Non-contact power transmission system, moving body, and non-contact power transmission method

Abstract

The invention provides a non-contact power transmission system, a moving object, and a non-contact power transmission method. In a non-contact power transmission system according to an embodiment of the present invention, power is supplied in a non-contact manner from a power supply device provided on a movement path of a moving body to a power receiving device provided on the moving body, the power receiving device comprising: a power receiving unit that receives power by means of a change in a magnetic field transmitted from the power supply device by means of magnetic field coupling; and a control unit that controls the power receiving unit, the power receiving unit being provided with a switching circuit that is connected between a coil and a resonance capacitor connected in series and that switches between a resonance mode in which the resonance capacitor is energized and a short-circuit mode in which the resonance capacitor is not energized, the control unit controlling the switching circuit. Therefore, the modes can be switched according to specified conditions.

Description

Technical Field

[0001] The present invention relates to a non-contact power transmission system, a mobile object, and a non-contact power transmission method. Background Art

[0002] In recent years, research and development related to charging and power supply in vehicles equipped with secondary batteries has been increasing, aiming to ensure convenient, reliable, sustainable, and advanced energy use, thereby contributing to energy efficiency. In this regard, a known technology is used in which, in a contactless power transmission system that supplies power from outside the vehicle to the vehicle, communication between the power transmitter and the power receiver is achieved by superimposing a communication signal on the power supply signal transmitted from the power transmitter to the power receiver (for example, see Japanese Patent Application Publication No. 2013-247807 and Japanese Patent No. 5348325). Summary of the Invention

[0003] Technologies related to charging and powering in vehicles equipped with secondary batteries have the following problem: while a mobile object such as a vehicle is moving, the distance between the power transmitting side and the power receiving side changes, sometimes preventing appropriate power transmission.

[0004] The present application aims to provide a non-contact power transmission system, a mobile body, and a non-contact power transmission method that can achieve more appropriate power transmission control even when the mobile body is moving. Furthermore, the present application contributes to energy efficiency.

[0005] A first embodiment of the present invention provides a contactless power transmission system for contactlessly supplying power from a power supply device provided on a moving path of a moving body to a power receiving device provided on the moving body, wherein the power receiving device comprises: a power receiving unit that receives power by utilizing changes in a magnetic field transmitted from the power supply device through magnetic field coupling; and a control unit that controls the power receiving unit, the power receiving unit comprising a switching circuit connected between a coil and a resonant capacitor connected in series to switch between a resonant mode in which power is supplied to the resonant capacitor and a short-circuit mode in which power is not supplied, and the control unit controls the switching circuit so as to switch the mode according to specified conditions.

[0006] According to a second aspect, in the contactless power transmission system according to the first aspect, the control unit may adjust the ratio of the short-circuit mode within a predetermined time period according to a target power of the power receiving device.

[0007] A third option, based on the contactless power transmission system of the first option, may be that the control unit determines the ratio of the short-circuit mode based on a ratio of a renewable output value to a predicted future received power value, wherein the renewable output value is 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 supplied from the power supply device.

[0008] A fourth aspect of the present invention is a moving object equipped with a power receiving device that receives power in a contactless manner from a power supply device provided on a moving path. The moving object includes: a power receiving unit that receives power by utilizing changes in a magnetic field transmitted from the power supply device through magnetic field coupling; and a control unit that controls the power receiving unit. The power receiving unit includes a switching circuit connected between a coil and a resonant capacitor connected in series to switch between a resonant mode in which power is supplied to the resonant capacitor and a short-circuit mode in which power is not supplied. The control unit controls the switching circuit so that the mode is switched according to predetermined conditions.

[0009] A fifth aspect of the present invention provides a contactless power transmission method for contactlessly supplying power from a power supply device located on a moving path of a moving body to a power receiving device located on the moving body, wherein the power receiving device receives power by utilizing changes in a magnetic field transmitted from the power supply device through magnetic field coupling; and controls a switching circuit connected between a series-connected coil and a resonant capacitor for switching between a resonant mode in which power is supplied to the resonant capacitor and a short-circuit mode in which no power is supplied, the switching circuit being controlled to switch between the two modes in accordance with prescribed conditions.

[0010] According to the first to fifth aspects, even when the mobile object is moving, more appropriate control of power transmission can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 1 is a schematic diagram of the configuration of a contactless power transmission system according to an embodiment.

[0012] Figure 2 It is a diagram showing an example of the configuration of a power supply device according to an embodiment.

[0013] Figure 3 This shows an example of the structure of the vehicle according to the embodiment.

[0014] Figure 4 A diagram for explaining transitions of operation modes.

[0015] Figure 5 This is a diagram showing an example of a circuit configuration on the power transmission side and the power reception side according to the embodiment.

[0016] Figure 6 This is a diagram showing an example of a circuit configuration of a power transmission unit and a power reception unit.

[0017] Figure 7 This is a diagram showing an example of the flow of current in the switching circuit in the resonance mode and the short-circuit mode.

[0018] Figure 8 This is a diagram for explaining a method for determining the short-circuit mode ratio.

[0019] Figure 9 This is a flowchart showing an example of power transmission processing in the embodiment. DETAILED DESCRIPTION

[0020] Hereinafter, a contactless power transmission system, a movable object, and a contactless power transmission method according to embodiments of the present invention will be described with reference to the accompanying drawings.

