Time interference electrical stimulation stability regulation and control method and system based on wireless power transmission

Abstract

The invention discloses a time interference electrical stimulation stability regulation and control method and system based on wireless power transmission, belongs to the technical field of nerve electrical stimulation, and aims to solve the problems that the posture of a patient changes and the quality of envelope current induced on an electrode wrapping nerves is reduced in the using process of an existing time interference electrical stimulation technology. The method comprises the following steps of: detecting and adjusting a current ratio on transmitting coils on two sides in real time by utilizing an incidence relation among an effective value of current on an inversion side of a coil circuit on two sides, mutual inductance between the two transmitting coils and a receiving electrode and relative positions of the transmitting coils and the receiving electrode; the purpose that the electrode wrapping the nerve is located in a high-quality superimposed field for a long time and can induce stable envelope current is achieved. The beneficial effects are that before electrical stimulation starts, the electrode wrapping the nerve is arranged between the two parallel transmitting coils so that the relative position between the coils can be automatically identified and the corresponding current ratio of the coils can be adjusted, and the operation is simple; when the posture of the patient changes, high-quality envelope can be stably generated on the receiving electrode all the time.

Description

Technical Field

[0001] The present invention belongs to the technical field of neural electrical stimulation, and in particular relates to a method and system for regulating the stability of time-interference electrical stimulation based on wireless power transmission. Background Art

[0002] As the aging of the Chinese population intensifies, the incidence of neurological diseases continues to rise. Neuromodulation technology has attracted widespread attention due to its special regulation methods.

[0003] As a type of neuromodulation technology, neuroelectrical stimulation is divided into two forms: invasive and non-invasive, depending on whether it is necessary to implant stimulating electrodes. Non-invasive neuroelectrical stimulation is low-cost, but there is a lack of consistent guidelines for optimal stimulation doses and parameter control. Invasive neuroelectrical stimulation mainly consists of three parts: stimulation electrodes, extension wires, and programmable pulse generators for generating different frequencies and intensities. Pulse generators are usually battery-powered, and the battery life of medical implants is about 10 years, requiring surgical replacement. Wireless rechargeable batteries have a lifespan of about 20 years, but there is also a need for replacement and the risk of battery leakage, which increases the patient's surgical risk, economic burden, and psychological pressure.

[0004] Time-interference electrical stimulation only requires two or more external electrodes, and implantable wireless charging consists only of external power supply and in-vivo reception. Combining time-interference electrical stimulation with implantable wireless charging can achieve wireless charging and neural regulation simultaneously while replacing the pulse generator and extension cord, greatly reducing the surgical risk for patients.

[0005] However, the key point of applying wireless charging technology to time-interference electrical stimulation is that time-interference electrical stimulation uses two high-frequency currents with a small frequency difference to superimpose a low-frequency envelope induced electric field at the stimulation target, replacing traditional pulse electrical stimulation. The peak-to-peak value of the low-frequency envelope induced electric field is greater than the nerve response threshold, and the neuron responds. During the stimulation process, changes in the patient's posture will cause the spatial position of the electrode wrapped around the nerve to change. The envelope induced electric field superimposed on the electrode cannot meet the target area nerve response threshold requirements, and the stimulation effect becomes poor, which seriously affects the stability of the nerve electrical stimulation device. Summary of the invention

[0006] In view of this, the present invention aims to propose a method and system for controlling stability of time-interferometric electrical stimulation based on wireless power transmission, so as to at least solve one of the problems in the background technology.

