Contactless power transmission system, mobile body, and contactless power transmission method

Abstract

To provide a non-contact power transmission system capable of performing more appropriate power transmission even while a mobile is moving, a mobile, and a non-contact power transmission method.SOLUTION: A non-contact power transmission system supplies power from a power feeding device, which is installed in a movement path of a mobile, to a power receiving device which is installed in the mobile, in a non-contact manner. In the non-contact power transmission system, the power receiving device comprises a power receiving section for receiving power in accordance with a change of a magnetic field which is transferred from the power feeding device by magnetic field coupling, and a control section for controlling the power receiving section. The power receiving section includes a switching circuit which is connected between a coil and a resonance capacitor, which are connected in series, and switches a resonance mode in which the resonance capacitor is electrified and a short-circuit mode in which the resonance capacitor is not electrified. The control section controls the switching circuit in such a manner that the mode is switched in accordance with a predetermined condition.SELECTED DRAWING: Figure 6

Description

[Technical Field]

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

[0002] In recent years, research and development has been conducted on charging and supplying 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. In this regard, in a contactless power transmission system that supplies power to a vehicle from outside the vehicle, a technology is known in which communication is performed between the power transmitting side and the power receiving side by superimposing a communication signal on a power supply signal transmitted from the power transmitting side to the power receiving side (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-247807 [Patent Document 2] Patent No. 5348325 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in technology related to charging and supplying power to vehicles equipped with secondary batteries, there has been a problem in that when a moving object such as a vehicle is moving, the distance between the transmitting side and the receiving side changes, and therefore appropriate power transmission may not be possible.

[0005] In order to solve the above-mentioned problems, the present application aims to provide a contactless power transfer system, a mobile object, and a contactless power transfer method that can realize more appropriate control of power transfer even when the mobile object is moving, thereby contributing to energy efficiency. [Means for solving the problem]

[0006] The contactless power transfer system, the moving body, and the contactless power transfer method according to the present invention employ the following configurations. (1): A contactless power transmission system according to one embodiment of the present invention is a contactless power transmission system that contactlessly supplies power from a power supply device installed in a path of travel of a mobile body to a power receiving device installed on the mobile body, wherein the power receiving device includes a power receiving unit that receives power through changes in a magnetic field transmitted from the power supply device by magnetic field coupling, and a control unit that controls the power receiving unit, wherein the power receiving unit is connected between a coil and a resonant capacitor that are connected in series, and includes a switching circuit that switches between a resonant mode in which current is passed through the resonant capacitor and a short mode in which current is not passed through the resonant capacitor, and the control unit controls the switching circuit to switch modes according to predetermined conditions.

[0007] (2) In the above aspect (1), the control unit adjusts the ratio of the short mode in a predetermined time period in accordance with the target power of the power receiving device.

[0008] (3): In the above aspect (1), the control unit determines the ratio of the short mode based on the ratio between the regenerative output value derived based on the power state of the storage unit mounted on the mobile body, the temperature of the storage unit, and the supply voltage from the power supply device, and the predicted future received power value.

[0009] (4): A mobile body according to one embodiment of the present invention is a mobile body equipped with a power receiving device that receives power contactlessly from a power supply device installed on a moving path, and includes a power receiving unit that receives power through changes in the magnetic field transmitted from the power supply device by magnetic field coupling, and a control unit that controls the power receiving unit, wherein the power receiving unit is connected between a coil and a resonant capacitor that are connected in series, and includes a switching circuit that switches between a resonant mode in which current is passed through the resonant capacitor and a short mode in which current is not passed through the resonant capacitor, and the control unit controls the switching circuit to switch modes according to predetermined conditions.

[0010] (5): A contactless power transmission method according to one embodiment of the present invention is a contactless power transmission method for contactlessly supplying power from a power supply device installed in a path of a moving body to a power receiving device installed in the moving body, in which the power receiving device receives power through changes in a magnetic field transmitted from the power supply device by magnetic field coupling, and controls a switching circuit connected between a coil and a resonant capacitor that are connected in series and switches between a resonant mode in which current is passed through the resonant capacitor and a short mode in which current is not passed through the resonant capacitor to switch modes according to predetermined conditions. [Effects of the Invention]

[0011] According to aspects (1) to (5), more appropriate control of power transmission can be achieved even when the moving body is moving. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic configuration diagram of a contactless power transfer system according to an embodiment. [Figure 2] 1 is a diagram illustrating an example of a configuration of a power supply device 100 according to an embodiment. [Figure 3] 1 is a diagram illustrating an example of the configuration of a vehicle 200 according to an embodiment. [Figure 4] FIG. 10 is a diagram illustrating a transition of an operation mode. [Figure 5] FIG. 2 is a diagram illustrating an example of a circuit configuration on a power transmitting side and a power receiving side according to an embodiment. [Figure 6] 2 is a diagram showing an example of the circuit configuration of a power transmitting unit 116 and a power receiving unit 211. FIG. [Figure 7] 10A and 10B are diagrams illustrating an example of a current flow in a switching circuit 211d in a resonance mode and a short mode. [Figure 8] FIG. 10 is a diagram for explaining a method for determining a short mode ratio. [Figure 9] 10 is a flowchart illustrating an example of a power transmission process according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, a contactless power transfer system, a mobile object, and a contactless power transfer method according to an embodiment of the present invention will be described with reference to the drawings.