[0021] [System Structure]

[0022] Figure 1 This is a schematic diagram of the structure 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 as an example of a mobile object, and an information processing server 300. The power supply device 100 and the information processing server 300 communicate, for example, via a network NW. The network NW includes, for example, the Internet, a WAN (Wide Area Network), a LAN (Local Area Network), a cellular network, a public line, a supplier device, a wireless base station, and the like. It should be noted that in the contactless power transmission system 1, the vehicle 200 can also communicate with the information processing server 300 via the network NW using an onboard communication device. Furthermore, in the contactless power transmission system 1, the power supply device 100 and the vehicle 200 communicate using other communication methods described later. Furthermore, in the contactless power transmission system 1, the vehicle 200 is, for example, an electric vehicle such as an electric motor vehicle, a hybrid vehicle, or a fuel cell vehicle. It should be noted that, in addition to the vehicle 200, the mobile object according to the embodiment may also be an object capable of moving on a moving path, such as an electric robot. Furthermore, the mobile object may or may not carry a person. In addition, the mobile object may not only be manually driven by a passenger (driver) but may also have a structure capable of automatic driving.

[0023] The contactless power transmission system 1 supplies power from the power supply device 100 to the vehicle 200 through contactless power transmission between the power supply device 100 and the vehicle 200. It should be noted that in the contactless power transmission system 1, the power supply device 100 supplies power to multiple vehicles 200, and the vehicle 200 receives power from multiple power supply devices 100. However, for ease of explanation, the description focuses primarily on one-to-one contactless power supply.

[0024] The power supply device 100 is installed (buried) at predetermined intervals on a road surface (for example, lane L1) of a predetermined power supply lane (for example, lane L2) in lanes L1 and L2 (an example of a moving path) where the vehicle 200 can travel. Figure 1 The power supply devices 100-1, 100-2, 100-3, etc. shown in the figure).

[0025] The predetermined interval is, for example, an interval at which the magnetic field coupling regions between power supply devices 100 do not overlap. Furthermore, the predetermined interval may be set based on the type of road (e.g., general road, expressway), or may be set based on traffic regulations such as the road's speed limit. For example, power supply device 100 communicates with vehicle 200 approaching within a predetermined distance and supplies power in response to a power supply request from vehicle 200. Furthermore, power supply device 100 performs processing related to power control and power protection functions (e.g., FSA (Fail Safe Action)) in response to the request.

[0026] Vehicle 200 is equipped with a power receiving device 210. Power receiving device 210 is installed on the bottom of vehicle 200 to facilitate receiving power from a power supply device installed on the road, but the installation location is not limited to this. Power receiving device 210 performs processing related to vehicle energy management and power conservation functions (e.g., FSA). Vehicle 200 uses power stored in an onboard battery or other power storage unit to travel and supply power to other onboard equipment. While traveling on the powered lane (lane L1), vehicle 200 communicates with power supply devices 100-1 to 100-3, charging the power storage units installed in vehicle 200 using power supplied upon request. In the contactless power transmission system 1, the communication system required between power supply device 100 and vehicle 200 is a system that allows at least individual identification of vehicle 200 and enables communication while vehicle 200 is moving 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.

[0027] The information processing server 300 may be, for example, a server device, a PC (Personal Computer), or a cloud server formed by cloud computing composed of one or more information processing devices. The information processing server 300 communicates with the power supply device 100, the vehicle 200, etc. to perform various processes related to electricity. The information processing server 300 may be, for example, a charging system related to contactless power supply, an electricity quotation system, or a system that cooperates with these systems. The charging system is, for example, a system for individually identifying the vehicle 200 and charging a fee based on the charged electricity. The electricity quotation system performs, for example, various controls and management for providing low-cost electricity quotation based on demand forecasts.

[0028] The information processing server 300 also manages the status of the power supply device 100 , accumulates the power supplied from each power supply device 100 - 1 to 100 - 3 to the vehicle 200 , and calculates and manages the power actually transmitted to each vehicle 200 .

[0029] [Power supply device]

[0030] Figure 2 This is a diagram showing an example of the structure of a power supply device 100 according to an embodiment. The power supply device 100 includes, for example, a power transmission device 110, a communication control unit 120, and a power supply side communication unit 130. The power transmission device 110 includes, for example, a power supply unit 112, a power transmission power conversion unit 114, a power transmission unit 116, and a power transmission side control unit 118. Part or all of the power transmission side control unit 118 and the communication control unit 120 are implemented, for example, by a hardware processor such as a CPU (Central Processing Unit) executing a program (software). Part or all of these components may also 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 the collaboration of software and hardware. The program can be pre-stored in a storage device (a storage device with a non-temporary storage medium) such as the HDD (Hard Disk Drive) or flash memory of the power supply device 100, or it can be stored in a detachable storage medium such as a DVD or CD-ROM, and installed in the HDD or flash memory of the power supply device 100 by assembling the storage medium (non-temporary storage medium) in a drive device.

[0031] The power supply unit 112 of the power transmission device 110 is connected to the power transmission power conversion unit 114. The power supply unit 112 includes, for example, an AC power source such as a commercial power source, an AC-DC converter that converts the AC power into DC power, and capacitors for power smoothing. For example, the power supply unit 112 converts the AC power supplied from the AC power source into DC power using the AC-DC converter. Furthermore, the power supply unit 112 uses capacitors to smooth the power during power conversion.

