In-vivo device wireless power transmission system and method based on magnetic reconstruction technology

Abstract

The invention discloses an in-vivo equipment wireless power transmission system and method based on a magnetic reconstruction technology, the system comprises a transmitting end and a receiving end, the transmitting end comprises a first conductor ring, a second conductor ring and four conductor supporting legs, the first conductor ring is of an athletic track type structure, and the second conductor ring is of a magnetic reconstruction structure; first conductor rings are arranged on the upper side and the lower side of the transmitting end in parallel in a mirror image distribution mode respectively, the two ends of the two sides between the adjacent first conductor rings are connected through conductor supporting feet respectively, and intersection points of the four conductor supporting feet and the first conductor ring on one side are arranged in a square shape; a second conductor ring is arranged on the outer side of the first conductor ring in parallel, the first conductor ring is used for exciting and generating a uniform magnetic field in the X and Y directions, and the second conductor ring is used for exciting and generating a uniform magnetic field in the Z direction so as to cooperatively generate an omni-directional, uniform and equiamplitude-distributed magnetic field. According to the invention, the receiving end in any direction and position in the trunk can maintain a high mutual inductance coefficient with the transmitting end, so that the power can be stably and efficiently transmitted from the transmitting end to the receiving end, and the method has good practicability.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless power transmission of implantable devices in human body, and specifically relates to a wireless power transmission system and method for implantable devices in human body based on magnetic reconstruction technology. Background Art

[0002] At present, implantable medical devices (IMDs) have attracted widespread attention due to their advantages such as intelligence, miniaturization, and adjustable action. At present, IMDs have been used clinically for blood pressure regulation, urination, hormone delivery, tissue regeneration, etc. Although IMDs have brought great benefits to patients, their development is greatly limited by the power supply capacity. This is because the capacity of the widely used lithium batteries is limited, and patients have to replace them regularly through surgery, which brings a triple burden of physical, mental and economic burden to patients. In addition, although the traditional percutaneous wiring power supply method can ensure a stable power supply, the risk of percutaneous infection is high, and the patient experience is poor. In order to overcome the above problems, people have proposed to use wireless power transfer (WPT) technology as an IMDs power solution. In contrast, WPT technology can achieve wireless charging in vitro, thereby effectively avoiding surgery and infection problems.

[0003] Although the existing IMDs based on WPT technology have made great progress, when designing the transmitter, the existing WPT system often only considers whether it meets the IMDs' requirements for WPT system power transmission stability, transmission power size, and system safety, and ignores the user experience. The transmitters of various special-shaped structures (such as spherical, rectangular, etc.) are placed directly on the human torso, which seriously restricts the user's normal life and also brings great psychological burden to the user. In addition, the existing wireless power transmission systems usually have clear requirements for the location and orientation of the implanted device. This greatly limits the scope of clinical application of implantable devices. Summary of the invention

[0004] The purpose of the present invention is to provide a wireless power transmission system and method for in-vivo devices based on magnetic reconstruction technology, aiming to solve the above-mentioned problems, optimize the structure of the transmitting end, and enable the receiving end to be placed at any angle during power transmission. Based on the Biot-Savart law, the present invention realizes the reconstruction of the magnetic field by optimizing the design of the current distribution position, size and phase, and excites a uniform, equal-amplitude magnetic field distribution based on Cartesian coordinates in all directions (X, Y and Z axes) inside the transmitting end (human body trunk). This design enables the receiving end and the transmitting end in any direction and position in the trunk to maintain a high mutual inductance coefficient, so that power can be stably and efficiently transmitted from the transmitting end to the receiving end.

