A Demagnetization Method, Device, Computer Equipment and Storage Medium for a Magnetic Shielding Cabin

Abstract

The present invention relates to the technical fields of magnetic shielding cabins and degaussing, and discloses a degaussing method, device, computer device and storage medium for a magnetic shielding cabin. The degaussing method includes: applying a saturation current to the degaussing coil of the magnetic shielding cabin to pre-magnetize the magnetic shielding cabin to a magnetically saturated state; applying a phased decaying oscillating current to the degaussing coil of the magnetic shielding cabin to gradually reduce the magnetization degree of the magnetic shielding cabin; monitoring the magnetization degree of the magnetic shielding cabin in real time, and dynamically adjusting the parameters of current decay through a closed-loop feedback mechanism until the magnetization degree of the magnetic shielding cabin meets the target requirements. Through the synergistic effect of the phased demagnetization strategy and the closed-loop feedback mechanism, efficient and precise degaussing of multi-layer permalloy materials in a large magnetic shielding cabin is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic shielding cabins and degaussing technologies, and particularly to a degaussing method, device, computer device and storage medium for a magnetic shielding cabin. Background Art

[0002] A magnetic shielding cabin is a core device for shielding external magnetic field interference. It has a wide range of applications in fields that require high-precision magnetic field control, such as magnetic field measurement, magnetoencephalogram (ME / CG) experiments, and geomagnetic field research. Degaussing can reduce the residual magnetic field and magnetic noise of the cabin body, thereby creating a more stable magnetic field environment. Its degaussing process aims to reduce the remanent magnetism and magnetic noise in the cabin to an extremely low level to ensure the high stability and weakness of the magnetic field in the experimental environment.

[0003] Traditional autotransformer-type degaussing equipment relies on the manual method of increasing the current, and cannot achieve precise current control and automatic adjustment, resulting in poor repeatability and low precision in the degaussing process. Especially when it is necessary to reduce the remanent magnetism of a relatively large magnetic shielding cabin (9m³ < V < 100m³) from hundreds of nanoteslas to below 10nT, manual degaussing is difficult to meet the degaussing requirements. Moreover, the degaussing coils of large magnetic shielding cabins usually have the characteristics of high impedance (Rs > 3Ω) and high inductance (Ls > 100mH), which require extremely high output power and current precision of the degaussing power supply. Existing degaussing equipment is difficult to stably provide the required high-precision current output. Summary of the Invention

[0004] In view of this, the present invention provides a degaussing method, device, computer device and storage medium for a magnetic shielding cabin to solve the problem that traditional autotransformer-type degaussing equipment relies on the manual method of increasing the current and cannot achieve precise current control and automatic adjustment.

[0005] In a first aspect, the present invention provides a degaussing method for a magnetic shielding cabin, the method comprising:

[0006] Applying a saturation current to the degaussing coil of the magnetic shielding cabin to pre-magnetize the magnetic shielding cabin to a magnetically saturated state;

[0007] Applying a phased decaying oscillating current to the degaussing coil of the magnetic shielding cabin to gradually reduce the magnetization degree of the magnetic shielding cabin;

[0008] Real-time monitoring the magnetization degree of the magnetic shielding cabin, and dynamically adjusting the parameters of current decay through a closed-loop feedback mechanism until the magnetization degree of the magnetic shielding cabin meets the target requirements.

[0009] The present invention provides a degaussing method for a magnetic shielding cabin. By adopting a phased degaussing strategy and precisely controlling the saturation and decay processes of the current, it not only quickly weakens the magnetization intensity on the surface and in the shallow layer but also ensures that the magnetic domain structure inside the material is uniformly demagnetized, thereby improving the uniformity and thoroughness of the overall degaussing effect. And through closed-loop feedback, the system can fine-tune the degaussing process according to real-time conditions, enabling the system to finely adjust the uniformity and intensity of the magnetic field and ensuring that the residual magnetism reaches the predetermined target. Through the synergistic effect of the phased degaussing strategy and the closed-loop feedback mechanism, efficient and precise degaussing of the multi-layer permalloy material inside the large magnetic shielding cabin is achieved.

[0010] In an alternative embodiment, applying a phased decaying oscillating current to the degaussing coil of the magnetic shielding cabin and gradually reducing the magnetization degree of the magnetic shielding cabin includes:

[0011] In the first stage, apply a decaying oscillating current with a first frequency to the degaussing coil of the magnetic shielding cabin until the magnetization degree of the magnetic shielding cabin reaches the first preset requirement;

[0012] In the second stage, apply a decaying oscillating current with a second frequency to the degaussing coil of the magnetic shielding cabin until the magnetization degree of the magnetic shielding cabin reaches the second preset requirement, where the second frequency is less than the first frequency;

[0013] In the third stage, apply a decaying oscillating current with a third frequency to the degaussing coil of the magnetic shielding cabin until the magnetization degree of the magnetic shielding cabin reaches the third preset requirement, where the third frequency is less than the second frequency.

[0014] In an alternative embodiment, monitoring the magnetization degree of the magnetic shielding cabin in real time and dynamically adjusting the parameters of the current decay through a closed-loop feedback mechanism until the magnetization degree of the magnetic shielding cabin reaches the target requirement includes:

[0015] Real-time collect the current of the degaussing coil, the terminal voltage, the magnetic field intensity at multiple points inside the magnetic shielding cabin, and the external disturbance magnetic field;

[0016] According to the magnetization state of the magnetic shielding cabin and the external disturbance magnetic field, predict the next magnetization trajectory and the residual magnetic field distribution;

[0017] Compare the root mean square error between the predicted value and the measured magnetic field distribution;

[0018] If the root mean square error exceeds the first threshold, then, with the goal of minimizing the residual magnetic field energy and the coil joule heat loss, roll-optimize the amplitude, frequency, and duty cycle of the degaussing current under the preset constraint conditions until the magnetization degree of the magnetic shielding cabin reaches the target requirement.

