Alternating-current electromagnetic field stress measurement system and method

Abstract

An alternating-current electromagnetic field stress measurement system, comprising: an excitation signal generation module, an alternating-current electromagnetic field stress measurement stress probe, a signal amplification circuit, an A / D conversion circuit and a processor, wherein the excitation signal generation module is used for loading a sinusoidal alternating-current signal to an excitation coil of the alternating-current electromagnetic field stress measurement stress probe, such that a periodically changing electric field is generated on a measured magnetic object; the alternating-current electromagnetic field stress measurement stress probe is used for sequentially routing a stress characterization signal, which is detected from the measured magnetic object, through the signal amplification circuit and the A / D conversion circuit, and then sending the stress characterization signal to the processor; and the processor is used for processing the received stress characterization signal by using an optimized J-A model in which an implicit equation originally characterizing a change in the magnetization intensity or magnetic induction intensity along with stress is made explicit, so as to calculate the stress of the measured magnetic object. The alternating-current electromagnetic field stress measurement system can monitor the stress increase trend in real time, and notice potential dangers in time. Further comprised is an alternating-current electromagnetic field stress measurement method and a computer program for executing the alternating-current electromagnetic field stress measurement method.

Description

AC electromagnetic field stress detection system and method

[0001] This disclosure claims priority to Chinese patent application No. 202410934811.2, filed on July 12, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to the field of stress detection technology, and in particular to an AC electromagnetic field stress detection system and method. Background Technology

[0003] Oil and gas pipelines may be affected by geological subsidence, surface displacement, and geological disasters during operation, causing changes in pipeline stress. Stress detection can monitor the stress growth trend in pipelines in real time, promptly identify potential dangers, and thus take measures to reduce or eliminate additional stress, ensuring the long-term safe operation of oil and gas pipelines. Summary of the Invention

[0004] In a first aspect, embodiments of this disclosure provide an AC electromagnetic field stress detection system. This AC electromagnetic field stress detection system includes: an excitation signal generation module, an AC electromagnetic field stress measurement (ACSM) probe, a signal amplification circuit, an analog-to-digital (A / D) conversion circuit, and a processor. The excitation signal generation module is used to: load a sinusoidal AC signal onto the excitation coil of the ACSM probe to generate a periodically changing electric field on the tested magnetic object. The ACSM probe is used to: send the stress characterization signal detected on the tested magnetic object to the processor after passing it sequentially through the signal amplification circuit and the A / D conversion circuit. The processor is used to: process the received stress characterization signal using an optimized JA model that makes the implicit equations characterizing the change of magnetization or magnetic induction intensity with stress explicit, and calculate the stress of the tested magnetic object.

[0005] In some embodiments, the process of obtaining the optimized JA model includes:

[0006] An optimized JA model is obtained by using a polynomial fitting method.

[0007] In some embodiments, the optimized JA model is: M = ax 7 +bx 6 +cx 5 +dx 4 +ex 3 +fx 2 +gx+h, M represents magnetization, x represents stress, a=-1.313×10 -51 b = 1.036 × 10 -42 c = -3.26 × 10 -34d = 5.138 × 10 -26 e = -4.092 × 10 -18 f = 1.346 × 10 -10 g = -1.342 × 10 -4 h = -49.31.

[0008] In some embodiments, the AC electromagnetic field stress detection system further includes a power amplification module, and the excitation signal generation module is a direct digital frequency synthesizer (DDS) chip. The sinusoidal AC signal generated by the DDS chip is amplified by the power amplification module and then applied to the excitation coil of the ACSM stress probe.

[0009] In some embodiments, the A / D conversion circuit includes multiple conversion channels, the resolution of the A / D conversion circuit is not less than 1 bit, and the A / D conversion circuit has a high-speed digital-to-analog transmission interface.

[0010] Secondly, this disclosure also provides an AC electromagnetic field stress detection method. The AC electromagnetic field stress detection method includes: an excitation signal generation module loading a sinusoidal AC signal onto the excitation coil of an ACSM stress probe to generate a periodically changing electric field on the magnetic object under test; the ACSM stress probe transmitting the stress characterization signal detected on the magnetic object under test sequentially through a signal amplification circuit and an analog-to-digital (A / D) conversion circuit to a processor; and the processor processing the received stress characterization signal using an optimized JA model that explicitly expresses the implicit equations characterizing the change of magnetization or magnetic induction intensity with stress, and calculating the stress of the magnetic object under test.