[0005] The present invention is mainly achieved through the following technical solutions:

[0006] A wireless power transmission system for in-vivo devices based on magnetic reconstruction technology includes a transmitting end and a receiving end, wherein the transmitting end includes a first conductor ring, a second conductor ring and four conductor legs, wherein the first conductor ring is an athletic track type structure, and the upper and lower sides of the transmitting end are respectively provided with first conductor rings in parallel and mirror distribution, and the two ends on both sides between adjacent first conductor rings are respectively connected by conductor legs, and the intersections of the four conductor legs and the first conductor ring on one side are arranged in a square; a second conductor ring is arranged in parallel on the outer side of the first conductor ring, the first conductor is used to excite and generate a uniform magnetic field in the X and Y directions, and the second conductor ring is used to excite and generate a uniform magnetic field in the Z direction, thereby collaboratively generating an omnidirectional uniform and equally distributed magnetic field, so that the receiving end can be placed at any angle in the space surrounded by the first conductor ring and the conductor legs for power transmission.

[0007] The transmitting end of the existing wireless power transmission system usually ignores the user experience. It is generally designed as a sphere or a cuboid and directly installed on the human torso, which will seriously affect the user's normal life and even bring great psychological burden to him. The present invention proposes a first conductor ring in the shape of an athletic track that is conformal to the human waist, which solves the above-mentioned defects and effectively improves the comfort of use.

[0008] In order to better implement the present invention, further, a compensating reactance is provided on the first conductor loop between adjacent conductor legs, so that the equivalent inductance of the first conductor loop between any adjacent conductor legs is the same.

[0009] In order to better implement the present invention, further, the first conductor ring includes two straight tracks parallel to each other, and two ends of adjacent straight tracks are respectively provided with curved tracks, and the intersection between the curved track and the straight track is connected to the conductor leg.

[0010] In order to better implement the present invention, further, the second conductor ring has the same structure and size as the first conductor ring, and the first conductor ring and the second conductor ring are arranged in a mirror image distribution.

[0011] In order to better implement the present invention, further, a feeding point is respectively provided on the four conductor legs and the second conductor ring. Preferably, the first conductor ring and the second conductor ring are respectively made of non-magnetic metal conductor materials.

[0012] In order to better implement the present invention, further, the receiving end includes a coaxially arranged I-type magnetic core and a spiral coil, and the spiral coil is arranged on the outer side of the middle part of the I-type magnetic core.

[0013] The present invention is mainly achieved through the following technical solutions:

[0014] A method for wireless power transmission of an in-vivo device based on magnetic reconstruction technology is implemented using the above-mentioned wireless power transmission system, and includes the following steps:

[0015] Step S1: placing the receiving end in the space surrounded by the first conductor ring and the conductor legs;

[0016] Step S2: Start the power source to provide a single-frequency electrical signal; excite an omnidirectional, uniform, and equally distributed magnetic field in the space surrounded by the first conductor ring and the conductor legs; the magnetic flux passes through the receiving coil at the receiving end to achieve wireless power transmission.

[0017] In order to better implement the present invention, further, in the step S2, when the equivalent inductance between any adjacent conductor legs is equal, the circuit formed by the first conductor ring and the conductor legs forms a closed loop with a periodic LC structure; in the resonant state, the calculation formula of the resonant frequency ω is as follows:

[0018]

[0019] Where: C1 is the equivalent capacitance of the conductor leg;

[0020] L1 is the equivalent inductance between adjacent conductor legs;

[0021] A current proportional to sinθ is generated in the conductor leg, thereby exciting a uniform XY magnetic field in the transmitting end; where: θ = (n-1)*(2π / N), and n = 1, 2, ..., N; where N is the number of periodic units, and N = 4.

[0022] In order to better implement the present invention, further, in step S2, the closed loop of the periodic LC structure causes the single-frequency electrical signal to produce a phase change of Δj(ω) in each period unit, and at this time, the following is satisfied:

[0023] NΔφ(ω)=2π (1)

[0024] Where: N is the number of periodic units, and N = 4;

[0025] Δφ(ω) is the phase change caused by the periodic unit.

[0026] In order to better implement the present invention, further, in the step S2, four electrical signals with equal amplitudes and phases differing by 90° are fed into the four conductor legs in a counterclockwise or clockwise direction respectively; and currents with the same frequency, amplitude and phase are fed into the upper and lower second conductor loops respectively.

