Power transmission device, method performed by power transmission device, and program

Abstract

This power transmission device 100 includes: a first power transmission coil 303; a second power transmission coil 307 disposed inside the second power transmission coil 303; and a power transmission unit 302 that applies a power signal of a first frequency using at least the first power transmission coil 303 and applies a power signal of a second frequency using the second power transmission coil 307.

Description

Power transmission device, method and program performed by the power transmission device

[0001] The present disclosure relates to wireless power transfer.

[0002] The wireless charging standard (WPC standard) established by the Wireless Power Consortium (WPC) is widely known. Patent Document 1 (JP-A-2005-102666) discloses a technology for mounting a first coil and a second coil smaller than the first coil in a power transmitting device.

[0003] JP 2017-93174 A

[0004] No suitable configuration has been proposed for a power transmission device equipped with multiple coils.

[0005] The present disclosure provides a technique for appropriately transmitting power wirelessly.

[0006] A power transmission device according to one aspect of the present disclosure includes a first coil, a second coil arranged inside the first coil, and power transmission means that applies a power signal of a first frequency using at least the first coil and applies a power signal of a second frequency higher than the first frequency using the second coil.

[0007] According to the present disclosure, wireless power transmission can be performed appropriately.

[0008] Fig. 1 is a diagram illustrating a configuration example of a power receiving device. Fig. 2 is a diagram illustrating a configuration example of a power transmitting device. Fig. 3 is a diagram illustrating a configuration example of a power transmitting device. Fig. 4 is a flowchart illustrating processing of a power transmitting device. Fig. 5 is a sequence diagram illustrating operations of a power transmitting device and a power receiving device in this embodiment. Fig. 6 is a diagram illustrating another configuration example of a power transmitting device.

[0009] <Embodiments> Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0010] (System Configuration) A diagram showing an example of the configuration of a wireless power transmission system according to the present embodiment. The diagram shows an example of the configuration of a wireless power transmission system according to the present embodiment. In one example, the wireless power transmission system includes a power transmission device 100 and a power receiving device 101. The power transmission device 100 and the power receiving device 101 comply with standards established by the Wireless Power Consortium (WPC) (hereinafter referred to as the WPC standard). The power transmission device 100 is, for example, an electronic device that wirelessly transmits power to a power receiving device 101 placed thereon. The power transmission device 100 wirelessly transmits power to the power receiving device 101 via a power transmission coil. The power receiving device 101 is, for example, an electronic device that receives power from the power transmission device 100 and charges a built-in battery.

[0011] 1 shows an example of the configuration of a power receiving device 101. The power receiving device 101 includes, for example, a control unit 200, a power receiving coil 201, a rectification unit 202, a voltage control unit 203, a communication unit 204, a charging unit 205, a battery 206, a resonance capacitor 207, and a switch 208.

[0012] The control unit 200 controls the entire power receiving device 101. The control unit 200 includes one or more processors, such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The control unit 200 may include one or more storage devices, such as a RAM (Random Access Memory) or a ROM (Read Only Memory). The control unit 200 may be configured to execute each process described below by, for example, executing a program stored in the storage device using the processor.

[0013] The receiving coil 201 is a coil used when receiving power from a power transmitting coil of the power transmitting device 100, which will be described later. The receiving coil 201 is also connected to a resonant capacitor 207 and configured to resonate at a specific frequency F2. The switch 208 is a switch for shorting the receiving coil 201 and the resonant capacitor 207, and is controlled by the control unit 200. When the switch 208 is turned on, the receiving coil 201 and the resonant capacitor 207 form a series resonant circuit. At this time, current flows only through the closed circuit of the receiving coil 201, the resonant capacitor 207, and the switch 208, and no current flows through the rectifier unit 202 or the voltage control unit 203, which will be described later. On the other hand, when the switch 208 is turned off, current flows through the rectifier unit 202 and the voltage control unit 203 via the receiving coil 201 and the resonant capacitor 207.

[0014] The rectifier 202 converts the AC voltage and AC current received via the power receiving coil 201 into a DC voltage and DC current.

