Power transmission equipment, contactless power supply system, and power transmission method

Abstract

To provide a technique capable of suppressing or preventing such a defect that power supply from a power transmission device to a power reception device does not start when the power reception device changes from a non-opposite state to an opposite state with respect to the power transmission device, in the power transmission device.SOLUTION: A power transmission device 100 for supplying power in a non-contact manner to a movable power reception device 200 includes: a power transmission resonant circuit 110 having a power transmitting coil 112 and a power transmission resonant capacitor; a power transmission circuit 130 for supplying AC power to the power transmission resonant circuit; a power transmission request signal reception section 172 for receiving a power transmission request signal originating from the power reception device; and a switching section 174 for switching the value of a current flowing through the power transmitting coil, the switching section switching the value of current flowing through the power transmitting coil to the value of a current that can be supplied to the power reception device, by changing the input impedance of the power transmission resonant circuit upon reception of the power transmission request signal.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a power transmission device, a contactless power supply system, and a power transmission method.

Background Art

[0002] A contactless power supply system including a power transmission device and a power reception device that switches the input impedance of a power transmission-side resonant circuit using a variable capacitor is known (for example, Patent Document 1). In this contactless power supply system, the capacitance of the variable capacitor is set to change in accordance with the change in magnetic flux generated in the power transmission coil when the power reception coil changes from a non-opposing state to an opposing state with respect to the power transmission coil. Specifically, in a state where the power reception coil and the power transmission coil face each other, the capacitance of the variable capacitor is switched to a small value, whereby the input impedance is reduced to establish a power supply state in which a large current flows through the power transmission coil. In a state where the power reception coil and the power transmission coil do not face each other, the capacitance of the variable capacitor is switched to a large value, whereby the input impedance is increased to establish a non-power supply state in which a standby current flows through the power transmission coil.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problem to be Solved by the Invention

[0004] However, due to variations in the size and shape of the power reception coil, variations in the relative position of the power reception coil with respect to the power transmission coil, and the like, the change in magnetic flux generated in the power transmission coil may be small even when the power reception coil changes from the non-opposing state to the opposing state with respect to the power transmission coil. In this case, the power transmission coil and the power reception coil cannot resonate, and power supply from the power transmission device to the power reception device may not be started.

Means for Solving the Problem

[0005] This disclosure can be implemented in the following forms:

[0006] According to a first embodiment of the present disclosure, a power transmission device (100) is provided for non-contact power supply to a movable power receiving device (200). The power transmission device comprises a power transmission resonant circuit (110) having a power transmission coil (112) and a power transmission resonant capacitor (116), a power transmission circuit (130) for supplying AC power to the power transmission resonant circuit, a power transmission request signal receiving unit (172) for receiving a power transmission request signal transmitted from the power receiving device, and a switching unit (174) for switching the current value flowing through the power transmission coil, wherein, upon receiving the power transmission request signal, the switching unit changes the input impedance of the power transmission resonant circuit to a current value that can supply power to the power receiving device, and the power transmission request signal receiving unit is capable of receiving the power transmission request signal as a narrow-range communication signal with a communication distance of 5 meters or less. The device comprises a plurality of power transmission coils, which are arranged to form a single power transmission region (SC1, SC2) that is linear along one direction or planar between the intersecting direction and the one direction, and the power transmission request signal receiving unit is positioned near the end coils located at the end of the power transmission region among the plurality of power transmission coils. . A second embodiment of the present disclosure provides a power transmission device (100) for contactlessly supplying power to a movable power receiving device (200). The power transmission device includes a power transmission resonant circuit (110) having a power transmission coil (112) and a power transmission resonant capacitor (116), a power transmission circuit (130) for supplying AC power to the power transmission resonant circuit, a power transmission request signal receiving unit (172) for receiving a power transmission request signal transmitted from the power receiving device, and a switching unit (174) for switching the current value flowing through the power transmission coil, wherein when the power transmission request signal is received, the input impedance of the power transmission resonant circuit is changed to switch the power transmission The power transmission request signal receiving unit includes a switching unit that switches the current value flowing through the wire to a current value that can supply power to the power receiving device, and the power transmission request signal receiving unit is capable of receiving the power transmission request signal as a narrow-area communication signal with a communication distance of 5 meters or less, and further includes a wide-area communication unit (190) for receiving wide-area communication signals with a communication distance of more than 5 meters, and a power transmission side control unit (180) capable of driving the power transmission circuit, and the power transmission side control unit drives the power transmission circuit when the wide-area communication unit receives the wide-area communication signal. History of this disclosure 3 In this configuration, a power transmission device (100) is provided for non-contact power supply to a movable power receiving device (200). This power transmission device comprises a power transmission resonant circuit (110) having a power transmission coil (112) and a power transmission resonant capacitor (116), a power transmission circuit (130) for supplying AC power to the power transmission resonant circuit, a power transmission request signal receiving unit (172) for receiving a power transmission request signal transmitted from the power receiving device, and a switching unit (174) for switching the current value flowing through the power transmission coil, wherein when the power transmission request signal is received, the switching unit switches the current value flowing through the power transmission coil to a current value that can supply power to the power receiving device, and further comprises a plurality of the power transmission coils, wherein the plurality of power transmission coils are spaced apart from each other. The system comprises an adjacent power transmission resonant circuit (110Q) adjacent to the power transmission resonant circuit and having an adjacent power transmission coil (112Q) and an adjacent power transmission resonant capacitor (116Q), and an adjacent switching unit (320) that, when it detects a current flowing through the adjacent power transmission coil, changes the input impedance of the adjacent power transmission resonant circuit to switch the current value flowing through the adjacent power transmission coil to a current value that can supply power to the power receiving device. . A fourth embodiment of the present disclosure provides a power transmission device (100) for contactlessly supplying power to a movable power receiving device (200). This power transmission device includes a power transmission resonant circuit (110) having a power transmission coil (112) and a power transmission resonant capacitor (116), a power transmission circuit (130) for supplying AC power to the power transmission resonant circuit, a power transmission request signal receiving unit (172) for receiving a power transmission request signal transmitted from the power receiving device, and a switching unit (174) for switching the current value flowing through the power transmission coil, wherein when the power transmission request signal is received, the input impedance of the power transmission resonant circuit is changed to switch the current value flowing through the power transmission coil to a current value that can supply power to the power receiving device. The power transmission request signal receiving unit is capable of receiving the power transmission request signal as a narrow-range communication signal with a communication distance of 5 meters or less, and includes an adjacent power transmission resonant circuit (110Q) adjacent to the power transmission resonant circuit and having an adjacent power transmission coil (112Q) and an adjacent power transmission resonant capacitor (116Q), and an adjacent switching unit (320) that, when it detects a current flowing through the adjacent power transmission coil, changes the input impedance of the adjacent power transmission resonant circuit to switch the value of the current flowing through the adjacent power transmission coil to a value of current that can be supplied to the power receiving device. These forms of power transmission devices can suppress or prevent problems such as the failure to start supplying power from the power transmission device to the power reception device when the power receiving device changes from a non-facing state to a facing state relative to the power transmission device. [Brief explanation of the drawing]

[0007] [Figure 1] An explanatory diagram showing a contactless power supply system equipped with a power transmission device according to the first embodiment. [Figure 2] An explanatory diagram showing the circuit configuration of a contactless power supply system. [Figure 3] An explanatory diagram showing the circuit configuration of a power transmission resonant circuit located at the edge of the power transmission area. [Figure 4] An explanatory diagram showing the circuit configuration of a power transmission resonant circuit located within the power transmission area. [Figure 5] An explanatory diagram showing the switching process for power transmission equipment. [Figure 6] A flowchart illustrating the processing routine for transitioning a power transmission device to a standby state. [Figure 7] A flowchart illustrating the processing routine for transitioning a power transmission device to a powered state. [Figure 8] A flowchart illustrating the processing routine for transitioning power transmission equipment to a shutdown state. [Figure 9] The first explanatory diagram shows the relationship between a moving vehicle and a power transmission device. [Figure 10] A second explanatory diagram showing the relationship between a moving vehicle and a power transmission device. [Figure 11] A third explanatory diagram showing the relationship between a moving vehicle and a power transmission device. [Figure 12] A fourth explanatory diagram showing the relationship between a moving vehicle and a power transmission device. [Figure 13] A fifth explanatory diagram showing the relationship between a moving vehicle and a power transmission device. [Figure 14] A sixth explanatory diagram showing the relationship between a moving vehicle and a power transmission device. [Figure 15] An explanatory diagram showing the configuration of a power transmission device as another embodiment. [Figure 16] An explanatory diagram showing the configuration of a power receiving device as another embodiment. [Description of Embodiments]

[0008] A. First Embodiment: FIG. 1 is a schematic configuration diagram showing a contactless power supply system including a power transmitting device 100 according to the first embodiment of the present disclosure. The contactless power supply system includes the power transmitting device 100 and a power receiving device 200, and is a system capable of contactlessly supplying electric power from the power transmitting device 100 to the power receiving device 200. X, Y, and Z shown in FIG. 1 and each subsequent figure represent three mutually orthogonal spatial axes. In this specification, the directions along these axes are also referred to as the X-axis direction, Y-axis direction, and Z-axis direction. In the example of FIG. 1, the X-axis direction matches the traveling direction of the vehicle CR along the lane of the vehicle travel path RS, the Y-axis direction matches the width direction of the vehicle travel path RS, and the Z-axis direction matches the direction of gravity.

