Magnetic field synthesis and control device and method for soil medium

Abstract

The invention discloses a magnetic field synthesis and control device and method for a soil medium, and relates to the technical field of electromagnetic field application, and the device comprises a control unit, a supporting structure and a plurality of magnetic field generation units; the plurality of magnetic field generation units are arranged in the target soil area according to the optimal spatial layout array through the supporting structure; the supporting structure is used for making the plane where the magnetic field generating units are located horizontal. The plurality of magnetic field generating units are connected with the control unit; the magnetic field generating unit is used for generating local magnetic fields; and the control unit is used for storing preset excitation parameter schemes, and controlling the plurality of magnetic field generation units according to the preset excitation parameter scheme corresponding to each magnetic field generation unit and a multi-stage energy management strategy. According to the invention, a specific spatial distribution magnetic field can be efficiently and flexibly synthesized and controlled in a soil medium.

Description

Technical Field

[0001] This application relates to the field of electromagnetic field application technology, and in particular to a device and method for magnetic field synthesis and control in soil media. Background Technology

[0002] In scenarios such as in-situ remediation of contaminated soil, geophysical exploration, and precision agriculture, it is often necessary to precisely establish a specific magnetic field distribution within a certain depth range underground to drive functional materials, stimulate response signals, or regulate biological processes. However, the spatial differences in the electrical conductivity (σ) and relative magnetic permeability (μr) of soil media are huge, and they change transiently with water content and mineral composition. This results in low-frequency magnetic fields exhibiting high attenuation and high distortion propagation characteristics in the soil, which is the primary bottleneck for implementing related technologies.

[0003] Existing technologies mostly employ a single wellbore electrode or a large surface coil to inject a magnetic field into the soil. For example, patent application CN104007476A discloses a well-to-ground electromagnetic exploration device that improves near-well resolution by emitting 8–128 Hz excitation signals through longitudinally arranged wellbore electrodes; however, its horizontal coverage decreases sharply with depth, making it difficult to obtain a large-scale uniform field. Patent application CN106001077A discloses a heavy metal chromium pollution remediation well that uses a spiral coil wound around the treatment well, maintaining a field strength of only 10–50 mT within a wellbore radius of approximately 0.6 m, which cannot meet the requirements for field-level remediation. Experimental and numerical studies show that in typical loam (σ=0.03 S / m), the 1 / e attenuation depth of a 10 Hz–10 kHz low-frequency magnetic field is typically only 1.0–1.5 m. To exceed this depth using a single-source approach, the current must be increased several times, leading to significant energy consumption and heat generation. To improve coverage, some solutions attempt to use two or more coils: The electromagnetic excitation-mutual inductance device disclosed in patent application CN110456419A reverses the connection of the main and backup coils to suppress primary field interference, but the phase difference between each coil is fixed, making it impossible to reconstruct the gradient or focus the field shape in real time; the alternating magnetic field-soil cation exchange capacity sensor disclosed in patent application CN109416344A allows for frequency sweeps of 1–100kHz, but the excitation-detection coils are rigidly coaxial, still belonging to a unidirectional field mode, making it difficult to cover complex terrain. Another type of technology focuses on near-field-shallow applications: the vehicle-mounted telescopic magnetic rod heavy metal purification device disclosed in patent application CN115069753A utilizes a magnetic rod to adsorb magnetic particles-heavy metal complexes at a depth of 0–0.3m, demonstrating the advantage of a high gradient in the near field, but it cannot solve deep pollution. Similar portable magnetization devices mostly focus on surface operations, contributing little to the field strength in deep soil (>1 m). Furthermore, environmental factors significantly affect the magnetic field distribution. Outdoor nuclear magnetic resonance (NMR) tests show that when the moisture content increases from 20% to 40%, the magnetic field uniformity error in the 1 kHz region can increase by more than 15%, indicating that transient changes in soil parameters can amplify the field distortion of single-source and rigid multi-source systems.

[0004] In summary, existing solutions struggle to balance penetration depth, field uniformity, and real-time reconfigurability. Furthermore, the lack of a global optimization array layout and closed-loop calibration mechanism based on a three-dimensional electromagnetic parameter model of the soil results in measured field shapes often deviating from design values ​​by more than 40%. Therefore, obtaining a wide-range, deep-penetrating, highly uniform, and adaptively controllable magnetic field in heterogeneous soils while maintaining acceptable power consumption remains a core technical challenge that urgently needs to be addressed in this field. Summary of the Invention

[0005] The purpose of this application is to provide a device and method for synthesizing and controlling magnetic fields in soil media, which can efficiently and flexibly synthesize and control magnetic fields with specific spatial distribution in soil media.

[0006] To achieve the above objectives, this application provides the following solution: In a first aspect, this application provides a magnetic field synthesis and control device for soil media, comprising: a control unit, a support structure, and multiple magnetic field generating units; Multiple magnetic field generating units are arranged in an optimal spatial layout array in the target soil area via the supporting structure; the supporting structure is used to make the plane in which the multiple magnetic field generating units are located horizontal. All of the aforementioned magnetic field generating units are connected to the control unit; The magnetic field generating unit is used to generate a local magnetic field; The control unit is used to store preset excitation parameter schemes and control multiple magnetic field generating units according to the preset excitation parameter schemes corresponding to each magnetic field generating unit and the multi-level energy management strategy. The optimal spatial layout array and the preset excitation parameter schemes corresponding to each magnetic field generating unit are determined after multi-objective optimization based on finite element simulation and genetic algorithm, with the goal of minimizing the multi-point deviation between the synthetic magnetic field distribution and the expected magnetic field distribution in the target area and maximizing the magnetic field strength and uniformity index of the sub-region.

[0007] Optionally, the magnetic field generating unit specifically includes: an iron core, an inductor coil, and a housing; Both the iron core and the inductor coil are disposed inside the outer casing; The inductor coil is wound around the iron core.

[0008] Optionally, The material of the inductor coil is copper; The outer shell is made of waterproof and insulating material.