[0014] [System Configuration] FIG. 1 is a schematic configuration diagram of a contactless power transmission system according to an embodiment. The contactless power transmission system 1 according to the embodiment includes, for example, a power supply device 100, a vehicle 200, which is an example of a mobile object, and an information processing server 300. The power supply device 100 and the information processing server 300 communicate with each other via a network NW. The network NW includes, for example, the Internet, a wide area network (WAN), a local area network (LAN), a cellular network, a public line, a provider device, a wireless base station, and the like. In the contactless power transmission system 1, the vehicle 200 may also communicate with the information processing server 300 via the network NW using an on-board communication device. In the contactless power transmission system 1, the power supply device 100 and the vehicle 200 communicate with each other using other communication means, which will be described later. In the contactless power transmission system 1, the vehicle 200 is, for example, an electric vehicle, a hybrid vehicle, a fuel cell vehicle, or the like. In addition to the vehicle 200, the mobile object according to the embodiment may be an object capable of moving along a path, such as an electric robot. Furthermore, the moving body may or may not have a person on board. Furthermore, the moving body may be configured to be capable of automatic driving as well as manual driving by a passenger (driver). In the following description, the moving body is assumed to be a vehicle.

[0015] The contactless power transfer system 1 supplies power from the power transfer device 100 to the vehicle 200 by contactless power transfer between the power transfer device 100 and the vehicle 200. In the contactless power transfer system 1, the power transfer device 100 supplies power to a plurality of vehicles 200, and the vehicles 200 receive power from a plurality of power transfer devices 100. However, for convenience of explanation, the following description will mainly focus on one-to-one contactless power transfer.

[0016] The power supply devices 100 are installed (buried) at predetermined intervals on the road surface of a predetermined power supply lane (e.g., lane L1) among lanes L1 and L2 (examples of travel paths) on which the vehicle 200 can travel (e.g., power supply devices 100-1, 100-2, 100-3, etc. shown in FIG. 1 ). The predetermined intervals are intervals at which the magnetic field coupling regions of the power supply devices 100 do not overlap. The predetermined intervals may be set according to the type of road (e.g., an ordinary road or an expressway) or according to traffic regulations such as the speed limit of the road. The power supply device 100 communicates with the vehicle 200 approaching within a predetermined distance, and supplies power in response to a power supply request from the vehicle 200. The power supply device 100 also performs processing related to power control and power protection functions (e.g., FSA (Fail Safe Action)) in response to the request.

[0017] Vehicle 200 is equipped with a power receiving device 210. Power receiving device 210 is installed at the bottom of vehicle 200 so as to easily receive power from a power supply device installed on the road surface, but the installation location is not limited to this. Power receiving device 210 performs processes related to, for example, vehicle energy management and power protection functions (e.g., FSA). Vehicle 200 also uses power stored in a power storage unit such as a battery to travel and supplies power to other in-vehicle devices. Vehicle 200 also communicates with power supply devices 100-1 to 100-3 while traveling in a power supply lane (lane L1) and charges the power storage unit installed in vehicle 200 using power supplied in response to requests. In wireless power transfer system 1, a communication system required between power supply device 100 and vehicle 200 is a system that can at least individually identify vehicle 200 and can communicate when vehicle 200 is traveling at a speed V1 of approximately 0 to 100 km / h. The functional configurations of the power supply device 100 and the vehicle 200 will be described in detail later.

[0018] The information processing server 300 may be, for example, a server device or a PC (Personal Computer), or may be a cloud server configured by cloud computing including one or more information processing devices. The information processing server 300 communicates with the power supply device 100, the vehicle 200, and the like, and performs various processes related to power. The information processing server 300 may be, for example, a billing system for contactless power supply, a power input system, or a system linked to these systems. The billing system is, for example, a system that individually recognizes the vehicle 200 and collects fees according to the power charged. The power bidding system is, for example, a system that performs various controls and management to conduct low-cost power bidding based on demand forecasts. The information processing server 300 also manages the status of the power supply device 100, calculates the power supplied to the vehicle 200 from each of the power supply devices 100-1 to 100-3, and calculates and manages the actual power transmitted to each vehicle 200.

[0019] [Power supply device] 2 is a diagram illustrating an example of the configuration of a power supply device 100 according to an embodiment. The power supply device 100 includes, for example, a power transmitting device 110, a communication control unit 120, and a power supply-side communication unit 130. The power transmitting device 110 includes, for example, a power supply unit 112, a power transmission power conversion unit 114, a power transmitting unit 116, and a power transmitting-side control unit 118. Some or all of the power transmitting-side control unit 118 and the communication control unit 120 are implemented by, for example, a hardware processor such as a CPU (Central Processing Unit) executing a program (software). Some or all of these components may be implemented by hardware (including circuitry) such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), a GPU (Graphics Processing Unit), or an SOC (System On Chip), or may be implemented by a combination of software and hardware. The program may be stored in advance in a storage device (a storage device with a non-transitory storage medium) such as an HDD (Hard Disk Drive) or flash memory of the power supply device 100, or may be stored in a removable storage medium such as a DVD or CD-ROM, and installed in the HDD or flash memory of the power supply device 100 by inserting the storage medium (non-transitory storage medium) into a drive device.

[0020] The power supply unit 112 of the power transmitting device 110 is connected to the transmission power conversion unit 114. The power supply unit 112 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 capacitor for smoothing power. The power supply unit 112 converts, for example, AC power supplied from the AC power supply into DC power using the AC-DC converter. Furthermore, the power supply unit 112 performs a power smoothing process using a capacitor during power conversion.

[0021] The transmission power conversion unit 114 is connected to the power transmission unit 116. The transmission power conversion unit 114 includes, for example, an inverter that converts DC power into AC power. The inverter includes, for example, a bridge circuit formed by a plurality of switching elements and rectifier elements that are bridge-connected in two phases, and a resonance capacitor for adjusting the resonance of the coil. The circuit configuration of the transmission power conversion unit 114 will be described in detail later.