[0032] The power transmission power conversion unit 114 is connected to the power transmission unit 116. The power 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 connected in a two-phase bridge, a rectifier element, and a resonant capacitor for adjusting the resonance of the coil. Details of the circuit configuration of the power transmission power conversion unit 114 will be described later.

[0033] Power transmission unit 116 transmits power to an external device (e.g., power receiving device 210 of vehicle 200) by utilizing changes in a high-frequency magnetic field, for example, through magnetic field coupling based on magnetic field resonance. In magnetic field resonance, for example, when current flows through a coil on the power transmission side, magnetic field vibrations are generated, which are then transmitted to a resonant circuit on the power reception side that resonates at the same frequency, thereby flowing current. Alternatively, magnetic field coupling can utilize known coupling methods such as electromagnetic induction. In electromagnetic induction, for example, power is transmitted using the induced magnetic flux generated between the power transmission and reception sides.

[0034] The power-transmitting-side control unit 118 comprehensively controls all functions of the power transmitting device 110 or the power supply device 100. For example, the power-transmitting-side control unit 118 controls pairing based on information (e.g., pairing signal, power-receiving-side operation mode) obtained through communication between the power-supplying-side communication unit 130 and the vehicle-side communication unit 230 of the vehicle 200. The pairing signal may include, for example, the power receiving device ID (identification information for power receiving device 210) or the vehicle ID (identification information for vehicle 200), parameter information such as the requested power, and battery voltage. For example, the power-transmitting-side control unit 118 identifies the power receiving device 210 and the vehicle 200 based on the power receiving device ID and the vehicle ID, and establishes (completes) pairing. Alternatively, the power-transmitting-side control unit 118 may reference user information pre-registered based on the power receiving device ID and the vehicle ID to establish pairing for users who are eligible for power supply (able to use the power supply service). The power-transmitting-side control unit 118 controls power transmission so that power is supplied to the paired vehicle 200.

[0035] The power receiving side operating mode refers to the operating mode of the power receiving device 210, described later, mounted on the vehicle 200. Examples include short-circuit mode, parameter transmission mode, standby mode, and power receiving mode. Short-circuit mode prevents unintended power reception and is used, for example, in FSA. Parameter transmission mode transmits parameter information. Standby mode, for example, waits for communication with the power supply side.

[0036] The power reception mode is a mode in which pairing is established, the power reception unit 211 and the received power conversion unit 212 are in operation and waiting for power reception, or in a state in which power reception is possible or in progress based on a predetermined frequency (required frequency for resonance).

[0037] In addition, the power transmission side control unit 118 controls the operation mode of the power transmission device 110 (power transmission side operation mode) according to the situation. Examples include a stop mode, a search (exploration) mode, a standby mode, and a power transmission mode. The stop mode in the power transmission side operation mode is a mode in which there is no vehicle providing service within the power transmission service area (electric road) and the vehicle is not operating. The search mode is a mode in which pairing with the vehicle 200 is established, the coupling coefficient is detected to increase, and the power transmission efficiency is ensured, and the power transmission is retained. The standby mode is, for example, a mode of waiting for communication with the power receiving side. The power transmission mode is, for example, a state in which power can be transmitted based on the required frequency or a state in which power is being transmitted (power transmission state).

[0038] For example, when pairing with vehicle 200 is established, the power transmitting-side control unit 118 changes the operating mode of the power transmitting device 110 from the stop mode to the receiving (standby) mode. Furthermore, upon receiving information such as the requested frequency for power transmission from the power receiving device 210 via the communication control unit 120, the power transmitting-side control unit 118 changes the power transmitting device 110 from the receiving mode to the search mode. Furthermore, when power transmission efficiency is maintained in the search mode, the power transmitting-side control unit 118 changes the mode to the power transmitting mode. Furthermore, in the power transmission state of the power transmitting mode, the power transmitting-side control unit 118 controls the on / off switching of each switching element of the power transmitting power converter 114 based on a preset drive frequency or information on the requested frequency (resonant frequency) received from the vehicle 200, thereby transmitting power to the power receiving device 210 of the vehicle 200. Furthermore, the power transmitting-side control unit 118 terminates pairing and shifts the power transmitting device 110 to the dormant state, for example, when power transmission to the vehicle 200 becomes impossible or when communication becomes impossible.

[0039] Furthermore, the power transmission-side control unit 118 also controls the charging and settlement of electricity used (kWh) after the system is used by the vehicle 200. The power transmission-side control unit 118 performs the aforementioned various controls based on various information obtained through communication between the power supply-side communication unit 130 and the vehicle-side communication unit 230.

[0040] The communication control unit 120 controls the operation of the power supply-side communication unit 130. For example, when there are multiple power supply-side communication units 130, the communication control unit 120 controls the operation of all power supply-side communication units 130. For example, the communication control unit 120 attempts to obtain specified information (e.g., pairing signals, information related to power transmission (e.g., required frequency, charges after system use, information required for settlement, 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 predetermined period or other timing. The communication control unit 120 outputs the obtained information to the power transmission-side control unit 118, or transmits information obtained from the power transmission-side control unit 118 (pairing establishment information, information required to start power transmission), etc. to the vehicle-side communication unit 230 via the power supply-side communication unit 130.

