A controllable electromagnetic excitation system and method based on a combined three-dimensional coil array

Abstract

The present application belongs to the technical field of geophysical electromagnetic 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 demand parameters of electromagnetic excitation, size and shape of the three-dimensional coil array. The corresponding three-dimensional coil basic unit adjusts the emission current according to the control parameters. A power distribution system determines the power supply demand of each distributed power module according to 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, and then the emission current parameters of each three-dimensional coil basic unit are adjusted. The present application realizes accurate electromagnetic field control by physically combining the three-dimensional coil basic unit in space and adjusting the emission current amplitude, phase and frequency according to actual needs.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of geophysical electromagnetic exploration, and particularly relates to a controllable electromagnetic excitation system and method based on a combined three-dimensional coil array. BACKGROUND

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

[0003] Geophysical electromagnetic exploration generally utilizes the conductivity and dielectricity difference of rock and ore body and other media, analyzes the received electromagnetic response signals by using electromagnetic induction principle, and inverts the underground electrical structure. According to the field source form, electromagnetic detection methods can be divided into natural field source (passive source) electromagnetic method, artificial source (active source) electromagnetic method and mixed field source electromagnetic method combining controllable source and natural source. Among them, the artificial source electromagnetic method has the advantages of flexibility, controllability, high signal-to-noise ratio and strong anti-interference ability, so it is widely used in the fields of mineral exploration, rail transit construction and engineering geological survey.

[0004] At present, domestic and foreign scholars mainly focus on the following aspects in the research of artificial source electromagnetic method excitation device:

[0005] 1) By developing a power amplifier with larger power, the transmitting current is improved to realize large energy excitation;

[0006] 2) Resonance matching of the transmitting coil is used to improve the transmitting current;

[0007] 3) Distributed transmitting coil array such as cone coil array is used to focus the magnetic field and improve the transmitting magnetic field energy.

[0008] However, due to the high-frequency inductance of the coil, blindly increasing the voltage across the transmitting coil cannot effectively improve the transmitting current, and thus cannot effectively improve the excited electromagnetic field energy, nor can it adjust the energy of the excited electromagnetic field according to the needs of the detection target.

[0009] And using the transmitting coil resonance matching technology, the number of available frequency points is small, the switching channel is complex, and the detection efficiency is affected.

[0010] In addition, the effect of focusing the magnetic field by using the cone coil array is limited, and the direction of the magnetic field cannot be changed without moving the physical device, so it is impossible to realize omnidirectional detection in a limited space.

[0011] In summary, the existing technology has the problems of limited excitation energy, poor controllability and low recognition, which makes it difficult to support the detection of deep and long-distance geological environment. SUMMARY

[0012] The application proposes a controllable electromagnetic excitation system and method based on a combined three-dimensional coil array to solve the above problems.

[0013] According to some embodiments, the application adopts the following technical solutions:

[0014] 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:

[0015] The three-dimensional coil array includes a plurality of three-dimensional coil basic units, each three-dimensional coil basic unit is sequentially arranged to form a three-dimensional structure, and each three-dimensional coil basic unit includes three sets of orthogonal Helmholtz coils to form a cubic structure.

[0016] The central control system is used to calculate the control parameters of each three-dimensional coil basic unit according to the demand parameters of electromagnetic excitation, the size and shape of the three-dimensional coil array, and send the control parameters to the corresponding three-dimensional coil basic unit through the communication system to change the control parameters.

[0017] The power distribution system includes a power distributor and a plurality of distributed power modules.

[0018] 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 module.

[0019] The transmission current waveform recording module is used to detect the amplitude, frequency, and phase of the transmission current in the Helmholtz coil and transmit the detection data to the control module.

[0020] The control module is used to control the transmission excitation module to adjust the amplitude, frequency, and phase of the transmission current of the Helmholtz coil according to the calculated control parameters and receive the detection data fed back by the transmission current waveform recording module for automatic adjustment.

[0021] The communication module is used to provide a communication path for the control module and other modules.

