Contactless power transmission system, power transmission device and mobile body

Abstract

To provide a non-contact power transmission system capable of performing proper power transmission to a plurality of different mobiles, a power transmission apparatus and a mobile.SOLUTION: A non-contact power transmission system 1 comprises a power transmission section 8, a transmission power conversion section 7, and a transmission-side control device 9. The power transmission section 8 includes a primary-side coil 8a which sends out AC power to be transmitted to a power reception apparatus 4 in a non-contact manner. The transmission power conversion section 7 includes a plurality of transistors 7a and 7b connected to the primary-side coil 8a. The transmission power conversion section 7 converts DC power, which is supplied from a power source section 6, into AC power. The transmission-side control device 9 sets initial transmission power in the start of power transmission by the power transmission section 8 less than predetermined power. The transmission-side control device 9 changes transmission power into an increase trend toward the predetermined power in accordance with the lapse of time from the start of power transmission by the power transmission section 8.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a contactless power transfer system, a power transmitting device, and a mobile object. [Background technology]

[0002] In recent years, research and development has been conducted into charging vehicles equipped with secondary batteries that contribute to energy efficiency, in order to ensure that more people have access to affordable, reliable, sustainable and advanced energy. Conventionally, in a contactless power transmission system that supplies power from a power transmitting side to a power receiving side through contactless power transmission, a system is known in which the power transmitting side identifies the power receiving side and transmits power according to the power required by the power receiving side based on information transmitted from the power receiving side to the power transmitting side (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-393 Summary of the Invention [Problem to be solved by the invention]

[0004] In technology related to charging and supplying power to vehicles equipped with secondary batteries, it is desirable to quickly and accurately identify each of multiple moving vehicles and to transmit appropriate power according to their required power. For example, in the case of a moving vehicle receiving power from a power transmitting coil installed on the road, it is desirable to establish communication between the power transmitting side and the power receiving side and complete power transmission according to the required power within an extremely short time, such as several tens of milliseconds. Furthermore, it is desirable to transmit power to each of the multiple moving vehicles at appropriate timing, including simultaneously, even in a mixed traffic environment where there are multiple moving vehicles with different required power, and where inter-vehicle distances are reduced and vehicles cut in. However, in the above-described conventional systems, each of the vehicle and the ground power feeding device requires two different dedicated wireless communication devices, one for wide-area wireless communication and the other for short-range wireless communication, in addition to a power receiving device or a power transmitting device, which results in a problem of a complicated system configuration. Furthermore, for example, in the short-range wireless communication for vehicle identification immediately before the start of power feeding, if communication is unstable or not established within an extremely short time, there is a risk of an abnormality such as failure to transmit power or excessive power feeding.

[0005] An object of the present invention is to provide a contactless power transfer system, a power transmitting device, and a mobile body that can properly transfer power to a plurality of different mobile bodies, thereby contributing to energy efficiency. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the above object, the present invention employs the following aspects. (1): A contactless power transmission system according to one aspect of the present invention (e.g., contactless power transmission system 1 in the embodiment) includes a power receiving side coil (e.g., secondary side coil 15a in the embodiment), a power receiving side communication device (e.g., on-board communication device 5 in the embodiment), and a power receiving side control device (e.g., power receiving side control device 17 in the embodiment) mounted on a moving body (e.g., vehicle V in the embodiment), and a power transmitting device (e.g., power transmitting device 2 in the embodiment) having at least one power transmitting side coil (e.g., primary side coil 8a in the embodiment), a power transmitting side communication device (e.g., communication system M in the embodiment), and a power transmitting side control device (e.g., power transmitting side control device 9 in the embodiment) arranged on a moving path (e.g., travel path R in the embodiment) of the moving body, and the power receiving side communication device and the power transmitting side communication device are connected to each other. the power receiving side communication device transmits and receives first information through a first wireless communication before the degree of coupling between the power receiving side coil and the power transmitting side coil reaches a predetermined degree or higher, the power receiving side coil transmits second information to the power transmitting side coil through a second communication using an induced voltage of magnetic field coupling after the first communication between the power receiving side communication device and the power transmitting side communication device or when the power receiving side coil and the power transmitting side coil are within a predetermined distance from each other, the power transmitting side coil transmits power to the power receiving side coil in a contactless manner after the second communication with the power receiving side coil, and the power receiving side control device and the power transmitting side control device control the communication of the first information and the second information and control the contactless power transmission between the power receiving side coil and the power transmitting side coil based on the first information and the second information.

[0007] (2): In the contactless power transmission system described in (1) above, the first information transmitted from the power receiving side communication device to the power transmitting side communication device may include at least information related to power transmission, the first information transmitted from the power transmitting side communication device to the power receiving side communication device may include at least key information, and the second information may include at least the key information.

[0008] (3): In the contactless power transfer system described in (2) above, the power transmitting device includes at least one power transmitting side power conversion unit (e.g., power supply unit 6 in the embodiment) connected to each of the at least one power transmitting side coil and independently converting power supplied from a power source (e.g., power supply unit 6 in the embodiment), and the power transmitting side control device may independently control contactless power transfer by each of the at least one power transmitting side coil in accordance with information related to the power transfer that corresponds to the key information received by each of the at least one power transmitting side coil from the power receiving side coil based on a combination of the key information and information related to the power transfer.

[0009] (4): In the contactless power transmission system described in (3) above, after transmitting the key information from the power transmitting side communication device to the power receiving side communication device, the power transmitting side control device may transition the power transmitting side power conversion unit from a stopped state to a state waiting to receive the second information, and after the power transmitting side coil has completed matching of the key information received from the power receiving side coil, transition the power transmitting side power conversion unit from the waiting to receive state to a search state in which a voltage pulse is output to estimate the coupling degree, transition the power transmitting side power conversion unit to a power transmission control state if the coupling degree reaches or exceeds a predetermined threshold degree in the search state, and transition the power transmitting side power conversion unit to the waiting to receive state if the coupling degree does not reach or exceed the predetermined threshold degree in the search state.

[0010] (5): The contactless power transmission system described in (4) above includes a receiving power conversion unit (e.g., receiving power conversion unit 16 in the embodiment) mounted on the mobile body and connected to the receiving coil, and the receiving control device may transition the receiving power conversion unit from a short-circuit state of the receiving coil to a state of transmitting the second information after the receiving communication device receives the key information from the transmitting communication device, transition the receiving power conversion unit from the transmission state to a power reception standby state after transmitting the second information, transition the receiving power conversion unit to a power reception control state if the received power reaches or exceeds a predetermined power within a predetermined time in the receiving standby state, and transition the receiving power conversion unit to the transmission state if the received power does not reach or exceed the predetermined power within the predetermined time in the receiving standby state.

[0011] (6) A power transmission device according to one aspect of the present invention (e.g., the power transmission device 2 in the embodiment) is arranged on a path (e.g., a travel path R in the embodiment) of a moving body (e.g., a vehicle V in the embodiment), and includes at least one power transmission side coil (e.g., the primary side coil 8a in the embodiment) that transmits power in a contactless manner to a power reception side coil (e.g., the secondary side coil 15a in the embodiment) mounted on the moving body, and a power transmission side coil (e.g., the primary side coil 8a in the embodiment) that transmits power to the moving body before the degree of coupling between the power transmission side coil and the power reception side coil reaches a predetermined degree or more. The power transmission side communication device (e.g., communication system M in the embodiment) transmits and receives first information through a first wireless communication with an on-board power reception side communication device (e.g., on-board communication device 5 in the embodiment), and a power transmission side control device (e.g., power transmission side control device 9 in the embodiment) controls contactless power transmission between the power receiving side coil and the power transmission side coil based on second information received by the power transmission side coil through a second communication using an induced voltage of magnetic field coupling between the power receiving side coil and the power transmission side coil, and the first information.

[0012] (7): The power transmitting device described in (6) above includes at least one power transmitting side power conversion unit (e.g., power transmitting power conversion unit 7 in the embodiment) connected to each of at least one of the power transmitting side coils and independently converting the power supplied from a power source, wherein the first information received by the power transmitting side communication device from the power receiving side communication device includes at least information related to power transmission, the first information transmitted by the power transmitting side communication device to the power receiving side communication device includes at least key information, and the second information includes at least the key information, and the power transmitting side control device may independently control contactless power transmission by each of at least one of the power transmitting side coils based on a combination of the key information and the information related to the power transmission, in accordance with the information related to the power transmission associated with the key information received by each of the at least one of the power transmitting side coils from the power receiving side coil.