[0022] The power transmitting unit 116 transmits power to the outside (for example, the power receiving device 210 of the vehicle 200) by changing a high-frequency magnetic field, for example, by magnetic field coupling due to magnetic field resonance. In magnetic field resonance, for example, when a current flows through a power transmitting coil, a magnetic field oscillation occurs, and this is transmitted to a resonant circuit on the power receiving side that resonates at the same frequency, causing a current to flow. Also, a known coupling method such as electromagnetic induction may be used for magnetic field coupling. In electromagnetic induction, for example, power is transmitted by utilizing an induced magnetic flux generated between the power transmitting side and the power receiving side.

[0023] The power transmitting-side control unit 118 comprehensively controls each function of the power transmitting device 110 or the entire power supply device 100. For example, the power transmitting-side control unit 118 controls pairing and the like based on information (e.g., a pairing signal or a power receiving-side operation mode) obtained by the power supply-side communication unit 130 communicating with the vehicle-side communication unit 230 of the vehicle 200. The pairing signal includes, for example, a power receiving device ID, which is identification information for identifying the power receiving device 210, or a vehicle ID, which is identification information for identifying the vehicle 200, parameter information such as required power, battery voltage, and the like. For example, the power transmitting-side control unit 118 identifies the power receiving device 210 or the vehicle 200 based on the power receiving device ID or the vehicle ID and establishes (completes) pairing. Furthermore, the power transmitting-side control unit 118 may refer to user information, etc., registered in advance based on the power receiving device ID or the vehicle ID, and establish pairing if the user is capable of supplying power (can use the power supply service). The power transmission side control unit 118 controls the power transmission so that power is supplied to the vehicle 200 with which pairing has been established.

[0024] The power receiving side operation mode is an operation mode of the power receiving device 210 (described later) mounted on the vehicle 200, and includes, for example, a short mode, a parameter transmission mode, a standby mode, and a power receiving mode. The short mode is a mode that prevents unexpected power reception and is used, for example, in FSA and the like. The parameter transmission mode is a mode that transmits parameter information. The standby mode is, for example, a mode that waits for communication with the power supply side. The power receiving mode is a mode in which pairing is established and the power receiving unit 211 and the power receiving power conversion unit 212 are operating and waits for power reception, or is in a state where power can be received or is currently being received based on a predetermined frequency (a required frequency for resonance).

[0025] Furthermore, the power transmitting side control unit 118 controls the operation mode (power transmitting side operation mode) of the power transmitting device 110 depending on the situation. Examples include an off mode, a search mode, a standby mode, and a power transmission mode. The off mode among the power transmitting side operation modes is a mode in which there is no vehicle providing service within the power transmission service section (electric road) and the power transmitting device is not operating. The search mode is a mode in which pairing with the vehicle 200 is established, the coupling coefficient increases, and a situation is detected in which power transmission efficiency can be ensured, and power transmission is suspended. The standby mode is, for example, a mode in which communication with the power receiving side is on standby. The power transmission mode is, for example, a state in which power can be transmitted based on a requested frequency or a state in which power is being transmitted (power transmission state).

[0026] For example, when pairing with the vehicle 200 is established, the power transmitting side control unit 118 transitions the operation mode of the power transmitting device 110 from the off mode to the reception (standby) mode. Furthermore, upon receiving information such as a requested frequency for power transmission from the power receiving device 210 via the communication control unit 120, the power transmitting side control unit 118 transitions the power transmitting device 110 from the reception mode to the search mode. Furthermore, when a state in which power transmission efficiency can be ensured is reached in the search mode, the power transmitting side control unit 118 transitions to the power transmission mode. Furthermore, in the power transmission state of the power transmission mode, the power transmitting side control unit 118 controls the on (conduction) and off (cutoff) switching of each switching element of the power transmitting power conversion unit 114 in accordance with a preset drive frequency or information on a requested frequency (resonance frequency) received from the vehicle 200 side, thereby transmitting power to the power receiving device 210 of the vehicle 200. Furthermore, for example, when power transmission to the vehicle 200 side or communication becomes impossible, the power transmitting side control unit 118 ends pairing and puts the power transmitting device 110 into a sleep state.

[0027] Furthermore, the power transmitting-side control unit 118 may control billing and settlement according to the amount of power used [kWh] after using the system on the vehicle 200 side. The power transmitting-side control unit 118 performs the various controls described above based on various information obtained through communication between the power supply-side communication unit 130 and the vehicle-side communication unit 230.

[0028] The communication control unit 120 controls the operation of the power supply-side communication unit 130. For example, if there are multiple power supply-side communication units 130, the communication control unit 120 controls the operation of all of the power supply-side communication units 130. For example, the communication control unit 120 attempts to acquire predetermined information (e.g., a pairing signal or information related to power transmission (e.g., a required frequency, information required for billing and settlement after system use, etc.)) through communication between the power supply-side communication unit 130 and the vehicle-side communication unit 230 of the surrounding vehicle 200 at a timing such as a predetermined cycle. The communication control unit 120 outputs the acquired information to the power transmission-side control unit 118, and transmits information acquired from the power transmission-side control unit 118 (pairing establishment information, information required for starting power transmission), etc. to the vehicle-side communication unit 230 via the power supply-side communication unit 130.

[0029] The power supply-side communication unit 130 includes an antenna for wireless communication and communicates wirelessly with external devices (for example, the information processing server 300 and the vehicle 200). The power supply-side communication unit 130 also transmits and receives information relating to power transmission from the power transmitting device 110 to the vehicle 200, for example. Specifically, the power supply-side communication unit 130 transmits and receives information for pairing with the vehicle 200 so that power is supplied to a specific vehicle 200 under the control of the power transmitting-side control unit 118 and the communication control unit 120, and transmits and receives information for adjusting the amount of power to be transmitted. The power supply-side communication unit 130 may also acquire information from other external devices via the network NW.

