Wireless power transmission systems, power transmission modules

Abstract

This invention provides a technology that can improve the charging speed in microwave-based wireless power transmission systems. [Solution] The wireless power transmission system comprises a plurality of power transmission modules and a controller. The plurality of power transmission modules include a first module and a second module, each located in different positions. The controller 1 simultaneously drives the first module and the second module to attempt to charge the powered device for a predetermined time. Based on the amount of power received by the powered device during this attempt, the controller 1 determines whether it is necessary to change the transmission settings of the second module. If sufficient power supply is achieved, the current settings are maintained. On the other hand, if the received power is insufficient, the transmission settings of the second module (e.g., phase or frequency) are shifted by a predetermined amount.

Description

Technical Field

[0001] This disclosure relates to a technology for wirelessly transmitting power to a device.

Background Art

[0002] Patent Document 1 discloses a wireless power transmission system using the microwave method, which includes a plurality of power transmission antennas for wirelessly transmitting power. The control unit constituting the wireless power transmission system estimates the position of the target device based on the reception intensity of the signal transmitted from the target device, and performs wireless charging by selectively using the power transmission antenna corresponding to the estimated position.

[0003] Here, the target device means a device to be charged. The microwave method can be understood as a method of charging a device separated by 0.5 m or more by transmitting radio waves at frequencies of 900 MHz or higher, such as 920 MHz, 2.4 GHz, or 5.7 GHz. The microwave method can also be called the radio wave power reception method, the space transmission method, the radiation type charging method, BEAM WPT, etc. In addition, as wireless power transmission technologies other than the microwave method, there are non-radiative wireless power transmission technologies (also called NON-BEAM WPT) such as the electromagnetic induction method, the magnetic field resonance method, or the electric field coupling method.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Microwave wireless charging is less efficient than non-radiative wireless charging. Existing methods have slow charging speeds and may not adequately charge the receiving device. To address this issue, the developers of this disclosure considered increasing the charging speed by driving two or more power transmission modules in parallel. However, when multiple power transmission modules operate in parallel, the charging radio waves transmitted by each module may cancel each other out, potentially reducing the charging speed.

[0006] This disclosure is based on the above considerations and one of its purposes is to improve the charging speed in microwave wireless power transmission systems. [Means for solving the problem]

[0007] One of the wireless power transmission systems disclosed herein is a wireless power transmission system for wirelessly charging a power receiving device in a target space, comprising: a plurality of power transmission modules (2) configured to transmit charging radio waves, which are radio waves for charging; and a control unit (1) for controlling the plurality of power transmission modules, wherein the plurality of power transmission modules include a first power transmission module and a second power transmission module, and the control unit is configured to wirelessly communicate data with the power receiving device using one of the plurality of power transmission modules or other communication modules. The control unit is configured to drive the first power transmission module and the second power transmission module in parallel, and to adjust the transmission settings for the charging radio waves in the second power transmission module by communicating data with the power receiving device.

[0008] According to the above configuration, the transmission settings (e.g., phase, frequency, etc.) of the charging radio waves in the second power transmission module are adjusted through communication with the power receiving device. This reduces the risk that the charging radio waves transmitted by the first power transmission module and the charging radio waves transmitted by the second power transmission module will continuously cancel each other out. Furthermore, by adjusting the settings, it is also possible to make the charging radio waves transmitted by the first power transmission module and the charging radio waves transmitted by the second power transmission module reinforce each other. This improves the charging speed in a microwave-type wireless power transmission system.

[0009] The power transmission module included in this disclosure is a power transmission module for wirelessly charging a power receiving device in a target space, and comprises an antenna (21) configured to transmit charging radio waves, which are radio waves for charging; a power transmission circuit (22) for transmitting charging radio waves from the antenna; a communication circuit (23) for communicating with a controller that controls wireless charging of the power receiving device; and a wireless control unit (24) for controlling the power transmission circuit based on data received from the controller via the communication circuit. The wireless control unit is configured to perform data communication with the power receiving device via the antenna, and is configured to transmit charging radio waves from the antenna using the power transmission circuit based on instructions from the controller, receive feedback data indicating received power transmitted from the power receiving device and provide it to the controller, and adjust the transmission settings of the charging radio waves based on signals input from the controller.

[0010] The above-mentioned power transmission module is a power transmission module for realizing one form of the aforementioned wireless power transmission system. By working in cooperation with other power transmission modules and controllers, this power transmission module can improve the charging speed in a microwave-based wireless power transmission system.

[0011] The reference numerals in parentheses in the claims indicate the correspondence with the specific means described later in the embodiments, and do not limit the technical scope of this disclosure. [Brief explanation of the drawing]

[0012] [Figure 1] It is a block diagram showing the configuration of a wireless power transmission system. [Figure 2] It is a block diagram showing the configuration of a power receiving device. [Figure 3] It is a diagram showing an example of the installation position of a power transmission module. [Figure 4] It is a block diagram showing the configuration of a power transmission module. [Figure 5] It is a diagram showing an example of an occupant sensor. [Figure 6] It is a block diagram showing the configuration of a controller. [Figure 7] It is a diagram showing an example of the procedure of ranging communication. [Figure 8] It is a flowchart of charging processing. [Figure 9] It is a flowchart showing another operation example of the controller. [Figure 10] It is a flowchart showing another operation example of the controller. [Figure 11] It is a flowchart showing an example of the flow of normal power transmission control. [Figure 12] It is a diagram for explaining the interference of a plurality of charging radio waves. [Figure 13] It is a diagram for explaining the interference of a plurality of charging radio waves. [Figure 14] It is a flowchart of adjustment processing. [Figure 15] It is a diagram showing the interaction between devices in adjustment processing. [Figure 16] It is a flowchart showing another example of adjustment processing. [Figure 17] It is a diagram for explaining the effect by frequency change.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments. The configurations disclosed below may be variously modified and implemented without departing from the gist. Various modifications may be appropriately combined and implemented within a range where no technical contradiction occurs. The present disclosure also includes configurations that are not explicitly stated, which are combinations of a plurality of modifications. In the following description, members having the same function may be denoted by the same reference numerals, and their specific descriptions may be omitted. Also, members having the same function may be given the same or similar names, and their specific descriptions may be omitted. When only a part of the configuration is mentioned, the descriptions given elsewhere may be applied to the other parts.

[0014] One embodiment of the wireless power transmission system 100 according to the present disclosure will be described below with reference to the drawings. FIG. 1 is a diagram showing an example of a schematic configuration of the wireless power transmission system 100. As shown in FIG. 1, the wireless power transmission system 100 is mounted on a vehicle Hv. The wireless power transmission system 100 includes a controller 1, a plurality of power transmission modules 2, an occupant sensor 3, and an information presentation device 4.

[0015] The wireless power transmission system 100 is configured to be able to wirelessly charge a power receiving device 9 in the vehicle by a microwave method. In FIG. 1, only one power receiving device 9 is shown, but there may be a plurality of power receiving devices 9 in the vehicle. Among the plurality of power receiving devices 9, the device to be charged is hereinafter also referred to as the charging target or target device. Information (for example, device ID) of the power receiving device 9 is registered in advance in the controller 1 of the wireless power transmission system 100. The power receiving device 9 may be regarded as a communication device that is registered in advance in the wireless power transmission system 100 as a key of the vehicle Hv.

[0016] <Power Receiving Device> The power receiving device 9 may be a personal device. A personal device is a device brought in by the occupants of the hybrid vehicle (HV). The power receiving device 9 as a personal device may be a smartphone, tablet, laptop, vehicle key, wearable device, or mobile battery. The vehicle key here refers to a dedicated communication device that serves as the electronic key for the HV. The vehicle key may be transferred to the owner along with the HV at the time of purchase. The vehicle key may also be called a smart key, vehicle portable device, key fob, key card, access key, etc.

[0017] The power receiving device 9 may be a fixed device installed inside the vehicle. For example, the power receiving device 9 as a fixed device may be a dashcam, speaker, air purifier, decorative light, or exterior display. The power receiving device 9 may also be a device that can be attached and detached by the user.

[0018] The power receiving device 9 is configured to enable short-range communication with the power transmitting module 2 according to a predetermined communication protocol. Short-range communication is a communication method that conforms to a predetermined short-range wireless communication standard, with an effective communication range of 1m to 30m, and a maximum of approximately 100m. In this embodiment, the short-range communication method is BLUETOOTH® Low Energy (hereinafter referred to as BLUETOOTH LE). Communication conforming to the BLUETOOTH LE standard will also be referred to as LE communication below. Hereafter, LE signal refers to a communication packet transmitted and received via LE communication. The terms short-range communication and LE communication may be replaced with SRWC (Short Range Wireless Communication). LE signal may be replaced with SRWC signal.

[0019] The LE signal contains information indicating the source or destination. The source and destination of the LE signal may be represented, for example, by a device ID. The device ID is a number used to identify a device. One of the multiple power transmission modules 2 may be pre-paired with a power receiving device 9 and each may hold its own device ID.

[0020] The power transmission module 2 and the power receiving device 9 are configured to perform distance measurement communication using LE signals in addition to data communication. Distance measurement communication is a type of communication that measures the distance between communication devices. Details of distance measurement communication will be described separately.

[0021] As shown in Figure 2, the power receiving device 9 comprises a device controller 91, a battery 92, and an LE module 93. The device controller 91 is configured to control the operation of the LE module 93. The device controller 91 is configured as a computer, including a processor, memory, storage, and input / output circuits. The battery 92 may be any type of secondary battery, such as a lithium-ion secondary battery, a lithium-ion polymer secondary battery, a nickel-cadmium battery, or a nickel-metal hydride rechargeable battery.

[0022] The LE module 93 is a communication module for LE communication provided on the power receiving device 9. The LE module 93 may include an antenna, a power receiving circuit 931, and a radio control unit. The antenna is an antenna element for transmitting and receiving radio waves in the frequency band used for LE communication (e.g., the 2.4 GHz band). The power receiving circuit 931 is a circuit that converts the power received by the antenna into a DC voltage suitable for charging the battery 92 and outputs it to the battery 92. The power receiving circuit 931 may be implemented using a rectifier circuit and a converter, etc.

[0023] The wireless control unit is a circuit module that performs processing related to the transmission and reception of wireless signals. The wireless control unit demodulates the signal received by the antenna and provides it to the device controller 91. The wireless control unit also modulates the transmission data input from the device controller 91 and radiates it as radio waves from the antenna. The wireless control unit may include a local oscillator, a VCO (Voltage-controlled oscillator), a mixer, a phase shifter, an amplifier, a filter, etc. The wireless control unit may include ICs for modulation and demodulation, and a microcontroller unit (MCU) for data processing.

[0024] The LE module 93 is configured to transmit and receive continuous wave signals for each channel using an antenna, in addition to modulated signals for data communication, as well as for CS (Channel Sounding) ranging, as described later. The continuous wave signal is also referred to as the (CW: Continuous Wave) signal below. The waveform of the CW signal may be a sine wave. The CW signal used for CS ranging may also be called a tone. The CW signal corresponds to the ranging signal. The CW signal can also function as a charging radio wave.