[0013] (8): In the power transmission device described in (7) above, after transmitting the key information from the power transmission side communication device to the power receiving side communication device, the power transmission side control device may transition the power transmission side power conversion unit from a stopped state to a state waiting to receive the second information, and after the power transmission side coil has completed matching of the key information received from the power receiving side coil, transition the power transmission side power conversion unit from the waiting to receive state to a search state in which a voltage pulse is output to estimate the coupling degree, transition the power transmission side power conversion unit to a power transmission control state if the coupling degree reaches or exceeds a predetermined threshold degree in the search state, and transition the power transmission side power conversion unit to the waiting to receive state if the coupling degree does not reach or exceed the predetermined threshold degree in the search state.

[0014] (9): A moving body (e.g., vehicle V in the embodiments) according to one aspect of the present invention includes a power receiving coil (e.g., secondary coil 15a in the embodiments) that receives power transmitted contactlessly from a power transmitting coil (e.g., primary coil 8a in the embodiments), a power receiving communication device (e.g., in-vehicle communication device 5 in the embodiments) that transmits and receives first information through a first wireless communication with a power transmitting communication device (e.g., communication system M in the embodiments) provided in a power transmitting device (e.g., power transmitting device 2 in the embodiments) before the degree of coupling between the power transmitting coil and the power receiving coil reaches a predetermined degree or higher, and a power receiving control device (e.g., power receiving control device 17 in the embodiments) that transmits second information to the power transmitting coil through a second communication using an induced voltage of magnetic field coupling between the power receiving coil and the power transmitting coil.

[0015] (10): The mobile body described in (9) above includes a power receiving side power conversion unit (for example, the power receiving power conversion unit 16 in the embodiment) connected to the power receiving side coil, the first information transmitted by the power receiving side communication device to the power transmitting side communication device includes at least information related to power transmission, the first information received by the power receiving side communication device from the power transmitting side communication device includes at least key information, the second information includes at least the key information, and the power receiving side control device is configured to and then transitioning the receiving-side power conversion unit from a short-circuit state of the receiving-side coil to a state of transmitting the second information, and after transmitting the second information, transitioning the receiving-side power conversion unit from the transmission state to a state of standby for receiving power, and transitioning the receiving-side power conversion unit to a power reception control state if the received power reaches or exceeds a predetermined power within a predetermined time in the power reception standby state, and transitioning the receiving-side power conversion unit to the transmission state if the received power does not reach or exceed the predetermined power within the predetermined time in the power reception standby state. [Effects of the Invention]

[0016] According to (1) above, by providing a power receiving side communication device and a power transmitting side communication device that communicate first information (first communication), and a power receiving side coil and a power transmitting side coil that communicate second information (second communication) and transmit power contactlessly, it is possible to eliminate the need for a special communication device for communicating the second information (second communication), and to prevent the system configuration from becoming complicated.

[0017] In the case of (2) above, for example, communication of the first information having a large capacity can be performed by the power receiving side communication device and the power transmitting side communication device, and communication of the second information having a small capacity required at least for identifying the moving body can be performed by the power receiving side coil and the power transmitting side coil. Since contactless power transmission is performed by the power receiving side coil and the power transmitting side coil that have been paired by communication and collation of key information, appropriate power transmission control and power reception control can be performed with high reliability.

[0018] In the case of (3) above, for example, even if multiple combinations of power transmitting coils and power transmitting power converters are connected to a common power source, the communication and verification of key information and power transmission are controlled independently for each combination, which allows power transmission at an appropriate timing and with an appropriate power level, even in an environment where multiple mobile objects with different power requirements exist.

[0019] In the case of (4) above, by providing a search state for the transmitting side power conversion unit, when the degree of coupling between the paired receiving side coil and transmitting side coil reaches or exceeds a predetermined threshold degree suitable for power transmission, power transmission control can be executed appropriately.

[0020] In the case of (5) above, by providing a short-circuit state for the power receiving side power conversion unit, unnecessary communication from the power receiving side coil to the power transmitting side coil can be prevented. By providing a power reception standby state for the power receiving side power conversion unit, appropriate voltage detection can be performed according to the searching state of the power transmitting side power conversion unit. Furthermore, when the received power increases appropriately as the degree of coupling between the paired power receiving side coil and power transmitting side coil increases, appropriate power receiving control can be performed.

[0021] According to (6) above, by providing a power transmission side communication device that communicates the first information (first communication) and a power transmission side coil that communicates the second information (second communication) and transmits power contactlessly, it is possible to eliminate the need for a special communication device for communicating the second information, for example, and to prevent the system configuration from becoming complicated.

[0022] In the case of (7) above, for example, the communication of the first information, which has a large capacity, can be performed by the power transmitting communication device, and the communication of the second information, which has a small capacity and is required only for identifying at least the moving object, can be performed by the power transmitting coil. Since the power receiving coil and the power transmitting coil, which are paired by the communication and collation of the key information, perform contactless power transmission, it is possible to reliably execute appropriate power transmission control. Even when multiple combinations of power transmitting coils and power transmitting power converters are connected to a common power source, the communication and verification of key information and the power transmission are controlled independently for each combination, which allows power transmission at the appropriate timing and with the appropriate power even in an environment where, for example, there are multiple mobile objects with different power requirements.

[0023] In the case of (8) above, by providing a search state for the transmitting side power conversion unit, when the degree of coupling between the paired receiving side coil and transmitting side coil reaches or exceeds a predetermined threshold degree suitable for power transmission, power transmission control can be executed appropriately.

[0024] According to (9) above, by providing a power receiving side communication device that communicates the first information (first communication) and a power receiving side coil that communicates the second information (second communication) and transmits power contactlessly, it is possible to eliminate the need for a special communication device for communicating the second information, for example, and to prevent the system configuration from becoming complicated.

[0025] In the case of (10) above, for example, the communication of the first information, which has a large capacity, can be performed by the power receiving communication device, and the communication of the second information, which has a small capacity and is required only for identifying at least the moving body, can be performed by the power receiving coil. Since the power receiving coil and the power transmitting coil, which are paired by the communication and collation of the key information, perform contactless power transmission, it is possible to reliably perform appropriate power receiving control. By providing a short-circuit state for the receiving-side power conversion unit, unnecessary communication from the receiving-side coil to the transmitting-side coil can be prevented. By providing a power reception standby state for the receiving-side power conversion unit, appropriate voltage detection can be performed in accordance with the searching state of the transmitting-side power conversion unit. Furthermore, when the received power increases appropriately as the degree of coupling between the paired receiving-side coil and transmitting-side coil increases, appropriate power reception control can be performed. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a diagram showing an example of the configuration of a contactless power transmission system according to an embodiment of the present invention; [Figure 2] 1 is a diagram showing an example of the configuration of a contactless power transmission system according to an embodiment of the present invention; [Figure 3] FIG. 2 is a diagram showing details of the configuration of a contactless power transmission system according to an embodiment of the present invention. [Figure 4] 1 is a diagram showing the configuration of a power transmitting unit and a power receiving unit of a contactless power transfer system according to an embodiment of the present invention. [Figure 5] FIG. 2 is a diagram showing a T-type equivalent circuit in the contactless power transfer system according to the embodiment of the present invention. [Figure 6] 3A and 3B are diagrams showing an example of communication and power transmission operations accompanying movement of a moving body (vehicle) in an embodiment of the present invention. [Figure 7] FIG. 2 is a graph showing an example of the correspondence between power and efficiency according to horizontal distance (the relative movement amount between the primary coil and the secondary coil in a direction parallel to the road surface) in the contactless power transfer system according to the embodiment of the present invention. [Figure 8] 4 is a flowchart showing a power receiving side process of the contactless power transmission system according to the embodiment of the present invention. [Figure 9] 4 is a flowchart showing a power transmission side process of the contactless power transmission system according to the embodiment of the present invention. [Figure 10] FIG. 10 is a diagram showing an example of the correspondence between the receiving-side drive signal, the receiving-side voltage, the transmitting-side voltage, the receiving-side current, and the coupling coefficient during communication between the primary coil and the secondary coil prior to the start of power transmission in the contactless power transmission system according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, a contactless power transfer system according to an embodiment of the present invention will be described with reference to the accompanying drawings. 1 and 2 are diagrams illustrating an example of the configuration of a contactless power transfer system 1 according to an embodiment. A contactless power transfer system 1 according to the embodiment supplies power to a mobile body from outside the mobile body (such as a travel path) by contactless power transfer. The mobile body is, for example, a vehicle V. The vehicle V is, for example, an electrically powered vehicle such as an electric vehicle, a hybrid vehicle, or a fuel cell vehicle. The outside of the mobile body (such as a travel path) is, for example, a travel path R of the vehicle V.