[0030] [vehicle] FIG. 3 is a diagram illustrating an example of the configuration of a vehicle 200 according to an embodiment. The vehicle 200 includes, for example, a power receiving device 210, a rotating electric machine 220, and a vehicle-side communication unit 230. Although not shown in FIG. 3, the vehicle 200 also includes various devices (such as a driving control device) for driving the vehicle on a road manually or automatically, and various on-board devices (examples of loads and accessories) such as a car navigation system and an audio system. The power receiving device 210 includes, for example, a power receiving unit 211, a received power conversion unit 212, a power conversion unit 213, a power storage unit 214, and a vehicle-side control unit (an example of a control unit) 215. The vehicle-side control unit 215 is implemented, for example, by a hardware processor such as a CPU executing a program (software). Some or all of these components may be implemented by hardware (including circuitry) such as an LSI, ASIC, FPGA, or GPU, or by a combination of software and hardware. The program may be stored in advance in a storage device (a storage device having a non-transitory storage medium) such as an HDD or flash memory of the vehicle 200 or the power receiving device 210, or may be stored in a removable storage medium such as a DVD or CD-ROM, and installed in the HDD or flash memory of the vehicle 200 or the power receiving device 210 by inserting the storage medium (non-transitory storage medium) into a drive device.

[0031] The power receiving unit 211 of the power receiving device 210 is connected to the received power conversion unit 212. The power receiving unit 211 receives power by changes in the high-frequency magnetic field transmitted from the power transmitting unit 116 due to magnetic field coupling such as magnetic resonance or electromagnetic induction.

[0032] The receiving power conversion unit 212 is connected to the power conversion unit 213. The receiving power conversion unit 212 converts, for example, AC power into DC power. The receiving power conversion unit 212 includes, for example, a bridge circuit formed by a plurality of switching elements and rectifier elements bridge-connected in two phases, and a capacitor for smoothing voltage. The circuit configuration of the receiving power conversion unit 212 will be described in detail later.

[0033] For example, the power receiving device 210, which includes a power receiving unit 211 and a power receiving power conversion unit 212, receives power transmitted from the power transmitting device 110 by controlling the on (conducting) and off (cutting) switching of each switching element of the power receiving power conversion unit 212 according to information on the frequency of power transmission by the power transmitting device 110 under the control of the vehicle-side control unit 215.

[0034] The power conversion unit 213 is connected to the rotating electric machine 220. The power conversion unit 213 includes, for example, a power converter that converts between DC power and AC power. The power converter includes, for example, an element module and a capacitor for voltage smoothing. The element module includes, for example, a bridge circuit formed by a plurality of switching elements and rectifier elements that are bridge-connected in three phases. The element module controls the operation of the rotating electric machine 220 by exchanging power.

[0035] For example, when the rotating electric machine 220 is powered, the element module converts DC power input from the positive and negative DC terminals into three-phase AC power and supplies the three-phase AC power to the rotating electric machine 220 from the three-phase AC terminals. The element module generates a rotational driving force by sequentially commutating the current to the three-phase stator windings of the rotating electric machine 220. Furthermore, when the rotating electric machine 220 is regenerating, the element module converts the 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 (conductive) and off (interrupted) in synchronization with the rotation of the rotating electric machine 220. The element module can supply the DC power converted from the three-phase AC power to the power storage unit 214.

[0036] The rotating electric machine 220 is, for example, a three-phase AC brushless DC motor provided for driving a vehicle. The rotating electric machine 220 includes a rotor having a permanent magnet for a field and a stator having a three-phase stator winding that generates a rotating magnetic field that rotates the rotor. The three-phase stator winding is connected to three-phase AC terminals of the power conversion unit 213. The rotating electric machine 220 generates a rotational driving force by performing a power running operation using electric power supplied from the power conversion unit 213. For example, if the rotating electric machine 220 can be connected to the wheels of the vehicle 200, the rotating electric machine 220 generates a driving force for driving the vehicle by performing a power running operation using electric power supplied from the power conversion unit 213. The rotating electric machine 220 may generate electric power by performing a regenerative operation using rotational power input from the wheels of the vehicle 200. If the rotating electric machine 220 can be connected to an internal combustion engine of the vehicle 200, the rotating electric machine 220 may generate electric power using the power of the internal combustion engine.

[0037] The power storage unit 214 includes, for example, a battery (an example of a secondary battery) such as a lithium ion battery, a current sensor that detects the battery current, a voltage sensor that detects the battery voltage, and a temperature sensor that measures the battery temperature. The power storage unit 214 is connected to the power conversion unit 213 and the received power conversion unit 212, which will be described later. For example, under the control of the vehicle-side control unit 215, the power storage unit 214 stores power from the power supply device 100 or the rotating electric machine 220 and supplies the stored power to the rotating electric machine 220 and various other on-board devices (loads, auxiliaries).

[0038] Vehicle-side control unit 215, for example, comprehensively controls each function of power receiving device 210 or vehicle 200 as a whole. For example, vehicle-side control unit 215 generates control signals indicating the timing to drive each switching element 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, vehicle-side control unit 215 controls the switching of each switching element of power receiving device 210 to rectify AC power received from power transmitting device 110 into DC power, while improving the power factor of the input voltage and input current.