[0009] The power transmitting device 100 includes a power transmitting resonant circuit 110, a power transmitting circuit 130, and a power supply circuit 140. In the present embodiment, the power transmitting resonant circuit 110, the power transmitting circuit 130, and the power supply circuit 140 are embedded inside the vehicle travel path RS. However, the power transmitting resonant circuit 110, the power transmitting circuit 130, and the power supply circuit 140 are not limited to being inside the vehicle travel path RS, and may be exposed on the vehicle travel path RS. The power transmitting circuit 130 and the power supply circuit 140 may be arranged, for example, on a side road, or may be arranged at a position on the vehicle travel path RS that does not hinder the traveling of the vehicle CR.

[0010] The power supply circuit 140 is, for example, an AC / DC converter circuit, which converts AC power from an AC power source such as a system power source into DC power and supplies the DC power to the power transmitting circuit 130. The power transmitting circuit 130 is a device including an inverter or the like that converts the DC power supplied from the power supply circuit 140 into AC power of an operating frequency and supplies the AC power to the power transmitting resonant circuit 110. The power transmitting circuit 130 may include a rectifier circuit, a filter circuit, and the like.

[0011] The power transmission resonance circuit 110 transmits the AC power induced in the power transmission coil 112 using the electromagnetic induction phenomenon to the power reception resonance circuit 210. As shown in Figure 1, a plurality of power transmission resonance circuits 110, specifically four power transmission resonance circuits 110P, 110Q, 110R, 110S, are continuously laid in a straight line along the traveling direction (X-axis direction) of the vehicle CR on the vehicle travel path RS. The power transmission resonance circuits 110P, 110Q, 110R, 110S are arranged in contact with each other. Further, one power transmission circuit 130 is provided for the four power transmission resonance circuits 110P, 110Q, 110R, 110S. Thereby, the single power transmission circuit 130 and the plurality of power transmission resonance circuits 110 form one power transmittable region SC1 arranged in a substantially straight line. In the example of Figure 1, at a position separated by a predetermined distance from the power transmittable region SC1, a power transmittable region SC2 configured similarly to the power transmittable region SC1 is further provided.

[0012] As shown in Figure 2, the power transmission resonance circuit 110 is a resonance circuit in which a power transmission coil 112 and a power transmission resonance capacitor 116 functioning as a resonance capacitor are connected in series. The power transmission resonance capacitor 116 is a resonance capacitor for resonating the power supplied to the power transmission coil 112. For the power transmission resonance capacitor 116, a unit capable of varying the magnitude of capacitance is used, as will be described later. In the following description, the AC voltage applied by the power transmission circuit 130 to the power transmission resonance circuit 110 is denoted as V1, the AC current as I1, the operating frequency as f0, and the operating angular frequency as ω0 (=2π·f0). The power transmission coil 112 and the power transmission resonance capacitor 116 may be connected in parallel.

[0013] When power is supplied from the power transmission device 100 to the power receiving device 200, the capacitance C1 is set to a value such that the input impedance Z1(V1 / I1) of the power transmission resonant circuit 110 is small, and a large coil current for power supply flows through the power transmission coil 112. When power is not supplied from the power transmission device 100 to the power receiving device 200, the capacitance C1 is set to a value such that the input impedance Z1 of the power transmission resonant circuit 110 is large, and a small coil current for standby flows through the power transmission coil 112.

[0014] Here, the input impedance Z1 can be simply expressed as Z1 = j[ω0·L1-1 / (ω0·C1)], where L1 is the self-inductance of the transmission coil 112. Therefore, to reduce the input impedance Z1, the capacitance C1 should be set such that the absolute value of [ω0·L1-1 / (ω0·C1)] equals a predetermined impedance. To increase the input impedance Z1, the capacitance C1 should be set smaller than when reducing the input impedance Z1, so that it corresponds to a predetermined standby current impedance. As described above, when reducing the input impedance Z1, the capacitance C1 is set to the capacitance for power supply, and when increasing the input impedance Z1, the capacitance C1 is set to the capacitance for standby.

[0015] The capacitance C1 of the power transmission resonant capacitor 116 during power supply is, for example, calculated with respect to the self-inductance L1 of the power transmission coil 112, such that the operating frequency f0 becomes the resonant frequency, C1 = 1 / (ω0 2It is set to L1). In addition, the capacitance C1 during power supply may be set so that the resonant frequency is the xth harmonic of the operating frequency f0 (where x is a positive number of 2 or more). That is, the capacitance C1 during power supply may be set according to various predetermined setting conditions, based on the self-inductance L1 of the transmission coil 112, the operating frequency f0 (operating angular frequency ω0), etc., so that AC power at the operating frequency f0 is efficiently transmitted between the transmission resonant circuit 110 and the receiving resonant circuit 210. The capacitance C1 when not powered is set to a value that is sufficiently small compared to the capacitance C1 during power supply, so that the input impedance Z1 corresponds to a predetermined standby current.

[0016] As shown in Figure 1, the power receiving device 200 is mounted on various devices that operate using electricity, such as electronic devices and electric vehicles. In this embodiment, the power receiving device 200 is mounted on a vehicle CR. A vehicle CR is, for example, a vehicle equipped with a drive motor that uses electricity as power, such as an electric vehicle or a hybrid vehicle. The power receiving device 200 comprises a power receiving resonant circuit 210, a power receiving circuit 220, a battery 230, and a power receiving side narrow-range communication unit 270.

[0017] The power receiving resonant circuit 210 is located, for example, on the bottom surface of the vehicle CR. The power receiving resonant circuit 210 includes a power receiving coil 212. The power receiving resonant circuit 210 is a circuit for obtaining AC power induced in the power receiving coil 212 in a resonant coupling state in which the power receiving coil 212 and the power transmitting coil 112 are magnetically coupled. The power receiving coil 212 is installed on the bottom surface of the vehicle CR in a position that can face the power transmitting coil 112 of the power transmitting resonant circuit 110. The power induced in the power receiving resonant circuit 210 is charged into the battery 230 via the power receiving circuit 220 and used to drive a motor (not shown), etc.

[0018] As shown in Figure 2, the power receiving resonant circuit 210, like the power transmitting resonant circuit 110, is a resonant circuit having a power receiving coil 212 and a power receiving resonant capacitor 216 connected in series. The power receiving resonant circuit 210 is a device that obtains AC power induced in the power receiving coil 212. Specifically, the power receiving resonant circuit 210 receives AC power from the power transmitting device 100 in a non-contact manner by resonating with the power transmitting resonant circuit 110. When the power receiving coil 212 is in a facing state with respect to the power transmitting coil 112, the power transmitting coil 112 and the power receiving coil 212 are electromagnetically coupled and resonate with the power transmitting resonant circuit 110. As shown in Figure 2, the power transmitting resonant circuit 110 and the power receiving resonant circuit 210 employ a resonance method using a primary series and secondary series capacitor (also called the "SS method"). Furthermore, a single-phase transmission-single-phase non-contact power supply system is applied, where the transmitting side is composed of a single-phase transmission coil 112 and the receiving side is composed of a single-phase receiving coil 212. The inductance of the transmission coil 112 is represented by Lt, and the capacitance of the transmission resonant capacitor 116 is represented by Ct. The inductance of the receiving coil 212 is represented by Lr, and the capacitance of the receiving resonant capacitor 216 is represented by Cr.

[0019] The power receiving circuit 220 converts the AC power output from the power receiving resonant circuit 210 into DC power. The DC power output from the power receiving circuit 220 can be used for charging the battery 230, etc. The power receiving circuit 220 includes, for example, a filter circuit, a rectifier circuit that converts AC power into DC power, and a power conversion circuit that converts the AC power into DC power suitable for charging the battery 230. The battery 230 is, for example, a secondary battery that outputs DC power to drive a drive motor, which is the power source for the vehicle CR. The DC power from the power receiving circuit 220 may also be used to charge an auxiliary battery (not shown) or to drive the drive motor or auxiliary equipment.

[0020] As shown in Figure 1, the transmitting coil 112 receives AC power from the transmission circuit 130 when the receiving coil 212 is facing it. The transmitting coil 112 and the receiving coil 212 then electromagnetically couple, transmitting AC power from the transmitting coil 112 to the receiving coil 212. The AC power transmitted to the receiving coil 212 is then used to charge the battery 230 via the receiving circuit 220. In contrast, when the receiving coil 212 is not facing the transmitting coil 112, AC power is not supplied from the transmission circuit 130, as will be described later.

