Wireless power supply system

Abstract

Provided is a wireless power supply system capable of wirelessly supplying power without requiring adjustment of the positions and angles of a power transmission-side coil and a power reception-side coil for an artificial device mounted inside a human body and without interruption even if the positions and angles of the power transmission-side coil and the power reception-side coil are slightly shifted. In a wireless power supply system using PT symmetry for supplying power from an external device (19) provided outside the human body to an internal device (29) provided inside the human body for driving an artificial device, a power transmission-side resonant circuit (12) is formed by connecting a power transmission-side coil (11) and a power transmission-side resonant capacitor in series. A power-receiving-side resonant circuit (22) is formed by connecting a power-receiving-side coil (21) to at least one power-receiving-side resonant capacitor, and the resonant frequencies of both the power-transmitting-side and power-receiving-side resonant circuits are set so as to coincide with each other.

Description

Technical Field

[0001] The present invention relates to a wireless power supply system for supplying power to artificial devices such as an artificial heart installed inside a human body. Background Art

[0002] Currently, artificial devices such as an auxiliary artificial heart that assists blood circulation by installing a pump (electric pump) driven by a motor under the patient's heart are gradually becoming practical. However, in this case, as a power source (electricity) for driving the electric pump, a hole is usually opened in the abdomen (human body) to lead wires out of the body, and the wires are connected to the power source or to a control device outside the body (a control device for controlling the drive of the electric pump) to operate the auxiliary artificial heart (for example, refer to Patent Document 1, etc.).

[0003] However, since holes are opened in the abdomen (human body) for passing wires, etc., there are various problems such as the patient being unable to take a bath or the risk of infection increasing. Therefore, it is hoped that wireless power supply technology that allows electric power to flow (supply power) without contact can be applied to artificial devices installed inside the human body.

[0004] In addition, if the patient is an adult, he or she can take care of the holes through which the wires for the artificial devices installed inside the human body pass, and can move carefully. However, in the case of a child patient, special attention must be paid to the care of the hole, and the risk of infection will also increase. Therefore, it is more desirable to apply wireless power supply technology that allows electricity to flow (supply power) without contact without opening a hole in the abdomen (human body) to artificial devices such as auxiliary artificial hearts.

[0005] On the other hand, there are many known non-contact wireless power supply technologies, such as electromagnetic induction technology and magnetic field resonance technology. Among them, electromagnetic induction wireless power supply technology is used, for example, in charging mobile phones. The coils are arranged up and down, which is the transfer of power itself. When the power transmission side coil and the power receiving side coil are tightly connected, power will flow.

[0006] However, electromagnetic induction wireless power supply technology cannot increase the distance between the power transmitting coil and the power receiving coil. In addition, charging and power supply cannot be performed when the positions of the power transmitting coil and the power receiving coil are slightly deviated or separated. Therefore, there is a problem that it is difficult to apply to artificial devices installed inside the human body, such as artificial hearts.

[0007] In addition, the wireless power supply technology of the magnetic field resonance method was developed by a university in the United States around 2006-2007. Compared with the electromagnetic induction method, the distance between the power transmission side coil and the power receiving side coil can be increased, so it has become close to the level of practical application. However, there is a sensitivity problem, that is, if the distance between the power transmission side coil and the power receiving side coil is not fixed, the power cannot be transmitted. Whether it is closer or farther than this distance, or at a slightly offset angle, it cannot be transmitted. Therefore, in this regard, there is also a problem that it is difficult to apply to artificial devices installed in the human body, such as artificial hearts.

[0008] Therefore, in order to solve this problem, for example, Patent Document 2 discloses a contactless power supply system, which, in a wireless power supply technology of a magnetic field resonance method, has a control device, which has the function of adjusting the positional relationship and angle of the power transmitting side coil and the power receiving side coil, thereby supplying stable power to an artificial heart, etc.

[0009] [Prior art literature]

[0010] [Patent Document]

[0011] [Patent Literature ] Japanese Patent Publication No. 2020-14497

[0012] [Patent Literature ]International Patent Publication No. 2018 / 150678

[0013] [Patent Literature ] Japanese Patent Publication No. 2022-121324

[0014] [Non-patent literature]

[0015] [Non-patent document 1] Sid Assawaworrarit, Xiaofang Yu & Shanhui Fan, “Robust wireless power transfer using a nonlinear parity-time-symmetric circuit”, Nature, 15 JUNE 2017, volume 546, p.387-390 Summary of the invention

[0016] [Summary of the Invention]

[0017] [Problems to be solved by the invention]

[0018] However, in a non-contact power supply system based on a magnetic field resonance method such as that shown in Patent Document 2, it is necessary to have a function of adjusting the distance between the power transmission side coil and the power reception side coil to be constant or adjusting the angle to be constant, so that external devices such as external power transmission side devices become large, and it is necessary to continuously perform high-level control such as the positional relationship and angle adjustment between the coils, so there is a problem of placing a burden on the control unit of the external power transmission side device. In addition, there is also a problem that this high-level control function stops when the battery is replaced.

[0019] The present invention is made to solve the above-mentioned problems, and its purpose is to provide a wireless power supply system that does not require adjustment and control of the position and angle of the power transmitting side coil and the power receiving side coil for an artificial device installed inside the human body, and can wirelessly supply power without interruption even if the position and angle of the power transmitting side coil and the power receiving side coil are slightly deviated.

[0020] [Solution to solve the problem]

[0021] In order to achieve the above-mentioned purpose, the present invention provides a wireless power supply system, which is characterized in that it utilizes the Parity-Time symmetry and comprises: an internal device arranged inside the human body, which drives the artificial device arranged inside the human body; and an external device arranged outside the human body, which supplies power to the internal device from the external device in a non-contact manner, and the external device is provided with: an inverter circuit, which is connected to an external power supply and converts the DC voltage supplied from the external power supply into an AC voltage; and a power transmission side resonance circuit and a power transmission side coil, which convert the AC voltage converted by the inverter circuit into an AC magnetic field and transmit power to the internal device, The internal device is provided with: a receiving-side coil and a receiving-side resonant circuit, which interlink the AC magnetic field generated by the transmitting-side coil; and a rectifier circuit, which converts the AC voltage output from the receiving-side coil and the receiving-side resonant circuit into a DC voltage. The internal device drives the artificial device using the DC power converted by the rectifier circuit. The transmitting-side resonant circuit is formed by connecting the transmitting-side coil and the transmitting-side resonant capacitor in series and connecting them to the inverter circuit. The receiving-side resonant circuit is formed by connecting the receiving-side coil and at least one receiving-side resonant capacitor. The resonant frequencies of the transmitting-side resonant circuit and the receiving-side resonant circuit are set to be consistent.

[0022] [Effects of the invention]

[0023] According to the wireless power supply system of the present invention, since it is wireless power supply using parity-time symmetry (hereinafter referred to as "PT symmetry"), there is no need to adjust the position and angle of the power transmission side coil and the power receiving side coil for power supply to the artificial device installed inside the human body. Even if the position of the power transmission side coil and the power receiving side coil is slightly deviated, the power supply will not be interrupted and high transmission efficiency can be maintained, so that power can be supplied wirelessly at all times. In addition, by using physical phenomena such as PT symmetry for power control, the structure of external devices and internal devices becomes simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram showing a conventional method of supplying power to an auxiliary artificial heart by wired power supply.