[0022] The power module is configured to provide a direct current voltage for the Helmholtz coil.

[0023] As a further defined embodiment, the transmitting excitation module comprises an impedance matching circuit, a full-bridge inverter circuit, a driving circuit and a signal isolation circuit, wherein the impedance matching circuit is configured to match the impedance of the Helmholtz coil;

[0024] The full-bridge inverter circuit is configured to generate a transmitting waveform, which is controlled by the control module using a pulse width modulation technique, and the size and waveform of the output voltage are controlled by adjusting the conduction pulse width of the switching device in the full-bridge inverter circuit.

[0025] The driving circuit is configured to amplify the control signal of the control module to drive the full-bridge inverter to work.

[0026] The signal isolation circuit is configured to isolate the connection between the driving circuit and the full-bridge inverter circuit.

[0027] As an optional embodiment, the communication system adopts a hierarchical structure, the central control system is a master node, which is configured to perform global scheduling and coordinate the working mode 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, and each slave node is in a networking structure and can communicate with each other.

[0028] As an optional embodiment, the spacing between adjacent three-dimensional coil basic units is within a set range.

[0029] As an optional embodiment, the system further comprises a human-computer interaction system, which communicates with the central control system and is configured to receive configuration parameters of a user and adjust the control parameters of the central control system according to the configuration parameters.

[0030] The working method based on the above system comprises the following steps:

[0031] The central control system calculates the control parameters of each three-dimensional coil basic unit according to the demand parameters of electromagnetic excitation, the size and shape of the three-dimensional coil array, and sends the control parameters to the corresponding three-dimensional coil basic unit through the communication system, and the corresponding three-dimensional coil basic unit adjusts the transmitting current according to the control parameters.

[0032] The power distribution system determines the power supply demand of each distributed power module according to the control parameters calculated by the central control system, and provides stable power supply for each three-dimensional coil basic unit.

[0033] In response to the 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 each three-dimensional coil basic unit are adjusted.

[0034] As an alternative embodiment, according to the demand parameters of electromagnetic excitation, 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: the three-dimensional coil array composed of n three-dimensional coil basic units controls the magnetic induction intensity and direction at most 2*n points on the reference surface, sets the magnetic induction intensity and direction at 2*n points within a reasonable range considering the mutual inductance interference between coils, and reversely calculates the excitation current amplitude and direction in each rectangular coil in the three-dimensional coil array by using the electromagnetic field coupling reverse solving algorithm to obtain the control parameters and realize the excitation of directional electromagnetic field in space by the three-dimensional coil array.

[0035] As further, according to the demand parameters of electromagnetic excitation, 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: according to the relationship between the magnetic field generated by the three-dimensional coil basic unit in space and the excitation current and excitation voltage, the three-dimensional coil array obtained by freely combining n three-dimensional coil basic units is derived, 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:

[0036] ;

[0037] Wherein, , , is the x component, y component and z component of the magnetic induction intensity generated by the nth three-dimensional coil basic unit at the point, in order to ensure that the linear equation set has a unique solution, the relationship matrix of 2*n points in space and distributed current is listed:

[0038] ；

[0039] Wherein A is the relationship matrix of 2*n points in space and distributed current of three-dimensional coil array, the internal element e is derived from the magnetic field formula of rectangular coil at a certain point, B is the expected magnetic field matrix, and I is the distributed current matrix.