[0041] The power supply-side communication unit 130 is equipped with an antenna for wireless communication and other devices, and wirelessly communicates with external devices (e.g., information processing server 300, vehicle 200). Furthermore, the power supply-side communication unit 130 transmits and receives information related to power transmission from the power transmission device 110 to the vehicle 200. Specifically, the power supply-side communication unit 130 transmits and receives information for pairing with the vehicle 200, or for adjusting the amount of power to be transmitted, so that power is supplied to a specific vehicle 200 under the control of the power transmission-side control unit 118 and the communication control unit 120. Furthermore, the power supply-side communication unit 130 can also obtain information from other external devices via the network NW.

[0042] [vehicle]

[0043] Figure 3 2 is a diagram showing an example of the structure of a vehicle 200 according to the embodiment. The vehicle 200 includes, for example, a power receiving device 210, a rotating electrical machine 220, and a vehicle-side communication unit 230. Figure 3Although not shown, the vehicle 200 includes, for example, various devices (driving control devices, etc.) for driving on the road through manual or automatic driving by the passengers, as well as various on-board devices (loads, auxiliary devices) such as navigation devices and audio devices. The power receiving device 210 includes, for example, a power receiving unit 211, a power receiving 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 by, for example, a hardware processor such as a CPU executing a program (software). Some or all of these components can also be implemented by hardware (including circuitry) such as LSI, ASIC, FPGA, GPU, etc., or can be implemented through the collaboration of software and hardware. The program can be pre-stored in a storage device such as an HDD or flash memory of the vehicle 200 or the power receiving device 210 (a storage device having a non-transitory storage medium), or can 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 assembling the storage medium (non-transitory storage medium) in a drive device.

[0044] Power receiving unit 211 of power receiving device 210 is connected to received power converter 212. Power receiving unit 211 receives power by utilizing changes in the high-frequency magnetic field transmitted from power transmitting unit 116 through magnetic field coupling such as magnetic resonance or electromagnetic induction.

[0045] The receiving power converter 212 is connected to the power converter 213. The receiving power converter 212 converts, for example, AC power into DC power. For example, the receiving power converter 212 includes a bridge circuit formed by a plurality of switching elements and rectifier elements connected in a two-phase bridge, as well as capacitors for voltage smoothing. Details of the circuit configuration of the receiving power converter 212 will be described later.

[0046] For example, the power receiving device 210, which includes a power receiving unit 211 and a power receiving power conversion unit 212, controls the on-off switching of each switching element of the power receiving power conversion unit 212 based on information about the frequency of power transmission from the power transmitting device 110 under the control of the vehicle-side control unit 215, thereby receiving power transmitted from the power transmitting device 110.

[0047] 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 DC power into AC power. The power converter includes, for example, a component module and a capacitor for voltage smoothing. The component module includes, for example, a bridge circuit formed by multiple switching elements and rectifier elements connected in a three-phase bridge. The component module controls the operation of the rotating electric machine 220 by transferring power.

[0048] For example, during power operation of rotating electric machine 220, 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 rotating electric machine 220 from the three-phase AC terminals. The element module generates rotational driving force by sequentially rectifying the current flowing through the three-phase stator windings of rotating electric machine 220. Furthermore, during regeneration of rotating electric machine 220, the element module converts the three-phase AC power input from the three-phase stator windings into DC power by turning on and off the switching elements of each phase in synchronization with the rotation of rotating electric machine 220. The element module can supply the DC power converted from the three-phase AC power to power storage unit 214.

[0049] The rotating electric machine 220 is, for example, a three-phase AC brushless DC motor used to drive the vehicle. The rotating electric machine 220 includes a rotor with permanent magnets for excitation and a stator with three-phase stator windings that generate a rotating magnetic field to rotate the rotor. The three-phase stator windings are connected to the three-phase AC terminals of the power converter 213. The rotating electric machine 220 generates a rotational driving force by operating in a power-driven manner using the power supplied from the power converter 213. For example, when the rotating electric machine 220 is coupled to the wheels of the vehicle 200, it generates a driving force by operating in a power-driven manner using the power supplied from the power converter 213. The rotating electric machine 220 can also generate electric power by regenerating the rotational power input from the wheels of the vehicle 200. When the rotating electric machine 220 is coupled to the internal combustion engine of the vehicle 200, it can also generate electric power using the power of the internal combustion engine.

[0050] The power storage unit 214 includes, for example, a lithium-ion battery (an example of a secondary battery), a current sensor for detecting the battery's current, a voltage sensor for detecting the battery's voltage, and a temperature sensor for measuring the battery's temperature. The power storage unit 214 is connected to the power conversion unit 213 and the power receiving power conversion unit 212, described later. For example, the power storage unit 214, under the control of the vehicle-side control unit 215, receives power from the power supply device 100 or the rotating electric machine 220 and supplies the received power to the rotating electric machine 220 and various other onboard devices (loads, auxiliary equipment).

[0051] The vehicle-side control unit 215 comprehensively controls various functions of the power receiving device 210 or the entire vehicle 200. For example, the vehicle-side control unit 215 generates control signals indicating the timing for driving each switching element on (conducting) and off (disconnecting), and generates gate signals for actually driving each switching element on and off based on the control signals. For example, by controlling the switching of each switching element in the power receiving device 210, the vehicle-side control unit 215 rectifies the AC power received from the power transmitting device 110 into DC power, while also improving the power factor of the input voltage and input current.