[0039] Furthermore, the vehicle-side control unit 215 generates predetermined information (e.g., a pairing signal or information related to power transmission) for transmitting power from the power supply device 100 and transmits the generated signal from the vehicle-side communication unit 230 to the outside. The vehicle-side control unit 215 may transmit the pairing signal at a predetermined cycle or at other predetermined timing. When the vehicle-side control unit 215 receives permission information (pairing completion information) indicating that power supply device 100 is able to supply power or information necessary for starting power transmission from the vehicle-side communication unit 230, the vehicle-side control unit 215 obtains target power by performing a synchronous rectification operation that synchronously drives multiple switching elements of the power receiving device 210 to turn on and off, and a short-circuit operation that short-circuits the secondary-side coil, which will be described later. The vehicle-side control unit 215 also controls the current of the power transmitting device 110 to perform independent power control, such as stopping power transmission, on the power receiving device 210 side.

[0040] The information related to power transmission includes, for example, the required power and required frequency of power transmission, a target output (power consumption) for fail-safe purposes, and information related to various abnormalities. The required power of power transmission is a target value of power that the power receiving device 210 receives from the power transmitting device 110, and is set, for example, in accordance with the target driving force of the vehicle 200 or the rotating electric machine 220, the power consumption of various auxiliaries connected to the power storage unit 214, and the power state (SOC: State of Charge) of the power storage unit 214. The power state includes, for example, the remaining capacity and charging rate of the power storage unit 214. The required frequency of power transmission is a frequency required for power transmission from the power transmitting device 110 and is set in accordance with the required power. The required frequency is set, for example, based on the minimum ground clearance of the vehicle 200 and the installation layout of the power receiving device 210 on the vehicle 200, so as to suppress a decrease in the efficiency of power transmission and the output (power). The required frequency may be set, for example, in accordance with the state of power transmission between the power transmitting device 110 and the power receiving device 210. Furthermore, the information regarding power transmission may include information necessary for billing and settlement after use of the system.

[0041] Furthermore, the vehicle-side control unit 215 controls the operation mode of the power receiving device 210. The operation modes include, for example, the short mode, parameter transmission mode, standby mode, and power receiving mode as described above. In the power receiving mode, for example, pairing with the power supply device 100 is established, and the power receiving unit 211 and the received power conversion unit 212 are operated to be able to receive power by magnetic field coupling such as magnetic field resonance or electromagnetic induction.

[0042] For example, the vehicle-side control unit 215 transmits a pairing signal at a predetermined cycle of about several tens of μs to several ms, and upon receiving a response signal to the pairing signal from the power supply device 100, the vehicle-side control unit 215 transitions the operation mode of the power receiving device 210 from a sleep mode to a power receiving mode and starts power reception control for power transmission from the power supply device 100 in the power transmission section. Furthermore, when power reception is completed, the vehicle-side control unit 215 transitions the operation mode of the power receiving device 210 from the power receiving mode to a standby mode.

[0043] The vehicle-side communication unit 230 includes an antenna for wireless communication and communicates wirelessly with external devices (for example, the information processing server 300 and the power supply device 100). The vehicle-side communication unit 230 transmits and receives information related to power transmission from the power supply device 100, for example. Specifically, the vehicle-side communication unit 230 transmits and receives information for pairing with the power supply device 100 so that power is supplied from a specific power supply device 100 under the control of the vehicle-side control unit 215, and transmits and receives information for adjusting the amount of power to be transmitted. The vehicle-side communication unit 230 may also acquire information from other external devices via the network NW.

[0044] [Transition of operation modes in contactless power transfer] Next, transitions of the operation modes of the power transmitting device 110 and the power receiving device 210 in contactless power feeding will be described with reference to the drawings. FIG. 4 is a diagram for explaining transitions of the operation modes. In the example of FIG. 4, the horizontal axis represents time, and the vertical axis represents the operation of the vehicle 200, the operation mode of the power receiving device 210 (VA operation), and the operation mode of the power feeding device 100 (GA operation). Note that the operation transitions in FIG. 4 illustrate, as an example, a case where contactless power transmission is performed between the power feeding device 100 and the power receiving device 210 while the vehicle 200 is traveling at a predetermined speed (for example, approximately 80 km / h). The operation transitions over time will be described below. Note that in the example of FIG. 4, in contactless power feeding, FSA (Fail Safe Action) is always executed on the power receiving device 210 side and the power feeding device 100 side, and FSA is executed to control to the safe side when an abnormality is detected (VA-side FSA, GA-side FSA).

[0045] At time T1, vehicle-side control unit 215 of vehicle 200 communicates with information processing server 300 or the like via vehicle-side communication unit 230, for example, and performs billing processing for contactless power feeding or preliminary processing for billing corresponding to the amount of power to be fed (in-vehicle device billing). Note that, prior to time T1, the operation mode of power receiving device 210 is in standby mode. Also, during the billing processing, the operation mode of the power feeding device is in off mode.

[0046] At time T2, after the billing process is completed, the power receiving device 210 aligns the vehicle 200 so that the vehicle passes over the power supply device 100 installed on the road surface (for example, a power supply lane). In this case, the alignment is performed by displaying an image showing the position of the power supply device 100 (or the position of the power supply lane) and the current position of the vehicle 200 on a display unit (not shown) or the like mounted on the vehicle 200, and the driver manually drives the vehicle 200 while viewing the image displayed on the display unit. Alternatively, if the vehicle 200 includes a recognition unit (not shown) that recognizes the surrounding conditions of the vehicle 200 using an image captured by an on-board camera or the like, or a driving control unit (not shown) that controls at least one of the steering and speed of the vehicle 200 based on the surrounding conditions, the alignment may be performed by control executed by the driving control. For example, when the driving control unit is executing LKAS (Lane Keeping Assistance System) control (lane keeping control), the vehicle 200 is controlled to travel in the center of the lane, and therefore, by performing LKAS control to travel on the power supply lane, alignment can be achieved. Note that from time T2 to T3, the power receiving device 210 remains short-circuited, and the power supply device 100 transitions from the off mode to the standby (waiting) mode.

