. The matching unit 125 matches the output impedance of the power receiving unit 110 and the input impedance of the power storage device 130. For example, the matching unit 125 includes a DC / DC converter that can adjust the input voltage level of the matching unit 125. That is, when the output voltage of matching unit 125 is constrained by the voltage of power storage device 130, the input voltage of the DC / DC converter is √ (P × R) (P indicates received power and R indicates received impedance). By adjusting to, the output impedance of the power receiving unit 110 and the input impedance of the power storage device 130 can be matched. Although not particularly illustrated, a matching device having the same configuration as that of the matching device 215 of the power transmission device 200 may be provided between the power receiving unit 110 and the rectifier 120 instead of the matching device 125.

  The power storage device 130 is a power storage element configured to be rechargeable. The power storage device 130 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 130 stores the power received by the power receiving unit 110. The power storage device 130 is also electrically connected to the PCU 135 and supplies power to the PCU 135 for generating vehicle driving force. Furthermore, power storage device 130 receives power generated by motor generator 140 from PCU 135 and stores the power.

  In addition, power storage device 130 is provided with a voltage sensor and a current sensor (not shown) for detecting voltage VB and current IB of power storage device 130, respectively. Detection values of these sensors are output to the vehicle ECU 160. Based on the detected values of voltage VB and current IB, vehicle ECU 160 is also referred to as the state of charge of power storage device 130 (“SOC (State Of Charge)”), and is expressed as 0 to 100% with the fully charged state being 100%. Estimated).

  The PCU 135 includes a converter and an inverter (both not shown). The converter is controlled by a control signal PWC from vehicle ECU 160 and performs voltage conversion between power storage device 130 and the inverter. The inverter is controlled by a control signal PWI from vehicle ECU 160 and drives motor generator 140 using electric power that has been voltage-converted by a converter.

  Motor generator 140 is an AC rotating electric machine, and is constituted by a permanent magnet type synchronous motor including a rotor in which permanent magnets are embedded, for example. The output torque of motor generator 140 is transmitted to drive wheel 150 via power transmission gear 145. The vehicle 100 travels using this torque. The motor generator 140 can generate power by the rotational force of the drive wheels 150 during regenerative braking of the vehicle 100. The electric power generated by motor generator 140 is voltage-converted by PCU 135 and stored in power storage device 130.

  In a hybrid vehicle equipped with an engine (not shown) in addition to motor generator 140, necessary vehicle driving force is generated by operating engine and motor generator 140 in a coordinated manner. In this case, the power storage device 130 can be charged by generating electric power using the power of the engine.

  Communication unit 155 is a communication interface for vehicle 100 to perform wireless communication with power transmission device 200, and exchanges various information with communication unit 230 of power transmission device 200. Information output from the communication unit 155 to the power transmission device 200 includes vehicle information from the vehicle ECU 160, signals for instructing start and stop of power transmission, and the like.

  The vehicle ECU 160 includes a CPU, a storage device, an input / output buffer, and the like (all not shown), inputs signals from the sensors and the like and outputs control signals to the devices, and controls each device in the vehicle 100. Take control. Note that these controls are not limited to processing by software, and can be processed by dedicated hardware (electronic circuit).

  FIG. 2 is a diagram illustrating an arrangement example of the power receiving unit 110 of the vehicle 100. FIG. 3 is a diagram illustrating an arrangement example of the power transmission units 220-1 to 220-5 of the power transmission device 200. Referring to FIG. 2, power receiving unit 110 is disposed, for example, at the lower part of the vehicle body near the rear of the vehicle body. Referring to FIG. 3, power transmission units 220-1 to 220-5 are arranged on the ground in parking frame 250 where a vehicle that receives power supply from power transmission device 200 is parked. The power transmission units 220-1 to 220-5 can accommodate various arrangements of the power reception unit in the vehicle that receives power from the power transmission device 200 and both forward parking and reverse parking to the parking frame 250. For example, they are arranged at substantially equal intervals in the longitudinal direction of the vehicle.

  FIG. 4 is a diagram illustrating the configuration of each of the power transmission units 220-1 to 220-5 and the power reception unit 110. In addition, the structure of each power transmission part 220-1 to 220-5 is the same, and here, the power transmission part 220-1 is demonstrated typically. Referring to FIG. 4, power transmission unit 220-1 includes coil 221 (hereinafter also referred to as “resonance coil” and may be appropriately referred to as “resonance coil”), capacitor 222, and coil 223 (hereinafter referred to as “electromagnetic”). Also referred to as an induction coil).