[0015] Voltage control unit 203 converts the level of the DC voltage input from rectification unit 202 into a DC voltage level (neither too high nor too low) suitable for operation of control unit 200, charging unit 205, etc. Furthermore, voltage control unit 203 supplies the voltage of the converted level to charging unit 205.

[0016] The charging unit 205 charges the battery 206 of the electronic device 102 with the voltage supplied from the voltage control unit 203 .

[0017] The communication unit 204 performs control communication for wireless charging based on the WPC standard with the power transmitting device 100. This control communication is performed by load modulating the AC voltage and AC current received by the power receiving coil 201.

[0018] 2A shows a configuration example of the power transmitting device 100. The power transmitting device 100 includes, for example, a control unit 300, a power supply unit 301, a power transmitting unit 302, a first power transmitting coil 303, a second power transmitting coil 307, a communication unit 304, a memory 305, a first resonant capacitor 306, a second resonant capacitor 308, and a switch 307.

[0019] The control unit 300 controls the entire power transmitting device 100. The control unit 300 includes one or more processors, such as a CPU or an MPU. The control unit 300 can be configured to perform each process described below by, for example, using the processor to execute a program stored in a memory 305 (described below) or a storage device built into the control unit 300.

[0020] The power supply unit 301 supplies power to each functional block. The power supply unit 301 is, for example, a commercial power supply or a battery. The battery can store power supplied from the commercial power supply, for example.

[0021] The power transmitting unit 302 converts DC or AC power input from the power supply unit 301 into AC power in a frequency band used for wireless power transmission, inputs the AC power to the power transmitting coil 303, and causes the power transmitting coil 303 to generate electromagnetic waves for receiving power at the power receiving device 101. For example, the power transmitting unit 302 converts the DC voltage supplied from the power supply unit 301 into an AC voltage using a half-bridge or full-bridge switching circuit using FETs (Field Effect Transistors). In this case, the power transmitting unit 302 includes a gate driver that controls the ON / OFF of the FETs. The power transmitting unit 302 also controls the intensity and frequency of the electromagnetic waves to be output by adjusting at least one of the voltage (transmission voltage) and current (transmission current) input to the power transmitting coil 303, or the frequency. For example, the power transmitting unit 302 increases the intensity of the electromagnetic waves by increasing the transmission voltage or current, and decreases the intensity of the electromagnetic waves by decreasing the transmission voltage or current. Here, the power transmitting unit 302 is assumed to be capable of supplying at least 15 watts (W) of power to the charging unit 205 of the power receiving device 101 that complies with the WPC standard. Based on instructions from the control unit 300, the power transmitting unit 302 controls the output of AC power so that the output of electromagnetic waves from the power transmitting coil 303 is started or stopped. The transmission voltage or current frequency generated by the power transmitting unit 302 may be a frequency between 110 kHz and 148.5 kHz used in the WPC standard, or 360 kHz, 1.7 MHz, or the like.

[0022] The communication unit 304 communicates with the power receiving device 101 via the first power transmitting coil 303 or the second power transmitting coil 307 for power transmission control based on the WPC standard. The communication unit 304 modulates the AC voltage and AC current output from the power transmitting unit 302 using frequency modulation (FSK (Frequency Shift Keying)), and transmits information to the power receiving device 101. The communication unit 304 also demodulates the AC voltage and AC current modulated by load modulation by the communication unit 204 of the power receiving device 101, and acquires information transmitted by the power receiving device 101. That is, the communication unit 304 superimposes information to be transmitted to the power receiving device 101 on electromagnetic waves transmitted from the power transmitting unit 302, and communicates with the power receiving device 101 by detecting a received signal superimposed by the power receiving device 101 on the electromagnetic waves. The communication unit 304 may communicate with the power receiving device 101 according to a standard different from the WPC standard by using a coil (or antenna) different from the power transmitting coil 303. The communication unit 304 may communicate with the power receiving device 101 by selectively using a plurality of communication functions.

[0023] The memory 305 stores, for example, a control program executed by the control unit 300 and information such as the states of the power transmitting device 100 and the power receiving device 101. For example, the state of the power transmitting device 100 is acquired by the control unit 300. The state of the power receiving device 101 is acquired by the control unit 200 of the power receiving device 101 and transmitted from the communication unit 205, and the power transmitting device 100 acquires information indicating this state via the communication unit 304.