[0019] In an alternative embodiment, the method further includes:

[0020] If the current exceeds the second threshold, an overcurrent signal is generated, and a minimum conduction time adjustment circuit is activated according to the overcurrent signal, and the power supply is cut off after the minimum conduction time ends.

[0021] In an alternative embodiment, the method further includes:

[0022] Dynamically adjust the parameters of current decay according to the material of the magnetic shielding cabin and its magnetization state.

[0023] In a second aspect, the present invention provides a degaussing device for a magnetic shielding cabin, the device includes: a host computer, a high-precision programmable power supply system, a test system, an integrated control system, wherein,

[0024] The host computer is respectively connected to the high-precision programmable power supply system and the integrated control system, the high-precision programmable power supply system is also connected to the integrated control system, the host computer is used to monitor the optimized degaussing current parameters of the integrated control system, and the high-precision programmable power supply system is used to set the degaussing current parameters of the high-precision programmable power supply system according to the parameters in the host computer and the optimized degaussing current parameters of the integrated control system, and apply a saturation current and a phased decaying oscillating current to the degaussing coil of the magnetic shielding cabin;

[0025] The test system is connected to the integrated control system, the test system is used to monitor the magnetization degree of the magnetic shielding cabin, and send the magnetization degree to the integrated control system, and the integrated control system dynamically adjusts the parameters of current decay through a closed-loop feedback mechanism until the magnetization degree of the magnetic shielding cabin reaches the target requirement.

[0026] The present invention provides a degaussing device for a magnetic shielding cabin, which adopts a highly integrated design method, and integrates an AC power supply, a power management module, a power configuration module, a current decay circuit, a built-in programming control unit, a microprocessor, and a waveform function generator into a whole. This design improves the integration of the system and ensures the safety and stability of the degaussing process.

[0027] In an alternative embodiment, the high-precision programmable power supply system includes: an AC power supply, a power management module, a power configuration module, a current decay circuit, a built-in programming control unit, a microprocessor, and a waveform function generator, wherein,

[0028] The microprocessor is respectively connected to the power management module and the waveform function generator, the power configuration module is respectively connected to the power management module and the current decay circuit, the current decay circuit is also respectively connected to the waveform function generator and the built-in programming control unit, the built-in programming control unit is also connected to the AC power supply, and the AC power supply outputs an alternating current to the degaussing coil.

[0029] In an alternative embodiment, the high-precision programmable power supply system further includes: a system startup and protection circuit, which includes an inductor current overcurrent detection circuit, a trigger, and a minimum conduction time adjustment circuit. Among them,

[0030] The inductor current overcurrent detection circuit continuously monitors the current flowing through the degaussing coil. If the current exceeds the second threshold, it transmits an overcurrent signal to the trigger. After receiving the overcurrent signal, the trigger quickly activates the minimum conduction time adjustment circuit, and the minimum conduction time adjustment circuit cuts off the power supply after the minimum conduction time ends.

[0031] In a third aspect, the present invention provides a computer device, including: a memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor executes the computer instructions to perform the degaussing method of the magnetic shielding chamber in the first aspect or any corresponding embodiment thereof.

[0032] In a fourth aspect, the present invention provides a computer-readable storage medium, on which computer instructions are stored. The computer instructions are used to cause a computer to execute the degaussing method of the magnetic shielding chamber in the first aspect or any corresponding embodiment thereof. Description of the Drawings

[0033] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0034] Figure 1 is a schematic flowchart of the degaussing method of the magnetic shielding chamber according to an embodiment of the present invention;

[0035] Figure 2 is a schematic diagram of the magnetization process principle according to an embodiment of the present invention;

[0036] Figure 3 is a curve graph of the existing degaussing strategy function;

[0037] Figure 4 is a schematic diagram of the decaying oscillating current according to an embodiment of the present invention;

[0038] Figure 5 is a comparison graph of the magnetic field strength and the demagnetization curve required for demagnetizing different material objects according to an embodiment of the present invention;

[0039] Figure 6It is a current comparison diagram under different states according to an embodiment of the present invention;

[0040] Figure 7 It is a curve graph of a degaussing strategy function after real-time regulation improvement according to an embodiment of the present invention;

[0041] Figure 8 It is a structural block diagram of a degaussing device for a magnetic shielding cabin according to an embodiment of the present invention;

[0042] Figure 9 It is a structural block diagram of a high-precision programmable power supply system according to an embodiment of the present invention;

[0043] Figure 10 It is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. Detailed implementation manners

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0045] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0046] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can also be the internal connection of two elements. It can be a wireless connection or a wired connection. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0047] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0048] An embodiment of the present invention provides a degaussing method for a magnetic shielding cabin, which optimizes the degaussing control strategy to achieve the effect of precise demagnetization.

[0049] According to an embodiment of the present invention, an embodiment of a degaussing method for a magnetic shielding cabin is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0050] In this embodiment, a degaussing method for a magnetic shielding cabin is provided. Figure 1 It is a flowchart of the degaussing method for a magnetic shielding cabin according to an embodiment of the present invention, as Figure 1 shown, and this process includes the following steps:

[0051] Step S1, apply a saturation current to the degaussing coil of the magnetic shielding cabin to pre-magnetize the magnetic shielding cabin to the magnetic saturation state.

[0052] Specifically, for the efficient degaussing of the magnetic shielding cabin, the key lies in making the current in the degaussing coil in a saturated state. The saturation current is crucial for achieving a uniform magnetic field distribution and sufficient penetration, which is particularly obvious for the magnetic shielding cabin material with high magnetic permeability characteristics. Take the permalloy large magnetic shielding cabin as an example.