[0028] (contactless power transmission system) As shown in Figures 1 and 2, the contactless power transfer system 1 of the embodiment includes, for example, a power transmission device 2 installed on a driving path R of a vehicle V, a drive control device 3, a power receiving device 4, and an on-board communication device 5 mounted on the vehicle V. The contactless power transfer system 1 of the embodiment may include only components external to the vehicle V (for example, the power transmission device 2), or may perform contactless power transfer by combining components mounted on the vehicle V (for example, the drive control device 3, the power receiving device 4, and the on-board communication device 5) with the contactless power transfer system 1 external to the vehicle V. The contactless power transfer system 1 of the embodiment may include only components mounted on the vehicle V (for example, the drive control device 3, the power receiving device 4, and the on-board communication device 5), or may perform contactless power transfer by combining components external to the vehicle V (for example, the power transmission device 2) with the contactless power transfer system 1 mounted on the vehicle V.

[0029] The power transmitting device 2 includes, for example, a communication system M constituting a power transmitting side communication device, a power supply unit 6, at least one set (for example, multiple sets) of a power transmitting power conversion unit 7 and a power transmitting unit 8, and a power transmitting side control device 9. The communication system M communicates wirelessly with an in-vehicle communication device 5 that constitutes a power receiving side communication device mounted on a vehicle V. The communication system M constitutes at least a part of a system for electronically collecting tolls, such as an ETC (Electronic Toll Collection System) on toll roads, and a system for exchanging road traffic information and various types of information for driving assistance. The communication system M includes at least one roadside communication device Ma that wirelessly communicates with an in-vehicle communication device 5 of a vehicle V by road-to-vehicle communication, and a communication control device Mb. Each of the at least one roadside communication device Ma and the communication control device Mb are connected via, for example, a wired or wireless communication network. The communication network includes, for example, the Internet, a mobile communication network, a LAN (Local Area Network), a WAN (Wide Area Network), etc.

[0030] The roadside communication device Ma is arranged, for example, a predetermined distance upstream of a coupling section (communication sections CS1, CS2 and power transmission section TS) described later on the roadway R of the vehicle V. The roadside communication device Ma is equipped with various communication devices such as an antenna for wireless communication. The communication control device Mb controls the operation of all roadside communication devices Ma that are associated with it in advance. The communication control device Mb is a software function unit that functions when a processor such as a CPU (Central Processing Unit) executes a predetermined program. The software function unit is an ECU that includes a processor such as a CPU, a ROM (Read Only Memory) that stores programs, a RAM (Random Access Memory) that temporarily stores data, and electronic circuits such as a timer. At least a part of the communication control device Mb may be an integrated circuit such as an LSI (Large Scale Integration).

[0031] The communication system M and the in-vehicle communication device 5 correspond to, for example, a primary authentication device and a secondary authentication device, and exchange authentication information that is exclusively assigned to at least each vehicle V. The communication system M and the in-vehicle communication device 5 attempt to exchange first information, for example, by wireless communication between the roadside communication device Ma and the in-vehicle communication device 5 of a nearby vehicle V at a predetermined period or the like.

[0032] For example, the first information transmitted from the in-vehicle communication device 5 to the communication system M includes at least information related to power transmission. The information related to power transmission includes, for example, information on a power transmission request such as the required power and required frequency for power transmission from the power transmitting device 2 to the vehicle V, and information necessary for billing and settlement for the power transmission. The information necessary for billing and settlement is information specific to the vehicle V, such as the presence and identifier of an IC card or an in-vehicle transponder for toll collection.

[0033] For example, the first information transmitted from the communication system M to the in-vehicle communication device 5 includes at least key information and information related to the installation of the power transmission device 2. The key information is, for example, information that is generated while being updated at a predetermined period so as to be different for each authorized vehicle V (i.e., vehicle V permitted to perform power transmission) passing through a predetermined power transmission section TS described later. The key information is information required for the power transmission device 2 to authenticate the power receiving device 4 of the vehicle V and to start power transmission. The information related to the installation of the power transmission device 2 is, for example, information such as the installation intervals of multiple power transmission units 8 described later and the distance from the roadside communication device Ma.

[0034] For example, when the communication system M acquires information necessary for charging and settling for power transmission from the in-vehicle communication device 5, it checks whether electronic payment is possible. If the communication system M checks that electronic payment is possible, it transmits permission information indicating permission for power transmission and key information necessary to start power transmission to the in-vehicle communication device 5. When the communication system M transmits the key information to the in-vehicle communication device 5, it transmits information combining the same key information and information related to power transmission received from the in-vehicle communication device 5 to the power transmitting side control device 9 described below.

[0035] The power supply unit 6 is connected to, for example, a plurality of transmission power conversion units 7. The power supply unit 6 includes, for example, an AC power supply such as a commercial power supply, an AC-DC converter that converts the AC power into DC power, and a power smoothing capacitor. The power supply unit 6 converts the AC power supplied from the AC power supply into DC power using the AC-DC converter.

[0036] Fig. 3 is a diagram showing the detailed configuration of the contactless power transfer system 1 according to the embodiment. Fig. 4 is a diagram showing the configurations of the power transmitting unit 8 and the power receiving unit 15 of the contactless power transfer system 1 according to the embodiment. As shown in FIG. 3, the transmission power conversion unit 7 includes, for example, an inverter that converts DC power into AC power. The inverter of the transmission power conversion unit 7 includes, for example, a first bridge circuit formed by a plurality of switching elements and rectifying elements bridge-connected in two phases, and a capacitor for resonance adjustment. Each switching element is, for example, a transistor such as a SiC (Silicon Carbide) MOSFET (Metal Oxide Semiconductor Field Effect Transistor). The plurality of switching elements are high-side arm and low-side arm transistors 7a, 7b that form a pair in each phase. The rectifying element is, for example, a freewheeling diode connected in parallel to each of the transistors 7a, 7b. A voltage smoothing capacitor 7c is connected in parallel to the first bridge circuit. The transmission power conversion unit 7 includes, for example, a sensor such as a current sensor that detects the current of the DC power.

[0037] The power transmitting unit 8 is connected to the AC terminals of the first bridge circuit of the power transmitting power converter 7. The power transmitting unit 8 transmits power by changing a high-frequency magnetic field, for example, through magnetic field coupling such as magnetic resonance or electromagnetic induction. As shown in FIGS. 3 and 4, the power transmitting unit 8 includes a resonant circuit formed by, for example, a primary coil 8a, a primary resistor 8b, and a primary capacitor 8c connected in series. The power transmitting unit 8 includes sensors such as a current sensor 9a that detects a current (power transmitting side current) It flowing through the resonant circuit and a voltage sensor 9b that detects a voltage (power transmitting side voltage) Vt of the resonant circuit.

[0038] The power transmitting side control device 9 comprehensively controls the power transmitting devices 2. The power transmitting side control device 9 is a software function unit that functions when a processor such as a CPU (Central Processing Unit) executes a predetermined program. The software function unit is an ECU that includes a processor such as a CPU, a ROM (Read Only Memory) that stores programs, a RAM (Random Access Memory) that temporarily stores data, and electronic circuits such as a timer. At least a part of the power transmitting side control device 9 may be an integrated circuit such as an LSI (Large Scale Integration).