[0024] The first power transmitting coil 303 is connected to a first resonant capacitor 306 and configured to resonate at a specific frequency F1. The second power transmitting coil 307 is connected to a second resonant capacitor 308 and configured to resonate at a specific frequency F3.

[0025] The configurations of the first power transmitting coil 303 and the second power transmitting coil 307 will now be described with reference to FIG. 2B . FIG. 2B is a top view of the two coils. The first power transmitting coil 303 and the second power transmitting coil 307 are arranged substantially concentrically. This means that the centers of the first power transmitting coil 303 and the second power transmitting coil are located at substantially the same point. The outer diameter of the second power transmitting coil 307 is smaller than the inner diameter of the first power transmitting coil 303. Note that the hatched area in FIG. 2B indicates the area of ​​the coil, and the number of turns of the coil may be one or more. Furthermore, the centers of the first power transmitting coil 303 and the second power transmitting coil 307 do not need to be located at substantially the same point, but the second power transmitting coil 307 is arranged inside the first power transmitting coil 303.

[0026] Furthermore, the inductance value of the second power transmitting coil 307 is assumed to be smaller than the inductance value of the first power transmitting coil 303. Here, the resonant frequency F1 of the first power transmitting coil 303 and the first resonant capacitor 306 is assumed to be in the 100 kHz band, and the resonant frequency F3 of the second power transmitting coil 307 and the second resonant capacitor 308 is assumed to be in the 300 kHz band.

[0027] When transmitting power via the first power transmitting coil 303, the power transmitting unit 302 applies an AC voltage or current with a frequency in the 100 kHz band (100 kHz to 148.5 kHz) to the first power transmitting coil 303. On the other hand, when transmitting power via the second power transmitting coil 307, the power transmitting unit 302 applies an AC voltage or current with a frequency in the 300 kHz band (330 kHz, 360 kHz, etc.) to the second power transmitting coil 307. In other words, the frequency of the power signal applied using the second power transmitting coil 307 is higher than the frequency of the power signal applied using the first power transmitting coil 303.

[0028] Furthermore, because the inductance value of the second power transmitting coil 307 is smaller than the inductance value of the first power transmitting coil 303, the second power transmitting coil 307 can be made smaller than the first power transmitting coil 303, and the second power transmitting coil 307 can be arranged inside the first power transmitting coil 303. Therefore, the two coils of the power transmitting device 100 are arranged substantially concentrically, and the power transmitting device 100 can be made smaller.

[0029] Furthermore, the power receiving coil 201 of the power receiving device 101 has approximately the same size and inductance value as the second power transmitting coil 307, and the resonant frequency F2 of the power receiving coil 201 and the resonant capacitor 207 is in the 300 kHz band (330 kHz, 360 kHz, etc.).

[0030] It is assumed that the power receiving coil of a power receiving device (not shown) has substantially the same size and inductor value as the second power transmitting coil 303, and the resonant frequency of the power receiving coil and the resonant capacitor is in the 100 kHz band. The power transmitting device 100 transmits power to the power receiving device using an appropriate power receiving coil. That is, the power transmitting device 100 transmits power to the power receiving device 101 having a resonant frequency in the 300 kHz band using the second power transmitting coil 307. On the other hand, the power transmitting device 100 transmits power to the power receiving device having a resonant frequency in the 100 kHz band using the first power transmitting coil 303. This power receiving device (not shown) has the same configuration as that described in FIG. 1 , but differs from the power receiving device 101 of FIG. 1 in that it has substantially the same size and inductor value as the second power transmitting coil 303. The power transmitting device 100 transmits power to any of these power receiving devices.

[0031] Furthermore, the frequency of the electromagnetic waves transmitted by the power transmitting device 100 is not limited to the 100 kHz band or the 300 kHz band, but may be in the 60 kHz to 90 kHz band, the 1.7 MHz band, the 6.78 MHz band, or the 13.56 MHz band.

