Controllable electromagnetic excitation system and method based on combined three-dimensional coil array

Abstract

The invention belongs to the technical field of geophysical electromagnetic method exploration, and provides a controllable electromagnetic excitation system and method based on a combined three-dimensional coil array, a central control system calculates control parameters of each three-dimensional coil basic unit according to electromagnetic excitation demand parameters and the size and the shape of the three-dimensional coil array, and the control parameters of each three-dimensional coil basic unit are calculated according to the electromagnetic excitation demand parameters and the size and the shape of the three-dimensional coil array; the corresponding three-dimensional coil basic units adjust emission current according to the control parameters; the power supply distribution system determines the power supply demand of each distributed power supply module according to the control parameters calculated by the central control system, and provides a stable power supply for each three-dimensional coil basic unit; in response to a user configuration request, the control parameters of the central control system are adjusted according to the configuration parameters in the configuration request, and then the emission current parameters of the three-dimensional coil basic units are adjusted. According to actual needs, through physical combination of the three-dimensional coil basic units in space and regulation and control of emission current amplitude, phase and frequency, accurate regulation and control of an electromagnetic field are realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of geophysical electromagnetic exploration, and in particular relates to a controllable electromagnetic excitation system and method based on a combined three-dimensional coil array. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Geophysical electromagnetic exploration generally utilizes the differences in conductivity and dielectric properties of media such as rocks and ore bodies, analyzes the received electromagnetic response signals using the principle of electromagnetic induction, and inverts the underground electrical structure. Based on the source type, electromagnetic detection methods can be divided into natural source (passive) electromagnetic methods, artificial source (active) electromagnetic methods, and mixed source electromagnetic methods that combine controllable and natural sources. Artificial source electromagnetic methods offer advantages such as flexibility and controllability, a high signal-to-noise ratio, and strong anti-interference capabilities, making them widely used in mineral exploration, rail transit construction, and engineering geological surveys.

[0004] At present, the research of domestic and foreign scholars on artificial source electromagnetic excitation devices mainly focuses on the following aspects: 1) By developing a higher-power power amplifier, the emission current can be increased to achieve high-energy excitation; 2) Resonate and match the transmitting coil to increase the transmitting current; 3) Use distributed transmitting coil arrays such as conical coil arrays to focus the magnetic field and increase the energy of the transmitting magnetic field.

[0005] However, due to the high high-frequency inductance of the coil, simply increasing the voltage across the transmitting coil cannot effectively increase the transmitting current, and thus cannot effectively increase the energy of the excited electromagnetic field, nor can it adjust the energy of the excited electromagnetic field according to the needs of the detection target.

[0006] However, when using transmitting coil resonant matching technology, the available frequency points are limited and the switching channels are complicated, which affects the detection efficiency.

[0007] In addition, the use of conical coil arrays to focus the magnetic field has limited effect, and the direction of the magnetic field cannot be changed without moving the physical device, making omnidirectional detection impossible in a limited space.

[0008] In summary, existing technologies have problems such as limited excitation energy, poor controllability, and low recognition, making it difficult to support the detection of deep and long-distance geological environments. Summary of the Invention

[0009] In order to solve the above problems, the present invention proposes a controllable electromagnetic excitation system and method based on a combined three-dimensional coil array. According to actual needs, the present invention utilizes multiple three-dimensional coil basic units to freely combine into various shapes such as spheres, cubes, and cones. Through the physical combination of the three-dimensional coil basic units in space and the regulation of the emission current amplitude, phase and frequency, the present invention achieves precise control of the excitation electromagnetic field.