[0053] The magnetization process of permalloy follows the Jiles-Atherton (J-A) hysteresis model. According to the J-A model and the degaussing control strategy, before degaussing, first apply a saturation current with a saturated peak current to the degaussing coil of the magnetic shielding cabin to magnetize the permalloy material to make it reach the magnetic saturation state. The purpose of this operation is to make the magnetic domain structure inside the material reach a relatively uniform and completely aligned state, providing a uniform magnetic field distribution for the subsequent stage. The specific magnetization process is as Figure 2 shown in (a1), (a2) and (a3), and at this time, the magnetic domains are in the same direction as the external magnetic field.

[0054] Step S2, apply a phased decaying oscillating current to the degaussing coil of the magnetic shielding cabin to gradually reduce the magnetization degree of the magnetic shielding cabin.

[0055] Specifically, during the degaussing process, it is crucial to select an appropriate degaussing function strategy to achieve an ideal demagnetization effect. Commonly, mainly two degaussing current functions of linear decay oscillation and non-linear decay oscillation are adopted, as Figure 3 shown. Figure 3Figure (a) shows the linear decay oscillating demagnetization current function, which is characterized by the demagnetization current amplitude decreasing linearly with time, generating a steadily decreasing magnetic field. It is suitable for roughly reducing the magnetic field intensity, can uniformly reduce the magnetic flux density, and is commonly used for materials with relatively low coercivity. And Figure 3 Figure (b) shows the non-linear decay oscillating demagnetization current function, with rapid decay in the initial stage and slow decay subsequently, to balance the demagnetization efficiency and material response. This strategy provides more flexible adjustment of the decay rate, can be optimized according to the magnetization characteristics of the material, realizes more precise magnetic field control, and is suitable for avoiding sudden changes in magnetic flux density and reducing eddy current losses.

[0056] Figure 4 Shows an alternating current that gradually decays with time. This current is applied by a high-precision programmable power supply system, thereby generating a gradually weakening alternating magnetic field, which reduces the degree of order in the arrangement of magnetic domains inside the permalloy material. Figure 5 Further reveals the relationship between the magnetic field strength (H) and the magnetization intensity (M), that is, as the applied alternating magnetic field gradually weakens, the residual magnetization intensity in the material also decreases, indicating that the magnetization level of the material decreases correspondingly with the weakening of the external magnetic field.

[0057] In actual operation, a staged demagnetization strategy is adopted. Each stage is optimized according to the magnetic characteristics of the material, and the decay frequency, decay rate, and decay time of the decay oscillating current are gradually adjusted, thereby generating a gradually weakening alternating magnetic field and gradually reducing the residual magnetic field of the material to below dozens of nanoteslas.

[0058] In the embodiment of the present invention, through a carefully designed control strategy, the saturation and decay processes of the current are precisely regulated, effectively reducing the non-uniformity of magnetic domains inside the material, thereby achieving a uniform and effective demagnetization effect. The distorted sine wave current and normal sine wave current in the theoretical simulation are as Figure 6 shown. In addition, a multi-frequency alternating demagnetization current is adopted to break the magnetic domain arrangement at different frequency bands to improve the demagnetization effect. This method can further enhance the thoroughness of demagnetization and is applicable to application scenarios with extremely high precision requirements.

[0059] Step S3, monitor the magnetization degree of the magnetic shielding cabin in real time, and dynamically adjust the parameters of current decay through a closed-loop feedback mechanism until the magnetization degree of the magnetic shielding cabin meets the target requirements.

[0060] Specifically, the main objective of the closed-loop feedback mechanism is to correct the demagnetization parameters in real time and approach the limit demagnetization accuracy. At this stage, by arranging an array of magnetic sensor networks, a fluxgate magnetometer is used to monitor the magnetic field state in the cabin in real time, with an accuracy of ±0.1 nT and a sampling rate of 1000 Hz. The collected data is processed through low-pass filtering, and the magnetic field information is transmitted to the control system. The controller system dynamically adjusts the parameters of current decay, such as frequency, rate, and oscillation mode, according to the measurement results, ensuring that each adjustment can further optimize the effect of magnetic field cancellation. Through this closed-loop feedback, the system can fine-tune the demagnetization process according to real-time conditions, ensuring the accuracy of demagnetization.

[0061] In the embodiment of the present invention, the magnetic field distribution in the demagnetization area is monitored in real time, and the parameters of the demagnetization current function in the high-precision programmable AC power supply system are dynamically adjusted according to the monitoring results. This feedback-based control mechanism enables the system to finely adjust the uniformity and intensity of the magnetic field, thereby achieving a higher level of demagnetization effect. Through this method, the system can more precisely control the demagnetization process, ensuring the uniformity of the magnetic field and achieving a lower residual magnetic field level.

[0062] The present invention provides a demagnetization method for a magnetic shielding cabin. By adopting a phased demagnetization strategy, the saturation and decay processes of the current are precisely controlled, which not only rapidly weakens the magnetization intensity on the surface and in the shallow layer but also ensures that the magnetic domain structure inside the material is uniformly demagnetized, thereby improving the uniformity and thoroughness of the overall demagnetization effect. And through closed-loop feedback, the system can fine-tune the demagnetization process according to real-time conditions, enabling the system to finely adjust the uniformity and intensity of the magnetic field and ensuring that the residual magnetism reaches the predetermined target. Through the synergistic effect of the phased demagnetization strategy and the closed-loop feedback mechanism, efficient and precise demagnetization of multi-layer permalloy materials in a large magnetic shielding cabin is achieved.

[0063] In an alternative embodiment, step S2 includes:

[0064] Step S21, in the first stage, an attenuated oscillating current with a first frequency is applied to the demagnetization coil of the magnetic shielding cabin until the magnetization degree of the magnetic shielding cabin reaches the first preset requirement.

[0065] Step S22, in the second stage, an attenuated oscillating current with a second frequency is applied to the demagnetization coil of the magnetic shielding cabin until the magnetization degree of the magnetic shielding cabin reaches the second preset requirement, and the second frequency is less than the first frequency.