[0047] At time T3, when the distance between power receiving device 210 and power supply device 100 becomes within a predetermined distance (a distance at which communication is possible) due to vehicle 200 traveling, vehicle-side control unit 215 of vehicle 200 starts pairing by communication (VA-GA communication) between power receiving device 210 and power supply device 100. Between times T3 and T4, until the efficiency of power transmission becomes greater than a predetermined value (for example, greater than 0%), vehicle-side control unit 215 alternates between a transmission mode in which parameter information (ID, required power, battery voltage, etc.) is transmitted and a standby mode. Meanwhile, power transmission-side control unit 118 of power supply device 100 alternates between a reception mode and a search mode. In the search mode, for example, the power transmission efficiency is obtained from the correspondence information of the power (transmission power) and efficiency of the power transmission corresponding to the horizontal distance (the relative movement amount between the primary coil and the secondary coil in the direction parallel to the road surface) in the contactless power transmission system 1 of the embodiment, which is preset. The power transmission side control unit 118 also determines the efficiency based on the ratio of the voltage to the current. If the efficiency is below a predetermined value, the power transmission side control unit 118 outputs information to that effect to the power receiving device 210, causing the power receiving device 210 to execute a retry operation. That is, in this embodiment, if the transmission efficiency is not suitable for power supply, the above-described pairing-related communication can be performed. For example, when the vehicle 200 is traveling at a speed of 80 km / h, the expected period from time T3 to T4 (expected communication completion time) is approximately 22.5 msec.

[0048] At time T4, the efficiency of power transmission exceeds a predetermined value, and therefore power transmission control is executed. For example, the power supply device 100 performs power control (GA power control) to transmit power corresponding to the required power specified by the parameters to the outside. The power receiving device 210 performs power control (VA charging (power reception) control) to receive the power transmitted from the power supply device 100 and store the power in the power storage unit 214 mounted on the vehicle 200. That is, the power supply device 100 performs communication (pairing communication) with the power receiving device 210 when the efficiency of power transmission with the power receiving device 210 is equal to or lower than a predetermined value, and performs power supply control to the power receiving device 210 when the efficiency exceeds the predetermined value. This allows the pairing communication to be completed when the power transmission efficiency is low, and allows power to be supplied more efficiently when the power transmission efficiency is high.

[0049] At time T5, the power transmission efficiency falls below a predetermined value, and therefore the power supply operation is terminated at this time. This allows power supply control using efficient power transmission. For example, when vehicle 200 is traveling at 80 km / h, the expected period from time T4 to T5 (expected power transmission time) is approximately 18 msec. Note that, since a plurality of power supply devices 100 are installed at predetermined intervals on the power supply lane, vehicle 200 can be charged up to the requested power by each power supply device 100 performing the control shown in FIG. 4. Furthermore, when power supply is completed, the amount of power supplied up to that point is accumulated, and billing processing (billing processing) for that amount is executed.

[0050] In the above process, the vehicle 200 is shown traveling at a high speed (for example, 80 km / h), but similar control may be applied when traveling at a low speed or when the vehicle is stopped. That is, the process of this embodiment is widely applicable, for example, when the speed V1 of the vehicle 200 is 0 to 100 km / h. When the vehicle is stopped, power supply is controlled in consideration of a time rating, such as 1, 3, or 10 seconds, that is set in advance.

[0051] [Circuit configuration on the power transmission side and power receiving side] Next, the circuit configurations of the power transmitting side and the power receiving side will be described in detail. Fig. 5 is a diagram showing an example of the circuit configurations of the power transmitting side and the power receiving side according to the embodiment. Note that the example of Fig. 5 mainly specifically shows the circuit configuration of the transmission power conversion unit 114 in the power transmitting device 110 and the circuit configuration of the reception power conversion unit 212 in the power receiving device 210.

[0052] The transmission power conversion unit 114 includes an inverter that converts DC power to AC power. The inverter of the transmission power conversion unit 114 includes a bridge circuit formed by, for example, 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 made of silicon carbide (SiC). The plurality of switching elements are high-side arm and low-side arm transistors 114a and 114b that form a pair in each phase. The rectifying element is, for example, a freewheeling diode connected in parallel to each of the transistors 114a and 114b. A voltage-smoothing capacitor 114c is connected in parallel to the bridge circuit.

[0053] For example, the power transmitting side control unit 118 transmits power from the power transmitting device 110 via the power transmitting unit 116 by controlling the on (conduction) and off (cutoff) switching of each switching element of the power transmitting power conversion unit 114 according to the requested frequency from the power receiving device 210 side.

[0054] The receiving power conversion unit 212 includes, for example, a 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 made of SiC or the like. The plurality of switching elements are high-side arm and low-side arm transistors 212a, 212b that form a pair in each phase. The rectifying element is, for example, a freewheeling diode connected in parallel to each of the transistors 212a, 212b. A voltage smoothing capacitor 212c is connected in parallel to the bridge circuit. Note that in the embodiment, rectification may be performed using diodes instead of the transistors 212a, 212b.

[0055] For example, the vehicle-side control unit 215 receives power transmitted from the power transmitting device 110 via the power receiving unit 211 by controlling the on (conduction) and off (cutoff) switching of each switching element of the power receiving conversion unit 212 according to the required frequency.