[0007] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0008] A method for regulating stability of time-interference electrical stimulation based on wireless power transmission comprises the following steps:

[0009] S1, implanting wrapped electrodes and compensation capacitors;

[0010] S2. Place two coils in parallel on both sides of the electrode, and adjust the appropriate position of the transmitting coil so that the transmission efficiency and output power of the system reach the predetermined values, so that the transmission efficiency and output power are at a high level;

[0011] S3, connect the power supply of the coils on both sides, and pass current with the same amplitude and frequency difference of tens or hundreds of hertz;

[0012] S4, collecting the current on the inverter side of the coil circuit on both sides and inputting it into the control module;

[0013] S5, the control module processes the data to obtain the relative positions of the two transmitting coils and the electrodes;

[0014] S6. The control module adjusts the current ratio on the transmitting coil through the relationship between the relative position between the coils and the current ratio on both sides, so as to generate a high-quality envelope current on the electrode.

[0015] Furthermore, the high-quality envelope current is a current envelope when the envelope modulation depth reaches a neuron response threshold within a difference frequency period.

[0016] Furthermore, S11, the implanted electrode is a spiral electrode, which is small in size and wraps the nerve tightly, so as to achieve the dual functions of wireless power reception and electrical stimulation nerve regulation at the same time;

[0017] S12. The two transmitting coils are both spiral-shaped and placed in parallel.

[0018] Furthermore, the spacing distance between the two transmitting coils is 1 times the diameter of the transmitting coil.

[0019] Furthermore, the step of obtaining the relative positions of the two transmitting coils and the electrodes includes:

[0020] The positional relationship between coils is calculated by detecting the effective value of the current.

[0021] Furthermore, the step of calculating the positional relationship between coils by detecting the effective value of the current includes:

[0022] S31. Write the KVL loop equation for the circuit as follows:

[0023]

[0024] In the formula, and are the output voltage and current of inverter i, , and are the resonant compensation inductor, parallel compensation capacitor and series compensation capacitor in the i-th LCC resonant compensation network, respectively. and are the self-inductance and equivalent series resistance of the transmitting coil i, and are the self-inductance and equivalent series resistance of the receiving electrode, For load, is the mutual inductance between the transmitting coil i and the receiving coil, is the operating angular frequency, is the excitation current of coil i, is the receiving current of the receiving electrode, is the parallel compensation capacitor of the receiving electrode;

[0025] The relationship between the mutual inductance and the effective value of the inverter side current is calculated as:

[0026]

[0027] in:

[0028]

[0029] S32. Calculate the real-time mutual inductance between the transmitting coil and the receiving electrode according to the real-time detected current effective value.

[0030] Furthermore, the step of obtaining the relative position relationship between the two transmitting coils and the electrode also includes:

[0031] S33, the time interference electrical stimulation system consists of two transmitting coils and one receiving electrode, and the radius of the two transmitting coils is r 1 , the number of turns is N 1 , the two sets of mutual inductance formulas between the two transmitting coils and the receiving electrodes are:

[0032]

[0033] in:

[0034]

[0035] Where N 1 、N 2 are the turns of the transmitting coil and the receiving coil, μ 0 is the vacuum permeability, r 1 、r 2 are the radii of the transmitting coil and the receiving coil respectively, is the angle between the point on the transmitting coil and the coordinate, is the angle between the point on the receiving coil and the coordinate, , are the transmitting coil and receiving coil microelement respectively, is the offset angle between the transmitting coil and the receiving coil, h i is the axial distance between the transmitting coil i and the receiving coil, t i is the radial distance between the transmitting coil i and the receiving coil;

[0036] S34, when the shapes and sizes of the transmitting coil and the receiving electrode are determined and the electrode angle offset is not considered, the sum of the axial distances is a certain value, and the radial distances are equal. The empirical formula method is used to obtain the expressions between the radial distance and the axial distance and the two mutual inductance values ​​by plotting the discrete points of the formula and then fitting them;

[0037] S35, detecting the current to obtain two mutual inductance values, and then obtaining the relative position relationship between the receiving electrode and the two transmitting coils according to the two mutual inductance values.

[0038] Furthermore, the step of regulating the current ratio includes:

[0039] S41, different current ratios induce different envelope current qualities on the receiving electrode; by changing the current ratio, the receiving electrode can induce high-quality envelope current at different positions;

[0040] S42, dividing the areas inside the two transmitting coils into discrete areas, and recording the current ratios corresponding to the electrodes in each area in turn;

[0041] S43. After the system is running, the corresponding current ratio is directly queried according to the calculated position coordinates to perform current control.