[0021] The capacitance C2 of the power receiving resonant capacitor 216 is determined, similar to the capacitance C1 during power supply, by C2 = 1 / (ω0) with respect to the self-inductance L2 of the power receiving coil 212, such that the operating frequency f0 becomes the resonant frequency. 2 The capacitance C2 is set to L2). The capacitance C2 may also be set considering the coupling coefficient between the transmitting coil 112 and the receiving coil 212. The capacitance C2 may also be set so that the resonant frequency is the x-th harmonic frequency of the operating frequency f0. In other words, the capacitance C2 may be set according to various predetermined setting conditions, based on the self-inductance L2 of the receiving coil 212, the operating frequency f0 (operating angular frequency ω0), the coupling coefficient, etc., so that AC power at the operating frequency f0 is efficiently transmitted between the transmitting resonant circuit 110 and the receiving resonant circuit 210.

[0022] The receiving-side narrow-area communication unit 270 functions as a power transmission request signal transmitter that transmits a power transmission request signal to the power transmission device 100 via narrow-area communication. The "power transmission request signal" is a signal used to switch the power transmission device 100 to a powered state where it can supply power. In this embodiment, the power transmission request signal includes vehicle CR location information and ID information. The "vehicle CR location information included in the power transmission request signal" means that, based on the establishment of narrow-area communication between the receiving-side narrow-area communication unit 270 as an RF tag and the power transmission-side narrow-area communication unit 170, the vehicle CR has been detected within a predetermined distance from the power transmission-side narrow-area communication unit 170. However, it is not limited to this, and the "vehicle CR location information included in the power transmission request signal" may also include information on the absolute position of the vehicle CR and information on the relative position of the vehicle CR with respect to the power transmission device 100. The "ID information" is identification information of the vehicle CR equipped with the power receiving device 200. However, the identification information is not limited to that of the vehicle CR, but may also include the identification information of the receiving coil 212 included in the receiving device 200, or the identification information of the user of the receiving device 200, or a combination of these, or various other identification information associated therewith. In this disclosure, "narrow-area communication" means wireless communication with a communication distance of 5 meters or less. The communication distance in narrow-area communication is more preferably about 1 to 100 centimeters, from the viewpoint of improving the identifiability of a single vehicle CR to multiple moving vehicles, improving the electromagnetic compatibility (EMC) of the power transmission device 100, and suppressing unnecessary power consumption and the generation of unnecessary magnetic flux when the receiving device 200 is not facing the transmission device.

[0023] In this embodiment, the receiving-side narrow-area communication unit 270 employs an active-type RF-ID (Radio Frequency-Identification) tag that utilizes radio wave methods in the 900 MHz band or 2.45 GHz band. In the following description, the RF-ID tag will also be referred to as the "RF tag". By employing an active-type RF-ID, the receiving-side narrow-area communication unit 270 can perform periodic communication at predetermined intervals and periodically transmit power transmission request signals. However, the receiving-side narrow-area communication unit 270 may also be a passive-type RF tag. The receiving-side narrow-area communication unit 270 may also be an electromagnetic induction-type RF tag instead of a radio wave-type RF tag. Furthermore, the receiving-side narrow-range communication unit 270 is not limited to RF-ID tags, but may also be, for example, a short-range wireless communication technology using a loop antenna, or a short-range wireless communication technology that applies "Wavelet OFDM (Orthogonal Frequency-Division Multiplexing)" as an orthogonal frequency division multiplexing method to a communication method using a magnetic field, or wireless communication using a bidirectional wireless communication method using the 5.8GHz band such as DSRC (Dedicated Short Range Communication).

[0024] As shown in Figure 1, in this embodiment, the vehicle CR further includes a vehicle information acquisition unit 260, a vehicle control unit 280, and a power receiving side wide-area communication unit 290. The vehicle control unit 280 is a circuit including a CPU and memory. The vehicle control unit 280 controls the various parts of the power receiving device 200 and the vehicle CR. The vehicle control unit 280 performs various controls for the operation of the vehicle CR and is used in both automatic and manual operation. The memory stores various programs for realizing the functions provided in this embodiment, and the vehicle control unit 280 realizes the functions of each part by executing the computer programs stored in the memory by the CPU. Note that some of the functions of the vehicle control unit 280 may be realized by hardware circuits.

[0025] The vehicle information acquisition unit 260 acquires various support information related to the contactless power supply system and the driving of the vehicle CR. The vehicle information acquisition unit 260 includes a GNSS receiver 262 and a navigation device 264. The GNSS receiver 262 determines the current position (longitude and latitude) of the vehicle CR based on navigation signals received from artificial satellites that constitute the GNSS (Global Navigation Satellite System). The navigation device 264 has the function of determining the planned driving route based on the destination and the vehicle's position detected by the GNSS receiver 262. In addition to the GNSS receiver 262, other sensors such as a gyroscope may be used to determine or modify the planned driving route.

[0026] The receiving-side wide-area communication unit 290 applies to the power transmission device 100 for a reservation of use of the power transmission device 100 via wide-area communication. Specifically, the receiving-side wide-area communication unit 290 transmits to the power transmission device 100 the information necessary for applying for a reservation of use of the power transmission device 100, such as the vehicle CR's current position, planned route, and vehicle CR's ID information. For example, the same information as the ID information transmitted by the receiving-side narrow-area communication unit 270 described above is used for the vehicle CR's ID information.

[0027] "Wide-area communication" refers to wireless communication where the communication distance is wider than that of narrow-area communication, which will be described later. Wide-area communication can be realized by, for example, mobile communication systems such as fifth-generation mobile communication systems (5G, Local 5G), fourth-generation mobile communication systems (LTE-Advanced, 4G), LTE, wireless local networks (LANs) compliant with the IEEE 802.11 standard, and wireless communication using Bluetooth®. Wireless communication with the power transmission device 100 includes indirect wireless communication with the power transmission device 100 via base stations, servers, etc.

[0028] In this embodiment, the power transmission device 100 further includes a power transmission side narrow-area communication unit 170, a power transmission side control unit 180, and a power transmission side wide-area communication unit 190. The power transmission side wide-area communication unit 190 receives usage reservation applications from vehicle CR via wide-area communication. The information acquired by the power transmission side wide-area communication unit 190 is output to the power transmission side control unit 180. The power transmission side control unit 180 is a circuit including a CPU and memory. Based on the information received from vehicle CR via the power transmission side wide-area communication unit 190, the power transmission side control unit 180 switches the current value flowing through the power transmission coil 112 by changing the input impedance Z1 of the power transmission resonant circuit 110, thereby switching the power transmission device 100 between a stopped state and a standby state. The "stopped state of the power transmission device 100" means a state in which the power supply from the power transmission circuit 130 to the power transmission resonant circuit 110 is stopped because the drive of the power transmission circuit 130 is stopped. "The standby state of the power transmission device 100" refers to a state in which the power transmission circuit 130 is driven, but no power is supplied to the power receiving device 200. In the standby state of the power transmission device 100, the input impedance Z1 of the power transmission resonant circuit 110 is large, and a small standby coil current flows through the power transmission coil 112.

[0029] The transmitting-side narrow-area communication unit 170 is an interface for receiving power transmission request signals and the like transmitted from the receiving-side narrow-area communication unit 270 via narrow-area communication, and for changing the input impedance Z1 of the power transmission resonant circuit 110 based on the received power transmission request signals. As shown in Figure 1, the transmitting-side narrow-area communication unit 170 includes a receiving unit 172 and a switching unit 174.

[0030] The receiving unit 172 acquires power transmission request signals and the like transmitted from the power receiving side narrow-area communication unit 270. The receiving unit 172 can use, for example, a reader that corresponds to the wireless communication method used by the power receiving side narrow-area communication unit 270. In this embodiment, the receiving unit 172 employs an RF reader capable of recognizing RF tags. However, the receiving unit 172 can also be a receiver that corresponds to the magnetic field communication method using the loop antenna described above.

[0031] The switching unit 174 is a circuit for switching the current value flowing through the power transmission resonant circuit 110. Specifically, when the receiving unit 172 acquires a power transmission request signal from the receiving-side narrow-area communication unit 270, the switching unit 174 changes the input impedance Z1 of the power transmission resonant circuit 110 by switching a switch circuit or the like provided in the power transmission resonant circuit 110, thereby switching the current value flowing through the power transmission coil 112 to a current value that can supply power to the power receiving device 200. In this embodiment, the switching unit 174 is, for example, located at the center of the power transmission coil 112 and is provided integrally with the power transmission coil 112. The receiving unit 172 functions as a power transmission request signal receiving unit that receives the power transmission request signal.

