Method for evaluating electromagnetic safety of dynamic implantable wireless power transmission system to human body

Abstract

The present invention belongs to the technical field of research on electromagnetic radiation of implantable wireless power transmission, and particularly relates to a method for evaluating the electromagnetic safety of a dynamic implantable wireless power transmission system for the human body, including the following steps: establishing a human body and its tissue and organ models; establishing a dynamic implantable wireless power transmission coil model; placing the dynamic implantable wireless power transmission model at different positions of the human body and its tissue and organ models at the same displacement angle θ to explore the electromagnetic radiation of the dynamic implantable wireless power transmission coil to the human body at different positions of the human body but with the same motion form; placing the transmission coil models at different displacement angles θ at the same position of the human body model to explore the electromagnetic radiation of the dynamic implantable wireless power transmission coil to the human body at the same position of the human body but with different motion forms; according to the obtained current density J rms and specific absorption rate SAR values, conduct an electromagnetic safety evaluation of the dynamic implantable wireless power transmission system for the human body.

Description

Technical Field

[0001] The present invention belongs to the technical field of research on electromagnetic radiation of implantable wireless power transmission, and specifically relates to a method for evaluating the electromagnetic safety of a dynamic implantable wireless power transmission system on the human body. Background Art

[0002] Wireless power transmission is convenient and safe, but its potential electromagnetic radiation also threatens human health. In particular, the high-frequency resonance generated by the wireless power transmission system has enough energy to destroy chemical bonds, thereby damaging the genetic factors of human cells and causing diseases such as cancer or congenital malformations. Therefore, it is very necessary to explore the impact of implantable wireless power transmission systems on the electromagnetic safety of the human body.

[0003] The Chinese invention patent "A vehicle electromagnetic environment simulation method" (publication number: CN112149223A) discloses an electromagnetic environment simulation method for key positions of a vehicle. The vehicle simulation model is built using CTS simulation software, the excitation source is set, and the simulation results at different positions in the three-dimensional space of the vehicle are observed. The simulation results obtained according to this method are more comprehensive, which reduces the vehicle research and development costs. However, this method only involves the study of the entire vehicle and cannot perform a specific electromagnetic radiation assessment on a certain interference source, which brings difficulties to the subsequent measures to reduce electromagnetic radiation interference; the Chinese invention patent "A ring coil electromagnetic radiation prediction method based on resonant wireless power transmission" (publication number: CN107482797A) discloses a ring coil electromagnetic radiation prediction method based on resonant wireless power transmission. By simulating various states of the system transmission coil, the magnetic field distribution around the coil is extracted to obtain the system electromagnetic radiation prediction value. This method provides a reference for optimizing the system design from the interference source to reduce the system electromagnetic radiation, but the invention only involves static transmission coils and does not consider the influence of the coil motion state on electromagnetic radiation.

[0004] At present, the electromagnetic safety assessment of implantable wireless power transmission systems to the human body is rarely mentioned in domestic and foreign literature, especially the research on dynamic implantable transmission coils has not been found so far. Summary of the invention

[0005] The present invention overcomes the shortcomings of the prior art and provides a method for evaluating the electromagnetic safety of a dynamic implantable wireless power transmission system to the human body. The method can more comprehensively and accurately conduct in-depth research on the electromagnetic radiation interference of the motion state of the wireless power transmission coil. At the same time, the method provides a powerful reference for the design of the coil of the dynamic implantable wireless power transmission system and the subsequent measures to reduce the electromagnetic interference of the system.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A method for evaluating the electromagnetic safety of a dynamic implantable wireless power transmission system on a human body comprises the following steps:

[0008] S1. Establish a model of the human body and its tissues and organs;

[0009] S2. Establish a dynamic implantable wireless power transmission coil model in the electromagnetic simulation system simulation environment, wherein the dynamic implantable wireless power transmission coil model includes: a transmitting coil model and a receiving coil model, and establish a dynamic implantable wireless power transmission coil model under different displacement angles θ, where θ can be 0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, and 90°;