[0056] 6 is a diagram showing an example of the circuit configuration of the power transmitting unit 116 and the power receiving unit 211. The power transmitting unit 116 includes a resonant circuit formed by, for example, a primary coil (Lt) 116a, a primary resistor (Rt) 116b, and a primary capacitor (resonant capacitor, Ct) 116c connected in series. The power transmitting unit 116 may also include various sensors, such as a current sensor that detects a current (power transmitting current) It flowing through the resonant circuit, and a voltage sensor that detects a voltage Vt.

[0057] The power receiving unit 211 includes, for example, a resonant circuit formed by a secondary coil (Lr) 211a, a secondary resistor (Rr) 211b, and a secondary capacitor (resonant capacitor, Cr) 211c connected in series. The primary capacitor 116c and the secondary capacitor 211c are, for example, capacitors for magnetic field resonance. The power receiving unit 211 may also include various sensors, such as a current sensor that detects a current (power receiving current) Ir flowing through the resonant circuit and a voltage sensor that detects a voltage Vt.

[0058] Incidentally, in conventional power control (power supply control) in contactless power transmission, power control is generally performed on the power transmitting side using pairing information. However, in contactless power supply while the vehicle 200 is traveling, the power receiving situation differs for each vehicle 200, so it is desirable to perform power control on the vehicle 200 side. Therefore, in the embodiment, a circuit (switching circuit) 211d that enables disconnection of the secondary-side capacitor (resonance capacitor) 211c according to predetermined conditions is implemented in the resonant circuit on the power receiving side, and the disconnection ratio (short mode ratio, described later) is adjusted according to the target power, thereby enabling more appropriate power receiving control on the power receiving side.

[0059] The switching circuit 211d is connected, for example, between the secondary coil 211a and the secondary capacitor 211c, which are connected in series. The switching circuit 211d shown in FIG. 6 is provided between the secondary resistor (Rr) 211b and the secondary capacitor 211c. The switching circuit 211d shown in FIG. 6 includes, for example, a bridge circuit formed by a plurality of switching elements and rectifying elements that are bridge-connected in two phases. Each switching element is, for example, a transistor made of SiC or the like. The rectifying element is, for example, a free wheel diode connected in parallel to each of the transistors 211d-1 to 211d-4. The switching circuit 211d is connected in parallel to the secondary capacitor 211c.

[0060] Vehicle-side control unit 215 receives power transmitted from power transmitting device 110 by controlling the on (conduction) and off (cutoff) switching of each of transistors 211d-1 to 211d-4. Vehicle-side control unit 215 also adjusts the amount of power received according to the target power by switching between a resonance mode in which secondary-side capacitor 211c is energized to resonate using the switching control described above, and a short mode in which secondary-side capacitor 211c is not energized and secondary-side coil 211a is short-circuited. Note that the short mode may also be referred to as a state in which resonance is not caused.

[0061] 7 is a diagram showing an example of the current flow in switching circuit 211d in resonance mode and short mode. In resonance mode, vehicle-side control unit 215 controls the switching of each of transistors 211d-1 to 211d-3 so that current from secondary-side resistor 211b passes through transistor 211d-3, capacitor 211c, and transistor 211d-2 of switching circuit 211d and flows to the receiving power conversion unit 212 side. In addition, in short mode, vehicle-side control unit 215 controls the switching of each of transistors 211d-1 to 211d-3 so that current from secondary-side resistor 211b passes through transistors 211d-4 and 211d-2 of switching circuit 211d and flows to the receiving power conversion unit 212 side. As a result, power is received in resonance mode and not in short mode, making it possible to adjust the power reception according to the target power.

[0062] In the embodiment, more appropriate power control can be achieved by providing switching circuit 211d on the power receiving device 210 side to adjust the current flowing through received power conversion unit 212. Also, in the embodiment, vehicle-side control unit 215 can receive more appropriate target power by adjusting the short mode ratio (duty ratio) for a predetermined time depending on the situation of vehicle 200.

[0063] 8 is a diagram illustrating a method for determining the short mode ratio. For example, vehicle-side control unit 215 derives an output value (an example of target power) that vehicle 200 can regenerate based on the SOC (an example of a power state) of power storage unit 214 mounted on vehicle 200, the temperature of power storage unit 214, and the supply voltage (an example of a power supply state) from power supply device 100. In this case, vehicle-side control unit 215 presets a three-dimensional regenerative output map with the SOC (State Of Charge), temperature, and supply voltage of power storage unit 214 as axes, and derives the regenerative output value based on the set map. In this map, for example, the higher the SOC of power storage unit 214, the closer the temperature is to a preset temperature suitable for regeneration, and the higher the supply voltage, the larger the regenerative output value that is output.

[0064] Furthermore, instead of the regenerative output map, vehicle-side control unit 215 may use a trained model that receives the SOC, temperature, and supply voltage of power storage unit 214 as input and outputs a regenerative output value corresponding to the input. The trained model is trained by an AI (Artificial Intelligence) function such as machine learning (neural network) or deep learning. Vehicle-side control unit 215 may acquire the trained model from an external source via vehicle-side communication unit 230, or the trained model may be stored in advance in a storage unit of vehicle 200.

[0065] Then, vehicle-side control unit 215 determines the short mode ratio based on the ratio between the derived regenerative output value and a received power value (predicted received power value) at a predetermined future time that is predicted in advance based on the status of vehicle 200. The predicted received power value may be predicted by vehicle-side control unit 215 based on an average value of the amount of received power in the past (a predetermined time up to immediately before), or may be a fixed value. For example, when a value α obtained by dividing the regenerative output value by the received power value is 1 or greater, vehicle-side control unit 215 does not perform the short mode (short mode ratio 0 [%]), and when α is less than 1, vehicle-side control unit 215 sets the short mode ratio to (1 - α) × 100 [%]. This makes it possible to more appropriately adjust the short mode according to the status of vehicle 200, and to adjust the amount of received power according to the target power. Note that the method for determining the short mode ratio is not limited to the above example, and may be appropriately adjusted based on, for example, the speed V1 of vehicle 200, the length of the power-receiving section, the performance of the power transmitting side and the power receiving side (power transmission performance), etc.