[0011] In some embodiments, the process of obtaining the optimized JA model includes:

[0012] An optimized JA model is obtained by using a polynomial fitting method.

[0013] In some embodiments, the optimized JA model is: M = ax 7 +bx 6 +cx 5 +dx 4 +ex 3 +fx 2 +gx+h, M represents magnetization, x represents stress, a=-1.313×10 -51 b = 1.036 × 10 -42 c = -3.26 × 10 -34 d = 5.138 × 10 -26 e = -4.092 × 10 -18 f = 1.346 × 10 -10 g = -1.342 × 10 -4h = -49.31.

[0014] In some embodiments, the excitation signal generation module is a DDS chip, and the sinusoidal AC signal generated by the DDS chip is amplified by a power amplifier module and then applied to the excitation coil of the ACSM stress probe.

[0015] In some embodiments, the A / D conversion circuit includes multiple conversion channels, the resolution of the A / D conversion circuit is not less than 1 bit, and the A / D conversion circuit has a high-speed digital-to-analog transmission interface.

[0016] Thirdly, embodiments of this disclosure provide a computer-readable storage medium including computer instructions that, when executed on an electronic device, cause the electronic device to perform the method according to the second aspect and its embodiments.

[0017] Fourthly, embodiments of this disclosure provide a computer program product that, when run on a computer, causes the computer to perform the methods of the second aspect and its embodiments.

[0018] Fifthly, embodiments of this disclosure provide a computer program that, when run on a computer, causes the computer to perform the methods of the second aspect and its embodiments. Attached Figure Description

[0019] Other features, objects, and advantages of this disclosure will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0020] Figure 1 is a schematic diagram of an AC electromagnetic field stress detection system according to some embodiments.

[0021] Figure 2 is a schematic diagram of another AC electromagnetic field stress detection system according to some embodiments.

[0022] Figure 3 is a structural schematic diagram of another AC electromagnetic field stress detection system according to some embodiments.

[0023] Figure 4 is a flowchart illustrating an AC electromagnetic field stress detection method according to some embodiments. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0025] The technical solutions of the embodiments of this disclosure will now be described with reference to the accompanying drawings. In the description of this disclosure, unless otherwise stated, " / " indicates that the objects before and after are in an "or" relationship; for example, A / B can represent A or B. "And / or" in this disclosure is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: only A, A and B, only B, where A and B can be singular or plural. Furthermore, in the description of this disclosure, unless otherwise stated, "multiple" refers to two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items.

[0026] Furthermore, to facilitate a clear description of the technical solutions of the embodiments of this disclosure, the terms "first" and "second" are used in the embodiments of this disclosure to distinguish identical or similar items with substantially the same function and effect. Those skilled in the art will understand that the expressions "first" and "second" do not limit the quantity or execution order, and the expressions "first" and "second" are not necessarily different.

[0027] It should be noted that the terms "first," "second," etc., used in the specification and claims of this disclosure are used to distinguish similar objects and represent a specific order or sequence. Where appropriate, the order of use for similar objects can be interchanged so that the embodiments of this disclosure described herein can be implemented in an order other than that shown or described.

[0028] In this disclosure, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this disclosure should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present related concepts in some way to facilitate understanding. Unless otherwise specified, the functions, steps, etc., shown in this disclosure may occur in a different order than those shown in this disclosure, and other functions, steps, etc., may exist between two adjacent functions, steps, etc., shown in this disclosure.

[0029] In 2017, Baker Hughes developed the world's first online axial stress measurement probe specifically designed for pipeline inspection instruments. The probe is based on the principle of alternating electromagnetics and has been applied to a natural gas pipeline. However, the actual measurement results are only qualitative and cannot be quantitative.

[0030] In recent years, extensive research has been conducted on the online rapid measurement of axial stress in oil and gas pipelines, mainly using remanent magnetization and metal memory methods. However, there are currently no products available for online rapid measurement of axial stress in actual pipelines. The key challenge lies in the extremely weak stress characterization signal, which is affected by temporal and spatial variations, velocity, material, and lift-off. Some methods exhibit excellent expression in laboratory environments, but when used for engineering environment testing, the signal-to-noise ratio is too poor to be interpretable.

[0031] To address the aforementioned technical problems, this disclosure provides an AC electromagnetic field stress detection system.