[0010] S3, importing the human body and its tissue and organ models in step S1 into the electromagnetic simulation system simulation software;

[0011] S4, placing the dynamic implantable wireless power transmission model under the same displacement angle θ established in step S2 at different positions of the human body and its tissue and organ model, exploring the electromagnetic radiation of the dynamic implantable wireless power transmission coil to the human body at different positions of the human body but under the same motion form, and obtaining the current density J of each tissue, organ and part of the human body rms , according to the following formula (1) and formula (2), calculate the value of specific absorption rate SAR,

[0012]

[0013]

[0014] Among them, σ is the magnetic permeability of human tissues and organs, ρ is the density of human tissues and organs, J rms is the effective value of current density, E rms It is the effective value of the field strength in the human tissue and organ area;

[0015] S5. Place the transmission coil model under different displacement angles θ established in step S2 at the same position of the human body model, explore the electromagnetic radiation of the dynamic implantable wireless power transmission coil to the human body under the same position of the human body but different motion forms, and obtain the current density J of various tissues, organs and parts of the human body. rms , according to formula (1) and formula (2), calculate the value of specific absorption rate SAR;

[0016] S6. According to the current density J obtained in step S4 and step S5 rms And specific absorption rate SAR value, to evaluate the electromagnetic safety of dynamic implantable wireless power transmission system to the human body.

[0017] Furthermore, in step S1, 3D animation is used to model the human body and its tissues and organs. A reference cube is selected in the 3D animation software, the human torso is drawn, the cube is meshed according to the human body proportions, the cube is selected, and the option to convert it to "editable polygon" is selected; by adding auxiliary lines, according to the structural characteristics of the human body, combined with the front view and the side view, the selected surface is stretched or compressed to make the model lines fuller and the character tends to be three-dimensional, and the same method is used to draw a human tissue and organ model according to biological proportions.

[0018] Furthermore, the transmitting coil model includes the following parameters: the number of transmitting coil turns, the transmitting coil radius, the transmitting coil turn spacing, and the transmitting coil cross-sectional current; the receiving coil model includes the following parameters: the number of receiving coil turns, the receiving coil radius, the receiving coil turn spacing, and the receiving coil cross-sectional current.

[0019] Furthermore, in step S2, a method for establishing a dynamic implantable wireless power transmission coil model under different displacement angles θ is as follows: combining the transmitting coil model and the receiving coil model into a simulation file, and in the xyz space rectangular coordinate system, setting the distance between the transmitting coil model and the receiving coil model along the z-axis direction to d, the distance d can be determined according to the actual simulation situation, and setting the displacement angle θ between the transmitting coil and the receiving coil.

[0020] Furthermore, in step S5, the displacement angle θ between the transmitting coil and the receiving coil is set to 0°, 30°, 60°, and 90°, because when the displacement angle θ changes in steps of 30°, the simulation data changes appropriately, which is more conducive to reflecting the results.

[0021] Compared with the prior art, the present invention has the following beneficial effects.

[0022] 1. The present invention provides a method for evaluating the electromagnetic safety of a dynamic implantable wireless power transmission system on the human body. The method uses modeling of the human body and its tissues and organs, dynamic coil modeling, and joint simulation of the coil and human body model, which can more comprehensively and accurately study the impact of the motion state of the wireless power transmission coil on electromagnetic radiation interference.

[0023] 2. The present invention can evaluate the electromagnetic safety of an implantable wireless power transmission system before it is put into production, saving the testing costs in the production process, making up for the shortcomings of difficult detection and high cost in actual electromagnetic safety tests of implantable wireless power transmission systems, effectively reducing research costs and improving research efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below in conjunction with the accompanying drawings.

[0025] Figure 1 is a flow chart of the present invention;

[0026] Figure 2 It is an electromagnetic joint simulation diagram of the human body and its tissue and organ model and the dynamic implantable wireless power transmission coil of the present invention;

[0027] Figure 3 A simulation diagram of a human body and its main organ models when performing step S5;

[0028] Figure 4 A simulation diagram of a human body and its main organ models when performing step S4;

[0029] Figure 5 A graph showing changes in SAR values ​​of a human body and its main organ models when performing step S5;

[0030] Figure 6 The SAR value variation diagram of the human body and its main organ models when performing step S4. DETAILED DESCRIPTION

[0031] The present invention is further described below in conjunction with specific embodiments.