  The electromagnetic induction coil 223 can be magnetically coupled to the resonance coil 221 by electromagnetic induction. The electromagnetic induction coil 223 transmits the high frequency power supplied from the power supply unit 210 (FIG. 1) to the resonance coil 221 by electromagnetic induction. The resonance coil 221 transfers the electric power transmitted from the electromagnetic induction coil 223 to the power receiving unit 110 of the vehicle 100 in a non-contact manner.

  The power receiving unit 110 includes a coil 111 (hereinafter also referred to as “resonance coil” and may be appropriately referred to as “resonance coil”), a capacitor 112, and a coil 113 (hereinafter also referred to as “electromagnetic induction coil”). Including.

  The resonance coil 111 receives electric power from the resonance coil 221 of the power transmission unit 220-1 in a non-contact manner. The electromagnetic induction coil 113 can be magnetically coupled to the resonance coil 111 by electromagnetic induction. The electromagnetic induction coil 113 takes out the electric power received by the resonance coil 111 by electromagnetic induction and outputs it to the rectifier 120.

  In FIG. 4, the power receiving unit 110 and the power transmitting unit 220-1 (220-2 to 220-5) have the electromagnetic induction coils 113 and 223, respectively. However, like the configuration illustrated in FIG. 5. The power reception unit 110 and the power transmission unit 220-1 (220-2 to 220-5) may be configured not to include an electromagnetic induction coil. In this case, in power transmission unit 220-1 (220-2 to 220-5), resonance coil 221 is connected to switch 225, and in power reception unit 110, resonance coil 111 is connected to rectifier 120.

  In the power transmission unit 220-1 (220-2 to 220-5), the capacitor 224 is connected in series to the resonance coil 221 to form an LC resonance circuit with the resonance coil 221, but the capacitor 224 is the resonance coil 221. May be connected in parallel. Also in the power receiving unit 110, the capacitor 114 is connected in series to the resonance coil 111 to form the LC resonance circuit with the resonance coil 111. However, the capacitor 114 may be connected to the resonance coil 111 in parallel.

  FIG. 6 is a diagram showing a configuration of matching unit 215 of power transmission device 200. Referring to FIG. 6, matching unit 215 includes a capacitor 216 and a reactor 217, and at least one of capacitor 216 and reactor 217 is configured to be variable. Matching device 215 adjusts the impedance to a desired impedance by changing the capacitance of capacitor 216 and / or the reactance of reactor 217 based on control signal SE2 from power transmission ECU 240 (FIG. 1). The above variable element is not limited to one whose capacitance and reactance continuously change, but the capacitance and the reactor connected in series and / or in parallel are switched by a changeover switch such as a relay in stages. Etc. may be changed.

(Principle of power transmission)
Next, the principle of non-contact power transmission from the power transmission device 200 to the vehicle 100 will be described.

  FIG. 7 is an equivalent circuit diagram when power is transmitted from power transmission device 200 to vehicle 100. Referring to FIG. 7, in power transmission device 200, electromagnetic induction coil 223 of power transmission unit 220 is provided substantially coaxially with resonance coil 221, for example, at a predetermined interval from 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 unit 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 supply from the power supply unit 210 to the resonance coil 221. As shown in FIG. 5, the electromagnetic induction coil 223 is not provided in the resonance coil 221. The power supply unit 210 may be directly connected. 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.

  On the other hand, in vehicle 100, resonance coil 111 of power reception unit 110 forms an LC resonance circuit together with capacitor 112. 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 118. The electrical load 118 is an electrical device that uses the power received by the power receiving unit 110, and specifically represents the electrical device after the rectifier 120 (FIG. 1).

  The electromagnetic induction coil 113 is provided for facilitating the extraction of electric power from the resonance coil 111. As shown in FIG. 5, the electromagnetic induction coil 113 is not provided and the resonance coil 111 is electrically loaded. You may connect directly to 118. 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 unit 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 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, if the difference between the natural frequencies is larger than ± 10%, there is a possibility that the power transmission efficiency becomes 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.

  A simulation result obtained by analyzing the relationship between the natural frequency difference and the power transmission efficiency will be described with reference to FIGS. 8 and 9. FIG. 8 is a diagram illustrating a simulation model of the power transmission system. FIG. 9 is a diagram illustrating the relationship between the deviation of the natural frequency of the power transmission unit and the power reception unit and the power transmission efficiency.