[0032] As shown in Figure 1, an AC electromagnetic field stress detection system according to an embodiment of the present disclosure includes: an excitation signal generation module, an ACSM (Alternating Current Stress Measurement) stress probe, a signal amplification circuit, an A / D conversion circuit, and a processor;

[0033] The excitation signal generation module is used to: load a sinusoidal AC signal onto the excitation coil of the ACSM stress probe to generate a periodically changing electric field on the magnetic object under test;

[0034] The ACSM stress probe is used to: transmit the stress characterization signal detected by the magnetic object under test to the processor after passing it through a signal amplification circuit and an A / D conversion circuit in sequence;

[0035] Since the induced voltage in the receiving coil of the ACSM stress probe is in the millivolt range and is a differential signal, a high-precision differential instrumentation amplifier is required. The operational amplifier used in this embodiment needs to meet the requirements of low cost, low power consumption, high precision, small size, and low power consumption. For example, the operational amplifier could be AD620, INA351, etc. This embodiment does not limit the specific model of the operational amplifier; it only needs to meet the above requirements.

[0036] In this embodiment, the operational amplifier can be an AD620. The maximum supply current of the AD620 is 1.3mA; furthermore, the maximum nonlinear distortion of the AD620 is only 40ppm, the maximum offset voltage does not exceed 50μV, and the maximum offset drift is only 0.6uV / ℃, and its high precision characteristics perfectly meet the requirements of this design. Meanwhile, the settling time of the AD620 is only 15μs, making it particularly suitable for multi-channel data acquisition systems. The peripheral circuit structure of the AD620 is simple, requiring only one external resistor to control the gain. According to its design principle, the expression for its gain G and the external gain control resistor Rg is: G = 49.4K / Rg + 1, where Rg is the resistance value of the external gain control resistor. Calculated from the above formula, the adjustable gain range of the AD620 is 594 to 1263, which can meet the amplification requirements of the detection system for weak signals.

[0037] In some embodiments, the operational amplifier can be an INA351; the INA351 has a maximum supply current of 135μA; it supports a shutdown pin, reducing the current to the μA level when idle, significantly extending battery life, and features an ultra-small package (e.g., 10-pin X2QFN (1.5mm × 2mm), 8-pin WSON (2mm × 2mm), 8-pin SOT23-THN (4.64mm²)), and requires no external resistors, with integrated internal precision matching resistors (temperature drift <5ppm / ℃), avoiding the complexity of requiring external high-precision resistors, enabling applications that achieve medium-precision signal amplification within limited space and power consumption.

[0038] The processor is used to process the received stress characterization signal using an optimized JA model (Jiles-Atherton model) that makes explicit the implicit equations that originally characterize the change of magnetization or magnetic induction intensity with stress, and to calculate the stress of the tested magnetic object.

[0039] The beneficial effects of the AC electromagnetic field stress detection system disclosed herein are as follows:

[0040] When a periodically changing electric field is generated on the magnetic object being measured, an induced electric field similar to that of the excitation coil is generated inside the induction coil of the ACSM stress probe. When there is stress concentration on the object being measured, the magnetic permeability of the material changes, which in turn causes a change in the intensity of the induced electromotive force of the induction coil. After this signal is amplified, it is easier for the processor to extract the stress characterization signal. The processor uses an optimized JA model that makes the implicit equation that originally characterized the change of magnetization or magnetic induction intensity with stress explicit. Under the condition of determining the initial magnetization intensity of the ferromagnetic material and the intensity of the external magnetic field, it can accurately characterize the relationship between the magnetic field and stress on the surface of the object being measured without stress loading history, including the elastic and plastic stages of the material. This can improve the detection accuracy and is suitable for stress detection in oil and gas pipelines.

[0041] In some embodiments, in the above technical solutions, the process of obtaining the optimized JA model includes:

[0042] An optimized JA model is obtained by using a polynomial fitting method.

[0043] In some embodiments, in the above technical solution, the optimized JA model is: M = ax 7 +bx 6 +cx 5 +dx 4 +ex 3 +fx 2 +gx+h, M represents magnetization, x represents stress, a=-1.313×10 -51 b = 1.036 × 10 -42 c = -3.26 × 10 -34 d = 5.138 × 10 -26 e = -4.092 × 10 -18 f = 1.346 × 10 -10 g = -1.342 × 10 -4 h = -49.31.