[0032] 4 is a flowchart illustrating processing by the power transmitting device 100 of this embodiment. The power transmitting device 100 of this embodiment transmits Analog Pings alternately from the first power transmitting coil 303 and the second power transmitting coil 307. The Analog Pings are short-duration power signals applied by the power transmitting device 100 to detect the presence of an object without activating the power receiving device 101.

[0033] First, the power transmitting device 100 sets the operating frequency of the power transmitting unit 302 to the 100 kHz band (S500), and applies an Analog Ping via the first power transmitting coil 303 (s501). The power of the Analog Ping is so small that even if the power receiving device 101 receives this power, it cannot activate the power receiving device 101 (specifically, the control unit 200). The power transmitting device 100 detects an object by using the Analog Ping to detect a shift in the resonant frequency of the voltage or current of the power transmitting coil 303, or a change in the voltage or current flowing through the power transmitting coil 303, due to the object being present near the power transmitting coil 303. Specifically, the power transmitting device 100 determines that an object has been detected when a physical quantity, such as a resonant frequency shift or a change in the voltage or current, exceeds a threshold value.

[0034] If an object is not detected (NO in S502), the power transmitting device 100 changes the power transmitting coil and the operating frequency (S508). Because the first power transmitting coil 303 is used and the operating frequency of the power transmitting unit 302 is in the 100 kHz band, the power transmitting device 100 uses the second power transmitting coil 307, changes the operating frequency of the power transmitting coil 307 to the 300 kHz band, and applies Analog Ping.

[0035] If an object is detected (YES in S502), a Digital Ping is applied using the same power transmitting coil and operating frequency (S503). The Digital Ping is a power signal applied by the power transmitting device 100 for the purpose of starting up the power receiving device. Therefore, the power of the Digital Ping is power for starting up the power receiving device 101 (specifically, the control unit 200) and is greater than the power of the Analog Ping. The Digital Ping is subsequently applied continuously. The power transmitting device 100 continues to apply a power signal equal to or greater than the Digital Ping from the time it starts applying the Digital Ping until it receives an EPT (End Power Transfer) data packet (described later) from the power receiving device 101.

[0036] When the power receiving device 101 is activated by a Digital Ping, it stores the voltage value of the applied Digital Ping in a Signal Strength data packet and transmits it to the power transmitting device 100. The Signal Strength data packet is a response to the Digital Ping. Therefore, if the power transmitting device 100 receives a Signal Strength data packet in response to the Digital Ping, it can determine that the detected object is the power receiving device 101. Note that the data stored in the Signal Strength data packet may be data related to a measurable coupling-dependent quantity inside the power receiving device 101. This coupling-dependent quantity is, for example, a rectified voltage, which is the output voltage of the rectifier 202, an open-circuit voltage, or a received power level.

[0037] Since the resonant frequency of the power receiving coil 201 and resonant capacitor 207 of the power receiving device 101 is 300 kHz, the power receiving device 101 is not activated by a digital ping in the 100 kHz band but is activated by a digital ping in the 300 kHz band. Then, the power receiving device 101 transmits to the power transmitting device 100 a signal strength data packet obtained by load-modulating the digital ping in the 300 kHz band.

[0038] When the power transmitting device 100 receives the Signal Strength data packet (YES in S504), it determines to transmit power using the power transmission method and operating frequency used for applying the Analog Ping and Digital Ping immediately before (S505). That is, if the results of S502 and S504 are YES, the power transmitting device 100 determines to transmit power using the second power transmitting coil 303 and an operating frequency in the 100 kHz band. On the other hand, if the results of S502 are NO and, after S508, the power transmitting device 100 determines to transmit power using the first power transmitting coil 307 and an operating frequency in the 300 kHz band. Then, it stops the detection process for the power receiving device using the Analog Ping and Digital Ping by the other coil (S509).

[0039] If the power transmitting device 100 has not received a Signal Strength data packet (NO in S504), it determines whether it has attempted object detection (power receiving device detection) in all frequency bands supported by the power transmitting unit and power transmitting coil (S506). If object and power receiving device detection using Analog Ping and Digital Ping in the 100 kHz and 300 kHz bands has not been performed (NO in S506), the power transmitting device 100 changes the power transmitting coil and operating frequency (S508). If object and power receiving device detection using Analog Ping and Digital Ping in the 100 kHz and 300 kHz bands has been performed (YES in S506), the power transmitting device 100 determines that the detected object is a foreign object. Then, the power transmitting device 100 issues an error notification (S507).