[0066] [Processing flow] FIG. 9 is a flowchart showing an example of a power transmission process in an embodiment. The process of FIG. 9 may be repeatedly executed at a predetermined timing. In the example of FIG. 9, vehicle-side control unit 215 acquires information on the SOC and temperature of power storage unit 214 and the supply voltage from power feeding device 100 (step S100), and derives a regenerative output value based on the acquired information (step S110). Next, vehicle-side control unit 215 adjusts the short mode ratio based on the regenerative output value and the predicted received power value (step S120). Next, vehicle-side control unit 215 executes switching control for switching circuit 211d between the short mode and the resonant mode based on the short mode ratio, and acquires the target power (step S130). This ends the process of this flowchart.

[0067] According to the embodiment described above, there is provided a contactless power transmission system 1 that contactlessly supplies power from a power supply device 100 installed on the path of a vehicle 200 (an example of a moving body) to a power receiving device 210 installed on the vehicle 200, wherein the power receiving device 210 includes a power receiving unit 211 that receives power through changes in the magnetic field transmitted from the power supply device by magnetic field coupling due to magnetic field resonance or electromagnetic induction, and a vehicle-side control unit 215 (an example of a control unit) that controls the power receiving unit 211, the power receiving unit 211 is connected between a coil and a resonant capacitor that are connected in series, and includes a switching circuit 211d that switches between a resonant mode in which current is passed through the resonant capacitor and a short mode in which current is not passed through the resonant capacitor, and the vehicle-side control unit 215 controls the switching circuit 211d to switch between modes according to predetermined conditions, thereby realizing more appropriate control of power transmission even when the vehicle 200 is moving.

[0068] Furthermore, according to the embodiment, by implementing a circuit (switching circuit) that disconnects the secondary-side capacitor (resonant capacitor, Cr) 211c on the power receiving device 210 side, it is possible to switch between a resonant state and a non-resonant state. Therefore, power adjustment is possible on the power receiving device 210 side, and power adjustment on the power supply device 100 side can be eliminated.

[0069] 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]

[0070] 1, 2... Contactless power transmission system, 100, 100A... Power supply device, 110... Power transmission device, 112... Power supply unit, 114... Transmission power conversion unit, 116... Power transmission unit, 118... Power transmission side control unit, 120... Communication control unit, 130... Power supply side communication unit, 200... Vehicle, 210... Power receiving device, 211... Power receiving unit, 212... Power reception power conversion unit, 213... Power conversion unit, 214... Power storage unit, 215... Vehicle side control unit, 220... Rotating electric machine, 230... Vehicle side communication unit, 240... Position information acquisition unit, 250... Camera, 260... Memory unit, 270... Recognition unit, 300... Information processing server

Claims

1. A contactless power transmission system that supplies power contactlessly from a power supply device installed on a path of a moving object to a power receiving device installed on the moving object, The power receiving device is a power receiving unit that receives power by a change in a magnetic field transmitted from the power supply device through magnetic field coupling; a control unit that controls the power receiving unit, the power receiving unit includes a switching circuit connected between the coil and the resonant capacitor connected in series, and configured to switch between a resonant mode in which current is passed through the resonant capacitor and a short mode in which current is not passed through the resonant capacitor; the control unit controls the switching circuit so that the mode is switched in accordance with a predetermined condition; the control unit determines the ratio of the short mode based on a ratio between a regenerative output value derived based on a power state of a power storage unit mounted on the mobile object, a temperature of the power storage unit, and a supply voltage from the power supply device, and a predicted future received power value. Contactless power transmission system.

2. The control unit adjusts the ratio of the short mode during a predetermined time period in accordance with a target power of the power receiving device. The contactless power transfer system according to claim 1 .

3. A mobile body equipped with a power receiving device that receives power contactlessly from a power supply device installed on a moving path, a power receiving unit that receives power by a change in a magnetic field transmitted from the power supply device through magnetic field coupling; a control unit that controls the power receiving unit, the power receiving unit includes a switching circuit connected between the coil and the resonant capacitor connected in series, and configured to switch between a resonant mode in which current is passed through the resonant capacitor and a short mode in which current is not passed through the resonant capacitor; the control unit controls the switching circuit so that the mode is switched in accordance with a predetermined condition; the control unit determines the ratio of the short mode based on a ratio between a regenerative output value derived based on a power state of a power storage unit mounted on the mobile object, a temperature of the power storage unit, and a supply voltage from the power supply device, and a predicted future received power value. Mobile object.

4. A contactless power transmission method for contactlessly supplying power from a power supply device installed on a path of a moving body to a power receiving device installed on the moving body, comprising: The power receiving device, receiving power from a change in a magnetic field transmitted from the power supply device by magnetic field coupling; a switching circuit connected between the coil and the resonant capacitor connected in series, for switching between a resonant mode in which the resonant capacitor is energized and a short mode in which the resonant capacitor is not energized, and for controlling the switching of the mode in accordance with predetermined conditions; determining the ratio of the short mode based on a ratio between a regenerative output value derived based on a power state of a power storage unit mounted on the mobile body, a temperature of the power storage unit, and a supply voltage from the power supply device, and a predicted future received power value; Contactless power transmission method.

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