[0044] The optimized JA model improves the accuracy of predicting the hysteresis behavior of ferromagnetic materials through temperature factor correction, loss mechanism extension, intelligent parameter identification, and wideband adaptation.

[0045] The process of building an optimized JA model is as follows:

[0046] First, by using data from the elastic and plastic phases, we analyze the applicability and advantages and disadvantages of the existing JA model.

[0047] Then, this disclosure proposes an optimized JA model using a polynomial fitting method, which makes the implicit equations that originally characterized the change of magnetization intensity M or magnetic induction intensity B with stress explicit. Under the condition of determining the initial magnetization intensity of the ferromagnetic material and the intensity of the external magnetic field, it can accurately characterize the relationship between the magnetic field and stress on the sample surface without stress loading history, including the elastic stage and the plastic stage of the material.

[0048] The JA model is the mainstream magnetization model describing the hysteresis phenomenon of ferromagnetic materials. It can reflect both macroscopic magnetization phenomena and calculate microscopic energy loss changes, thus gaining wide application. The optimized JA model mainly makes explicit the implicit equation of magnetization intensity M or magnetic induction intensity B as a function of stress, that is, establishing a corresponding relationship between the independent variable stress characteristic quantity and the dependent variable magnetization intensity M or magnetic induction intensity B. Conventional JA models only describe the hysteresis loop and lack intuitive descriptions of the relevant stress characteristic quantities. In addition, in the polynomial, the coefficient values ​​are fixed due to the constraints of the detected material and the excitation form. These fixed values ​​change with the detection material and excitation conditions, which is not limited in the embodiments of this disclosure.

[0049] In some embodiments, the above technical solution further includes a power amplification module, and the excitation signal generation module is a DDS (Direct Digital Synthesizer) chip. The sinusoidal AC signal generated by the DDS chip is amplified by the power amplification module and then applied to the excitation coil of the ACSM stress probe, as shown in Figures 2 and 3.

[0050] The main function of the excitation signal generation module is to provide a sinusoidal excitation signal of a certain frequency to the excitation coil of the detection probe. This disclosure uses a DDS (Direct Digital Synthesizer) chip to realize the sinusoidal excitation signal of the required frequency for the detection system. Compared with traditional excitation signal synthesizers, DDS has advantages in terms of low cost, low power consumption, high resolution, and high conversion efficiency. The basic theory of DDS technology is based on the time-domain sampling theorem. Its basic principle is to sample the sinusoidal signal to obtain a large amount of phase information related to it, then analyze and calculate this phase information to obtain the corresponding amplitude information, and after smoothing and filtering, the required signal can be output. The internal functional modules of DDS mainly include a phase accumulator, a function table, and a digital-to-analog converter.

[0051] The DDS chip used in this disclosure is a low-power DDS chip (e.g., AD9833, AD9834, AD9837, AD9838). This disclosure does not limit the specific model of the DDS chip, as long as it meets the requirement of low power consumption. In some embodiments, the DDS chip can be the AD9833. The AD9833 has the advantages of a small size and +5V DC power supply, featuring a 10-pin MSOP surface-mount package. The AD9833 includes two frequency registers and two phase registers, and its analog output is: fMCLK / 228×FREQEG, where FREQEG is the frequency word in the selected frequency register. This signal is phase-shifted by: 2π / 4096×PHASEREC, where PHASEREC is the phase word in the selected phase register. The AD9833 requires no external components. Both the output frequency and phase can be programmed via software and are easy to adjust. The frequency register is 28-bit. When the main clock frequency is 25MHz, the accuracy is 0.1Hz. When the main clock frequency is 1MHz, the accuracy can reach 0.004Hz, as shown in Figure 3.

[0052] Because the sinusoidal excitation signal provided by the AD9833 to the probe excitation coil has too weak a driving capability to directly drive the excitation coil, it must be driven by a power amplifier to have the ability to drive a load. The signal is amplified by a power amplifier module. For the power amplifier circuit, this disclosure uses a wideband high-performance operational amplifier that needs to have a very wide unit bandwidth and meet the power amplifier requirements of the excitation signal module.

[0053] In some embodiments, the broadband high-performance operational amplifier used in the present disclosure may be OPA548, OPA549, LM675, etc. In some embodiments, the broadband high-performance operational amplifier is OPA548.