[0025] Figure 2 This is a schematic diagram showing a method of attaching an external device of a conventional wireless power supply system for supplying power to an artificial heart based on an electromagnetic induction method or a magnetic field resonance method to a human body.

[0026] Figure 3 This is a schematic diagram showing a method of attaching an external device to a human body in the wireless power supply system for supplying power to an auxiliary artificial heart (artificial device) using PT symmetry according to the first embodiment of the present invention.

[0027] Figure 4 This is an explanatory diagram showing a schematic configuration of an internal device for driving an external device and an auxiliary artificial heart in a wireless power supply system for supplying power to an auxiliary artificial heart (artificial device) using PT symmetry according to Embodiment 1 of the present invention.

[0028] Figure 5 This is a conceptual diagram showing a circuit of a wireless power supply system for supplying power to an auxiliary artificial heart (artificial device) using PT symmetry according to the first embodiment of the present invention.

[0029] Figure 6 This is an explanatory diagram showing a schematic configuration of a power transmission-side coil and a power reception-side coil used in the wireless power feeding system utilizing PT symmetry according to the first embodiment of the present invention.

[0030] Figure 7 This is a graph showing the relationship between the positional relationship of two coils (a power transmission side coil and a power reception side coil) used in the wireless power feeding system using PT symmetry according to the first embodiment of the present invention and the magnetic coupling coefficient. DETAILED DESCRIPTION

[0031] The present invention relates to a wireless power supply system for supplying power to artificial devices such as an artificial heart installed inside a human body.

[0032] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0033] Figure 1 This is a schematic diagram showing a conventional method of supplying power to an auxiliary artificial heart by wire. The auxiliary artificial heart is a structure in which a pump driven by a motor is attached below the actual heart to assist blood circulation. Figure 1 , a state is shown in which a cable 2 such as an electric wire is connected to an auxiliary artificial heart 1 (indicated by a solid line) installed inside a human body, the cable 2 is led out of the human body from a hole 3 opened in the abdomen of the human body, and is connected to an external control device 4, and the control device 4 is connected to an external power source (a power source outside the human body) 5. Here, regarding the cable 2 such as the electric wire, the portion inside the human body is indicated by a dotted line, and the portion outside the human body is indicated by a solid line, and the state in which the cable 2 is led out of the human body from the hole 3 opened in the abdomen is clearly visible.

[0034] And, currently, Figure 1 As shown, an auxiliary artificial heart 1 is installed under the patient's heart and is operated by a motor to assist blood circulation. However, in this case, as the power for driving the electric pump, a hole 3 is usually opened in the abdomen (human body) and a cable 2 such as an electric wire is led out of the body, and an external power source 5 is connected to the outside of the body or a control device (a control device for controlling the drive of the electric pump) 4 is connected to the outside of the body to operate the auxiliary artificial heart 1.

[0035] However, since a hole 3 is opened in the abdomen (human body) for the insertion of cables 2 such as electric wires, there are various problems such as the patient being unable to take a bath or the risk of infection being increased. Therefore, it is hoped that a wireless power supply technology that allows electric power to flow (supply power) in a non-contact (wireless) manner is applied to the auxiliary artificial heart 1 installed inside the human body.

[0036] In addition, if the patient is an adult, he or she can take care of the hole 3 for the wires and cables 2 to pass through for the auxiliary artificial heart 1 installed inside the human body, and can move carefully. However, in the case of a child patient, special attention must be paid to the care of the hole 3, and the risk of infection is also increased. Therefore, it is more desirable to apply wireless power supply technology to the auxiliary artificial heart 1 that allows electricity to flow (supply power) non-contactly without opening a hole 3 in the abdomen (human body).

[0037] On the other hand, there are many known wireless power supply technologies, such as electromagnetic induction technology and magnetic field resonance technology. Among them, electromagnetic induction wireless power supply technology is a technology used in charging mobile phones, etc., where the coils are arranged up and down, that is, the same principle as a transformer, and power can only be transmitted when the distance between the power transmission side coil and the power receiving side coil (transmission distance) is very short.

[0038] However, since the transmission distance of electromagnetic induction wireless power supply technology is relatively short at about several millimeters, it is impossible to increase the distance between the power transmitting side coil and the power receiving side coil. Moreover, even if the positions of the power transmitting side coil and the power receiving side coil are slightly deviated or separated, charging and power supply cannot be performed. In other words, it is relatively fragile to position deviation, so there is a problem that it is difficult to apply to artificial devices installed inside the human body, such as artificial heart 1.

[0039] In addition, since the transmission distance of the wireless power supply technology of the magnetic field resonance method is relatively long, at about several centimeters to several meters, it is possible to increase the distance between the power transmission side coil and the power receiving side coil compared to the electromagnetic induction method. Therefore, it has reached a level close to practical application. However, there is a sensitivity problem. If the distance between the power transmission side coil and the power receiving side coil is not fixed to a constant, the power cannot be transmitted. Whether it is closer or farther than this distance, or just slightly off at an angle, the transmission efficiency will also decrease, and the required power cannot be transmitted. In other words, this method is also relatively fragile to position deviation, so there is a problem that it is difficult to apply to artificial devices installed inside the human body, such as auxiliary artificial hearts 1.

[0040] Therefore, under the current situation, as a wireless power supply system for supplying power to an auxiliary artificial heart based on magnetic field resonance, such as Figure 2 In that way, the control device 4 is firmly fixed by means of shoulder straps 51, diagonal straps 52, etc., and the control device 4 as an external device is connected to or has an external power source 5 built in. Even if the patient moves, the distance and angle between the power transmitting side coil of the control device 4 outside the human body and the power receiving side coil (not shown) near the auxiliary artificial heart inside the human body remain constant (do not deviate). Otherwise, it cannot be used. Figure 2 This is a schematic diagram showing a method of attaching external equipment (such as the control device 4 ) of a conventional wireless power supply system for supplying power to an auxiliary artificial heart based on an electromagnetic induction method or a magnetic field resonance method to a human body.

[0041] However, if Figure 2As shown, even in a system in which the distance and angle between the power transmission side coil and the power reception side coil are kept constant by firmly fixing the control device 4 outside the human body to the human body using a shoulder strap 51, a diagonal strap 52, etc., there is a situation where the position deviates by several centimeters up and down due to the movement of the human body. In addition, there is a problem that it is easy to get prickly heat under the belt in summer. It is also difficult to replace the battery for supplying power to the external device when it is exhausted. The system can only be used under considerable constraints, which is inconvenient to use.

[0042] In addition, Patent Document 2 discloses a wireless power supply system, which includes a control device in a wireless power supply technology of a magnetic field resonance method, and has a function of adjusting the positional relationship and angle of a power transmission side coil and a power reception side coil, so as to supply stable power to an auxiliary artificial heart, etc. Thus, even if the position deviates by several centimeters up and down due to the movement of the human body, the control device can change the parameters to adjust the position each time.

