General excitation system and control method of electromagnetic flowmeter suitable for multi-aperture measurement

Abstract

This application relates to the field of electromagnetic flowmeter technology, and in particular to a universal excitation system and control method for electromagnetic flowmeters suitable for multi-diameter measurement. The excitation system includes an excitation coil, pole shoes, a magnetic yoke, an excitation power supply, and a processing module. When energized, the excitation coil generates a magnetic field perpendicular to the axis of the measuring pipe, covering the cross-section of the measuring pipe with a full target diameter. The pole shoes are located between the excitation coil and the outer wall of the measuring pipe. The magnetic yoke surrounds the excitation coil, forming a closed magnetic circuit with the excitation coil and pole shoes. The excitation power supply can dynamically adjust the magnitude and waveform of the excitation current according to the diameter of the measuring pipe. The processing module is responsible for controlling the output of the excitation power supply and calculating the flow rate of the measuring pipe. By introducing an excitation coil capable of covering a multi-diameter range and dynamically adjusting the excitation current and waveform, the magnetic field distribution and intensity can be optimized for different diameters, thereby achieving universality while ensuring the measurement accuracy of the electromagnetic flowmeter.

Description

Technical Field

[0001] This application relates to the field of electromagnetic flowmeter technology, and in particular to a universal excitation system and control method for electromagnetic flowmeters suitable for multi-diameter measurement. Background Technology

[0002] Electromagnetic flowmeters operate on the principle of electromagnetics: when fluid flows in a magnetic field, it generates an induced electromotive force proportional to the flow velocity. The flow rate of the fluid in the measured pipe is measured based on the electromotive force induced when a conductive fluid passes through an external magnetic field. The sensor converts the volume of fluid flowing through it into an electrical signal, which is then processed by a conversion circuit and displayed as a flow rate.

[0003] The specific measurement process is as follows: The converter outputs an excitation current, which generates a magnetic field B perpendicular to the central axis of the measuring tube through an excitation coil. The diameter of the measuring tube is D, and the liquid flow velocity inside the measuring tube is V. A pair of electrodes are installed on the side wall of the measuring tube. As the conductive fluid flows, electrons in the conductive fluid cut the magnetic field lines, producing a deflection perpendicular to both the direction of the magnetic field lines and the direction of motion. This generates a potential difference E between the electrodes that is proportional to the flow velocity. According to Faraday's law of magnetic induction: E = B × D × V, where B and D are constants, as long as the potential difference E between the electrodes is measured, the flow velocity V can be obtained, and thus the flow rate q = V × π × (0.5 × D) can be calculated. 2 =π×D×E / (4×k×B), where B, D, and k are all constants.

[0004] The existing technical solutions described above have the following drawbacks: Electromagnetic flowmeters generally adopt a "one diameter, one coil" design, meaning that for each diameter measuring tube, a specially designed and manufactured excitation coil matching the tube's size and magnetic circuit is required. This design leads to problems such as "high production costs, heavy inventory and management pressure, cumbersome maintenance, and resource waste." Therefore, a universal excitation system for electromagnetic flowmeters is needed to overcome the diameter limitation and achieve universality of the electromagnetic flowmeter excitation system. Summary of the Invention

[0005] In order to overcome the limitations of existing electromagnetic flowmeter diameters and realize the universality of electromagnetic flowmeter excitation systems, this application provides a universal excitation system and control method for electromagnetic flowmeters suitable for multi-diameter measurement.

[0006] The above-mentioned technical objective of this application is achieved through the following technical solution: A universal excitation system for electromagnetic flowmeters suitable for multi-diameter measurements includes an excitation coil for generating a magnetic field perpendicular to the central axis of the measuring tube when energized. The magnetic field can cover the cross-section of the measuring tube of the target diameter; The pole shoe is located between the excitation coil and the outer wall of the measuring tube and is used for magnetic conduction, magnetic focusing and field homogenization. The magnetic yoke is wrapped around the outside of the excitation coil and together with the excitation coil and pole shoes, forms a closed magnetic circuit. The excitation power supply, electrically connected to the excitation coil, is used to dynamically adjust the magnitude and waveform of the output excitation current according to the diameter of the measuring tube. The processing module controls the magnitude and waveform of the excitation current output by the excitation power supply according to the diameter of the measuring tube, and calculates the flow rate of the measuring tube.