[0054] In some embodiments, in the above technical solution, the A / D conversion circuit includes multiple conversion channels, the resolution of the A / D conversion circuit is not less than 1 bit, and the A / D conversion circuit has a high-speed digital-to-analog transmission interface.

[0055] In the AC electromagnetic field stress detection system (also known as the ACSM detection system) disclosed herein, the A / D conversion circuit is responsible for converting the detection signal from an analog signal to a digital signal, so that the ARM processor can perform corresponding data processing on the detection signal. The essential function of the A / D conversion circuit is to encode the voltage value of the detection signal and convert it into a digital quantity. The A / D converter is the core component of the signal acquisition circuit of the entire detection system, and its performance greatly affects the accuracy and power consumption of the entire signal acquisition circuit.

[0056] The requirements of this disclosure for the A / D conversion circuit mainly include the following points: (1) It can acquire at least three stress detection signals at the same time, and the conversion circuit has at least three conversion channels; (2) The amplitude of the detection signal is small, and the resolution of the analog-to-digital converter should not be less than 1 bit; (3) The amount of acquired signal data is large, and the real-time requirements are high, requiring the analog-to-digital converter to have a high-speed digital-to-analog transmission interface.

[0057] When the AC electromagnetic field stress detection system disclosed herein is working, the excitation signal generation module needs to generate a sinusoidal AC signal, which is then amplified by the power amplification module and applied to the excitation coil (excitation inductor coil) of the ACSM stress probe, creating a periodically changing electric field on the magnetic object being tested. Under normal circumstances, the induction coil of the probe will generate an induced electric field similar to that of the excitation coil. When there is stress concentration in the object being tested, the permeability of the material will change, which will in turn cause a change in the intensity of the induced electromotive force of the induction coil. This signal is amplified by the amplification and filtering circuit, converted into a digital signal by the ADC chip, picked up by the main control chip, and then forwarded to the host computer for data reading and display, thereby realizing the indirect detection of stress changes in the object being tested.

[0058] The hardware circuit of the AC electromagnetic field stress detection system disclosed herein includes several main parts such as a probe module, a signal conditioning module, an A / D conversion module, an excitation signal generation module, a main control module, and a differential signal transmission module.

[0059] A stress probe was mounted on a 508 magnetic flux leakage detector for testing. Power was supplied to the detector via traction, and an ACSM sensor was placed around the detector's magnetic flux leakage joint to test the sensor's detection performance in an actual pipeline.

[0060] The tensile testing platform mainly consists of three parts: a traction system, a simulated pipeline, and a stress loading device. Details are as follows.

[0061] A. Traction system:

[0062] In oil and gas pipelines, non-destructive testing (NDT) devices operate within the pipeline using the power of the transported medium to detect corrosion defects. Therefore, in the tension testing platform of the NDT device, the traction automatic control system, which mimics the power of the transported medium, is a crucial component. The transmission device, in particular, is the core of this traction automatic control system, and its operating speed significantly impacts the magnetic flux leakage detection signal.

[0063] Because of their advantages such as simple structure, flexible handling and installation, easy maintenance, convenient operation, low price, and high reliability, winches are widely used in material lifting, horizontal or inclined traction of heavy objects, piling, timber collection, cold drawing of steel bars, equipment installation, and other work. Therefore, in this traction automatic control system, a winch is selected for horizontal traction.

[0064] B. Simulated Pipeline:

[0065] Considering the test site and requirements, the piping used in the test system does not need to withstand high transmission pressure, toughness requirements, corrosion, or other factors; and based on the dimensions of the internal detector design, the main test piping selected for the test system is... Steel pipe (e.g., material: Q235B). The detector tests a self-built 20-inch spiral welded steel pipe with an outer diameter of 508mm, an inner diameter of 488mm, a wall thickness of 10mm, and a total length of 24m. At a length of 18m, an 80kN radial force is applied to make the axial local stress of the pipe reach 100MPa.

[0066] The test pipeline consisted of three complete pipes connected to a half-pipe, forming the entire test pipeline; a reducing cylinder was designed at the launch and receiver ends. Pipeline; the connection between the pipeline and the reducing cylinder is made by welding; the winch wire rope is kept on the same horizontal line as the center line of the test pipeline.