[0025] The radio control unit has a function to detect the strength and phase of the received signal. When the radio control unit receives a CW signal, it detects the received phase, which is the phase angle of the received CW signal relative to the output signal of the local oscillator. For example, the radio control unit identifies the received phase and received strength by analyzing the IQ signal. Received strength is a parameter also expressed as RSSI (Received Signal Strength Indicator / Indication). The radio control unit stores the received phase and received strength of the received CW signal in memory, associating them with information indicating the frequency of the CW signal (e.g., channel number).

[0026] The LE module 93 (and by extension, the radio control unit) may have the following operating modes: data communication mode, CS ranging mode, and radio power reception mode. The data communication mode is a mode that enables normal data communication. The CS ranging mode is a mode that transmits or receives CW signals. The radio power reception mode is a mode that supplies radio power received by the antenna to the battery 92. The LE module 93 may also be configured to charge the battery 92 using the power of signals for ranging or data communication. The radio power reception mode, which is for power reception only, may be omitted.

[0027] The wireless control unit may switch from data communication mode or CS distance measurement mode to wireless power reception mode based on instructions from the device controller 91. The wireless control unit may switch from wireless power reception mode to data communication mode or CS distance measurement mode based on instructions from the device controller 91.

[0028] Furthermore, the wireless control unit switches from data communication mode to CS ranging mode based on instructions from, for example, the device controller 91, and transmits or receives CW signals while switching the channel used at predetermined intervals. The wireless control unit may also detect the received strength of not only CW signals but also normal LE signals (e.g., advertised / data packets) and output it to the MCU.

[0029] The MCU in the wireless control unit may have a function to calculate the distance measurement value based on the received phase for each channel observed by CS ranging. The MCU can transmit data indicating the measured received strength along with source information to the device controller 91.

[0030] The LE module 93 transmits and receives LE signals under the control of the device controller 91. For example, if the powered device 9 is not communicating with the DK-ECU2, the device controller 91 uses the LE module 93 to periodically advertise in the LE. Advertising is the process of transmitting an advertisement signal using a predetermined channel. When the wireless power transmission system 100 receives an advertisement signal from the powered device 9, it may send a connection request in response. When the device controller 91 receives a connection request from the DK-ECU2, it establishes a communication connection between the LE module 93 and the wireless power transmission system 100.

[0031] <Power transmission module> The wireless power transmission system 100 comprises multiple power transmission modules 2. All of the power transmission modules 2 are connected to a controller 1. The multiple power transmission modules 2 are distributed throughout the vehicle. Here, "vehicle interior" refers to the interior space of the vehicle, which may be the so-called cabin. The vehicle interior may also include the trunk space. The vehicle interior corresponds to the target space. Although only two power transmission modules 2 are shown in Figure 1, the wireless power transmission system 100 may have three or more power transmission modules 2.

[0032] In this embodiment, as an example, the multiple power transmission modules 2 include a first module 2A, a second module 2B, a third module 2C, a fourth module 2D, and a fifth module 2E, as shown in Figure 3. The first module 2A, the second module 2B, the third module 2C, and the fourth module 2D are located at the four corners of the vehicle interior. For example, the first module 2A is located near the upper end of the right A-pillar. The second module 2B is located near the right C-pillar. The third module 2C is located near the left C-pillar. The fourth module 2D is located near the upper end of the left A-pillar. The fifth module 2E may be located in the center of the ceiling. Each of the multiple power transmission modules 2 is assigned a unique module number. The module numbers may be used by the controller 1 to control and manage the multiple power transmission modules 2.

[0033] Each of the multiple power transmission modules 2, as shown in Figure 4, includes multiple antennas 21, a power transmission circuit 22, a communication circuit 23, and a wireless control unit 24. The functions and configurations of the multiple power transmission modules 2 are generally identical. In other embodiments, there may be individual differences between the power transmission modules 2. For example, the antenna directivity, antenna type, and number of antennas may differ for each power transmission module 2.

[0034] The power transmission module 2 may have a configuration that is generally the same as that of the LE module 93. However, the configuration related to power transmission / reception may differ. The power transmission module 2 may have a configuration that corresponds to that of the LE module 93. The description of each part of the power transmission module 2 may be applied or taken into consideration as necessary. Also, the description of the power transmission module 2 may be applied or taken into consideration as appropriate in the description of the LE module 93.

[0035] Antenna 21 is an antenna element for transmitting and receiving radio waves in the frequency band used for LE communication. Multiple antennas 21 are configured, for example, as a two-dimensional array antenna. The power transmission module 2 is configured to have variable directivity using multiple antennas 21. For example, the power transmission module 2 may have its directivity changed by adaptive array antenna technology. The directivity of the power transmission module 2 may be changed by digital beamforming or analog beamforming. The directivity of the power transmission module 2 is controlled by controller 1.

[0036] In other embodiments, the directivity of the power transmission module 2 may be adjusted mechanically using an actuator such as a motor. The directivity of the power transmission module 2 may also be changed by physically changing the orientation of the antenna 21. Furthermore, in a hardware configuration where multiple antennas 21 with different directivity are provided, the controller 1 may change the directivity of the power transmission module 2 by switching which antenna 21 is activated.

[0037] The power transmission circuit 22 is a circuit for transmitting charging radio waves from the antenna 21. The charging radio waves may be a CW signal with a predetermined fundamental frequency. The fundamental frequency may be the center frequency of the frequency band used in LE communication. The charging radio waves may be an unmodulated signal. The setting of the fundamental frequency and initial phase to predetermined fundamental values ​​(e.g., 0) is also called the basic setting. The frequency used for charging is also called the charging frequency.

[0038] The power transmission circuit 22, under the control of the wireless control unit 24, generates a high-frequency electrical signal corresponding to the charging radio wave and inputs it to the antenna 21. The power transmission circuit 22 is configured to allow adjustment of the transmission power, phase, and frequency of the charging radio wave. Adjusting the transmission power corresponds to adjusting the amplitude or signal strength.

[0039] The communication circuit 23 is a circuit for the power transmission module 2 (particularly the wireless control unit 24) to communicate with the controller 1. The communication circuit 23 provides data input from the controller 1 to the wireless control unit 24 and transmits data input from the wireless control unit 24 to the controller 1. The communication circuit 23 may also have modulation / demodulation functions depending on the communication method between the power transmission module 2 and the controller 1.

[0040] The wireless control unit 24 is a circuit module that performs processing related to the transmission and reception of wireless signals. The wireless control unit includes an IC 231 for modulation and demodulation, and an MCU 232 for data processing. For example, IC 231 demodulates the signal received by antenna 21 and provides it to MCU 232. MCU 232 modulates the transmission data input from controller 1 and radiates it as radio waves from the antenna. In addition to IC 231 and MCU 232, the wireless control unit 24 may include a local oscillator, a VCO (Voltage-controlled oscillator), a mixer, a phase shifter, an amplifier, a filter, and the like.

[0041] The wireless control unit 24 has a function to detect the strength and reception phase of the signal received in the distance measurement communication. The configuration of the power transmission module 2 related to the distance measurement communication may be the same as that of the LE module 93. The power transmission module 2 can calculate the distance measurement value based on the phase information for each channel observed in the CS distance measurement and transmit it to the controller 1.

[0042] The power transmission module 2 may have three operating modes: a data communication mode, a CS distance measurement mode, and a wireless power transmission mode. The wireless power transmission mode is a mode in which charging radio waves are transmitted. The power transmission module 2 may be configured to switch operating modes based on instructions from, for example, the controller 1. Alternatively, the operating mode of the power transmission module 2 may be changed spontaneously based on the judgment of the wireless control unit 24. Transmitting charging radio waves is equivalent to wirelessly transmitting power.

[0043] <Occupant Sensor> The occupant sensor 3 is connected to the controller 1. The occupant sensor 3 is a sensor that outputs data signals indicating the presence or absence of occupants inside the vehicle, and, if present, their location. An occupant is a person who uses the vehicle Hv, and may also be called a driver or user. If the vehicle Hv is a privately owned car (a so-called owner car), the occupant may be the owner of the vehicle Hv or a related party. If the vehicle Hv is a service vehicle such as a bus, the occupant may be a service user.

[0044] In this disclosure, information including the presence or absence of occupants, and if occupants are present, their location, is also referred to as occupant information. The occupant sensor 3 may be understood as a sensor for which the controller 1 acquires or generates occupant information. Since occupant information also represents information indicating the in-vehicle environment, it may also be referred to as environmental information. The occupant sensor 3 corresponds to a sensor associated with the target space.

[0045] The wireless power transmission system 100 may include, as shown in Figure 5, an occupant sensor 3, a UWB (Ultra Wide Band) radar 31, an in-vehicle camera 32, an infrared sensor 33, a seating sensor 34, and a seat belt sensor 35. The various occupant sensors 3 input data corresponding to the detection results to the controller 1. The wireless power transmission system 100 does not need to include all of the sensors exemplified here. The sensors included in the occupant sensor 3 may be only some of the following.

[0046] The UWB radar 31 is a radar that detects the position, speed, etc. of an object using an impulse wave used in UWB-IR (Impulse Radio) communication as a search wave. The impulse wave used in UWB communication may be a signal with a pulse width of very short time (for example, 2 ns) and a bandwidth of 500 MHz (strictly speaking, 499.2 MHz) or more. The UWB radar 31 may be configured to detect the position, posture, breathing, or intensity of movement of an occupant by analyzing reflected radio waves from the occupant. The UWB radar 31 may be a radar that constitutes an in-vehicle monitoring system. The in-vehicle monitoring system may be a system for detecting cases such as children being left unattended.

[0047] The wireless power transmission system 100 may also include, in place of or in addition to, the UWB radar 31, other types of radar, such as a MIMO (Multi Input Multi Output) millimeter-wave radar. The radar device for detecting the crew may be a radar device that uses 60 GHz band electromagnetic waves as search waves. The controller 1 may generate and update crew information based on the driving results of any type of radar.

[0048] The in-vehicle camera 32 is a visible light camera installed inside the vehicle so as to be able to capture images of the interior. There may be one or multiple in-vehicle cameras 32. The controller 1 may generate and update occupant information by analyzing the video signals input from the in-vehicle cameras 32.

[0049] The infrared sensor 33 measures infrared radiation emitted from the human body and, based on the measurement results, detects the number of people present in the monitored space (in this case, inside the vehicle), their positions (i.e., occupant positions), etc. One or more infrared sensors 33 may be installed inside the vehicle. The controller 1 may determine the presence and position of living organisms (primarily humans) inside the vehicle based on the data signals input from the infrared sensors 33 installed inside the vehicle. The controller 1 may generate or update occupant information using optical sensors instead of or in addition to the infrared sensors.

[0050] The seating sensor 34 is a sensor that detects whether or not an occupant is seated. The seating sensor may be a pressure sensor or a weight sensor embedded in the seating surface of the seat. A seating sensor 34 may be provided for each seat. The seat belt sensor 35 is a sensor that outputs a signal indicating the seat belt fastening status. A seat belt sensor 35 may also be provided for each seat. The controller 1 may determine the usage status (occupied / empty) of each seat based on the signals input from the seating sensor 34 and the seat belt sensor 35.