[0039] For example, in power transmission control during power transmission between the power transmitting device 2 and the power receiving device 4, the power transmitting side control device 9 independently controls the current switching operation of each of the multiple power transmitting power conversion units 7. For example, the power transmitting side control device 9 independently controls each of the multiple power transmitting power conversion units 7 so that multiple sets of power transmitting power conversion units 7 and power transmitting units 8 individually transmit power to the power receiving devices 4 of different vehicles V at appropriate timings including simultaneously.

[0040] The transmission side control device 9 generates, for example, a control signal for each of the multiple transmission power conversion units 7 indicating the timing for driving each switching element on (conducting) and off (cutting), and also generates a gate signal for actually driving each switching element on and off based on the control signal. For example, the power transmission side control device 9 transmits power to the power receiving device 4 of the vehicle V corresponding to each power transmission power conversion unit 7 and each power transmission unit 8 by controlling the on (conduction) and off (cutoff) switching of each switching element for each of the multiple power transmission power conversion units 7 in accordance with information on a predetermined drive frequency or a required frequency received from the power receiving device 4.

[0041] For example, prior to the start of power transmission between the power transmission device 2 and the power receiving device 4, the power transmission side control device 9 controls communication between the power transmission device 2 and the power receiving device 4 via the primary side coil 8a and the secondary side coil 15a. For example, when the power transmitting side control device 9 receives information that is a combination of key information and information related to power transmission from the communication system M, it recognizes that the same key information has been transmitted to the in-vehicle communication device 5 of the vehicle V, and transitions the power transmitting device 2 from a stopped state to a reception standby state. The stopped state of the power transmitting device 2 is a state in which the switching operation of each of the multiple power transmitting power conversion units 7 is stopped, for example, by maintaining each switching element of each of the multiple power transmitting power conversion units 7 in an off (blocked) state. The reception standby state of the power transmitting device 2 is a state in which the transmission of information from the power receiving device 4 of the vehicle V is detected. The reception standby state of the power transmitting device 2 is, for example, a short-circuit state of each of the power transmitting power conversion units 7.

[0042] When each transmitting power converter 7 is short-circuited, the transmitting-side control device 9 short-circuits the primary coil 8a by setting the low-side arm transistor 7b of each phase to on. As a result, when the primary power transmitting device 2 is viewed from the secondary power receiving device 4, the impedance of the primary side becomes very large. However, when a magnetic field is generated by the secondary coil 15a of the power receiving device 4 during PING transmission (described later), communication from the power receiving device 4 is detected by the voltage induced in the primary coil 8a of the power transmitting device 2. The transmitting-side control device 9 acquires information superimposed on the PING signal by demodulating the voltage detected during PING transmission.

[0043] For example, when the power transmitting side control device 9 receives key information via a PING signal transmitted from the secondary coil 15a of the power receiving device 4 to an appropriate primary coil 8a of the power transmitting device 2, the power transmitting side control device 9 verifies the key information based on a combination of the key information and information related to power transmission previously received from the communication system M. If the key information received from the communication system M and the power receiving device 4 matches, the power transmitting side control device 9 transitions the transmitting power conversion unit 7 corresponding to the primary coil 8a that received the key information from a reception standby state to a search state (search mode). In the search state of the transmitting power conversion unit 7, the power transmitting side control device 9 estimates a coupling coefficient k between the primary coil 8a and the secondary coil 15a based on current detection in the power transmitting unit 8, while outputting a voltage pulse to the primary coil 8a by a current switching operation in the transmitting power conversion unit 7, for example.

[0044] In the search state of each transmission power conversion unit 7, the transmission side control device 9 acquires the mutual inductance Lm and coupling coefficient k between the primary coil 8a and the secondary coil 15a based on the detection values ​​output from the current sensor 9a and voltage sensor 9b of the transmission unit 8. FIG. 5 is a diagram showing a T-type equivalent circuit in the contactless power transfer system 1 of the embodiment. As shown in FIG. 5, the T-type equivalent circuit of the contactless power transfer system 1 is described by, for example, the voltage Vt of the AC voltage source 21, the capacitance Ct, internal resistance Rt, self-inductance Lt, and current It of the power transmitting unit 8, the mutual inductance Lm, the capacitance Cr, internal resistance Rr, self-inductance Lr, and current Ir of the power receiving unit 15, and the voltage Vr and load resistance RL of the load resistor 22. The load resistance 22 corresponds to, for example, a receiving power conversion unit 16 described below and a load resistance A connected between the DC terminals (positive and negative poles) of the receiving power conversion unit 16. The load resistance A is, for example, the drive control device 3.

[0045] As shown in the voltage equation in the following formula (1), the current It of the power transmitting unit 8, and the current Ir and voltage Vr of the power receiving unit 15 are described by the power transmission frequency ω0, the mutual inductance Lm, the respective resistance values ​​Rt, Rr, RL, and the voltage Vt of the power transmitting unit 8.

[0046]

number

[0047] For example, a state in which power transmission is efficient is a state in which the voltage Vt of the power transmitting unit 8 and the voltage Vr of the power receiving unit 15 are the same, but since the voltage Vr of the power receiving unit 15 is obtained by PING communication, the voltage Vt of the power transmitting unit 8 and the voltage Vr of the power receiving unit 15 are described by a predetermined coefficient a, as shown in the following equation (2).

[0048]

number

[0049] As shown in the following equation (3), based on the above equations (1) and (2), the load resistance value RL is described by the power transmission frequency ω0, the mutual inductance Lm, and the respective internal resistance values ​​Rt and Rr.

[0050]

number

[0051] Based on the above formulas (1) and (3), the mutual inductance Lm is obtained from the known internal resistance values ​​Rt, Rr, power transmission frequency ω0, and predetermined coefficient a, as well as detection values, such as peak-to-peak values ​​(PP values), output from the sensors 9a, 9b of the power transmission unit 8. The coupling coefficient k is obtained based on the mutual inductance Lm and the known self-inductances of the primary coil 8a and the secondary coil 31a.

[0052] For example, when the coupling coefficient k estimated in the searching state of each transmitting power converter 7 reaches a predetermined value ka or more within a predetermined time, the transmitting side control device 9 transitions each transmitting power converter 7 from the searching state to the power transmission control state. The predetermined value ka is, for example, a value corresponding to a predetermined value (e.g., 80%) of the efficiency of power transmission (e.g., overall efficiency). The power transmission control state of each transmitting power converter 7 is, for example, a state in which power transmission is controlled at the power and frequency requested by the power receiving device 4. On the other hand, for example, if the coupling coefficient k estimated in the search state of each transmission power conversion unit 7 does not reach a predetermined value ka or more within a predetermined time, the transmission side control device 9 returns each transmission power conversion unit 7 from the search state to a reception standby state. The control operation of the power transmitting side control device 9 will be described in detail later.

[0053] 1, 2, and 3, the drive control device 3 of the vehicle V includes, for example, a power storage device 11, a power conversion unit 13, and a rotating electric machine 14. The power receiving device 4 of the vehicle V includes, for example, a power receiving unit 15 and a received power conversion unit 16. The drive control device 3 and the power receiving device 4 include, for example, a common power receiving-side control device 17.

[0054] The power storage device 11 is connected to a power conversion unit 13 and a received power conversion unit 16, which will be described later. The power storage device 11 is charged by power transmitted contactlessly from a power transmission device 2 outside the vehicle V. The power storage device 11 exchanges power with a rotating electric machine 14 via the power conversion unit 13. The power storage device 11 includes, for example, a battery, a current sensor for detecting the battery current, and a voltage sensor for detecting the battery voltage. The battery is, for example, a secondary battery such as a lead acid battery, a lithium ion battery, a sodium ion battery, a nickel-metal hydride battery, or an all-solid-state battery, a capacitor such as an electric double layer capacitor, or a combined battery that combines a secondary battery and a capacitor.

[0055] The power conversion unit 13 is connected to a rotating electric machine 14. The power conversion unit 13 includes, for example, a second element module that converts between DC power and AC power, and a capacitor for smoothing voltage. The second element module includes, for example, a second bridge circuit formed by a plurality of switching elements and rectifying elements bridge-connected in three phases. Each switching element is, for example, a transistor such as an IGBT (Insulated Gate Bipolar Transistor) or a SiC MOSFET. The plurality of switching elements are high-side arm and low-side arm transistors 13a and 13b that form a pair in each phase. The rectifying elements are, for example, freewheeling diodes connected in parallel to each of the transistors 13a and 13b. A voltage smoothing capacitor 13c is connected in parallel to the second bridge circuit.