[0027] The beneficial effects of the present invention are as follows:

[0028] (1) The present invention realizes non-contact energy transmission. The transceiver uses magnetic field reconstruction to generate an omnidirectional uniform magnetic field inside the coil through deformation and compensation of the transmitting coil and design of the receiving coil, thereby effectively improving the power transmission efficiency and transmission stability of the receiving coil. The present invention can place the receiving end inside the human body at any angle on the basis of ensuring high and stable transmission efficiency, and turn on the power source, so as to realize efficient and stable wireless power transmission, which has good practicality.

[0029] (2) The present invention is based on the Biot-Savart law and realizes the reconstruction of the magnetic field of the transmitting end by optimizing the design of the current amplitude and phase, and generates an omnidirectional (X, Y and Z three-axis) uniform and equal-amplitude distributed magnetic field based on Cartesian coordinates in the human body torso inside the transmitting end. The present invention enables the receiving end in any direction and position in the torso to maintain a high mutual inductance coefficient with the transmitting end, so that power can be stably and efficiently transmitted from the transmitting end to the receiving end, and has good practicality.

[0030] (3) The present invention particularly meets the new requirements of future implantable medical devices for high stability, high power and high transmission efficiency of wireless power transmission systems. The transmitter of the present invention can stably and efficiently transmit power to implantable medical devices in any orientation and position in the human body. For example, in the future, implantable medical devices can maintain real-time, stable and efficient power transmission during movement in the body, which has good practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the structure of the transmitting end and the receiving end of the in-vivo device wireless power transmission system based on the magnetic reconstruction technology of the present invention;

[0032] Figure 2 is a schematic diagram of the connection structure between the first conductor ring and the conductor leg and a schematic diagram of the magnetic field excitation thereof;

[0033] Figure 3 is an equivalent circuit of the first conductor loop and the conductor leg;

[0034] Figure 4Magnetic induction intensity in the X and Y directions inside the transmitter;

[0035] Figure 5 is a schematic diagram of the structure of the second conductor ring and a schematic diagram of its magnetic field excitation;

[0036] Figure 6 is a schematic diagram of the magnetic field distribution in the vertical direction calculated by the finite element algorithm;

[0037] Figure 7 It is a schematic diagram of the connection structure between the magnetic core and the spiral coil;

[0038] Figure 8 Schematic diagram of the transmission efficiency of the receiving end in the human torso.

[0039] Among them: 1-first conductor loop, 2-conductor leg, 3-second conductor loop, 4-receiving end, 5-helical coil, 6-I-type magnetic core, 7-feeding point. DETAILED DESCRIPTION

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. It should be understood that the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, and therefore should not be regarded as limiting the scope of protection. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technical personnel in this field without making creative work are within the scope of protection of the present invention.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] Embodiment 1:

[0043] A wireless power transmission system for an in-vivo device based on magnetic reconstruction technology includes a power source, a transmitter and a receiver 4, such as Figure 1 As shown, the transmitting end includes two first conductor rings 1, two second conductor rings 3 and four conductor legs 2, the first conductor ring 1 is a track-type structure, and the second conductor ring 3 has the same structure as the first conductor ring 1. The power source refers to a source for emitting electromagnetic waves, and preferably, the power source generally includes an external signal source and a power amplifier.

[0044] The two first conductor rings 1 are arranged in parallel and mirror-image distribution, and the two ends of the two sides between adjacent first conductor rings 1 are connected by conductor legs 2 respectively, and the intersections of the four conductor legs 2 and the first conductor rings 1 are arranged in a square. A second conductor ring 3 is arranged in parallel on the outside of the first conductor ring 1, and the adjacent first conductor rings 1 and second conductor rings 3 are not cross-linked with each other. Feeding points 7 are respectively arranged on the conductor legs 2 and the second conductor ring 3. The first conductor is used to excite and generate a uniform magnetic field in the X and Y directions, and the second conductor ring 3 is used to excite and generate a uniform magnetic field in the Z direction, so as to collaboratively generate an omnidirectional uniform and equal-amplitude distributed magnetic field, so that the receiving end 4 can be placed at any angle in the space surrounded by the first conductor ring 1 and the conductor legs 2 for wireless power transmission.