  With reference to FIG. 8, 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 represented by the following equation (1), and the natural frequency f2 of the third coil 96 is represented 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. 9, 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. 9, when the deviation (%) in 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 to FIG. 7 again, power transmission unit 220 and power reception unit 110 exchange power in a non-contact manner through at least one of a magnetic field and an electric field formed between power transmission unit 220 and power reception unit 110. A magnetic field and / or electric field formed between the power transmission unit 220 and the power reception unit 110 vibrates at a specific frequency. Then, 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.

  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. 10 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. 10, 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.

  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, coils (for example, helical coils) are employed for the power transmission unit 220 and the power reception unit 110. However, antennas such as meander lines may be employed instead of the coils. When an antenna such as a meander line is employed, a current with a specific frequency flows through the power transmission unit 220, so that an electric field with 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. 11 is a diagram showing the relationship between the distance from the current source or the magnetic current source and the strength of the electromagnetic field. Referring to FIG. 7, 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.

  As described above, in this power transmission system, power is transmitted in a non-contact manner between the power transmission unit 220 and 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. . Such an electromagnetic field formed between the power transmission unit 220 and the power reception unit 110 may be referred to as a near-field resonance (resonance) coupling field, for example. The coupling coefficient (κ) between the power transmission unit 220 and the power reception unit 110 is, for example, about 0.3 or less, and preferably 0.1 or less. As a matter of course, a coupling coefficient (κ) in the range of about 0.1 to 0.3 can also be adopted. The coupling coefficient (κ) is not limited to such a value, and may take various values that improve power transmission.

  Note that the coupling between the power transmission unit 220 and the power reception unit 110 in the power transmission is, for example, “magnetic resonance coupling”, “magnetic field (magnetic field) resonance coupling”, “magnetic field resonance (resonance) coupling”, “proximity” The field resonance (resonance) coupling, the electromagnetic field (electromagnetic field) resonance coupling, the electric field (electric field) resonance coupling, and the like. 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.

(Scan control of power transmission units 220-1 to 220-5)
As described above, in the first embodiment, various arrangements of the power reception unit in the vehicle that receives power from the power transmission device 200, or both the case of forward parking and the case of reverse parking in the parking frame 250 (FIG. 3). A plurality of power transmission units 220-1 to 220-5 are provided in the power transmission device 200 so as to be compatible.

  Then, after parking in the parking frame 250 is completed, test power transmission (power transmission smaller than the power transmitted for charging the power storage device 130) is started from the power transmission device 200 to the vehicle 100 and is electrically connected to the power supply unit 210. Scan control for sequentially switching the power transmission units 220-1 to 220-5 by the switch 225 is executed. When this scan control is executed, the power transmission unit closest to the power reception unit 110 is selected based on the power transmission efficiency between the power transmission units 220-1 to 220-5 and the power reception unit 110. Instead of the power transmission efficiency, the power transmission status such as the received power, the received voltage, the received current, and the reflected power in the power transmission device 200 of the power receiving unit 110 may be used. Then, power is supplied from power transmission device 200 to vehicle 100 using the selected power transmission unit.

  In the first embodiment, matching device 215 is provided in power transmission device 200 in order to improve the power transmission efficiency between the selected power transmission unit and power reception unit 110. The power transmission efficiency varies depending on the relative positional relationship between the power transmission unit and the power reception unit. The relative positional relationship between the power transmission unit and the power reception unit is defined by the amount of positional deviation, which is the horizontal distance between the power transmission unit and the power reception unit, and the vertical distance between the power transmission unit and the power reception unit. Here, the horizontal direction is a direction parallel to the ground on which the plurality of power transmission units 220-1 to 220-5 are arranged, and the vertical distance between the power transmission unit and the power reception unit corresponds to the vehicle height. The vehicle height varies depending on the passenger boarding / exiting and the loading situation of the luggage. When the vehicle height changes, the distance between the power transmission unit and the power reception unit changes. Then, the impedance between the power transmission unit and the power reception unit changes, thereby changing the power transmission efficiency. Therefore, in the first embodiment, the impedance of the matching unit 215 is adjusted based on the vehicle height, and the power transmission efficiency is improved.

  However, depending on the setting of the matching unit 215 when executing the scan control, there is a possibility that a power transmission unit farther than the power transmission unit closest to the power reception unit 110 may be selected.