[0051] In addition, controller 1 may generate or update occupant information based on the detection of a human voice. The voice may be detected using an in-vehicle microphone, which may also be included in occupant sensor 3. Controller 1 may detect the opening and closing of doors from the output signal of the courtesy switch and acquire the possibility of people entering or exiting. Controller 1 may estimate the presence of a user as an occupant in the vehicle based on the power transmission module 2 receiving a signal transmitted from a pre-registered user device. The user device may be a smartphone or a wearable device, and may also be a power receiving device 9.

[0052] <Information presentation device> The information display device 4 is hardware used by the controller 1 to present information to the occupant. In this embodiment, the information display device 4 is used by the controller 1 to suggest changes in the position of the power receiving device 9, report the charging status, notify the occupant of their awareness status, and so on. The information display device 4 may be, for example, an instrument panel or a display installed on the ceiling. The display shows an image corresponding to the video signal input from the controller 1. The information display device 4 may also be a speaker.

[0053] The information display device 4 may also be a lighting device such as a spotlight. The spotlight, as the information display device 4, may operate under the control of the controller 1 to project light in a spotlight manner toward the recommended position. The recommended position refers to a location recommended for placing the charging device 9 inside the vehicle. The recommended position may be a location where wireless charging can be performed efficiently, or a location where the impact on the human body from charging radio waves can be minimized. The recommended position may be a location registered in advance, or it may be dynamically determined by the controller 1 considering the position of the occupants. The spotlight may be configured to change the direction of light projection using an actuator such as a motor. The controller 1 may be configured to suggest the recommended position using a projector instead of a spotlight. The equipment of the information display device 4 is an optional element, and the information display device 4 may be omitted in other embodiments.

[0054] <Controller> Controller 1 controls the operation of the power transmission module 2 and other in-vehicle devices. Controller 1 is configured as a computer. As shown in Figure 6, Controller 1 includes a processor 11, memory 12, and input / output circuit 13. The processor 11 is, for example, a CPU (Central Processing Unit). Controller 1 may have multiple processors 11. The memory 12 is a volatile storage medium such as RAM (Random Access Memory). The memory 12 may also include a non-volatile storage medium such as ROM (Read Only Memory) or flash memory. The memory 12 stores a power transmission control program, which is a program containing instructions for making a general-purpose computer function as Controller 1. The processor 11 executes the power transmission control program to provide the functions described below. Controller 1 corresponds to the control unit.

[0055] Furthermore, system configuration data is stored in memory 12. The system configuration data may be a dataset in which the installation locations of the power transmission modules 2 in the vehicle Hv are associated with module numbers. The installation locations of the power transmission modules 2 may be represented in a predetermined vehicle coordinate system. The vehicle coordinate system may be a two-dimensional coordinate system with the longitudinal direction of the vehicle Hv as the X-axis and the width direction as the Y-axis. The installation locations of the power transmission modules 2 included in the system configuration data may be used to calculate the device location.

[0056] The input / output circuit 13 is an interface for the processor 11 to communicate with other devices of the wireless power transmission system 100, such as the power transmission module 2. The input / output circuit 13 includes multiple input / output ports. The input / output circuit 13 may include a PHY chip that is compatible with the communication method with the other devices. The input / output circuit 13 is not limited to a wired communication interface and may include any wireless communication interface.

[0057] Controller 1 is connected to multiple power transmission modules 2, occupant sensors 3, and information display devices 4, and is configured to communicate with these devices using input / output circuits 13. Controller 1 is also connected directly or via an in-vehicle network to various on-board sensors (not shown). The in-vehicle network may be a local network established within the vehicle. Controller 1 acquires data from the on-board sensors indicating vehicle status, such as the vehicle's driving status (stopped / driving), door open / closed, and shift position.

[0058] Controller 1 operates one of the multiple power transmission modules 2 as a representative module. The representative module is a communication module for data communication with the power receiving device 9. Controller 1 uses the representative module to detect the power receiving device 9 located inside the vehicle. Controller 1 also uses the representative module to obtain device information of the power receiving device 9. The device information includes status information such as remaining power. Remaining power refers to the amount of power stored in the battery 92. Remaining power can also be expressed as remaining capacity, charge rate, remaining power, or SOC (State of Charge). The device information may also include information indicating the device type, such as whether it is a portable device or a fixed device. Furthermore, Controller 1 uses the representative module to exchange distance measurement settings with the power receiving device 9. Details of the distance measurement settings will be described separately.

[0059] Controller 1 obtains data indicating distance measurements from multiple power transmission modules 2 by having them perform distance measurement communication with the power receiving device 9. The distance measurement value is a parameter indicating the distance from the power transmission module 2 to the power receiving device 9. Once Controller 1 obtains distance measurement values ​​from each of the multiple power transmission modules 2, it estimates the device position coordinates using these multiple distance measurement values. The device position coordinates are the position coordinates of the power receiving device 9 in a 2D / 3D coordinate system based on a predetermined position of the vehicle Hv. The device position can be calculated using a method similar to three-point positioning or multi-point positioning used in positioning technology fields such as GPS (Global Positioning System). Multi-point positioning is a method in which the device position is determined by the intersection of multiple circles (spheres in the case of 3D) with the installation position of each power transmission module 2 as the center and the distance measurement value as the radius. Controller 1 may calculate the device position from a combination of the installation position of each power transmission module 2 and the distance measurement value.

[0060] Controller 1 controls the operation of the power transmission module 2 based on the estimated device location. For example, Controller 1 controls the directivity of the power transmission module 2 according to the device location. This aligns the power transmission direction, which is the direction in which the power transmission module 2 transmits charging radio waves, with the device location. Adjusting the directivity corresponds to adjusting the power transmission direction. Controller 1 also selects at least one power transmission module 2 (hereinafter also referred to as a drive module) to be used to charge the power receiving device 9, according to the device location. Details of the operation of Controller 1 related to charging control will be described separately.

[0061] <Distance communication> This section describes the distance measurement communication performed between the power transmission module 2 and the power receiving device 9. In this embodiment, the distance measurement communication between the power transmission module 2 and the power receiving device 9 is for CS (Channel Sounding) distance measurement. CS distance measurement is a method of measuring distance based on the difference in received phase for each channel, obtained by transmitting and receiving CW signals on multiple channels. CS distance measurement is sometimes called High Accuracy Distance Measurement (HADM), Phase-based Ranging (PBR), or Multi-channel Phase Difference Ranging. CS distance measurement communication includes performing bidirectional or unidirectional communication of CW signals on multiple channels.

[0062] The following describes the case where the transmission module 2 and the receiving device 9, as representative modules, perform CS distance measurement using a one-way method. The one-way method assumes that the initial phase of the CW signal for each frequency transmitted from the receiving device 9 is constant, and uses the received phase of the CW signal transmitted from the receiving device 9 directly as the basis for calculating the inter-frequency phase difference. The received phase (in other words, the propagation phase) used as the basis for calculating the inter-frequency phase difference can also be obtained by other methods such as the so-called passive two-way method and the active two-way method. The passive two-way method and the active two-way method will be described separately as supplementary information.

[0063] In this embodiment, the power receiving device 9 plays the role of transmitting a CW signal (a so-called reflector), and the power transmission module 2 plays the role of performing distance calculations based on the received CW signal (a so-called initiator). The roles of initiator and reflector in CS distance measurement may be swapped as appropriate. In a one-way system, the reflector may be replaced with a tag, transmitter, tone transmitter, etc. The initiator may be replaced with a measuring device, etc.

[0064] The series of processes for CS ranging (hereinafter referred to as CS ranging process) includes a preparation phase, a phase collection phase, and a calculation phase. The preparation phase is a phase in which the conditions for performing ranging are adjusted using data communication opportunities such as connection events. The phase collection phase is a phase in which received phase information from multiple channels is collected by actually transmitting and receiving CW signals from multiple channels. The received phases of multiple channels may be identified based on IQ data from multiple channels. The calculation phase is a phase in which the distance is calculated based on the collected received phases for each frequency.

[0065] Figure 7 shows the flow of distance measurement communication between the representative module and the power receiving device 9. Step S100 is the step in which the power transmission module 2, as the representative module, sends a distance measurement start request to the power receiving device 9. The distance measurement start request is an LE signal requesting the power receiving device 9 to start CS distance measurement. The distance measurement start request can be sent using a data channel after a communication connection with the power receiving device 9 has been established. In step S105, the power receiving device 9 sends back an affirmative response signal (so-called Ack) to the power transmission module 2 based on the receipt of the distance measurement start request.

[0066] In step S110, the power transmission module 2 sends a distance measurement setting message based on receiving an Ack from the power receiving device 9 for a distance measurement start request. The distance measurement setting message is a signal indicating the parameters for conducting communication for CS distance measurement. The parameters for conducting distance measurement communication may include the distance measurement start time, initial phase setting value, hopping interval, initial frequency, etc.

[0067] The distance measurement start time is a parameter that defines the timing at which the transmission and reception of CW signals (also called tone exchange) actually begin. The distance measurement start time may be a waiting time from the completion of the preparation phase until the transmission and reception of CW signals on the initial channel begins, for example, 400 milliseconds or 800 milliseconds. The initial phase setting defines the initial phase of the CW signal. The initial phase can basically be set to 0, but other values ​​may be specified. The hopping interval represents the time it takes to switch channels, in other words, the time it takes to maintain one channel. The initial frequency specifies the frequency of the CW signal to be transmitted first in a series of distance measurement communications. Channel (frequency) information may be expressed, for example, by a channel number.

[0068] In step S115, the power receiving device 9 sends an Ack to the power transmitting module 2 based on having received the distance measurement setting message. In step S120, the power transmitting module 2 transitions to a state where it can receive a signal of the initial frequency, i.e., a receive standby state, based on having received the Ack from the power receiving device 9. The transition to the receive standby state may occur at or a predetermined time before the distance measurement start time.

[0069] In step S125, the power receiving device 9 starts transmitting a CW signal at the initial frequency according to the distance measurement start time. The transmission of the CW signal may be stopped, for example, after a certain period of time has elapsed since the start. The CW transmission time (also called tone length), which is the duration for which the CW signal is transmitted, should be set to be shorter than the hopping interval. In other embodiments, the power receiving device 9 may start transmitting a CW signal after the distance measurement settings have been agreed upon and based on the receipt of a predetermined transmission request from the power transmission module 2.

[0070] When the transmission module 2 receives a CW signal from the power receiving device 9, in step S130 it detects the received phase and stores the value of the received phase along with frequency information (e.g., channel number) in memory 25. In step S140, the transmission module 2 and the power receiving device 9 automatically switch the channels being used at the hopping interval agreed upon in step S110. The channel numbers may transition one by one, or they may be changed according to the rules defined in the distance measurement settings.

[0071] When the receiving device 9 switches the channel in use, in step S145 it transmits a CW signal for the new channel. The transmitting module 2 also switches the channel in use and transitions to a state where it can receive signals for the new channel. Then, in step S150, the transmitting module 2 observes and acquires the received phase at the switched frequency.

[0072] The transmission module 2 and the receiving device 9 repeat the frequency switching and receiving phase acquisition process described above until they have collected the received phase at all frequencies for which the received phase should be acquired. For example, the above process may be performed for all channels (0-36Ch) that can be used for data communication (also called GATT communication). The transmission module 2 and the receiving device 9 may terminate the repeated process when they have collected the received phase at a predetermined number of frequencies. The number of exchanges, which is the number of channels for transmitting and receiving CW signals, may be the same as the number of data channels, or it may be smaller. The number of exchanges may be 5, 16, 32, etc.

