Implantable cardiac pacemaker array type multi-excitation IPT wireless energy supply system and mutual inductance analysis model and transmission efficiency and output power analysis model of implantable cardiac pacemaker array type multi-excitation IPT wireless energy supply system

Abstract

The invention relates to the technical field of cardiac pacemakers, and particularly discloses an implantable cardiac pacemaker array type multi-excitation IPT wireless energy supply system and a mutual inductance analysis model and a transmission efficiency and output power analysis model thereof. According to the mutual inductance analysis model disclosed by the invention, an output power analysis model and a transmission efficiency analysis model of the IPT system are further constructed by analyzing the mutual inductance condition between the coils. According to the invention, the model enables the electric energy to be effectively transmitted in a relatively long distance and a complex human tissue environment, achieves the flexible control of the energy transmission, can adjust the working state of the transmitting coil according to the demands of the pacemaker, improves the transmission efficiency of the electric energy, and improves the reliability of the pacemaker. And the service life of the system is prolonged. Meanwhile, the technology also enhances the adjustable degree of the coupling coefficient, and optimizes the coupling effect by adjusting the coil parameters, thereby improving the energy transmission efficiency, and guaranteeing the stable operation of the cardiac pacemaker.

Description

Technical Field

[0001] This invention belongs to the field of cardiac pacemaker technology, and particularly relates to an array-type multi-excitation IPT wireless power supply system for implantable cardiac pacemakers, as well as its mutual inductance analysis model and transmission efficiency and output power analysis model. Background Technology

[0002] In the field of modern medicine, implantable pacemakers are a key means of treating arrhythmias, and their power supply mainly relies on built-in batteries. However, considering that the lifespan of batteries is limited, usually between 5 and 10 years, patients must undergo surgery to replace the batteries after they are depleted. This process not only brings physical pain and economic pressure to patients, but may also increase the risk of surgery-related complications, such as infection and bleeding. The limitations of this method are mainly reflected in the following aspects: (1) Limited lifespan: The battery lifespan of traditional non-rechargeable pacemakers is usually between 5 and 10 years. This time range is affected by various factors such as pacemaker model, frequency of use, and individual patient differences. Once the battery is depleted, the pacemaker cannot work properly, and patients need to replace it through surgery. This not only increases the patient's pain and economic burden, but also increases the surgical risk; (2) Surgical replacement requirements: Replacing the pacemaker battery requires local anesthesia, and the old battery is removed through a small incision before the new battery is implanted. Although the surgical risk is relatively low, the surgical risk is still not negligible for elderly patients or those in poor physical condition; (3) The battery is too large in size and weight: Traditional non-rechargeable batteries occupy a large volume and weight in pacemakers, which may add extra burden to patients who are small or weak, thus affecting their comfort and quality of life.

[0003] The application of wireless power transfer technology in cardiac pacemakers has significant advantages, including avoiding the risks of battery replacement surgery, improving patients' quality of life, adapting to changes in human physiology, enhancing the potential for intelligent and miniaturized devices, and helping to reduce medical waste and environmental pollution. However, the application of single-coil wireless power transfer technology in cardiac pacemakers faces several challenges: (1) Limitations in transmission distance: The efficiency of single-coil wireless power transfer decreases significantly with increasing transmission distance. Due to the attenuation effect of human tissue on electromagnetic signals, when the transmission distance exceeds a certain range, such as in obese patients or patients with deep implantation sites, insufficient power transmission may occur, failing to meet the needs of normal pacemaker operation. Typically, the effective transmission distance of a single-coil wireless power transfer system is relatively short, generally within a few centimeters, which poses a challenge for its application in the human body; (2) The problem of low coupling coefficient: In practical applications, the coupling coefficient of a single-coil wireless power transfer system is relatively low. The dielectric constant and other properties of human tissue affect the electromagnetic coupling between coils, leading to a decrease in energy transmission efficiency. In addition, cardiac pacemakers require a stable energy supply during charging, and a low coupling coefficient may cause fluctuations in energy supply, affecting the charging performance of the pacemaker. For example, changes in the patient's body posture or slight electromagnetic changes in the surrounding environment may affect the coupling coefficient, thus making the energy received by the pacemaker unstable; (3) High requirements for coil position accuracy: Single-coil wireless power transmission requires precise alignment of the relative positions of the transmitting coil and the receiving coil. During the charging process of the cardiac pacemaker, human movement and daily activities may cause the coil position to shift. If the transmitting coil and the receiving coil are not properly aligned, it will seriously affect the energy transmission efficiency. For example, when the patient bends over or turns, the receiving coil in the implanted cardiac pacemaker may be misaligned with the transmitting coil outside the body, resulting in interruption of power transmission or a significant decrease in efficiency; (4) Safety risks: Although single-coil wireless power transmission reduces the number of electromagnetic interference sources, electromagnetic safety risks still exist. Long-term exposure of the human body to a certain intensity of electromagnetic field may produce adverse effects such as thermal effects. For cardiac pacemakers, excessively high electromagnetic field strength may interfere with the electronic components of the pacemaker and even cause potential thermal damage to the surrounding heart tissue. In addition, if the wireless power transmission system malfunctions, such as a sudden increase in transmission power, it may cause serious harm to the patient's health. Summary of the Invention

[0004] This invention provides an array-type multi-excitation IPT wireless power supply system for implantable cardiac pacemakers, along with its mutual inductance analysis model and transmission efficiency and output power analysis model. The main purpose is to address the current problems of weak stability in charging power and transmission efficiency of cardiac pacemakers.