[0040] ;

[0041] ;

[0042] ;

[0043] Wherein, , , Three-component magnetic induction intensity excited by the three-dimensional coil array at the nth point, Excitation current in the nth rectangular coil;

[0044] The magnetic induction intensity and direction of the magnetic field at 2*n points in the space are set, and the excitation current in the 6*n coils is obtained under the condition;

[0045] In the case of satisfying the physical law of excitation current and electromagnetic field, the magnetic induction intensity and direction of the magnetic field at 2*n points are set arbitrarily, and the control of the synthesized magnetic field intensity and direction can be achieved to a certain extent, and after obtaining the distribution current of the three-dimensional coil array, the excitation voltage is obtained by considering the mutual inductance of the coil according to the Kirchhoff voltage law, and the current-voltage relationship is as follows:

[0046]

[0047] Wherein, The current flowing through the nth coil, The voltage applied across the nth coil, The mutual inductance between the mth coil and the nth coil, The nth coil circuit impedance, when the shape, spatial position and medium in the space of the coil are determined, the mutual inductance is uniquely determined, and is measured, and the sign is determined by whether the magnetic field generated by the coil m enhances the magnetic field generated by the coil n.

[0048] Compared with the prior art, the beneficial effects of the present application are:

[0049] The present application adopts the flexible combination of three-dimensional coil array, and according to the needs of users, the three-dimensional coil basic unit can be arbitrarily combined to form a three-dimensional coil array with variable shape. Through the electromagnetic field coupling reverse solving algorithm, a fine controllable complex electromagnetic field can be formed in the space.

[0050] The present application uses the electromagnetic field coupling reverse solving algorithm, and can set the magnetic field parameters or required magnetic field parameters according to the user, and reversely solve the control parameters of each three-dimensional coil basic unit of the arbitrarily combined three-dimensional coil array.

[0051] In order to make the above-mentioned purposes, characteristics and advantages of the present application more obvious and easy to understand, the following preferred embodiments are described in detail below, and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0052] The drawings accompanying the specification form a part of the present application and serve to provide further understanding of the present application, the exemplary embodiments of the present application and their descriptions serve to explain the present application, and do not constitute improper limitation on the present application.

[0053] Figure 1 ​Fig. 1 is a schematic diagram of a three-dimensional coil basic unit structure in an embodiment;

[0054] Figure 2 Fig. 2 is a schematic diagram of a cubic three-dimensional coil array in an embodiment;

[0055] Figure 3 Fig. 3 is a schematic diagram of a spherical three-dimensional coil array in an embodiment;

[0056] Figure 4 Fig. 4 is a schematic diagram of a rectangular coil and a point P(x, y, z) in an embodiment;

[0057] Figure 5 Fig. 5 is a schematic diagram of an equivalent circuit model considering mutual inductance of coils in an embodiment. DETAILED DESCRIPTION

[0058] The application will be further described below in conjunction with the drawings and embodiments.

[0059] It should be noted that the following detailed description is illustrative only, and is intended to provide further description in order to provide a further understanding of the exemplary embodiments of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the application pertains.

[0060] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0061] The embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0062] Embodiment One

[0063] A controllable electromagnetic excitation system based on a combined three-dimensional coil array, comprising a three-dimensional coil array, a central control system, a communication system and a power distribution system, wherein:

[0064] The three-dimensional coil array comprises a plurality of three-dimensional coil basic units, each three-dimensional coil basic unit is arranged in sequence to form a three-dimensional structure, as shown in Figure 1 Each three-dimensional coil basic unit comprises three sets of orthogonal Helmholtz coils to form a cubic structure, the three sets of orthogonal Helmholtz coils are used to provide three orthogonal magnetic field components, and the control parameters of the emission currents of the Helmholtz coils are adjustable;

[0065] The central control system is configured to calculate control parameters of each three-dimensional coil basic unit according to the demand parameters of electromagnetic excitation, the size and shape of the three-dimensional coil array, and send the control parameters to the corresponding three-dimensional coil basic unit through the communication system to change the control parameters.

[0066] The power distribution system includes a power distributor and a plurality of distributed power modules. The power distributor determines the power supply requirements of each distributed power module according to the control parameters calculated by the central control system. Each distributed power module independently supplies power to a plurality of three-dimensional coil basic units under the control of the power distributor.

[0067] 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 module. The three orthogonal Helmholtz coils can provide three orthogonal magnetic field components, and the size of the magnetic field component is proportional to the size of the transmission current passing through the coil. Therefore, a directional electromagnetic field can be formed in space by controlling the amplitude of the transmission current.