[0042] Furthermore, the present invention discloses a time-interference electrical stimulation stability control system based on wireless power transmission, comprising:

[0043] Electrode module: used for power reception and neural regulation, consisting of receiving electrodes and compensation capacitors;

[0044] Transmitter module: used for power transmission and generation of stimulation envelope, including two coils with the same parameters and coil compensation circuit; currents with the same amplitude and frequency difference of tens or hundreds of hertz are passed through the two coils to induce envelope currents for nerve regulation on the electrodes;

[0045] Control module: used to collect current signals in the circuit and control the current frequency and current amplitude ratio on the two transmitting coils. It consists of a host computer, a processor, a signal acquisition circuit, and an ADC digital-to-analog conversion circuit. The processor processes the data to obtain the relative position of the two transmitting coils and the electrodes, and adjusts the current on the transmitting coil based on the relative position of the two transmitting coils and the electrodes obtained above, so that high-quality envelope current is induced on the electrodes in real time.

[0046] Power module: used to convert industrial frequency current into current with controllable frequency and amplitude, consisting of a DC source plus an inverter bridge.

[0047] Compared with the prior art, the method and system for controlling stability of time-interference electrical stimulation based on wireless power transmission described in the present invention have the following beneficial effects:

[0048] (1) The present invention discloses a method and system for controlling the stability of time-interference electrical stimulation based on wireless power transmission. Before the start of electrical stimulation, the wrapped nerve electrode is placed between two parallel transmitting coils. After the system is started, the control module automatically identifies the relative position between the transmitting coil and the receiving electrode by processing the collected current data, and adjusts the current ratio of the two transmitting coils to induce a high-quality envelope current on the receiving electrode.

[0049] (2) The method and system for controlling the stability of time-interference electrical stimulation based on wireless power transmission described in the present invention can always generate a high-quality envelope on the receiving electrode when the patient's posture changes, that is, when the position of the receiving electrode changes within the area of ​​the two transmitting coils, thereby providing the patient with better comfort without affecting the patient's conditioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0051] Figure 1 A schematic flow chart of a method for controlling stability of time-interference electrical stimulation based on wireless power transmission provided by an embodiment of the present invention;

[0052] Figure 2 A schematic diagram of the structure of a time-interference electrical stimulation stability system based on wireless power transmission provided by an embodiment of the present invention;

[0053] Figure 3 A circuit topology diagram of a time interference electrical stimulation stability control method based on wireless power transmission provided by an embodiment of the present invention;

[0054] Figure 4 A graph of changes in the position of receiving electrodes in a method for controlling the stability of time-interference electrical stimulation based on wireless power transmission provided by an embodiment of the present invention;

[0055] Figure 5 An envelope effect diagram of a method for controlling stability of time-interference electrical stimulation based on wireless power transmission provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0056] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0057] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0058] A method for regulating stability of time-interference electrical stimulation based on wireless power transmission comprises the following steps:

[0059] Implantation of wrapped electrodes and compensation capacitors;

[0060] Two coils are placed in parallel on both sides of the electrode, and the transmitting coil is adjusted to a suitable position so that the transmission efficiency and output power of the system are at a higher level;

[0061] Connect the power supply of the coils on both sides, and pass current with the same amplitude and frequency difference of tens or hundreds of hertz;

[0062] Collect the current on the inverter side of the coil circuit on both sides and input it into the control module;

[0063] The control module processes the data to obtain the relative positions of the two transmitting coils and the electrodes;

[0064] The principle of obtaining the position relationship between the two transmitting coils and the electrode from the current data is described in the specific embodiment.