[0066] Step S23, in the third stage, an attenuated oscillating current with a third frequency is applied to the demagnetization coil of the magnetic shielding cabin until the magnetization degree of the magnetic shielding cabin reaches the third preset requirement, and the third frequency is less than the second frequency.

[0067] Specifically, after magnetization is completed, the first stage is entered. In the first stage, an alternating magnetic field strategy with a gradually decaying 50 Hz frequency, which is relatively high, is adopted. This can rapidly weaken the magnetization intensity on the surface and in the shallow layer of the permalloy material and quickly stimulate the irreversible movement of magnetic domain walls. At this time, magnetic hysteresis loss dominates energy dissipation, and a large-amplitude current is required to cover the entire material. However, due to the skin effect of the high-frequency alternating magnetic field, its penetration depth is limited, mainly acting on the surface and shallow layer areas of the material, having little effect on the magnetic domain structure inside the relatively thick material, and the demagnetization effect is limited. Therefore, it transitions to the second stage, the further attenuation stage. In this stage, the frequency transitions from high to low (10 - 50 Hz). The low-frequency magnetic field matches the relaxation time of magnetic domain flipping, disturbing the microscopic magnetic domains through a slowly decaying current, making the movement of magnetic domain walls relatively slow and reducing the residual of the reversible magnetization component. This stage can more uniformly reduce the magnetization intensity of the material and more effectively penetrate the interior of the material.

[0068] Therefore, before entering the first stage, this system first changes the magnetization state of the material by controlling the current in the demagnetizing coil, gradually guiding it from the ordered magnetic saturation to disorder, providing a uniform magnetic field distribution for the subsequent stage. The attenuation rate needs to be dynamically matched with the magnetic permeability of the material, and generally, the optimal attenuation coefficient is determined through pre-experiments or simulation optimization. Its non-linear attenuation function expression is:

[0069]

[0070] Among them, α is the attenuation rate coefficient (optimized through magnetic hysteresis loss), is the dynamic phase modulation to enhance the randomness of magnetic domain flipping, is the attenuation frequency. Figure 7 It mainly shows the process of entering each stage according to the set time and achieving demagnetization by gradually reducing the frequency, while other parameters are fine-tuned to optimize the overall performance. If the residual magnetic field is relatively high, generally, the attenuation coefficient α is reduced by 10% - 30% and the demagnetization time is extended. The specific parameter settings are usually first determined through pre-experiments or simulations and then further optimized by the control algorithm of the system to ensure that the magnetic field can still be effectively eliminated while the current weakens.

[0071] The third stage is the deep attenuation stage: After the attenuation in the second stage ends, the system enters the deep attenuation stage. In this stage, the demagnetization process becomes more refined because the magnetic moments in grain boundaries, defects, or stress concentration regions are difficult to eliminate through conventional demagnetization due to the pinning effect. By using more complex attenuation functions and oscillation modes, the system further reduces the magnetic field intensity, addresses deeper magnetic domain disorder problems, and eliminates nanoscale residual magnetic moments and the grain boundary pinning effect. This stage is crucial because it determines whether the final magnetic field can reach the expected extremely low level. Usually, a demagnetization frequency of 1 - 10 Hz is adopted, the relative amplitude gradually approaches 0, and its attenuation period is more intensive, which can effectively reduce the residual stress caused by the magneto-elastic effect, making the residual remanence approach the remanence of the material body. Among them, the first frequency is in the high-frequency band, taking 50 Hz as an example. The second frequency is in the low-frequency band, between 10 - 50 Hz. The third frequency is between 1 - 10 Hz. The first preset requirement is to weaken the magnetization intensity on the surface and in the shallow layer of the permalloy material. The second preset requirement is to uniformly reduce the magnetization intensity of the material. The third preset requirement is to eliminate nanoscale residual magnetic moments and the grain boundary pinning effect.

[0072] The embodiment of the present invention uses a high-performance microcontroller in cooperation with an advanced current control algorithm to achieve precise control of the output current to adapt to the magnetization characteristics of permalloy. In particular, the demagnetization system can easily provide a saturation current for the demagnetization coil with high impedance and high inductance characteristics, ensuring that the coil can operate at full power, thereby achieving demagnetization with high efficiency. Since large magnetic shielding cabins are usually made of permalloy materials, the design of the embodiment of the present invention fully considers its characteristics of high magnetic permeability and low coercivity, as well as the specific requirements for the power supply system during the demagnetization process. In addition, considering that large shielding cabins require multi-winding demagnetization coils, the embodiment of the present invention particularly optimizes the support ability for large-impedance and high-inductance loads by expanding the output power of the high-precision power supply system and improving its voltage regulation ability. The demagnetization coils are wound in series in multiple layers and on multiple sides inside the large magnetic shielding cabin to achieve uniform demagnetization synchronously and avoid the problem of incomplete local demagnetization. Additionally, to reduce the inductance and overall impedance of the coil, a parallel arrangement of the demagnetization coils can be adopted to reduce the power demand on the power supply.

[0073] In an alternative embodiment, step S3 includes:

[0074] Step S31, real-time collect the current of the demagnetization coil, the terminal voltage, the magnetic field intensity at multiple points inside the magnetic shielding cabin, and the external disturbing magnetic field;

[0075] Step S32, predict the next magnetization trajectory and the residual magnetic field distribution according to the magnetization state of the magnetic shielding cabin and the external disturbing magnetic field;

[0076] Step S33, compare the root mean square error between the predicted value and the measured magnetic field distribution;

[0077] In step S34, if the root mean square error exceeds the first threshold, the amplitude, frequency, and duty cycle of the demagnetization current are optimized iteratively under preset constraint conditions with the goal of minimizing the residual magnetic field energy and the Joule heat loss of the coil until the magnetization level of the magnetic shielding cabin meets the target requirements.