[0007] By adopting the above scheme, and introducing a universal excitation coil, along with dynamic current adjustment of the excitation power supply and control and processing by the processing module, the excitation system can flexibly adapt to test tubes of different diameters, achieving universal measurement across multiple diameters. The excitation coil, pole shoes, and magnetic yoke together form the foundation of the magnetic circuit. The excitation power supply provides adjustable magnetic field excitation, while the processing module is responsible for the intelligent coordination and data processing of the entire system, ensuring accurate flow measurement results under different diameters. In this way, one excitation coil can cover multiple diameter ranges, achieving a "one-to-many" purpose, significantly reducing production costs, decreasing the types of spare parts, and simplifying management processes. By dynamically adjusting the excitation current and waveform, the excitation system can optimize the magnetic field distribution and intensity under different diameters, ensuring that the measurement accuracy is within an acceptable range, thus maintaining the core measurement performance of the electromagnetic flowmeter while achieving universality.

[0008] Furthermore, the excitation coil is elliptical; The excitation coil generates a uniform magnetic field in the central region; The magnetic field generated by the excitation coil is concentrated in the central region of the excitation coil.

[0009] Furthermore, the excitation coil covers a diameter range of DN15 to DN100; The excitation coil is wound uniformly; The number of turns of the excitation coil is optimized to form a magnetic field distribution curve with a wide plateau, which is used to expand the uniform magnetic field region.

[0010] Furthermore, the coil frame of the excitation coil is made of engineering plastic or composite material through one-time injection molding.

[0011] Furthermore, the processing module includes an identification unit and a signal processing unit; The identification unit is used to obtain the diameter of the measuring tube and transmit the obtained diameter to the signal processing unit; The signal processing unit controls the magnitude and waveform of the excitation current output by the excitation power supply based on the aperture information transmitted by the identification unit, and calculates the flow rate of the measuring tube through the electromotive force obtained from the electrodes.

[0012] Furthermore, the measuring tube is provided with a mechanical structure; Different diameter measuring tubes correspond to different mechanical structures; The identification unit obtains the diameter of the measuring tube by identifying different mechanical structures.

[0013] Furthermore, an electronic tag is installed on the measuring tube to store the diameter information of the measuring tube; The identification unit obtains the diameter of the measuring tube by reading the diameter information stored in the electronic tag.

[0014] Furthermore, a control method for the universal excitation system of an electromagnetic flowmeter applicable to multi-diameter measurements includes the following steps: The processing module obtains the diameter information of the measuring tube; The processing module controls the excitation power supply output to match the magnitude and waveform of the excitation current with the diameter of the measuring tube based on the obtained diameter information of the measuring tube. The processing module calculates the flow rate of the measuring tube.

[0015] Furthermore, the processing module includes an identification unit and a signal processing unit; The identification unit identifies the mechanical structure or electronic tag on the measuring tube to obtain or read the diameter information of the measuring tube; The identification unit transmits the obtained or read diameter information of the measuring tube to the signal processing unit; The signal processing unit receives the aperture information of the measuring tube and controls the excitation power supply to output an excitation current with a magnitude and waveform that matches the aperture of the measuring tube. The signal processing unit calculates the flow rate of the measuring tube.

[0016] Furthermore, the signal processing unit calculates the flow rate of the measuring tube using the following steps: The signal processing unit determines the mapping calibration parameters of the received aperture information based on the pre-stored calibration parameters and the received aperture information. The signal processing unit controls the excitation power supply output and the magnitude and waveform of the excitation current to match the diameter of the measuring tube according to the determined mapping calibration parameters; The signal processing unit receives the electromotive force information output by the electrode, processes it, and obtains the effective electromotive force. The signal processing unit calculates the flow rate based on the mapping calibration parameters and the effective electromotive force; The calibration parameters include the magnetic field strength compensation coefficient and the velocity-potential conversion coefficient.

[0017] In summary, this application has the following technical effects: 1. By introducing a universal excitation coil, coupled with dynamic current adjustment of the excitation power supply and control and processing by the processing module, the excitation system can flexibly adapt to test tubes of different diameters, achieving universal measurement across multiple diameters. In this way, one excitation coil can cover multiple diameter ranges, achieving a "one-to-many" solution, significantly reducing production costs, decreasing the types of spare parts, and simplifying management processes. By dynamically adjusting the excitation current and waveform, the excitation system can optimize the magnetic field distribution and intensity under different diameters, ensuring measurement accuracy within acceptable limits, thus maintaining the core measurement performance of the electromagnetic flowmeter while achieving universality.