[0068] The transmission excitation module is used to realize the frequency, phase, and amplitude modulation of the transmission waveform, including an impedance matching circuit, a full-bridge inverter circuit, a driving circuit, and a signal isolation circuit. The impedance matching circuit matches the impedance of the transmission coil to reduce signal reflection and energy loss and improve energy transmission efficiency.

[0069] The full-bridge inverter circuit is used to generate the transmission waveform, which is controlled by the control module using the pulse width modulation (PWM) technique. By adjusting the on-pulse width of the switching device, the size and waveform of the output voltage can be accurately controlled, which is simple and easy to implement.

[0070] Since the voltage generated by the control module is not sufficient to directly drive the full-bridge inverter, a driving circuit is used to amplify the voltage to drive the full-bridge inverter. On the other hand, the high voltage in the full-bridge inverter circuit can easily interfere with the low voltage in the control module through the driving circuit, so a signal isolation circuit is needed to isolate the connection between the driving signal and the switching device of the full-bridge inverter circuit.

[0071] The transmission current waveform recording module is used to detect the amplitude, frequency, and phase of the coil transmission current in the three-dimensional coil basic unit in real time and transmit the information to the control module in real time. The control module is composed of a main control unit and a power management unit. The main control unit controls the full-bridge inverter and adjusts the amplitude, frequency, and phase of the transmission current. The information collected by the transmission current waveform recording module is received and automatically adjusted through a feedback mechanism to improve the stability of the system. The power module uses switching power supply devices to provide stable DC voltage for the entire system.

[0072] A series of three-dimensional coil basic units can be freely combined in space to form a spherical body (such asFigure 3 As shown), cube (as shown) Figure 2 As shown, structures such as cones form complex combined three-dimensional coil arrays in space. A controllable electromagnetic excitation system composed of a series of freely combined three-dimensional coil basic units can achieve more precise magnetic field control through multi-dimensional, multi-unit magnetic field modulation, which is unattainable by planar coil arrays or single three-dimensional coils.

[0073] The spherical structure can form a highly free, omnidirectional electromagnetic field in three-dimensional space, improving the ability to control the direction of the synthesized magnetic field.

[0074] The cone structure can improve the ability to focus magnetic field energy.

[0075] The direction of the synthesized magnetic field can be scanned arbitrarily within half-space, and the magnetic field amplitude can be finely controlled.

[0076] After the user sets the azimuth, frequency, and amplitude of the synthesized magnetic field, or according to the required magnetic field parameters, the central control system's built-in algorithm calculates the control parameters for each basic coil unit and packages the information to send to the control module of each three-dimensional coil unit. The basic unit control module then specifically adjusts the amplitude, frequency, phase, and other parameters of the synthesized magnetic field of its unit, ultimately ensuring that the basic parameters of the overall synthesized magnetic field conform to the user's settings.

[0077] The central control system mainly consists of a coordination control module and a time synchronization module. The coordination control module is the core of the central control system, achieving coordinated control of the entire instrument system with the assistance of other modules. It parses and processes user commands or requirements, uses an electromagnetic field coupling inverse algorithm to parse the control parameters of each basic coil unit, and uses an expandable interface to transmit commands and data to various functional modules. The time synchronization module enables precise time synchronization of multi-dimensional sensors, with a time synchronization accuracy down to the nanosecond level.

[0078] The communication system adopts a layered design. Wired communication is used between the central control system and the three-dimensional coil basic unit to reduce interference. In some embodiments, the communication system uses CAN communication based on differential signal transmission, with the protocol layer following the ISO11898 standard. It employs a non-destructive arbitration mechanism and a multi-master communication architecture, supporting broadcast or point-to-point transmission. Data is encapsulated in data frames (including identifiers, data length, data fields, and CRC checksums), offering advantages such as strong anti-interference capabilities.