[0005] To solve one or more of the above problems, the present invention adopts the following technical solution:

[0006] The first aspect of this invention relates to a mutual inductance analysis model for an implantable cardiac pacemaker array-type multi-excitation IPT system (implantable cardiac pacemaker array-type multi-excitation electromagnetic induction non-contact energy transmission system). This analysis model has many forms of representation. It can be an analysis system, such as an analysis system based on a computing platform, or a functional module of an analysis system. Any application of this solution in an implantable cardiac pacemaker array-type multi-excitation IPT should be considered within the scope of this invention.

[0007] An array-type multi-excitation IPT system has a receiving coil placed inside the body to power the pacemaker, and a transmitting coil group located outside the body consisting of several coplanar arrayed transmitting coils. Its equivalent circuit is as follows: Figure 2 As shown, both the receiving coil and the transmitting coil are square with a side length of L. The distance between any two adjacent transmitting coils in the transmitting coil group is d, and -L≤d≤L. The overlap distance d between two adjacent transmitting coils is negative.

[0008] In specific applications, the structure of either the transmitting coil or the receiving coil can adopt the coil design of a conventional IPT system or other modified coils that can perform electromagnetic induction and can be used in this system.

[0009] For ease of explanation, this paper assumes that all transmitting coils are located in the XOY plane of the coordinate system (a virtual plane, used as a reference, the same below), and the coordinates of the four vertices of the transmitting coil in the i-th row and j-th column are respectively

[0010] The mutual inductance analysis model is mainly used to analyze and obtain the mutual inductance between the transmitting coil and the receiving coil in row i and column j of this implantable cardiac pacemaker array-type multi-excitation IPT system. This mutual inductance data will be used in subsequent system rationalization design. In the operating mode, the mutual inductance between the receiving coil and the transmitting coil is M. i,j Specifically, M can be calculated by combining the following formulas. i,j For parameters not specifically mentioned, existing technologies can be referenced. For example, current intensity and air permeability are determined based on the environment and equipment properties in actual applications. No further restrictions are imposed here. They are calculated based on the properties of the coil and conventional methods in the field.

[0011] Ideally, the transmitting and receiving coils should be parallel to each other, although this is not strictly required in clinical practice. When their planes are not parallel (there is an angle between them), the magnetic flux density generated by the transmitting coil at the receiving coil, which enables mutual inductance and voltage generation, is the component of the magnetic flux density generated by the transmitting coil in the direction normal to the receiving coil plane (i.e., perpendicular to the coil plane). This component enables the receiving coil to generate a voltage, which can be calculated using existing techniques; this situation will not be specifically described here. When the angle between the transmitting and receiving coils is stable, the output power and transmission efficiency are also relatively stable. Therefore, when evaluating the output power and transmission efficiency of the coils in different operating modes in the array, the parallel state of the two coils can be used as a reference value, and component analysis can be performed using existing techniques when necessary. In the analytical model of this invention, when the two coil planes are parallel, the angle between the two coils is 0° or can be interpreted as no angle.

[0012] The following is a mutual inductance analysis based on the parallel surfaces of the two coils, obtaining the mutual inductance strength M of the two coils. i,j The mutual inductance between the receiving coil and the transmitting coil (both coils are parallel) in the operating mode, in practical applications, regardless of its ultimate purpose, should fall within the scope of this invention as long as it is used to analyze the mutual inductance of the pacemaker charging coil and applies the following model:

[0013]

[0014] The magnetic flux density in the direction.

[0015] In practical implementation, when analyzing magnetic flux density, the magnetic flux density vectors in different directions can be analyzed. The magnetic flux density vectors in the X, Y, and Z directions at any point are as follows:

[0016] N Tx For the transmitting coil TX i,j The number of turns, μ0 is the air permeability. For amplitude, θ i,j Let ω be the initial phase and ω be the target operating frequency.

[0017] N Tx For the transmitting coil TX i,j The number of turns, μ0 is the air permeability. For amplitude, θ i,j Let ω be the initial phase and ω be the target operating frequency.

[0018] N Tx For the transmitting coil TX i,j The number of turns, μ0 is the air permeability. For amplitude, θ i,jω is the initial phase, and ω is the target operating frequency.

[0019] Furthermore, in calculating B x | i,j B y | i,j B z | i,j Furthermore, analysis can be performed based on other fundamental parameters. The components of the magnetic flux density at any point of the transmitting coil assembly in the X, Y, and Z directions are respectively B x | i,j B y | i,j B z | i,j :

[0020]

[0021]

[0022] Furthermore, regarding the current in the transmitting coils, the current in any transmitting coil of the transmitting coil group is I. i,j , i and j refer to the transmitting coils corresponding to different rows and columns, respectively.

[0023] The second aspect of this invention provides an output power analysis model for an array-type multi-excitation IPT system for implantable cardiac pacemakers. The array-type multi-excitation IPT system includes a receiving coil and a transmitting coil group consisting of several coplanarly arrayed transmitting coils. The side length of both the receiving and transmitting coils is L. The distance between any two adjacent transmitting coils in the transmitting coil group is d, and -L ≤ d ≤ L. All transmitting coils are located in the XOY plane of the coordinate system, and the coordinates of the four vertices of the transmitting coil in the i-th row and j-th column are...

[0024] Specifically, based on the aforementioned mutual inductance analysis model of any of the array-type multi-excitation IPT systems, the output power of the array-type multi-excitation IPT system is obtained as P0.

[0025] P o =f1(M,U AB ,R Leq ,R s ,L f ),

[0026]

[0027] M pis The mutual inductance M between the receiving coil and transmitting coil groups in the operating mode i,j U ABi R is the AC voltage output of the i-th transmitting inverter circuit.Leq R is the equivalent load resistance. s L is the equivalent internal resistance of the receiving coil. fi The inductor is used as the series compensation inductor for the i-th transmitting terminal. In practical applications, the main variable is the mutual inductance between different transmitting and receiving coils; the parameters of the other coils are the same.