[0010] According to some embodiments, the present invention adopts the following technical solutions: A controllable electromagnetic excitation system based on a combined three-dimensional coil array includes a three-dimensional coil array, a central control system, a communication system, and a power distribution system, wherein: The three-dimensional coil array includes a plurality of three-dimensional coil basic units, each of which is arranged in sequence to form a three-dimensional structure. Each three-dimensional coil basic unit includes three groups of orthogonal Helmholtz coils to form a cubic structure. The three groups of orthogonal Helmholtz coils are used to provide three orthogonal magnetic field components, and the control parameters of the transmission current of each Helmholtz coil are adjustable. The central control system is used to calculate the control parameters of each three-dimensional coil basic unit based on the required parameters of electromagnetic excitation and the size and shape of the three-dimensional coil array, and send the calculated control parameters to the corresponding three-dimensional coil basic unit through the communication system to change the control parameters; The power distribution system includes a power distributor and multiple distributed power modules. The power distributor determines the power supply requirements of each distributed power module based on the control parameters calculated by the central control system. Each distributed power module independently supplies power to several three-dimensional coil basic units under the control of the power distributor.

[0011] As an optional implementation, each three-dimensional coil basic unit further includes a transmission excitation module, a transmission current waveform recording module, a control module, a communication module and a power supply module, wherein the transmission excitation module is used to achieve transmission waveform frequency, phase and amplitude modulation; The transmitting current waveform recording module is used to detect the amplitude, frequency and phase of the transmitting current in the Helmholtz coil and transmit them to the control module; The control module is used to control the transmitting excitation module to adjust the amplitude, frequency and phase of the transmitting current of the Helmholtz coil according to the calculated control parameters, and receive the detection data fed back by the transmitting current waveform recording module to perform automatic adjustment; The communication module is used to provide a communication path for the control module and other modules; The power supply module is used to provide a DC voltage to the Helmholtz coil.

[0012] As a further limited embodiment, the transmitting excitation module includes an impedance matching circuit, a full-bridge inverter circuit, a drive circuit and a signal isolation circuit, wherein the impedance matching circuit is used to perform impedance matching with the Helmholtz coil; The full-bridge inverter circuit is used to generate a transmission waveform and is controlled by a control module using pulse width modulation technology. The output voltage and waveform are controlled by adjusting the conduction pulse width of the switching devices in the full-bridge inverter circuit. The driving circuit is used to amplify the control signal of the control module to drive the full-bridge inverter to work; The signal isolation circuit is used to isolate the connection between the drive circuit and the full-bridge inverter circuit.

[0013] As an optional implementation, the communication system adopts a hierarchical structure, wherein the central control system is a master node for global scheduling and coordinating the working modes of all three-dimensional coil basic units. The control module of each three-dimensional coil basic unit is a slave node. The master node sends control instructions to each slave node. The slave nodes are networked and can communicate with each other.

[0014] As an optional embodiment, the intervals between adjacent three-dimensional coil basic units are within a set range.

[0015] As an optional implementation, it further includes a human-computer interaction system, which communicates with the central control system and is used to receive user configuration parameters and adjust control parameters of the central control system according to the configuration parameters.

[0016] The working method based on the above system includes the following steps: The central control system calculates the control parameters of each three-dimensional coil basic unit based on the required parameters of electromagnetic excitation and the size and shape of the three-dimensional coil array, and sends the calculated control parameters to the corresponding three-dimensional coil basic unit through the communication system. The corresponding three-dimensional coil basic unit adjusts the transmission current according to the control parameters. The power distribution system determines the power supply requirements of each distributed power module based on the control parameters calculated by the central control system, and provides stable power supply for each three-dimensional coil basic unit; In response to a user configuration request, the control parameters of the central control system are adjusted according to the configuration parameters in the configuration request, thereby adjusting the transmission current parameters of each three-dimensional coil basic unit.

[0017] As an optional implementation, the process of calculating the control parameters of each three-dimensional coil basic unit based on the required parameters of electromagnetic excitation and the size and shape of the three-dimensional coil array includes: controlling the magnetic induction intensity and direction at a maximum of 2*n points on a reference surface of a three-dimensional coil array composed of n three-dimensional coil basic units, setting the magnetic induction intensity and direction at 2*n points within a reasonable range while considering the mutual inductance interference between coils, and using the electromagnetic field coupling inverse solution algorithm to reversely calculate the excitation current amplitude and direction in each rectangular coil in the three-dimensional coil array to obtain the control parameters, thereby enabling the three-dimensional coil array to excite a directional electromagnetic field in space.