[0056] The second element module controls the operation of the rotating electric machine 14 by receiving and sending electric power. For example, when the rotating electric machine 14 is powered, the second element module converts DC power input from the positive and negative DC terminals 13p, 13n into three-phase AC power and supplies the three-phase AC power from the three-phase AC terminals 13d to the rotating electric machine 14. The second element module generates a rotational driving force by sequentially commutating the current to the three-phase stator windings of the rotating electric machine 14. For example, during regeneration of the rotating electric machine 14, the second element module converts three-phase AC power input from the three-phase stator windings into DC power by driving the switching elements of each phase to turn on (conduct) and off (cut) in synchronization with the rotation of the rotating electric machine 14. The second element module can supply the DC power converted from the three-phase AC power to the power storage device 11.

[0057] The rotating electric machine 14 is, for example, a three-phase AC brushless DC motor provided for driving the vehicle V. The rotating electric machine 14 includes a rotor having a permanent magnet for a field, and a stator having three-phase stator windings that generate a rotating magnetic field that rotates the rotor. The three-phase stator windings are connected to three-phase AC terminals 13d of the power conversion unit 13. The rotating electric machine 14 generates rotational driving force by power running using electric power supplied from the power conversion unit 13. When the rotating electric machine 14 is connected to the wheels of the vehicle V, for example, it generates driving force by power running using electric power supplied from the power conversion unit 13. The rotating electric machine 14 may generate electric power by performing regenerative operation using rotational power input from the wheel side of the vehicle V. When the rotating electric machine 14 is connected to the internal combustion engine of the vehicle V, it may generate electric power using the power of the internal combustion engine.

[0058] The power receiving unit 15 is connected to AC terminals of a third bridge circuit of the receiving power conversion unit 16, which will be described later. The power receiving unit 15 receives power by changes in a high-frequency magnetic field transmitted from the power transmitting unit 8, for example, by magnetic field coupling such as magnetic resonance or electromagnetic induction. As shown in FIG. 4, the power receiving unit 15 includes a resonant circuit formed by, for example, a secondary coil 15a, a secondary resistor 15b, and a secondary capacitor 15c connected in series. The power receiving unit 15 includes sensors such as a current sensor that detects a current (power receiving side current) Ir flowing through the resonant circuit and a voltage sensor that detects a voltage (power receiving side voltage) Vr of the resonant circuit.

[0059] 1, 2, and 3 is connected to the power conversion unit 13. The receiving power conversion unit 16 includes a so-called full-bridgeless (or bridgeless and totem-pole) power factor correction (PFC) circuit that converts AC power into DC power. The so-called bridgeless PFC is a PFC that does not include a bridge rectifier made up of multiple bridge-connected diodes, and the so-called totem-pole PFC is a PFC that includes a pair of switching elements of the same conductivity type that are connected in series in the same direction (totem-pole connection).

[0060] The receiving power conversion unit 16 includes, for example, a third bridge circuit formed by a plurality of switching elements and rectifying elements bridge-connected in two phases, and a voltage smoothing capacitor. Each switching element is, for example, a transistor such as a SiC MOSFET. The plurality of switching elements are high-side arm and low-side arm transistors 16a, 16b that form a pair in each phase. The rectifying element is, for example, a freewheeling diode connected in parallel to each of the transistors 16a, 16b. The voltage smoothing capacitor 16c is connected in parallel to the third bridge circuit. The receiving power conversion unit 16 includes, for example, a sensor such as a current sensor that detects the current of DC power.

[0061] For example, a power receiving device 4 equipped with a power receiving unit 15 and a power receiving power conversion unit 16 receives power transmitted from the power transmitting device 2 by controlling the on (conduction) and off (cutoff) switching of each switching element of the power receiving power conversion unit 16 in accordance with information on the frequency of power transmission by the power transmitting device 2.

[0062] The power receiving side control device 17 comprehensively controls, for example, the drive control device 3, the power receiving device 4, and the in-vehicle communication device 5 of the vehicle V. The power receiving side control device 17 is a software function unit that functions when a predetermined program is executed by a processor such as a CPU (Central Processing Unit). The software function unit is an ECU that includes a processor such as a CPU, a ROM (Read Only Memory) that stores programs, a RAM (Random Access Memory) that temporarily stores data, and electronic circuits such as a timer. At least a part of the power receiving side control device 17 may be an integrated circuit such as an LSI (Large Scale Integration).

[0063] For example, in power reception control during power transmission between the power transmission device 2 and the power receiving device 4, the power receiving side control device 17 controls the current switching operation of each of the drive control device 3 and the power receiving device 4. For example, the power receiving side control device 17 generates control signals indicating the timing to drive each switching element of the drive control device 3 and the power receiving device 4 on (conducting) and off (cutting), and generates gate signals for actually driving each switching element on and off based on the control signals. For example, the power receiving side control device 17 controls the switching of each switching element of the power receiving device 4 to rectify the AC power received from the power transmitting device 2 into DC power and improve the power factor of the input voltage and input current.

[0064] For example, the power receiving side control device 17 controls the output according to the target output by a synchronous rectification operation that synchronously drives multiple switching elements of the power receiving device 4 on and off, and a short-circuit operation that short-circuits the secondary side coil 15a. For example, the power receiving side control device 17 controls the synchronous rectification operation in accordance with the magnitude and phase of the current generated in the power receiving unit 15 by the power transmitted from the power transmitting device 2, i.e., the current Ir flowing through the secondary side coil 15a. The power receiving side control device 17 controls the multiple switching elements of the power receiving power conversion unit 16 by soft switching of so-called zero voltage switching (ZVS). In zero voltage switching (ZVS), each switching element is turned on (switched from an off state to an on state) after the voltage across both ends of the switching element is made zero by discharging the output capacitance (parasitic capacitance) in the off state during the dead time period of each phase.

[0065] For example, the power receiving side control device 17 controls the short-circuit operation by turning on only the low-side arm of each phase while continuing the zero voltage switching (ZVS) synchronous rectification operation in the high-side arm of each phase of the power receiving power conversion unit 16. By short-circuiting the secondary coil 15a, the power receiving side control device 17 increases the secondary-side impedance when the secondary-side power receiving device 4 is viewed from the primary-side power transmitting device 2, thereby reducing the primary-side current (power transmitting side current: current It flowing through the primary-side coil 8a). The power receiving side control device 17 controls the current It of the primary-side power transmitting device 2 by the secondary-side power receiving device 4, thereby performing independent power control such as stopping power transmission on the power receiving device 4 side.

[0066] For example, prior to the start of power transmission between the power transmitting device 2 and the power receiving device 4, the power receiving side control device 17 controls communication between the power transmitting device 2 and the power receiving device 4 via the primary side coil 8a and the secondary side coil 15a. Fig. 6 is a diagram showing an example of communication and power transmission operations accompanying movement of a vehicle V in the embodiment. Fig. 7 is a graph showing an example of the correspondence relationship between power and efficiency according to horizontal distance (the relative movement amount between the primary side coil 8a and the secondary side coil 15a in the direction parallel to the road surface) in the contactless power transmission system 1 of the embodiment. 6 and 7, the power receiving side control device 17 determines, for example, a section in which the degree of coupling between the primary side coil 8a of the power transmitting device 2 and the secondary side coil 15a of the power receiving device 4 is equal to or greater than a predetermined degree near the power transmitting device 2 as a coupling section. The power receiving side control device 17 sets, in the coupling section, a communication section CS (first communication section CS1 and second communication section CS2) for communication between the primary side coil 8a and the secondary side coil 15a and a power transmission section TS for power transmission.