[0052] The vehicle-side control unit 215 also generates specified information (e.g., pairing signals and information related to power transmission) for power transmission from the power supply device 100 and transmits the generated signal externally from the vehicle-side communication unit 230. It should be noted that the vehicle-side control unit 215 may transmit the pairing signal at a specified period or at other specified times. Furthermore, upon receiving permission information (pairing completion information) indicating that power supply is possible from the power supply device 100, as well as information required to start power transmission, from the vehicle-side communication unit 230, the vehicle-side control unit 215 obtains the target power by synchronously driving the multiple switching elements of the power receiving device 210 on and off, performing a synchronous rectification operation, or short-circuiting the secondary coil (described later). Furthermore, the vehicle-side control unit 215 controls the current flowing through the power transmitting device 110, thereby performing independent power control on the power receiving device 210, such as stopping power transmission.

[0053] Information related to power transmission includes, for example, the required power and frequency for power transmission, target output (power consumption) for failsafe, and information related to various abnormalities. The required power for power transmission is the target value of power that power receiving device 210 receives from power transmitting device 110. It is set based on, for example, the target driving force of vehicle 200 or rotating electric machine 220, the power consumption of various auxiliary machines connected to power storage unit 214, and the power state (SOC) of power storage unit 214. The power state includes, for example, the remaining capacity and charge rate of power storage unit 214. The required frequency for power transmission is the frequency required for power transmission by power transmitting device 110 and is set based on the required power. The required frequency is set based on, for example, the minimum ground clearance of vehicle 200 and the layout of power receiving device 210 in vehicle 200 to minimize reductions in power transmission efficiency and output (power). The required frequency can also be set based on, for example, the power transmission status between power transmitting device 110 and power receiving device 210. Furthermore, information related to power transmission may include information required for billing and settlement after system utilization.

[0054] Furthermore, the vehicle-side control unit 215 controls the operating mode of the power receiving device 210. These operating modes include, for example, short-circuit 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 operate to receive power through magnetic field coupling, such as magnetic field resonance or electromagnetic induction.

[0055] For example, the vehicle-side control unit 215 transmits a pairing signal at a predetermined interval, ranging from several tens of μs to several milliseconds. Upon receiving a response signal to the pairing signal from the power supply device 100, the vehicle-side control unit 215 changes the operating mode of the power receiving device 210 from the sleep mode to the power receiving mode, and begins controlling power transmission from the power supply device 100 during the power transmission interval. Furthermore, upon completion of power reception, the vehicle-side control unit 215 changes the operating mode of the power receiving device 210 from the power receiving mode to the standby mode.

[0056] The vehicle-side communication unit 230 is equipped with an antenna for wireless communication and other devices, and wirelessly communicates with external devices (e.g., the information processing server 300 and the power supply device 100). For example, the vehicle-side communication unit 230 transmits and receives information related to power transmission from the power supply device 100. Specifically, the vehicle-side communication unit 230 transmits and receives information for pairing with the power supply device 100, or for adjusting the amount of power transmitted, so that power can be supplied from a specific power supply device 100 under the control of the vehicle-side control unit 215. Furthermore, the vehicle-side communication unit 230 can also obtain information from other external devices via the network NW.

[0057] [About the transition of the operating mode during contactless power supply]

[0058] Next, transitions in the respective operating modes of the power transmitting device 110 and the power receiving device 210 during contactless power feeding will be described using the drawings. Figure 4 is a diagram for explaining the transition of the action mode. Figure 4 In the example, the horizontal axis represents time, and the vertical axis represents the operation of the vehicle 200, the operation mode (VA operation) of the power receiving device 210 side, and the operation mode (GA operation) of the power supply device 100. Figure 4 As an example of the action transition, an example of a case where contactless power transmission is performed between the power supply device 100 and the power receiving device 210 when the vehicle 200 is traveling at a predetermined speed (for example, about 80 [km / h]) is shown. The following describes the action transition accompanying the passage of time. It should be noted that Figure 4In the example, during contactless power supply, abnormality detection is always performed on the power receiving device 210 side and the power supply device 100 side. When an abnormality is detected, FSA (Fail Safe Action) (VA side FSA, GA side FSA) is executed to control to the safe side.

[0059] At time T1, the vehicle-side control unit 215 of the vehicle 200 communicates with the information processing server 300, for example, via the vehicle-side communication unit 230, to perform billing for contactless power supply or pre-processing (on-board device billing) for billing corresponding to the amount of power supplied. It should be noted that before time T1, the operating mode on the power receiving device 210 is in standby mode. Furthermore, during the billing process, the operating mode on the power supply device is in shutdown (OFF) mode.

[0060] At time T2, after the toll collection process is completed, power receiving device 210 positions vehicle 200 so that it passes over power supply device 100 installed on the road surface (e.g., a powered lane). In this case, an image showing the position of power supply device 100 (or the position of the powered lane) and the current position of vehicle 200 is displayed on a display unit (not shown) mounted on vehicle 200. The driver manually steers the vehicle while observing the image displayed on the display unit. Alternatively, if vehicle 200 includes a recognition unit (not shown) that uses images captured by an onboard camera or the like to identify the surrounding conditions of vehicle 200, and a driving control unit (not shown) that controls at least one of the steering and speed of vehicle 200 based on the surrounding conditions, the vehicle 200 can be positioned using control executed by the driving control unit. For example, if 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. Therefore, LKAS control can be used to control the vehicle 200 so that it travels in the powered lane, resulting in positioning. It should be noted that during the period from time T2 to time T3 , the power receiving device 210 remains in the short-circuited state, and the power supply device 100 transitions from the stop mode to the standby mode.