[0032] As shown in Figure 1, in this embodiment, the transmission-side narrow-area communication unit 170 is positioned near the transmission resonant circuit 110, which is located at the end of the transmission-enabled region SC1, among the four transmission resonant circuits 110P, 110Q, 110R, and 110S included in the transmission-enabled region SC1. Here, "end of the transmission-enabled region SC1" means the end in the arrangement of the multiple transmission resonant circuits that form the transmission-enabled region SC1. The transmission coil included in the transmission resonant circuit located at the end of the transmission-enabled region SC1 is also called the "end coil". In the example in Figure 1, among the four transmission resonant circuits 110P, 110Q, 110R, and 110S arranged linearly in the transmission-enabled region SC1, transmission resonant circuits 110P and 110S correspond to the transmission resonant circuit 110 located at the end of the transmission-enabled region SC1. Furthermore, in this embodiment, the transmission-side narrow-area communication unit 170 is positioned only near the end coil 112P, which is the first end coil to intersect when the vehicle CR travels along its travel path, when the vehicle CR travels along the vehicle travel path RS and the power transmission area SC1 are superimposed. From the viewpoint of improving the identifiability of a single vehicle CR to multiple vehicles traveling, improving the electromagnetic compatibility (EMC) of the power transmission device 100, and suppressing unnecessary power consumption and the generation of unnecessary magnetic flux in non-facing states with the power receiving device 200, it is preferable to be able to detect with high accuracy when a vehicle CR is close to the end coil 112P. For this reason, it is preferable that the installation position of the receiving unit 172 is close to the installation position of the end coil 112P, and it is even more preferable that the coordinates of the receiving unit 172 and the end coil 112P overlap in a plan view, for example, by positioning the receiving unit 172 within the coil plane of the end coil 112P.

[0033] The method for switching the current value flowing through the power transmission resonant circuit 110 will be explained using Figures 3 and 4. In the power transmission resonant circuit 110P having an end coil 112P, as shown in Figure 3, the power transmission resonant capacitor 116P is a unit using multiple capacitors 116Pa, 116Pb and a bidirectional switch circuit 117. Note that in Figures 3 and 4, for the sake of ease of understanding the technology, only the power transmission resonant circuit 110P, the power transmission side narrow-range communication unit 170, and the current sensor 310 from the components of the power transmission device 100 shown in Figure 2 are shown, and other components are omitted.

[0034] The transmission-side narrow-range communication unit 170 changes the input impedance Z1 using the transmission resonant capacitor 116P and the transmission-side narrow-range communication unit 170. Specifically, the switching unit 174 changes the input impedance Z1 by switching the bidirectional switch circuit 117 of the transmission resonant capacitor 116P, thereby changing the capacitance value of the transmission resonant capacitor 116P.

[0035] As shown in Figure 3, the power transmission resonant capacitor 116P has a first resonant capacitor 116Pa and a second resonant capacitor 116Pb arranged in parallel. However, the second resonant capacitor 116Pb is connected in parallel with the first resonant capacitor 116Pa when the bidirectional switch circuit 117 connected in series is ON, and is disconnected when the bidirectional switch circuit 117 is OFF. The capacitance Ct of the power transmission resonant capacitor 116P is the capacitance Chs of the first resonant capacitor 116Pa when the bidirectional switch circuit 117 is OFF, and is the product of the capacitance Chs of the first resonant capacitor 116Pa and the capacitance Chl of the second resonant capacitor 116Pb (Chs + Chl) when the bidirectional switch circuit 117 is ON.

[0036] The switching unit 174 switches the bidirectional switch circuit 117 based on the ID information and power transmission request signal received by the receiving unit 172 from the receiving-side narrow-area communication unit 270. As a result, the capacitance Ct of the power transmission resonant capacitor 116P is switched. When the receiving unit 172 acquires the power transmission request signal, the switching unit 174 turns on the bidirectional switch circuit 117 and reduces the input impedance Z1 of the power transmission resonant circuit 110 to Z1=Z1r. This allows power to be supplied from the power transmission device 100 to the power receiving device 200. Hereinafter, the state in which power can be supplied from the power transmission device 100 to the power receiving device 200 will also be referred to as the "powered state of the power transmission device 100".

[0037] When the switching unit 174 is in a non-facing state where it is not supplying power from the power transmission device 100 to the power receiving device 200, it turns off the bidirectional switch circuit 117 and increases the input impedance Z1 of the power transmission resonant circuit 110 so that Z1 = Z1n > Z1r. As a result, the power supply from the power transmission device 100 to the power receiving device 200 is stopped, and the power transmission device 100 can be put into a standby state. As shown in Figure 1, the power transmission side narrow-range communication unit 170 is connected to the current sensor 310. For example, when the power receiving coil 212 and the power transmission coil 112 are in a non-facing state and the current value flowing through the current sensor 310, i.e., the current value flowing through the power transmission coil 112, falls below a predetermined threshold, the switching unit 174 can detect this and turn off the bidirectional switch circuit 117 to stop the power supply. Alternatively, the switching unit 174 can detect that the narrow-area communication between the receiving unit 172 and the power-receiving narrow-area communication unit 270 has been interrupted, and then turn off the bidirectional switch circuit 117 to stop the power supply. The current sensor 310 is an example of a "power-transmitting detection circuit".

[0038] As shown in Figure 4, the power transmission resonant circuit 110Q adjacent to the power transmission resonant circuit 110P changes the input impedance Z1 using a power transmission resonant capacitor 116Q as a unit using multiple capacitors 116Qa, 116Qb and a bidirectional switch circuit 117, and a variable control circuit 320. The configuration of the power transmission resonant capacitor 116Q is the same as that of the power transmission resonant capacitor 116P, so its explanation is omitted.

[0039] The variable control circuit 320 can control the capacitance Ct of the power transmission resonant capacitor 116Q according to the opposing state of the power receiving coil 212 and the power transmission coil 112. The variable control circuit 320 includes a current sensor 322, a rectifier circuit 324, a low-pass filter circuit 326 (hereinafter also referred to as "LPF circuit 326"), and a voltage conversion circuit 328. In the following description, when the end coil 112P and the power transmission coils 112Q, 112R, and 112S are not distinguished, they will be referred to as "power transmission coil 112".

[0040] The current sensor 322 detects the current flowing through the power transmission coil 112Q and outputs it as a detected voltage. The current detected by the current sensor 322 is very small when the power receiving coil 212 is not facing the power transmission coil 112, and increases as it moves from a non-facing state to a facing state and approaches a direct facing state. The detected voltage changes according to the change in the current in the current sensor 322. If the voltage output based on the current value flowing through the current sensor 322 becomes smaller than a predetermined threshold, the bidirectional switch circuit 117 can be turned off to stop the power supply. The current sensor 322 is an example of a "power transmission side detection circuit". The rectifier circuit 324 rectifies the detected voltage. The LPF circuit 326 removes the high-frequency components of the detected voltage. The voltage conversion circuit 328 is a circuit using a comparator that outputs different control voltages Vs based on whether the detected voltage Vd is greater than or equal to a threshold voltage Vth.

[0041] When the voltage conversion circuit 328 detects that the detected voltage Vd is smaller than the threshold voltage Vth due to the non-opposing state, it outputs a control voltage Vs that turns off the bidirectional switch circuit 117. As a result, the input impedance Z1 of the power transmission resonant circuit 110Q is increased so that Z1 = Z1n > Z1r, and similarly, the power supply from the power transmission device 100 to the power receiving device 200 can be stopped in the non-opposing state at the power transmission resonant circuit 110Q adjacent to the power transmission resonant circuit 110P at the end.

[0042] The voltage conversion circuit 328 outputs a control voltage Vs that turns on the bidirectional switch circuit 117 when the detected voltage Vd is detected as a value equal to or higher than the voltage Vth serving as a threshold value due to the facing state. As a result, the input impedance Z1 of the power transmission resonant circuit 110Q is reduced to Z1=Z1r, the input impedance Z1 input to the power transmission resonant circuit 110Q is reduced to Z1=Z1r, and similarly, in the power transmission resonant circuit 110Q adjacent to the end power transmission resonant circuit 110P, power supply from the power transmission device 100 to the power reception device 200 can be started in the facing state.

[0043] The capacitance Ct of the power transmission resonant capacitor 116Q becomes the capacitance Chs of the first resonant capacitor 116Qa in the non-facing state, and becomes the integrated value (Chs+Chl) of the capacitance Chs of the first resonant capacitor 116Qa and the capacitance Chl of the second resonant capacitor 116Qb in the facing state. The capacitance Chs of the first resonant capacitor 116Qa and the capacitance Chl of the second resonant capacitor 116Qb may be set such that the capacitance Ct=(Chs+Chl) in the facing state is the resonant capacitance C1, the capacitance Ct=Chs in the non-facing state is smaller than the resonant capacitance C1, and Chs<Chl.

[0044] The power supply processing executed by the power transmission device 100 of the present embodiment will be described using FIGS. 5 to 14. FIGS. 9 to 14 show a state in which the vehicle CR equipped with the power reception device 200 travels toward the power transmittable region SC1 of the power transmission device 100 and passes through the power transmittable region SC1. In FIGS. 9 to 14, for convenience of illustration, the power transmission side short-range communication unit 170 is shown spaced apart from the end coil 112P, but in practice, the coordinates of the end coil 112P and the power transmission side short-range communication unit 170 coincide with each other in a plan view. Note that in FIGS. 9 to 14, hatching is applied to portions in a functionally active state to facilitate understanding of the technology. In addition, in FIGS. 9 to 14, the names of some components are abbreviated for convenience of illustration.