[0018] Furthermore, based on the required parameters of electromagnetic excitation and the size and shape of the three-dimensional coil array, the process of calculating the control parameters of each three-dimensional coil basic unit includes: based on the relationship between the magnetic field generated by the three-dimensional coil basic unit in space and the excitation current and excitation voltage, deriving that the electromagnetic field excited at a certain point in space by the three-dimensional coil array obtained by freely combining n three-dimensional coil basic units is obtained by superimposing the electromagnetic fields excited by the corresponding number of three-dimensional coil basic units: ; in, , , are the x-component, y-component, and z-component of the magnetic induction intensity generated by the n-th three-dimensional coil basic unit at this point. To ensure that the linear equations have a unique solution, the relationship matrix between the 2*n points in space and the distributed current is listed: ； Where A is the relationship matrix between 2*n points in space and the distributed current of the three-dimensional coil array. Its internal element e is derived from the magnetic field formula generated by the rectangular coil at a certain point. B is the expected magnetic field matrix, and I is the distributed current matrix. ; ; ; in, , , is the three-component magnetic induction intensity excited by the three-dimensional coil array at the nth point, is the excitation current in the nth rectangular coil; Given the magnetic induction intensity and direction of the magnetic field at 2*n points in space, find the excitation current in 6*n coils under this condition. Under the condition that the excitation current and the physical laws of the electromagnetic field are satisfied, the magnetic induction intensity and direction of the magnetic field at 2*n points can be arbitrarily set, which can realize the control of the synthetic magnetic field intensity and direction to a certain extent. After obtaining the distributed current of the three-dimensional coil array, the excitation voltage is obtained by Kirchhoff's voltage law, taking into account the mutual inductance of the coils. The current-voltage relationship is as follows: ; in, is the current flowing through the nth coil, is the voltage applied across the nth coil, is the mutual inductance between the mth coil and the nth coil, is the impedance of the nth coil circuit. When the shape, spatial position and medium in the space of the coil are determined, the mutual inductance is uniquely determined and can be measured. Its sign is determined by whether the magnetic field generated by coil m enhances the magnetic field generated by coil n.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The present invention adopts a flexible combination of three-dimensional coil arrays. According to user needs, three-dimensional coil basic units can be arbitrarily combined to form a three-dimensional coil array with variable shape. Through the electromagnetic field coupling inverse solution algorithm, a complex electromagnetic field with precise controllability can be formed in space.

[0020] The present invention utilizes an electromagnetic field coupling reverse solution algorithm to reversely solve the control parameters of each three-dimensional coil basic unit of any combination of three-dimensional coil arrays according to user-set magnetic field parameters or required magnetic field parameters.

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which constitute 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 improper limitations on the present invention.

[0023] Figure 1 is a schematic diagram of a basic unit structure of a three-dimensional coil in an embodiment; Figure 2 is a schematic diagram of a cubic three-dimensional coil array in an embodiment; Figure 3 is a schematic diagram of a spherical three-dimensional coil array in an embodiment; Figure 4 is a schematic diagram of a rectangular coil and a point P(x, y, z) in an embodiment; Figure 5FIG. 1 is a schematic diagram of an equivalent circuit model considering the mutual inductance of coils in an embodiment. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0026] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0027] In the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0028] Example 1 A controllable electromagnetic excitation system based on a combined three-dimensional coil array includes a three-dimensional coil array, a central control system, a communication system, and a power distribution system, wherein: The three-dimensional coil array includes a plurality of three-dimensional coil basic units, each of which is arranged in sequence to form a three-dimensional structure, such as Figure 1 As shown, each three-dimensional coil basic unit includes three groups of orthogonal Helmholtz coils to form a cubic structure. The three groups of orthogonal Helmholtz coils are used to provide three orthogonal magnetic field components, and the control parameters of the emission current of each Helmholtz coil are adjustable; The central control system is used to calculate the control parameters of each three-dimensional coil basic unit based on the required parameters of electromagnetic excitation and the size and shape of the three-dimensional coil array, and send the calculated control parameters to the corresponding three-dimensional coil basic unit through the communication system to change the control parameters; The power distribution system includes a power distributor and multiple distributed power modules. The power distributor determines the power supply requirements of each distributed power module based on the control parameters calculated by the central control system. Each distributed power module independently supplies power to several three-dimensional coil basic units under the control of the power distributor.