[0018] 2. By incorporating a unique mechanical structure on the measuring tube and using an identification unit to recognize it, automated acquisition of the tube's diameter information is achieved. Alternatively, an electronic tag can be installed on the measuring tube, and the identification unit can read its stored diameter information. This automated, non-contact diameter identification method significantly improves the accuracy and reliability of diameter information acquisition, avoiding mismatches between the excitation current and the actual diameter caused by human input errors or inaccurate identification. Therefore, the excitation power supply can always output an excitation current precisely matched to the current measuring tube diameter, thus ensuring the accuracy and stability of flow measurement in multi-diameter measurement scenarios, and enhancing the system's intelligence and user experience.

[0019] 3. By introducing calibration parameters, the signal processing unit, upon receiving the diameter information of the measuring tube, can accurately determine the mapping calibration parameters for that diameter based on pre-stored calibration parameters. These mapping calibration parameters are used to finely control the magnitude and waveform of the excitation current output by the excitation power supply, ensuring that the magnetic field strength and distribution reach the optimal measurement state under different diameters. Simultaneously, during the flow calculation stage, the signal processing unit uses the processed effective electromotive force and these precise mapping calibration parameters for calculation. This mechanism, which introduces diameter-specific calibration parameters in both the excitation control and flow calculation stages, effectively compensates for the differences in magnetic field characteristics and flow velocity-potential conversion relationships between measuring tubes of different diameters, thereby significantly improving the accuracy and reliability of flow measurement in multi-diameter measurement scenarios. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the installation of the general excitation system for electromagnetic flowmeters in this application applied to a DN15 measuring tube; Figure 2 yes Figure 1 Sectional view at section AA; Figure 3 This is a schematic diagram of the installation of the general excitation system of the electromagnetic flowmeter in this application applied to a DN100 measuring tube; Figure 4 yes Figure 3 Sectional view at section BB; Figure 5 This is a system block diagram of the first embodiment of the universal excitation system for electromagnetic flowmeters in this application; Figure 6 This is a system block diagram of a second embodiment of the universal excitation system for electromagnetic flowmeters in this application; Figure 7 This is a flowchart of the control method for the universal excitation system of electromagnetic flowmeter applicable to multi-diameter measurement in this application; Figure 8 This is a flowchart illustrating the control method of the universal excitation system for electromagnetic flowmeters applicable to multi-diameter measurements in this application.

[0021] In the diagram, 1 is the measuring tube; 2 is the general excitation system; 21 is the excitation coil; 22 is the pole shoe; and 23 is the magnetic yoke. Detailed Implementation

[0022] The present application will be further described in detail below with reference to the accompanying drawings.

[0023] In the description of this specific embodiment, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this specific embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0024] In the description of this specific embodiment, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0025] In the manufacturing and application of electromagnetic flowmeters, the excitation coil must precisely correspond to the size and magnetic circuit parameters of the measuring tube 1. This results in the need for a dedicated excitation coil to be designed and manufactured for each type of measuring tube 1. This design pattern requires equipment parameter adjustments when switching between different diameter products on the production line, and the inventory management of multiple specifications of coils requires storage space. During maintenance, the replacement of the measuring tube 1 requires matching the corresponding coil, thus affecting key performance indicators such as production efficiency, inventory management efficiency, and ease of maintenance. For example: If we are currently deploying measuring tubes 1 with diameters of DN15 and DN100, and installing an electromagnetic flow meter, we must prepare dedicated excitation coils for DN15 and DN100 respectively. Since the coil specifications are incompatible, they cannot be interchanged between different diameters. During on-site installation, we need to carry multiple spare parts, and the logistics management process requires handling additional spare parts scheduling. During maintenance, if the DN15 measuring tube 1 is damaged and needs to be replaced, a dedicated DN15 coil must be used. Otherwise, an effective magnetic field cannot be established, causing the system to fail to output a flow signal normally.