[0078] Specifically, when the demagnetization system starts, the integrated control unit loads preset programs and parameters input by the user, such as the demagnetization target (e.g., residual magnetic field threshold), material type, safety margin (maximum current / voltage of the demagnetization coil), etc. The coil current, terminal voltage, and magnetic field strength at multiple points inside the shielding cabin are collected in real time through high-bandwidth current sensors, differential voltage probes, and a distributed fluxgate magnetometer array. The control unit calls a hysteresis calculation engine based on the dynamic J-A model, which pre-stores the magnetic characteristic parameters (saturation magnetization Ms, magnetic domain coupling coefficient α, etc.) of different materials and corrects the eddy current loss coefficient and temperature drift in real time through the online recursive least squares method. The model predicts the next magnetization trajectory and residual magnetic field distribution based on the current magnetization state (H, M) and the external perturbation magnetic field (provided by the magnetic field sensor). Here, the magnetization state is characterized by the magnetic field strength H and the magnetization intensity M. The magnetic field strength H is an auxiliary physical quantity mainly used to describe the contribution of the external magnetic field source. It focuses on the relationship between the magnetic field and the current generating the magnetic field, and its definition formula is: H = B / μ - M. Here, B is the magnetic induction intensity, μ is the magnetic permeability, and M is the magnetization intensity. The magnetization intensity M represents the vector sum of all molecular magnetic moments per unit volume and is used to describe the magnetization level of the magnetic material under the action of the external magnetic field. The relationship between the magnetization intensity M and the magnetic field strength H can be described by the magnetic susceptibility χ: M = χH. Further, the magnetic induction intensity B is obtained through sensor testing, and the magnetic permeability μ and the magnetic susceptibility χ are obtained through material instrument testing.

[0079] Subsequently, the system compares the root mean square error (RMSE) between the predicted value and the measured magnetic field distribution. If it exceeds the first threshold, the model predictive controller (MPC) is triggered. The MPC optimizes the amplitude, frequency, and duty cycle of the demagnetization current iteratively with the goal of minimizing the residual magnetic field energy and the Joule heat loss of the coil under constraint conditions (maximum current / voltage, temperature rise rate) and generates a PWM signal. At the same time, the secondary control loop monitors the coil current and the ambient magnetic field. If overcurrent or local overheating of the demagnetization coil is detected, it immediately switches to the safe mode and gradually reduces the load. Here, the first threshold depends on the specific situation.

[0080] When the external magnetic field is completely eliminated, the magnetic domains inside the material are randomly arranged, marking the completion of the demagnetization process. The core of the entire demagnetization process lies in using an alternating magnetic field with decaying oscillations to gradually reduce the order of the magnetic domains inside the material, achieving effective demagnetization of different material objects and ensuring the high efficiency and consistency of the demagnetization effect. This process highlights the influence of the external magnetic field on the arrangement of magnetic domains and the important role of the change in magnetic domain arrangement on the magnetization state of the magnetic core.

[0081] In an alternative embodiment, the method further includes:

[0082] Step S4, if the current exceeds the second threshold, an overcurrent signal is generated, and the minimum conduction time adjustment circuit is activated according to the overcurrent signal, and the power supply is cut off after the minimum conduction time ends.

[0083] Specifically, in the demagnetization system of the magnetic shielding cabin, the inductor current overcurrent detection circuit in the power supply module is responsible for continuously monitoring the current flowing through the demagnetizing coil. Once the detected current level exceeds the second threshold (a preset safety threshold), a digital isolator (such as an optocoupler or a magnetic coupler) is used to transmit the overcurrent signal to the trigger, and the trigger delay < 1 μs. After receiving the overcurrent signal, the trigger will quickly activate the minimum conduction time adjustment circuit to ensure that the system has been operating stably for a preset minimum time before cutting off the power supply, so as to cut off the power supply after the minimum conduction time ends. This process not only protects the demagnetizing coil from overcurrent damage but also effectively isolates the influence of power supply noise and DC bias, ensuring the safety of the demagnetization process and the overall stability of the system.

[0084] In an alternative embodiment, the method further includes:

[0085] Step S5, dynamically adjust the parameters of current decay according to the material of the magnetic shielding cabin and its magnetization state.

[0086] Specifically, for the differences in the magnetization states of different ferromagnetic materials, it is necessary to dynamically optimize the demagnetization control strategy based on the magnetization curve, hysteresis loop, and effective magnetic permeability characteristics measured by the dynamic method (such as alternating magnetic field excitation). Specifically, by quantifying the coercive force ( Hc ), remanence ( Br ), and hysteresis loss and other key parameters of the material, the amplitude, frequency, and decay function of the demagnetization current can be adaptively adjusted to match the dynamic magnetic domain response characteristics of the material, thereby significantly reducing the residual magnetic field and improving the static shielding factor (SF) of the magnetic shielding cabin. Figure 5 In which Object 1 and Object 2 represent that there are differences in the required magnetic field strength and demagnetization curve when demagnetizing different material objects.

[0087] The present invention provides a demagnetization device for a magnetic shielding cabin, such as Figure 8As shown in the figure, it includes: a host computer, a high-precision programmable power supply system, a test system, and an integrated control system.

[0088] Among them, the host computer is respectively connected to the high-precision programmable power supply system and the integrated control system, and the high-precision programmable power supply system is also connected to the integrated control system. The host computer is used to monitor the degaussing current parameters optimized by the integrated control system. The high-precision programmable power supply system is used to set the degaussing current parameters of the high-precision programmable power supply system according to the parameters in the host computer and the degaussing current parameters optimized by the integrated control system, and apply a saturation current and a phased decaying oscillation current to the degaussing coil of the magnetic shielding chamber. The test system is connected to the integrated control system. The test system is used to monitor the magnetization degree of the magnetic shielding chamber and send the magnetization degree to the integrated control system. The integrated control system dynamically adjusts the parameters of the current decay through a closed-loop feedback mechanism until the magnetization degree of the magnetic shielding chamber meets the target requirements.