[0043] However, in this case, since it is necessary to have a function of adjusting the distance between the power transmission side coil and the power reception side coil to be constant or adjusting the angle to be constant, the external control device (external device such as the power transmission side device) becomes large, and it is necessary to constantly perform high-level control such as adjusting the positional relationship and angle between the coils, which causes a burden on the control unit of the external control device (external device such as the power transmission side device). In addition, when the battery supplying power to the external device is replaced, there is also a problem that the high-level control function stops.

[0044] Therefore, there is an urgent need for a wireless power supply system that does not require adjustment and control of the position and angle of the power transmitting side coil and the power receiving side coil installed in the human body, and can wirelessly supply power without interruption even if the position and angle of the power transmitting side coil and the power receiving side coil are slightly deviated. Various wireless power supply methods have been repeatedly experimented and verified, but the current situation is that no method that can withstand practical application has been found.

[0045] Here, as one of the wireless power supply methods, there is a wireless power supply technology that utilizes Parity-Time symmetry (hereinafter referred to as "PT symmetry"). In this wireless power supply system that utilizes PT symmetry, even if the transmission distance changes, even if the transmission side coil and the receiving side coil are out of position, as long as the PT symmetry can be maintained, the transmitted power will always remain constant. That is, the wireless power supply system that utilizes PT symmetry replaces the AC power supply in the previous wireless power supply technology of the magnetic field resonance method with an inverter that behaves electrically the same as a negative resistor, that is, a structure of an inverter that behaves as a negative resistor.

[0046] This is a known technology disclosed in, for example, Patent Document 3. However, if described in a little more detail, the inverter that exhibits negative resistance is an inverter whose switching frequency and voltage amplitude are not fixed in advance, and whose switching frequency in the circuit structure is determined based on the apparent resonant frequency of the wireless power supply circuit observed from the output end of the inverter. It is an inverter that follows the change of the apparent resonant frequency of the wireless power supply circuit with a fast response speed of the switching frequency, wherein the change of the apparent resonant frequency of the wireless power supply circuit is caused by the change of the transmission distance of the coil, the position deviation, etc. Here, the wireless power supply circuit includes the power transmission side resonant circuit and the power receiving side resonant circuit, and all subsequent circuits connected thereto. Moreover, the apparent resonant frequency is the actual resonant frequency that takes into account the interaction between the power transmission side resonant circuit and the power receiving side resonant circuit.

[0047] However, the previous wireless power supply system using PT symmetry is driven at a high frequency of about 1 to 3 MHz, so an air-core coil is used as the power transmission side coil and the power receiving side coil, so the size of the coil needs to be increased, and there is also a disadvantage that the applicable applications are limited. Specifically, the size of the coil in the previous wireless power supply system using PT symmetry is a coil with a diameter of about 60 cm (see non-patent document 1). Moreover, due to the high frequency, if a metal object (conductive object) is placed around the power transmission side coil and the power receiving side coil, there is also a disadvantage that the transmission efficiency is reduced due to the eddy current loss generated in the conductive object. Therefore, this technology cannot be applied to artificial devices such as auxiliary artificial hearts installed inside the human body.

[0048] In order to solve the problems in the previous wireless power supply system using PT symmetry, one of the applicants of the present invention invented a wireless power supply device using PT symmetry. Since it uses a low frequency below 100kHz, the transmission efficiency is less reduced even if metal objects are placed around it. Even if the transmission distance changes or the position of the coil deviates, the high transmission efficiency can be maintained continuously. In addition, the transmission side coil and the receiving side coil can be miniaturized, and can be used in various applications. The applicant filed a patent application for the invention in 2021 (see patent document 3).

[0049] Furthermore, the present invention is the result of repeated experiments and trial and error in order to apply the technology in the wireless power supply device utilizing PT symmetry of the prior application Patent Document 3 to a wireless power supply system for powering artificial devices installed inside the human body, such as auxiliary artificial hearts.

[0050] Implementation method 1.

[0051] The wireless power supply system for supplying power to an auxiliary artificial heart using PT symmetry in the first embodiment of the present invention comprises: an internal device provided inside the human body for driving an artificial device provided inside the human body; and an external device provided outside the human body, which supplies power to the internal device contactlessly from the external device by non-contact magnetic coupling. Moreover, since the wireless power supply utilizes PT symmetry, there is no need to make a hole in the human body, and it is not necessary to connect from outside the body through wires, but it is possible to transmit power to the artificial device installed inside the human body wirelessly, thus having the excellent effect of eliminating the risk of infection for the patient. It should be noted that in this first embodiment, an auxiliary artificial heart is described as the artificial device.

[0052] Figure 3 1 is a schematic diagram showing a method of attaching an external device to a human body in a wireless power supply system for supplying power to an auxiliary artificial heart (artificial device) using PT symmetry according to Embodiment 1 of the present invention. Here, the external device 19 (see Figure 4 ) of the external device group 10. Figure 4 This is an explanatory diagram showing the schematic configuration of an external device 19 and an internal device 29 for driving an auxiliary artificial heart (artificial heart control circuit 26 and artificial heart 27) in a wireless power supply system for supplying power to an auxiliary artificial heart (artificial device) using PT symmetry according to Embodiment 1 of the present invention. Figure 5 This is a conceptual diagram showing a circuit of a wireless power supply system for supplying power to an auxiliary artificial heart (artificial device) using PT symmetry according to the first embodiment of the present invention.

[0053] Figure 3 In the figure, the internal device group 20 provided inside the human body is schematically indicated by a single-dot chain line (refer to Figure 4 ), showing a state where the external device group 10 set outside the human body is attached to the waist of the human body (patient) through a waist belt 53 in order to supply power to the internal device group 20 without contact. Figure 3 As shown, in the first embodiment of the present invention, it is not necessary to Figure 2 The control device 4 outside the human body is securely fixed to the human body by means of shoulder straps 51, diagonal straps 52, etc., as in the previous method of installing the external equipment (control device 4, etc.) in the wireless power supply system for auxiliary artificial heart based on magnetic field resonance into the human body, and the external equipment group 10 can be installed on a belt 53 such as a normal trouser belt.

[0054] in addition, Figure 4 The overall schematic structure of the wireless power supply system for supplying power to an auxiliary artificial heart (artificial device) using PT symmetry according to the first embodiment of the present invention is shown. Figure 4As shown, the wireless power supply system of this embodiment 1 is composed of an external device group 10 including an external device 19 provided outside the human body and an internal device group 20 including an internal device 29 provided inside the human body. The external device 19 is provided with an inverter circuit 13, a power transmission side resonance circuit 12, and a power transmission side coil 11, and here, the external device group 10 is configured to include an external power source 5.

[0055] The external power source 5 supplies power to the inverter circuit 13, and any power source that outputs a DC voltage may be used, specifically, a battery, or a device such as an AC adapter that converts a commercial power source (100V, 50Hz or 60Hz) from a socket into a DC voltage. It should be noted that here, the external power source 5 is described as a battery built into the external device group 10, but it may also be a case where a battery connected to the external device 19 is carried on the back, or a commercial power source from a socket is used, and it is not limited to being set inside the external device group 10.