  FIG. 12 is a diagram illustrating the influence of the relative positional relationship between a power transmission unit and a power reception unit used for power transmission on power transmission efficiency. Referring to FIG. 12, the horizontal axis indicates the amount of horizontal displacement between the power transmission unit and the power reception unit (hereinafter, “position displacement amount” refers to the amount of horizontal displacement between the power transmission unit and the power reception unit. The vertical axis represents the power transmission efficiency between the power transmission unit and the power reception unit. As for the amount of positional deviation, for example, when the case where the power receiving unit is deviated forward of the vehicle body with respect to the power transmitting unit used for power transmission is positive, the power receiving unit is deviated rearward of the vehicle body with respect to the power transmitting unit. A negative value is indicated.

  A curve S1 shows a change in power transmission efficiency with respect to a positional deviation amount when the matching unit 215 is ideally adjusted. In this case, the power transmission efficiency is maximized when the positional deviation is zero, and the peak exhibits a single peak characteristic in which the power transmission efficiency gradually decreases as the positional deviation increases.

  A curve S2 shows a change in power transmission efficiency with respect to a positional deviation amount when the matching device 215 is set to a state to be adjusted when the vehicle height is a predetermined minimum value. In this case, the actual vehicle height is higher than the assumed vehicle height (that is, the distance between the power transmission unit and the power reception unit is long), and the power transmission efficiency is generally improved with a single peak characteristic. Transmission characteristics that are smaller than the curve S1 are shown.

  A curve S3 indicates a change in power transmission efficiency with respect to a positional deviation amount when the matching unit 215 is set in a state to be adjusted when the vehicle height is high. In this case, the actual vehicle height is lower than the assumed vehicle height (that is, the distance between the power transmission unit and the power reception unit is short), and the transmission efficiency is lower in the region where the positional deviation is small than in the surrounding region. The peak produced by the reduction shows two bimodal characteristics. It is known that such a bimodal characteristic appears when the coupling coefficient between the power transmission unit and the power reception unit increases.

  When such a bimodal characteristic appears in the power transmission efficiency with respect to the positional deviation amount, there is a possibility that the power transmission unit closest to the power receiving unit 110 cannot be selected based on the power transmission efficiency. Therefore, in the first embodiment, the matching unit is adjusted to a state that should be adjusted when the vehicle height is equal to or less than a predetermined value so that the characteristic of the power transmission efficiency with respect to the positional deviation amount becomes a single peak characteristic when the scan control is executed. 215 is set. Preferably, matching device 215 is set to a state to be adjusted when the vehicle height is a predetermined minimum value. As a result, when the scan control is executed, the power transmission efficiency characteristic with respect to the positional shift amount becomes a unimodal characteristic, and the power transmission unit closest to the power receiving unit 110 can be reliably selected based on the power transmission efficiency.

  FIG. 13 is a flowchart for explaining the power transmission unit selection process. Each step in the flowchart is realized mainly by a program stored in advance in power transmission ECU 240 being called from the main routine and executed in response to a predetermined period or a predetermined condition being satisfied. . Alternatively, processing can be realized by constructing dedicated hardware (electronic circuit) for all or some of the steps.

  Referring to FIG. 1 together with FIG. 13, power transmission ECU 240 determines whether or not the parking operation of parking frame 250 (FIG. 3) of vehicle 100 has been started (step S10). The power transmission ECU 240 can recognize the start of the parking operation of the vehicle 100 by communicating with the vehicle 100 through the communication unit 230. When the parking operation is not started (NO in step S10), the process proceeds to step S60 without executing a series of subsequent processes. When the parking operation is started (YES in step S10), power transmission ECU 240 determines whether or not the parking operation is completed (step S15).

  When the parking operation is completed (YES in step S15), the power transmission ECU 240 sets the circuit of the matching unit 215 of the power transmission device 200 to a value when the gap (corresponding to the vehicle height) between the power transmission unit 220 and the power reception unit 110 is the minimum. A constant is set (step S20). That is, the relationship between the setting state of the matching unit 215 and the vehicle height (gap between the power transmission unit and the power reception unit) is predetermined, and should be adjusted when the vehicle height is a predetermined minimum value. The matching unit 215 is set to the state. Then, the power transmission ECU 240 starts scan control of the power transmission units 220-1 to 220-5 (step S25).