[0089] Specifically, the overall design is shown in Figure 8 As shown in the figure, it mainly includes a high-precision programmable power supply system, a degaussing coil (the degaussing control function acts on the degaussing coil, and the power supply generates the corresponding degaussing current according to the function), a test system, and an integrated control system, thus integrating a closed-loop feedback degaussing system. Among them, the high-precision programmable power supply system is the power part of the overall integrated system. It sets the degaussing current parameters of the high-precision programmable power supply system according to the parameters in the host computer and the degaussing current parameters optimized by the integrated control system, and applies a saturation current and a phased decaying oscillation current to the degaussing coil of the magnetic shielding chamber. The high-precision programmable power supply system includes a programmable power controller that can edit online and precisely control the output of current, voltage, time, and frequency at different stages. The power supply system is designed to provide stable current and voltage to drive the degaussing coil. The degaussing control strategy is the trigger instruction of the power supply system, which is responsible for adjusting the current and magnetic field according to the preset degaussing function strategy. It includes a user interface that allows the operator to input parameters or select different degaussing modes (linear decaying oscillation function, non-linear decaying oscillation function, logarithmic decaying oscillation function, exponential decaying oscillation function). The test system includes an array-type test unit, whose main function is to monitor and measure the magnetic field strength during and after the degaussing process, and provide detailed data on the magnetic field distribution inside the chamber after degaussing. The integrated control system is used to receive the feedback signal from the test system, and according to the feedback signal, dynamically adjust the current output parameters (such as current magnitude, frequency, and decay mode) of the drive circuit, and then transmit them to the high-precision programmable power supply system to re-run the degaussing program for demagnetization to ensure that the residual magnetic field of the material reaches the predetermined target. The host computer refers to integrating the computer operating system into the degaussing device. The computer operating system is used to run the control software, which can execute complex algorithms to optimize the degaussing process.

[0090] In an alternative embodiment, a high-precision programmable power supply system, such as Figure 9 shown, includes: an AC power supply, a power management module, a power configuration module, a current attenuation circuit, a built-in programming control unit, a microprocessor, and a waveform function generator. Among them, the microprocessor is respectively connected to the power management module and the waveform function generator, the power configuration module is respectively connected to the power management module and the current attenuation circuit, the current attenuation circuit is also respectively connected to the waveform function generator and the built-in programming control unit, the built-in programming control unit is also connected to the AC power supply, and the AC power supply outputs an alternating current to the degaussing coil.

[0091] Specifically, the high-precision programmable power supply system of the present invention, such as Figure 9 shown, is an integrated power supply system designed specifically for large magnetic shielding cabins, aiming to achieve efficient degaussing of permalloy materials. Among them, the AC power supply serves as the input power supply of the system, providing alternating current energy and providing basic power input for the entire system. It is usually connected to the alternating current output by the mains or a generator. The filter filters out high-frequency noise, harmonics, and electromagnetic interference (EMI) in the power supply, improves the power quality, protects the subsequent circuits from interference, and ensures the stability of the signal and the power supply. The degaussing coil acts on the magnetic shielding cabin to achieve demagnetization and is equivalent to the load of the power supply here. The power management module monitors the voltage, current, and temperature of the power supply and distributes electrical energy to different subsystems. It mainly realizes overvoltage, overcurrent, and short-circuit protection, optimizes energy distribution, and ensures the safe operation of the system.

[0092] The power configuration module includes a matrix parallel power configuration, a bidirectional DC / DC converter, pulse width modulation, and a frequency conversion unit. Among them, the matrix parallel power configuration forms a redundant structure by paralleling multiple power modules, improving the system's power output capacity and enhancing reliability (a single module failure does not affect the overall operation). The bidirectional DC / DC converter is used to generate a variable alternating magnetic field to adapt to the dynamic requirements during the degaussing process, realizing bidirectional conversion (boosting / buckling) of the DC voltage and energy feedback, adapting to different voltage requirements, supporting energy recovery, and improving energy efficiency. Pulse width modulation controls the output power or realizes signal modulation by adjusting the duty cycle of the pulse signal. The frequency conversion unit adjusts the power supply output frequency to adapt to the frequency requirements of different loads (such as variable frequency drive devices) and optimizes the system compatibility. The bidirectional DC / DC converter works in coordination with the power management module to dynamically adjust the power supply output, ensuring uniform distribution of the magnetic field and effective penetration of the object to be degaussed. The matrix parallel structure is adopted to support multi-level voltage output to meet the high-power degaussing requirements.

[0093] The current decay circuit limits the rapid change of current, slows down the current decay rate, prevents the impact on devices caused by current mutation, and protects sensitive components (such as capacitors and inductors). The microprocessor, as the core controller, runs algorithms and coordinates the work of each module, adjusts parameters (such as voltage and frequency), and realizes intelligent control. The waveform function generator is used to generate specific waveforms, such as sine waves, square waves, pulse waves, etc. The switch circuit controls the current path by turning on and off the circuit through semiconductor devices, and realizes power distribution or load switching. The timing control circuit ensures that each module operates according to the preset time sequence, coordinates the power supply startup, operation, alternating current amplitude and frequency transformation, and mode switching, and avoids timing conflicts. The built-in programming control unit provides a user-programmable interface, supports custom control logic, and meets the diverse application requirements. Through the collaborative work of these modules above, the high-precision degaussing power supply system can realize efficient, stable, and intelligent power management and magnetic field elimination functions, and is applicable to various application scenarios with high-precision and high-reliability requirements.

[0094] The system realizes PWM control through the microprocessor to optimize energy efficiency, and uses DSP to process complex control algorithms to achieve precise degaussing effects. The timing control unit and the built-in programming control unit are respectively responsible for precisely controlling the degaussing time, and allowing users to adjust current, voltage, and frequency parameters according to needs, ensuring the accuracy and high automation of the degaussing process. The entire system is designed compactly and efficiently, and is specially designed to meet the precise degaussing requirements of permalloy materials in large magnetic shielding cabins.