[0045] Preferably, the junction of the straight line and the curved line of the first conductor loop 1 is connected to the conductor leg 2 , and the four vertices of the junction of the straight line and the curved line of the first conductor loop 1 form a square.

[0046] Preferably, a compensating reactance is provided on the first conductor loop 1 between adjacent conductor legs 2, so that the equivalent inductance of the conductor loops between any adjacent conductor legs 2 is the same. Here, the compensating reactance can be compensated on a straight track or a curved track by connecting a series or parallel reactance (inductance or capacitance).

[0047] like Figure 2 As shown, (a) is a schematic diagram of the connection structure between the first conductor ring 1 and the conductor support leg 2, and (b) is a schematic diagram of the magnetic field excitation of the first conductor ring 1. Figure 3 for Figure 2 (a) is an equivalent circuit diagram, wherein Vs represents a fixed frequency power source that can provide a single frequency electrical signal. C1 represents the equivalent capacitance value of the conductor leg 2. L1 and L2 represent the equivalent inductance of the straight track and the curved track of the first conductor loop 1, respectively.

[0048] Preferably, the present invention first proposes to introduce a compensating reactance at a straight line or a curved line of the first conductor loop 1, so as to ensure that the equivalent inductance L1 is equal to L2. Figure 4 As shown in the figure, (a) is the magnetic field amplitude distribution of the magnetic induction intensity in the X direction of the transmitting end obtained by finite element algorithm calculation; (b) is the magnetic field amplitude distribution of the magnetic induction intensity in the Y direction of the transmitting end obtained by finite element algorithm calculation. The uniformity of the magnetic field in the horizontal direction in the study area is generally good, and the closer to the center position, the higher the uniformity.

[0049] like Figure 5 As shown in the figure, (a) is a schematic diagram of the structure of the second conductor ring 3; (b) is a schematic diagram of its magnetic field excitation in the vertical direction (Z direction). Based on this principle, the magnetic field in the vertical direction (Z direction) in the transmitting end is excited by the two second conductor rings 3 distributed in a mirror image outside the transmitting end. Figure 6As shown, it can be seen that the magnetic field uniformity in the Z direction is good.

[0050] Preferably, the receiving end 4 is composed of a coaxial I-shaped magnetic core 6 and a spiral coil 5. The receiving end 4 can be placed at any angle inside the space surrounded by the inner conductor ring and the conductor support.

[0051] At present, magnetic cores are widely used in the receiving end 4 of wireless power transmission systems. The magnetic core can effectively disturb the magnetic field around the receiving coil. Therefore, by effectively designing the magnetic core and coil structure, the quality factor of the receiving coil can be effectively improved, thereby improving the transmission efficiency of the system.

[0052] like Figure 7 As shown, (a) is a schematic diagram of the connection structure with an I-type magnetic core 6 and a spiral coil 5, and (b) is a schematic diagram of the connection structure with a traditional cylindrical magnetic core and a spiral coil 5. The I-type magnetic core 6 increases the space occupied by the magnetic core material at both ends of the coil. This design can better focus the magnetic field around the coil and effectively improve the quality factor of the receiving coil. The simulation results show that the maximum increase in the quality factor is close to 40%. According to the coupling mode principle, increasing the quality factor can put the system in a strong coupling region k TR / Γ T Γ R >1, where k TR represents the coupling coefficient between the transmitting end and the receiving end 4; Γ represents the attenuation coefficient; T and R represent the transmitting end and the receiving end 4 respectively, thereby improving the transmission efficiency of the system.

[0053]

[0054] Where: η is the transmission efficiency of the system;

[0055] Γ W is the attenuation factor of the load.