[0065] The control module adjusts the current on the transmitting coil by the relationship between the relative position between the coils and the current ratio on both sides, so that a high-quality current envelope is generated on the electrode;

[0066] The high-quality current envelope is explained as follows: within a difference frequency period, the difference between the peak value at the maximum and the peak value at the minimum of the envelope waveform is the envelope modulation depth. When the envelope modulation depth reaches the neuron response threshold, the current envelope is called a high-quality current envelope. Figure 5 , M 1 / 2 and M 2 The current envelope when the difference of / 2 reaches the neuron response threshold is called a high-quality current envelope.

[0067] The system operates normally, and the control module collects current information in real time and makes feedback, so that the electrode always generates high-quality envelope current when moving in the area of ​​the two transmitting coils.

[0068] The present invention provides a method for regulating stability of time-interference electrical stimulation based on wireless power transmission, comprising the following steps:

[0069] S1, implanting wrapped electrodes and compensation capacitors;

[0070] Furthermore, the implantable wrapped electrode is a spiral electrode, which is small in size and tightly wraps the nerves. The electrode has the dual functions of wireless power reception and electrical stimulation of nerve regulation.

[0071] S2. Place two coils in parallel on both sides of the electrode, and adjust the appropriate position of the transmitting coil so that the transmission efficiency and output power of the system reach the predetermined values, so that the transmission efficiency and output power are at a high level;

[0072] In the embodiment, two transmitting coils are placed in parallel on both sides of the electrode, both are spiral-shaped and placed in parallel to generate a uniform magnetic field between the two coils. Since the transmission efficiency and output power of the system in the magnetic coupling resonant wireless power transmission first increase and then decrease as the distance between the transmitting coil and the receiving coil increases from near to far, it is generally believed that when the distance between the transmitting coil and the receiving coil is 1-2 times the coil radius, the transmission efficiency and output power of the system are at a higher level, so the distance between the two transmitting coils is selected to be 1 times the diameter of the transmitting coil.

[0073] S3, connect the power supply of the coils on both sides, and pass current with the same amplitude and frequency difference of tens or hundreds of hertz;

[0074] In the embodiment, the current frequency on one side of the coil is the system operating frequency and the base frequency of the envelope current, and the current frequency on the other side of the coil is the system operating frequency plus tens or hundreds of hertz, and the frequencies on both sides of the system always differ by tens or hundreds of hertz to ensure that the envelope current frequency on the receiving electrode is always tens or hundreds of hertz. The current amplitude is greater than the minimum value of the excitation threshold of the electrically stimulated neuron and less than the maximum safety threshold of the electrical stimulation.

[0075] S4, collecting the current on the inverter side of the coil circuit on both sides and inputting it into the control module;

[0076] Furthermore, the current described in step S4 is the effective value of the current.

[0077] S5, the control module processes the data to obtain the relative positions of the two transmitting coils and the electrodes;

[0078] The relative positions of the two transmitting coils and the electrode are related to the effective value of the detected current, that is, the positional relationship between the coils can be deduced through the effective value.

[0079] S6. The control module adjusts the current on the transmitting coil through the relationship between the relative position between the coils and the current ratio on both sides, so that a high-quality envelope current is generated on the electrode.

[0080] Furthermore, the current ratio is the ratio of the currents flowing through the transmitting coils on both sides, and different current ratios induce different envelope current qualities on the receiving electrode. Therefore, by changing the current ratio in real time, the receiving electrode can induce high-quality envelope currents at different positions.

[0081] Combine the following Figure 2 The present invention provides a time interference electrical stimulation stability control system based on wireless power transmission, comprising:

[0082] Electrode module: used for electrical energy reception and neural regulation.

[0083] Transmitter module: used for power transmission and generation of stimulus envelope.

[0084] Control module: used to collect the current signal in the circuit and control the current frequency and current amplitude ratio on the two transmitting coils.

[0085] Power module: used to convert industrial frequency current into current with controllable frequency and amplitude.

[0086] The electrode module is composed of a receiving electrode and a compensation capacitor, with fewer components, which is conducive to reducing the implant volume of the device.