[0009] Optionally, the support structure specifically includes: a main frame and multiple adjustable legs; The tops of all of the adjustable legs are connected to the bottom surface of the main frame; The main frame adopts a grid structure; multiple card holders are provided on the main frame; the multiple card holders are arranged in an optimal spatial layout array; each card holder corresponds to a magnetic field generating unit; the card holder is a snap-on fixing structure; the card holder is used to fix the corresponding magnetic field generating unit; the main frame is used to arrange the multiple magnetic field generating units in an optimal spatial layout array. The bottom of each adjustable leg is provided with an extension base and a ground nail hole; the height of the adjustable legs is adjustable; by adjusting the height of multiple adjustable legs, the plane on which multiple magnetic field generating units are located is made horizontal.

[0010] Optionally, the main frame is made of glass fiber reinforced plastic profile; The card holder is made of a non-magnetic material.

[0011] Optionally, the main frame is also provided with multiple attitude adjustment mechanisms; The posture adjustment mechanism is configured in a one-to-one correspondence with the card holder; The posture adjustment mechanism is used to adjust the posture of the corresponding card holder.

[0012] Optionally, the magnetic field synthesis and control device for soil media further includes: a magnetic field sensor network; The magnetic field sensor network is installed within the target soil area; The magnetic field sensor network is connected to the control unit.

[0013] Optionally, the control unit specifically includes: a controller, a power module, a communication module, and multiple power output circuits; The power module, the communication module, and the plurality of power output circuits are all connected to the controller; the communication module is also connected to the magnetic field sensor network; and the plurality of power output circuits are connected one-to-one with the magnetic field generating unit. The control unit is used to store preset excitation parameter schemes and control multiple magnetic field generating units according to the preset excitation parameter schemes corresponding to each magnetic field generating unit based on the power output circuit. The communication module is used to receive signals from the magnetic field sensor network; The control unit is also used to determine the real-time measurement data of the overall magnetic field of the target soil area based on the magnetic field sensor network signal, and to dynamically adjust the excitation parameter scheme of each magnetic field generating unit based on the real-time measurement data of the overall magnetic field and the expected data of the overall magnetic field using a closed-loop control strategy.

[0014] Secondly, this application provides a method for synthesizing and controlling a magnetic field for soil media, the method being applied to the aforementioned magnetic field synthesis and control device for soil media, the method comprising: Based on finite element simulation and genetic algorithm, multi-objective optimization is performed with the goal of minimizing the multi-point deviation between the synthetic magnetic field distribution and the expected magnetic field distribution in the target area, and maximizing the magnetic field strength and uniformity index of the sub-region. The optimal spatial layout array and the preset excitation parameter scheme corresponding to each magnetic field generating unit are determined. After multiple magnetic field generating units are arranged in an optimal spatial layout array, the multiple magnetic field generating units are controlled according to the preset excitation parameter scheme corresponding to each magnetic field generating unit and the multi-level energy management strategy.

[0015] Optionally, the multi-level energy management strategy includes: adaptive current control, zoned rotation power supply technology, field effect synergistic enhancement, and sleep-activation cycle mechanism; The adaptive current control is as follows: based on the real-time measurement data of the overall magnetic field fed back by the magnetic field sensor network, a closed-loop control strategy is adopted to dynamically adjust the current output of each magnetic field generating unit. The partitioned rotating power supply technology is as follows: the optimal spatial layout array is divided into multiple working areas, and high-frequency time-division multiplexing technology is used to rotate the working areas within the time scale. The field effect synergistic enhancement is achieved by minimizing the deviation between the real-time measurement data of the overall magnetic field and the expected value of the overall magnetic field, and solving for the optimal current adjustment based on the least squares method and the Tikhonov regularization method. The hibernation-activation cycle mechanism is as follows: multiple magnetic field generating units are controlled by an intermittent working mode.

[0016] According to the specific embodiments provided in this application, the following technical effects are disclosed: This application provides a device and method for magnetic field synthesis and control in soil media. Existing technologies for applying magnetic fields to soil media suffer from problems such as rapid attenuation, large distortion, difficulty in balancing coverage and uniformity, insufficient penetration depth, difficulty in precisely controlling the field shape, and potential high energy consumption and low efficiency. This device includes multiple discretely arranged magnetic field generating units and a control unit. The magnetic field generating units are arranged in an array according to a spatial layout determined by electromagnetic field finite element simulation and multi-objective genetic algorithm optimization, and distributed in the target soil area. The control unit is configured to independently control the excitation parameters (including current amplitude, phase difference, and frequency) of each magnetic field generating unit, and to drive them collaboratively, so that the local magnetic fields generated by each unit are superimposed and synthesized within the target area to form a predetermined spatially distributed overall magnetic field. This application, through optimized layout and collaborative control, achieves a large-scale (covering a 10m × 10m area), deep-penetrating (depth ≥ 2m), and highly uniform (deviation ≤ ± 5%) magnetic field distribution in soil, applicable to geophysical exploration, heavy metal pollution remediation, and agricultural growth promotion.

[0017] This application proposes a magnetic field synthesis and control method based on an optimized discrete unit array. This method aims to overcome the limitations of single-source or simple combined-source schemes in terms of depth, uniformity, and controllability. It enables efficient and flexible synthesis and control of specific spatially distributed magnetic fields in soil, achieving a large-scale, deep-penetrating, and uniform / controllable magnetic field distribution. By optimizing the discrete unit array layout and coordinating the control of excitation parameters, the method overcomes the strong attenuation and inhomogeneity of the soil medium, synthesizing a more uniformly distributed target magnetic field with required intensity and specific focusing and gradient morphology in a larger area and deeper layers of soil. This significantly improves the depth and distribution quality of the magnetic field. The method offers high flexibility and reconfigurability in magnetic field distribution: the control unit adjusts the excitation of each generating unit in real time and independently, allowing the overall synthesized magnetic field morphology (intensity distribution, main direction, gradient) to be flexibly changed and dynamically adjusted according to application requirements, adapting to different scenarios and task stages. Furthermore, it improves energy utilization efficiency: based on optimized electromagnetic conversion design and intelligent current control strategy, the effective magnetic field area generated per watt of power in this system is 4-6 times that of traditional single-source schemes. In low-power mode, the unit current is only 0.2-0.5A, ensuring energy sustainability for long-term operation. Meanwhile, the zoned rotating power supply technology allows the entire system to be powered by solar energy or a battery system, greatly expanding application scenarios. Compared to traditional high-power single-source solutions that consume hundreds of watts, this application reduces energy consumption by 70-85% for equivalent performance. Enhanced system robustness and scalability: The distributed structure of discrete units improves the system's fault tolerance; a single unit failure can be partially compensated by adjusting the excitation parameters of other units. Simultaneously, the system is easily modularly expanded and adjusted. Better addressing the unique challenges of soil media applications: This application fully considers the complexity of the soil environment and, through optimized design and feedback calibration mechanisms, better adapts to the uncertainty and spatiotemporal variations of soil parameters, achieving a more stable and reliable magnetic field application. Through a closed-loop calibration mechanism based on the sensitivity matrix, the magnetic field distribution deviation is controlled within ±5%. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a magnetic field synthesis and control device for soil media in one embodiment of this application.