[0073] In one embodiment, the power transmission module 2 transmits a distance measurement completion notification signal to the power receiving device 9 in step S160 when it has collected a specified number of received phases for a given number of channels. The distance measurement completion notification signal may be a data signal to notify that CW distance measurement communication has ended. Based on receiving the distance measurement completion notification signal, the power receiving device 9 may switch to normal data communication mode. The transmission and reception of the distance measurement completion notification signal are optional elements and may be omitted. Based on receiving the distance measurement completion notification signal, the power receiving device 9 may return an Ack to the power transmission module 2.

[0074] Once the transmission module 2 has finished collecting the received phase for each frequency, in step S170 it calculates the phase shift coefficient (α). The phase shift coefficient is a parameter that indicates the degree to which the received phase changes in response to changes in frequency. The phase shift coefficient can also be called the degree of phase change, phase shift amount, or phase-frequency correlation coefficient.

[0075] In a simplified method, the phase shift coefficient can be calculated based on the received phase observed at any two frequencies, namely the first and second frequencies. If we assume that Δf is the difference frequency between the first and second frequencies, Δφ is the inter-frequency phase difference (the difference between the received phases observed at the first and second frequencies), and α is the phase shift coefficient, then the relationship α = Δφ / Δf holds. The inter-frequency phase difference (Δφ) is the difference in received phases observed at two different frequencies. The inter-frequency phase difference (Δφ) can also be called the two-frequency phase difference. The inter-frequency phase difference (Δφ) corresponds to the displacement of the phase angle due to the change in the channel used.

[0076] In this embodiment, the power transmission module 2 calculates a regression line showing the relationship between frequency and reception phase based on the reception phase for each frequency, in order to measure distance with higher accuracy, and adopts the slope of the regression line as the phase change coefficient. This is because the slope of the regression line indicates the amount of change in reception phase with respect to the amount of frequency displacement. The regression line can be calculated using various methods, such as the least squares method. If the regression line is expressed as y = a·x + b, the coefficient a of x corresponds to the slope of the regression line. In the above formula, "x" is the variable corresponding to frequency, and "y" is the variable corresponding to reception phase. The regression line can also be called an approximation line.

[0077] The power transmission module 2 may provisionally calculate a first regression line based on all observed received phase data, and then recalculate a second regression line after excluding values ​​(so-called outliers) whose distance from the provisionally calculated first regression line is greater than or equal to a predetermined value. In this case, the power transmission module 2 may use the slope of the second regression line as the phase change coefficient. Thus, the phase change coefficient used for distance calculation may be determined based on a regression line whose population is data excluding outliers. This configuration can improve the accuracy of the inter-frequency phase difference and, consequently, the distance measurement accuracy.

[0078] In other embodiments, the power transmission module 2 may calculate the inter-frequency phase difference (Δφ), the difference frequency (Δf), and the phase change coefficient for each combination of frequencies for which the received phase can be observed. The power transmission module 2 may also use the average or median value of the phase change coefficient for each combination of frequencies as the phase change coefficient for distance calculation. Thus, the phase change coefficient (α) can be generated in various ways based on received phase information at multiple frequencies.

[0079] In step S180, the power transmission module 2 calculates the device distance (D) using the phase change coefficient (α). If the device distance is D, then the relationship between the difference frequency Δf and the inter-frequency phase difference (Δφ) is D∝C·Δφ / (2π·Δf)=C·α / 2π. In the above equation, the parameter "C" represents the propagation speed of radio waves (3×10^8 m / sec). The power transmission module 2 calculates the device distance based on this relationship. For example, the power transmission module 2 can calculate the device distance using equation 1: D=k·C·α / 2π. The parameter k in equation 1 is a design value and is set to 1.0 or 0.5. The value of k may be determined by whether the transmission / reception phase difference is calculated as a phase change coefficient for one way or as a phase change coefficient for both ways. The power transmission module 2 transmits data (also called distance data) showing the calculated distance measurement value to the controller 1.

[0080] In CS distance measurement using a one-way system, transmission modules 2 other than the representative module (hereinafter also referred to as listening modules) can calculate the distance measurement value by listening to the CW signal emitted by the power receiving device 9. Therefore, in one embodiment, after the representative module exchanges distance measurement settings with the power receiving device 9, the controller 1 also notifies the listening modules of the said distance measurement settings. Multiple listening modules, according to the notified distance measurement settings, enter a reception standby state, for example, from the distance measurement start time, and observe the CW signal emitted from the power receiving device 9. The listening modules also collect the received phase for each channel and calculate the phase change coefficient and, consequently, the distance measurement value. The listening modules also provide distance data indicating the distance measurement value to the controller 1. Thus, in this embodiment, by applying sniffing technology, multiple transmission modules 2 simultaneously (in parallel) receive the CW signal emitted from the power receiving device 9 and generate the distance measurement value.

[0081] In this embodiment, the power transmission module 2 is assumed to have a function for calculating the phase change coefficient and distance measurement value, but it is not limited to this. The controller 1 may have the function for calculating the phase change coefficient, etc. In this case, the power transmission module 2 only needs to collect the received phase for each frequency and transmit the collected data to the controller 1.

[0082] <Charge control> Here, the charging control process (also called the charging process) performed by the controller 1 in cooperation with the power transmission module 2, etc., will be explained using the flowchart in Figure 8. Figure 8 may represent, for example, the process for charging a power receiving device 9 brought into the vehicle by the user of a vehicle Hv. Of course, Figure 8 may also represent the process for charging a power receiving device 9 that is fixed inside the vehicle. The flow shown in Figure 8 may be started, for example, by an entry operation. The entry operation may be opening and closing a door and may be detected based on the output signal of a courtesy switch. The entry operation may also be unlocking. The entry operation may also be a user operation on the outer door handle, etc. In other embodiments, the controller 1 may attempt to execute the charging process at regular intervals.

[0083] The charging process starts from S200. Upon receiving confirmation that the start conditions, which are predetermined conditions for starting the charging process, are met, the controller 1 searches for the power receiving device 9 in S200. The search for the power receiving device 9 may be performed by searching for previously registered devices via LE communication. If a communication connection is established with a device already registered as the power receiving device 9, the controller 1 may determine that there is a device to be charged (S205 YES). Alternatively, if an LE communication connection is not established with a device registered as the power receiving device 9, the controller 1 may determine that no device to be charged was found (S205 NO).

[0084] Controller 1 may have registered target conditions, which are the conditions for setting a discovered power receiving device 9 as a charging target. If Controller 1 discovers multiple power receiving devices 9, it may select a charging target according to the target conditions. In addition to being pre-registered, the target conditions may also include conditions such as the remaining power being below a predetermined threshold or being a user-provided device. Controller 1 may detect a device that satisfies the predetermined target conditions as a charging target. Controller 1 may detect a device that is pre-registered and has a remaining power below a predetermined value as a charging target. Controller 1 may receive device information from the power receiving device 9, indicating the remaining power or device type, through LE communication with the power receiving device 9.

[0085] If no device meeting the target conditions is found (S205 NO), wireless charging is stopped at S250 and this flow is terminated. On the other hand, if a device meeting the target conditions (i.e., a device to be charged) is found, the device location is determined at S210 by having each power transmission module 2 perform distance measurement communication with the device to be charged. If the device location determined at S210 is inside the vehicle, processing from S220 onwards continues. On the other hand, if the determined device location is outside the vehicle, the charging process may be stopped at S250 and this flow may be terminated.

[0086] In S215, Controller 1 uses the occupant sensor 3 to determine whether or not there is an occupant. If an occupant is detected (S220 YES), Controller 1 also determines the occupant's position in S225. The occupant's position is the location where the occupant is located inside the vehicle. The occupant's position corresponds to the position of the human body. The occupant's position may also be determined based on data input from the occupant sensor 3. By integrating data from multiple occupant sensors 3, Controller 1 may determine the occupant's position with high accuracy.

[0087] If no occupants are detected (S220 NO), controller 1 starts normal power transmission in S235. Normal power transmission here may mean that the power transmission module 2, according to the device location, transmits charging radio waves at a predetermined normal power level. The normal power level may be rephrased as the first level or strong level, etc. Similarly, the normal power level may be rephrased as normal intensity, basic intensity, or first intensity, etc. The normal power level may be an intensity that could affect the human body. The intensity that could affect the human body may be set based on the specific absorption rate (SAR).

[0088] For convenience, in this disclosure, the upper limit of the power range that does not affect the human body is referred to as the allowable power. The allowable power may vary depending on the frequency band. For example, at 2.4 GHz, the allowable power may be assumed to be 10 mW / MHz. In that assumption, the normal power level may be set to 15 mW / MHz or 20 mW / MHz. The normal power level may be set to a value greater than the allowable power. In other embodiments, the normal power level may be within the power range that does not affect the human body. In other words, the normal power level may be less than or equal to the allowable power. For example, the normal power may be 9 mW / MHz. The transmitted power may be defined as the sum of energy. The allowable value may be defined in the dimensions of dBm or mW, for example, 20 dBm or 100 mW. The operation of the power transmission module 2, which transmits charging radio waves at the normal power level as normal power transmission, corresponds to the rapid charging mode.

[0089] S235 may include the controller 1 selecting one power transmission module 2 (i.e., a drive module) from among a plurality of power transmission modules 2 to be used for charging the powered device 9, depending on the device's position. The drive module may be a power transmission module 2 located in the position that can charge the device most efficiently. For example, the drive module may be a power transmission module 2 that is free from obstacles such as headrests or backrests between itself and the device. The drive module may also be a power transmission module 2 located closest to the device.

[0090] Furthermore, S235 may include the controller 1 adjusting the directivity of the drive module according to the device position. The controller 1 directs the directivity of the drive module towards the device position. This can increase power supply efficiency. Note that the main beam of the power transmission module 2 (corresponding to the power transmission direction) is sufficiently focused. For example, the power transmission module 2 may be configured such that the power density in directions more than 45 degrees away from the power transmission direction is sufficiently small so as not to affect the human body.

[0091] On the other hand, if an occupant is detected (S220 YES), S230 determines whether power can be transmitted while avoiding the occupant, based on the occupant's position identified in S225. S230 can be understood as a step to determine whether there is a power transmission module 2 capable of transmitting power while avoiding a human body. A power transmission module 2 capable of transmitting power while avoiding a human body is also referred to in this disclosure as an avoidable module or a usable module. An avoidable module may be a power transmission module 2 that does not have a human body between it and the object to be charged. An avoidable module may be a power transmission module 2 in which the angle between the direction of human body presence and the direction of the object is greater than or equal to a predetermined value (e.g., 45 degrees). A power transmission module 2 capable of forming a charging path at a position sufficiently far from a human body may be selected as an avoidable module. The direction of human body presence is the direction in which the occupant is located as seen from the power transmission module 2. The direction of the object is the direction in which the object to be charged is located as seen from the power transmission module 2.