[0026] Reference Figures 1-6 To address the aforementioned problems, this application provides a universal excitation system for electromagnetic flowmeters suitable for multi-diameter measurements. The system includes an excitation coil 21, pole shoes 22, a magnetic yoke 23, an excitation power supply, and a processing module. When energized, the excitation coil 21 generates a magnetic field perpendicular to the central axis of the measuring tube 1, capable of covering the cross-section of the measuring tube 1 for each target diameter. The pole shoes 22 are positioned between the excitation coil 21 and the outer wall of the measuring tube 1, serving for magnetic conduction, magnetic focusing, and field homogenization. The magnetic yoke 23 wraps around the excitation coil 21 and, together with the excitation coil 21 and pole shoes 22, forms a closed magnetic circuit. The excitation power supply is electrically connected to the excitation coil 21. The excitation power supply dynamically adjusts the magnitude and waveform of the output excitation current according to the diameter of the measuring tube 1. The processing module controls the magnitude and waveform of the excitation current output by the excitation power supply according to the diameter of the measuring tube 1 and calculates the flow rate of the measuring tube 1.

[0027] By introducing a universal excitation coil 21, combined with dynamic current adjustment of the excitation power supply and control and processing by the processing module, the universal excitation system 2 can flexibly adapt to test tubes of different diameters, achieving universal measurement across multiple diameters. In this way, one excitation coil 21 can cover multiple diameter ranges, achieving a "one-to-many" purpose, significantly reducing production costs, decreasing the types of spare parts, and simplifying management processes.

[0028] To facilitate understanding, further explanation is provided: In this embodiment, the excitation coil 21 is one of the core components of the excitation system. Its function is to generate a magnetic field perpendicular to the central axis of the measuring tube 1 when energized. This magnetic field is designed to cover the entire cross-section of the measuring tube 1 with the target diameter. For example, the excitation coil 21 can be formed by winding wires around a coil frame. In practical applications, the number of turns and size of the excitation coil 21 can be initially designed based on the expected magnetic field strength and coverage area. When fluid passes through the measuring tube 1, the magnetic field acts on the fluid, causing it to generate an induced electromotive force.

[0029] In this embodiment, the electromotive force (EMF) is the potential difference generated between electrodes due to charge separation when a conductive fluid moves in a magnetic field. The magnitude of the EMF is proportional to the fluid velocity. Free charged ions (positive and negative ions) in the fluid are deflected and accumulated towards both sides of the tube wall under the action of the Lorentz force. Typically, the excitation system 2 is equipped with two electrodes located on both sides of the measuring tube 1, directly collecting the potential difference accumulated on both sides to obtain the EMF.

[0030] In this embodiment, the pole piece 22 is disposed between the excitation coil 21 and the outer wall of the measuring tube 1. Its main function is to guide magnetic field lines, concentrate the magnetic field in the region of the measuring tube 1, and help to make the magnetic field uniformly distributed in this region. For example, the pole piece 22 can be made of one or more pieces of highly permeable magnetic material, and its shape can be designed to match the shape of the measuring tube 1 to optimize the transmission path of the magnetic field. Through the configuration of the pole piece 22, the magnetic field generated by the excitation coil 21 can be effectively guided into the interior of the measuring tube 1, improving the magnetic field utilization rate.

[0031] In this embodiment, the magnetic yoke 23 surrounds the excitation coil 21, forming a closed magnetic circuit together with the excitation coil 21 and the pole shoe 22. The magnetic yoke 23 is typically made of a high-permeability material, such as soft iron or silicon steel sheet. Its function is to provide a low-resistivity return path for the magnetic lines of force, thereby forming a complete magnetic loop, reducing magnetic flux leakage, and enhancing the stability of the magnetic field. For example, the magnetic yoke 23 can be designed as a U-shaped or E-shaped structure to surround the excitation coil 21 and the pole shoe 22, ensuring the efficient utilization of magnetic field energy.

[0032] In this embodiment, the excitation power supply can dynamically adjust the magnitude and waveform of the current output to the excitation coil 21 according to an external control signal to adapt to the measurement requirements of measuring tubes 1 with different diameters. The excitation power supply can be a programmable current source, and the amplitude and frequency of its output current can be adjusted by an external control signal. In one implementation, the excitation power supply can preset multiple current output levels and simple waveforms, and switch between different levels to adapt to measuring tubes 1 with different diameters. This dynamic adjustment capability allows the same set of excitation coils 21 to adapt to measuring tubes 1 of different sizes without the need to replace the excitation coils 21.