[0020] Figure 2 This is a top view of the discrete magnetic field generating unit matrix array layout in one embodiment of this application.

[0021] Figure 3 This is a cross-sectional view of the magnetic field generating unit in one embodiment of this application.

[0022] Figure 4 This is a block diagram of the internal functional modules of the control unit and its connection with the sensor network in one embodiment of this application.

[0023] Reference numerals: 1-Magnetic field generating unit; 2-Control unit; 3-Supporting structure; 4-Target soil area; 5-Iron core; 6-Shell; 7-Coil; 8-Connection terminal; 9-Power module; 10-Controller; 11-Communication interface; 12-Power output circuit; 13-Magnetic field sensor network; 14-Signal transmission cable. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] In one exemplary embodiment, such as Figure 1 As shown, a magnetic field synthesis and control device for soil media is provided, including: a control unit 2, a support structure 3, and multiple magnetic field generating units 1; the multiple magnetic field generating units are arranged in an optimal spatial layout array in a target soil region 4 through the support structure; the support structure is used to make the plane where the multiple magnetic field generating units are located horizontal; the multiple magnetic field generating units are all connected to the control unit; the magnetic field generating units are used to generate local magnetic fields; the control unit is used to store preset excitation parameter schemes, and control the multiple magnetic field generating units according to the preset excitation parameter schemes corresponding to each magnetic field generating unit and a multi-level energy management strategy; the optimal spatial layout array and the preset excitation parameter schemes corresponding to each magnetic field generating unit are determined after multi-objective optimization based on finite element simulation and genetic algorithm, with the goal of minimizing the multi-point deviation between the synthesized magnetic field distribution and the expected magnetic field distribution in the target region, and maximizing the magnetic field strength and uniformity index of the sub-region. Figure 1 In this context, d represents the unit spacing, and h represents the burial depth.

[0027] The magnetic field synthesis and control device for soil media includes multiple discretely arranged magnetic field generating units, each capable of generating a local magnetic field; and a control unit connected to each magnetic field generating unit and capable of independently controlling its excitation parameters. The excitation parameters include current amplitude, phase, frequency, on / off timing, and duty cycle, used to control the magnetic field characteristics generated by the magnetic field generating units. Each magnetic field generating unit is arranged in an array according to a spatial layout determined based on the target magnetic field distribution and the electromagnetic parameters of the soil (its conductivity σ, relative permeability μr spatial distribution and layered structure data), and distributed in the target soil region 4. Figure 2 As shown, the basic configuration is a 3×3 matrix array layout (9 units), and the unit spacing d can be adjusted according to specific application requirements. The control unit 2 is connected to each of the magnetic field generating units 1 via signal transmission cables 14. The control unit collaboratively drives each magnetic field generating unit according to the optimized excitation parameter scheme, so that the local magnetic fields generated by them are superimposed and synthesized in the target soil area to form an overall magnetic field with a predetermined spatial distribution.

[0028] The magnetic field generating unit specifically includes: an iron core 5, an inductor coil 7, and a housing 6; both the iron core and the inductor coil are housed within the housing; the inductor coil is wound around the iron core. The magnetic field generating unit is connected to the control unit via a connection terminal 8; the inductor coil is made of copper; the housing is made of waterproof insulating material. The magnetic field generating unit is an inductor coil structure integrating a high-permeability iron core, and the coil has a cross-sectional area of ​​1.5 mm². 2 The inductor is constructed by winding 500 turns of copper material and encapsulating it within a waterproof and insulating shell with a high protection rating of IP68. The iron core 5 is made of a high-permeability material, cylindrical in shape, with a diameter of 8 cm and a length of 20 cm. The iron core 5 is composed of stacked, mutually insulating thin sheets, and its surface is treated with phosphating and an insulating varnish to reduce eddy current losses during high-frequency operation. The inductor coil 7 has a cross-sectional area of ​​1.5 mm². 2 The insulated copper wire is wound 500 turns around the outside of the iron core 5, generating an inductance of approximately 30mH under the target current. The coil 7 and the iron core 5 are entirely encapsulated within a waterproof insulating shell 6 made of epoxy resin, with a protection rating of IP68. The shell 6 is equipped with connection terminals 8 for secure connection to the signal transmission cable 14. Figure 3 As shown, the magnetic field generating unit 1 is an inductor coil 7 unit with an iron core 5. The support structure 3 is used to precisely fix multiple magnetic field generating units 1 according to the optimized spatial design. The support structure 3 is made of high-strength glass fiber reinforced plastic profile, and its influence on the magnetic field is negligible. The support structure 3 adopts a modular frame design, including a main frame and an adjustable support leg system. The main frame is equipped with standardized brackets for precisely fixing the magnetic field generating units 1.