[0045] Figures 9 to 14 schematically show the energization start distance DT2 and the preparation distance DT1 from the end coil 112P of the power transmission device 100. The energization start distance DT2 can be set using, for example, the distance at which power transmission request signals can be exchanged between the receiving-side narrow-area communication unit 270 of the power receiving device 200 and the transmitting-side narrow-area communication unit 170 of the power transmission device 100. In this embodiment, the energization start distance DT2 is set to 100 centimeters, which is the communication distance of the receiving-side narrow-area communication unit 270. The preparation distance DT1 is a longer distance than the energization start distance DT2 and defines the area for transitioning the power transmission device 100 to a ready state upon the entry of a vehicle CR. The preparation distance DT1 can be determined by the time the vehicle CR travels a distance equal to the preparation distance DT1 minus the power supply start distance DT2 (DT1-DT2), during which time the power transmission circuit 130 should be able to enter a standby state. For example, this can be derived from the time required to transition the power transmission circuit 130 to the preparation state, the distance between the vehicle CR and the power transmission device 100, and the travel speed of the vehicle CR.

[0046] As shown in Figure 5, in the power supply process from the power transmission device 100 to the power receiving device 200, in step S10, the stopped power transmission device 100 transitions to a standby state. Specifically, as shown in Figure 6, in step S110, the vehicle CR starts an application to reserve the use of the power transmission device 100. Reservation of the use of the power transmission device 100 means applying to the power transmission device 100 or the administrator of the power transmission device 100 for the use of the power transmission device 100 to supply power from the power transmission device 100 to the power receiving device 200. The reservation of the use of the power transmission device 100 may be made, for example, by the vehicle control unit 280 which has obtained information from the vehicle information acquisition unit 260 that the planned driving route generated by the navigation device 264 includes a power transmission area SC1, or it may be made manually by the user of the vehicle CR. Alternatively, regardless of whether a reservation request has been made from the vehicle CR, the power transmission device 100 may accept the reservation request if it detects that the vehicle CR is within a predetermined range from the power transmission device 100 based on the location information of the vehicle CR transmitted from the vehicle CR via the receiving-side wide-area communication unit 290. The vehicle control unit 280 may also request a reservation request from the power transmission device 100 depending on the charge status of the battery 230, for example, by determining that the State of Charge (SOC) of the battery 230 is low.

[0047] When an application for a reservation to use the power transmission device 100 is initiated, in step S120, as shown in Figure 9, the vehicle control unit 280 of the vehicle CR transmits the vehicle CR's location information and vehicle CR's ID information along with the application for the reservation to use via the receiving-side wide-area communication unit 290. This information may be transmitted periodically at predetermined intervals after the start of the application. The vehicle CR's location information transmitted via wide-area communication is the vehicle CR's current location information acquired by the GNSS receiver 262 or the navigation device 264. However, the vehicle CR's location information transmitted via wide-area communication may also include information that the vehicle CR has been detected within a predetermined distance from the transmitting-side wide-area communication unit 190 based on the establishment of wide-area communication between the receiving-side wide-area communication unit 290 and the transmitting-side wide-area communication unit 190, as well as information on the vehicle CR's relative position to the transmitting-side wide-area communication unit 190.

[0048] In step S130, when the transmission-side wide-area communication unit 190 of the power transmission device 100 acquires the vehicle CR's current location information and vehicle CR's ID information, the transmission-side control unit 180 accepts the vehicle CR's application for reservation to use the power transmission device 100 and stores the acquired vehicle CR's ID information in memory.

[0049] In step S140, the power transmission control unit 180 uses the acquired current position information of the vehicle CR to determine whether the vehicle CR has reached the range from the end coil 112P to the preparation distance DT1. If the distance from the end coil 112P to the vehicle CR is greater than or equal to the preparation distance DT1 (S140: NO), the power transmission control unit 180 continues to acquire the current position information of the vehicle CR and waits until the vehicle CR reaches the range from the end coil 112P to the preparation distance DT1. If the distance from the end coil 112P becomes shorter than the preparation distance DT1 (S140: YES), the power transmission control unit 180 proceeds to step S150 and, as shown in Figure 10, drives the power transmission circuit 130 to switch from the stopped state to the standby state, thereby completing the process.

[0050] Returning to Figure 5, in step S20, the power transmission device 100, which is in standby mode, transitions to a powered-on state. Specifically, as shown in Figure 7, in step S210, the power transmission control unit 180 uses the acquired current position information of the vehicle CR to determine whether the vehicle CR has reached the range from the end coil 112P to the power supply start distance DT2. If the distance from the end coil 112P to the vehicle CR is greater than or equal to the power supply start distance DT2 (S210: NO), the power transmission control unit 180 continues to acquire the current position information of the vehicle CR and waits until the vehicle CR reaches the range from the end coil 112P to the power supply start distance DT2. If the distance from the end coil 112P becomes shorter than the power supply start distance DT2 (S210: YES), the power transmission control unit 180 proceeds to step S220.

[0051] In step S220, the vehicle control unit 280 receives a request from the power transmission device 100 via the power transmission side narrow-area communication unit 170 and initiates an application to start power supply. The vehicle control unit 280 may also initiate an application to start power supply when the current position of the vehicle CR reaches the range up to the power supply start distance DT2. In step S230, as an application to start power supply, the vehicle control unit 280 transmits the vehicle CR's position information and the vehicle CR's ID information via narrow-area communication by the power receiving side narrow-area communication unit 270, based on the establishment of narrow-area communication.

[0052] In step S240, the receiving unit 172 of the transmitting-side narrow-area communication unit 170 acquires the location information of the vehicle CR and the ID information of the vehicle CR transmitted from the receiving-side narrow-area communication unit 270. In step S250, the transmitting-side control unit 180 compares the ID information of the vehicle CR stored in memory in the application for reservation of use of the power transmission device 100 described above with the ID information of the vehicle CR acquired via the receiving-side narrow-area communication unit 270. If the ID information of the vehicle CRs matches, the transmitting-side control unit 180 approves the application for commencement of power supply and proceeds to step S260.

[0053] As shown in Figure 11, when the vehicle CR moves along the X-axis direction, which is the direction of travel, the vehicle CR may first pass through the end coil 112P in the power transmission area SC1. The vehicle CR transmits its position information, i.e., that the vehicle CR is in close proximity to the end coil 112P, to the power transmission device 100 via the receiving-side narrow-area communication unit 270, and also completes a power supply start request using ID information.

[0054] In step S260, the power transmission control unit 180 transitions the power transmission device 100 from standby to energized. Specifically, the power transmission control unit 180 controls the switching unit 174 to turn on the bidirectional switch circuit 117 of the power transmission resonant circuit 110P of the end coil 112P. As a result, the input impedance Z1 of the power transmission resonant circuit 110P is changed to a small value, and a large current for power supply flows through the end coil 112P. The power transmission control unit 180 terminates the process after switching the power transmission device 100 to the energized state.

[0055] As shown in Figure 12, the vehicle CR completes the power supply start request while moving and reaches the end coil 112P, which is already receiving power. When the receiving coil 212 approaches the end coil 112P and faces it, the magnetic flux G2 generated from the end coil 112P induces a magnetic flux G1 in the receiving coil 212 through resonance, resulting in magnetic coupling. As a result, power supply from the power transmission device 100 to the power receiving device 200 begins.

[0056] As the vehicle CR continues to travel, as shown in Figure 13, after power supply begins due to the magnetic coupling between the magnetic flux G1 of the receiving coil 212 and the magnetic flux G2 of the end coil 112P, current flows from the receiving coil 212 to the transmitting coil 112Q adjacent to the end coil 112P via the magnetic flux G3. The variable control circuit 320 of the transmitting resonant circuit 110Q detects this current flowing through the transmitting coil 112Q and turns on the bidirectional switch circuit 117 of the transmitting resonant circuit 110Q. The input impedance Z1 of the transmitting resonant circuit 110Q is changed to a small value, and a large current for power supply flows through the transmitting coil 112Q. As a result, power supply begins due to the magnetic coupling between the transmitting coil 112Q adjacent to the end coil 112P and the receiving coil 212. Thus, after power supply is initiated at the end of the power transmission area SC1 by the end coil 112P, the transmission coil 112Q adjacent to the end coil 112P, and the transmission coils 112R and 112S continuous with it, can begin supplying power without using narrow-area communication.

[0057] Returning to Figure 5, in step S30, the power transmission device 100, which is currently energized, transitions to a stopped state and the process is completed. As shown in Figure 8, in step S310, the power transmission control unit 180 confirms that power supply has ended for each power transmission area SC1. In the example in Figure 14, the power transmission control unit 180 confirms that power supply by all power transmission resonant circuits 110 included in the power transmission area SC1 has ended.

[0058] In this embodiment, the power transmission control unit 180 confirms the end of power supply by confirming that the current value flowing through the power transmission coil 112 becomes smaller than the current value during power supply. Specifically, the power transmission control unit 180 determines that power supply by all power transmission resonant circuits 110 included in the power transmission area SC1 has ended when the detected value of the current sensor 310 in the end coil 112P falls below a predetermined threshold, and similarly when the detected values ​​of the current sensors 322 in the other power transmission coils 112Q, 112R, and 112S fall below a predetermined threshold. At this point, as the vehicle CR moves, the power receiving device 200 moves away from the power transmission device 100 to a position greater than the communication distance between the power transmission side narrow-area communication unit 170 and the power receiving side narrow-area communication unit 270, so the power transmission side narrow-area communication unit 170 can no longer receive power supply request signals from the vehicle CR. Therefore, instead of using the current flowing through the power transmission coil 112, or in conjunction with this method, the power supply may be determined to have ended by detecting that the power transmission side narrow-area communication unit 170 has stopped receiving power transmission request signals. With the power transmission device 100 configured in this way, the current sensor 310 of the end-type power transmission resonant circuit 110P can be omitted, and an increase in the number of components can be suppressed.