[0067] For example, the power receiving side control device 17 determines a coupling section in which the degree of coupling between the primary side coil 8a and the secondary side coil 15a is equal to or greater than a predetermined degree as a section in which the power transmission efficiency E is equal to or greater than a predetermined value (such as zero).The power receiving side control device 17 determines a section in the coupling section in which the power transmission efficiency E is equal to or greater than a first predetermined value Ea (such as 80%) and the relative horizontal distance between the primary side coil 8a and the secondary side coil 15a is equal to or less than a first predetermined distance La as a power transmission section TS in which the degree of coupling between the primary side coil 8a and the secondary side coil 15a is relatively high. The power receiving-side control device 17 determines, within the coupling section, a section where the efficiency of power transmission is less than a first predetermined value Ea and equal to or greater than a second predetermined value Eb (e.g., 0%) and where the relative horizontal distance between the primary coil 8a and the secondary coil 15a is greater than the first predetermined distance La and equal to or less than the second predetermined distance Lb as a communication section CS where the degree of coupling between the primary coil 8a and the secondary coil 15a is relatively low. The communication section CS is, for example, a first communication section CS1 and a second communication section CS2 set before and after the power transmission section TS along the direction of movement of the vehicle V. Note that a state in which the horizontal distance is zero refers, for example, to a state in which the central axes of the primary coil 8a and the secondary coil 15a are aligned. The power P transmitted in the power transmission section TS is regulated, for example, to be equal to or less than an appropriate required power Pa.

[0068] For example, when the power receiving-side control device 17 receives key information and information about the installation of the power transmitting device 2 through communication between the roadside communication device Ma of the communication system M and the in-vehicle communication device 5 before the vehicle V arrives at the coupling section, the power receiving-side control device 17 sets the communication timing for the first communication section CS, i.e., the first communication section CS1, for each of the multiple power transmitting units 8, depending on, for example, information such as the installation intervals of the multiple power transmitting units 8 and the distance from the roadside communication device Ma, and the traveling state of the vehicle V (i.e., the moving state of the power receiving device 4).

[0069] For example, when the power receiving unit 15 reaches the first communication section CS1 of the appropriate power transmitting unit 8, the power receiving-side control device 17 transitions the power receiving device 4 from the short-circuit state to the transmission state. The short-circuit state of the power receiving device 4 is a state in which the secondary coil 15a is short-circuited by turning on the low-side arm transistors 16b of each phase of the power receiving power conversion unit 16. The transmission state of the power receiving device 4 is a state in which the secondary coil 15a transmits second information to the power transmitting power conversion unit 7 and primary coil 8a in a reception standby state by a so-called ping signal. The power receiving-side control device 17 communicates, for example, by a voltage induced in the primary coil 8a of the power transmitting device 2 by a magnetic field generated in the secondary coil 15a by a current switching operation by switching in the power receiving power conversion unit 16. The power receiving side control device 17 executes the PING transmission by, for example, generating a two-level digital signal, so-called dominant and recessive, by switching a carrier wave for contactlessly transmitting power from the secondary side coil 15a to the primary side coil 8a at a predetermined duty ratio. The predetermined duty ratio is, for example, a predetermined minimum to about 50%. Note that the power receiving side control device 17 may transmit the second information by, for example, amplitude modulating the carrier wave by changing the switching duty ratio.

[0070] The power receiving side control device 17 transmits PING signals at a predetermined cycle, for example, from several tens of microseconds to several milliseconds, and transmits information about power transmission in the power transmission section TS as second information from the secondary side coil 15a to the primary side coil 8a. The information about power transmission includes, for example, key information acquired by the in-vehicle communication device 5 from the roadside communication device Ma, a required frequency for power transmission, a target output (power consumption) for fail-safe purposes, and information about various abnormalities. The required power for power transmission is a target value of the power that the power receiving device 4 receives from the power transmitting device 2, and is set, for example, according to the target driving force of the vehicle V or the rotating electric machine 14, the power consumption of various auxiliary machines connected to the power storage device 11, and the remaining capacity (SOC: State Of Charge) of the power storage device 11, etc. The required frequency of power transmission is a frequency required for power transmission from the power transmitting device 2 and is set according to the required power. The required frequency is set so as to suppress a decrease in the efficiency of power transmission and output (power) based on, for example, the minimum ground clearance of the vehicle V, which is related to the distance between the primary coil 8a and the secondary coil 15a, and the mounting layout of the power receiving device 4 on the vehicle V. The required frequency may be set according to, for example, the state of power transmission between the power transmitting device 2 and the power receiving device 4.

[0071] For example, when the power receiving side control device 17 completes at least a predetermined number of (e.g., one) PING transmissions, the power receiving device 4 transitions from the transmission state to the power receiving standby state. The power receiving standby state of the power receiving device 4 is a state in which the power receiving device 4 receives power transmitted from the power transmitting power converter 7 and the primary coil 8a in the searching state. For example, when the received power detected in the power receiving standby state reaches or exceeds a predetermined power within a predetermined time, that is, when the power receiving unit 15 reaches the power transmission section TS, the power receiving side control device 17 transitions the power receiving device 4 from the power receiving standby state to the power receiving control state. The predetermined power is, for example, a predetermined value (e.g., 80%) of the efficiency of power transmission (e.g., overall efficiency), that is, a value corresponding to a predetermined value ka of the coupling coefficient k estimated by the power transmitting side control device 9. On the other hand, the receiving side control device 17 returns the power receiving device 4 from the power receiving standby state to the transmission state, for example, if the received power detected in the power receiving standby state does not reach a predetermined power level or more within a predetermined time, that is, if the power receiving unit 15 has not reached the power transmission section TS.

[0072] In addition, for example, when the power receiving unit 15 is located in the second communication section CS2, the power receiving side control device 17 may send information indicating the stoppage of power transmission in the power transmission section TS and communication in the communication section CS from the secondary side coil 15a to the primary side coil 8a. The control operation of the power receiving side control device 17 will be described in detail later.

[0073] Hereinafter, as the operation of the contactless power transfer system 1, the processes executed by the power transmitting side controller 9 and the power receiving side controller 17 will be described. FIG. 8 is a flowchart showing the power receiving side process executed by the power receiving side control device 17 of the contactless power transfer system 1 in the embodiment. First, in step S01 shown in FIG. 8, the power receiving side control device 17 sets the power receiving device 4 in a short-circuit state. Next, in step S02, the power receiving-side control device 17 determines whether electronic payment for the power transmission from the power transmitting device 2 to the vehicle V is possible through wireless communication (billing communication) between the roadside communication device Ma of the communication system M and the in-vehicle communication device 5. If the determination result is "NO", the power receiving-side control device 17 repeats the processing of step S02. On the other hand, if the determination result is "YES", the power receiving-side control device 17 proceeds to step S03.

[0074] Then, in step S03, the power receiving side control device 17 acquires key information required to start power transmission from the roadside communication device Ma via the in-vehicle communication device 5. Next, in step S04, the power receiving-side control device 17 transitions the power receiving device 4 from the short-circuit state to the transmission state, for example, when the power receiving unit 15 reaches the first communication section CS1 of the appropriate power transmitting unit 8. The power receiving-side control device 17 generates a signal for PING transmission from the secondary side coil 15a of the power receiving device 4 to the primary side coil 8a of the appropriate power transmitting unit 8 of the power transmitting device 2. Next, in step S05, the power receiving side control device 17 executes PING transmission to the primary coil 8a of the appropriate power transmission unit 8 of the power transmission device 2 at a predetermined cycle in the first communication section CS1.

[0075] Next, in step S06, when the power receiving side control device 17 has completed transmitting PING signals at least a predetermined number of times (for example, once), the power receiving device 4 transitions from the transmission state to the power receiving standby state. Next, in step S07, the power receiving-side control device 17 determines whether or not a response signal to the PING transmission has been received from the power transmitting unit 8. If the result of this determination is "NO", the power receiving-side control device 17 repeats the process of step S07. On the other hand, if the result of this determination is "YES", the power receiving-side control device 17 proceeds to step S08.

[0076] Next, in step S08, the power receiving-side control device 17 executes power receiving control for the power transmission from the power transmitting device 2 in the power transmission section TS. Then, the power receiving-side control device 17 advances the process to the end.