[0029] For agricultural growth-promoting applications and environmental remediation scenarios requiring long-term continuous operation, this application provides optimized design parameters: for applications requiring only a weak magnetic field strength of 0–100 mT, the operating current is set to 0.2 A–0.5 A, and the coil conductor cross-sectional area is 1.0 mm². 2 The core length is 25cm, ensuring that the system can maintain the required magnetic field penetration depth and spatial distribution parameters even in ultra-low current operating mode. This application utilizes a highly efficient electromagnetic conversion design, enabling a magnetic field strength of approximately 10mT-20mT to be generated per 0.1A current, far superior to traditional designs and significantly reducing energy consumption. Preferably, the multiple magnetic field generating units are fixed in a preset array form (matrix array, ring array, and three-dimensional array) by a non-magnetic support structure. The optimized spatial layout aims to ensure that the synthesized overall magnetic field meets specific uniformity and focusing parameters within the target area.

[0030] The supporting structure specifically includes: a main frame and multiple adjustable legs; the tops of the adjustable legs are connected to the bottom of the main frame; the main frame adopts a grid structure; multiple mounting brackets are provided on the main frame; the mounting brackets are arranged in an optimal spatial layout array; each mounting bracket corresponds to a magnetic field generating unit; the mounting brackets are snap-fit ​​fixing structures; the mounting brackets are used to fix the corresponding magnetic field generating units; the main frame is used to arrange the multiple magnetic field generating units in an optimal spatial layout array; the bottom of each adjustable leg is provided with an extension base and ground nail holes; the height of the adjustable legs is adjustable; by adjusting the height of the multiple adjustable legs, the plane on which the multiple magnetic field generating units are located is made horizontal. The main frame is made of fiberglass reinforced plastic profile; the mounting brackets are made of non-magnetic material. The main frame also has multiple attitude adjustment mechanisms; each attitude adjustment mechanism corresponds to a mounting bracket; the attitude adjustment mechanisms are used to adjust the attitude of the corresponding mounting bracket.

[0031] The support structure employs a modular frame design, comprising a main frame and an adjustable support system. The main frame utilizes a high-strength glass fiber reinforced plastic profile to construct a grid structure, with each grid unit featuring a standardized mounting bracket for precise fixation of the magnetic field generating unit. The brackets employ a snap-fit ​​design, ensuring unit positioning accuracy and stability while facilitating installation and disassembly. The frame base is equipped with height-adjustable legs to adapt to uneven terrain and ensure overall array levelness. The bases of the legs feature extended bases and ground anchor holes to enhance system stability on soft soil surfaces. The connection between the magnetic field generating unit and the support structure utilizes a snap-fit ​​fixing mechanism made of non-magnetic material (nylon). These fixing mechanisms ensure the magnetic field generating unit is securely installed in the predetermined position without interfering with the magnetic field distribution. For applications requiring precise control of the magnetic field direction, the mounting brackets are equipped with a simple adjustment mechanism, allowing for fine-tuning within a ±5° range.

[0032] The magnetic field synthesis and control device for soil media provided in this embodiment further includes: a magnetic field sensor network; the magnetic field sensor network is disposed within the target soil area; and the magnetic field sensor network is connected to the control unit. The magnetic field sensor network consists of multiple triaxial fluxgate sensor nodes, which communicate with the control unit via the LoRaWAN 1.0.3 wireless protocol. Each sensor node is arranged according to a predetermined grid on the surface or at a specific depth of the target area to acquire real-time data on the magnetic field distribution within the target area.

[0033] The control unit specifically includes: a controller 10, a power supply module 9, a communication module 11, and multiple power output circuits 12; the power supply module, the communication module, and the multiple power output circuits are all connected to the controller; the communication module is also connected to the magnetic field sensor network; the multiple power output circuits are connected one-to-one with the magnetic field generating units; the control unit is used to store preset excitation parameter schemes, and controls multiple magnetic field generating units according to the preset excitation parameter schemes corresponding to each magnetic field generating unit based on the power output circuits; the communication module is used to receive signals from the magnetic field sensor network; the control unit is also used to determine the overall real-time measurement data of the magnetic field of the target soil area based on the magnetic field sensor network signals, and dynamically adjust the excitation parameter scheme of each magnetic field generating unit using a closed-loop control strategy based on the overall real-time measurement data of the magnetic field and the expected data of the overall magnetic field.

[0034] The core component of the control unit has the ability to store preset excitation parameter schemes and can adjust the excitation parameters in real time based on feedback signals from the magnetic field sensor (a wireless magnetic field sensor network composed of multiple triaxial fluxgate sensor nodes connected via the LoRaWAN 1.0.3 wireless protocol) using a least squares method based on the sensitivity matrix. For example... Figure 4 As shown, the control unit 2 includes a power module 9, a controller core 10, a communication interface 11, and a power output circuit 12. The power module 9 provides independent power output to each magnetic field generating unit 1 through the power output circuit 12, employing a multi-level current control strategy according to application requirements: a low-power mode (0.2A-0.5A) is suitable for long-term applications with weak magnetic fields (0-100mT) such as agricultural growth promotion or environmental remediation; a high-intensity mode (1A-2A) is only used for short-term, high magnetic field intensity (>100mT) applications such as geophysical exploration. The operating frequency is adjustable within the range of 1Hz-10kHz. The controller core 10 adopts a heterogeneous computing architecture composed of a microprocessor (MPU) main control unit and a digital signal processor (DSP) co-processing unit, possessing the ability to store preset excitation parameter schemes and independently control the excitation parameters of each magnetic field generating unit 1, including current amplitude, phase difference, and frequency. The communication interface 11 supports wireless communication with the magnetic field sensor network 13, enabling data transmission and remote control.

[0035] In an exemplary embodiment, a method for synthesizing and controlling a magnetic field in a soil medium is provided. The method is applied to the aforementioned magnetic field synthesis and control device for soil media, and includes: Step 1: Based on finite element simulation and genetic algorithm, multi-objective optimization is performed with the goal of minimizing the multi-point deviation between the synthetic magnetic field distribution and the expected magnetic field distribution in the target area, and maximizing the magnetic field strength and uniformity index of the sub-region, to determine the optimal spatial layout array and the preset excitation parameter scheme corresponding to each magnetic field generating unit. Step 2: After arranging multiple magnetic field generating units in an optimal spatial layout array, control the multiple magnetic field generating units according to the preset excitation parameter scheme corresponding to each magnetic field generating unit and a multi-level energy management strategy. The multi-level energy management strategy includes: adaptive current control, zoned rotating power supply technology, field effect synergistic enhancement, and a sleep-activation cycle mechanism; adaptive current control is: dynamically adjusting the current output of each magnetic field generating unit based on the real-time measurement data of the overall magnetic field fed back by the magnetic field sensor network using a closed-loop control strategy; zoned rotating power supply technology is: dividing the optimal spatial layout array into multiple working areas, and using high-frequency time-division multiplexing technology to rotate the operation of each working area within a time scale; field effect synergistic enhancement is: aiming to minimize the deviation between the real-time measurement data of the overall magnetic field and the expected value of the overall magnetic field, solving for the optimal current adjustment amount based on the least squares method and the Tikhonov regularization method; the sleep-activation cycle mechanism is: controlling multiple magnetic field generating units using an intermittent working mode.