[0028] The third aspect of this invention provides a transmission efficiency analysis model for an array-type multi-excitation IPT system for implantable cardiac pacemakers. The array-type multi-excitation IPT system has a receiving coil and a transmitting coil group consisting of several coplanarly arrayed transmitting coils. The side length of both the receiving and transmitting coils is L. The distance between any two adjacent transmitting coils in the transmitting coil group is d, and -L ≤ d ≤ L. All transmitting coils are located in the XOY plane of the coordinate system. The coordinates of the four vertices of the transmitting coil in the i-th row and j-th column are respectively...

[0029] Among them, based on any of the aforementioned mutual inductance analysis models of array-type multi-excitation IPT systems, the transmission efficiency of the array-type multi-excitation IPT system is η.

[0030] η=f2(M,ω,R Leq ,R p ,R s ,m),

[0031]

[0032] Alternatively, the transmission efficiency η can be obtained based on the output power analysis model of any of the aforementioned array-type multi-excitation IPT systems.

[0033]

[0034] M pis The mutual inductance between the receiving coil and the transmitting coil in the operating mode is M. i,j U ABi R is the AC voltage output of the i-th transmitting inverter circuit. Leq R is the equivalent load resistance. s R is the equivalent internal resistance of the receiving coil. p This is the equivalent internal resistance of the transmitting coil at the transmitting end.

[0035] The fourth aspect of this invention provides the application of the mutual inductance analysis model of any of the aforementioned implantable cardiac pacemaker array-type multi-excitation IPT system in the fabrication of an implantable cardiac pacemaker wireless charging module. Specifically, it can be used to construct an implantable cardiac pacemaker array-type multi-excitation IPT system, which includes a transmitting coil group and a receiving coil and analysis control unit group placed in the implantable cardiac pacemaker.

[0036] The transmitting coil group has a rows of a and b columns of transmitting coils. Both the receiving and transmitting coils have a side length of L. The distance between any two adjacent transmitting coils in the transmitting coil group is d, and -L ≤ d ≤ L. All transmitting coils are located in the XOY plane of the coordinate system. The coordinates of the four vertices of the transmitting coil in the i-th row and j-th column are...

[0037] The analysis and control unit group includes: the output power analysis model of any of the aforementioned array-type multi-excitation IPT systems and the transmission efficiency analysis model of any of the aforementioned array-type multi-excitation IPT systems. The output power analysis model of the array-type multi-excitation IPT system is used to calculate the output power of the transmitting coil group of the array-type multi-excitation IPT system to the receiving coil. The transmission efficiency analysis model of the array-type multi-excitation IPT system is used to calculate the transmission efficiency of the transmitting coil group of the array-type multi-excitation IPT system to the receiving coil.

[0038] Calculate the output power P of the array-type multi-excitation IPT system according to the following formula. o and transmission efficiency η, U pi The voltage of the transmitting coil is the voltage of the transmitting coil. In the transmitting coil group, each transmitting coil working unit consists of any two adjacent rows and two columns of coils (two rows and two columns form a regular quadrilateral; in analysis and evaluation, this can be considered as one working unit, and the charging mode can be adjusted by regulating the working mode of this unit). Of course, if more than four working units are used, but the analysis of P... o And the transmission efficiency η still includes the analysis of the four coil working units, which should also be within the scope of this invention. Calculate the received power P at any position in the receiving coil plane under the three modes in this transmitting coil working unit. 1-coil ,P 2-coil ,P 4-coil and transmission efficiency η 1-coil ,η 2-coil ,η 4-coil :

[0039] Operating mode one, when one coil in the transmitting coil operating unit is working:

[0040]

[0041] Operating mode two: When only any two adjacent coil edges in the transmitting coil unit are operating:

[0042]

[0043] Operating mode three, when all four coils in the transmitting coil unit are working:

[0044]

[0045] When any mode satisfies the following requirement, the array-type multi-excitation IPT system mutual inductor system operates in that mode:

[0046]

[0047] Among them, P target For the target output power, P 1-coil ,P 2-coil ,P 4-coil These represent the received power at any position within the receiving coil plane under the three modes, I. pi I is the current in the transmitting coil. max For the maximum current allowed through the Litz line, U pi U is the voltage of the transmitting coil. max The breakdown voltage of the Litz wire of the transmitting coil is given. All four parameters can be determined according to the application scenario and are determined by the properties of the coil. When the coil is defined, they are constant values.

[0048] In the case of an implantable cardiac pacemaker array-type multi-excitation IPT system, the analysis and control unit group can calculate P based on the parameters between the receiving coil and transmitting coil groups respectively. 1-coil-xy ,P 2-coil-xy ,P 4-coil-xy ≥ and η 1-coil ,η 2-coil ,η 4-coil When three modes P 1-coil-xy ,P 2-coil-xy ,P 4-coil-xy Any one greater than P target When its transmission power is the highest among the three, the corresponding working mode of the implantable cardiac pacemaker array multi-excitation type IPT system is adopted.

[0049] The fifth aspect of this invention provides a coil design method for an implantable cardiac pacemaker array-type multi-excitation IPT system, comprising the following steps:

[0050] S1. Determine the size of the transceiver coil and the transmission distance, set the target output power of the IPT system, and adjust the optimal overlap distance between adjacent coils using finite element analysis. The overlap distance can also be understood as the distance d between two adjacent coils (when the coils overlap, the distance between them -L≤d<0). The size of the transceiver coil and other parameters can be treated as constants here, and they are not considered as objects affected by the spacing. Finite element analysis is a conventional existing technology and will not be elaborated on further. The transmission distance can be obtained by measuring using existing methods.