[0033] In this embodiment, the waveform of the excitation current includes a square wave or a dual-frequency wave. The square wave is primarily a low-frequency rectangular wave, which has advantages such as suppressed polarization, small zero-point drift, simple circuitry, and strong anti-interference capabilities. It is mainly used in applications involving clean water, water supply and drainage, or low-impurity liquids. The dual-frequency wave is a superposition of a low-frequency square wave and a high-frequency square wave. The low-frequency wave stabilizes the zero point, while the high-frequency wave suppresses noise from slurry flow. It is mainly suitable for complex operating conditions such as mineral slurry, paper pulp, sewage, and low-conductivity liquids. Of course, depending on the specific operating conditions, the waveform of the excitation power supply is not limited to these two types; other waveforms can also be used.

[0034] In this embodiment, two excitation coils 21, two pole shoes 22, and two magnetic yokes 23 are provided, symmetrically arranged on both sides of the measuring tube 1. This symmetrical arrangement is a typical structure of electromagnetic flowmeters, ensuring the uniformity and symmetry of the magnetic field across the cross-section of the measuring tube 1. The two excitation coils 21 are positioned opposite each other, generating magnetic fields with opposite directions but equal intensity, thereby forming a uniform magnetic field perpendicular to the fluid direction inside the measuring tube 1. The symmetrical arrangement of the pole shoes 22 and the magnetic yoke 23 further optimizes the closure of the magnetic circuit and the guidance of the magnetic flux, ensuring the strength and uniformity of the magnetic field.

[0035] Furthermore, the excitation coil 21 is elliptical, and it generates a uniform magnetic field in its central region. The magnetic field generated by the excitation coil 21 is concentrated in its central region.

[0036] In this embodiment, the excitation coil 21 has an unconventional geometric configuration designed to optimize the spatial distribution characteristics of the magnetic field. This elliptical excitation coil 21 can be achieved by winding wires onto a prefabricated elliptical frame, or by shaping a circular excitation coil 21 in a specific direction. Its core function is that, compared to circular or rectangular excitation coils 21, the elliptical excitation coil 21 can more effectively form a broad and uniform magnetic field in the central region, while concentrating magnetic field lines in this area, reducing energy loss caused by the outward diffusion of the magnetic field.

[0037] In this embodiment, the excitation coil 21 generates a highly uniform magnetic field in the central region, with the magnetic field strength and direction maintaining a high degree of consistency in space. This uniform magnetic field can be achieved by precisely designing the coil's turn distribution, winding method, and overall coil dimensions. For example, multi-layer winding or variable-pitch winding techniques can be employed. Furthermore, by combining the geometry and material properties of the pole shoes 22, the magnetic field lines can be effectively guided and shaped to further expand and optimize the uniform magnetic field region. This uniformity is crucial for ensuring a good linear relationship between the induced electromotive force and flow velocity when fluid passes through this region, thus directly affecting the accuracy of the measurement results.

[0038] In this embodiment, the magnetic field generated by the excitation coil 21 is concentrated in the central region of the excitation coil 21, meaning the magnetic field strength at the center of the excitation coil 21 is greater than that at its edges. This indicates that the magnetic field lines are mainly confined within the internal space of the excitation coil 21, particularly near its geometric center, while the outward-spreading magnetic field strength is relatively weak, resulting in a high-intensity magnetic field in the central region of the excitation coil 21. This concentration of the magnetic field helps improve magnetic field utilization, reduce magnetic field leakage, and thus enhance excitation efficiency and the strength of the measurement signal. The high-intensity magnetic field ensures that a sufficiently strong induced electromotive force can be generated even under conditions of low fluid conductivity or slow flow velocity, thereby guaranteeing the reliability and signal-to-noise ratio of the measurement signal.

[0039] When the excitation coil 21 is used for a smaller diameter measuring tube 1, the entire cross-section of the smaller diameter measuring tube 1 is located in the central magnetic field region. This means that for a smaller diameter measuring tube 1, its entire fluid channel can be completely covered by the high-intensity and uniform central magnetic field generated by the excitation coil 21. This complete coverage ensures the measurement accuracy of the small-diameter measuring tube 1 and avoids errors caused by uneven or insufficient magnetic field strength.