[0067] C. Stress loading device:

[0068] Finite element simulation showed that applying a radial force of approximately 80 kN to the pipeline could induce an axial stress of 100 MPa in a localized area. An IPC-20RS claw hydraulic jack with a total lifting height of 158 mm and a maximum lifting load of 200 kN was selected, meeting the experimental requirements. A self-made clamp was used to connect the jack to the pipeline, preventing safety accidents caused by angular deviations between the force-bearing surface and the hydraulic rod.

[0069] Using the fabricated sensors and data acquisition system, experiments were conducted to verify the overall detection capability and construct force-magnetic relationship curves. The experimental equipment included: sensors, electronic data acquisition system, test specimen, tensile loading platform, and computer equipment (e.g., tablet, computer with wireless transceiver capabilities, etc.).

[0070] The data obtained through the experiment are shown in Table 1:

[0071] Table 1:

[0072] Since the initial baseline values ​​of different sensors are slightly different, the test data were processed and the changes in sensor values ​​were calculated, as shown in Table 2.

[0073] Table 2:

[0074] To determine the force-magnetic relationship curve corresponding to the sensor, the data was fitted to obtain the fitted curve, and the fitting parameters are shown in Table 3.

[0075] Table 3:

[0076] As can be seen from Table 3, the coefficient B2 is very small. When B2 is considered to be 0, the entire curve is approximately a linear function with a slope of 3.05923 ± 0.10249.

[0077] The above experiments show that the sensor performance meets the requirements for rapid online detection of stress concentration areas of ±20MPa axial stress in the pipeline body when mounted on a pipeline robot carrier.

[0078] In the above embodiments, although the steps are numbered S1, S2, etc., they are only specific embodiments given in this disclosure. Those skilled in the art can adjust the execution order of S1, S2, etc. according to the actual situation, which is also within the protection scope of this disclosure. It can be understood that in some embodiments, some or all of the above embodiments may be included.

[0079] As shown in Figure 4, an embodiment of the present disclosure provides a method for detecting AC electromagnetic field stress. This includes steps S1 to S3.

[0080] S1. The excitation signal generation module applies a sinusoidal AC signal to the excitation coil of the ACSM stress probe to generate a periodically changing electric field on the magnetic object under test.

[0081] S2, the ACSM stress probe will send the stress characterization signal detected by the magnetic object under test to the processor after passing through the signal amplification circuit and the A / D conversion circuit in sequence;

[0082] S3. The processor uses an optimized JA model that makes explicit the implicit equations that originally characterize the change of magnetization or magnetic induction intensity with stress. It processes the received stress characterization signal and calculates the stress of the tested magnetic object.

[0083] In some embodiments, in the above technical solutions, the process of obtaining the optimized JA model includes:

[0084] An optimized JA model is obtained by using a polynomial fitting method.

[0085] In some embodiments, in the above technical solution, the optimized JA model is: M = ax 7 +bx 6 +cx 5 +dx4 +ex 3 +fx 2 +gx+h, M represents magnetization, x represents stress, a=-1.313×10 -51 b = 1.036 × 10 -42 c = -3.26 × 10 -34 d = 5.138 × 10 -26 e = -4.092 × 10 -18 f = 1.346 × 10 -10 g = -1.342 × 10 -4 h = -49.31.

[0086] In some embodiments, in the above technical solution, the excitation signal generation module is a DDS chip, and the sinusoidal AC signal generated by the DDS chip is amplified by a power amplifier module and then applied to the excitation coil of the ACSM stress probe.

[0087] In some embodiments, in the above technical solution, the A / D conversion circuit includes multiple conversion channels, the resolution of the A / D conversion circuit is not less than 1 bit, and the A / D conversion circuit has a high-speed digital-to-analog transmission interface.

[0088] Those skilled in the art will recognize that this disclosure can be implemented as a system, method, or computer program product. Therefore, this disclosure can be implemented as entirely hardware, entirely software (including firmware, resident software, microcode, etc.), or a combination of hardware and software, generally referred to herein as a "circuit," "module," or "system." Furthermore, in some embodiments, this disclosure can also be implemented as a computer program product contained in one or more computer-readable media, which includes computer-readable program code.

[0089] Any combination of one or more computer-readable media can be used. A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. The readable storage medium includes non-transitory computer-readable storage media. A computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More detailed examples (a non-exhaustive list) of computer-readable storage media include: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this disclosure, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0090] Although embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present disclosure.