[0040] (Operations of the power transmitting device 100 and the power receiving device 101) Fig. 4 is a sequence diagram illustrating the operations of the power transmitting device 100 and the power receiving device 101 according to this embodiment. That is, the following description will be given taking as an example a case where the power receiving device 101 is placed on the power transmitting device 100. Note that the numbers in parentheses in Fig. 4 indicate the operating frequency. That is, (100) indicates that the operating frequency is in the 100 kHz band, and (300) indicates that the operating frequency is in the 300 kHz band.

[0041] The power transmitting device 100 applies an Analog Ping at an operating frequency of 100 kHz using the first power transmitting coil 303 (F400). Since no object is detected, the power transmitting device 100 then applies an Analog Ping at an operating frequency of 300 kHz using the second power transmitting coil 307 (F401). After this, it is assumed that the power receiving device 101 is placed on the power transmitting device 100 (F402).

[0042] The power transmitting device 100 again transmits an Analog Ping in the 100 kHz band using the first power transmitting coil 303 (F403). In this case, the power transmitting device 100 applies a Digital Ping in the 100 kHz band using the first power transmitting coil 303 to detect an object (F404). However, the power receiving device 101 does not start up because the resonant frequency of the power receiving coil 201 and the resonant capacitor 207 is in the 300 kHz band, and therefore cannot respond to the Digital Ping.

[0043] The power transmitting device 100 does not receive the Signal Strength data packet, but does not issue an error notification because Analog Ping has not yet been applied in all frequency bands. In other words, this is because the object detected by F403 may be a power receiving device that responds to Digital Ping using the second power transmitting coil 307.

[0044] The power transmitting device 100 applies an Analog Ping in the 300 kHz band using the second power transmitting coil 307 (F405). Then, the power transmitting device 100 applies a Digital Ping in the 300 kHz band using the second power transmitting coil 307 to detect an object (F406).

[0045] The power receiving device 101 is activated because the resonant frequency of the power receiving coil 201 and the resonant capacitor 207 is in the 300 kHz band, and transmits a Signal Strength data packet to the power transmitting device 100 in the 300 kHz band (F407). Next, the power receiving device 101 transmits an ID data packet storing an ID including version information of the WPC standard and a device identifier to the power transmitting device 100 (F408). Thereafter, the battery 206 is charged with the received power through operation compliant with the WPC standard. The power transmitting device 100 also determines the operating frequency to be used for transmitting power to the power receiving device 101 to be the 300 kHz band, and determines the second power transmitting coil 307 to be the power transmitting coil to be used for power transmission.

[0046] Then, when charging is completed, the power transmitting device 100 transmits an EPT data packet requesting the power transmitting device 100 to stop power transmission (F409).

[0047] As described above, the power transmitting device 100 does not immediately determine that a foreign object exists even if it does not receive a Signal Strength data packet in response to a Digital Ping using the first power transmitting coil 303. The power transmitting device 100 can then detect the power receiving device 101 by applying a Digital Ping using the second power transmitting coil 307.

[0048] <Modification 1> In the present embodiment, the first power transmitting coil and the second power transmitting coil 307 are described as separate bodies, but this is not limiting. For example, the power transmitting device 102 may have a configuration as shown in Fig. 5. In Fig. 5, the same reference numerals as those in Figs. 2A and 2B will not be described.

[0049] The switch 309 is a switch that connects or disconnects the first power transmitting coil 303 and the second power transmitting coil 307 in series. The switch 311 is a switch that connects or disconnects the second power transmitting coil 307 and the second resonant capacitor 308 or the power transmitting unit 302. The switches 309 and 311 and the inverter 310 are controlled by the control unit 300.

[0050] When transmitting power in the 300 kHz band, the control unit 300 controls the switch 311 to be turned ON. This turns OFF the switch 309 via the inverter 310, disconnects the first power transmitting coil 312 and the second power transmitting coil 307, and applies a voltage from the power transmitting unit 302 to both ends of the second power transmitting coil 307. As in FIG. 2A , the second power transmitting coil 307 alone operates at an operating frequency in the 300 kHz band.