[0056] like Figure 8 As shown, (a) is a schematic diagram of the transmission efficiency of the receiving end 4 with an I-type magnetic core 6 in the human body; (b) is a schematic diagram of the transmission efficiency of the receiving end 4 with a traditional cylindrical magnetic core in the human body. When using the same transmitting end, it can be seen that the I-type magnetic core 6 effectively improves the transmission efficiency of the system, and its space share of transmission efficiency exceeding 2% reaches 66.7%, compared with only 50% for the cylindrical magnetic core structure. In addition, the receiving end 4 of the I-type magnetic core 6 does not increase the overall length and width of the receiving end 4 on the basis of effectively improving the transmission efficiency and stability, thereby meeting the implantable device's demand for a small size of the receiving end 4.

[0057] The present invention is based on magnetic reconstruction technology, and by controlling the magnitude and phase of the current on the conductor structure of the transmitting end, an omnidirectional (X, Y and Z three axes) uniform and equal-amplitude magnetic field distribution based on Cartesian coordinates is excited at the human body torso inside the transmitting end. The present invention can maintain a high mutual inductance coefficient between the receiving end 4 and the transmitting end in any direction and position in the torso, thereby enabling power to be stably and efficiently transmitted from the transmitting end to the receiving end 4, and has good practicality.

[0058] Embodiment 2:

[0059] A method for wireless power transmission of an in-vivo device based on magnetic reconstruction technology is implemented using the above-mentioned wireless power transmission system, and includes the following steps:

[0060] Step S1: placing the receiving end 4 in the space surrounded by the first conductor ring 1 and the conductor leg 2;

[0061] Step S2: Start the power source to provide a single-frequency electrical signal; the transmitting end excites an omnidirectional, uniform, and equally distributed magnetic field in the space surrounded by the first conductor ring 1 and the conductor leg 2, and the magnetic flux passes through the receiving coil of the receiving end 4 to achieve wireless power transmission.

[0062] like Figure 3 As shown, when L1 is equal to L2, the entire circuit forms a closed loop with a periodic LC structure. Each period unit causes the signal to produce a phase change of Δj(ω). In order to improve the transmission efficiency of the system, it is necessary to keep the system in a resonant state, that is, to satisfy:

[0063] NΔφ(ω)=2π (1)

[0064] Where N (=4) is the number of periodic units. In the resonant state, the relationship between the resonant frequency and the leg capacitance and equivalent inductance satisfies:

[0065]

[0066] At this time, if Figure 2 As shown, a current proportional to sinθ is generated in the conductor leg 2, thereby exciting a uniform transverse magnetic field in the transmitting end, where [θ = (n-1)*(2π / N), and n = 1, 2, ..., N]; where N = 4. The synthetic magnetic field excites a state similar to "circular polarization" in the transmitting end.

[0067] Secondly, according to the requirements of formulas (1) and (2), the present invention feeds four electrical signals with equal amplitudes and phases that differ by 90° into the four conductor legs 2 in a counterclockwise or clockwise direction. Figure 5As shown, two currents with the same frequency, amplitude and phase are fed into the two second conductor loops 3. The conduction current excites a magnetic field with good uniformity and in the Z (vertical) direction inside the conductor loop.

[0068] The present invention can realize the placement of the receiving end 4 at any angle inside the human body on the basis of ensuring high and stable transmission efficiency, and turn on the power source to realize efficient wireless power transmission. The transmitting end of the present invention can perform stable and efficient power transmission to implantable medical devices in any orientation and position in the human body. The present invention especially meets the new requirements of future implantable medical devices for high stability and high transmission efficiency of wireless power transmission systems. For example: In the future, implantable medical devices can maintain real-time, stable and efficient power transmission during movement in the body, and have good practicality.