[0029] Each 3D coil unit also includes a transmitter excitation module, a transmitter current waveform recording module, a control module, a communication module, and a power supply module. Three sets of orthogonal Helmholtz coils provide three orthogonal magnetic field components, the magnitude of which is proportional to the magnitude of the transmitter current passing through the coils. Therefore, by controlling the amplitude of the transmitter current, a directional electromagnetic field can be formed in space.

[0030] The transmit excitation module is used to modulate the frequency, phase, and amplitude of the transmit waveform. It includes an impedance matching circuit, a full-bridge inverter circuit, a drive circuit, and a signal isolation circuit. The impedance matching circuit matches the impedance of the transmit coil, minimizing signal reflection and energy loss, thereby improving energy transmission efficiency.

[0031] The full-bridge inverter circuit is used to generate the emission waveform and is controlled by the control module using pulse width modulation (PWM) technology. By adjusting the conduction pulse width of the switching device, the output voltage and waveform can be precisely controlled. The control is simple and easy to implement.

[0032] Because the voltage generated by the control module is insufficient to directly drive the full-bridge inverter, a driver circuit is used to amplify this voltage to drive the full-bridge inverter. Furthermore, because the high voltage in the full-bridge inverter circuit can easily interfere with the low voltage in the control module through the driver circuit, a signal isolation circuit is required to isolate the connection between the drive signal and the switching devices of the full-bridge inverter circuit.

[0033] The transmit current waveform recording module monitors the amplitude, frequency, and phase of the transmit current in the three-dimensional coil basic unit in real time and transmits this information to the control module in real time. The control module consists of a main control unit and a power management unit. The main control unit controls the full-bridge inverter, adjusting the transmit current's amplitude, frequency, and phase, among other parameters. The module receives the information collected by the transmit current waveform recording module and automatically adjusts it through a feedback mechanism, improving system stability. The power supply module, using components such as a switching power supply, provides a stable DC voltage for the entire system.

[0034] A series of three-dimensional coil basic units can be freely combined in space to form a sphere (such as Figure 3 As shown), cube (as Figure 2 The controllable electromagnetic excitation system, composed of a series of freely combined 3D coil units, enables more refined magnetic field control through multi-dimensional, multi-unit magnetic field manipulation, a feat unattainable by planar coil arrays or single 3D coils.

[0035] The spherical structure can form a high-freedom, omnidirectional electromagnetic field in three-dimensional space, improving the ability to control the direction of the synthetic magnetic field.

[0036] The cone structure can improve the directional focusing ability of magnetic field energy.

[0037] The direction of the synthetic magnetic field can be scanned arbitrarily in the half space, and the magnetic field amplitude can be finely controlled.

[0038] After the user sets the synthetic magnetic field's azimuth, frequency, and amplitude, or based on the desired magnetic field's azimuth, frequency, and amplitude, the central control system's built-in algorithm calculates the control parameters for each coil unit and sends this information to the control module of each 3D coil unit. The unit's control module then specifically adjusts the unit's synthetic magnetic field's amplitude, frequency, phase, and other parameters, ultimately ensuring that the overall synthetic magnetic field's basic parameters meet the user's settings.

[0039] The central control system primarily consists of a coordination control module and a time synchronization module. The coordination control module is the core of the central control system and, with the assistance of other modules, enables coordinated control of the entire instrument system. The coordination control module interprets and processes user commands or requests, using an electromagnetic field coupling inverse solution algorithm to determine the control parameters for each coil unit. It then communicates commands and data with various functional modules using an extensible interface. The time synchronization module enables precise time synchronization of multi-dimensional sensors, achieving nanosecond-level accuracy.