Claims

1. An AC electromagnetic field stress detection system, comprising: Excitation signal generation module, AC electromagnetic field stress measurement ACSM stress probe, signal amplification circuit, analog-to-digital A / D conversion circuit and processor; The excitation signal generation module is used to: load a sinusoidal AC signal onto the excitation coil of the ACSM stress probe to generate a periodically changing electric field on the magnetic object under test; The ACSM stress probe is used to: transmit the stress characterization signal detected on the magnetic object under test to the processor after passing it sequentially through the signal amplification circuit and the A / D conversion circuit; The processor is used to: process the received stress characterization signal using an optimized JA model that makes explicit the implicit equations that originally characterize the change of magnetization or magnetic induction intensity with stress, and calculate the stress of the tested magnetic object.

2. The AC electromagnetic field stress detection system according to claim 1, wherein, The process of obtaining the optimized JA model includes: The optimized JA model is obtained by using a polynomial fitting method.

3. The AC electromagnetic field stress detection system according to claim 2, wherein, The optimized JA model is: M = ax 7 +bx 6 +cx 5 +dx 4 +ex 3 +fx 2 +gx+h, where M represents magnetization, x represents stress, and a = -1.313 × 10⁻⁶. -51 b = 1.036 × 10 -42 c = -3.26 × 10 -34 d = 5.138 × 10 -26 e = -4.092 × 10 -18 f = 1.346 × 10 -10 g = -1.342 × 10 -4 h = -49.

31.

4. The AC electromagnetic field stress detection system according to any one of claims 1 to 3 further includes a power amplification module, wherein the excitation signal generation module is a direct digital frequency synthesizer (DDS) chip, and the sinusoidal AC signal generated by the DDS chip is applied to the excitation coil of the ACSM stress probe after passing through the power amplification module.

5. The AC electromagnetic field stress detection system according to any one of claims 1 to 3, wherein, The A / D conversion circuit includes multiple conversion channels, the resolution of the A / D conversion circuit is not less than 1 bit, and the A / D conversion circuit has a high-speed digital-to-analog transmission interface.

6. A method for detecting stress in an alternating electromagnetic field, comprising: The excitation signal generation module loads a sinusoidal AC signal onto the excitation coil of the AC electromagnetic field stress measurement ACSM stress probe to generate a periodically changing electric field on the magnetic object under test. The ACSM stress probe transmits the stress characterization signal detected by the magnetic object under test to the processor after passing it through a signal amplification circuit and an analog-to-digital (A / D) conversion circuit in sequence. The processor uses an optimized JA model that makes explicit the implicit equations that originally characterize the change of magnetization or magnetic induction intensity with stress, to process the received stress characterization signal and calculate the stress of the tested magnetic object.

7. The AC electromagnetic field stress detection method according to claim 6, wherein, The process of obtaining the optimized JA model includes: The optimized JA model is obtained by using a polynomial fitting method.

8. The AC electromagnetic field stress detection method according to claim 7, wherein, The optimized JA model is: M = ax 7 +bx 6 +cx 5 +dx 4 +ex 3 +fx 2 +gx+h, where M represents magnetization, x represents stress, and a = -1.313 × 10⁻⁶. -51 b = 1.036 × 10 -42 c = -3.26 × 10 -34 d = 5.138 × 10 -26 e = -4.092 × 10 -18 f = 1.346 × 10 -10 g = -1.342 × 10 -4 h = -49.

31.

9. The AC electromagnetic field stress detection method according to any one of claims 6 to 8, wherein, The excitation signal generation module is a Direct Digital Synthesizer (DDS) chip. The sinusoidal AC signal generated by the DDS chip is amplified by a power amplifier module and then applied to the excitation coil of the ACSM stress probe.

10. The AC electromagnetic field stress detection method according to any one of claims 6 to 8, wherein, The A / D conversion circuit includes multiple conversion channels, the resolution of the A / D conversion circuit is not less than 1 bit, and the A / D conversion circuit has a high-speed digital-to-analog transmission interface.

11. A computer-readable storage medium comprising a computer program or instructions, wherein, When the computer program or instructions are run on a computer, the computer causes the computer to perform the method according to any one of claims 6 to 10.

12. A computer program product comprising computer instructions that, when executed by a processor, implement the method according to any one of claims 6 to 10.

13. A computer program comprising computer instructions that, when executed by a processor, implement the method according to any one of claims 6 to 10.

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