  In this scan control, test power transmission from the power transmission device 200 to the vehicle 100 is performed while the power transmission units 220-1 to 220-5 electrically connected to the power supply unit 210 are sequentially switched by the switch 225. Then, at the time of executing the scan control, the power transmission efficiency is calculated based on the received power of the power receiving unit 110 for each of the power transmitting units 220-1 to 220-5. When the test power transmission by each of the power transmission units 220-1 to 220-5 is completed, the power transmission ECU 240 ends the scan control (step S30). Then, power transmission ECU 240 determines that the power transmission unit having the highest power transmission efficiency among power transmission units 220-1 to 220-5 is used for power transmission to vehicle 100 (step S35).

  When the power transmission unit used for power transmission to vehicle 100 is determined, power transmission ECU 240 adjusts matching unit 215 of power transmission device 200 again for the purpose of improving power transmission efficiency (step S40). Specifically, for example, a vehicle height sensor may be provided, and the matching unit 215 may be adjusted to a setting prepared in advance in association with the detected value, or the power transmission efficiency may be adjusted at a plurality of predetermined adjustment points. The matching unit 215 may be set based on the calculation result.

  When adjustment of matching unit 215 is completed, power transmission ECU 240 stops test power transmission (step S45). Thereafter, power transmission ECU 240 starts power transmission processing for charging power storage device 130 of vehicle 100 (step S50).

  As described above, in the first embodiment, the matching unit 215 is adjusted to a state that should be adjusted when the vehicle height is equal to or less than a predetermined value so that the characteristic of the power transmission efficiency with respect to the positional deviation amount is a single peak characteristic. Set and execute scan control. Preferably, the matching unit 215 is set to a state to be adjusted when the vehicle height is a predetermined minimum value, and the scan control is executed. As a result, the power transmission unit closest to the power reception unit 110 can be selected. Therefore, according to this Embodiment 1, it becomes possible to implement | achieve highly efficient electric power transmission.

[Embodiment 2]
In Embodiment 1, power transmission device 200 has a plurality of power transmission units. However, in Embodiment 2, a configuration in which a vehicle has a plurality of power receptions is shown.

  FIG. 14 is an overall configuration diagram of the power transmission system according to the second embodiment. Referring to FIG. 14, the power transmission system includes a vehicle 100A and a power transmission device 200A. Power transmission device 200A does not include switch 225 in the configuration of power transmission device 200 in Embodiment 1 shown in FIG. 1, and includes one power transmission unit 220A instead of a plurality of power transmission units 220-1 to 220-5. . In addition, vehicle 100A includes a plurality of power receiving units 110-1 to 110-5 and vehicle ECU 160A in place of power receiving unit 110 and vehicle ECU 160 in the configuration of vehicle 100 in the first embodiment shown in FIG. Further included is a vessel 115. Hereinafter, the plurality of power receiving units 110-1 to 110-5 may be collectively referred to as “power receiving unit 110A”.

  In power transmission device 200 </ b> A, power transmission unit 220 </ b> A is electrically connected to matching unit 215 and transfers high-frequency power supplied from power supply unit 210 via matching unit 215 to power reception unit 110 </ b> A of vehicle 100 in a contactless manner.

  In vehicle 100A, each of power reception units 110-1 to 110-5 is connected to switch 115. The switch 115 electrically connects the power receiving unit indicated by the control signal SW1 from the vehicle ECU 160A among the power receiving units 110-1 to 110-5 to the rectifier 120, and electrically disconnects the remaining power receiving units. . When each of the power receiving units 110-1 to 110-5 is electrically connected to the rectifier 120 by the switch 115, the power receiving unit 110-1 to 110-5 receives the power transmitted from the power transmission unit 220 </ b> A of the power transmission device 200 </ b> A in a contactless manner. Output to. In the second embodiment, five power receiving units 110-1 to 110-5 are illustrated, but the number of power receiving units is not limited to this.

  Other configurations of power transmission device 200A and vehicle 100A are the same as those of power transmission device 200 and vehicle 100 shown in the first embodiment, respectively.

  FIG. 15 is a diagram illustrating an arrangement example of the power receiving units 110-1 to 110-5 of the vehicle 100A. FIG. 16 is a diagram illustrating an arrangement example of the power transmission unit 220A of the power transmission device 200A. Referring to FIG. 15, power reception units 110-1 to 110-5 can cope with various arrangements of power transmission unit 220 </ b> A in power transmission device 200 </ b> A and both forward parking and reverse parking in parking frame 250 of vehicle 100 </ b> A. Thus, for example, they are arranged at substantially equal intervals in the longitudinal direction of the vehicle body of the vehicle 100A. On the other hand, referring to FIG. 16, power transmission unit 220 </ b> A is appropriately arranged in parking frame 250 where a vehicle that receives power from power transmission device 200 </ b> A is parked.