[0036] This application also provides a corresponding magnetic field synthesis and control method, which uses the aforementioned device to generate a magnetic field with a predetermined spatial distribution in a target soil area, mainly including the following steps.

[0037] (a) Data Acquisition and Optimization Design: Based on the target area, the three-dimensional electromagnetic property parameter model of the soil acquired and constructed through electromagnetic induction, and the expected magnetic field distribution requirements, multi-objective optimization was performed using numerical simulation calculation based on the finite element method (FEM) and genetic algorithm (GA). (Specific optimization parameters were: population size 150, iteration count 500; the optimization objective function was defined as minimizing the root mean square error (RMSE) between the synthesized magnetic field and the expected distribution, while setting the upper limit of single-path excitation current and the upper limit of total power consumption as constraints). When the population size was 150 and the number of iterations was 500, the algorithm converged to a global optimum with an error of less than 5%. This optimization determined the spatial layout of the magnetic field generating unit array and the excitation parameter set for the collaborative operation of each unit. The core objective of the optimization algorithm was to minimize the multi-point deviation between the synthesized magnetic field distribution and the expected magnetic field distribution within the target area, while maximizing the magnetic field strength and specific uniformity index of a specific sub-region.

[0038] (b) Deployment and connection: According to the optimized spatial layout, multiple magnetic field generating units are accurately arranged in the target soil area and a reliable electrical connection is established between them and the control unit.

[0039] (c) Coordinated Excitation and Field Synthesis: The control unit independently and collaboratively outputs precisely controlled excitation signals to each magnetic field generating unit based on the optimized excitation parameter set. A multi-level current control strategy is adopted according to application requirements and energy efficiency targets: a low-power mode (0.2A-0.5A) is suitable for long-term operation in weak magnetic fields (0-100mT); a high-intensity mode (1A-2A) is only used for short-term applications requiring stronger magnetic fields (>100mT). A soft-start method is used to gradually load the excitation to reduce instantaneous current surges and extend system lifespan. The local magnetic fields generated by each unit are superimposed and synthesized within the target soil area to form a predetermined spatially distributed overall magnetic field. For applications requiring high-precision magnetic field control, the system monitors and adjusts the excitation parameters of each unit in real time to ensure that the magnetic field distribution continuously meets requirements.

[0040] (d) Feedback Calibration: Real-time magnetic field measurement data within the target area is acquired. The control unit dynamically adjusts the excitation parameters of each magnetic field generating unit based on the deviation between the measured data and the expected distribution to perform calibration, thereby improving the accuracy and stability of the magnetic field distribution. The measured magnetic field data is acquired through a network of magnetic field sensors pre-installed within the target area. Based on the received real-time sensor data, the control unit dynamically adjusts the excitation parameters of each magnetic field generating unit using a least squares method based on the sensitivity matrix.

[0041] The synthesized magnetic field is an alternating magnetic field (frequency from 1Hz to 10kHz). The control unit precisely controls the phase difference of the excitation current of each magnetic field generating unit to form a magnetic field distribution with specific directionality, rotation characteristics and focusing characteristics in the target area; or it is a pulsed magnetic field / DC magnetic field. The control unit controls the on / off timing, duty cycle and current amplitude of each magnetic field generating unit to achieve rapid enhancement of the magnetic field in the target area, specific time series changes and specific shape maintenance.

[0042] When a rotating magnetic field is needed to promote root growth in a specific direction or enhance electromagnetic induction signals in the soil, it is achieved through multi-unit phase coordinated control. Specifically, the magnetic field generating units are grouped in a ring or matrix configuration, providing each group with an alternating current of the same frequency but with a precise phase difference. For example, in a typical configuration, the first group has a phase of 0°, the second 90°, the third 180°, and the fourth 270°. The resulting magnetic field exhibits rotational characteristics. The phase precision control module of the control unit provides 0.1° resolution, ensuring smoothness and accuracy of rotation. A magnetic field sensor network monitors the actual performance of the rotating magnetic field in real time, and the control system dynamically fine-tunes the phase and amplitude of each magnetic field generating unit to ensure rotational stability. The number and spatial layout of the discrete magnetic field generating units are modular, allowing expansion or adjustment (from a 3×3 array to a 5×5 array) according to the target area size and application requirements. When the number or layout of units changes, the excitation parameter set is updated by re-executing the optimization design in step (a) to maintain or achieve a new predetermined spatial magnetic field distribution.

[0043] The modular expansion mechanism is mainly achieved through the following technologies: (i) Standardized unit design: All magnetic field generating units adopt standardized design and interfaces, making them universal in arrays of different sizes and shapes; (ii) Scalable support structure: The support structure adopts a modular design, achieving physical expansion by adding edge frame segments and connecting additional support modules. A 3×3 matrix array can be expanded to a 5×5 array via edge connectors without rebuilding the entire support system; (iii) Distributed control architecture: The control unit adopts a master-slave hierarchical design, enabling dynamic addition of control channels. The basic control unit manages one magnetic field generating unit, and the control capability can be expanded to 25 magnetic field generating units by adding expansion modules; (iv) Intelligent cable management system: Modular cable management components and digital addressing technology are used to effectively handle the signal transmission needs of a large number of units. The system adopts a bus-type communication protocol and a multi-level hub design to avoid wiring complexity and signal interference problems caused by the increase in the number of cables; (v) Adaptive optimization algorithm: When the system scale expands or the configuration changes, the control system automatically initiates a re-optimization process, generating a new optimal set of excitation parameters based on the updated system configuration and soil parameter model.