[0087] The transmitting module includes two coils with the same parameters and a coil compensation circuit.

[0088] The power supply module consists of a DC source and an inverter bridge, which is easy to control.

[0089] The control module consists of a host computer, a processor, a signal acquisition circuit, and an ADC digital-to-analog conversion circuit.

[0090] In the embodiment, first, the position of the receiving electrode is determined, and the position of the transmitting coil is roughly adjusted so that the transmission efficiency and output power of the system reach predetermined values, so that the transmission efficiency and output power are at a higher level. Since the time interference electrical stimulation neurons have no response to currents with a base frequency above 10kHz, and the higher the frequency of magnetically coupled resonant wireless power transmission, the higher the transmission efficiency, the present invention selects a base frequency of 10kHz for subsequent description, and uses this frequency matching compensation circuit. Then, the frequency of the inverter circuit is adjusted by the control module, and currents with frequencies of 10kHz and 10k+10Hz are generated on the transmitting coil respectively. The following equation is satisfied during system operation:

[0091]

[0092] The signal acquisition circuit collects the current on the inverter side through the Hall current transformer and sends it to the control module for processing in real time.

[0093] By writing the KVL loop equation for the circuit as follows, the circuit topology diagram is as follows Figure 3

[0094]

[0095] In the formula, and are the output voltage and current of inverter i, , and are the resonant compensation inductor, parallel compensation capacitor and series compensation capacitor in the i-th LCC resonant compensation network, respectively. and are the self-inductance and equivalent series resistance of the transmitting coil i, and are the self-inductance and equivalent series resistance of the receiving electrode, For load, is the mutual inductance between the transmitting coil i and the receiving coil, is the operating angular frequency, is the excitation current of coil i, is the receiving current of the receiving electrode, is the parallel compensation capacitor of the receiving electrode.

[0096] The formula for calculating mutual inductance and inverter side current is as follows

[0097]

[0098] in

[0099]

[0100] It can be seen from the formula that when the parameters such as coil and topology in the system are determined, the mutual inductance between the transmitting coil and the receiving electrode is only related to the effective value of the inverter side current. Therefore, the real-time mutual inductance value of the coil is calculated by detecting the effective value of the current in real time.

[0101] In wireless power transmission, the relative position of the transmitting coil and the receiving coil and the mutual inductance between the coils are expressed as follows:

[0102]

[0103]

[0104] Where M is the mutual inductance between the transmitting coil and the receiving coil, N 1 、N 2 are the turns of the transmitting coil and the receiving coil, μ 0 is the vacuum permeability, r 1 、r 2 are the radii of the transmitting coil and the receiving coil respectively, is the angle between the point on the transmitting coil and the coordinate, is the angle between the point on the receiving coil and the coordinate, , are the transmitting coil and receiving coil microelement respectively, is the offset angle between the transmitting coil and the receiving coil, h is the axial distance between the transmitting coil and the receiving coil, and t is the radial distance between the transmitting coil and the receiving coil. The position change of the receiving electrode relative to the transmitting coil is as follows: Figure 4 shown.

[0105] It should be noted that the present invention only addresses the case where the receiving electrode moves parallel to the transmitting coil, and does not consider the case where the receiving electrode and the transmitting coil are angularly deflected.

[0106] Since the time interference electrical stimulation system in the present invention is composed of two transmitting coils and one receiving electrode, and the radius of the two transmitting coils is r 1 , the number of turns is N 1 , so the two sets of mutual inductance formulas between the two transmitting coils and the receiving electrodes are as follows

[0107]

[0108] in

[0109]

[0110] In the formula, h i is the axial distance between the transmitting coil i and the receiving coil, t i is the radial distance between the transmitting coil i and the receiving coil.

[0111] According to the above formula, after the shape and size of the transmitting coil and the receiving electrode are determined, the sum of their axial distances is a certain value, and the radial distances are equal.