[0051] On the other hand, when transmitting power in the 100 kHz band, the control unit 300 controls the switch 311 to be turned OFF. This turns ON the switch 309 via the inverter 310, connecting the first power transmitting coil 312 and the second power transmitting coil 303 in series, and applying a voltage from the power transmitting unit 302 to one end of the first power transmitting coil 312 and one end of the second power transmitting coil 307. The first power transmitting coil 312, the second power transmitting coil 307, and the first resonant capacitor 306 then form a resonator, and the first power transmitting coil 312 can be configured so that the resonant frequency of the resonator operates in the 100 kHz band. This allows the first power transmitting coil 303 to be reduced in size. The reason for this is explained in detail below.

[0052] Let L1 be the inductance value of the power transmitting coil required to transmit power in the 100 kHz band, and L2 be the inductance value of the power transmitting coil required to transmit power in the 300 kHz band. The first power transmitting coil 303 in FIG. 2A has an inductance value of L1. Here, the first power transmitting coil 312 in FIG. 5 has an inductance value of L1-L2, which is smaller than the inductance value of the first power transmitting coil 303 in FIG. 2A. Because the inductance value is proportional to the number of turns, the first power transmitting coil 312 in FIG. 5, which has a smaller inductance value, can be made smaller than the first power transmitting coil 303 in FIG. 2A.

[0053] <Modification 2> In the above-described embodiment, the first power transmitting coil 303 and the second power transmitting coil 307 are used to apply the analog ping and the digital ping without overlapping in time. However, the analog ping or the digital ping using the first power transmitting coil 303 and the analog ping or the digital ping using the second power transmitting coil 307 may be applied so as to overlap in time. This is because the power transmitting device 100 can determine which digital ping the power receiving device 101 has transmitted the signal strength data packet to by demodulating the packet. For example, if the packet is modulated at a frequency in the 300 kHz band, the communication unit that receives the packet using the second power transmitting coil 307, which has a resonant frequency in the 300 kHz band, can demodulate the packet.

[0054] <Modification 3> Although the present embodiment has been described with respect to a case where there are two power transmitting coils, there may be N (N is an integer equal to or greater than 3) power transmitting coils. In this case, the power transmitting coils are arranged in ascending order of operating frequency, namely, the first power transmitting coil, ..., the (N-1)th power transmitting coil, and the Nth power transmitting coil. In this case, the outer diameter of the Nth power transmitting coil may be smaller than the inner diameter of the (N-1)th power transmitting coil.

[0055] Furthermore, the maximum transmittable power may decrease in the order of the first power transmitting coil, ..., the (N-1)th power transmitting coil, and the Nth power transmitting coil. For example, the maximum power of the first power transmitting coil may be greater than 15 watts and equal to or less than 25 watts (or 50 watts), the maximum power of the second power transmitting coil may be 15 watts, and the maximum power of the third power transmitting coil may be less than 15 watts (e.g., 2.5 watts, 5 watts, or 7.5 watts).

[0056] Furthermore, the N coils may be configured to be connectable and disconnectable by switches, as shown in FIG.

[0057] The present disclosure can also be realized by a process in which a program that realizes one or more functions of the embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present disclosure can also be realized by a circuit (e.g., an ASIC) that realizes one or more functions.

[0058] Furthermore, for example, the power receiving device may have some or all of the processes to be executed by the power transmitting device and the functions of the power transmitting device described in this specification, or the power transmitting device may execute some or all of the processes to be executed by the power receiving device and the functions of the power receiving device.

[0059] The power transmitting device and the power receiving device may be, for example, an image input device such as an imaging device (still camera, video camera, etc.) or a scanner, or an image output device such as a printer, copier, or projector. They may also be storage devices such as hard disk drives or memory devices, or information processing devices such as personal computers (PCs), smartphones, tablet devices, and laptops. The power transmitting device and the power receiving device may also be automobiles, robots, medical equipment, printers, etc.