[0056] The inverter circuit 13 is a device for converting the DC voltage supplied from the external power supply 5 into an AC voltage, and is an inverter that behaves electrically the same as a negative resistor. The inverter that behaves as a negative resistor has been described above, so a detailed description is omitted here. Figure 5 As will be described later, when the DC voltage is converted into an AC voltage in the inverter circuit 13 and then transmitted to the power transmission side coil 11, the power transmission side resonant circuit 12 is required. That is, the inverter circuit 13 is made so that the relationship between the output current and the output voltage of the inverter circuit 13 is the same as the relationship between the current and the voltage of the negative resistor, and an oscillation phenomenon occurs when the power transmission side resonant circuit 12 is connected to the inverter circuit 13. It should be noted that the oscillation phenomenon is a well-known technology, so a detailed description is omitted here.

[0057] In this way, the power (DC voltage) from the external power supply 5 built into the external device group 10 is converted into AC voltage by the inverter circuit 13 in the external device 19, and the AC voltage is converted into an AC magnetic field via the power transmitting side resonant circuit 12 and the power transmitting side coil 11, thereby transmitting the power to the receiving side coil 21 in a contactless manner.

[0058] As described above, the external device 19 provided outside the human body is connected to the external power source 5 and includes at least the inverter circuit 13, the power transmission side resonance circuit 12 and the power transmission side coil 11. The inverter circuit 13 converts the DC voltage supplied from the external power source 5 into an AC voltage, and the power transmission side resonance circuit 12 and the power transmission side coil 11 convert the AC voltage converted by the inverter circuit 13 into an AC magnetic field and transmit power to the internal device 29. The external device group 10 having the external device 19 and the external power source 5 built in is small and lightweight. Figure 3As shown, it can be attached to a belt 53 such as a normal trouser belt.

[0059] In addition, the internal device group 20 including the auxiliary artificial heart (artificial heart control circuit 26 and artificial heart 27) is set inside the human body and directly installed in the human heart. Figure 4 As shown, the internal device 29 is provided with a power receiving side coil 21, a power receiving side resonance circuit 22, a rectifier circuit 23, a DC / DC converter 24, and a battery 25. These internal devices 29 are connected to an auxiliary artificial heart composed of an artificial heart control circuit 26 and an artificial heart 27, and supply the power transmitted from the external device 19 to the auxiliary artificial heart.

[0060] It should be noted that the auxiliary artificial heart is a well-known device, so a detailed description of the auxiliary artificial heart (artificial heart control circuit 26 and artificial heart 27) is omitted here. The artificial heart 27 has a fluid delivery pump inside for circulating blood, and the artificial heart control circuit 26 is a control circuit for controlling the flow rate of the fluid delivery pump.

[0061] The power receiving side coil 21 and the power receiving side resonant circuit 22 will also be referred to. Figure 5 As will be described later, similarly to the need for the power transmitting side coil 11 and the power transmitting side resonant circuit 12 in the external device 19 on the power transmitting side, the internal device 29 provided inside the human body also needs to be connected with the power receiving side resonant circuit 22 and the power receiving side coil 21 constituting a set.

[0062] When the power (AC magnetic field) from the external device 19 is transmitted from the power transmission side coil 11 to the power receiving side coil 21 in a non-contact manner, the power receiving side coil 21 and the power receiving side resonant circuit 22 interlink the AC magnetic field generated from the power transmission side coil 11, and the power (AC voltage) output by the power receiving side coil 21 and the power receiving side resonant circuit 22 is converted into a DC voltage by the rectifier circuit 23. At this time, when using this power, in order to drive a pump or a motor at a predetermined voltage such as 24V or 12V, it is preferably adjusted to the predetermined voltage.

[0063] Therefore, the DC / DC converter 24 adjusts the DC power (DC voltage) converted in the rectifier circuit 23 to a target specified voltage value. In addition, the value of the voltage received by the DC / DC converter 24 also changes to a certain extent due to changes in the transmission distance, etc. The change in voltage has an adverse effect on the rotation speed of the pump and the motor, so it is necessary to adopt a certain method to suppress the change in the voltage value. The DC / DC converter 24 also has the function of suppressing the change in the voltage value and supplies a stable voltage to the pump and the motor. It should be noted that as long as it is a general DC / DC converter, it has the above-mentioned function, so the DC / DC converter 24 can be any general DC / DC converter.

[0064] In addition, the internal device 29 of the first embodiment includes a storage battery 25, converts the AC voltage received from the external device 19 into a DC voltage, adjusts it to a predetermined voltage by the DC / DC converter 24, and temporarily stores (saves) the power stabilized to the predetermined voltage value in the storage battery 25. This is because, as in the first embodiment, when the artificial device is an auxiliary artificial heart (artificial heart control circuit 26 and artificial heart 27), even if the power supply is interrupted for a moment due to some accidents, emergencies, or during the replacement of the battery for supplying power to the external device 19 on the power transmission side, the heart may stop and cause death, so it is conceivable to build in a small storage battery that can operate for, for example, 5 minutes or 10 minutes to prepare for the occurrence of some of the above-mentioned inconveniences.

[0065] That is, the battery 25 is a necessary structure when the wireless power supply system is applied to an artificial heart, and depending on the artificial device used, the battery may not be provided. It should be noted that, when the internal device 29 does not have the battery 25, the auxiliary artificial heart (artificial heart control circuit 26 and artificial heart 27) can be driven by the power of the voltage value output by the DC / DC converter 24.

[0066] In addition, as described above, in order to adjust the DC voltage converted by the rectifier circuit 23 to a predetermined voltage value and output it stably, it is preferable to have a DC / DC converter 24, but the DC / DC converter 24 is not an essential structure, so when the internal device 29 does not have a DC / DC converter 24, the battery 25 only needs to temporarily store the DC power converted by the rectifier circuit 23. It should be noted that when the internal device 29 does not have a DC / DC converter 24 or a battery 25, it is only necessary to drive the auxiliary artificial heart (artificial heart control circuit 26 and artificial heart 27) by the DC power converted by the rectifier circuit 23.

[0067] In this way, the internal device 29 is provided with at least the receiving-side coil 21 and the receiving-side resonant circuit 22 for interlinking the AC magnetic field generated by the transmitting-side coil 11, and the rectifier circuit 23 for converting the AC voltage output from the receiving-side coil 21 and the receiving-side resonant circuit 22 into a DC voltage, and the auxiliary artificial heart (artificial heart control circuit 26 and artificial heart 27) is driven by the DC power converted by the rectifier circuit 23. Furthermore, the internal device 29 is provided with a storage battery 25 for temporarily storing the DC power converted by the rectifier circuit 23, and the auxiliary artificial heart (artificial heart control circuit 26 and artificial heart 27) is driven by the power stored in the storage battery 25.

[0068] In this way, the power (DC voltage) from the external power source 5 built into the external device group 10 is converted into AC voltage by the inverter circuit 13 in the external device 19, and the AC voltage is converted into AC magnetic field via the power transmission side resonance circuit 12 and the power transmission side coil 11, and the power is transmitted to the power receiving side coil 21 in a non-contact manner, thereby supplying power to the auxiliary artificial heart (artificial heart control circuit 26 and artificial heart 27), and the auxiliary artificial heart drives a pump that assists the blood circulation of the actual heart. Here, the setting position of the power receiving side coil 21 set inside the human body can be any state as long as it can be connected to other devices in the internal device 29 when set, but there is a surplus space near the heart and the auxiliary artificial heart set inside the human body, so it is more natural to set it near the navel near the internal device group 20.