[0044] In the optimization design phase: based on the target area, soil electromagnetic parameter model, and expected magnetic field distribution requirements, numerical simulation calculations were performed using the finite element method, combined with a genetic algorithm for multi-objective optimization, to determine the spatial layout of the magnetic field generating unit array 1 and the excitation parameter set driving the coordinated operation of each unit. The genetic algorithm employed simulated binary crossover and polynomial mutation, with a crossover probability of 0.8, a mutation probability of 0.01, and a tournament selection pressure of 2. The optimization objective function was defined as minimizing the root mean square error between the synthesized magnetic field and the expected distribution, while setting upper limits for single-path excitation current and total power consumption as constraints.

[0045] Deployment and Connection Phase: Following the optimized spatial layout, multiple magnetic field generating units are installed on the supporting structure and positioned in the target soil area. Each magnetic field generating unit is reliably connected to the power output circuit of the control unit via signal transmission cables. Simultaneously, the various sensor nodes of the magnetic field sensor network are deployed.

[0046] Synergistic Excitation and Field Synthesis Stage: Based on the optimized excitation parameter set, the control unit outputs precisely controlled excitation signals to each magnetic field generating unit via the power output circuit. The system intelligently selects the most suitable current operating mode according to application requirements and target magnetic field strength. The system employs a soft-start method to gradually apply excitation, reducing instantaneous current surges. The local magnetic fields generated by each magnetic field generating unit are superimposed and synthesized within the target soil area to form a predetermined spatially distributed overall magnetic field.

[0047] Feedback calibration phase: The magnetic field sensor network collects and transmits magnetic field data within the target area to the control unit in real time. The controller core compares the measured magnetic field distribution with the target magnetic field distribution. If the deviation exceeds a set threshold, a calibration algorithm is initiated to adjust the excitation parameters of each magnetic field generating unit 1 until the deviation meets the accuracy requirements. This step effectively compensates for the effects of model errors, deployment errors, and environmental changes.

[0048] This feedback calibration mechanism is the core approach of this application to address the transient changes in soil electromagnetic parameters (especially conductivity σ and relative permeability μr) as described in the background art, thereby overcoming the resulting large deviations in magnetic field distribution (e.g., up to 40%). Specifically: when changes in soil moisture content, mineral composition, and other factors cause dynamic changes in soil electromagnetic parameters, a magnetic field sensor network pre-installed in the target area captures the resulting deviation ΔB in the synthetic magnetic field distribution in real time. The controller core of the control unit continuously compares this deviation with a preset threshold (e.g., ±5% of the target accuracy). Once the deviation exceeds the limit, the calibration algorithm is triggered. This algorithm utilizes a pre-calculated or real-time updated sensitivity matrix S based on the current soil parameter model, and solves a Tikhonov regularized least squares problem (specifically, the formula is...). This allows for the rapid calculation of the required adjustment amount Δ of the excitation parameters (mainly current amplitude and / or phase) for each magnetic field generating unit. I For gradual changes in soil conductivity σ within a range of ±10%, this calibration process can typically be completed within 1-3 iterations (corresponding to a response time of approximately 5 seconds), restoring the uniformity of the magnetic field distribution or its fit with the target distribution to within the design specifications. If soil parameters undergo drastic abrupt changes (e.g., a sudden increase in soil moisture content due to heavy rainfall or concentrated irrigation, causing conductivity σ to surge from 0.03 S / m to 0.045 S / m in a short period), significantly reducing the applicability of the current sensitivity matrix S (e.g., when the system detects changes in soil conductivity σ exceeding the preset effective range of the current sensitivity matrix calibration, or when changes in the ferromagnetic mineral content in the soil cause the relative permeability μr to significantly exceed 1.2), the control unit will trigger a rapid reassessment or update process for the sensitivity matrix S. Even in this case, the entire re-optimization and parameter adjustment process can typically be completed within, for example, 10 seconds, ensuring that the magnetic field distribution quickly recovers and stabilizes within the target requirements. Therefore, through this closed-loop feedback calibration mechanism that includes real-time monitoring, deviation assessment, rapid parameter inversion based on the sensitivity matrix, and, when necessary, self-updating of the sensitivity matrix, the magnetic field distribution deviation, which may be caused by transient changes in soil parameters, by more than 40%, can be effectively and stably controlled within an accuracy range of ±5%.

[0049] For applications requiring different magnetic field configurations, this application can generate and switch between various field types via the control unit 2: When a uniform magnetic field is needed, the control unit coordinates the excitation parameters of each magnetic field generating unit, appropriately increasing the current of the edge units to compensate for edge effects and forming a uniformly distributed magnetic field within the target area. When a gradient magnetic field is needed, the control unit adjusts the excitation current amplitude of each unit according to the spatial gradient, while setting an appropriate phase difference to form a stable magnetic field gradient in the target direction. When a focused magnetic field is needed, the control unit makes the excitation current amplitude of each unit inversely proportional to its distance from the target point, while setting the phase according to the distance, so that the magnetic field forms an intensity peak at the target location. When a rotating magnetic field is needed, the control unit groups the units and provides each group with an alternating current of the same frequency but with a precise phase difference, forming the rotational characteristics of the overall magnetic field.