[0059] In step S320, when the transmitting control unit 180 determines that power supply by all transmitting resonant circuits 110 included in the transmittable region SC1 has been completed, it switches the transmitting device 100 from the energized state to the standby state. Specifically, when the detected value of the current sensor 310 in the end coil 112P falls below a predetermined threshold, the transmitting control unit 180 turns off the bidirectional switch circuit 117 to increase the input impedance Z1 and switches the current value flowing through the end coil 112P to a current value smaller than the current value that can be supplied to the receiving device 200. Similarly, when the detected value of the current sensor 322 in the other transmitting coils 112Q, 112R, and 112S falls below a predetermined threshold, the transmitting control unit 180 turns off the bidirectional switch circuit 117 and switches the current value flowing through the transmitting coils 112Q, 112R, and 112S to a current value smaller than the current value that can be supplied to the receiving device 200. As a result, the power transmission device 100 is switched from the energized state to the standby state.

[0060] In step S330, the power transmission control unit 180 uses a timer (not shown) to start timing from the time the power transmission device 100 is switched to standby mode, and waits for a predetermined standby time to elapse. The standby time can be arbitrarily set, for example, taking into account traffic conditions such as the frequency of vehicle travel in the power transmission area SC1. The standby time may be appropriately switched based on factors that are significant to the frequency of vehicle travel, such as daytime and nighttime, weekdays and holidays, and seasons. After the predetermined standby time has elapsed, the power transmission control unit 180 moves to step S340. In step S340, the power transmission control unit 180 stops driving the power transmission circuit 130, switches the power transmission device 100 to the stopped state, and terminates the process. Alternatively, it is also possible to terminate the process by detecting that wide-area communication between the vehicle CR's receiving-side wide-area communication unit 290 and the power transmission-side wide-area communication unit 190 has been interrupted.

[0061] As described above, the power transmission device 100 of this embodiment includes a power transmission resonant circuit 110 having a power transmission coil 112 and a power transmission resonant capacitor 116, a power transmission circuit 130 for supplying AC power to the power transmission resonant circuit 110, a receiving unit 172 as a power transmission request signal receiving unit for receiving a power transmission request signal transmitted from a power receiving device 200, and a switching unit 174 for switching the current value flowing through the power transmission coil 112. When the switching unit 174 receives a power transmission request signal from the power receiving device 200, it switches the current value flowing through the power transmission coil 112 to a current value that can supply power to the power receiving device 200. Therefore, it is possible to switch the power transmission device 100 to a power supply state more reliably than when using the change in magnetic flux generated in the power transmission coil. Accordingly, it is possible to suppress or prevent problems such as the power supply from the power transmission device 100 to the power receiving device 200 not starting when the power receiving coil 212 changes from a non-facing state to a facing state with respect to the power transmission coil 112.

[0062] According to the power transmission device 100 of this embodiment, the switching unit 174 switches the current value flowing through the power transmission coil 112 by switching the capacitance Ct of the unit by switching the bidirectional switch circuit 117 in the power transmission resonant capacitor 116 which uses a plurality of capacitors 116Pa, 116Pb and a bidirectional switch circuit 117. By using the bidirectional switch circuit 117, it is possible to change the size of the capacitance Ct of the power transmission resonant capacitor 116 while suppressing an increase in the size of the power transmission resonant capacitor 116h.

[0063] According to the power transmission device 100 of this embodiment, the receiving unit 172 can receive a power transmission request signal that includes ID information associated with at least one of the following: a vehicle equipped with a power receiving device 200, a power receiving coil 212 included in the power receiving device 200, or a user of the power receiving device 200. Therefore, by identifying the power receiving device 200 that requires power supply using the ID information and then supplying power, it is possible to prevent power supply to power receiving devices 200 that do not require power.

[0064] The power transmission device 100 of this embodiment includes a plurality of power transmission coils 112. The plurality of power transmission coils 112 are arranged to form a single linear power transmission area SC1 along the X-axis direction, which is the direction of travel of the vehicle CR. The receiving unit 172 is positioned near the end coil 112P, which is located at the end of the power transmission area SC1 among the plurality of power transmission coils 112. When the power receiving device 200 enters the power transmission area SC1 from outside the power transmission area SC1, it can reliably switch the power transmission coils 112 included in the power transmission area SC1 to a state where power can be supplied.

[0065] According to the power transmission device 100 of this embodiment, when a plurality of power transmission coils 112 form a power transmission area SC1, the receiving unit 172 is positioned only at the end coil 112P that the vehicle CR can first pass through in the power transmission area SC1 when the vehicle CR's movement path overlaps with the power transmission area SC1. After power supply to the end coil 112P is started, power supply to the receiving coil 212 from other power transmission coils 112 included in the power transmission area SC1 can be started without using narrow-range communication by utilizing the magnetic flux generated when the end coil 112P and the receiving coil 212 resonate.

[0066] According to the power transmission device 100 of this embodiment, the receiving unit 172 is capable of receiving narrow-range communication signals with a communication distance of 5 meters or less. Therefore, it is possible to improve the identifiability of a single vehicle CR to multiple moving vehicles and the electromagnetic compatibility (EMC) of the power transmission device 100, as well as to suppress unnecessary power consumption and the generation of unnecessary magnetic flux when the power receiving device 200 is not facing the transmission device.

[0067] In the power transmission device 100 of this embodiment, the switching unit 174 is provided integrally with the power transmission coil 112. Therefore, the power transmission device 100 can be made smaller compared to cases where the switching unit is connected to the power transmission circuit 130. Furthermore, if the power transmission device 100 has multiple power transmission coils 112, by providing the switching unit 174 integrally with each power transmission coil 112, the wiring from the power transmission circuit 130 to each power transmission coil 112 can be made common.

[0068] The power transmission device 100 of this embodiment further includes a power transmission-side wide-area communication unit 190 for receiving wide-area communication signals with a communication distance longer than 5 meters, and a power transmission-side control unit 180 capable of driving the power transmission circuit 130. The power transmission-side control unit 180 drives the power transmission circuit 130 when the power transmission-side wide-area communication unit 190 receives a wide-area communication signal. Therefore, by receiving a wide-area communication signal in advance before power supply and putting the power transmission device 100 into a standby state, the time required to switch to the power-on state when the power receiving device 200 is nearby can be shortened.

[0069] According to the power transmission device 100 of this embodiment, the power transmission control unit 180 drives the power transmission circuit 130 when it receives a wide-area communication signal and determines that the power receiving device 200 is at or below a predetermined preparation distance DT1 from the power transmission device 100. If the power receiving device 200 is farther away than the preparation distance DT1 and power supply is not required, the power transmission device 100 is stopped, thereby suppressing or preventing unnecessary power supply.

[0070] According to the power transmission device 100 of this embodiment, the power transmission side control unit 180 stops the power transmission circuit 130 and switches the power transmission device 100 to a stopped state if power is not supplied from the power transmission device 100 to the power receiving device 200 for a predetermined period of time. Therefore, it is possible to suppress unnecessary power consumption in the power transmission device 100 after power supply to the power receiving device 200 is completed.

[0071] According to the power transmission device 100 of this embodiment, a current sensor 310 is provided as a power transmission side detection circuit capable of detecting the current flowing through the power transmission coil 112. After power is supplied, if the value detected by the current sensor 310 falls below a predetermined threshold, the switching unit 174 switches the current value flowing through the power transmission coil 112 to a current value smaller than the current value that can be supplied to the power receiving device 200. Therefore, after power is supplied, it is possible to detect that the power receiving device 200 has entered a non-facing state with a simple configuration and switch the power transmission device 100 to a standby state.

[0072] B. Other embodiments: (B1) In the above embodiment, an example was described using a configuration in which multiple power transmission coils 112 are arranged in contact with each other. However, multiple power transmission coils 112 do not necessarily need to be in contact with each other, and may be spaced apart from each other. However, in order to ensure smooth power supply from the multiple power transmission coils 112 to the power receiving coil 212 while the vehicle CR is in motion, it is preferable that the power transmission coils 112 are in contact with each other, and if they are spaced apart, the spacing distance is preferably, for example, half the width of the power transmission coil 112 (or its radius if the power transmission coil 112 is circular) or less.