[0040] The communication system utilizes a layered design. Wired communication is used between the central control system and the three-dimensional coil units to reduce interference. In some embodiments, the communication system employs CAN communication based on differential signaling. The protocol layer complies with the ISO11898 standard, employs a non-destructive arbitration mechanism and a multi-master communication architecture, and supports both broadcast and point-to-point transmission. Data is encapsulated in data frames (including an identifier, data length, data field, and CRC checksum), which offer advantages such as strong anti-interference capabilities.

[0041] The central control system is the master node, responsible for global scheduling and coordinating the operating modes of all coils. The control module of each 3D coil unit is a slave node, creating an overall one-master-multiple-slave model. The master node sends control instructions to each slave node. The slave nodes utilize a networking structure, enabling intercommunication and uplink / downlink communication between each other, reducing communication latency. Dynamic self-organization and collaboration between nodes offer the advantages of high reliability and flexibility. By selecting appropriate communication protocols, rational network layering, channel planning, and protocol optimization, multi-node collaboration can be effectively achieved. This provides the advantages of low power consumption and high reliability.

[0042] The power distribution system utilizes a hybrid architecture combining a main power source and distributed power supplies. Power from the main power source is distributed on demand to distributed power modules via a power distributor. Each module independently supplies power to 5-10 three-dimensional coil units. Protection mechanisms and redundant links are also designed to ensure reliable and stable power supply.

[0043] Using a power distributor, under the control of the central control system, the total power is distributed to each three-dimensional coil basic unit on demand, improving energy utilization efficiency. It has functions such as remote control, power monitoring and overload protection, and operators can monitor the power distribution status in real time.

[0044] It also includes a human-computer interaction system, which communicates with the central control system and is used to receive user configuration parameters and adjust control parameters of the central control system according to the configuration parameters.

[0045] Some human-computer interaction systems offer features such as magnetic field parameter configuration, synthetic magnetic field visualization, over-limit alarms, and historical data recording and analysis. Users can adjust synthetic magnetic field parameters such as intensity, orientation, frequency, and waveform. Algorithms then calculate and render the 3D magnetic field distribution, providing real-time feedback.

[0046] In some embodiments, the system further includes a heat dissipation component, and those skilled in the art may select an existing heat dissipation component to dissipate heat from the formed three-dimensional coil array.

[0047] The specific electromagnetic field coupling inverse solution algorithm is given below, such as Figure 4 As shown, according to the existing conclusions, the magnetic field generated by a rectangular coil at any point P(x,y,z) in space can be calculated by the following formula.

[0048] ; in , , The value of is calculated by the following formula: ; ; ; in, is the vacuum permeability, I is the current in the rectangular coil, and the remaining parameters are calculated using the following formulas: ; ; ; ; ; ; ; ; Where x, y, z are the rectangular coordinates of point P(x,y,z), and 2*a and 2*b are the lengths of the two sides of the rectangular coil.

[0049] According to the principle of magnetic field superposition, it can be deduced that in a vacuum environment, a three-dimensional coil basic unit composed of six square coils, such as Figure 2 As shown, the magnetic field generated at a point in space is: ; ; ; The side length of the square coil is 2a, and the other parameters can be derived from geometric relationships as follows: For coil 1, the parameters are as follows: ; ; ; ;

[0050]

[0051]

[0052]

[0053] For coil 2, the parameters are as follows:

[0054]

[0055]

[0056]

[0057]

[0058]

[0059] For coil 3, the parameters are as follows:

[0060]

[0061]

[0062]

[0063]

[0064]

[0065] For coil 4, the parameters are as follows:

[0066]

[0067]

[0068]

[0069]

[0070]

[0071] For coil 5, the parameters are as follows:

[0072]

[0073]

[0074]

[0075]

[0076]

[0077] For coil 6, the parameters are as follows:

[0078]

[0079]

[0080]

[0081]

[0082]

[0083] Considering the uniqueness of the solution of the linear equation system, write down the magnetic induction intensity and direction at two points in space. , , is the three-component magnetic induction intensity at point 1. , , is the three-component magnetic induction intensity at point 2. Based on this, the following linear equations and their matrix forms can be obtained, where e is an element in the matrices Ax, Ay, and Az:

[0084]

[0085]

[0086]

[0087]

[0088]

[0089]

[0090] in

[0091]

[0092]

[0093] Among them, matrix B is the desired magnetic field distribution matrix, I is the current distribution matrix, and the final target current distribution matrix I can be obtained by the following inverse operation:

[0094] According to the formula, limited by the number of equations and unknowns, the three-dimensional coil basic unit can accurately control the magnetic field strength and direction at two points.