[0112]

[0113] The above formula is only a set of equations between two mutual inductance values, a radial distance, and an axial distance. Therefore, expressions between the radial distance and the axial distance and the two mutual inductance values ​​are solved according to the formula.

[0114] Since the system of equations involves double integrals, the calculation is complicated. The formula is discretized and plotted, and then fitted to obtain a simpler formula to replace the original complex formula.

[0115] Now, taking the two transmitting coils with a radius of 5 cm, the receiving electrode with a radius of 2 cm, 10 turns and a distance of 10 cm between the two transmitting coils as an example, the simplified equations are as follows:

[0116]

[0117] Solve the system of equations and get

[0118]

[0119] The electrode positions are solved based on the obtained real-time mutual inductance between the coils.

[0120] Different current ratios induce different envelope current qualities on the receiving electrode. Changing the current ratio can make the receiving electrode induce high-quality envelope currents at different positions. Therefore, before the implementation, the areas inside the two transmitting coils are divided into discrete areas, and the current ratios corresponding to the electrodes in each area are recorded in turn. After the system is running, the corresponding current ratio is directly queried according to the calculated position coordinates to perform current control, which greatly saves control time.

[0121] The present invention provides a method for controlling the stability of time-interference electrical stimulation based on wireless power transmission. The method calculates the relative position between the receiving electrode and the two transmitting coils by detecting the effective value of the inverter-side current of the coil circuit on both sides in real time. Then, the corresponding current ratio is adjusted according to the relationship between the coil position and the current ratio obtained in advance, so that a current with a high-quality envelope waveform is always induced on the receiving electrode.

[0122] Those of ordinary skill in the art will appreciate that the units and method steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0123] In the several embodiments provided in the present application, it should be understood that the disclosed methods and systems can be implemented in other ways. For example, the division of the units described above is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. The above-mentioned units may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiments of the present invention.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

[0125] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling the stability of electrical stimulation based on time interference of wireless power transmission, characterized in that: The steps include: S1, implanting wrapped electrodes and compensation capacitors; S2. Place two coils in parallel on both sides of the electrode, and adjust the appropriate position of the transmitting coil so that the transmission efficiency and output power of the system reach the predetermined values, so that the transmission efficiency and output power are at a high level; S3, connect the power supply of the coils on both sides, and pass current with the same amplitude and frequency difference of tens or hundreds of hertz; S4, collecting the current on the inverter side of the coil circuit on both sides and inputting it into the control module; S5, the control module processes the data to obtain the relative positions of the two transmitting coils and the electrodes; S6. The control module adjusts the current ratio on the transmitting coil through the relationship between the relative position between the coils and the current ratio on both sides, so as to generate a high-quality envelope current on the electrode.

2. A method for controlling stability of time-interference electrical stimulation based on wireless power transmission according to claim 1, characterized in that: The high-quality envelope current is the current envelope when the envelope modulation depth reaches the neuron response threshold within one difference frequency cycle.

3. The method for controlling stability of time-interference electrical stimulation based on wireless power transmission according to claim 1, characterized in that: S11. The implanted electrode is a spiral electrode, which is small in size and tightly wraps the nerve, so as to achieve the dual functions of wireless power reception and electrical stimulation nerve regulation at the same time; S12. The two transmitting coils are both spiral-shaped and placed in parallel.

4. The method for controlling stability of time-interference electrical stimulation based on wireless power transmission according to claim 1, characterized in that: The distance between the two transmitting coils is 1 times the diameter of the transmitting coil.

5. The method for controlling stability of time-interference electrical stimulation based on wireless power transmission according to claim 1, characterized in that: The step of obtaining the relative positions of the two transmitting coils and the electrodes comprises: The positional relationship between coils is calculated by detecting the effective value of the current.