[0051] S2. Based on the aforementioned output power analysis model of any array-type multi-excitation IPT system and the aforementioned transmission efficiency analysis model of any array-type multi-excitation IPT system, calculate the received power and transmission efficiency at different locations corresponding to different transmitting coil operating modes:

[0052]

[0053] P0 and η can be analyzed and calculated using the aforementioned model formula. The parameters not detailed here are fixed properties of the coil. When the coil is determined, these parameters can be considered fixed values ​​and can be determined in practical applications. They will not be elaborated on here.

[0054] S3. By comparing whether the single-transmitter coil mode has the highest transmission efficiency among the three transmitting coil operating modes under the premise of meeting the target power, if it does, then this area is the effective power supply area for the single-transmitter coil operating mode; or, by comparing whether the dual-transmitter coil mode has the highest transmission efficiency among the three transmitting coil operating modes under the premise of meeting the target power, if it does, then this area is the effective power supply area for the dual-transmitter coil operating mode; or, by comparing whether the transmission efficiency of the four-transmitter coil operating mode is greater than the standard target transmission efficiency under the premise of meeting the charging power, if it does, then this area is the effective charging area for the four-transmitter coil operating mode.

[0055] In use, the center point of the receiving coil can be used as the analysis object to analyze its state in the magnetic field of the transmitting coil. Alternatively, the states of other points of the receiving coil in the magnetic field of the transmitting coil can be used as the analysis model, and existing technologies can be used to determine the center point position. If none of the three transmission modes meet the target power or the highest transmission efficiency among the three modes does not meet the target transmission efficiency, then return to step S1. It should be noted that the order of numerical comparison among the three operating modes is not particularly limited; any comparison to obtain a preferred solution should be within the scope of this invention.

[0056] This disclosure employs an array-type multi-transmitter coil wireless power transfer technology, significantly improving the stability of power transmission in cardiac pacemakers, ensuring continuous and stable power supply even when the patient's position changes. Furthermore, this technology extends the effective transmission distance and coverage, ensuring effective power transmission over long distances and in complex human tissue environments. By flexibly controlling power transmission, the operating state of the transmitter coils can be adjusted according to the actual needs of the pacemaker, thereby improving power transmission efficiency and extending system lifespan. Simultaneously, this technology enhances the adjustability of the coupling coefficient; by optimizing coil parameters to adjust the coupling effect, it further improves power transmission efficiency, providing a solid guarantee for the stable operation of the cardiac pacemaker. Attached Figure Description

[0057] Figure 1 A wireless power supply system for implantable cardiac pacemakers based on arrayed coils;

[0058] Figure 2 The equivalent circuit of an array-type multi-excitation IPT system;

[0059] Figure 3 A calculation model for the magnetic field of an array of multiple transmitting coils;

[0060] Figure 4 Flowchart for the design of the charging area of ​​an array-type multi-excitation IPT system;

[0061] Figure 5 The output power distribution is a 2×2 array with multiple transmitting coils.

[0062] Figure 6 The transmission efficiency distribution of a 2×2 array-type multi-transmitter coil array;

[0063] Figure 7 The effective working area for different transmitting coil operating modes. Detailed Implementation

[0064] The invention will be further described below with reference to a research example from this study.

[0065] (I) Overall System Design

[0066] Installing an array of multi-transmitter coils in a person's standing (or lying) area exposes the entire person to a high-intensity alternating magnetic field. Excessive electromagnetic field strength may interfere with the pacemaker's electronic components and even pose a potential risk of thermal damage to human tissue. Furthermore, if the wireless power transmission system malfunctions, such as a sudden increase in transmission power, it could seriously endanger the patient's health. Therefore, the array of multi-transmitter coils is installed facing the patient. Because different patients have varying heights, the installation height varies, resulting in changes in the relative positions of the transmitting and receiving coils at the receiving end.

[0067] Wireless power supply system for implantable cardiac pacemakers based on arrayed coils, such as Figure 1 As shown, the circuit is powered by a DC power supply, the inverter converts the DC power into AC power, and after passing through a compensation network, it is transmitted to the IPT coil (including the primary and secondary coils) and the secondary side. The contactless transmission of electrical energy is achieved through magnetic field coupling between the primary and secondary coils.

[0068] Magnetic couplers are a key component of IPT systems. The most common coupling coil structures in IPT systems are square, circular, and polygonal. However, splicing circular coils can easily create magnetic field voids, and the edge magnetic field regions of circular and polygonal coils are difficult to control. Therefore, square coils are chosen as the smallest working unit for multiple transmitting coils in array-type multi-excitation IPT systems. Using coils of the same size and structure in array-type multi-excitation IPT systems facilitates standardization and system expansion. The receiving coil has the same structure and size as a single transmitting coil, making it easy to replace and upgrade different transmitting and receiving coils, improving system compatibility. This also reduces inventory types and manufacturing costs during maintenance and replacement, improving maintenance convenience.

[0069] Therefore, array-type multi-excitation IPT systems are designed with single-transmitter coil, dual-transmitter coil, and quad-transmitter coil operating modes to improve the IPT system's anti-offset performance. The single-transmitter coil operating mode is the basic operating unit of the array-type multi-excitation IPT system, but its anti-offset performance is limited. The adjacent dual-transmitter coil operating mode helps reduce magnetic field loss in the coil edge region, making energy transmission more concentrated and improving the overall system efficiency. The matrix-type quad-transmitter coil operating mode can form a more uniform magnetic field distribution, improving system transmission efficiency and anti-offset capability; it provides greater spatial freedom, allowing the receiver to operate in a wider area without affecting energy reception; and by adjusting the output of each transmitter coil, it better adapts to changes in load location and power supply requirements, maintaining stable energy transmission of the IPT system.