[0095] like Figure 5 As shown, in the target frequency band, the equivalent circuit model of the coil is a series connection of an inductor and a resistor. Without considering other electrical components, its impedance is expressed as follows:

[0096] in, is the equivalent resistance of the nth coil, is the equivalent inductance of the nth coil. According to Kirchhoff's voltage law, the current-voltage relationship of the coil can be obtained.

[0097] ; in, is the current flowing through the nth coil, is the voltage applied across the nth coil, is the mutual inductance between the mth and nth coils. When the coils' shapes, spatial positions, and the medium in between are determined, the mutual inductance is uniquely determined and measurable. Its sign is determined by whether the magnetic field generated by coil m enhances the magnetic field generated by coil n.

[0098] Based on the relationship between the magnetic field, excitation current, and excitation voltage generated by the three-dimensional coil basic unit in space, we can further deduce that the three-dimensional coil array is obtained by freely combining n three-dimensional coil basic units. The electromagnetic field excited at a certain point in space is obtained by superimposing the electromagnetic fields excited by the corresponding number of three-dimensional coil basic units, as follows:

[0099] in, , , are the x, y, and z components of the magnetic induction intensity generated by the nth three-dimensional coil basic unit at that point. To ensure that the linear equation system has a unique solution, a relationship matrix between 2*n points in space and the distributed current can be listed.

[0100]

[0101] Where A is the relationship matrix between 2*n points in space and the distributed current of the three-dimensional coil array. Its internal element e can be derived from the magnetic field formula generated by the rectangular coil at a certain point. B is the desired magnetic field matrix, and I is the distributed current matrix.

[0102] ; ; ; in, , , is the three-component magnetic induction intensity excited by the three-dimensional coil array at the nth point, is the excitation current in the nth rectangular coil.

[0103] Therefore, by first setting the magnetic induction intensity and direction of the magnetic field at 2*n points in space, we can calculate the excitation current in the 6*n coils under this condition. Then, based on the above current-voltage relationship, we can derive the excitation voltage to be applied.

[0104] The above derivation shows that a three-dimensional coil array composed of n three-dimensional coil basic units can control the magnetic induction intensity and direction at a maximum of 2*n points on a reference surface. Taking into account the mutual inductance interference between coils, the magnetic induction intensity and direction at 2*n points can be set within a reasonable range. The excitation current amplitude and direction in each rectangular coil in the three-dimensional coil array can then be reversely calculated. The excitation voltage that should be applied to the coil load can then be deduced from the relationship matrix between the excitation current and the excitation voltage, thereby achieving the three-dimensional coil array to excite a controllable electromagnetic field in space.

[0105] Example 2 The working method of the system provided in the first embodiment includes the following steps: The central control system calculates the control parameters of each three-dimensional coil basic unit based on the required parameters of electromagnetic excitation and the size and shape of the three-dimensional coil array, and sends the calculated control parameters to the corresponding three-dimensional coil basic unit through the communication system. The corresponding three-dimensional coil basic unit adjusts the transmission current according to the control parameters. The power distribution system determines the power supply requirements of each distributed power module based on the control parameters calculated by the central control system, and provides stable power supply for each three-dimensional coil basic unit; In response to a user configuration request, the control parameters of the central control system are adjusted according to the configuration parameters in the configuration request, thereby adjusting the transmission current parameters of each three-dimensional coil basic unit.