[0079] The central control system is a master node, responsible for global scheduling and coordinating the working mode of all coils. The control module of each three-dimensional coil basic unit is a slave node, and the overall mode is a master-slave mode. The master node sends control instructions to each slave node. The slave nodes use a networking structure, and each slave node can communicate with each other, upload and issue, reducing communication delay. The nodes dynamically self-organize and cooperate, with the advantages of high reliability and high flexibility. By selecting the corresponding communication protocol, through reasonable network layering, channel planning and protocol optimization, the collaborative work of multiple nodes can be effectively realized. It has the advantages of low power consumption and high reliability.

[0080] The power distribution system adopts a hybrid power supply architecture of main power supply plus distributed power supply. The main power supply power is distributed to the distributed power supply module as needed through the power distributor, and each module independently supplies power to 5-10 three-dimensional coil basic units. A protection mechanism and redundant link are designed to ensure reliable and stable power supply.

[0081] Using the power distributor, the total power supply power is distributed to each three-dimensional coil basic unit as needed under the control of the central control system, improving energy utilization efficiency, and having functions such as remote control, power monitoring and overload protection. The operator can monitor the power distribution state in real time.

[0082] It also includes a human-computer interaction system that communicates with the central control system and is used to receive user configuration parameters and adjust the control parameters of the central control system according to the configuration parameters.

[0083] Part of the human-computer interaction system has functions such as magnetic field parameter configuration, synthesized magnetic field visualization, over-limit alarm, and historical data recording and analysis. Users can adjust the synthesized magnetic field strength, orientation, frequency and waveform parameters by themselves, and the corresponding algorithm calculates and renders the 3D space magnetic field distribution, and feeds back to the user in real time.

[0084] In some embodiments, the system also includes a heat dissipation component, and those skilled in the art can use existing heat dissipation components to dissipate heat from the formed three-dimensional coil array.

[0085] A specific electromagnetic field coupling inverse solving algorithm is given below, as shown in Figure 4 According to 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.

[0086] ;

[0087] Where , , The value is calculated by the following formula:

[0088] ;

[0089] ;

[0090] ;

[0091] where μ0 is the vacuum permeability, I is the current in the rectangular coil, and the other parameters are calculated by the following equations:

[0092] ;

[0093] ;

[0094] ;

[0095] ;

[0096] ;

[0097] ;

[0098] ;

[0099] ;

[0100] where x, y, z are the rectangular coordinates of point P(x, y, z), and 2a, 2b are the lengths of the two sides of the rectangular coil.

[0101] According to the principle of superposition of magnetic fields, it can be deduced that in a vacuum environment, a three-dimensional coil basic unit composed of six square coils, as shown in Figure 2 , generates a magnetic field at a point in space as follows:

[0102] ;

[0103] ;

[0104] ;

[0105] where the side length of the square coil is 2a, and the other parameters can be derived from geometric relationships, as follows:

[0106] For coil 1, the parameters are as follows:

[0107] ;

[0108] ;

[0109] ;

[0110] ​ ;

[0111]

[0112]

[0113]

[0114]

[0115] For coil 2, the parameters are as follows:

[0116]

[0117]

[0118]

[0119]

[0120]

[0121]

[0122] For coil 3, the parameters are as follows:

[0123]

[0124]

[0125]

[0126]

[0127]

[0128]

[0129] For coil 4, the parameters are as follows:

[0130]

[0131]

[0132]

[0133]

[0134]

[0135]

[0136] For coil 5, the parameters are as follows:

[0137]

[0138]

[0139]

[0140]

[0141]

[0142]

[0143] For coil 6, the parameters are as follows:

[0144]

[0145]

[0146]

[0147]

[0148]

[0149]

[0150] Considering the uniqueness of the solution of the linear equations, write the magnetic induction intensity and direction at two points in space, , , is the three-component magnetic induction intensity of point 1. , , is the three-component magnetic induction intensity of point 2. Accordingly, the following linear equations and matrix form can be obtained, e is the element in the matrix Ax, Ay, Az:

[0151]

[0152]

[0153]

[0154]

[0155]

[0156]

[0157]

[0158] wherein

[0159]

[0160]

[0161]

[0162] wherein, matrix B is the desired magnetic field distribution matrix, I is the current distribution matrix, the current distribution matrix I as the final goal can be obtained by the following inverse operation:

[0163]

[0164] According to the formula, limited by the number of equations and the number of unknowns, the three-dimensional coil basic unit can accurately control the magnetic field intensity and its direction at certain two points.