[0060] The power receiving device of the present disclosure may also be an information terminal device. For example, the information terminal device has a display unit (display) that receives power from a power receiving antenna and displays information to a user. The power received from the power receiving antenna is stored in a power storage unit (battery), and power is supplied from the battery to the display unit. In this case, the power receiving device may have a communication unit that communicates with another device different from the power transmitting device. The communication unit may be compatible with communication standards such as NFC communication and the fifth generation mobile communication system (5G).

[0061] The power receiving device of the present disclosure may also be a vehicle such as an automobile. For example, the automobile serving as the power receiving device may receive power from a charger (power transmitting device) via a power transmitting antenna installed in a parking lot. The automobile serving as the power receiving device may also receive power from the charger (power transmitting device) via a power transmitting antenna embedded in the road. Such an automobile supplies the received power to a battery. The battery's power may be supplied to a driving unit (motor, electric unit) that drives the wheels, or may be used to drive a sensor used for driving assistance or a communication unit that communicates with an external device. In other words, in this case, the power receiving device may include, in addition to the wheels, a battery, a motor or sensor that is driven using the received power, and even a communication unit that communicates with devices other than the power transmitting device. Furthermore, the power receiving device may have a storage unit for accommodating a person. For example, the sensor may be a sensor used to measure the distance between vehicles or the distance to other obstacles. The communication unit may be compatible with, for example, the Global Positioning System (GPS), or may be compatible with a communication standard such as the fifth generation mobile communication system (5G). The vehicle may be a bicycle or a motorcycle.

[0062] The power receiving device of the present disclosure may also be an electric tool, a home appliance, etc. These devices, which are power receiving devices, may have a battery and a motor that is driven by the received power stored in the battery. These devices may also have a notification means for notifying the user of the remaining battery charge, etc.

[0063] Furthermore, these devices may have a communication unit that communicates with other devices other than the power transmitting device.

[0064] The communication unit may be compatible with communication standards such as NFC and the fifth generation mobile communication system (5G).

[0065] The power transmitting device of the present disclosure may also be an in-vehicle charger that transmits power to a mobile information terminal device, such as a smartphone or tablet, that supports wireless power transmission within an automobile.

[0066] Such an on-board charger may be installed anywhere in the vehicle. For example, the on-board charger may be installed in the console of the vehicle, on the instrument panel (instrument panel, dashboard), between passenger seats, on the ceiling, or in the door. However, it is best not to install it in a location that interferes with driving. Also, while the power transmission device has been described using the example of an on-board charger, such a charger is not limited to being installed in a vehicle, but may also be installed in transportation such as a train, airplane, or ship. In this case, the charger may also be installed between passenger seats, on the ceiling, or in the door.

[0067] The power transmitting device may also be a vehicle such as an automobile equipped with an on-board charger. In this case, the power transmitting device has wheels and a battery, and supplies power to the power receiving device via a power transmitting circuit unit and a power transmitting antenna using power from the battery.

[0068] The present disclosure can also be realized by a process in which a program that realizes one or more functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present disclosure can also be realized by a circuit (e.g., an ASIC) that realizes one or more functions.

[0069] In addition, some of the processes described with reference to the flowcharts in this disclosure may be implemented by hardware. For example, a specific compiler may be used to automatically generate a dedicated circuit on an FPGA from a program for implementing each step. Alternatively, a gate array circuit may be formed in the same manner as an FPGA and implemented as hardware.

[0070] <Others> The disclosure of the above-described embodiment includes the following configurations, methods, and programs.

[0071] (Configuration 1) A power transmission device having: a first coil; a second coil arranged inside the first coil; and power transmission means that applies a power signal of a first frequency using at least the first coil, and applies a power signal of a second frequency higher than the first frequency using the second coil.

[0072] (Configuration 2) The power transmitting device according to Configuration 1, wherein the power signal of the first frequency is applied using the first coil and the second coil, and the power signal of the second frequency is applied using only the second coil.

[0073] (Configuration 3) The power transmitting device according to Configuration 1, wherein the power signal of the first frequency is applied using only the first coil, and the power signal of the second frequency is applied using only the second coil.