[0106] As an optional implementation, the process of calculating the control parameters of each three-dimensional coil basic unit based on the required parameters of electromagnetic excitation and the size and shape of the three-dimensional coil array includes: controlling the magnetic induction intensity and direction at a maximum of 2*n points on a reference surface of a three-dimensional coil array composed of n three-dimensional coil basic units, setting the magnetic induction intensity and direction at 2*n points within a reasonable range while considering the mutual inductance interference between coils, and using the electromagnetic field coupling inverse solution algorithm to reversely calculate the excitation current amplitude and direction in each rectangular coil in the three-dimensional coil array to obtain the control parameters, thereby enabling the three-dimensional coil array to excite a directional electromagnetic field in space.

[0107] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of one or more computer-usable storage media (including but not limited to disk storage, CD - ROM , optical storage, etc.).

[0108] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0109] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0110] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0111] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made by those skilled in the art that fall within the spirit and principles of the present invention and do not require creative effort are intended to be within the scope of protection of the present invention.

Claims

1. A controllable electromagnetic excitation system based on a combined three-dimensional coil array, characterized in that: It includes a three-dimensional coil array, a central control system, a communication system, and a power distribution system, including: The three-dimensional coil array includes a plurality of three-dimensional coil basic units, each of which is arranged in sequence to form a three-dimensional structure. Each three-dimensional coil basic unit includes three groups of orthogonal Helmholtz coils to form a cubic structure. The three groups of orthogonal Helmholtz coils are used to provide three orthogonal magnetic field components, and the control parameters of the transmission current of each Helmholtz coil are adjustable. The central control system is used to calculate the control parameters of each three-dimensional coil basic unit based on the required parameters of electromagnetic excitation and the size and shape of the three-dimensional coil array, and send the calculated control parameters to the corresponding three-dimensional coil basic unit through the communication system to change the control parameters; The power distribution system includes a power distributor and multiple distributed power modules. The power distributor determines the power supply requirements of each distributed power module based on the control parameters calculated by the central control system. Each distributed power module independently supplies power to several three-dimensional coil basic units under the control of the power distributor.

2. A controllable electromagnetic excitation system based on a combined three-dimensional coil array as claimed in claim 1, characterized in that: Each three-dimensional coil basic unit also includes a transmission excitation module, a transmission current waveform recording module, a control module, a communication module and a power supply module, wherein the transmission excitation module is used to realize the transmission waveform frequency, phase and amplitude modulation; The transmitting current waveform recording module is used to detect the amplitude, frequency and phase of the transmitting current in the Helmholtz coil and transmit them to the control module; The control module is used to control the transmitting excitation module to adjust the amplitude, frequency and phase of the transmitting current of the Helmholtz coil according to the calculated control parameters, and receive the detection data fed back by the transmitting current waveform recording module to perform automatic adjustment; The communication module is used to provide a communication path for the control module and other modules; The power supply module is used to provide a DC voltage to the Helmholtz coil.

3. A controllable electromagnetic excitation system based on a combined three-dimensional coil array as claimed in claim 2, characterized in that: The transmitting excitation module includes an impedance matching circuit, a full-bridge inverter circuit, a driving circuit and a signal isolation circuit, wherein the impedance matching circuit is used to perform impedance matching with the Helmholtz coil; The full-bridge inverter circuit is used to generate a transmission waveform and is controlled by a control module using pulse width modulation technology. The output voltage and waveform are controlled by adjusting the conduction pulse width of the switching devices in the full-bridge inverter circuit. The driving circuit is used to amplify the control signal of the control module to drive the full-bridge inverter to work; The signal isolation circuit is used to isolate the connection between the drive circuit and the full-bridge inverter circuit.

4. The controllable electromagnetic excitation system based on a combined three-dimensional coil array according to claim 1, characterized in that: The communication system adopts a hierarchical structure. The central control system is a master node for global scheduling and coordinating the working modes of all three-dimensional coil basic units. The control module of each three-dimensional coil basic unit is a slave node. The master node sends control instructions to each slave node. The slave nodes form a networking structure and can communicate with each other.

5. The controllable electromagnetic excitation system based on a combined three-dimensional coil array according to claim 1, characterized in that: The spacing between adjacent three-dimensional coil basic units is within the set range; Several temperature sensors are arranged inside and / or around the three-dimensional coil array.