  Also in the second embodiment, after completion of parking in the parking frame, test power transmission is started from the power transmission device 200A to the vehicle 100A, and the power receiving units 110-1 to 110-5 that are electrically connected to the rectifier 120 in the vehicle 100A are installed. Scan control for sequentially switching is performed by the switch 115. When this scan control is executed, the power receiving unit closest to the power transmitting unit 220A is selected based on the power transmission efficiency between the power transmitting unit 220A and each of the power receiving units 110-1 to 110-5, and the selected power receiving unit is used. Then, power is received from the power transmission unit 220A.

  In the second embodiment as well, the vehicle 100A is set to a state that should be adjusted when the vehicle height is equal to or less than a predetermined value so that the characteristic of the power transmission efficiency with respect to the positional deviation amount becomes a single peak characteristic when the scan control is executed. The matching device 125 is set. Preferably, matching unit 125 is set to be adjusted when the vehicle height is a predetermined minimum value. Thus, when the scan control is executed, the power transmission efficiency characteristic with respect to the positional deviation amount becomes a single peak characteristic, and the power receiving unit closest to the power transmission unit 220A can be reliably selected based on the power transmission efficiency.

  FIG. 17 is a flowchart for explaining the power receiving unit selection process. Each step in the flowchart is realized mainly by a program stored in advance in vehicle ECU 160A being called from the main routine and executed in response to a predetermined cycle or a predetermined condition being satisfied. . Alternatively, processing can be realized by constructing dedicated hardware (electronic circuit) for all or some of the steps.

  Referring to FIG. 14 together with FIG. 17, vehicle ECU 160A determines whether or not the parking operation to parking frame 250 (FIG. 16) in which power transmission unit 220A of power transmission device 200A is provided has been started (step S110). When the parking operation is not started (NO in step S110), the process proceeds to step S160 without executing a series of subsequent processes. If it is determined that the parking operation has started (YES in step S110), vehicle ECU 160A determines whether or not the parking operation has been completed (step S115).

  When the parking operation is completed (YES in step S115), vehicle ECU 160A sets matching unit 125 of vehicle 100A to the value when the gap (corresponding to the vehicle height) between power transmission unit 220A and power reception unit 110A is the minimum. (Step S120). That is, the relationship between the setting state of the matching unit 125 and the vehicle height (gap between the power transmission unit and the power reception unit) is predetermined, and should be adjusted when the vehicle height is a predetermined minimum value. The matching unit 125 is set to the state. Thereafter, vehicle ECU 160A transmits a test power transmission start command to power transmission device 200A (step S125). When test power transmission is started, vehicle ECU 160A starts scan control of power reception units 110-1 to 110-5 (step S130).

  In this scan control, the power receiving units 110-1 to 110-5 that are electrically connected to the rectifier 120 are sequentially switched by the switch 115, and the test power is received from the power transmitting device 200A. Then, at the time of executing the scan control, the power transmission efficiency is calculated based on the received power for each of the power receiving units 110-1 to 110-5. When the power reception by each of power reception units 110-1 to 110-5 is completed, vehicle ECU 160A ends the scan control (step S135). Then, vehicle ECU 160A determines that the power receiving unit having the highest power transmission efficiency among power receiving units 110-1 to 110-5 is used for power reception from power transmission device 200A (step S140).

  When the power receiving unit used for receiving power from power transmission device 200A is determined, vehicle ECU 160A transmits a test power transmission stop command to power transmission device 200A (step S145). Then, vehicle ECU 160A adjusts matching unit 125 of vehicle 100A based on the setting of charging power to power storage device 130 for the purpose of improving power transmission efficiency (step S150). The setting of the charging power to power storage device 130 is determined based on, for example, the SOC of power storage device 130, and is set to low power when SOC is high, and is set to high power when SOC is low. Alternatively, the charging power may be set based on the rated output on the power transmission device 200A side. The vehicle ECU 160A controls the matching unit 125 so that the input voltage of the matching unit 125 (DC / DC converter) becomes √ (P × R) (P indicates charging power and R indicates power receiving impedance). To do.

  When adjustment of matching unit 125 is completed, vehicle ECU 160A starts a power receiving process for charging power storage device 130 (step S155).