[0061] At time T3, when the distance between power receiving device 210 and power supply device 100 decreases to within a predetermined distance (a distance capable of communication) due to vehicle 200's travel, vehicle-side control unit 215 of vehicle 200 initiates pairing based on communication (VA-GA communication) between power receiving device 210 and power supply device 100. From time T3 to T4, vehicle-side control unit 215 repeatedly performs a transmission mode (transmitting parameter information (ID, required power, battery voltage, etc.)) and a standby mode until the power transmission efficiency exceeds a predetermined value (e.g., greater than 0%). Meanwhile, power transmission control unit 118 of power supply device 100 repeatedly performs a reception mode and a search mode. In search mode, for example, the efficiency is determined based on the correspondence information between power (transmitted power) and efficiency for power transmission according to horizontal distance (relative movement between the primary and secondary coils in a direction parallel to the road surface) in the contactless power transmission system 1 according to a predetermined embodiment, using the correspondence information. Furthermore, power transmission control unit 118 performs an efficiency assessment based on the voltage-to-current ratio. If the ratio is below a specified value, it outputs information to that effect to power receiving device 210, initiating a retry. In other words, in this embodiment, even when the transmission efficiency is unsuitable for power supply, communication related to the pairing described above can be performed. For example, if vehicle 200 is traveling at 80 km / h, the assumed period from time T3 to T4 (the assumed communication completion time) is approximately 22.5 msec.

[0062] At time T4, the efficiency of power transmission becomes greater than a specified value, so power transmission control is performed. For example, on the power supply device 100 side, power control (GA power control) is performed to transmit power corresponding to the required power specified by the parameter to the outside. In addition, on the power receiving device 210 side, power control (VA charging (power reception) control) is performed 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, when the power transmission efficiency between the power supply device 100 and the power receiving device 210 is below the specified value, the power supply device 100 communicates with the power receiving device 210 (pairing communication), and when the efficiency becomes greater than the specified value, the power supply control to the power receiving device 210 is performed. As a result, when the power transmission efficiency is poor, pairing communication can be completed in advance, and when the power transmission efficiency is good, power supply can be performed more efficiently.

[0063] At time T5, the power transmission efficiency becomes less than the specified value, so the power supply operation is terminated at this time point. Thus, power supply control using effective power transmission can be performed. For example, when the vehicle 200 is traveling at 80 [km / h], the assumed period from time T4 to T5 (the assumed power transmission time) is about 18 [msec]. It should be noted that since a plurality of power supply devices 100 are provided at specified intervals on the power supply lane, the power supply is performed by each power supply device 100. Figure 4 The control shown above allows the vehicle 200 to be charged to the required power. When the power supply is completed, the power amount accumulated so far is accumulated, and the corresponding request processing (billing processing) is executed.

[0064] It should be noted that while the above processing illustrates a case where vehicle 200 is traveling at a high speed (e.g., 80 km / h), similar control can be applied at lower speeds or when the vehicle is parked. That is, the processing of this embodiment is broadly applicable, for example, in scenarios where vehicle 200 has a speed V1 between 0 and 100 km / h. Regarding power supply during a parked state, power control is performed based on a preset rated time, such as 1, 3, or 10 seconds.

[0065] [Circuit Configurations on the Power Transmitting and Receiving Sides]

[0066] Next, the circuit configurations on the power transmission side and the power reception side will be described in detail. Figure 5 This is a diagram showing an example of the circuit configuration of the power transmission side and the power reception side of the embodiment. Figure 5 In the example of FIG. 1 , the circuit configuration of the transmission power conversion unit 114 in the power transmission device 110 and the circuit configuration of the reception power conversion unit 212 in the power reception device 210 are mainly specifically shown.

[0067] The power transmission power conversion unit 114 includes an inverter that converts DC power into AC power. The inverter of the power transmission power conversion unit 114 includes, for example, a bridge circuit formed by multiple switching elements and rectifier elements connected in a two-phase bridge, and a capacitor for voltage smoothing. Each switching element is, for example, a transistor made of SiC (Silicon Carbide). The multiple switching elements are transistors 114a and 114b, each forming a pair of high-side and low-side arms for each phase. The rectifier elements are, for example, freewheeling diodes connected in parallel with each transistor 114a and 114b. A capacitor 114c for voltage smoothing is connected in parallel with the bridge circuit.

[0068] For example, the power transmission side control unit 118 controls the switching of each switching element of the power transmission power conversion unit 114 to be turned on (conductive) and off (disconnected) according to the requested frequency from the power receiving device 210 , thereby transmitting power from the power transmission device 110 via the power transmission unit 116 .

[0069] The receiving power conversion unit 212 includes, for example, a bridge circuit formed by multiple switching elements and rectifier elements connected in a two-phase bridge, and a capacitor for voltage smoothing. Each switching element is, for example, a transistor made of SiC or the like. The multiple switching elements are transistors 212a and 212b, each forming a pair of high-side and low-side arms for each phase. The rectifier elements are, for example, freewheeling diodes connected in parallel with each transistor 212a and 212b. A capacitor 212c for voltage smoothing is connected in parallel with the bridge circuit. It should be noted that in the embodiments, diodes may be used for rectification instead of transistors 212a and 212b.

[0070] For example, the vehicle-side control unit 215 controls the switching of each switching element of the receiving power conversion unit 212 to be turned on (conductive) and off (disconnected) according to the required frequency, thereby receiving power transmitted from the power transmission device 110 via the power reception unit 211 .