[0165] As Figure 5 shown, in the target frequency band, the equivalent circuit model of the coil is a series of inductance and resistance, and its impedance is represented as follows without considering other electrical elements:

[0166]

[0167] wherein, 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.

[0168] ;

[0169] wherein, 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. When the shape, spatial position and medium in 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.

[0170] According to the relationship between the magnetic field generated by the three-dimensional coil basic unit in space and the exciting current, the exciting voltage which has been derived, the electromagnetic field excited by the three-dimensional coil array composed of n three-dimensional coil basic units at a certain point in space can be further derived by superimposing the electromagnetic fields excited by the corresponding number of three-dimensional coil basic units, as follows:

[0171]

[0172] wherein, , , is the x component, y component and z component of the magnetic induction produced by the nth three-dimensional coil basic unit at the point. To ensure that the linear equation set has a unique solution, a relationship matrix of 2*n points in space and the distributed current can be listed.

[0173]

[0174] wherein A is a relationship matrix of 2*n points in space and the three-dimensional coil array distributed current, the internal element e can be derived from the magnetic field formula produced by the rectangular coil at a certain point, B is the expected magnetic field matrix, and I is the distributed current matrix.

[0175]

[0176]

[0177]

[0178] wherein, , , is the three-component magnetic induction excited by the three-dimensional coil array at the nth point, is the excitation current in the nth rectangular coil.

[0179] Therefore, the magnetic induction and direction of the magnetic field at 2*n points in space are first set, and the excitation current in the 6*n coils under the condition can be obtained. By the current-voltage relationship, the excitation voltage to be applied can be obtained.

[0180] From the above derivation, a three-dimensional coil array composed of n three-dimensional coil basic units can control the magnetic induction and direction at 2*n points on the reference surface at most. In the case of considering the mutual inductance interference between coils, the magnetic induction and direction at 2*n points can be set within a reasonable range, and the excitation current amplitude and direction in each rectangular coil in the three-dimensional coil array are calculated reversely, and the excitation voltage to be applied to the coil load can be derived from the relationship matrix of the excitation current and the excitation voltage, so as to realize the three-dimensional coil array to excite a controllable electromagnetic field in space.

[0181] Embodiment Two

[0182] The working method based on the system provided in Embodiment One comprises the following steps:

[0183] ​​​The central control system calculates the control parameters of each three-dimensional coil basic unit according to the demand parameters of electromagnetic excitation, the size and shape of the three-dimensional coil array, and sends the control parameters to the corresponding three-dimensional coil basic unit through the communication system. The corresponding three-dimensional coil basic unit adjusts the emission current according to the control parameters.

[0184] The power distribution system determines the power supply demand of each distributed power module according to the control parameters calculated by the central control system, and provides stable power supply for each three-dimensional coil basic unit.

[0185] 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 each three-dimensional coil basic unit are adjusted.

[0186] As an optional implementation, the process of calculating the control parameters of each three-dimensional coil basic unit according to the demand parameters of electromagnetic excitation, the size and shape of the three-dimensional coil array includes: the three-dimensional coil array composed of n three-dimensional coil basic units controls the magnetic induction intensity and direction of at most 2*n points on the reference surface, sets the magnetic induction intensity and direction of the 2*n points within a reasonable range considering the mutual inductance interference between coils, and reversely calculates the excitation current amplitude and direction in each rectangular coil in the three-dimensional coil array by using an electromagnetic field coupling reverse solving algorithm to obtain the control parameters and realize the excitation of the three-dimensional coil array in space.