[0095] The present invention provides a degaussing device for a magnetic shielding cabin, which adopts a highly integrated design method, and integrates an AC power supply, a power management module, a power configuration module, a current decay circuit, a built-in programming control unit, a microprocessor, and a waveform function generator into a whole. This design improves the integration degree of the system, and at the same time ensures the safety and stability of the degaussing process.

[0096] In an optional implementation manner, the high-precision programmable power supply system further includes: a system startup and protection circuit, and the system startup and protection circuit includes an inductor current overcurrent detection circuit, a trigger, and a minimum conduction time adjustment circuit. Among them, the inductor current overcurrent detection circuit continuously monitors the current flowing through the degaussing coil. If the current exceeds the second threshold, it transmits an overcurrent signal to the trigger. After receiving the overcurrent signal, the trigger quickly activates the minimum conduction time adjustment circuit, and the minimum conduction time adjustment circuit cuts off the power supply after the minimum conduction time ends.

[0097] Specifically, the system startup and protection circuit manages the startup sequence of the system, implements multiple protection mechanisms to ensure the safety of the startup process and prevent inrush current, and integrates overvoltage, overcurrent, and overheat protection functions. To ensure the security of the system, an overload and short-circuit protection mechanism is integrated into the microprocessor of the high-precision programmable power supply system to prevent equipment damage and operational risks. In the design of the power module, special attention is paid to the bias problem and power isolation. By integrating an inductor current overcurrent detection circuit, a trigger, and a minimum conduction time adjustment circuit, the power supply can be quickly cut off when the inductor current is overcurrent, effectively isolating the influence of the power supply and DC bias.

[0098] An embodiment of the present invention also provides a computer device. Figure 10 FIG. is a schematic structural diagram of a computer device provided by an optional embodiment of the present invention. As Figure 10 shown, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Each component communicates with each other using different buses and can be installed on a common motherboard or in other ways as needed. The processor can process instructions executed within the computer device, including instructions stored in the memory or on the memory to display graphical information of the GUI on an external input / output device (such as a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (such as a server array, a set of blade servers, or a multi-processor system). Figure 10 Here, one processor 10 is taken as an example.

[0099] The processor 10 can be a central processor, a network processor, or a combination thereof. Among them, the processor 10 can further include a hardware chip. The above hardware chip can be an application-specific integrated circuit, a programmable logic device, or a combination thereof. The above programmable logic device can be a complex programmable logic device, a field programmable gate array, a generic array logic, or any combination thereof.

[0100] Among them, the memory 20 stores instructions executable by at least one processor 10, so that the at least one processor 10 executes the method shown in the above embodiment.

[0101] The memory 20 may include a program storage area and a data storage area. Among them, the program storage area can store an operating system and application programs required for at least one function; the data storage area can store data created according to the use of the computer device, etc. In addition, the memory 20 may include high-speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid-state storage devices. In some alternative embodiments, the memory 20 may optionally include a memory remotely provided with respect to the processor 10, and these remote memories may be connected to the computer device through a network. Examples of the above-mentioned network include but are not limited to the Internet, intranet, local area network, mobile communication network, and combinations thereof.

[0102] The memory 20 may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk, or solid-state drive; the memory 20 may further include a combination of the above types of memory.

[0103] The computer device further includes an input device 30 and an output device 40. The processor 10, the memory 20, the input device 30, and the output device 40 may be connected through a bus or other means. Figure 10 Taking connection through a bus as an example.

[0104] The input device 30 can receive input digital or character information, and generate key signal inputs related to the user settings and function control of the computer device, such as a touch screen, keypad, mouse, trackpad, touchpad, pointing stick, one or more mouse buttons, trackball, joystick, etc. The output device 40 may include a display device, an auxiliary lighting device (such as an LED), and a tactile feedback device (such as a vibration motor), etc. The above-mentioned display device includes but is not limited to a liquid crystal display, light-emitting diode, display, and plasma display. In some alternative embodiments, the display device may be a touch screen.

[0105] Embodiments of the present invention also provide a computer-readable storage medium. The methods according to the embodiments of the present invention can be implemented in hardware, firmware, or be implemented as computer code that can be recorded on a storage medium, or be implemented as computer code that is originally stored in a remote storage medium or a non-transitory machine-readable storage medium and downloaded through a network and will be stored in a local storage medium, so that the methods described herein can be stored as such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only memory, a random access memory, a flash memory, a hard disk, or a solid-state drive, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code, and when the software or computer code is accessed and executed by the computer, the processor, or the hardware, the methods shown in the above embodiments are implemented.

[0106] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A degaussing method for a magnetic shielding cabin, characterized in that, The method includes: Applying a saturation current to the degaussing coil of the magnetic shielding chamber to pre-magnetize the magnetic shielding chamber to the magnetic saturation state; Applying a phased decaying oscillating current to the degaussing coil of the magnetic shielding chamber to gradually reduce the magnetization degree of the magnetic shielding chamber; Real-time monitoring the magnetization degree of the magnetic shielding chamber, and dynamically adjusting the parameters of current decay through a closed-loop feedback mechanism until the magnetization degree of the magnetic shielding chamber meets the target requirements; The applying a phased decaying oscillating current to the degaussing coil of the magnetic shielding chamber to gradually reduce the magnetization degree of the magnetic shielding chamber includes: In the first stage, applying a decaying oscillating current with a first frequency to the degaussing coil of the magnetic shielding chamber until the magnetization degree of the magnetic shielding chamber meets the first preset requirement; In the second stage, applying a decaying oscillating current with a second frequency to the degaussing coil of the magnetic shielding chamber until the magnetization degree of the magnetic shielding chamber meets the second preset requirement, where the second frequency is less than the first frequency; In the third stage, applying a decaying oscillating current with a third frequency to the degaussing coil of the magnetic shielding chamber until the magnetization degree of the magnetic shielding chamber meets the third preset requirement, where the third frequency is less than the second frequency; The real-time monitoring the magnetization degree of the magnetic shielding chamber, and dynamically adjusting the parameters of current decay through a closed-loop feedback mechanism until the magnetization degree of the magnetic shielding chamber meets the target requirements includes: Real-time collecting the current, terminal voltage of the degaussing coil, magnetic field intensities at multiple points inside the magnetic shielding chamber, and external disturbance magnetic fields; Predicting the next magnetization trajectory and residual magnetic field distribution based on the magnetization state of the magnetic shielding chamber and the external disturbance magnetic field; Comparing the root mean square error between the predicted value and the measured magnetic field distribution; If the root mean square error exceeds the first threshold, then taking minimizing the residual magnetic field energy and coil joule heat loss as the optimization objective, and rolling-optimizing the amplitude, frequency, and duty cycle of the degaussing current under preset constraint conditions until the magnetization degree of the magnetic shielding chamber meets the target requirements.