[0077] FIG. 9 is a flowchart showing the power transmission side process executed by the power transmission side control device 9 of the contactless power transmission system 1 in the embodiment. First, in step S21 shown in FIG. 9, the power transmitting side control device 9 sets the power transmitting device 2 to a stopped state. Next, in step S22, the power transmitting side control device 9 determines whether or not key information has been transmitted from the roadside communication device Ma to the power receiving device 4. If the determination result is "NO", the power transmitting side control device 9 proceeds to step S23. On the other hand, if the determination result is "YES", the power transmitting side control device 9 proceeds to step S24. Then, in step S23, the power transmitting side control device 9 maintains the stopped state of the power transmitting device 2, and returns the process to step S22. Then, in step S24, the power transmitting side control device 9 causes the power transmitting device 2 to transition from the stopped state to the reception standby state.

[0078] Next, in step S25, the power transmitting side control device 9 determines whether or not a PING signal transmitted from the secondary side coil 15a to the primary side coil 8a has been received in the first communication section CS1 of any of the transmitters 8. If the determination result is "NO", the power transmitting side control device 9 repeats the process of step S25. On the other hand, if the determination result is "YES", the power transmitting side control device 9 proceeds to step S26. Next, in step S26, the power transmitting side control device 9 compares the key information received in advance from the communication control device Mb with the key information received by the primary side coil 8a from the secondary side coil 15a of the power receiving device 4.

[0079] Next, in step S27, the power transmitting side control device 9 determines whether the key information received from the communication system M (i.e., the same key information as the key information sent from the communication system M to the in-vehicle communication device 5) matches the key information received by the primary side coil 8a from the secondary side coil 15a of the power receiving device 4. If the result of this determination is "YES", that is, if pairing is established between the secondary side coil 15a of the power receiving device 4 and the primary side coil 8a of the power transmitting unit 8 that received the PING signal transmitted from the power receiving device 4, the power transmitting side control device 9 proceeds to step S28. On the other hand, if the result of this determination is "NO", the power transmitting side control device 9 proceeds to end the process. Next, in step S28, the power transmitting side control device 9 transmits a response signal to the PING transmission from the power receiving device 4 to the power receiving device 4 via the paired primary side coil 8a and secondary side coil 15a.

[0080] Next, in step S29, the power transmitting side control device 9 transitions the power transmitting power conversion unit 7 corresponding to the paired primary side coil 8a from a reception standby state to a search state (search mode). In the search state of each power transmitting power conversion unit 7, the power transmitting side control device 9 acquires the mutual inductance Lm and coupling coefficient k between the paired primary side coil 8a and secondary side coil 15a based on the above formulas (1) and (3) and the respective detection values ​​output from the current sensor 9a and voltage sensor 9b of the power transmitting unit 8.

[0081] Next, in step S30, the power transmitting side control device 9 determines whether the coupling coefficient k estimated in the searching state of the power transmitting power conversion unit 7 reaches a predetermined value (predetermined threshold) ka or more within a predetermined time. If the result of this determination is "NO", the power transmitting side control device 9 returns the process to step S24. On the other hand, if the result of this determination is "YES", the power transmitting side control device 9 proceeds to step S31. Then, in step S31, the power transmitting side control device 9 executes power transmission control for power transmission in the power transmission section TS by the power transmitting power converter 7 and the power transmitting device 8. Then, the power transmitting side control device 9 advances the process to END.

[0082] 10 is a diagram showing an example of the correspondence relationship among the power receiving side drive signal, the power receiving side voltage Vr, the power transmitting side voltage Vt, the power receiving side current Ir, and the coupling coefficient k during communication between the primary side coil 8a and the secondary side coil 15a prior to the start of power transmission in the contactless power transmission system 1 of the embodiment. The power receiving side drive signal is a gate signal that drives each switching element of the power receiving converter 16. Before time t1 shown in FIG. 10, when the power transmitting side control device 9 receives information on a combination of key information and information on power transmission from the communication system M, it shifts the power transmitting device 2 from the stopped state to the reception standby state.

[0083] The power receiving side control device 17 transitions the power receiving device 4 from the short-circuit state to the transmission state at time t1 when the power receiving unit 15 reaches the first communication section CS1 of the appropriate power transmitting unit 8. The power receiving side control device 17 executes PING transmission at least a predetermined number of times (such as once) over the period until time t2, and transitions the power receiving device 4 from the transmission state to the power receiving standby state after the PING transmission is completed. When the power transmitting side control device 9 receives the key information via the PING signal, it verifies the key information based on the key information previously received from the communication system M. If the key information received from the communication system M and the power receiving device 4 matches, the power transmitting side control device 9 transitions the power transmitting power conversion unit 7 corresponding to the primary side coil 8a that received the key information from a reception standby state to a search state (search mode).

[0084] From time t2 to time t3, the power transmitting side control device 9 outputs a voltage pulse to the primary side coil 8a by switching the current flow in the power transmitting power conversion unit 7 in the search mode, while estimating the coupling coefficient k between the primary side coil 8a and the secondary side coil 15a based on the current detection in the power transmitting unit 8. If, for example, the coupling coefficient k does not change from an appropriate initial value k0 and does not reach a predetermined value ka or more within a predetermined time, the power transmitting side control device 9 returns the power transmitting power conversion unit 7 from the search mode to the reception standby state at time t3. If the coupling coefficient k does not increase and the received power detected in the power receiving standby state does not reach a predetermined power level or higher within a predetermined time, the power receiving side control device 17 returns the power receiving device 4 from the power receiving standby state to the transmission state at time t3.

[0085] The power receiving side control device 17 again transmits PING at least a predetermined number of times (such as once) over the period from time t3 to time t4, and after completing the PING transmission, transitions the power receiving device 4 from the transmission state to the power receiving standby state. The power transmitting side control device 9 again compares the key information previously received from the communication system M with the key information acquired from the PING signal. If the key information matches, the power transmitting side control device 9 transitions the power transmitting power conversion unit 7 corresponding to the primary side coil 8a that received the key information from the reception standby state to a search state (search mode).

[0086] From time t4 to time t5, the power transmitting side control device 9 again outputs voltage pulses to the primary side coil 8a by switching the current flow in the power transmitting power conversion unit 7 in the search mode, while estimating the coupling coefficient k between the primary side coil 8a and the secondary side coil 15a based on the current detection in the power transmitting unit 8. At time t5, when the coupling coefficient k reaches or exceeds a predetermined value ka within a predetermined time, the power transmitting side control device 9 transitions the power transmitting power conversion unit 7 from the search mode to a power transmission control state. As the coupling coefficient k reaches a predetermined value ka or more, the receiving side control device 17 transitions the receiving device 4 from the power receiving standby state to the power receiving control state at time t5 when the received power detected in the power receiving standby state reaches a predetermined power or more within a predetermined time.

[0087] As described above, the contactless power transmission system 1 of the embodiment includes a communication system M and an in-vehicle communication device 5 that communicate first information (first communication), and a primary side coil 8a and a secondary side coil 15a that communicate second information (second communication) and transmit power contactlessly. This eliminates the need for a special communication device for communicating the second information (second communication), and prevents the system configuration from becoming complicated.

[0088] For example, communication of first information having a large capacity can be performed by the communication system M and the in-vehicle communication device 5, and communication of second information having a small capacity required at least only to identify the vehicle V can be performed by the primary coil 8a and the secondary coil 15a. Since contactless power transmission is performed by the primary coil 8a and the secondary coil 15a that are paired by communication and collation of key information, appropriate power transmission control and power reception control can be performed with high reliability.

[0089] For example, even if multiple combinations of primary coil 8a and transmission power converter 7 are connected to a common power supply 6, the communication and verification of key information and the power transmission are controlled independently for each combination. As a result, even in a mixed traffic environment where there are multiple traveling vehicles V with different power requirements and where inter-vehicle distances are reduced and cutting-in occurs, power can be transmitted individually to each of the multiple traveling vehicles V at appropriate timing, including simultaneous transmission, and with appropriate power. Because communication is performed for each vehicle V via the primary coil 8a and secondary coil 15a in the communication section CS, interference with other vehicles V can be suppressed. Because power transmission is performed via the primary coil 8a and secondary coil 15a in the power transmission section TS adjacent to the communication section CS, appropriate power transmission can be performed to each vehicle V according to its required power.