[0069] and, Figure 4 The circuit diagram shown in FIG. 1 is composed of the power transmission side coil 11, the power transmission side resonant circuit 12 and the inverter circuit 13. Figure 5 The left half of the circuit diagram is composed of the receiving side coil 21, the receiving side resonant circuit 22 and the rectifier circuit 23. Figure 5 The right half of . That is, Figure 5 The left half of is a circuit diagram of the external device 19 (a circuit diagram of the power transmitting-side resonant circuit 12 ), and the right half is a circuit diagram of the internal device 29 (a circuit diagram of the power receiving-side resonant circuit 22 ).

[0070] like Figure 5 As shown, the power transmission side resonant circuit 12 is formed by connecting the power transmission side coil 11 and the power transmission side resonant capacitor C1 in series and connecting them to the inverter circuit 13, and the power reception side coil 21 is connected to at least one power reception side resonant capacitor (C2 or C 21 or C 22 ) are connected to form a receiving-side resonance circuit 22, and the resonance frequency of the transmitting-side resonance circuit 12 is set to be consistent with the resonance frequency of the receiving-side resonance circuit 22, that is, it is crucial to set the resonance frequencies of the two resonance circuits on the transmitting side and the receiving side to be consistent.

[0071] Here, as the power receiving side resonance circuit 22, in addition to the following Figure 5 In addition to the circuit shown in (a) of the embodiment in which a receiving-side resonant capacitor C2 is connected in parallel to the receiving-side coil 21, a circuit in which Figure 5 As shown in (b), a receiving-side resonant capacitor C is connected in series with the receiving-side coil 21. 21 And connect another receiving side resonant capacitor C in parallel 22 That is, in the Figure 5 (a) Figure 5 In the case of (b), the receiving coil 21 is connected to at least one receiving resonant capacitor (C2 or C 22 ) are connected in parallel to form a power receiving side resonance circuit 22. Also, as another mode, Figure 5 As shown in (c), a circuit mode in which one receiving-side resonant capacitor C2 is connected in series to the receiving-side coil 21 may be considered. That is, the receiving-side resonant circuit 22 is formed by connecting the receiving-side coil 21 to at least one receiving-side resonant capacitor.

[0072] It should be noted that, in the first embodiment of the present invention, Figure 5 A configuration in which one receiving-side resonance capacitor C2 is connected in parallel to the receiving-side coil 21 as in the mode (a) will be described.

[0073] Through such a circuit, an alternating magnetic field is generated from an external device 19 disposed outside the human body toward an internal device 29 disposed inside the human body. However, if exposed to a high-frequency alternating magnetic field, cells and tissues will generate heat and be damaged, so there is a restriction that high frequencies cannot be used when wirelessly powering artificial devices installed inside the human body. In addition, as mentioned above, the wireless power supply system using PT symmetry previously studied is a structure that is implemented at a high frequency of 1 to 3 MHz, so it is difficult to apply this technology to a wireless power supply system that powers artificial devices installed inside the human body, such as an artificial heart.

[0074] In addition, the energy loss in a conductive object in an AC magnetic field is proportional to the square of the frequency, that is, if the frequency increases 10 times, the heat generation increases 100 times, and if the frequency increases 100 times, the heat generation increases by 10,000 times, so it is very important to keep the frequency low. Therefore, the applicant of this application aims to reduce the heat generation by more than 100 times by making the frequency below 200kHz, which is about one-tenth of the frequency of the previous wireless power supply system using PT symmetry. Currently, experiments are being conducted at a frequency of about 50kHz.

[0075] Furthermore, in a previously studied wireless power supply system utilizing PT symmetry, the transmission-side coil and the receiving-side coil are structures that can be realized using air-core coils of about 60 cm in diameter. However, coils of this size are almost impossible to install inside the human body. Therefore, not only is the frequency high, but also the shape and size of the coils make it impossible to apply this existing technology to wireless power supply systems for powering artificial devices installed inside the human body, such as artificial hearts.

[0076] Figure 6 1 is an explanatory diagram showing a schematic configuration of a power transmission side coil 11 and a power reception side coil 21 used in a wireless power supply system utilizing PT symmetry according to Embodiment 1 of the present invention. Figure 6 As shown in (a), the power transmission side coil 11 and the power receiving side coil 21 are both solenoid-type coils in which windings (such as Li Ci wire) 111 and 211 are wound around magnetic cores 100 and 200 using soft magnetic materials such as ferrite materials. It should be noted that the shape of the coil used for wireless power supply mostly uses a spiral coil (or pancake-shaped coil) that is vortex-shaped and circular. The fact that the coil is a solenoid coil is also one of the characteristics of the present invention. In addition, by using such a solenoid-type coil with a soft magnetic material as the magnetic core, it can be a small-sized coil, so it can be set inside the human body.

[0077] In addition, if Figure 6 As shown in (b), the magnetic core 100 (or 200) has two ends thereof, that is, except for the portion where the winding 111 (or 211) is wound ( Figure 6 The two ends of the coil 101 and the coil 201 and the coil 202 are substantially rectangular parallelepiped-shaped and have no winding (unwound) windings. The two ends of the coil 101 and the coil 201 and the coil 202 are substantially rectangular parallelepiped-shaped and have no windings ... Figure 6 The area of ​​the two end portions of the upper figure (inner side) of (b) is larger than the area of ​​the other surfaces of the magnetic pole. This has the effect of increasing the magnetic coupling coefficient when the power transmission side coil 11 and the power reception side coil 21 face each other, making it possible to extend the transmission distance of the coil and expand the allowable range of the position deviation of the coil.

[0078] Here, the magnetic coupling coefficient between two coils is explained. When the positions of the two coils change, for example, the distance between the two coils changes or the angle changes, the magnetic coupling coefficient k between the two coils changes. m Change. The magnetic coupling coefficient k between the two coils m It decreases when the transmission distance between the two coils becomes longer, and also decreases when the position deviation of the coils becomes larger. Conversely, when the distance between the two coils is shortened, the magnetic coupling coefficient k mWhen the magnetic coupling coefficient k is close to 1, it increases. m The value is 0~1.

[0079] Figure 7 is a graph showing the relationship between the positional relationship of two coils (the power transmission side coil 11 and the power reception side coil 21 ) used in the wireless power supply system using PT symmetry according to the first embodiment of the present invention and the magnetic coupling coefficient. Figure 7 (a) shows the relationship between the transmission distance between the two coils and the magnetic coupling coefficient. Figure 7 (b) shows the relationship between the positional deviation in the left-right direction between the two coils and the magnetic coupling coefficient.