[0092] For example, if there is an occupant in the left front seat and the device to be charged is in the right rear seat, the fifth module 2E or the third module 2C may be an avoidable module. If there is an occupant in the left front seat and the device to be charged is in the right front seat, the fifth module 2E may be an avoidable module. The avoidable module may be determined by taking into account the occupant, the device to be charged, and the installation location of the power transmission module 2. The memory 12 may have a dataset pre-registered that shows the avoidable modules according to the combination of occupant position and device position. The controller 1 may search for an avoidable module based on this dataset.

[0093] In S230, if an avoidable module is detected, the controller 1 may start normal power transmission in S235 using the avoidable module. Power transmission using an avoidable module, that is, control that transmits power using a path that avoids the human body, will also be referred to as avoidable charging control below. In other embodiments, the intensity of the charging radio waves transmitted in avoidable charging control may be at a level that does not affect the human body. Avoidable charging control may also include the controller 1 adjusting the directivity of the avoidable module as a drive module according to the device position.

[0094] On the other hand, if no avoidable module is found in S230, controller 1 determines in S240 whether low-power transmission is permitted. Low-power transmission here refers to control that transmits charging radio waves at a predetermined suppression power level that does not affect the human body. The suppression power level may be set below the permissible value, for example, 8mW / MHz. The suppression power level may be rephrased as second level or weak level, etc. Also, the suppression power level may be rephrased as suppression strength, degeneracy strength, or second strength, etc.

[0095] Whether or not low-power transmission is permitted may be pre-registered in the memory 12 of the controller 1. The memory 12 may store charging setting data that indicates settings related to charging control. The controller 1 may determine whether or not low-power transmission is permitted by referring to the charging setting data. In other embodiments, the controller 1 may use the information display device 4 to ask the occupant whether or not low-power transmission is permitted. The controller 1 may also determine whether or not low-power transmission is permitted based on the occupant's operation input.

[0096] If low-power transmission is permitted (S240 YES), controller 1 starts low-power transmission in S245. The transmission module 2 used for low-power transmission may be a transmission module 2 located in a position where charging radio waves do not reach the human body as much as possible. Low-power transmission may also be performed using the transmission module 2 closest to the device location from the viewpoint of power efficiency. Control of low-power transmission may also include controller 1 adjusting the directivity of the drive module according to the device location. Controller 1 may be configured to perform low-power transmission as an emergency measure only when the remaining power of the device to be charged is low. Low remaining power may be understood as the remaining power being less than a predetermined threshold (e.g., equivalent to 20%).

[0097] On the other hand, if low-power transmission is not permitted (S240 NO), controller 1 terminates wireless charging in S250 and ends this flow. Note that the determination in S240 is an optional element and may be omitted. Controller 1 may be configured to terminate the charging process in S250 if no suitable avoidable module is found in S230.

[0098] With the above configuration, the device location is determined with high precision by distance measurement communication. Therefore, a decrease in power supply efficiency due to misidentification of the device location can be avoided. In other words, the microwave charging efficiency can be increased. Furthermore, the controller 1 appropriately selects the power transmission module 2 according to the determined device location and adjusts the directivity of the power transmission module 2. This can further increase the charging efficiency. Changing the drive module according to the device location is also an example of changing the charging method.

[0099] Furthermore, controller 1 changes the charging method depending on the device's location and the presence or absence of occupants. If there are no occupants, it transmits a charging radio signal with a relatively strong power level. This can increase the charging speed. If there are occupants, it attempts to charge at a normal power level while avoiding the occupants. This allows the receiving device 9 to be charged relatively efficiently while ensuring the safety of the occupants, even when occupants are present. Also, if occupants are present and there are no avoidable modules, it performs slow wireless charging at a power level that does not affect the human body. This reduces the charging speed, but allows the receiving device 9 to be charged safely even in environments where occupants are present.

[0100] Furthermore, the controller 1 described above estimates the occupant's position using multiple sensors in a single phase. With this configuration, the occupant's position can be estimated with high accuracy. Therefore, the risk of irradiating the occupant with charging radio waves can be reduced. In addition, by estimating both the occupant's position and the device's position with high accuracy, the loss of charging opportunities can be reduced, making it possible to achieve both improved charging efficiency and improved occupant safety.

[0101] <Supplementary information on charging process> The charging process (also called charging control) described above may be performed each time the door is opened or closed. Once the drive module starts transmitting charging radio waves, it continues to transmit charging radio waves until a predetermined time has elapsed or a predetermined interruption event, such as the opening or closing of a door, is detected. Upon detecting an interruption event, the controller 1 sends a command to the drive module to stop power transmission. Interruption events may include opening doors or windows, or occupants leaving or moving. The controller 1 may also terminate charging of the charging target when the remaining power level of the charging target exceeds a predetermined value. The controller 1 and the charging target may periodically communicate data regarding the charging status.

[0102] The S215 check may be performed periodically even after power transmission has started. In particular, the S215 check may be performed periodically if the windows of the vehicle Hv are open. This will allow charging to be stopped if a person enters through the window. In conjunction with the periodic execution of S215, the occupant position check in S225 may also be performed periodically.

[0103] If the vehicle Hv is a passenger car and no movement of occupants is expected while the vehicle is in motion, periodic determination of occupant positions may be suspended while the vehicle Hv is moving. If the vehicle Hv is a bus or the like and occupant movement may occur while the vehicle is in motion, periodic determination of occupant positions may be performed even while the vehicle Hv is in motion.

[0104] <Charging control that takes movement into consideration> Controller 1 may prohibit charging processing depending on the movement status of the vehicle Hv, or it may be configured to perform charging processing in a manner that corresponds to the movement status of the vehicle Hv. The movement status of the vehicle Hv may be either stopped or in motion. Stopping may include the state in which the vehicle Hv is parked and locked.

[0105] For example, controller 1 may be configured to perform charging processing only when the vehicle is stopped, as shown in Figure 9. Specifically, controller 1 may perform processing from S200 onwards after detecting that the vehicle Hv has stopped. Controller 1 may also periodically perform processing from S200 onwards while the vehicle Hv is stopped. The movement status of the vehicle Hv may be determined by input signals from on-board sensors. S300 shown in Figure 9 is a step to determine whether the vehicle is stopped or not based on signals from on-board sensors, and S305 is a step to perform the charging processing shown in Figure 8.

[0106] Furthermore, the controller 1 may change the type of power receiving device 9 to be charged depending on the vehicle's movement status. For example, as shown in Figure 10, if the controller 1 determines in S400 that the vehicle is stopped, it may execute a charging process targeting a fixed device in S405. A charging process targeting a fixed device is a process for charging a power receiving device 9 installed inside the vehicle. This charging process for a fixed device may be implemented by including the condition that the device is a fixed device as a target condition. Whether a device is a fixed device or a device brought in by the user may be registered in the controller 1 in advance. The controller 1 may also be configured to store a power receiving device 9 as a fixed device when it determines that the vehicle Hv is parked and there are no occupants inside. The controller 1 may store device type information linked to a device ID.

[0107] On the other hand, if controller 1 determines in S400 that the vehicle is not stopped, it may perform a charging process for the user's personal device in S410. The charging process for the user's personal device is a process for charging the power receiving device 9 that has been temporarily brought into the vehicle by the user. The charging process for the personal device may be implemented by including the condition that the device is a personal device in the target conditions.

[0108] According to the above configuration, the fixed device is charged while the vehicle is stopped, including when parked, so it can be expected that the fixed device will already be fully charged when the occupants use the vehicle's hybrid system. Therefore, the frequency of wireless charging when occupants are present can be reduced. In addition, when occupants are present, the user's personal devices will be given priority for wireless charging, which can improve occupant convenience. In other embodiments, if it is determined that the vehicle is not stopped, the system may be configured to prioritize charging devices with low remaining power, regardless of device type.

[0109] <Supplementary information on normal power transmission> The control related to normal power transmission may include multiple steps, as shown in Figure 11. That is, in the initial step S500 of the normal power transmission control, the controller 1 attempts low-power transmission. Low-power transmission may involve transmitting charging radio waves at a power level that does not affect the human body (e.g., a suppression power level). The suppression power level corresponds to the trial intensity.

[0110] After continuing low-power transmission for a certain period of time, controller 1 acquires data indicating the amount of power received through data communication with the power receiving device 9 (S505). The amount of power received is the amount of power received by the power receiving device 9. If the amount of power received is less than a predetermined expected value (S510 YES), controller 1 either continues low-power transmission in S515 or attempts to perform avoidant charging control. This is because if the amount of power received is less than the expected value, there is a possibility that a human body is in the power transmission path. On the other hand, if the amount of power received is equal to or greater than the predetermined expected value (S510 NO), controller 1 increases the power of the charging radio waves to be transmitted to the normal power level and continues power transmission (S520).

[0111] Basically, controller 1 uses occupant sensors 3 to determine the presence or absence of occupants, but it is not always possible to detect occupants perfectly. There is a non-zero possibility of occupant detection being missed. As described above, safety can be further enhanced by increasing the power transmission strength only after confirming that no occupants are present on the transmission path based on the results of low-power transmission. In addition, if it is confirmed that there are no occupants, the amount of charge per unit time can be increased in order to increase the power transmission strength.

[0112] The control described above corresponds to a method for verifying the presence or absence of occupants based on the amount of power received for low-power transmission. As disclosed herein, the controller 1 may be configured to determine the presence or absence of occupants based on the amount of power received by the power receiving device 9 for low-power transmission. The determination in S215 may be achieved by steps S500 to S510. By using a method to detect occupants based on the trial results of low-power transmission, it becomes unnecessary to provide an additional occupant sensor 3, and the introduction cost of the wireless power transmission system 100 can be reduced. Furthermore, by using a configuration that generates occupant information by combining the trial results of low-power transmission and the detection results of the occupant sensor 3, it becomes possible to determine the presence or absence of occupants with greater accuracy.

[0113] Incidentally, if the received power is below a predetermined expected value, there is a non-zero possibility that the device position is being misidentified. If it is determined in S505 that the received power is below a predetermined expected value, the ranging communication may be re-executed to re-recognize the device position. Also, if it is determined in S505 that the received power is below a predetermined expected value, the beam of the drive module may be changed to a predetermined pattern. If it is determined that the received power is below a predetermined expected value in any beam setting, S520 may be executed in that beam setting.

[0114] <Proposed placement of power receiving devices> The above describes one embodiment in which low-power transmission is performed when avoidance charging control is not possible, but the system response when avoidance charging control is not possible is not limited to this. When avoidance charging control is not possible, the controller 1 may perform a position suggestion process, which is a process of presenting a recommended position for the power receiving device 9 using the information presentation device 4. The recommended position is a position in which the occupant does not directly receive charging radio waves. The recommended position may be determined according to the occupant's position.

[0115] The location suggestion process may include a display process that shows an image indicating the recommended location on a display. The location suggestion process may include an announcement process that outputs an audio message indicating the recommended location from a speaker. The location suggestion process may include a projection process that uses a spotlight or projector to brightly illuminate the recommended location. The location suggestion process may consist of a display process, an announcement process, a projection process, or a combination thereof.

[0116] Controller 1 may perform a suggestion process to prompt the device to change its position to the recommended position even if the remaining power of the power receiving device 9 is below a predetermined value and the device is located outside the predetermined recommended position. The recommended position may be a location where the centralized charging control described below is possible. That is, the recommended position may be a location where charging can be performed using two or three power transmission modules 2 in parallel while mitigating the impact on the human body.