[0187] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer usable storage media (including but not limited to magnetic disk storage, optical storage, etc.) containing computer usable program code. CD - ROM , optical storage, etc.).

[0188] The present application is described with reference to flowcharts and / or block diagrams according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows 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 the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices produce a machine that implements the flowcharts and / or block diagrams. Figure 1 Each flow or multiple flows and / or blocks Figure 1means for performing the function specified by the block or blocks.

[0189] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the flow Figure 1 flow or flows and / or blocks Figure 1 means for performing the function specified by the block or blocks.

[0190] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the flow Figure 1 flow or flows and / or blocks Figure 1 steps of means for performing the function specified by the block or blocks.

[0191] The above description is only preferred embodiments of the present application, not for limiting the present application. Any modification, equivalent replacement, improvement, etc. made by those skilled in the art within the spirit and principle of the present application without creative effort should be included in the protection scope of the present application.

Claims

1. A controllable electromagnetic excitation system based on a combined three-dimensional coil array, characterized in that, The system comprises a three-dimensional coil array, a central control system, a communication system and a power distribution system, wherein: The three-dimensional coil array comprises a plurality of three-dimensional coil basic units, each of which is sequentially arranged and physically combined in space to form a three-dimensional structure of various shapes. Each three-dimensional coil basic unit comprises three sets of orthogonal Helmholtz coils to form a cubic structure. The three sets of orthogonal Helmholtz coils are used to provide three orthogonal magnetic field components. The control parameters of the emission current of each Helmholtz coil are adjustable, including the amplitude, phase and frequency of the emission current. The central control system is used to calculate the control parameters of each three-dimensional coil basic unit according to the demand parameters of electromagnetic excitation, the size and shape of the three-dimensional coil array, and the electromagnetic field coupling inverse solution algorithm. The control parameters are sent to the corresponding three-dimensional coil basic unit through the communication system to change the control parameters. The process of calculating the control parameters of each three-dimensional coil basic unit includes: the three-dimensional coil array composed of n three-dimensional coil basic units controls the magnetic induction intensity and direction of at most 2*n points on the reference surface. The magnetic induction intensity and direction of the 2*n points are set within a reasonable range considering the mutual inductance interference between coils. The electromagnetic field coupling inverse solution algorithm is used to reversely calculate the excitation current amplitude and direction of each rectangular coil in the three-dimensional coil array to obtain the control parameters, so as to realize the excitation of directional electromagnetic field in space by the three-dimensional coil array. The power distribution system comprises a power distributor and a plurality of distributed power modules. The power distributor determines the power supply demand of each distributed power module according to the control parameters calculated by the central control system. Each distributed power module independently supplies power to a plurality of three-dimensional coil basic units under the control of the power distributor. The communication system adopts a layered structure. The central control system is the master node for global scheduling and coordinating the working mode 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. Each slave node is in a networking structure and can communicate with each other.

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

3. A controllable electromagnetic excitation system based on a combined three-dimensional coil array according to claim 2, characterized in that, The transmitting excitation module comprises an impedance matching circuit, a full-bridge inverter circuit, a driving circuit and a signal isolation circuit, wherein the impedance matching circuit is used for impedance matching with the Helmholtz coil; The full-bridge inverter circuit is used for generating a transmitting waveform, which is controlled by the control module using a pulse width modulation technique, and the size and waveform of the output voltage are controlled by adjusting the conduction pulse width of the switching device in the full-bridge inverter circuit; The driving circuit is used for amplifying the control signal of the control module to drive the full-bridge inverter to work; The signal isolation circuit is used for isolating the connection between the driving circuit and the full-bridge inverter circuit.

4. A controllable electromagnetic excitation system based on a combined three-dimensional coil array as claimed in claim 1, characterized in that, The spacing between adjacent three-dimensional coil basic units is within a set range; The three-dimensional coil array is provided with a plurality of temperature sensors inside or / and around.