[0070] (II) Performance Analysis of Array-type Multi-excitation IPT System

[0071] Arrayed multi-transmitter coils minimize cross-coupling between coils by overlapping adjacent emitter coils, thus the mutual inductance between arrayed multi-transmitter coils can be ignored. The equivalent circuit of an arrayed multi-excitation IPT system is as follows: Figure 2 As shown. According to Figure 2 It can be known that U dc To provide DC power to the transmitter, U ABm L is the AC voltage output of the m-th transmitting inverter circuit. pm L is the self-inductance of the transmitting coil at the m-th transmitting end. fm For the series compensation inductor of the m-th transmitter, C fm For the m-th transmitter, a parallel compensation capacitor, C pm For the m-th transmitter, series compensation capacitor C s For the receiving end, a series compensation capacitor, L s R is the self-inductance of the receiving coil. pm R is the equivalent internal resistance of the m-th transmitting coil at the transmitting end. s R is the equivalent internal resistance of the receiving coil. Leq This is the equivalent load resistance.

[0072] Based on Kirchhoff's laws, the circuit equations of the array-type multi-excitation IPT system are established, as shown in equation (1).

[0073]

[0074] Then the impedance Z on the transmitting and receiving sides p Z s As shown in equation (2).

[0075]

[0076] The resonant frequency ω of the array-type multi-excitation IPT system under resonant conditions satisfies the following formula (3).

[0077]

[0078] Therefore, the compensation inductor current I can be obtained. fi The current I in the transmitting coil pi Receiver coil current I s As shown in equation (4).

[0079]

[0080] According to equation (4) above, the output power P of the array-type multi-excitation IPT system is obtained. o As shown in equation (5).

[0081]

[0082] When the inverter output voltage of each channel in an array-type multi-excitation IPT system is consistent, that is: U AB1 =U AB2 =…=U ABm Considering only the power losses of the primary and secondary coils of the IPT system, the output power P of the multi-excitation IPT system is... o The transmission efficiency η is shown in Equations (6) and (7), respectively.

[0083]

[0084] According to the above formula, once the input voltage and resonant network device parameters of the IPT system are determined, the output power P of the IPT system... o Mainly related to the mutual inductance M between the coupling coils pis Related. The transmission efficiency η of an array-type multi-excitation IPT system is not only related to the mutual inductance M between the coupled coils. pis It is also related to the number of transmitting coils.

[0085] (III) Working Area Division Method for Array-type Multi-excitation IPT System

[0086] (3.1) Calculation model of mutual inductance between transmitting and receiving coils

[0087] In array-type multi-excitation IPT systems, the mutual inductance between the transmitting and receiving coils is a key factor affecting the received power and transmission efficiency of the array-type multi-excitation IPT system under different transmitting coil operating modes.

[0088] Once the dimensions of the coupling coil structure are determined, the range of motion of the receiving coil to meet charging requirements is limited. Furthermore, the position of each implanted pacemaker patient within the charging area is difficult to maintain completely. Therefore, it is necessary to calculate the mutual inductance change between the transmitting and receiving coils at any charging position based on the actual coupling coil dimensions (determined according to clinical needs), thus enabling the division of the charging area in various operating modes of the array-type multi-excitation IPT system. The mutual inductance parameters between the two current-carrying conductors are calculated using the Neumann formula, where the planar transmitting coil is assumed to be a constant current conductor, and its mutual inductance value mainly depends on the size parameters of the transmitting and receiving coils and their relative positions.

[0089] like Figure 3 The diagram shows an array of multiple transmitting coils. Each square transmitting coil has a side length of L. The receiving coil has the same dimensions as the transmitting coil, with a side length of L. d represents the spacing between adjacent transmitting coils, where -L ≤ d ≤ L. Figure 3 Based on the coordinate system shown, all transmitting coils are located on the XOY plane, and the coordinates of the four vertices of the transmitting coil in the i-th row and j-th column are shown in Equation (8).

[0090]

[0091] by Figure 3 The current I in the transmitting coil of the second row and first column is... i,j From A i,j Flowing through B i,j C i,j D i,j For example, P i,j (x i,j ,y i,j ,z i,j Given a point P(x,y,z) located at any point on an array of multiple transmitting coils, and a random point P(x,y,z) being any point on a receiving coil, then point P... i,j The vector to point P is As shown in equation (9).

[0092]

[0093] In the formula These are the unit vectors in the X, Y, and Z directions, respectively. Transmitting coil TX i,j Current I in i,j As shown in equation (10).

[0094]

[0095] In the formula For amplitude, θ i,j Let ω be the initial phase and ω be the target operating frequency. Based on the Biot-Savart law and equations (8) to (10), the transmitting coil TX is used at point P(x,y,z). i,j The resulting magnetic induction intensity B i,j As shown in equation (11).

[0096]

[0097] In the formula N Tx For the transmitting coil TX i,j The number of turns, μ0 is the air permeability. B i,j Includes B x | i,j B y | i,j B z | i,j The three components are shown in equations (12) to (14). The magnetic flux density B at point P(x,y,z) is composed of the magnetic induction intensity generated by the m rows and n columns of the transmitting coils, i.e., m×n transmitting coils, as shown in the following equation.

[0098]

[0099]

[0100] The mutual inductance M between single-turn square coils is shown in equation (16).

[0101]

[0102] In the formula, S represents the area of ​​the receiving coil, and I represents the current in the transmitting coil. Based on the superposition principle, the mutual inductance M between a single-transmitter multi-turn coil can be obtained. single-coil As shown in equation (17).

[0103]

[0104] M mn N is the mutual inductance between the m-th turn of the transmitting coil and the n-th turn of the receiving coil. Tx N is the number of turns in the transmitting coil. Rx It refers to the number of turns of the receiving coil.