[0071] Figure 6 This diagram shows an example of the circuit configuration of the power transmission unit 116 and the power reception unit 211. The power transmission unit 116 includes, for example, a resonant circuit formed by a primary-side coil (Lt) 116a, a primary-side resistor (Rt) 116b, and a primary-side capacitor (resonant capacitor, Ct) 116c connected in series. Furthermore, the power transmission unit 116 may include various sensors, such as a current sensor for detecting the current (transmission-side current) It flowing through the resonant circuit and a voltage sensor for detecting the voltage Vt.

[0072] The power receiving unit 211 includes, for example, a resonant circuit formed by a secondary-side coil (Lr) 211a, a secondary-side resistor (Rr) 211b, and a secondary-side capacitor (resonant capacitor, Cr) 211c connected in series. The primary-side capacitor 116c and the secondary-side capacitor 211c are, for example, magnetic field resonance capacitors. Furthermore, the power receiving unit 211 may include various sensors, such as a current sensor for detecting the current (receiving-side current) Ir flowing through the resonant circuit and a voltage sensor for detecting the voltage Vr.

[0073] However, conventional power control (power supply control) in contactless power transmission typically involves power control on the power transmitting side using pairing information. However, during contactless power supply while vehicle 200 is in motion, the power receiving conditions vary for each vehicle 200, making it desirable to be able to control power on the vehicle 200 side. Therefore, in the embodiment, a circuit (switching circuit) 211d is incorporated into the resonant circuit on the power receiving side, enabling disconnection of the secondary-side capacitor (resonant capacitor) 211c under specified conditions. By adjusting the disconnection ratio (the short-circuit mode ratio described below) based on the target power, more appropriate power reception control on the power receiving side is achieved.

[0074] The switching circuit 211 d is connected, for example, between the secondary-side coil 211 a and the secondary-side capacitor 211 c connected in series. Figure 6 The illustrated switching circuit 211 d is provided between the secondary-side resistor (Rr) 211 b and the secondary-side capacitor 211 c . Figure 6 The switching circuit 211d shown includes, for example, a bridge circuit formed by a plurality of switching elements and rectifier elements connected in a two-phase bridge. Each switching element is, for example, a SiC transistor. The rectifier element is, for example, a freewheeling diode connected in parallel with each of the transistors 211d-1 to 211d-4. The switching circuit 211d is connected in parallel with the secondary-side capacitor 211c.

[0075] The vehicle-side control unit 215 receives power from the power transmission device 110 by controlling the on / off switching of each transistor 211d-1 to 211d-4. Furthermore, the vehicle-side control unit 215 uses this switching control to switch between a resonant mode, in which power is supplied to the secondary-side capacitor 211c to cause resonance, and a short-circuit mode, in which power is not supplied to the secondary-side capacitor 211c and the secondary-side coil 211a is short-circuited. This adjusts the amount of power received according to the target power. Note that the short-circuit mode can also be referred to as a non-resonant state.

[0076] Figure 7 This diagram shows an example of the current flow within switching circuit 211d during resonance mode and short-circuit mode. In resonance mode, vehicle-side control unit 215 performs switching control of transistors 211d-1 to 211d-4 so that the current from secondary-side resistor 211b flows toward receiving power conversion unit 212 via transistor 211d-3, capacitor 211c, and transistor 211d-2 of switching circuit 211d. Furthermore, in short-circuit mode, vehicle-side control unit 215 performs switching control of transistors 211d-1 to 211d-4 so that the current from secondary-side resistor 211b flows toward receiving power conversion unit 212 via transistors 211d-4 and 211d-2 of switching circuit 211d. This allows power reception in resonance mode and non-power reception in short-circuit mode, enabling power reception to be adjusted to the target power.

[0077] In the embodiment, a switching circuit 211d is provided on the power receiving device 210 side to adjust the current flowing through the received power conversion unit 212, thereby achieving more appropriate power control. In addition, in the embodiment, the vehicle-side control unit 215 adjusts the short-circuit mode ratio (duty cycle) within a predetermined time period according to the condition of the vehicle 200, thereby enabling the reception of more appropriate target power.

[0078] Figure 8This is a diagram for explaining the method of determining the short-circuit mode ratio. For example, the vehicle-side control unit 215 derives the regenerative output value (an example of the target power) of the vehicle 200 based on the SOC (an example of the power state) of the storage unit 214 mounted on the vehicle 200, the temperature of the storage unit 214, and the supply voltage (an example of the power supply condition) supplied from the power supply device 100. In this case, the vehicle-side control unit 215 pre-sets a three-dimensional regenerative output map with the SOC (State Of Charge) of the storage unit 214, the temperature, and the supply voltage as the axes, and derives the regenerative output value based on the set map. In this map, for example, the greater the SOC of the storage unit 214, the closer the temperature is to the pre-set temperature suitable for regeneration, and the greater the supply voltage, the greater the regenerative output value output.

[0079] Alternatively, vehicle-side control unit 215 may use a learned model instead of the renewable output map. This learned model takes the SOC, temperature, and supply voltage of power storage unit 214 as input and outputs a renewable output value corresponding to the input. The learned model is learned, for example, using AI (artificial intelligence) functions such as machine learning (neural networks) or deep learning. Vehicle-side control unit 215 may also obtain the learned model from an external source via vehicle-side communication unit 230, or the learned model may be pre-stored in the storage unit of vehicle 200.