[0074] (Configuration 4) The power transmitting device according to any one of Configurations 1 to 3, wherein the first coil and the second coil are arranged substantially concentrically.

[0075] (Configuration 5) The power transmitting device according to any one of configurations 1 to 4, wherein the power transmitting means applies a power signal that activates the power receiving device at each of the first frequency and the second frequency, and further includes a determination means that determines that a foreign object is present if there is no specific response from the power receiving device to either of the power signals that activate the power receiving device applied at each of the first frequency and the second frequency.

[0076] (Configuration 6) The power transmitting device according to configuration 5, wherein the specific response is a Signal Strength data packet.

[0077] (Configuration 7) The power transmission device described in any one of configurations 1 to 6, wherein the power transmission means applies a power signal that activates the power receiving device at at least one of the first frequency and the second frequency, and when there is a specific response from the power receiving device to the power signal that activates the power receiving device, the power transmission means transmits power to the power receiving device at the frequency at which there was a specific response from the power receiving device.

[0078] (Configuration 8) The power transmitting device according to Configuration 3, wherein the power transmitting means applies a power signal that activates the power receiving device at at least one of the first frequency and the second frequency, and when there is a specific response from the power receiving device to the power signal that activates the power receiving device, the power transmitting means transmits power to the power receiving device at the frequency at which there is a specific response from the power receiving device, and controls so as not to apply a power signal that detects an object at the other frequency.

[0079] (Method 1) A method performed by a power transmitting device, which applies a power signal to start up a power receiving device at a first frequency, applies a power signal to start up a power receiving device at a second frequency higher than the first frequency, and determines that a foreign object is present if there is no specific response from the power receiving device to either the power signal to start up the power receiving device applied at the first frequency or the second frequency.

[0080] (Program) A program that causes a computer to execute the method described in Method 1.

[0081] The present invention is not limited to the above-described embodiments, and various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, the following claims are appended to apprise the public of the scope of the present invention.

[0082] This application claims priority based on Japanese Patent Application No. 2024-073063, filed April 26, 2024, the entire contents of which are incorporated herein by reference.

Claims

1. A power transmission device comprising: a first coil; a second coil disposed inside the first coil; and power transmission means for applying a power signal of a first frequency using at least the first coil, and for applying a power signal of a second frequency higher than the first frequency using the second coil.

2. The power transmitting device according to claim 1, wherein the power signal of the first frequency is applied using the first coil and the second coil, and the power signal of the second frequency is applied using only the second coil.

3. The power transmitting device according to claim 1, wherein the power signal of the first frequency is applied using only the first coil, and the power signal of the second frequency is applied using only the second coil.

4. The power transmission device according to claim 1, wherein the first coil and the second coil are arranged substantially concentrically.

5. The power transmission device according to claim 1, wherein the power transmission means applies a power signal to activate the power receiving device at each of the first frequency and the second frequency, and further comprises a determination means for determining that a foreign object is present if there is no specific response from the power receiving device to either of the power signals to activate the power receiving device applied at each of the first frequency and the second frequency.

6. The power transmitting device according to claim 5, wherein the specific response is a Signal Strength data packet.

7. The power transmission device according to claim 1, wherein the power transmission means applies a power signal to activate the power receiving device at at least one of the first frequency and the second frequency, and when there is a specific response from the power receiving device to the power signal to activate the power receiving device, the power transmission means transmits power to the power receiving device at the frequency at which there is a specific response from the power receiving device.

8. The power transmission device according to claim 3, wherein the power transmission means applies a power signal at at least one of the first frequency and the second frequency to activate the power receiving device, and when there is a specific response from the power receiving device to the power signal to activate the power receiving device, the power transmission means transmits power to the power receiving device at the frequency at which the specific response was received from the power receiving device, and controls so as not to apply a power signal for detecting an object at the other frequency.

9. A method performed by a power transmitting device, comprising: applying a power signal at a first frequency to activate a power receiving device; applying a power signal at a second frequency higher than the first frequency to activate the power receiving device; and determining that a foreign object is present if there is no specific response from the power receiving device to either the power signal applied at the first frequency or the power signal applied at the second frequency to activate the power receiving device.

10. A program for causing a computer to execute the method of claim 9.

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