[0105] Therefore, in the array-type multi-transmitter coil operating mode, the mutual inductance M between the transmitting and receiving coils is... i,j As shown in equation (18).

[0106]

[0107] M i,j This represents the mutual inductance between the transmitting and receiving coils, which have a total of i rows and j columns. 'a' is the number of rows in the array-type multi-excitation IPT system, and 'b' is the number of columns in the array-type multi-excitation coil.

[0108] (3.2) Charging area division strategy design

[0109] According to equations (16) to (18), the output power P of the array-type multi-excitation IPT system is... o The transmission efficiency η is shown in equation (19).

[0110]

[0111] Once the number and size of the transmitting coils are determined, the pacemaker implantation site on the human body is charged on the charging platform, and the transmission distance between the transmitting and receiving coils remains unchanged. The mutual inductance between the transmitting and receiving coils under different transmitting coil operating modes (single-transmitter, dual-transmitter, and quad-transmitter) can be calculated using equations (16) to (18).

[0112] In order to achieve high transmission efficiency of the IPT system while meeting the target output power, the determination condition of the charging area is as shown in Equation (20).

[0113]

[0114] P target For the target output power, P 1-coil ,P 2-coil ,P 4-coil These represent the received power at any position within the receiving coil plane under the three modes, I. pi I is the current in the transmitting coil. max For the maximum current allowed through the Litz line, U pi U is the voltage of the transmitting coil. max P is the breakdown voltage of the Litz wire in the transmitting coil. 1-coil-xy ,P 2-coil-xy ,P 4-coil-xy ≥P target Used to determine the boundary of the charging area, η 1-coil ,η 2-coil ,η 4-coil ≥η target The transmission efficiency under the transmitting coil operating mode is determined to be greater than the target transmission efficiency. When the parameters of the given array-type multi-excitation IPT system satisfy the above equation (20), the region is an effective charging region; otherwise, it is an ineffective charging region.

[0115] This article aims to achieve the target output power P of the IPT system. targetWith this as the primary objective, and selecting the most efficient operating mode among different transmitting coil operating modes, a flowchart was designed to determine the effective charging area of ​​the array-type multi-excitation IPT system under different operating modes, as follows: Figure 4 As shown.

[0116] The method for determining the charging region in an array-type multi-excitation IPT system under different transmitting coil operating modes is as follows:

[0117] A. Determine the transceiver coil size and transmission distance based on the application scenario and the shape of the charging equipment, and set the target output power P of the IPT system. target The optimal overlap distance between adjacent coils is adjusted by combining finite element analysis calculations.

[0118] B. In the process of determining the charging area, a circuit and mutual inductance analysis model of the array-type multi-excitation IPT system is established, and the received power and transmission efficiency corresponding to different transmitting coil working modes at different locations are derived.

[0119]

[0120] C. By comparing whether the single-transmitter coil mode has the highest transmission efficiency among the three transmitter coil operating modes while meeting the target power, this area is the effective power supply area for the single-transmitter coil operating mode; by comparing whether the dual-transmitter coil mode has the highest transmission efficiency among the three transmitter coil operating modes while meeting the target power, this area is the effective power supply area for the dual-transmitter coil operating mode; for the four-transmitter coil operating mode, under the premise of meeting the charging power, the transmission efficiency must be greater than the standard target transmission efficiency η. target This refers to the effective charging area in the four-emitting-coil operating mode.

[0121] (3.3) Simulation Result Analysis

[0122] The research is based on the assumption that the outer diameter of both the transmitting and receiving coils is 300mm*300mm, the inner diameter is 100mm*100mm, and the spacing between the transmitting and receiving coils is 100mm. Simulations were used to obtain the output power of three 2×2 array multi-transmitter coils under different transmitting coil operating modes, such as... Figure 5 As shown. Among them. Figure 5 Figure (a) shows a summary diagram of the individual operating output power distribution of transmitting coils TX1, TX2, TX4, and TX5 in a 2×2 array multi-transmitter coil. Figure 5 Figure (b) is a summary diagram of the output power distribution in different dual-transmitter coil operating modes TX1+TX2, TX2+TX5, TX1+TX4, and TX4+TX5 in a 2×2 array multi-transmitter coil system. Figure 5(c) is the output power distribution diagram of the four-transmitter coil working mode TX1+TX2+TX4+TX5 in the 2×2 array multi-transmitter coil.

[0123] The transmission efficiency of a 2×2 array multi-transmitter coil under three different transmitting coil operating modes was obtained through simulation, such as... Figure 6 As shown. Among them. Figure 6 Figure (a) is a summary diagram of the individual transmission efficiency distribution of transmitting coils TX1, TX2, TX4, and TX5 in a 2×2 array multi-transmitter coil. Figure 6 Figure (b) is a summary diagram of the transmission efficiency distribution for different dual-transmitter coil operating modes TX1+TX2, TX2+TX5, TX1+TX4, and TX4+TX5 in a 2×2 array multi-transmitter coil system. Figure 6 (c) is a diagram showing the transmission efficiency distribution of four-transmitter coils (TX1+TX2+TX4+TX5) in a 2×2 array multi-transmitter coil system.