  As described above, in the second embodiment, vehicle 100A includes a plurality of power receiving units 110-1 to 110-5. Then, the matching unit 125 of the vehicle 100A is set to a state to be adjusted when the vehicle height is equal to or less than a predetermined value so that the power transmission efficiency characteristic with respect to the positional deviation amount becomes a single peak characteristic, and the scan control is executed. The Preferably, the matching unit 125 is set to a state to be adjusted when the vehicle height is a predetermined minimum value, and the scan control is executed. As a result, the power receiving unit closest to the power transmitting unit 220A can be selected. Therefore, also according to the second embodiment, it is possible to realize highly efficient power transmission.

[Modification]
In the second embodiment, the matching device 125 of the vehicle 100A is set so that the characteristic of the power transmission efficiency with respect to the positional deviation amount becomes a single-peak characteristic when the scan control is executed. Instead of 125, matching device 215 of power transmission device 200A may be set in the same manner as in the first embodiment.

  FIG. 18 is a flowchart for explaining a power receiving unit selection process in this modification. It should be noted that each step in this flowchart is also executed in response to the fact that a program stored in advance in vehicle ECU 160A and power transmission ECU 240 is called from the main routine and a predetermined cycle or a predetermined condition is satisfied. It is realized by. Alternatively, processing can be realized by constructing dedicated hardware (electronic circuit) for all or some of the steps.

  With reference to FIG. 14 together with FIG. 18, the processing of the power transmission device 200A will be described first. When the parking operation of vehicle 100A is completed (YES in step S210), power transmission device 200A matches power transmission device 200A to the state when the gap (corresponding to the vehicle height) between power transmission unit 220A and power reception unit 110A is minimum. The circuit constant of the device 215 is set (step S215).

  Next, power transmission device 200A starts test power transmission to vehicle 100A (step S220). Then, scan control of power reception units 110-1 to 110-5 is executed in vehicle 100A. When the scan control ends (YES in step S225), power transmission device 200A stops test power transmission to vehicle 100A (step S230). Thereafter, the power transmission device 200A adjusts the matching unit 215 again for the purpose of improving the power transmission efficiency (step S235). When the adjustment of matching unit 215 is completed, power transmission device 200A starts a power transmission process for charging power storage device 130 of vehicle 100A (step S240).

  On the other hand, in vehicle 100A, the parking operation to parking frame 250 (FIG. 16) provided with power transmission unit 220A of power transmission device 200A is started (YES in step S310), and when the parking operation is completed (YES in step S315), Vehicle 100A determines whether or not the test power transmission from power transmission device 200A has been received (step S320).

  When power reception from power transmission device 200A is determined (YES in step S320), vehicle 100A starts scan control of power reception units 110-1 to 110-5 (step S325). When the vehicle 100A ends the scan control (step S330), the vehicle 100A notifies the power transmission device 200A to that effect, and determines a power reception unit to be used for power reception from the power transmission device 200A based on the result of the scan control (step S330). S335).

  Thereafter, vehicle 100A adjusts matching unit 125 based on the setting of charging power to power storage device 130 (step S340). When adjustment of matching unit 125 is completed, vehicle 100A is configured to charge power storage device 130. The power receiving process is started (step S345).

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  100, 100A vehicle, 110 power receiving unit, 111, 113, 221, 223 coil, 112, 114, 222, 224 capacitor, 115, 225 switcher, 118 electrical load, 120 rectifier, 125, 215 matching unit, 130 power storage device, 135 PCU, 140 motor generator, 145 power transmission gear, 150 drive wheel, 155, 230 communication unit, 160, 160A vehicle ECU, 200, 200A power transmission device, 210 power source unit, 216 capacitor, 217 reactor, 220 power transmission unit, 240 power transmission ECU, 250 parking frame.

Claims (13)