[0050] The number and spatial layout of the magnetic field generating units in this application are modular, allowing for expansion or adjustment based on the target area size and application requirements. For example, when the array needs to be expanded from a basic 3×3 configuration to a 5×5 configuration to cover a larger target area, the initial spatial layout of the newly added magnetic field generating units typically refers to the geometric characteristics of the original optimized array (e.g., maintaining the optimized unit spacing d and expanding outwards in a similar grid or ring pattern), or is pre-optimized based on the specific needs of the new, larger target area. The key excitation parameter re-optimization process demonstrates the efficiency of incremental optimization. Specifically, the adaptive optimization algorithm of the control unit (based on FEM and GA multi-objective optimization) does not start the search from a completely random state when processing the expanded 5×5 array. Instead, it automatically calls upon and utilizes the set of excitation parameters (i.e., historical optimization data) of each unit that has been optimized under similar soil conditions in the original 3×3 array and performs well, using it as historical data for the new round of genetic algorithm (GA). Specifically, firstly, statistical analysis is performed on the excitation parameters (e.g., current amplitude and phase) of each unit in a set of excellent solutions obtained from the original 3×3 array under similar soil conditions, extracting key statistical characteristics such as mean, standard deviation, and effective value range. Secondly, when generating the initial population containing all 25 unit excitation parameters for the 5×5 array GA, a broad, completely uniform random initialization is no longer used. Instead, adjustments are made based on the aforementioned statistical characteristics: for example, the center (mean) of the random generation of new parameters is set to approach the mean of parameters observed in the 3×3 array, and the range of its random generation is appropriately narrowed to make it more concentrated within the effective parameter range observed in the 3×3 array; it is even possible to attempt to simulate the parameter distribution characteristics observed in the 3×3 array (such as Gaussian distribution) for non-uniform random initialization. For units in the 5×5 array corresponding to the positions in the original 3×3 array, their parameter initialization can be more inclined towards historical data, while newly added units can retain greater exploration freedom while referencing historical statistical ranges. By adjusting the initialization strategy based on historical data, the individuals in the initial population are more likely to possess parameter characteristics close to the optimal solution from the outset. This significantly reduces the algorithm's early exploration in inefficient parameter regions and accelerates convergence towards the optimal solution for the 5×5 array. A high-quality initial population is a key component, or serves as heuristic information to guide its generation. Through this incremental optimization strategy, which leverages existing knowledge and historical data to guide the search direction, the algorithm significantly reduces blind exploration in a vast parameter space, thus converging more quickly to the globally or near-globally optimal set of excitation parameters for the expanded 5×5 array. Practice shows that compared to optimizing a 5×5 array from scratch (i.e., using a purely random initial population), this incremental optimization method can effectively reduce the computation time or number of iterations by approximately 60% while achieving the same optimization target accuracy (e.g., the root mean square error (RMSE) of the synthesized magnetic field compared to the expected distribution is less than 5%), thereby significantly improving the response speed and deployment efficiency after system configuration changes.

[0051] To adapt to the energy conditions of different application scenarios, this application implements a multi-level energy management strategy, including: 1. Adaptive current control: The system dynamically adjusts the current output of each unit based on real-time magnetic field strength feedback, so that the actual working current is usually only 60%-80% of the set value, thus maximizing energy saving while ensuring the magnetic field effect.

[0052] 2. Zoned Rotational Power Supply Technology: Especially for 5×5 array configurations, the system divides the array into 3-5 working zones, employing high-frequency time-division multiplexing technology (>500Hz). Each zone rotates in operation within a time scale, achieving an equivalent continuous magnetic field distribution while reducing instantaneous power consumption by 60%-80%. This technology enables even large-scale arrays of 25 units to be powered by solar energy or battery systems, meeting the application needs of areas far from the power grid.

[0053] 3. Synergistic Enhancement of Field Effects: By precisely controlling the phase relationship of the magnetic fields of each unit, this application achieves synergistic enhancement of field effects, resulting in a 15%-30% higher actual combined magnetic field strength than simple superposition, further reducing current requirements. Synergistic enhancement of field effects is based on the principle of electromagnetic field vector superposition. This is achieved by precisely controlling the phase difference of the excitation current in each unit. ϕ i Optimize the magnetic field component B generated by each unit at the target point. i The relative phase relationship makes the synthesized magnetic field B total =∑( B i ⋅e jϕi The amplitude of the phase difference is maximized. When the phases of each element are optimally configured, the combined magnetic field strength at the target point can be increased by 15%-30% (i.e., 1.15-1.30 times) compared to the combined field strength when each element is driven in phase. This effect of maximizing constructive interference through phase optimization has been verified by finite element simulation and small-scale experiments. ϕi The objective function was solved using a particle swarm optimization algorithm with 20 particles, a maximum of 100 iterations, an inertia weight of 0.7, an individual learning factor of 1.5, and a swarm learning factor of 2.0. .

[0054] Where i represents a magnetic field generating unit, N is the total number of magnetic field generating units in the system; p represents a monitoring point, and M is the total number of monitoring points; The calculated magnetic field strength value generated by the i-th magnetic field generating unit at the p-th monitoring point is expressed in mT. Let be the desired target magnetic field strength value at the p-th monitoring point, in mT. The convergence condition of the objective function is that the change in field strength gain over 10 consecutive iterations is <0.5%.

[0055] During sensitivity matrix calibration, the current adjustment is calculated using the following formula: .

[0056] in, S is the current adjustment vector, representing the amount of current that needs to be adjusted for each magnetic field generating unit, in A; S represents the sensitivity matrix, representing the sensitivity relationship of the magnetic field at the monitoring point to the current changes of each unit, in mT / A; Sᵀ is the transpose of the sensitivity matrix S. The magnetic field deviation vector represents the difference between the measured magnetic field value and the target value at each monitoring point, with the unit being mT.

[0057] This formula is based on the least squares method, obtaining the optimal current adjustment by solving the normal equations, so that the adjusted magnetic field distribution is closest to the target distribution. In practical operation, to avoid ill-conditioned problems, the system uses the Tikhonov regularization method to improve the stability of the solution.

[0058] 4. Dormancy-Activation Cycle Mechanism: For agricultural and environmental applications, the system can adopt an intermittent working mode, such as working for 15 minutes per hour, reducing energy consumption by more than 75% while maintaining biological effects.