[0124] In the single-transmitter coil operating mode, there is a significant mutual inductance drop in the middle region and adjacent side regions of the transmitter coil, but the transmission efficiency is relatively high around the center point of the transmitter coil. The dual-transmitter coil operating mode effectively compensates for the mutual inductance drop in the adjacent side regions of the single-transmitter coil operating mode, but a significant mutual inductance drop exists in the middle region of the transmitter coil, resulting in a slightly lower transmission efficiency compared to the single-transmitter coil operating mode. The four-transmitter coil operating mode effectively compensates for the mutual inductance drop in the middle region of the 2×2 array of multiple transmitter coils, but its overall transmission efficiency is not high. Therefore, the effective range for achieving the rated output power under these three transmitter coil operating modes can be obtained, such as... Figure 7 As shown, under the premise that the basic parameters of each single coil are consistent, the area with a power greater than 300W in the single-transmitter coil operating mode is four circles with a diameter of 120mm centered on the center of each transmitting coil. The area with a transmission efficiency greater than 80% is approximately a circle with a radius of 240mm. This indicates that the effective charging area of ​​the single-transmitter coil operating mode is the four circles with a diameter of 120mm centered on the center of each transmitting coil. The dual-transmitter coil operating mode effectively compensates for the mutual inductance drop in the middle area between adjacent transmitting coils. The transmission efficiency at the center of both adjacent transmitting coils is greater than 80%, thus indicating that the effective charging area of ​​the dual-transmitter coil operating mode is the middle area between adjacent transmitting coils. However, mutual inductance drop still exists in the middle part of the dual-transmitter coil working mode, so a four-transmitter coil working mode is required. The four-transmitter coil working mode can form a fully effective working area with significant advantages in both transmission power and efficiency within a rectangular range of at least 214mm. In this simulation experiment, with the outer diameter of the transceiver coil being 300mm*300mm, the inner diameter of the transceiver coil being 100mm*100mm, and the interval between the transceiver coils being 100mm, the overlap distance of the dual-transmitter and four-transmitter modes is 90mm.

[0125] Those skilled in the art will appreciate that various modifications to the above embodiments can be made without departing from the overall spirit and concept of the present invention. For any aspects not detailed herein, reference can be made to the prior art. All such modifications fall within the protection scope of the present invention. The protection scheme of the present invention is defined by the appended claims.

Claims

1. A mutual inductance analysis model for an implantable cardiac pacemaker array-type multi-excitation IPT system, characterized in that: An array-type multi-excitation IPT system comprises a transmitter coil group consisting of several coplanar arrayed transmitter coils and a receiver coil placed inside the body to charge the power supply within the pacemaker. Both the transmitter and receiver coils have a side length of L. The distance between any two adjacent transmitter coils in the transmitter coil group is d, and -L ≤ d ≤ L. All transmitter coils are located in the XOY plane of the coordinate system. The coordinates of the four vertices of the transmitter coil in the i-th row and j-th column are... The analysis model includes the following formulas: In the formula: a is the number of rows in the array-type multi-excitation IPT system, b is the number of columns in the array-type multi-excitation coil group, and M is the number of columns in the array-type multi-excitation coil group. i,j M represents the mutual inductance between the transmitting and receiving coils, which have a total of i rows and j columns. single-coil For mutual inductance between single-emitter multi-turn coils, N Tx N is the number of turns in the transmitting coil. Rx M is the number of turns of the receiving coil. mn Let m be the mutual inductance between the m-th turn of any transmitting coil and the n-th turn of any receiving coil; B is composed of the magnetic induction intensity generated by the transmitting coils (a rows and b columns) at the same point, where a is the number of rows and b is the number of columns in the transmitting coil group. x|i,j Let B be the magnetic flux density of the coil in the i-th row and j-th column at any point in the X direction. y|i,j Let B be the magnetic flux density of the coil in the i-th row and j-th column at any point in the Y direction. z|i,j M represents the magnetic flux density of the coil in the i-th row and j-th column at any point in the Z direction; i,j This refers to the mutual inductance between the receiving coil and the transmitting coil in the operating mode.

2. The mutual inductance analysis model of the implantable cardiac pacemaker array-type multi-excitation IPT system according to claim 1, characterized in that: The magnetic flux density vectors in the X, Y, and Z directions at any point are as follows: N Tx For the transmitting coil TX i,j The number of turns, μ0 is the air permeability. For amplitude, θ i,j Let ω be the initial phase and ω be the target operating frequency. N Tx For the transmitting coil TX i,j The number of turns, μ0 is the air permeability. For amplitude, θ i,j Let ω be the initial phase and ω be the target operating frequency. N Tx For the transmitting coil TX i,j The number of turns, μ0 is the air permeability. For amplitude, θ i,j ω is the initial phase, and ω is the target operating frequency.

3. The mutual inductance analysis model of the implantable cardiac pacemaker array-type multi-excitation IPT system according to claim 2, characterized in that: The components of the magnetic flux density at any point in the transmitting coil assembly in the X, Y, and Z directions are respectively B x | i,j B y | i,j B z | i,j :

4. The mutual inductance analysis model of the implantable cardiac pacemaker array-type multi-excitation IPT system according to claim 3, characterized in that: The current in any transmitting coil of the transmitting coil group is I i,j , 5. An output power analysis model for an implantable cardiac pacemaker array-type multi-excitation IPT system, characterized in that: An array-type multi-excitation IPT system has a receiving coil and a transmitting coil group consisting of several transmitting coils arranged in a coplanar array. The side length of both the receiving and transmitting coils is L. The distance between any two adjacent transmitting coils in the transmitting coil group is d, and -L ≤ d ≤ L. All transmitting coils are located in the XOY plane of the coordinate system. The coordinates of the four vertices of the transmitting coil in the i-th row and j-th column are... Wherein, based on the mutual inductance analysis model of the array-type multi-excitation IPT system according to any one of claims 1 to 4, the output power of the array-type multi-excitation IPT system is P0. P o =f1(M,U AB ,R Leq ,R s ,L f ), M pis The mutual inductance M between the receiving coil and transmitting coil groups in the operating mode i,j U ABi R is the AC voltage output of the i-th transmitting inverter circuit. Leq R is the equivalent load resistance. s L is the equivalent internal resistance of the receiving coil. fi The inductor is connected in series to compensate for the i-th transmitter.