[0080] Figure 7 The ○ marks in the graph represent experimental measurement results, and the solid line and the dashed line represent theoretically calculated values. However, the experimental results and the calculated values ​​are roughly the same. Figure 7 As can be seen from (a), the shorter the transmission distance between the two coils, the larger the magnetic coupling coefficient, and the longer the transmission distance, the smaller the magnetic coupling coefficient. Figure 7 (b) shows that when the two coils face each other and there is no deviation to the left or right (position deviation of 0 mm), the magnetic coupling coefficient is the largest. Whether it is the case of deviation to the left or the case of deviation to the right, the larger the position deviation, the smaller the magnetic coupling coefficient. It should be noted that only the case of deviation to the left or right is shown here, but it can be seen that the case of deviation along the longitudinal direction and the case of deviation in the rotation direction (orientation) are the same. The larger the deviation, the larger the magnetic coupling coefficient.

[0081] Furthermore, when the magnetic coupling coefficient is less than a certain value, the PT symmetry cannot be maintained. That is, there is a limit (critical) magnetic coupling coefficient that can maintain the PT symmetry. However, by reducing the value of this limit, i.e., the critical magnetic coupling coefficient k mC , even if the transmission distance between the coils changes or the position of the coils deviates, the output power can be stabilized. That is, the smaller the critical magnetic coupling coefficient, the more the PT symmetry can be maintained even if the distance between the two coils changes or the position or angle deviates, and the constant output power can be always supplied.

[0082] The critical magnetic coupling coefficient k represents the limit value (critical value) of the magnetic coupling coefficient. mC It can be expressed as formula (1).

[0083] [Formula 1]

[0084]

[0085] Here, the denominator of the first term, Q2, is a value indicating the quality factor (Q value) of the power receiving coil 21, the denominator of the second term, ω0, is the resonance frequency, C2 is the power receiving resonant capacitance of the power receiving coil 21, and R L is the load resistance of the wireless power supply system, that is, in this example, it represents the equivalent resistance value of the artificial heart including the DC / DC converter. Moreover, the above formula (1) is the addition operation of the first term and the second term, so as long as the first term and the second term can be made into smaller values, the value of the formula (1) added together can also be made into a smaller value. That is, for the first term, since it is desired to reduce 1 / Q2, it can be known that Q2 preferably has a larger value.

[0086] In addition, when the self-inductance of the power receiving side coil 21 is set to L2, the resonant frequency ω0 can be expressed as formula (2), so it is transformed into formula (3), and by further transformation C2, it can be expressed as formula (4). It should be noted that the power receiving side resonant circuit 22 is as follows Figure 5 As in (b), a receiving-side resonant capacitor C is connected in series with the receiving-side coil 21. 21 , and connected in parallel with another power receiving side resonant capacitor C 22 In the case of the circuit of the mode, C2=C 21 ･C 22 / (C 21 +C 22 ) is established, and in this case, it can also be expressed as formula (4). And, when formula (4) is substituted into C2 of formula (1), the critical magnetic coupling coefficient k mC It can be expressed as formula (5). And the formula which shows only the result of formula (5) is formula (6).

[0087] [Formula 2]

[0088]

[0089] [Formula 3]

[0090]

[0091] [Formula 4]

[0092]

[0093] [Formula 5]

[0094]

[0095] [Formula 6]

[0096]

[0097] Thus, the critical magnetic coupling coefficient k is expressed as mC The above formula (6) derived by transforming the formula (1) is also an addition operation of the first term and the second term. Therefore, as long as the first term and the second term are both small values, the value of the added formula (6) can also be small. And, as mentioned above, with respect to the first term, it is desired to reduce 1 / Q2, so it can be known that the value representing the quality factor of the receiving side coil 21, that is, Q2, is preferably a larger value. And, with respect to the second term, it can be known that the self-inductance L2 of the receiving side coil 21 is preferably small, the resonant frequency ω0 is also preferably small, and the load resistance R of the wireless power supply system is preferably small. L Preferably larger.

[0098] This determines the guidelines, so, for example, if the critical magnetic coupling coefficient k is to be mC To suppress it to less than 0.1, at least the first term of formula (6), 1 / Q2, must be less than 0.1, so the value Q2 representing the quality factor of the receiving-side coil 21 must be set to a value greater than 10. In this regard, in practice, the first term is set to less than 0.01 by setting Q2 to 100 or more. In addition, the self-inductance L2 of the receiving-side coil 21 is set to less than 200μH (microhenry), the resonant frequency ω0 is set to less than 200kHz, and the load resistance R L becomes 100 Ω or more, and at least the second term of formula (6) becomes 0.2 or less.

[0099] For example, if the critical magnetic coupling coefficient k of formula (6) is mC is 0.2, then based on Figure 7 As can be seen from the curve graph, if the transmission distance between the two coils is within about 5 cm and the position deviation is within about 4 cm (± about 4 cm) on the left and right, the PT symmetry can be maintained, and a constant output power can be always supplied from the external device 19 on the power transmitting side to the device on the power receiving side, i.e., the internal device 29.

[0100] In addition, for example, if the critical magnetic coupling coefficient k of formula (6) is mC is 0.3, then based on Figure 7 As can be seen from the curve graph, if the transmission distance between the two coils is within about 3 cm and the position deviation is within about 2 cm (± about 2 cm) on the left and right, the PT symmetry can be maintained, and a constant output power can be always supplied from the external device 19 on the power transmitting side to the device on the power receiving side, i.e., the internal device 29.

[0101] As described above, by making the first term in formula (6) less than 0.01 and the second term less than 0.2, the critical magnetic coupling coefficient k calculated by formula (6) is mCThe parameters (resonance frequency ω0, quality factor Q2 of the power receiving coil 21, self-inductance L2 of the power receiving coil 21, load resistance R L ), so that the transmission distance between the two coils is within about 5 cm, and with respect to the position deviation, it is within about 4 cm (± about 4 cm) on the left and right. Even if the distance between the two coils changes or the positions deviate, the PT symmetry can be maintained, and a constant output power can be always supplied from the external device 19 on the power transmitting side to the device on the power receiving side, that is, the internal device 29. Therefore, stable power can be supplied from the external device 19 disposed outside the human body to the internal device 29 disposed inside the human body.

[0102] Therefore, the wireless power supply system using PT symmetry according to the first embodiment of the present invention is a system that can be fully applied to artificial devices such as an artificial heart installed inside a human body.

[0103] Furthermore, if the parameters can be further set so that the critical magnetic coupling coefficient k of formula (6) mC If it becomes, for example, less than 0.05, the distance between the two coils is within about 10 cm, and regarding the position deviation, when it is about 7 cm (± about 7 cm) to the left and right, even if the distance between the two coils changes or the position deviates, the PT symmetry can be maintained, and a constant output power can be always supplied from the external device 19 on the power transmitting side to the device on the power receiving side, that is, the internal device 29. Therefore, the restrictions on human movements and the restrictions on the installation positions of the external device 19 and the internal device 29 are further alleviated, resulting in an easy-to-use wireless power supply system.

[0104] It should be noted that according to experiments, in order to maintain the PT symmetry of the first embodiment of the present invention, the Q value Q2 of the power receiving coil 21 needs to be increased, preferably at least greater than the Q value Q1 of the power transmitting coil 11 .