[0080] The vehicle-side control unit 215 then determines the short-circuit mode ratio based on the ratio of the derived renewable output value to the received power value (predicted received power value) predicted in advance for a predetermined future time period based on the vehicle 200's condition. The predicted received power value can be predicted by the vehicle-side control unit 215 based on the average value of the received power over the past (predicted time period up to the previous time period) or a fixed value. For example, if the value α, obtained by dividing the renewable output value by the received power value, is greater than 1, the vehicle-side control unit 215 does not perform the short-circuit mode (short-circuit mode ratio 0 [%]). If α is less than 1, the short-circuit mode ratio is set to (1-α) × 100 [%]. This allows the short-circuit mode to be more appropriately adjusted according to the vehicle 200's condition, allowing the received power amount to be adjusted to match the target power. It should be noted that the method for determining the short-circuit mode ratio is not limited to the example described above; for example, it can be appropriately adjusted based on the vehicle 200's speed V1, the length of the power-receivable section, the performance of the power transmission and reception sides (power transmission performance), and other factors.

[0081] [Processing Flow]

[0082] Figure 9 This is a flowchart showing an example of power transmission processing in the embodiment. Figure 9 The processing can be executed repeatedly at the specified timing. Figure 9 In the example shown in FIG. 1 , the vehicle-side control unit 215 obtains information regarding the SOC and temperature of the power storage unit 214, as well as the supply voltage from the power supply device 100 (step S100), and derives the renewable output value based on the obtained information (step S110). Next, the vehicle-side control unit 215 adjusts the short-circuit mode ratio based on the renewable output value and the predicted received power value (step S120). Next, the vehicle-side control unit 215 controls the switching circuit 211d to switch between short-circuit mode and resonant mode based on the short-circuit mode ratio to obtain the target power (step S130).

[0083] Thus, the processing of this flowchart ends.

[0084] According to the embodiment described above, in a contactless power transmission system 1 that supplies power in a contactless manner from a power supply device 100 installed on a moving path of a vehicle 200 (an example of a mobile object), power receiving device 210 installed on vehicle 200 includes a power receiving unit 211 that receives power by utilizing changes in a magnetic field transmitted from the power supply device through magnetic field coupling based on magnetic field resonance or electromagnetic induction; and a vehicle-side control unit 215 (an example of a control unit) that controls power receiving unit 211. Power receiving unit 211 includes a switching circuit 211d connected between a series-connected coil and a resonant capacitor to switch between a resonant mode in which power is supplied to the resonant capacitor and a short-circuit mode in which power is not supplied. The vehicle-side control unit 215 controls the switching circuit 211d so as to switch between the modes according to predetermined conditions. This allows for more appropriate control of power transmission even while vehicle 200 is moving.

[0085] Furthermore, according to the embodiment, a circuit (switching circuit) is incorporated on the power receiving device 210 side to disconnect the secondary-side capacitor (resonant capacitor, Cr) 211c, thereby enabling switching between a resonant state and a non-resonant state. This allows power adjustment on the power receiving device 210 side, eliminating the need for power adjustment on the power supply device 100 side.

[0086] The embodiments of the present invention are provided as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways and can be omitted, replaced, or modified without departing from the scope of the invention. These embodiments and their variations are included within the scope and spirit of the invention, and are also included in the invention described in the technical solutions and their equivalents.

Claims

1. A contactless power transmission system for supplying power in a contactless manner from a power supply device provided on a moving path of a moving object to a power receiving device provided on the moving object, wherein: The power receiving device comprises: a power receiving unit that receives power by utilizing a change in the magnetic field transmitted from the power supply device through magnetic field coupling; and a control unit that controls the power receiving unit, The power receiving unit includes a switching circuit connected between the series-connected coil and the resonant capacitor to switch between a resonant mode in which power is supplied to the resonant capacitor and a short-circuit mode in which power is not supplied. The control unit controls the switching circuit so as to switch the mode according to a predetermined condition.

2. The contactless power transmission system according to claim 1, wherein: The control unit adjusts the ratio of the short-circuit mode within a predetermined time period according to target power of the power receiving device.

3. The contactless power transmission system according to claim 1, wherein: The control unit determines the ratio of the short-circuit mode based on a ratio of a renewable 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 supplied from the power supply device, to a predicted future received power value.

4. A mobile body equipped with a power receiving device that receives power from a power supply device provided on a moving path in a contactless manner, wherein: The mobile body comprises: a power receiving unit that receives power by utilizing a change in the magnetic field transmitted from the power supply device through magnetic field coupling; and a control unit that controls the power receiving unit, The power receiving unit includes a switching circuit connected between the series-connected coil and the resonant capacitor to switch between a resonant mode in which power is supplied to the resonant capacitor and a short-circuit mode in which power is not supplied. The control unit controls the switching circuit so as to switch the mode according to a predetermined condition.

5. A contactless power transmission method for supplying power in a contactless manner from a power supply device provided on a moving path of a moving body to a power receiving device provided on the moving body, wherein: The power receiving device performs the following processing: receiving electric power by utilizing a change in the magnetic field transmitted from the power supply device through magnetic field coupling; and A switching circuit connected between the series-connected coil and the resonant capacitor for switching between a resonant mode in which power is supplied to the resonant capacitor and a short-circuit mode in which power is not supplied is controlled to switch the mode in accordance with predetermined conditions.

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