6. The controllable electromagnetic excitation system based on a combined three-dimensional coil array according to claim 1, characterized in that: It also includes a heat dissipation system, which includes several heat dissipation substrates. Micro-channels are laser-engraved on the surface of each heat dissipation substrate and embedded with carbon nanotube-reinforced phase change material.

7. The controllable electromagnetic excitation system based on a combined three-dimensional coil array according to claim 1, characterized in that: It also includes a human-computer interaction system, which communicates with the central control system and is used to receive user configuration parameters and adjust control parameters of the central control system according to the configuration parameters.

8. A working method based on the system according to any one of claims 1 to 7, characterized in that: The following steps are involved: The central control system calculates the control parameters of each three-dimensional coil basic unit based on the required parameters of electromagnetic excitation and the size and shape of the three-dimensional coil array, and sends the calculated control parameters to the corresponding three-dimensional coil basic unit through the communication system. The corresponding three-dimensional coil basic unit adjusts the transmission current according to the control parameters. The power distribution system determines the power supply requirements of each distributed power module based on the control parameters calculated by the central control system, and provides stable power supply for each three-dimensional coil basic unit; In response to a user configuration request, the control parameters of the central control system are adjusted according to the configuration parameters in the configuration request, thereby adjusting the transmission current parameters of each three-dimensional coil basic unit.

9. The method according to claim 8, wherein: The process of calculating the control parameters of each three-dimensional coil basic unit based on the required parameters of electromagnetic excitation and the size and shape of the three-dimensional coil array includes: controlling the magnetic induction intensity and direction at a maximum of 2*n points on a reference surface of a three-dimensional coil array composed of n three-dimensional coil basic units; setting the magnetic induction intensity and direction at the 2*n points within a reasonable range while considering the mutual inductance interference between the coils; and using the electromagnetic field coupling inverse solution algorithm to reversely calculate the excitation current amplitude and direction in each rectangular coil in the three-dimensional coil array to obtain the control parameters, thereby realizing the three-dimensional coil array exciting a directional electromagnetic field in space.

10. The method according to claim 8, wherein: The process of calculating the control parameters of each three-dimensional coil basic unit based on the required parameters of electromagnetic excitation and the size and shape of the three-dimensional coil array includes: based on the relationship between the magnetic field generated by the three-dimensional coil basic unit in space and the excitation current and excitation voltage, deriving the three-dimensional coil array obtained by freely combining n three-dimensional coil basic units, and the electromagnetic field excited by the three-dimensional coil array at a certain point in space is obtained by superimposing the electromagnetic fields excited by the corresponding number of three-dimensional coil basic units: in, , , are the x-component, y-component, and z-component of the magnetic induction intensity generated by the n-th three-dimensional coil basic unit at this point. To ensure that the linear equations have a unique solution, the relationship matrix between the 2*n points in space and the distributed current is listed: Where A is the relationship matrix between 2*n points in space and the distributed current of the three-dimensional coil array. Its internal element e is derived from the magnetic field formula generated by the rectangular coil at a certain point. B is the expected magnetic field matrix, and I is the distributed current matrix. ； ； ； in, , , is the three-component magnetic induction intensity excited by the three-dimensional coil array at the nth point, is the excitation current in the nth rectangular coil; Given the magnetic induction intensity and direction of the magnetic field at 2*n points in space, find the excitation current in 6*n coils under this condition. Under the condition that the excitation current and the physical laws of the electromagnetic field are satisfied, the magnetic induction intensity and direction of the magnetic field at 2*n points can be arbitrarily set, which can realize the control of the synthetic magnetic field intensity and direction to a certain extent. After obtaining the distributed current of the three-dimensional coil array, the excitation voltage is obtained by Kirchhoff's voltage law, taking into account the mutual inductance of the coils. The current-voltage relationship is as follows: in, is the current flowing through the nth coil, is the voltage applied across the nth coil, is the mutual inductance between the mth coil and the nth coil, is the impedance of the nth coil circuit. When the shape, spatial position and medium in the space of the coil are determined, the mutual inductance is uniquely determined and can be measured. Its sign is determined by whether the magnetic field generated by coil m enhances the magnetic field generated by coil n.

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