A power transmission device that supplies power to a power reception device,
A plurality of power transmission units arranged in substantially the same plane, each capable of outputting power received from a power source in a non-contact manner to the power reception unit of the power receiving device;
Execute scan control for sequentially switching the plurality of power transmission units to transmit power to the power reception unit, and determine a power transmission unit to be used for power transmission to the power reception unit based on a power transmission state to the power reception unit at the time of execution of the scan control A control unit,
An impedance matching unit whose impedance is adjusted based on a distance in a normal direction of the plane between the power transmission unit and the power reception unit used for power transmission to the power reception unit;
The control unit performs the scan control by setting the impedance matching unit in a state to be adjusted when the distance is equal to or less than a predetermined value,
The predetermined value indicates that the power transmission characteristic with respect to the positional deviation amount in the direction along the plane between the power transmitting unit and the power receiving unit used for power transmission to the power receiving unit decreases, and the power transmission efficiency decreases as the positional deviation amount increases. The power transmission device, which is the distance when exhibiting the characteristics to be performed.   The power transmission device according to claim 1, wherein the control unit sets the impedance matching unit to a state to be adjusted when the distance is a predetermined minimum value, and executes the scan control.   The control unit adjusts the impedance of the impedance matching unit based on a power transmission efficiency during power transmission from the power transmission unit used for power transmission to the power reception unit after execution of the scan control. Item 2. The power transmission device according to Item 1. A switch is further provided that electrically connects any of the plurality of power transmission units to the power source and electrically disconnects the remaining power transmission unit from the power source,
The power transmission device according to claim 1, wherein the control unit sequentially switches power transmission units electrically connected to the power source by controlling the switch when the scan control is executed.   The difference between the natural frequency of the power transmission unit used for power transmission to the power reception 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 power transmission device described in 1.   The power transmission device according to claim 1, wherein a coupling coefficient between a power transmission unit used for power transmission to the power reception unit and the power reception unit is 0.3 or less. The power transmission unit used for power transmission to the power reception unit passes through at least one of a magnetic field formed between the power transmission unit and the power reception unit and an electric field formed between the power transmission unit and the power reception unit. , Transmit power to the power receiving unit,
The power transmission device according to claim 1, wherein the magnetic field and the electric field are formed between the power transmission unit and the power reception unit and vibrate at a specific frequency. A power receiving device that receives power from a power transmitting device,
A plurality of power receiving units arranged in substantially the same plane, each capable of receiving power in a non-contact manner from the power transmission unit of the power transmission device;
A scan control for receiving power from the power transmission unit by sequentially switching the plurality of power reception units is executed, and a power reception unit used for power reception from the power transmission unit is determined based on a power reception status from the power transmission unit at the time of execution of the scan control A control unit,
An impedance matching device whose impedance is adjusted based on a distance in a normal direction of the plane between the power receiving unit and the power transmitting unit used for receiving power from the power transmitting unit;
The control unit performs the scan control by setting the impedance matching unit in a state to be adjusted when the distance is equal to or less than a predetermined value,
The predetermined value indicates that the power transmission characteristic with respect to the positional deviation amount in the direction along the plane between the power receiving unit and the power transmitting unit used for receiving power from the power transmission unit decreases, and the power transmission efficiency decreases as the positional deviation amount increases. The power receiving device, which is the distance when exhibiting the characteristics to be performed.   The power receiving device according to claim 8, wherein the control unit sets the impedance matching device to a state to be adjusted when the distance is a predetermined minimum value, and executes the scan control. A switch that electrically connects any of the plurality of power reception units to an electrical load and electrically disconnects the remaining power reception unit from the electrical load;
The power reception device according to claim 8, wherein the control unit sequentially switches power reception units electrically connected to the electric load by controlling the switch when the scan control is executed. A power receiving device according to claim 8;
A power storage device for storing the power received by the power receiving device;
A vehicle comprising: an electric motor that generates a driving force for driving using electric power stored in the power storage device. A power transmission system for transmitting power from a power transmission device to a power reception device,
A power transmission unit that outputs power received from a power source to the power receiving device in a contactless manner;
A plurality of power receiving units arranged in substantially the same plane, each capable of receiving power from the power transmitting unit in a contactless manner;
A scan control for receiving power from the power transmission unit by sequentially switching the plurality of power reception units is executed, and a power reception unit used for power reception from the power transmission unit is determined based on a power reception status from the power transmission unit at the time of execution of the scan control A control unit,
Impedance provided between the power source and the power transmission unit, the impedance of which is adjusted based on the distance in the normal direction of the plane between the power transmission unit and the power reception unit used for power reception from the power transmission unit With a matching unit,
The control unit performs the scan control by setting the impedance matching unit in a state to be adjusted when the distance is equal to or less than a predetermined value,
The predetermined value indicates that the power transmission characteristic with respect to the positional deviation amount in the direction along the plane between the power transmission unit and the power receiving unit used for receiving power from the power transmission unit decreases, and the power transmission efficiency decreases as the positional deviation amount increases. The power transmission system, which is the distance when exhibiting the characteristics to be performed.   The power transmission system according to claim 12, wherein the control unit sets the impedance matching unit to a state to be adjusted when the distance is a predetermined minimum value, and executes the scan control.

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