[0073] (B2) In the above embodiment, an example was shown in which a power transmission area SC2, configured similarly to the power transmission area SC1, is provided at a predetermined distance from the power transmission area SC1. In contrast, as shown in Figure 15, the power transmission area SC1 and the adjacent power transmission area SC2 may be provided in close proximity to each other. Figure 15 shows the distance DT3 between the power transmission area SC1 and the adjacent power transmission area SC2. When the distance DT3 is small enough that the power transmission area SC1 and the power transmission area SC2 can be considered to be arranged continuously, the power transmission device 100 of the power transmission area SC2 can detect the magnetic flux generated in the receiving coil 212 when supplying power to the power transmission area SC1. Therefore, with this form of power transmission device 100, the power transmission side narrow-area communication unit 170 of the power transmission area SC2 can be omitted.

[0074] (B3) In the above embodiment, an example was shown in which the vehicle CR is equipped with one power receiving resonant circuit 210. In contrast, as shown in Figure 16, the vehicle CR may be equipped with two or more power receiving resonant circuits 210. In the example in Figure 16, the vehicle CR is equipped with two power receiving resonant circuits 210F and 210B, and two power receiving coils 212F and 212B are powered by two power transmitting coils 112Q and 112R. In this case, it is preferable that the power receiving side narrow-range communication unit 270 is provided near the power receiving coil 212F which is located at the front of the vehicle CR in the direction of travel. By arranging the power receiving side narrow-range communication unit 270 at the front of the vehicle CR, narrow-range communication can be performed with the power transmitting device 100 early while the vehicle CR is in motion. Therefore, it is possible to suppress or prevent delays in the supply of power to the end coil 112P of the power transmission device 100 due to, for example, delays in narrow-area communication, and to suppress or prevent problems such as the power supply from the power transmission device 100 not being fast enough when the leading receiving coil 212F reaches the power transmission device 100.

[0075] (B4) In the above embodiment, an example was shown in which the power transmission side detection circuit is a current sensor 310. An example was also shown in which the change in current flowing through the power transmission coil is detected by the current sensor 322 of the variable control circuit 320. In contrast, since the coil voltage applied to the power transmission coil 112 also changes in the same way as the power transmission coil current, the sensors of the power transmission side detection circuit and the variable control circuit 320 may be voltage sensors, and they may detect the change in the coil voltage applied to the power transmission coil 112. Alternatively, the sensors of the power transmission side detection circuit and the variable control circuit 320 may use magnetic flux detection elements such as magnetic sensors or coils to detect the magnetic field (magnetic flux) in the vicinity of the power transmission coil 112.

[0076] (B5) In the above embodiment, an example was shown in which a power transmission resonant capacitor 116P is provided as a unit using multiple capacitors 116Pa, 116Pb and a bidirectional switch circuit 117. In contrast, a variable capacitor with variable capacitance may be used for the power transmission resonant capacitor 116. As the variable capacitor, a general variable capacitor whose capacitance Ct changes according to the control voltage Vc from the switching unit 174 or the variable control circuit 320 can be used. In this case, the capacitance Ct of the variable capacitor is set to a resonant capacitance C1 that satisfies the resonance condition so that the power transmission resonant circuit 110 is in a resonant state when facing each other, and is set to a capacitance smaller than the resonant capacitance C1 so that the power transmission resonant circuit 110 is out of a resonant state when not facing each other. Alternatively, a capacitor with constant capacitance can be used instead of the power transmission resonant capacitor 116P as a unit using multiple capacitors 116Pa, 116Pb and a bidirectional switch circuit 117 or a variable capacitor. In this case, the power transmission resonant circuit 110 is equipped with a switching element such as a semiconductor switch, and the variable control circuit 320 and the switching unit 174 can change the input impedance Z1 to the power transmission resonant circuit 110 by switching the semiconductor switch on and off. Specifically, when the semiconductor switch is turned on, the input impedance Z1 becomes approximately zero, and when the semiconductor switch is turned off, the input impedance Z1 changes to approximately infinity. With the power transmission device 100 configured in this way, the current value flowing through the power transmission resonant circuit 110 can be switched with a simple configuration.

[0077] (B6) In the above embodiment, the power transmission resonant circuits 110P, 110Q, 110R, and 110S are laid continuously in a straight line along the direction of travel of the vehicle CR (X-axis direction) on the vehicle travel path RS, and as a result, the multiple power transmission resonant circuits 110 form a single power transmission region SC1 arranged in a substantially straight line. In contrast, the multiple power transmission resonant circuits 110 are not limited to a straight line, and for example, in addition to a straight line along the direction of travel of the vehicle CR, they may also be laid continuously in a direction intersecting the direction of travel of the vehicle CR on the vehicle travel path RS, that is, along the width direction of the vehicle CR (Y-axis direction). By configuring in this way, a single power transmission region SC1 arranged in a substantially rectangular plane can be formed.

[0078] If the power transmission resonant circuit 110 is further laid along the width direction (Y-axis direction) of the vehicle CR to form a roughly rectangular planar power transmission area SC1, then "power transmission resonant circuit 110 located at the end of the power transmission area SC1" means the power transmission resonant circuit 110 located at the periphery of the rectangular planar power transmission area SC1. By providing the power transmission side narrow-range communication unit 170 on the end coil 112P located at the periphery of the planar power transmission area SC1, even if there are multiple directions in which the vehicle CR can enter the power transmission area SC1, such as when the vehicle CR changes lanes, changes direction of travel, or passes through an intersection, the power receiving device 200 can reliably switch the power transmission coil 112 included in the power transmission area SC1 to a state where it can supply power when it enters the power transmission area SC1.

[0079] (B7) In the above embodiment, the case of transmitting power from the transmitting coil 112 to the receiving coil 212 was described as an example. However, if the transmitting device 100 and the receiving device 200 are equipped with other resonant coils, such as relay coils, that can be used when supplying power from the transmitting device 100 to the receiving device 200, the configuration of the switching unit 174 and the like can be applied as a switching unit that switches the resonant state of the other resonant coils.

[0080] (B8) In the above embodiment, an example was shown in which a power transmission area SC2, configured similarly to the power transmission area SC1, is provided at a predetermined distance from the power transmission area SC1. Here, if the power transmission device 100 has a plurality of power transmission areas SC1, SC2, the power transmission request signal receiving unit provided in one of the power transmission areas SC1, SC2 and the power transmission request signal receiving unit provided in the other power transmission area SC2 adjacent to the one power transmission area SC1 may be spaced apart from each other. The distance at which they are spaced apart is preferably set to a distance greater than the communication distance of the narrow-area communication, for example. "Another power transmission area adjacent to one power transmission area" is not limited to cases where they are adjacent along the direction of travel of the vehicle CR shown in Figure 1, but also includes power transmission areas provided in the other adjacent lane when the vehicle travel path RS has a plurality of lanes traveling in the same direction, and may also include power transmission areas provided in the adjacent opposing lane. This type of power transmission device 100 can suppress or prevent interference in narrow-area communications between multiple power transmission areas SC1 and SC2.

[0081] This disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from its spirit. For example, the technical features in the embodiments corresponding to the technical features in each form described in the summary of the invention can be replaced or combined as appropriate in order to solve some or all of the above-described problems, or to achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate. [Explanation of Symbols]

[0082] 100...Power transmission device, 110...Power transmission resonant circuit, 112...Power transmission coil, 116...Power transmission capacitor, 130...Power transmission circuit, 172...Power receiving unit, 174...Switching unit, 200...Power receiving device

Claims

1. A power transmission device (100) for non-contact power supply to a movable power receiving device (200), A power transmission resonant circuit (110) having a power transmission coil (112) and a power transmission resonant capacitor (116), A power transmission circuit (130) for supplying AC power to the aforementioned power transmission resonant circuit, A power transmission request signal receiving unit (172) for receiving a power transmission request signal transmitted from the power receiving device, A switching unit (174) for switching the current value flowing through the power transmission coil, comprising: a switching unit that, upon receiving the power transmission request signal, changes the input impedance of the power transmission resonant circuit to switch the current value flowing through the power transmission coil to a current value that can supply power to the power receiving device; The power transmission request signal receiving unit is capable of receiving the power transmission request signal as a narrow-range communication signal with a communication distance of 5 meters or less. The system comprises multiple power transmission coils, The plurality of power transmission coils are arranged to form a single power transmission region (SC1, SC2) that is linear along one direction, or planar between the intersecting direction and the one direction. The power transmission request signal receiving unit is positioned near the end coil located at the end of the power transmission area among the plurality of power transmission coils, Power transmission equipment.

2. A power transmission device according to claim 1, The aforementioned power transmission resonant capacitor is a variable capacitor, The switching unit changes the input impedance by switching the capacitance of the variable capacitor. Power transmission equipment.

3. A power transmission device according to claim 1, The aforementioned power transmission resonant capacitor is a unit using multiple capacitors and switch circuits, The switching unit changes the input impedance by switching the switch circuit and thereby switching the capacitance of the unit. Power transmission equipment.

4. A power transmission device according to claim 1, The aforementioned power transmission resonant circuit includes a switch element, The switching unit changes the input impedance by switching the switching element to switch the power supply from the power transmission circuit to the power transmission resonant circuit on and off. Power transmission equipment.

5. A power transmission device according to any one of claims 1 to 4, The power transmission request signal receiving unit is capable of receiving the power transmission request signal which includes ID information associated with at least one of the vehicle on which the power receiving device is installed, the power receiving coil included in the power receiving device, and the user of the power receiving device. Power is supplied to the authorized power receiving device using the aforementioned ID information. Power transmission equipment.