[0117] <Centralized charging control using multiple power transmission modules> The above describes an embodiment in which a power receiving device 9 is wirelessly charged using one of several power transmission modules 2, but the method of wirelessly charging the power receiving device 9 is not limited to this. The controller 1 may be configured to charge one power receiving device 9 using multiple power transmission modules 2 in parallel (in other words, simultaneously). For convenience, control that simultaneously drives multiple power transmission modules 2 to charge the same device is referred to as centralized charging control.

[0118] However, when multiple power transmission modules 2 transmit charging radio waves simultaneously, the charging radio waves transmitted from each power transmission module 2 may interfere with each other. For example, when the first module 2A and the second module 2B are driven simultaneously, the following may occur: If the charging radio wave transmitted by the first module 2A and the charging radio wave transmitted by the second module 2B are received by the power receiving device 9 in the same phase, they will reinforce each other. Specifically, as shown on the right side of Figure 12, the power receiving device 9 may receive a charging radio wave with twice the amplitude. Since amplitude corresponds to power, the received power will be greater than when charging using one power transmission module 2, and the charging speed may increase.

[0119] On the other hand, if the charging radio waves transmitted by the first module 2A and the charging radio waves transmitted by the second module 2B are received by the receiving device 9 in opposite phases, they will cancel each other out. Specifically, as shown on the right side of Figure 13, the combined wave received by the receiving device 9 may have an amplitude of approximately 0. Thus, depending on the phase angle of the second charging radio wave relative to the first charging radio wave, the charging efficiency may decrease. The first charging radio wave is the charging radio wave transmitted by the first module 2A. The second charging radio wave is the charging radio wave transmitted by the second module 2B. The reception phase of the charging radio waves at the receiving device 9 is affected by the distance from the receiving device 9 to the transmitting module 2. Therefore, even if the timing of when multiple transmitting modules 2 start transmitting charging radio waves is perfectly synchronized, efficiency degradation due to differences in reception phases may still occur.

[0120] Note that Figure 12 shows a composite wave with an amplitude twice that of the received wave from the first module 2A. However, in reality, the distance to the receiving device 9 may differ for each transmission module 2. Therefore, the amplitude of the received wave may differ for each transmission module 2. Thus, please note that the actual amplitude of the composite wave may differ from twice the individual strength. Similarly, please note that the amplitude of the composite wave in Figure 13 may not be exactly zero. The individual strength is the received strength of the charging radio waves transmitted from one transmission module 2, and corresponds to the amplitude of the waveform shown on the left side of Figure 12.

[0121] Based on such technical circumstances, in one embodiment, the controller 1 may be configured to adjust the transmission settings of the second module 2B based on the received signal strength observed by the power receiving device 9 when the first module 2A and the second module 2B are actually driven simultaneously. The controller 1 obtains the received signal strength observed by the power receiving device 9 through LE communication with the power receiving device 9. The received signal strength corresponds to the received power. In the following description, the term "received signal strength" may be replaced with "received power."

[0122] For example, controller 1 controls the first module 2A and the second module 2B in the procedure shown in Figure 14. That is, controller 1 starts the first module 2A to transmit a charging radio wave of the fundamental frequency at S600. Next, while the first module 2A is transmitting a charging radio wave of the fundamental frequency, controller 1 also causes the second module 2B to transmit a charging radio wave of the fundamental frequency (S605). After that, controller 1 changes the transmission setting of the charging radio wave in the second module 2B at predetermined time intervals until the received strength (in other words, received power) at the power receiving device 9 reaches a sufficient level. For example, controller 1 changes the phase of the charging radio wave by a predetermined amount at predetermined intervals.

[0123] Figure 15 shows the interaction between the first module 2A, the second module 2B, the power receiving device 9, and the controller 1 corresponding to this flow. The time T1 shown in Figure 15 represents the time when the second module 2B begins to transmit charging radio waves. In Figure 15, the power transmission start timing of the first module 2A and the power transmission start timing of the second module 2B coincide, but this is not limited to this. The power transmission start of the first module 2A may precede the power transmission start of the second module 2B.

[0124] Figure 15 shows an example of control in which the phase of the charging radio waves transmitted by the second module 2B is changed by 30° increments. However, the amount of phase shift in one shift change may be 10°, 20°, or 45°, etc. The setting change interval TL, which corresponds to the period for which one phase setting is maintained, may be designed as appropriate. The setting change interval TL may be set to a value longer than the measurement time described later. The setting change interval TL may be set to an integer multiple of the period of the fundamental frequency. In the figure, f0 represents the fundamental frequency. θ0 represents the initial phase of the charging radio waves in the first module 2A and may be any value. f0 and θ0 may constitute the basic setting.

[0125] Prior to driving the second module 2B, the controller 1 may send a measurement request message via LE communication to the power receiving device 9, which is a message requesting measurement of the received signal strength. The measurement request may include data indicating a schedule for changing the transmission settings of the charging radio waves. The data indicating a schedule for changing the transmission settings of the charging radio waves may also include data indicating the setting change interval, etc. The power receiving device 9 measures the received signal strength at the timing specified in the request from the controller 1.

[0126] The power receiving device 9 measures the received signal strength for a predetermined measurement time starting from the timing when the phase setting switches, and transmits feedback data indicating its magnitude to the controller 1. The received signal strength included in the feedback data may be a parameter corresponding to amplitude. The received signal strength reported by the power receiving device 9 to the controller 1 may be the maximum value of the received signal strength observed during the measurement period, or the average of the absolute values. The feedback data may also be data indicating the total value of the received power during the measurement period instead of the received signal strength. The measurement period refers to the period from the timing of the phase change until the measurement time has elapsed. The measurement time may be designed as appropriate and may be set to a length suitable for measuring the received signal strength / received power in the power receiving device 9.

[0127] The power receiving device 9 may measure the received signal strength and transmit feedback data whenever the phase setting changes, for example. The feedback data may be a dataset indicating whether the amount of power received is sufficient for the required power, instead of the observed received signal strength value. In one phase, the feedback data can function as a message requesting the controller 1 to change the transmission setting (in this case, the phase setting) of the second module 2B. The communication between the power receiving device 9 and the controller 1 at times T21, T22, T23, and T24 in Figure 15 represents the transmission and reception of feedback data. While the first module 2A is transmitting charging radio waves, data communication between the controller 1 and the power receiving device 9 may be performed using a frequency other than the fundamental frequency to avoid interference.

[0128] Controller 1 receives feedback data in S610. Then, in S615, it determines whether the amount of power received in the second module 2B is sufficiently large based on the received feedback data. For example, it determines whether the received strength fed back from the power receiving device 9 is above a predetermined threshold. The adopted threshold may be a fixed value, or it may be, for example, 1.4 times the received strength observed when the first module 2A is transmitting power alone.

[0129] If controller 1 determines in S615 that the received signal strength in the second module 2B is not sufficiently high (S615 NO), controller 1 instructs the second module 2B to change its transmission settings according to a predetermined rule in S620. Specifically, controller 1 instructs the second module 2B to shift the phase from the current setting by a predetermined amount (30° in this case).

[0130] Controller 1 searches for a transmission setting that allows for charging with sufficient strength by repeating steps S610, S615, and S620. If Controller 1 determines in S615 that the received signal strength in the second module 2B is sufficient (S615 YES), it transmits a message to the second module 2B to maintain that setting and terminates the flow. Figure 15 shows the case where sufficient received signal strength is achieved when the phase angle is shifted by 120° from the initial phase. Centralized charging control may continue from S625 onward until an interruption event is detected. Centralized charging control here may be performed as the normal power transmission control described above in S235, etc.

[0131] The above describes a method to mitigate / eliminate the cancellation of charging radio waves that may occur when multiple power transmission modules 2 are driven simultaneously by shifting the phase angle. However, this is not the only way to mitigate the reduction in charging speed due to cancellation. The reduction in charging capacity due to interference can also be mitigated by changing the frequency of the charging radio waves transmitted by the second module 2B (i.e., the charging frequency) to a frequency different from the fundamental frequency.

[0132] For example, controller 1 may perform centralized charging control using the procedure shown in Figure 16. The series of processes shown in Figure 16 may normally be performed as power transmission control in S235 or similar. As the initial step S700 of centralized charging control, controller 1 starts transmitting charging radio waves to the first module 2A and the second module 2B with common transmission settings. The common transmission settings may be basic settings. After a predetermined time has elapsed, controller 1 communicates data with the power receiving device 9 in S705 and obtains the amount of power received by the power receiving device 9. Then, in S710, controller 1 determines whether the amount of power received is above a predetermined threshold.

[0133] If the received power is above the adopted threshold (S710 YES), controller 1 continues to supply power to the first module 2A and the second module 2B with the current settings (S715). On the other hand, if the received power is below the adopted threshold (S710 NO), controller 1 switches the charging frequency of the second module 2B to a bypass frequency different from the fundamental frequency in S720. The bypass frequency may be any frequency belonging to the 2.4GHz band.

[0134] With the above configuration, if sufficient received power can be achieved by simultaneously driving the two power transmission modules 2 with common basic settings, the operation will continue. On the other hand, if the received power is insufficient, the frequency of one of the power transmission modules 2 will be changed. Because the frequencies of the two charging radio waves are different, the composite wave may become a waveform whose amplitude increases and decreases periodically, as shown on the right of Figure 17. When the frequencies of the two radio waves are different, the state in which the two charging radio waves cancel each other out will not continue. Intervals in which the signal strength exceeds the individual strength may occur periodically. Therefore, it is possible to avoid a situation in which the power receiving device 9 cannot be charged due to interference.

[0135] Furthermore, if the power receiving device 9 has multiple antennas, the receiving frequency for each antenna may be switched. If the power receiving device 9 has a 2.4GHz first antenna and a second antenna, the first antenna may be configured to receive the fundamental frequency and the second antenna to receive the avoidance frequency. In addition, the charging frequencies of the first module 2A and the second module 2B may be different from each other, and the charging frequency of the first module 2A may also be changed to a frequency different from the fundamental frequency.

[0136] Furthermore, the parameters constituting the transmission settings are not limited to frequency and phase. The transmission settings may also include polarization. If the power transmission module 2 is equipped with multiple antennas 21 with different polarizations, S620 or S720 may be a process for switching polarizations. If the power transmission module 2 is configured to be able to switch polarizations, the power receiving device 9 may also be configured to be able to switch polarizations. The power receiving device 9 may also be configured to be able to receive circularly polarized signals.

[0137] The above describes a pattern in which the first module 2A and the second module 2B are driven in parallel to explain the flow of centralized charging control, but the combination of the two power transmission modules 2 used for centralized charging control is not limited to this. The controller 1 may select the power transmission modules 2 used for centralized charging control according to the device location. One of the two power transmission modules 2 used for centralized charging control is also called the first drive module, and the other is also called the second drive module. The first drive module is not limited to the first module 2A, but may be any other power transmission module 2. Similarly, the second drive module is not limited to the second module 2B, but may be any other power transmission module 2. The first drive module selected based on the device location, etc. corresponds to the first power transmission module. The second drive module selected based on the device location, etc. corresponds to the second power transmission module.