[0105] Furthermore, as described above, if the self-inductance L2 of the power receiving coil 21 is not reduced, PT symmetry cannot be maintained over a long distance, so the self-inductance L2 of the power receiving coil 21 needs to be small, preferably suppressed to 50 μH or less.

[0106] Thus, by using the critical magnetic coupling coefficient k mC By setting parameters (quality factor Q value, inductance, resonance frequency, load resistance, etc.) to the smallest possible values, PT symmetry can be maintained even when the distance between the power transmitting side coil 11 and the power receiving side coil 21 changes or the positions are displaced, and a constant output power can always be supplied to the device on the power receiving side, i.e., the internal equipment 29.

[0107] As described above, in the wireless power supply system using PT symmetry according to the first embodiment of the present invention, the power transmission side resonance circuit 12 is formed by connecting the power transmission side resonance capacitor C1 in series to the power transmission side coil 11, and the power receiving side resonance circuit 22 is formed by connecting the power receiving side resonance capacitor C2 to the power receiving side coil 21. Furthermore, the resonance frequencies ω0 of the two resonance circuits on the power transmission side and the power receiving side are set to be consistent. Furthermore, within the assumed distance (transmission distance) between the power transmission side coil 11 and the power receiving side coil 21, the parameters (quality factor Q value, inductance, resonance frequency, load resistance, etc.) are set so that the wireless power supply system of the present invention maintains PT symmetry, that is, so that the value of the above formula (6) is as small as possible.

[0108] Furthermore, since the strength of the interaction between the power transmission side coil 11 and the power reception side coil 21 is very important, in order to maintain a strong mutual influence relationship, it is preferred that the respective coils have the same shape and size, or the power transmission side coil 11 is larger than the power reception side coil 21. Figure 6 As shown in (a), coils of the same size are used.

[0109] In addition, it is repeated that the shape of the coil is preferably a solenoid type as mentioned above. As the shape of the coil, there are solenoid type and spiral type. No matter which shape it is, the PT symmetry can be maintained. Usually, a spiral coil is used, but the wireless power supply system of the present invention is a transcutaneous power transmission that supplies power to an artificial device set inside the human body without contact, so high frequencies cannot be used. Therefore, a lower frequency is used, but at low frequencies, there is a tendency for the Q value of the solenoid type coil to become higher than that of the spiral type. If the Q value of the coil becomes higher, the PT symmetry can be maintained over a long distance, so it can be said that a solenoid-shaped coil is better.

[0110] In addition, according to the wireless power supply system utilizing PT symmetry of embodiment 1 of the present invention, in order to enable uninterrupted power supply even if the distance and angle between the power transmitting side coil 11 and the power receiving side coil 21 change, the distance between the power receiving side coil 21 provided in the internal device group 20 in which the auxiliary artificial heart (artificial heart control circuit 26 and artificial heart 27) is provided and the power transmitting side coil 11 provided in the external device group 10 is preferably within 10 cm.

[0111] As mentioned above, as the maximum transmission distance between coils that can maintain PT symmetry, there is a tendency that the larger the size of the coil, the longer the transmission distance. Figure 4 and Figure 6 The area of ​​the surface where the coils face each other is called the coil surface. For example, the area of ​​the coil surface is (5cm×3cm=15cm 2), although it is also affected by the above parameter settings, if the critical magnetic coupling coefficient k of formula (6) is mC If the parameter setting is set to 0.2 or less, it is expected that the maximum transmission distance between the coils will be about 5 cm. Therefore, in this case, the distance between the power transmission side coil 11 and the power receiving side coil 21 is preferably within 5 cm. That is, the external device 19 needs to be arranged within 5 cm from the power receiving side coil 21 (internal device 29) so that the distance between the power receiving side coil 21 set inside the human body and the power transmission side coil 11 set in the external device 19 is within 5 cm.

[0112] Furthermore, if the distance between the external device group 10 and the power receiving side coil 21 is within 5 cm, that is, if the distance between the power transmitting side coil 11 and the power receiving side coil 21 is within 5 cm, even if the distance changes, power can always be supplied from the power transmitting side coil 11 to the power receiving side coil 21, and the power supply from the external device group 10 to the auxiliary artificial heart (artificial heart control circuit 26 and artificial heart 27) in the internal device group 20 will not be interrupted, and power can always be supplied to the auxiliary artificial heart wirelessly.

[0113] Therefore, specifically, if an auxiliary artificial heart (artificial heart control circuit 26 and artificial heart 27) is arranged below the actual heart to assist blood circulation by a pump driven by a motor, the power receiving side coil 21 is arranged just below the navel of the human body by arranging the power receiving side coil 21 in the internal device group 20 in which the auxiliary artificial heart is arranged, and a belt 53 like a normal trouser belt is wrapped around the waist of the human body, and the external device group 10 is installed near the buckle part of the belt 53. Then, the power transmitting side coil 11 provided inside the external device group 10 will be arranged within 5 cm from the power receiving side coil 21 inside the human body, and power can be always supplied from the power transmitting side coil 11 to the power receiving side coil 21, and power supply from the external device group 10 to the auxiliary artificial heart (artificial heart control circuit 26 and artificial heart 27) in the internal device group 20 will not be interrupted, so that power is always supplied to the auxiliary artificial heart wirelessly.

[0114] In addition, by using such a structure, i.e., utilizing a physical phenomenon such as PT symmetry for power control, there is also an advantage that the structure of external devices such as an external power transmission side device and internal devices becomes simple, and the patient can easily replace the battery for supplying power to the external device. The battery replacement operation needs to be performed regularly, but in the case of the previous wireless power supply system, the power supply is temporarily stopped due to the position deviation during battery replacement, so it is difficult for the patient to perform it alone, and even if there is help from others, it is necessary to be very careful, and if the user is not accustomed to it, it is impossible to perform a smooth replacement operation.

[0115] However, in the case of the wireless power supply system according to the first embodiment of the present invention, even if there is a slight positional deviation, power can be always supplied to the power receiving side coil 21 without any problem, so for example Figure 3 As indicated by the dotted line, the battery replacement operation of the entire external device group 10 can be completed by simply winding the belt 53' that fixes the external device group 10 with a new battery (external power source 5) under the belt 53 that fixes the current external device group 10, and then untying the original belt 53. Therefore, the patient can easily replace the battery by himself.

[0116] In addition, if the battery is replaced in this way, the waist belt 53 (or 53') can be fixed at a position slightly offset from the previous position, so there is no need to worry about it even in the summer and other seasons when the belt position is prone to heat rash, and when the battery is exhausted, a new belt can be set at a different position and then replaced simply by untying the previous belt, so the patient can easily perform the replacement operation by himself. In addition, it is also possible to bathe only the part below the belt or wipe the body by slightly moving the belt, so it is also very effective in terms of hygiene.

[0117] Furthermore, when the waist belt 53 (or 53') is wound slightly loosely, it is considered that the belt may turn around and the distance between the external device group 10 provided with the power transmission side coil 11 and the auxiliary artificial heart (artificial heart control circuit 26 and artificial heart 27) in the internal device group 20 may be increased. Therefore, it is possible to pre-install a plurality of power transmission side coils 11 inside the external device group 10 in consideration of the position deviation in the rotation direction of the belt. In this case, there are a plurality of power transmission side coils 11 and a single power receiving side coil 21, but it is sufficient to add a function that can automatically select the power transmission side coil 11 paired with the power receiving side coil 21 (a function that selects the power transmission side coil 11 at the shortest distance from the power receiving side coil 21 for power supply).