[0069] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A wireless power transmission system for in-vivo devices based on magnetic reconstruction technology, characterized in that: The invention comprises a transmitting end and a receiving end (4), wherein the transmitting end comprises a first conductor ring (1), a second conductor ring (3) and four conductor legs (2), wherein the first conductor ring (1) is a track-type structure, wherein the first conductor ring (1) is arranged on the upper and lower sides of the transmitting end in parallel and mirror-image distribution, wherein the two ends on both sides between adjacent first conductor rings (1) are connected by conductor legs (2), and the intersections of the four conductor legs (2) and the first conductor ring (1) on one side are arranged in a square; and a second conductor ring (3) is arranged in parallel on the outer side of the first conductor ring (1), wherein the first conductor is used to excite and generate a uniform magnetic field in the X and Y directions, and the second conductor ring (3) is used to excite and generate a uniform magnetic field in the Z direction, thereby synergistically generating an omnidirectional uniform magnetic field with equal amplitude distribution.

2. According to claim 1, a wireless power transmission system for in-vivo devices based on magnetic reconstruction technology is characterized in that: A compensating reactance is provided on the first conductor loop (1) between adjacent conductor legs (2) so that the equivalent inductance of the first conductor loop (1) between any adjacent conductor legs (2) is the same.

3. According to claim 1, a wireless power transmission system for in-vivo devices based on magnetic reconstruction technology is characterized in that: The first conductor ring (1) comprises two mutually parallel straight tracks, and two ends of adjacent straight tracks are respectively provided with curved tracks, and the intersection between the curved track and the straight track is connected to the conductor support foot (2).

4. The in-vivo device wireless power transmission system based on magnetic reconstruction technology according to any one of claims 1 to 3, characterized in that: The second conductor ring (3) has the same structure and size as the first conductor ring (1), and the first conductor ring (1) and the second conductor ring (3) are arranged in a mirror-image distribution.

5. According to claim 1, a wireless power transmission system for in-vivo devices based on magnetic reconstruction technology is characterized in that: The receiving end (4) comprises a coaxially arranged I-type magnetic core (6) and a spiral coil (5), and a spiral coil (5) coaxial with the magnetic core is arranged outside the middle of the I-type magnetic core (6).

6. A method for wireless power transmission of an in-vivo device based on magnetic reconstruction technology, using the wireless power transmission system according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step S1: placing the receiving end (4) in the space surrounded by the first conductor ring (1) and the conductor support leg (2); Step S2: starting the power source to provide a single-frequency electrical signal; exciting an omnidirectional, uniform, and equally distributed magnetic field in the space surrounded by the first conductor ring (1) and the conductor support leg (2); and the magnetic flux passes through the receiving coil of the receiving end (4), thereby realizing wireless power transmission.

7. The method for wireless power transmission of an in-vivo device based on magnetic reconstruction technology according to claim 6, characterized in that: In the step S2, when the equivalent inductances between any adjacent conductor legs (2) are equal, the circuit formed by the first conductor ring (1) and the conductor legs (2) forms a closed loop with a periodic LC structure; in the resonant state, the calculation formula of the resonant frequency ω is as follows: Where: C1 is the equivalent capacitance of the conductor leg (2); L1 is the equivalent inductance between adjacent conductor legs (2); A current proportional to sinθ is generated in the conductor leg (2), thereby exciting uniform magnetic fields in the X and Y directions in the transmitting end; wherein: θ=(n-1)*(2π / N), and n=1, 2, ..., N; wherein N is the number of periodic units, and N=4.

8. The method for wireless power transmission of an in-vivo device based on magnetic reconstruction technology according to claim 7, characterized in that: In step S2, the closed loop of the periodic LC structure causes the single-frequency electrical signal to produce a phase change of Δj(ω) in each period unit, and at this time, the following is satisfied: NΔφ(@)=2π (1) Where: N is the number of periodic units, and N = 4; Δφ(ω) is the phase change caused by the periodic unit.

9. A method for wireless power transmission of an in-vivo device based on magnetic reconstruction technology according to any one of claims 6 to 8, characterized in that: In step S2, four electrical signals with equal amplitudes and phases that differ by 90° are fed into the four conductor legs (2) in a counterclockwise or clockwise direction; and currents with the same frequency, amplitude and phase are fed into the upper and lower second conductor loops (3).

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