6. A transmission efficiency analysis model for an implantable cardiac pacemaker array-type multi-excitation IPT system, characterized in that: An array-type multi-excitation IPT system has a transmitter coil group consisting of several coplanar arrayed transmitter coils and a receiver coil for charging the internal power supply of the pacemaker. Both the transmitter and receiver coils have a side length of L. The distance between any two adjacent transmitter coils in the transmitter coil group is d, and -L ≤ d ≤ L. All transmitter coils are located in the XOY plane of the coordinate system. The coordinates of the four vertices of the transmitter coil in the i-th row and j-th column are... Among them, based on the mutual inductance analysis model of the array-type multi-excitation IPT system according to any one of claims 1 to 4, the transmission efficiency of the array-type multi-excitation IPT system is η. η=f2(M,ω,R Leq ,R p ,R s ,m), Alternatively, the transmission efficiency η can be obtained based on the output power analysis model of the array-type multi-excitation IPT system in claim 5. M pis The mutual inductance between the receiving coil and the transmitting coil in the operating mode is M. i,j U ABi R is the AC voltage output of the i-th transmitting inverter circuit. Leq R is the equivalent load resistance. s R is the equivalent internal resistance of the receiving coil. p This is the equivalent internal resistance of the transmitting coil at the transmitting end.

7. The application of the mutual inductance analysis model of the implantable cardiac pacemaker array multi-excitation IPT system according to any one of claims 1 to 4 in the preparation of the wireless charging module for the implantable cardiac pacemaker.

8. An implantable cardiac pacemaker array-type multi-excitation IPT system, characterized in that, It includes a transmitting coil assembly, an analysis and control unit assembly, and a receiving coil for charging the internal power supply of the heart pacemaker when placed inside the body; The transmitting coil group has a rows of a and b columns of transmitting coils. Both the receiving and transmitting coils have a side length of L. The distance between any two adjacent transmitting coils in the transmitting coil group is d, and -L ≤ d ≤ L. All transmitting coils are located in the XOY plane of the coordinate system. The coordinates of the four vertices of the transmitting coil in the i-th row and j-th column are... The analysis and control unit group includes: the output power analysis model of the array-type multi-excitation IPT system as described in claim 5 and the transmission efficiency analysis model of the array-type multi-excitation IPT system as described in claim 6. The output power analysis model of the array-type multi-excitation IPT system is used to calculate the output power of the transmitting coil group of the array-type multi-excitation IPT system to the receiving coil, and the transmission efficiency analysis model of the array-type multi-excitation IPT system is used to calculate the transmission efficiency of the transmitting coil group of the array-type multi-excitation IPT system to the receiving coil. Calculate the output power P of the array-type multi-excitation IPT system according to the following formula. o and transmission efficiency η, U pi This is the voltage of the transmitting coil. In a transmitting coil working unit consisting of any two adjacent rows and two columns of coils, calculate the received power P at any position within the receiving coil plane under three modes. 1-coil ,P 2-coil ,P 4-coil and transmission power η 1-coil ,η 2-coil ,η 4-coil : Operating mode one, when one coil in the transmitting coil operating unit is working: Operating mode two, when only any two adjacent coils in the transmitting coil unit are working: Operating mode three, when all four coils in the transmitting coil unit are working: When any mode satisfies the following requirement, the array-type multi-excitation IPT system mutual inductor system operates in that mode: P target For the target output power, P 1-coil ,P 2-coil ,P 4-coil These represent the received power at any position within the receiving coil plane under the three modes, I. pi I is the current in the transmitting coil. max For the maximum current allowed through the Litz line, U pi U is the voltage of the transmitting coil. max This is the breakdown voltage of the Litz wire in the transmitting coil.

9. The implantable cardiac pacemaker array-type multi-excitation IPT system according to claim 8, characterized in that, The analysis and control unit can calculate P based on the parameters between the receiving coil and the transmitting coil group respectively. 1-coil-xy ,P 2-coil-xy ,P 4-coil-xy ≥ and η 1-coil ,η 2-coil ,η 4-coil When P 1-coil-xy ,P 2-coil-xy ,P 4-coil-xy Any one greater than P target When its transmission power is the highest among the three, the corresponding working mode of the implantable cardiac pacemaker array multi-excitation type IPT system is adopted.

10. A coil design method for an array-type multi-excitation IPT system for implantable cardiac pacemakers, characterized in that, Includes the following steps: S1. Determine the size of the transceiver coil and the transmission distance, set the target output power of the IPT system, and adjust the optimal overlap distance between adjacent coils based on finite element calculations. S2. Based on the output power analysis model of the array-type multi-excitation IPT system in claim 5 and the transmission efficiency analysis model of the array-type multi-excitation IPT system in claim 6, calculate the received power and transmission efficiency under different positions and corresponding transmitting coil operating modes: S3. By comparing whether the single-transmitting coil mode has the highest transmission efficiency among the three transmitting coil operating modes under the premise of meeting the target power, if it does, then this area is the effective power supply area of ​​the single-transmitting coil operating mode. Compare whether the dual-transmitter coil mode has the highest transmission efficiency among the three transmitting coil operating modes under the premise of meeting the target power. If it does, then this area is the effective power supply area of ​​the dual-transmitter coil operating mode. Compare whether the transmission efficiency of the four-transmitter coil operating mode is greater than the standard target transmission efficiency under the premise of meeting the charging power. If it does, then this area is the effective charging area of ​​the four-transmitter coil operating mode. If none of the three transmitting modes meet the target power or the highest transmission efficiency among the three transmitting modes does not meet the target transmission efficiency, then return to step S1.

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