[0032] like Figure 1 As shown, the method for evaluating the electromagnetic safety of a dynamic implantable wireless power transmission system to a human body comprises the following steps:

[0033] S1. Establish a model of the human body and its tissues and organs. Use 3D animation software to model the human body and its tissues and organs. Select a base cube in the 3D animation software, draw the human torso, mesh the cube according to the human body proportions, select the cube, and choose to convert it to "editable polygon". By adding auxiliary lines, according to the structural characteristics of the human body, combined with the front view and side view, stretch or compress the selected surface to make the model lines fuller and the character more three-dimensional. Use the same method to draw a model of human tissues and organs according to biological proportions. The parameters of the human body and its tissues and organs model use the human body data of a 30-year-old adult male.

[0034] S2. Establish a dynamic implantable wireless power transmission coil model in the electromagnetic simulation system simulation environment, wherein the dynamic implantable wireless power transmission coil model includes: a transmitting coil model and a receiving coil model, wherein the transmitting coil model includes the following parameters: the number of turns of the transmitting coil is 20, the minimum radius of the transmitting coil is 3 cm, the maximum radius is 3.8 cm, the spacing between the turns of the transmitting coil is 0.04 cm, and the cross-sectional current of the transmitting coil is 1 A; the receiving coil model includes the following parameters: the number of turns of the receiving coil is 20, the minimum radius of the receiving coil is 2.5 cm, the maximum radius is 3.3 cm, the spacing between the turns of the receiving coil is 0.04 cm, and the cross-sectional current of the receiving coil is 1 A;

[0035] Combine the transmitting coil model and the receiving coil model into a simulation file. In the xyz space rectangular coordinate system, set the distance between the transmitting coil model and the receiving coil model along the z-axis direction to d, the distance d is 5 cm, and set the displacement angle θ between the transmitting coil and the receiving coil.

[0036] S3, importing the human body and its tissue and organ models in step S1 into the electromagnetic simulation system simulation software.

[0037] S4, setting the displacement angle θ of the dynamic implantable wireless power transmission model to 0°, and placing the dynamic implantable wireless power transmission model with a displacement angle of 0° at different positions of the human body and its tissue and organ models, such as Figure 3 , respectively placed at the wrist joint, elbow joint, knee joint and ankle joint, to explore the electromagnetic radiation of the dynamic implantable wireless power transmission coil to the human body in different positions but with the same motion form, and to obtain the current density J of various tissues, organs and parts of the human body. rms According to the following formula (1) and formula (2), the value of specific absorption rate SAR is calculated. Figure 6 ,

[0038]

[0039]

[0040] Among them, σ is the magnetic permeability of human tissues and organs, ρ is the density of human tissues and organs, J rms is the effective value of current density, E rms It is the effective value of the field strength in the human tissue and organ area;

[0041] S5, placing the transmission coil models at different displacement angles θ established in step S2 at the same position of the human body model, such as Figure 3 The displacement angle θ is taken as 0°, 30°, 60°, and 90°. The electromagnetic radiation of the dynamic implantable wireless power transmission coil to the human body under the same position but different motion forms is explored, and the current density J of various tissues, organs, and parts of the human body is obtained. rms According to formula (1) and formula (2), the value of specific absorption rate SAR is calculated, see Figure 5 ;

[0042] S6. According to the current density J obtained in step S4 and step S5 rms And specific absorption rate SAR value, to evaluate the electromagnetic safety of dynamic implantable wireless power transmission system to the human body.

[0043] In the original national standard "Electromagnetic Radiation Protection Regulations", the average SAR value in occupational exposure environments is stipulated to be 0.1W / kg, and the average SAR value in public exposure environments is stipulated to be 0.02W / kg. However, since this standard has been abolished but there is no new relevant standard value, manufacturers and laboratories in this industry still recognize and use the above two standard values ​​for comparison.