5. A controllable electromagnetic excitation system based on a combined three-dimensional coil array as claimed in claim 1, characterized in that, It also includes a heat dissipation system, which includes a plurality of heat dissipation substrates, each heat dissipation substrate surface is laser engraved with micro channels, and carbon nanotube reinforced phase change materials are embedded.

6. A controllable electromagnetic excitation system based on a combined three-dimensional coil array as claimed in claim 1, characterized in that, It also includes a human-computer interaction system, which communicates with the central control system and is used for receiving configuration parameters of a user and adjusting control parameters of the central control system according to the configuration parameters.

7. A method of operation of a controllable electromagnetic excitation system based on a combined three-dimensional coil array according to any one of claims 1 to 6, characterized in that The following steps are included: The central control system calculates the control parameters of each three-dimensional coil basic unit according to the demand parameters of electromagnetic excitation, the size and shape of the three-dimensional coil array, and sends the control parameters to the corresponding three-dimensional coil basic unit through the communication system, and the corresponding three-dimensional coil basic unit adjusts the transmitting current according to the control parameters; The power distribution system determines the power supply demand of each distributed power module according to 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, and then the transmitting current parameters of each three-dimensional coil basic unit are adjusted.

8. The method of claim 7 wherein, The process of calculating the control parameters of each three-dimensional coil basic unit according to the demand parameters of electromagnetic excitation, the size and shape of the three-dimensional coil array includes: the three-dimensional coil array composed of n three-dimensional coil basic units controls the magnetic induction intensity and direction at most 2*n points on the reference surface, sets the magnetic induction intensity and direction at 2*n points within a reasonable range considering the mutual inductance interference between coils, and reversely calculates the excitation current amplitude and direction in each rectangular coil in the three-dimensional coil array by using an electromagnetic field coupling reverse solving algorithm to obtain the control parameters, so as to realize the excitation of directional electromagnetic field in space by the three-dimensional coil array.

9. The method of claim 7 wherein, According to the electromagnetic excitation demand parameter, three-dimensional coil array size and shape, the process of calculating the control parameter of each three-dimensional coil basic unit includes: according to the relationship between the magnetic field generated by the three-dimensional coil basic unit in space and the excitation current, excitation voltage, the three-dimensional coil array obtained by freely combining n three-dimensional coil basic units excites the electromagnetic field at a certain point in space The electromagnetic field excited by the corresponding number of three-dimensional coil basic units is superimposed to obtain: wherein , , is the x component, the y component and the z component of the magnetic induction generated by the nth three-dimensional coil basic unit at the point, and to ensure that the linear equation system has a unique solution, the relationship matrix of 2*n points in space and the distributed current is listed: Wherein A is a relationship matrix of 2*n points in space and distributed current in the three-dimensional coil array, the internal element e is derived from the magnetic field formula of the rectangular coil at a certain point, B is the expected magnetic field matrix, and I is the distributed current matrix; ； ； ； wherein , , is the x-component, the y-component and the z-component of the three-component magnetic induction excited by the three-dimensional coil array at the nth point, is the excitation current in the nth rectangular coil; The magnetic field intensity and direction of the magnetic field at 2*n points in space are set, and the excitation current in the 6*n coils under the set condition is obtained. In the case of meeting the incentive current and electromagnetic field physical law, the magnetic induction intensity and direction of the magnetic field at 2*n points are set arbitrarily, which can control the synthetic magnetic field intensity and direction to a certain extent. After obtaining the distribution current of the three-dimensional coil array, the incentive voltage is obtained by considering the mutual inductance of the coil according to the Kirchhoff voltage law, and the current-voltage relationship is as follows: wherein, 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, is the impedance of the nth coil circuit. The mutual inductance is uniquely determined when the shape of the coils, their spatial positions and the medium in the space are determined, and is measured. The sign of the mutual inductance is determined by whether the magnetic field generated by the coil m enhances or diminishes the magnetic field generated by the coil n.

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