6. A power transmission device according to any one of claims 1 to 5, The power transmission request signal receiving unit is positioned only near the end coil that the power receiving device first intersects when it moves along the movement path, when the movement path of the power receiving device overlaps with the power transmission area. Power transmission equipment.

7. A power transmission device according to any one of claims 1 to 6, Furthermore, the system includes multiple power transmission areas, The power transmission request signal receiving unit provided in one of the multiple power transmission areas and the power transmission request signal receiving unit provided in another power transmission area adjacent to the one power transmission area are spaced apart from each other. Power transmission equipment.

8. A power transmission device according to any one of claims 1 to 7, The switching unit is provided integrally with the power transmission coil. Power transmission equipment.

9. A power transmission device (100) for non-contact power supply to a movable power receiving device (200), A power transmission resonant circuit (110) having a power transmission coil (112) and a power transmission resonant capacitor (116), A power transmission circuit (130) for supplying AC power to the aforementioned power transmission resonant circuit, A power transmission request signal receiving unit (172) for receiving a power transmission request signal transmitted from the power receiving device, A switching unit (174) for switching the current value flowing through the power transmission coil, comprising: a switching unit that, upon receiving the power transmission request signal, changes the input impedance of the power transmission resonant circuit to switch the current value flowing through the power transmission coil to a current value that can supply power to the power receiving device; The power transmission request signal receiving unit is capable of receiving the power transmission request signal as a narrow-range communication signal with a communication distance of 5 meters or less. Furthermore, a wide-area communication unit (190) for receiving wide-area communication signals with a communication range longer than 5 meters, The system includes a power transmission side control unit (180) capable of driving the power transmission circuit, The power transmission control unit drives the power transmission circuit when the wide-area communication unit receives the wide-area communication signal. Power transmission equipment.

10. A power transmission device according to claim 9, The power transmission control unit, upon receiving the wide-area communication signal and determining that the power receiving device is at or below a predetermined preparation distance (DT1) from the power transmission device, drives the power transmission circuit. Power transmission equipment.

11. A power transmission device according to claim 9, The power transmission control unit shall shut down the power transmission circuit if power is not supplied from the power transmission device to the power receiving device for a predetermined period of time. Power transmission equipment.

12. A power transmission device according to any one of claims 1 to 11, Furthermore, the system includes a power transmission side detection circuit (310, 322) capable of detecting at least one of the following values: the current flowing through the power transmission coil, the voltage applied to the power transmission coil, and the magnetic field generated in the power transmission coil. The switching unit, after receiving the power transmission request signal and changing the current value flowing through the power transmission coil to the input impedance for switching to a current value that can supply power to the power receiving device, then, when the detection value of the power transmission side detection circuit falls below a predetermined threshold, changes the current value flowing through the power transmission coil to the input impedance for switching to a current value smaller than the current value that can supply power to the power receiving device. Power transmission equipment.

13. A power transmission device according to any one of claims 1 to 12, The switching unit, after receiving the power transmission request signal and changing the current value flowing through the power transmission coil to the input impedance for switching to a current value that can supply power to the power receiving device, then, when the power transmission request signal is no longer received, changes the current value flowing through the power transmission coil to the input impedance for switching to a current value smaller than the current value that can supply power to the power receiving device. Power transmission equipment.

14. A power transmission device (100) for non-contact power supply to a movable power receiving device (200), A power transmission resonant circuit (110) having a power transmission coil (112) and a power transmission resonant capacitor (116), A power transmission circuit (130) for supplying AC power to the aforementioned power transmission resonant circuit, A power transmission request signal receiving unit (172) for receiving a power transmission request signal transmitted from the power receiving device, A switching unit (174) for switching the current value flowing through the power transmission coil, comprising a switching unit that, upon receiving the power transmission request signal, switches the current value flowing through the power transmission coil to a current value that can supply power to the power receiving device, Furthermore, the system includes multiple power transmission coils, Multiple of the aforementioned power transmission coils are spaced apart from each other. Adjacent to the aforementioned power transmission resonant circuit is an adjacent power transmission resonant circuit (110Q) having an adjacent power transmission coil (112Q) and an adjacent power transmission resonant capacitor (116Q), When a current is detected flowing through the adjacent power transmission coil, the adjacent switching unit (320) changes the input impedance of the adjacent power transmission resonant circuit to switch the current value flowing through the adjacent power transmission coil to a current value that can supply power to the power receiving device, A power transmission device equipped with the following features.

15. A power transmission device (100) for non-contact power supply to a movable power receiving device (200), A power transmission resonant circuit (110) having a power transmission coil (112) and a power transmission resonant capacitor (116), A power transmission circuit (130) for supplying AC power to the aforementioned power transmission resonant circuit, A power transmission request signal receiving unit (172) for receiving a power transmission request signal transmitted from the power receiving device, A switching unit (174) for switching the current value flowing through the power transmission coil, comprising: a switching unit that, upon receiving the power transmission request signal, changes the input impedance of the power transmission resonant circuit to switch the current value flowing through the power transmission coil to a current value that can supply power to the power receiving device; The power transmission request signal receiving unit is capable of receiving the power transmission request signal as a narrow-range communication signal with a communication distance of 5 meters or less. Adjacent to the aforementioned power transmission resonant circuit is an adjacent power transmission resonant circuit (110Q) having an adjacent power transmission coil (112Q) and an adjacent power transmission resonant capacitor (116Q), When a current is detected flowing through the adjacent power transmission coil, the adjacent switching unit (320) changes the input impedance of the adjacent power transmission resonant circuit to switch the current value flowing through the adjacent power transmission coil to a current value that can supply power to the power receiving device, A power transmission device equipped with the following features.

16. A power transmission device according to claim 14 or claim 15, The system comprises multiple power transmission coils, Multiple of the aforementioned power transmission coils are arranged in a straight line along one direction. The power transmission request signal receiving unit is positioned near the end coil located at the end of the plurality of power transmission coils, Power transmission equipment.

17. A contactless power supply system, A power transmission device according to any one of claims 1 to 16, The power receiving device comprises a power transmission request signal transmitting unit (270) for transmitting the power transmission request signal, Contactless power supply system.

18. A power transmission method for non-contact power supply to a movable power receiving device (200), When a power transmission request signal is received from the power receiving device as a narrow-range communication signal with a communication distance of 5 meters or less, the current value flowing through the power transmission coil (112) included in the power transmission resonant circuit (110) is switched to a current value that can supply power to the power receiving device by changing the input impedance of the power transmission resonant circuit. Multiple power transmission coils are arranged, The plurality of power transmission coils are arranged to form a single power transmission region (SC1, SC2) that is linear along one direction, or planar between the intersecting direction and the one direction. The power transmission request signal is received by a power transmission request signal receiving unit located near the end coil of the plurality of power transmission coils that is located at the end of the power transmission area. Method of power transmission.

19. A power transmission method for non-contact power supply to a movable power receiving device (200), When a power transmission request signal is received from the power receiving device as a narrow-range communication signal with a communication distance of 5 meters or less, the current value flowing through the power transmission coil (112) included in the power transmission resonant circuit (110) is switched to a current value that can supply power to the power receiving device by changing the input impedance of the power transmission resonant circuit. The power transmission side control unit (180), which is capable of driving a power transmission circuit for supplying AC power to the power transmission resonant circuit, drives the power transmission circuit when the wide-area communication unit (190), which is for receiving wide-area communication signals with a communication distance longer than 5 meters, receives the wide-area communication signal. Method of power transmission.

20. A power transmission method for non-contact power supply to a movable power receiving device (200), When a power transmission request signal is received from the power receiving device, the current value flowing through the power transmission coil (112) included in the power transmission resonant circuit (110) is switched to a current value that can supply power to the power receiving device. Multiple power transmission coils are arranged spaced apart from each other. In an adjacent power transmission resonant circuit (110Q) adjacent to the aforementioned power transmission resonant circuit and having an adjacent power transmission coil (112Q) and an adjacent power transmission resonant capacitor (116Q), when a current flowing through the adjacent power transmission coil is detected, the input impedance of the adjacent power transmission resonant circuit is changed to switch the current value flowing through the adjacent power transmission coil to a current value that can supply power to the power receiving device. Method of power transmission.

21. A power transmission method for non-contact power supply to a movable power receiving device (200), When a power transmission request signal is received from the power receiving device as a narrow-range communication signal with a communication distance of 5 meters or less, the current value flowing through the power transmission coil (112) included in the power transmission resonant circuit (110) is switched to a current value that can supply power to the power receiving device by changing the input impedance of the power transmission resonant circuit. In an adjacent power transmission resonant circuit (110Q) adjacent to the aforementioned power transmission resonant circuit and having an adjacent power transmission coil (112Q) and an adjacent power transmission resonant capacitor (116Q), when a current flowing through the adjacent power transmission coil is detected, the input impedance of the adjacent power transmission resonant circuit is changed to switch the current value flowing through the adjacent power transmission coil to a current value that can supply power to the power receiving device. Method of power transmission.

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