[0044] Figure 5 and Figure 6 In the figure, the straight line of SAR=0.1W / kg represents the comparison value in the occupational exposure environment, and the straight line of SAR=0.02W / kg represents the comparison value in the public exposure environment.

[0045] like Figure 5 By comparing the simulated SAR value with the comparison value, it is found that the simulated SAR values ​​under different displacement angles θ are all below the comparison value, indicating that the electromagnetic radiation of the dynamic implantable wireless power transmission system to the human body in step S5 is within a safe range.

[0046] like Figure 6 By comparing the simulated SAR value with the comparison value, it is found that when the dynamic implantable wireless power transmission model is placed at different positions of the human body and its tissue and organ model, the simulated SAR values ​​are all below the comparison value, indicating that the electromagnetic radiation of the dynamic implantable wireless power transmission system to the human body in step S4 is within a safe range.

[0047] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Those familiar with the technology may modify or improve the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A method for evaluating the electromagnetic safety of a dynamic implantable wireless power transmission system on a human body, characterized in that: The following steps are involved: S1. Establish a model of the human body and its tissues and organs; S2. Establishing a dynamic implantable wireless power transmission coil model in a simulation environment of an electromagnetic simulation system, wherein the dynamic implantable wireless power transmission coil model includes: a transmitting coil model and a receiving coil model, and establishing a dynamic implantable wireless power transmission coil model under different displacement angles θ; S3, importing the human body and its tissue and organ models in step S1 into the electromagnetic simulation system simulation software; S4, placing the dynamic implantable wireless power transmission model under the same displacement angle θ established in step S2 at different positions of the human body and its tissue and organ model, exploring the electromagnetic radiation of the dynamic implantable wireless power transmission coil to the human body at different positions of the human body but under the same motion form, and obtaining the current density J of each tissue, organ and part of the human body rms , according to the following formula (1) and formula (2), calculate the value of specific absorption rate SAR, Among them, σ is the magnetic permeability of human tissues and organs, ρ is the density of human tissues and organs, J rms is the effective value of current density, E rms It is the effective value of the field strength in the human tissue and organ area; S5. Place the transmission coil model under different displacement angles θ established in step S2 at the same position of the human body model, explore the electromagnetic radiation of the dynamic implantable wireless power transmission coil to the human body under the same position of the human body but different motion forms, and obtain the current density J of various tissues, organs and parts of the human body. rms , according to formula (1) and formula (2), calculate the value of specific absorption rate SAR; S6. The current density J obtained in step S4 and step S5 rms and specific absorption rate (SAR) values ​​to conduct electromagnetic safety assessment of dynamic implantable wireless power transmission systems on the human body; In step S2, the method for establishing a dynamic implantable wireless power transmission coil model under different displacement angles θ is as follows: combining the transmitting coil model and the receiving coil model into a simulation file, setting the distance between the transmitting coil model and the receiving coil model along the z-axis direction to d in the xyz space rectangular coordinate system, and setting the displacement angle θ between the transmitting coil and the receiving coil.

2. The method for evaluating the electromagnetic safety of a dynamic implantable wireless power transmission system to a human body according to claim 1, characterized in that: In step S1, a human body and its tissues and organs are modeled using three-dimensional animation software.

3. The method for evaluating the electromagnetic safety of a dynamic implantable wireless power transmission system to a human body according to claim 1, characterized in that: The transmitting coil model includes the following parameters: the number of transmitting coil turns, the transmitting coil radius, the transmitting coil turn spacing, and the transmitting coil cross-sectional current; the receiving coil model includes the following parameters: the number of receiving coil turns, the receiving coil radius, the receiving coil turn spacing, and the receiving coil cross-sectional current.

4. The method for evaluating the electromagnetic safety of a dynamic implantable wireless power transmission system to a human body according to claim 1, characterized in that: In step S5, the displacement angle θ between the transmitting coil and the receiving coil is set to 0°, 30°, 60°, and 90°.

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