[0138] The selection rules for the power transmission module 2 used for centralized charging control may be the same as the selection rules for the drive module. The controller 1 may preferentially select a power transmission module 2 located close to the device location as the drive module for centralized charging. Furthermore, the controller 1 may be configured not to select a power transmission module 2 in which a human body may be present in the power transmission path connecting the power transmission module 2 and the device to be charged as the drive module for centralized charging. The controller 1 may be configured to perform centralized charging control if it has detected an occupant and there are two or more avoidable modules.

[0139] In addition, the number of power transmission modules 2 used for centralized charging control is not limited to two. Controller 1 may perform centralized charging control using three or more power transmission modules 2. In that case, the transmission settings of the second power transmission module may be determined in accordance with the procedure described above to match the charging radio waves transmitted by the first power transmission module, and then the transmission settings of the third power transmission module may be determined. The operating settings of multiple power transmission modules 2 may be determined one by one in a stepwise manner.

[0140] For example, controller 1 selects the first, second, and third drive modules according to the device location. If there are occupants, the controller may also consider the occupant locations in addition to the device locations when selecting the three drive modules. The third drive module selected based on the device location corresponds to the third power transmission module. Controller 1 drives the first drive module with predetermined basic settings. Then, with the first drive module running and the third drive module stopped, controller 1 causes the second drive module to transmit charging radio waves while switching the transmission settings at predetermined intervals. That is, the second drive module applies multiple transmission settings in sequence under the direction of controller 1. The process flow for determining the transmission settings of the second drive module may be as explained using Figures 14 and 15. Each time the transmission setting is changed, controller 1 receives feedback data indicating the received power from the power receiving device 9, and determines the second transmission setting based on the received feedback data. The second transmission setting is the transmission setting for charging radio waves in the second drive module.

[0141] Subsequently, when the first drive module is transmitting charging radio waves with its basic settings and the second drive module is transmitting charging radio waves with its second transmission settings, the controller 1 instructs the third drive module to transmit charging radio waves while switching its transmission settings at predetermined intervals. The controller 1 then receives feedback data indicating the received power from the power receiving device 9 each time the transmission settings are switched (in other words, periodically) and determines the third transmission setting. The third transmission setting is the transmission setting for the charging radio waves in the third drive module. After that, the power receiving device 9 is charged by the three drive modules transmitting charging radio waves with the settings determined by the above process. The more power transmission modules 2 are driven in parallel, the higher the amount of power received and the higher the amount of charge per unit time (i.e., the charging speed).

[0142] Furthermore, while the above describes an embodiment in which the controller 1 takes the lead in adjusting the transmission settings in the second module 2B, the receiving device 9 may also be the primary adjuster. In other embodiments, the receiving device 9 may analyze the received waveform and instruct each power transmission module 2 on the transmission settings. The receiving device 9 may also instruct multiple drive modules on the start timing of power transmission. The receiving device 9 may also synchronize the power transmission timing of multiple drive modules.

[0143] Incidentally, the phase of a charging radio wave completes one cycle for every wavelength. For example, the phase of a 2.4 GHz radio wave completes one cycle approximately every 125 mm. If we assume that the wavelength of the charging radio wave is λ and the remainder when the distance between devices is divided by the wavelength is γ, then the phase difference between the transmitted and received radio waves can be roughly estimated as 2π × (γ / λ). Considering these technical circumstances, the received phase of the charging radio wave transmitted from the power transmission module 2, as observed by the power receiving device 9, can be estimated from the distance measurement value indicating the distance between the devices. If the power transmission timing is synchronized, each drive module may be configured to estimate the received phase at the power receiving device 9 from the distance measurement value and adjust the initial phase of the transmitted charging radio wave so that the received phase is a common value. With such a configuration, it may be possible to transmit power without interference cancellation from immediately after the start of power transmission.

[0144] Controller 1 may change the number of power transmission modules used for charging depending on the device location. Controller 1 may perform centralized charging control in S235 if the power receiving device 9 is located in a location suitable for centralized charging, and otherwise perform individual charging control. Individual charging control is a control that transmits power using one power transmission module 2, and can be understood as the normal power transmission control described above. A location suitable for centralized charging is a place where multiple power transmission modules 2 can see in common. Data for centralized charging-compatible spots, which are locations suitable for centralized charging, may be registered in memory 12. Changing the number of power transmission modules 2 used for charging depending on the device location is also an example of changing the charging method depending on the device location.

[0145] <Parallel charging of multiple devices> Controller 1 uses a representative module to detect the number of internal devices, which is the number of power receiving devices 9 present inside the vehicle. For example, Controller 1 may consider the number of connected devices, which is the number of power receiving devices 9 that are communicating with the representative module, as the number of internal devices. Controller 1 may also use multiple power transmission modules 2 to determine the location of each detected power receiving device 9 through distance measurement communication. The multiple power transmission modules 2 may sequentially perform distance measurement communication with the multiple power receiving devices 9 based on instructions from Controller 1. The number of in-vehicle devices may be determined by excluding power receiving devices 9 that are determined to be outside the vehicle from among the communicating power receiving devices 9.

[0146] If the controller 1 detects multiple power receiving devices 9 in the vehicle, it may acquire status information including the remaining power of the power receiving devices and select a first and second charging target based on the status information. The second charging target may be a fixed device, but it is preferable that it be a device brought in by the user. The first and second charging targets may be selected based on the remaining power. In one situation, the controller 1 may prioritize setting the device with the lowest remaining power as the first charging target. If the controller 1 can acquire characteristic data such as the power consumption and power receiving efficiency of the power receiving devices 9 through communication, it may select the charging target considering the characteristic data. If the controller 1 determines, considering the remaining power, that there are no power receiving devices 9 that require emergency charging, it may set a power receiving device with high power receiving efficiency as the first or second charging target. For convenience, the location of the first charging target will be referred to as the first device location, and the location of the second charging target will be referred to as the second device location.

[0147] Controller 1 selects at least one drive module for the first charging target based on the first device position and performs wireless charging. This wireless charging may be centralized charging control or normal power transmission control. If the second device position and the first device position are far apart, Controller 1 may perform a parallel charging suggestion using the information display device 4. A parallel charging suggestion is a process that suggests to the occupants that the second charging target be placed near the first charging target.

[0148] Energy transmitted by the drive module to the first charging target that is not received by the first charging target can be wasted. To address this issue, if a second charging target is placed near the first charging target, the second charging target will also be charged by leaked radio waves. In other words, the first and second charging targets are charged in parallel. This reduces energy loss.

[0149] <Radar operation of the power transmission module> In addition to the LE communication function and the ranging communication function, the power transmission module 2 may be configured to operate as a radar. That is, it may be configured to transmit a CW signal as a probing wave and analyze the received results of the reflected wave and the transmitted wave to detect the position, movement, etc. of an object in the transmission direction. For example, the power transmission module 2 may be configured to operate as a radar using the FMCW (Frequency Modulated Continuous Wave) method or the FCM (Fast-Chirp Modulation) method. The power transmission module 2 performs transmission and reception of a probing wave based on an instruction from the controller 1 and outputs human body position data, which is data indicating the position where a person exists in the space. Thus, the power transmission module 2 may have a radar mode as an operation mode. The power transmission module 2 in the radar mode may be used instead of the UWB radar 31.

[0150] The controller 1 may obtain the presence or absence of an occupant and the occupant position by driving the power transmission module 2 as a radar. That is, the power transmission module 2 may also serve as an occupant sensor 3 (also referred to as a function). According to the configuration of detecting an occupant using the power transmission module 2, there is no need to provide an occupant sensor 3 separately from the power transmission module 2, and the introduction cost of the wireless power transmission system 100 can be reduced. The power transmission module 2 having a radar mode may also correspond to a sensor associated with the space.

[0151] <Supplementary Explanation of CS Ranging> The power transmission module 2 may obtain the propagation phase for each frequency by the active two-way method or the passive two-way method, and calculate the phase change coefficient and the ranging value using them. Here, the outlines of the active two-way method and the passive two-way method will be described.

[0152] The active two-way system is a method in which an initiator and a reflector transmit and receive CW signals to each other, each detecting the phase difference between the transmitted signal and the received signal, and using these two phase differences to determine the propagation phase. The active two-way system includes the steps of the initiator and reflector transmitting and receiving CW signals to each other, and the step of the reflector transmitting the observed received phase (θr) to the initiator.

[0153] If the phase observation error of the initiator is δi, the phase observation error of the reflector is δr, and the propagation phase that should be observed according to the one-way distance between the initiator and the reflector is φ, then the relationships θr = φ + δi - δr and θi = φ - δi + δr exist. Based on these relationships, the average of θi and θr is the propagation phase (φ) after the respective phase observation error components of the initiator and reflector have been canceled out. This propagation phase may be used as the receiving phase in a one-way system.

[0154] Thus, the active two-way system corresponds to a method that calculates the propagation phase as the average of the received phase at the initiator and the received phase at the reflector. Here, since the phase difference due to propagation in one direction is assumed, the propagation phase is the average of θi and θr. In another embodiment, when the phase difference due to propagation in both directions is assumed as the propagation phase, the propagation phase can be obtained as the sum of θi and θr. The controller 1 or the transmission module can calculate the distance measurement value based on the propagation phase for each frequency.

[0155] The passive two-way system is also a system in which the initiator and reflector transmit and receive CW signals to and from each other. The difference from the active two-way system is that the reflector reflects the received phase of the CW signal transmitted from the initiator into the phase observation error of the CW signal it transmits. For example, if the received phase at the reflector is θr, it transmits a CW signal expressed as z(t)=A·exp{-i(ωt+θr+2πn)}, where A represents the amplitude, ω is the angular frequency corresponding to the target frequency (f), and the relationship ω=2πf exists. n is a natural number and corresponds to the interval from when the reflector receives the CW signal until it transmits the CW signal.

[0156] According to this method, the received phase observed by the initiator does not include the reflector's phase observation error component. The received phase observed by the initiator is the same value as when a CW signal is received that has been reflected back by a reflector such as a wall. As a result, the initiator can calculate the propagation phase without obtaining the received phase from the reflector. The passive two-way method has the advantage of not requiring the reflector to transmit a received phase message compared to the active two-way method. As described above, propagation phase and, consequently, inter-frequency phase difference can be implemented using various methods. When employing the active / passive two-way method, multiple transmission modules 2 may individually perform distance measurement communication with the receiving device 9.

[0157] <Supplementary information on power transmission modules> The communication method between the power transmission module 2 and the power receiving device 9 is not limited to LE communication, but may also be UWB communication. The LE module 93 of the power receiving device 9 may be replaced with a module for UWB-IR. The antenna 21, power transmission circuit 22, and wireless control unit 24 of the power transmission module 2 may also be replaced with configurations compatible with UWB-IR. In other words, the power transmission module 2 and the power receiving device 9 may be configured to transmit and receive UWB pulses used in UWB communication.

[0158] In UWB communication, multiple channels can be used, as defined in IEEE 802.15.4z. For example, the power transmission module 2 and the power receiving device 9 may be configured to enable UWB communication using a fifth channel, including the 5.8 GHz band.