[0090] By providing a search state (search mode) for the transmission power conversion unit 7, when the degree of coupling (e.g., coupling coefficient k) between the paired primary side coil 8a and secondary side coil 15a reaches or exceeds a predetermined threshold degree (e.g., a predetermined value ka) suitable for power transmission, power transmission control can be performed appropriately.

[0091] By providing a short-circuit state for the receiving power conversion unit 16, it is possible to prevent unnecessary communication from the secondary coil 15a to the primary coil 8a. By providing a power reception standby state for the receiving power conversion unit 16, it is possible to perform appropriate voltage detection in accordance with the search state (search mode) of the transmitting power conversion unit 7. Furthermore, when the received power increases appropriately as the degree of coupling between the paired primary coil 8a and secondary coil 15a increases, it is possible to execute appropriate power reception control.

[0092] (Variation) In the above-described embodiment, the contactless power transfer system 1 may include a storage voltage converter that converts input and output power of the power storage device 11, for example, in the case of a hybrid vehicle or the like that is driven by the power storage device 11 and an internal combustion engine as a power source.

[0093] The embodiments of the present invention are presented as examples and are not intended to limit the scope of the invention. These embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0094] 1...contactless power transfer system, 2...power transmission device, 3...drive control device, 4...power receiving device, 5...on-board communication device (power receiving side communication device), 6...power supply unit (power source), 7...power transmission power conversion unit (power transmission side power conversion unit), 8...power transmission unit, 8a...primary side coil (power transmission side coil), 9...power transmission side control device, 11...energy storage device, 13...power conversion unit, 14...rotating electric machine, 15...power receiving unit, 15a...secondary side coil (power receiving side coil), 16...power reception power conversion unit (power receiving side power conversion unit), 17...power receiving side control device, M...communication system (power transmission side communication device), Ma...roadside communication device, Mb...communication control device, V...vehicle (moving object), R...driving path (moving path).

Claims

1. a power receiving side coil, a power receiving side communication device, and a power receiving side control device mounted on a moving body; a power transmitting device having at least one power transmitting coil, a power transmitting communication device, and a power transmitting control device that are arranged on a moving path of the moving body; Equipped with the power receiving-side communication device and the power transmitting-side communication device exchange first information through first wireless communication before a degree of coupling between the power receiving-side coil and the power transmitting-side coil reaches a predetermined degree or more; the power receiving side coil transmits second information to the power transmitting side coil through second communication using an induced voltage of magnetic field coupling after the first communication between the power receiving side communication device and the power transmitting side communication device or when the power receiving side coil and the power transmitting side coil are within a predetermined distance from each other; the power transmitting side coil contactlessly transmits power to the power receiving side coil after the second communication with the power receiving side coil; the power receiving side control device and the power transmitting side control device control communication of the first information and the second information, and control contactless power transmission between the power receiving side coil and the power transmitting side coil based on the first information and the second information; the first information transmitted from the power receiving-side communication device to the power transmitting-side communication device includes at least information related to power transmission; the first information transmitted from the power transmitting communication device to the power receiving communication device includes at least key information; the second information includes at least the key information, the power transmitting device includes at least one power transmitting side power conversion unit connected to each of the at least one power transmitting side coils and independently converting power supplied from a power source; The power transmitting side control device independently controls contactless power transmission by each of the at least one power transmitting side coil in accordance with the information on power transmission associated with the key information received by each of the at least one power transmitting side coil from the power receiving side coil, based on a combination of the key information and the information on power transmission. Contactless power transmission system.

2. The power transmitting side control device After transmitting the key information from the power transmitting side communication device to the power receiving side communication device, transitioning the power transmitting side power converting unit from a stopped state to a state waiting for reception of the second information; after the power transmitting side coil has completed matching of the key information received from the power receiving side coil, transitioning the power transmitting side power conversion unit from the reception standby state to a searching state in which a voltage pulse is output for estimating the degree of coupling; When the coupling degree reaches or exceeds a predetermined threshold in the search state, the power transmitting side power conversion unit is shifted to a power transmission control state, and when the coupling degree does not reach or exceed the predetermined threshold in the search state, the power transmitting side power conversion unit is shifted to the reception standby state. The contactless power transfer system according to claim 1 .

3. a power receiving side power conversion unit mounted on the moving body and connected to the power receiving side coil, The power receiving side control device After the power receiving-side communication device receives the key information from the power transmitting-side communication device, the power receiving-side power conversion unit is shifted from a state in which the power receiving-side coil is short-circuited to a state in which the second information is transmitted; After transmitting the second information, the power receiving side power conversion unit is shifted from the transmission state to a power reception standby state; When the received power reaches or exceeds a predetermined power within a predetermined time in the power reception standby state, the power receiving side power conversion unit is shifted to a power reception control state, and when the received power does not reach or exceed the predetermined power within the predetermined time in the power reception standby state, the power receiving side power conversion unit is shifted to the transmission state. The contactless power transfer system according to claim 2 .

4. at least one power transmitting coil that is arranged on a path of movement of the moving body and that transmits power in a wireless manner to a power receiving coil that is mounted on the moving body; a power transmitting-side communication device that transmits and receives first information through first wireless communication with a power receiving-side communication device mounted on the mobile object before a degree of coupling between the power transmitting-side coil and the power receiving-side coil reaches a predetermined degree or higher; a power transmitting side control device that controls contactless power transmission between the power receiving side coil and the power transmitting side coil based on second information received by the power transmitting side coil through second communication using an induced voltage of magnetic field coupling between the power receiving side coil and the power transmitting side coil and the first information; Equipped with at least one power transmitting side power conversion unit connected to each of the at least one power transmitting side coils and independently converting power supplied from a power source; the first information received by the power transmitting communication device from the power receiving communication device includes at least information related to power transmission; the first information transmitted from the power transmitting communication device to the power receiving communication device includes at least key information; the second information includes at least the key information, The power transmitting side control device independently controls contactless power transmission by each of the at least one power transmitting side coil in accordance with the information on power transmission associated with the key information received by each of the at least one power transmitting side coil from the power receiving side coil, based on a combination of the key information and the information on power transmission. Power transmission equipment.

5. The power transmitting side control device After transmitting the key information from the power transmitting side communication device to the power receiving side communication device, transitioning the power transmitting side power converting unit from a stopped state to a state waiting for reception of the second information; after the power transmitting side coil has completed matching of the key information received from the power receiving side coil, transitioning the power transmitting side power conversion unit from the reception standby state to a searching state in which a voltage pulse is output for estimating the degree of coupling; When the coupling degree reaches or exceeds a predetermined threshold in the search state, the power transmitting side power conversion unit is shifted to a power transmission control state, and when the coupling degree does not reach or exceed the predetermined threshold in the search state, the power transmitting side power conversion unit is shifted to the reception standby state. The power transmitting device according to claim 4 .

6. a power receiving coil that receives power transmitted contactlessly from the power transmitting coil; a power receiving-side communication device that transmits and receives first information through first wireless communication with a power transmitting-side communication device provided in the power transmitting device before a degree of coupling between the power transmitting-side coil and the power receiving-side coil reaches a predetermined degree or more; a power receiving side control device that transmits second information to the power transmitting side coil through second communication using an induced voltage of magnetic field coupling between the power receiving side coil and the power transmitting side coil; Equipped with a power receiving side power conversion unit connected to the power receiving side coil, the first information transmitted by the power receiving-side communication device to the power transmitting-side communication device includes at least information related to power transmission; the first information received by the power receiving communication device from the power transmitting communication device includes at least key information; the second information includes at least the key information, The power receiving side control device After the power receiving-side communication device receives the key information from the power transmitting-side communication device, the power receiving-side power conversion unit is shifted from a state in which the power receiving-side coil is short-circuited to a state in which the second information is transmitted; After transmitting the second information, the power receiving side power conversion unit is shifted from the transmission state to a power reception standby state; When the received power reaches or exceeds a predetermined power within a predetermined time in the power reception standby state, the power receiving side power conversion unit is shifted to a power reception control state, and when the received power does not reach or exceed the predetermined power within the predetermined time in the power reception standby state, the power receiving side power conversion unit is shifted to the transmission state. Mobile object.

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