6. The method for controlling stability of time-interference electrical stimulation based on wireless power transmission according to claim 1, characterized in that: The step of calculating the positional relationship between coils by detecting the effective value of the current comprises: S31. Write the KVL loop equation for the circuit as follows: ； In the formula, and are the output voltage and current of inverter i, respectively. , and are the resonant compensation inductor, parallel compensation capacitor and series compensation capacitor in the i-th LCC resonant compensation network, respectively. and are the self-inductance and equivalent series resistance of the transmitting coil i, and are the self-inductance and equivalent series resistance of the receiving electrode, For load, is the mutual inductance between the transmitting coil i and the receiving coil, is the operating angular frequency, is the excitation current of coil i, is the receiving current of the receiving electrode, is the parallel compensation capacitor of the receiving electrode; The relationship between the mutual inductance and the effective value of the inverter side current is calculated as: ； in: ； S32. Calculate the real-time mutual inductance between the transmitting coil and the receiving electrode according to the real-time detected current effective value.

7. The method for controlling stability of time-interference electrical stimulation based on wireless power transmission according to claim 1, characterized in that: The step of obtaining the relative position relationship between the two transmitting coils and the electrode also includes: S33. The time-interference electrical stimulation system consists of two transmitting coils and one receiving electrode, and the radius of the two transmitting coils is r1, the number of turns is N1, and the two sets of mutual inductance formulas between the two transmitting coils and the receiving electrode are: ； in: ； Where N1 and N2 are the turns of the transmitting coil and the receiving coil, μ0 is the vacuum magnetic permeability, r1 and r2 are the radii of the transmitting coil and the receiving coil, respectively. is the angle between the point on the transmitting coil and the coordinate, is the angle between the point on the receiving coil and the coordinate, , are the transmitting coil and receiving coil microelement respectively, is the offset angle between the transmitting coil and the receiving coil, h i is the axial distance between the transmitting coil i and the receiving coil, t i is the radial distance between the transmitting coil i and the receiving coil; S34, when the shapes and sizes of the transmitting coil and the receiving electrode are determined and the electrode angle offset is not considered, the sum of the axial distances is a certain value, and the radial distances are equal. The empirical formula method is used to obtain the expressions between the radial distance and the axial distance and the two mutual inductance values ​​by plotting the discrete points of the formula and then fitting them; S35, detecting the current to obtain two mutual inductance values, and then obtaining the relative position relationship between the receiving electrode and the two transmitting coils according to the two mutual inductance values.

8. The method for controlling the stability of time-interference electrical stimulation based on wireless power transmission according to claim 1, characterized in that: The steps for regulating the current ratio include: S41, different current ratios induce different envelope current qualities on the receiving electrode; by changing the current ratio, the receiving electrode can induce high-quality envelope current at different positions; S42, dividing the areas inside the two transmitting coils into discrete areas, and recording the current ratios corresponding to the electrodes in each area in turn; S43. After the system is running, the corresponding current ratio is directly queried according to the calculated position coordinates to perform current control.

9. A time-interference electrical stimulation stability control system based on wireless power transmission, based on the method described in any one of claims 1 to 8, characterized in that: Electrode module: used for power reception and neural regulation, consisting of receiving electrodes and compensation capacitors; Transmitter module: used for power transmission and generation of stimulation envelope, including two coils with the same parameters and coil compensation circuit; currents with the same amplitude and frequency difference of tens or hundreds of hertz are passed through the two coils to induce envelope currents for nerve regulation on the electrodes; Control module: used to collect current signals in the circuit and control the current frequency and current amplitude ratio on the two transmitting coils. It consists of a host computer, a processor, a signal acquisition circuit, and an ADC digital-to-analog conversion circuit. The processor obtains the relative positions of the two transmitting coils and the electrodes by processing data, and adjusts the current on the transmitting coil based on the relative positions of the two transmitting coils and the electrodes obtained above, so that high-quality envelope current is induced on the electrodes in real time. Power module: used to convert industrial frequency current into current with controllable frequency and amplitude, consisting of a DC source plus an inverter bridge.

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