[0159] When the communication method between the power transmission module 2 and the power receiving device 9 is UWB-IR, the distance measurement method may be UWB distance measurement using UWB pulses. UWB distance measurement is a process that generates a distance measurement value based on the propagation time (in other words, flight time) of the UWB signal from the power transmission module 2 to the power receiving device 9. UWB distance measurement communication includes the steps of an initiator transmitting a pole signal and a responder transmitting a response signal upon receiving the pole signal. The pole signal is a UWB signal in a predetermined pattern that requests the responder to send a response. The response signal is a UWB signal as a response signal, and may be rephrased as an answer signal. Distance measurement communication may include the step of the initiator transmitting a final signal upon receiving the response signal.

[0160] If the power transmission module 2 supports UWB-IR communication, it may be configured to operate as a UWB radar. The controller 1 may generate crew information based on the results of operating the power transmission module 2 as a UWB radar.

[0161] Furthermore, the communication method between the power transmission module 2 and the power receiving device 9 is not limited to LE communication or UWB communication; it may also be Wi-Fi (compatible with W56), etc. The communication method between the power transmission module 2 and the power receiving device 9 may use a 920MHz band, 2.4GHz band, or 5.6(5.7)GHz band.

[0162] <Indication of charging status> When the controller 1 is performing or has performed charging radio waves (i.e., wireless charging), it may display information related to the system operation on the display, which serves as the information display device 4. The information related to the system operation may include at least one item such as (1) the recognized location of the power receiving device 9 to be charged, (2) the power transmission module 2 to be driven, (3) the transmission direction of the charging radio waves, (4) the transmitted power, (5) information about the device to be charged, and (6) the recognized location of the occupant.

[0163] <Supplementary information on system configuration> The representative power transmission module 2 may be built into the controller 1. Alternatively, the controller 1 may be built into one of the multiple power transmission modules 2 (for example, the representative module). The controller 1 and one power transmission module 2 may be integrated into a single unit.

[0164] Furthermore, the wireless power transmission system 100 may also include a communication module for data communication with the power receiving device 9, separate from the power transmission module 2. The power transmission module 2 does not necessarily have to be configured to communicate with the power receiving device 9. This communication module corresponds to the other communication module. The other communication module may be built into the controller 1 or placed at any location inside the vehicle.

[0165] The power receiving device 9 does not necessarily have to be a device powered by a battery 92. The power receiving device 9 may be powered by a primary battery. Alternatively, it may be a device that does not have a primary or secondary battery and is powered only by the power received by the power receiving circuit 931. The LE module 93 of a power receiving device 9 that does not have a battery may be configured to be powered by the power received wirelessly and then to perform distance measurement communication.

[0166] <Application> The wireless power transmission system 100 may be applied not only to vehicles but also to other types of mobile objects such as ships. Furthermore, the wireless power transmission system 100 may be applied to offices, residences, warehouses, and factories. Multiple power transmission modules 2 may be distributed among rooms in the building to which the system is applied. The target space is preferably a sealed space with restricted entrances and exits, such as a room or vehicle, but it may also be a designated outdoor space. When the wireless power transmission system 100 is applied to objects other than mobile objects, the term "occupants" above may be replaced with appropriate expressions such as "users," "residents," "visitors," "workers," or "employees," depending on the situation.

[0167] Furthermore, the entities that should be considered when performing wireless charging are not limited to humans; animals such as dogs and cats may also be included. Controller 1 may be configured to perform avoidance charging control and low-power transmission control when animals such as dogs are present in the target space, just as it would when humans are present. The presence or absence of animals such as dogs may also be determined based on the output of sensors associated with the target space, such as cameras or radar. [Explanation of Symbols]

[0168] 1 Controller (control unit), 2 Power transmission module, 3 Crew sensor, 4 Information display device, 9 Power receiving device, 21 Antenna, 22 Power transmission circuit, 23 Communication circuit, 24 Wireless control unit

Claims

1. A wireless power transmission system for wirelessly charging a power receiving device located within a target space, Multiple power transmission modules (2) are configured to transmit charging radio waves, which are radio waves used for charging, The system comprises a control unit (1) that controls the plurality of power transmission modules, The aforementioned plurality of power transmission modules include a first power transmission module and a second power transmission module, The control unit is configured to communicate wirelessly with the power receiving device using one of the multiple power transmission modules or another communication module. The control unit, The first power transmission module and the second power transmission module are driven in parallel, A wireless power transmission system configured to perform the following actions: adjust the transmission settings of the charging radio waves in the second power transmission module by communicating data with the power receiving device.

2. The control unit, The first power transmission module and the second power transmission module are driven in parallel. Feedback data indicating the received power at the power receiving device when the first power transmission module and the second power transmission module are driven in parallel is received from the power receiving device. The wireless power transmission system according to claim 1, configured to determine whether to maintain or change the transmission settings for the charging radio waves in the second power transmission module based on the received feedback data.

3. The control unit, While the first power transmission module is transmitting the charging radio waves, the transmission setting of the second power transmission module is changed at predetermined time intervals. Each time the transmission setting is switched, feedback data indicating the received power for that transmission setting is received from the power receiving device. The wireless power transmission system according to claim 1, configured to determine the transmission settings for the charging radio waves in the second power transmission module based on the received feedback data.

4. The control unit, While the first power transmission module is transmitting the charging radio waves, the phase of the charging radio waves transmitted by the second power transmission module is changed at predetermined intervals. Feedback data indicating the received power at the power receiving device in the phase after the phase change is received from the power receiving device. The wireless power transmission system according to claim 1, further configured to adjust the phase of the charging radio waves in the second power transmission module based on the received feedback data.

5. The control unit, The first power transmission module and the second power transmission module are both made to transmit the charging radio waves with predetermined basic settings. The power receiving device receives feedback data indicating the received power over a certain period of time. The wireless power transmission system according to claim 1, wherein if the received power indicated in the received feedback data is less than a predetermined value, the frequency of the charging radio waves in the second power transmission module is configured to be changed to a frequency different from the frequency of the basic setting.

6. The aforementioned multiple power transmission modules consist of three or more power transmission modules. Each of the aforementioned multiple power transmission modules is configured to communicate with the power receiving device for distance measurement, The control unit By having the multiple power transmission modules perform distance measurement communication with the power receiving device, distance data, which is data indicating the distance from each of the multiple power transmission modules to the power receiving device, is obtained. Based on the distance data, the device position, which is the location of the power receiving device within the target space, is identified. The wireless power transmission system according to claim 1, configured to select a power transmission module to operate as the first power transmission module and a power transmission module to operate as the second power transmission module from among the three or more power transmission modules according to the location of the device.

7. The aforementioned multiple power transmission modules consist of three or more power transmission modules. The plurality of power transmission modules include the first power transmission module, the second power transmission module, and the third power transmission module. In a situation where the first power transmission module transmits the charging radio waves with predetermined basic settings and the third power transmission module is stopped, the second power transmission module is instructed to sequentially transmit the charging radio waves with multiple transmission settings. The power receiving device receives feedback data indicating the received power for each transmission setting. Based on the received feedback data, the second transmission setting, which is the transmission setting for the charging radio waves in the second power transmission module, is determined. In a situation where the first power transmission module transmits the charging radio waves with the basic settings and the second power transmission module transmits the charging radio waves with the second transmission settings, the third power transmission module is instructed to sequentially transmit the charging radio waves with multiple transmission settings. The power receiving device receives feedback data indicating the received power for each transmission setting. The wireless power transmission system according to claim 1, configured to determine a third transmission setting, which is the transmission setting for the charging radio waves in the third power transmission module, based on the received feedback data.

8. The aforementioned multiple power transmission modules consist of four or more power transmission modules. Each of the aforementioned multiple power transmission modules is configured to communicate with the power receiving device for distance measurement, The control unit By having the multiple power transmission modules perform distance measurement communication with the power receiving device, distance data, which is data indicating the distance from the multiple power transmission modules to the power receiving device, is obtained. Based on the distance data, the device position, which is the location of the power receiving device within the target space, is identified. The wireless power transmission system according to claim 7, configured to select from among the four or more power transmission modules to operate as the first power transmission module, the second power transmission module, and the third power transmission module, depending on the location of the device.

9. The control unit, By communicating with the aforementioned power receiving device, the number of power receiving devices in the target space is detected. If multiple power receiving devices are detected, status information for each power receiving device is obtained through communication with each power receiving device. The wireless power transmission system according to claim 1, configured to select a charging target based on the status information for each of the power receiving devices.

10. Each of the aforementioned multiple power transmission modules is configured to communicate with the power receiving device for distance measurement, The device further comprises an information presentation device (4) for presenting information to a person present in the aforementioned target space, The control unit, By communicating with the aforementioned power receiving device, the number of power receiving devices in the target space is detected. If multiple power receiving devices are detected, status information for each power receiving device is obtained through communication with each power receiving device. Based on the status information for each of the power receiving devices, a first charging target and a second charging target are selected from among the plurality of power receiving devices. By having the multiple power transmission modules perform distance measurement communication with the first charging target, distance data, which is data indicating the distance from the multiple power transmission modules to the first charging target, is obtained. Based on the distance data, the first device position, which is the position of the first charging target within the target space, is obtained. By having the multiple power transmission modules perform distance measurement communication with the second target to be charged, distance data, which is data indicating the distance from the multiple power transmission modules to the second target to be charged, is obtained. Based on the distance data, the second device position, which is the position of the second charging target within the target space, is obtained. The wireless power transmission system according to claim 1, wherein, if the location of the first device and the location of the second device are far apart, the system is configured to perform a suggestion process using the information presentation device to suggest placing the second charging target near the first charging target.

11. Each of the aforementioned multiple power transmission modules is configured to communicate with the power receiving device for distance measurement, The device further comprises an information presentation device (4) for presenting information to a person present in the aforementioned target space, The control unit, By communicating with the power receiving device, status information including the remaining power of the power receiving device is obtained. By having the multiple power transmission modules perform distance measurement communication with the power receiving device, distance data, which is data indicating the distance from the multiple power transmission modules to the power receiving device, is obtained. Based on the distance data, the device position, which is the position of the power receiving device within the target space, is obtained. The wireless power transmission system according to claim 1, wherein if the remaining power of the power receiving device is less than a predetermined value and the device is located outside a predetermined recommended position, the system is configured to perform a suggestion process using the information display device to suggest placing the power receiving device in the recommended position.

12. The wireless power transmission system according to claim 11, wherein the recommended position is a position where two or three power transmission modules can be charged in parallel.

13. A power transmission module for wirelessly charging a power receiving device located within a target space, An antenna (21) configured to transmit charging radio waves, which are radio waves used for charging, A power transmission circuit (22) for transmitting the charging radio waves from the antenna, A communication circuit (23) for communicating with a controller that controls the wireless charging of the power receiving device, The system includes a wireless control unit (24) that controls the power transmission circuit based on data received from the controller via the communication circuit, The wireless control unit, The antenna is configured to enable data communication with the power receiving device. Based on instructions from the controller, the power transmission circuit is used to transmit the charging radio waves from the antenna, The controller receives feedback data indicating the received power transmitted from the power receiving device and provides it to the controller. A power transmission module configured to adjust the transmission settings of the charging radio waves based on a signal input from the controller.

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