[0059] Theoretical calculations show that for typical farmland growth-promoting applications (magnetic field strength of 25 mT), the total power consumption of a basic 3×3 array configuration (9 units) can be controlled within the range of 30-45W, far lower than the 150-300W power consumption of traditional single-coil schemes. When using a 5×5 array (25 units) with a zone rotation technique, only about 1 / 3 of the units (8-9 units) are active at any given time. Based on 0.5A×24V per unit, the peak power consumption is approximately 108W. Considering the synergistic enhancement of the field effect (efficiency improvement of 25%), the actual power consumption drops to approximately 60W. Compared to traditional single-coil methods, the magnetic field synthesis and control technology of this application can achieve a uniform magnetic field distribution over a larger area and at a deeper level. Through optimized discrete unit array layout and synergistic control strategies, it solves the problems of insufficient penetration depth, poor uniformity, and weak controllability faced by traditional technologies when applying magnetic fields to soil media, providing a new technical solution for fields such as geophysical exploration, in-situ soil remediation, and precision agriculture.

[0060] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0061] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A magnetic field synthesis and control device for soil media, characterized in that, include: Control unit, support structure and multiple magnetic field generating units; Multiple magnetic field generating units are arranged in an optimal spatial layout array in the target soil area via the supporting structure; The supporting structure is used to make the plane containing the plurality of magnetic field generating units horizontal; All of the aforementioned magnetic field generating units are connected to the control unit; The magnetic field generating unit is used to generate a local magnetic field; The control unit is used to store preset excitation parameter schemes and control multiple magnetic field generating units according to the preset excitation parameter schemes corresponding to each magnetic field generating unit and the multi-level energy management strategy. The optimal spatial layout array and the preset excitation parameter schemes corresponding to each magnetic field generating unit are determined after multi-objective optimization based on finite element simulation and genetic algorithm, with the goal of minimizing the multi-point deviation between the synthetic magnetic field distribution and the expected magnetic field distribution in the target area and maximizing the magnetic field strength and uniformity index of the sub-region.

2. The magnetic field synthesis and control device for soil media according to claim 1, characterized in that, The magnetic field generating unit specifically includes: an iron core, an inductor coil, and a housing; Both the iron core and the inductor coil are disposed inside the outer casing; The inductor coil is wound around the iron core.

3. The magnetic field synthesis and control device for soil media according to claim 2, characterized in that, The material of the inductor coil is copper; The outer shell is made of waterproof and insulating material.

4. The magnetic field synthesis and control device for soil media according to claim 1, characterized in that, The supporting structure specifically includes: a main frame and multiple adjustable legs; The tops of all of the adjustable legs are connected to the bottom surface of the main frame; The main frame adopts a grid structure; multiple card holders are provided on the main frame; the multiple card holders are arranged in an optimal spatial layout array; each card holder corresponds to a magnetic field generating unit; the card holder is a snap-on fixing structure; the card holder is used to fix the corresponding magnetic field generating unit; the main frame is used to arrange the multiple magnetic field generating units in an optimal spatial layout array. The bottom of each adjustable leg is provided with an extension base and a ground nail hole; the height of the adjustable legs is adjustable; by adjusting the height of multiple adjustable legs, the plane on which multiple magnetic field generating units are located is made horizontal.

5. The magnetic field synthesis and control device for soil media according to claim 4, characterized in that, The main frame is made of glass fiber reinforced plastic profile; The card holder is made of a non-magnetic material.

6. The magnetic field synthesis and control device for soil media according to claim 4, characterized in that, The main frame is also equipped with multiple attitude adjustment mechanisms; The posture adjustment mechanism is configured in a one-to-one correspondence with the card holder; The posture adjustment mechanism is used to adjust the posture of the corresponding card holder.

7. The magnetic field synthesis and control device for soil media according to claim 1, characterized in that, The magnetic field synthesis and control device for soil media further includes: a magnetic field sensor network; The magnetic field sensor network is installed within the target soil area; The magnetic field sensor network is connected to the control unit.

8. The magnetic field synthesis and control device for soil media according to claim 7, characterized in that, The control unit specifically includes: a controller, a power module, a communication module, and multiple power output circuits; The power module, the communication module, and the plurality of power output circuits are all connected to the controller; the communication module is also connected to the magnetic field sensor network; and the plurality of power output circuits are connected one-to-one with the magnetic field generating unit. The control unit is used to store preset excitation parameter schemes and control multiple magnetic field generating units according to the preset excitation parameter schemes corresponding to each magnetic field generating unit based on the power output circuit. The communication module is used to receive signals from the magnetic field sensor network; The control unit is also used to determine the real-time measurement data of the overall magnetic field of the target soil area based on the magnetic field sensor network signal, and to dynamically adjust the excitation parameter scheme of each magnetic field generating unit based on the real-time measurement data of the overall magnetic field and the expected data of the overall magnetic field using a closed-loop control strategy.

9. A method for synthesizing and controlling a magnetic field in soil media, characterized in that, The method is applied to the magnetic field synthesis and control device for soil media as described in any one of claims 1-8, the method comprising: Based on finite element simulation and genetic algorithm, multi-objective optimization is performed with the goal of minimizing the multi-point deviation between the synthetic magnetic field distribution and the expected magnetic field distribution in the target area, and maximizing the magnetic field strength and uniformity index of the sub-region. The optimal spatial layout array and the preset excitation parameter scheme corresponding to each magnetic field generating unit are determined. After multiple magnetic field generating units are arranged in an optimal spatial layout array, the multiple magnetic field generating units are controlled according to the preset excitation parameter scheme corresponding to each magnetic field generating unit and the multi-level energy management strategy.

10. The method for synthesizing and controlling a magnetic field for soil media according to claim 9, characterized in that, The multi-level energy management strategy includes: adaptive current control, zoned rotational power supply technology, field effect synergistic enhancement, and a sleep-activation cycle mechanism; The adaptive current control is as follows: based on the real-time measurement data of the overall magnetic field fed back by the magnetic field sensor network, a closed-loop control strategy is adopted to dynamically adjust the current output of each magnetic field generating unit. The partitioned rotating power supply technology is as follows: the optimal spatial layout array is divided into multiple working areas, and high-frequency time-division multiplexing technology is used to rotate the working areas within the time scale. The field effect synergistic enhancement is achieved by minimizing the deviation between the real-time measurement data of the overall magnetic field and the expected value of the overall magnetic field, and solving for the optimal current adjustment based on the least squares method and the Tikhonov regularization method. The hibernation-activation cycle mechanism is as follows: multiple magnetic field generating units are controlled by an intermittent working mode.

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