2. The degaussing method of the magnetic shielding cabin according to claim 1, wherein, The method further includes: If the current exceeds the second threshold, generating an overcurrent signal, activating a minimum conduction time adjustment circuit according to the overcurrent signal, and cutting off the power supply after the minimum conduction time ends.

3. The degaussing method of the magnetic shielding cabin according to claim 1, wherein, The method further includes: Dynamically adjusting the parameters of current decay according to the material of the magnetic shielding chamber and its magnetization state.

4. A degaussing device for a magnetic shielding chamber, characterized in that, The device includes: a host computer, a high-precision programmable power supply system, a test system, and an integrated control system, where The host computer is respectively connected to the high-precision programmable power supply system and the integrated control system, the high-precision programmable power supply system is also connected to the integrated control system, the host computer is used to monitor the optimized degaussing current parameters of the integrated control system, and the high-precision programmable power supply system is used to set the degaussing current parameters of the high-precision programmable power supply system according to the parameters in the host computer and the optimized degaussing current parameters of the integrated control system, and apply a saturation current and a phased decaying oscillating current to the degaussing coil of the magnetic shielding chamber; The test system is connected to the integrated control system. The test system is used to monitor the magnetization degree of the magnetic shielding chamber and send the magnetization degree to the integrated control system. The integrated control system dynamically adjusts the parameters of current decay through a closed-loop feedback mechanism until the magnetization degree of the magnetic shielding chamber meets the target requirements; Applying a phased decaying oscillating current to the demagnetizing coil of the magnetic shielding chamber to gradually reduce the magnetization degree of the magnetic shielding chamber, including: In the first stage, applying a decaying oscillating current with a first frequency to the demagnetizing coil of the magnetic shielding chamber until the magnetization degree of the magnetic shielding chamber meets the first preset requirement; In the second stage, applying a decaying oscillating current with a second frequency to the demagnetizing coil of the magnetic shielding chamber until the magnetization degree of the magnetic shielding chamber meets the second preset requirement, where the second frequency is less than the first frequency; In the third stage, applying a decaying oscillating current with a third frequency to the demagnetizing coil of the magnetic shielding chamber until the magnetization degree of the magnetic shielding chamber meets the third preset requirement, where the third frequency is less than the second frequency; Monitoring the magnetization degree of the magnetic shielding chamber and dynamically adjusting the parameters of current decay through a closed-loop feedback mechanism until the magnetization degree of the magnetic shielding chamber meets the target requirements, including: Real-time collecting the current of the demagnetizing coil, the terminal voltage, the magnetic field intensity at multiple points inside the magnetic shielding chamber, and the external disturbance magnetic field; Predicting the next magnetization trajectory and the residual magnetic field distribution according to the magnetization state of the magnetic shielding chamber and the external disturbance magnetic field; Comparing the root mean square error between the predicted value and the measured magnetic field distribution; If the root mean square error exceeds the first threshold, then taking minimizing the residual magnetic field energy and the coil joule heat loss as the optimization objective, and rolling-optimizing the amplitude, frequency, and duty cycle of the demagnetizing current under the preset constraint conditions until the magnetization degree of the magnetic shielding chamber meets the target requirements.

5. The degaussing device of the magnetic shielding cabin according to claim 4, characterized in that, The high-precision programmable power supply system includes: an AC power supply, a power management module, a power configuration module, a current decay circuit, a built-in programming control unit, a microprocessor, and a waveform function generator, where, The microprocessor is respectively connected to the power management module and the waveform function generator. The power configuration module is respectively connected to the power management module and the current decay circuit. The current decay circuit is also respectively connected to the waveform function generator and the built-in programming control unit. The built-in programming control unit is also connected to the AC power supply. The AC power supply outputs an alternating current to the demagnetizing coil.

6. The degaussing device of the magnetic shielding cabin according to claim 5, characterized in that, The high-precision programmable power supply system further includes: a system startup and protection circuit. The system startup and protection circuit includes an inductor current overcurrent detection circuit, a trigger, and a minimum conduction time adjustment circuit, where, The inductor current overcurrent detection circuit continuously monitors the current flowing through the demagnetizing coil. If the current exceeds the second threshold, it transmits an overcurrent signal to the trigger. After receiving the overcurrent signal, the trigger quickly activates the minimum conduction time adjustment circuit, and the minimum conduction time adjustment circuit cuts off the power supply after the minimum conduction time ends.

7. A computer device, characterized in that, Including: A memory and a processor, which are communicatively connected to each other. Computer instructions are stored in the memory, and the processor executes the computer instructions to perform the degaussing method of the magnetic shielding chamber according to any one of claims 1 to 3.

8. A computer-readable storage medium, characterized in that, Computer instructions are stored on the computer-readable storage medium, and the computer instructions are used to cause a computer to execute the degaussing method of the magnetic shielding chamber according to any one of claims 1 to 3.

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