[0118] It should be noted that when there are multiple power transmitting coils 11 and only one power receiving coil 21, the resonant circuits of the unused coils among the power transmitting coils 11 are usually turned off, but power may be transmitted from multiple power transmitting coils 11 to one power receiving coil 21.

[0119] On the contrary, assuming that there is one power transmission side coil 11 and a plurality of power reception side coils 21, in this case, the frequency cannot be automatically adjusted, and it is difficult to maintain PT symmetry, so such a configuration cannot be adopted.

[0120] It should be noted that, in this embodiment 1, as a device for wirelessly supplying power to an internal device that drives an artificial device installed inside the human body, a structure for supplying power to an auxiliary artificial heart is described as an example, but the wireless power supply system is not limited to artificial hearts (auxiliary artificial hearts) but can also be applied to other artificial devices such as artificial kidneys, artificial pancreases, artificial inner ears, artificial eyes, etc.

[0121] Specifically, an artificial kidney is a structure that filters blood, and requires power (electricity) to drive the pump that transports blood. In addition, an artificial pancreas is a structure that detects the glucose concentration in the blood and sprays the required amount of insulin into the blood, and requires power (electricity) to drive the sensor and the insulin spray pump. In addition, an artificial inner ear is a structure that uses a microphone to convert sound into electricity, and after amplification and information processing, it transmits electrical stimulation to the nerves, and the drive of its circuit requires power (electricity). In addition, an artificial eye is a structure that converts image information into electrical signals using a semiconductor camera element, and after information processing, it transmits electrical stimulation to the nerves, and the drive of its circuit requires power (electricity).

[0122] In this way, in the case of artificial devices other than artificial hearts and auxiliary artificial hearts, similar to artificial hearts, the driving of the pump requires power, and current is used to transmit signals to nerves, so a power source (electricity) is required for the driving part, but it is preferred that a method of wirelessly transmitting power from outside the body without opening a hole in the human body and connecting via wires is used. Therefore, the wireless power supply system using PT symmetry of embodiment 1 of the present invention is also applicable to these artificial devices, so that there is no need to worry about position deviation and angle deviation, and the convenience of the artificial device can be improved.

[0123] As described above, according to the wireless power supply system of embodiment 1 of the present invention, since it is wireless power supply using PT symmetry, there is no need to make a hole in the human body, and the internal device that drives the artificial device installed inside the human body can transmit power wirelessly without being connected from the outside through wires, so the risk of infection to the patient disappears. In addition, there is no need to adjust the position and angle of the power transmission side coil and the power receiving side coil for power supply to the internal device installed inside the human body. Even if the position of the power transmission side coil and the power receiving side coil is slightly deviated, the power supply will not be interrupted, and high transmission efficiency can be maintained, so that power can always be supplied wirelessly. In addition, since physical phenomena such as PT symmetry are used for power control, the structure of the external device and the internal device becomes simple.

[0124] It should be noted that the present invention may modify any constituent elements of the embodiments or omit any constituent elements of the embodiments within the scope of the invention.

[0125] Industrial Applicability

[0126] The wireless power supply system of the present invention can be applied to various artificial devices installed inside the human body, such as artificial kidneys, artificial pancreases, artificial inner ears, and artificial eyes, in addition to artificial hearts (auxiliary artificial hearts).

[0127] Description of Reference Numerals

[0128] 1 Previous artificial hearts

[0129] 2 Wires and cables

[0130] 3 Holes in the human body (abdomen)

[0131] 4 Control devices outside the human body

[0132] 5 External power source (power source outside the human body)

[0133] 10 External Device Group

[0134] 11 Transmission side coil

[0135] 12 Transmission side resonance circuit

[0136] 13 Inverter circuit

[0137] 19 External Devices

[0138] 20 Internal Equipment Group

[0139] 21 Receiving coil

[0140] 22 Resonant circuit on the receiving side

[0141] 23 Rectification circuit

[0142] 24 DC / DC Converter

[0143] 25. Battery

[0144] 26 Artificial heart control circuit (artificial device control circuit)

[0145] 27 Artificial heart (artificial device)

[0146] 29 Internal Equipment

[0147] 51 Shoulder Straps

[0148] 52 Diagonal belt

[0149] 53, 53' belt

[0150] 100, 200 core

[0151] 101, 102, 201, 202 magnetic poles

Claims

1. A wireless power supply system, characterized in that: The invention utilizes the Parity-Time symmetry and comprises: an internal device arranged inside the human body, which drives an artificial device arranged inside the human body; and an external device arranged outside the human body, which supplies power to the internal device from the external device in a contactless manner. The external device is provided with: an inverter circuit connected to an external power source and converting a DC voltage supplied from the external power source into an AC voltage; and a power transmission side resonance circuit and a power transmission side coil, which convert the AC voltage converted by the inverter circuit into an AC magnetic field and transmit power to the internal device. The internal device is provided with: a power receiving side coil and a power receiving side resonant circuit, which interlink the AC magnetic field generated by the power transmitting side coil; and a rectifier circuit, which converts the AC voltage output from the power receiving side coil and the power receiving side resonant circuit into a DC voltage, and the internal device drives the artificial device using the DC power converted by the rectifier circuit. The power transmission side resonant circuit is formed by connecting the power transmission side coil and the power transmission side resonant capacitor in series and connecting them to the inverter circuit. The power receiving side resonant circuit is formed by connecting the power receiving side coil to at least one power receiving side resonant capacitor, The resonant frequencies of the power transmission side resonant circuit and the power reception side resonant circuit are set to coincide with each other.

2. The wireless power supply system according to claim 1, characterized in that: When the resonance frequency is ω0, the quality factor of the power receiving coil is Q2, the self-inductance of the power receiving coil is L2, and the load resistance of the wireless power supply system is R L hour, The critical magnetic coupling coefficient k is a critical value of the magnetic coupling coefficient between the power transmission coil and the power reception coil expressed by the following formula 1: mC The resonant frequency ω0, the quality factor Q2 of the power receiving coil, the self-inductance L2 of the power receiving coil, and the load resistance R of the wireless power supply system are set so as to be 0.2 or less. L , [Formula 1] 。 3. The wireless power supply system according to claim 1 or 2, characterized in that: The power transmission coil and the power reception coil are both solenoid-shaped coils in which a winding is wound around a core made of a soft magnetic material. The magnetic core has substantially rectangular parallelepiped magnetic poles at both ends thereof, around which the winding is not wound. The magnetic pole is formed so that an area of ​​a surface facing each other when the power transmission-side coil and the power reception-side coil face each other is larger than an area of ​​another surface of the magnetic pole.

4. The wireless power supply system according to claim 1 or 2, characterized in that: The internal device is further provided with a storage battery for temporarily storing the DC power converted by the rectifier circuit, and the artificial device is driven by the power stored in the storage battery.

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