[0040] When the excitation coil 21 is used for the measuring tube 1 with the largest target diameter, the edge of the measuring tube 1 is located in the magnetic field strength attenuation region, and the attenuation degree is optimized to ensure that the measurement accuracy is within the allowable range. This allowable range is ±0.5%. For measuring tubes 1 with larger diameters, the central part remains in the uniform magnetic field region, but the edge extends to the region where the magnetic field strength begins to naturally attenuate. This attenuation is not random but carefully designed and optimized to ensure that even in the edge region, the magnetic field strength and uniformity meet certain accuracy requirements. For example, by adjusting the winding density of the excitation coil 21 or the shape of the pole shoe 22, the gradient of magnetic field attenuation can be controlled, keeping its impact on the overall measurement result within the allowable range of ±0.5%. This maximizes the magnetic field coverage of a single excitation coil 21 while ensuring measurement accuracy, achieving compatibility with measuring tubes 1 with larger diameters.

[0041] The universal excitation system 2 in this embodiment effectively solves the problem that traditional electromagnetic flowmeters struggle to balance magnetic field coverage, uniformity, and measurement accuracy when measuring multiple diameters. The design of the elliptical excitation coil 21 and the optimization of the magnetic field distribution ensure a stable and reliable magnetic field environment for measuring tubes 1 of different diameters. For small-diameter measuring tubes 1, the entire cross-section is in a high-intensity, uniform magnetic field, guaranteeing high-precision measurement. For large-diameter measuring tubes 1, even if the edge of the measuring tube 1 is located in the magnetic field attenuation region, the measurement accuracy can still be controlled within a strictly permissible range due to optimized attenuation. This significantly improves the versatility and measurement accuracy of the electromagnetic flowmeter in multi-diameter applications, avoiding the complexity and cost of equipping different excitation systems for different diameter measuring tubes 1.

[0042] In this embodiment, the coil frame of the excitation coil 21 is injection molded from engineering plastic or composite material in one step. Preferably, the coil frame can be injection molded from high-strength engineering plastic or composite material in one step. The coil frame of the excitation coil 21 is the supporting structure of the excitation coil 21, used to support the coil winding and ensure that the excitation coil 21 maintains the preset geometric shape and dimensional accuracy during operation. Its function is to provide mechanical support, electrical insulation, and thermal management to maintain the stable operation of the excitation coil 21 and the accuracy of the magnetic field output.

[0043] In this embodiment, engineering plastics refer to plastics with excellent comprehensive properties such as mechanical properties, heat resistance, corrosion resistance, and electrical insulation, such as polyamide, polycarbonate, polyphenylene sulfide, or polyetheretherketone. Composite materials are new materials formed by combining two or more materials with different properties through physical or chemical methods, such as glass fiber reinforced plastics or carbon fiber reinforced plastics, which typically have higher strength and stiffness. The selection of these materials aims to provide sufficient mechanical strength and stability for the coil frame to resist electromagnetic forces, thermal stress, and external mechanical impacts during operation.

[0044] In this embodiment, one-time injection molding involves injecting molten plastic or composite material into a mold cavity and then cooling and solidifying it in one step to form a part of the desired shape. This process enables the precise manufacturing of complex shapes and offers advantages such as high production efficiency, good product consistency, high dimensional accuracy, and the ability to integrate multiple functional structures. One-time injection molding ensures the integrity and structural strength of the coil frame, reduces assembly steps, and lowers manufacturing costs. Simultaneously, it further enhances the stiffness, creep resistance, and fatigue resistance of the coil frame, ensuring that the excitation coil 21 maintains its structural integrity and the stability of its magnetic field output even under more demanding operating environments.

[0045] In this embodiment, the excitation coil 21 is wound uniformly, and the number of turns of the excitation coil 21 is optimized to form a wide-platform magnetic field distribution curve, which is used to expand the uniform magnetic field region. Uniform winding means that the wires of the excitation coil 21 are wound in a regular, equally spaced manner on the coil frame. This winding method helps to form a more regular magnetic field distribution and is easy to automate production.

[0046] In this embodiment, by adjusting the winding turn density of the excitation coil 21 at different positions, the magnetic field strength in the central region of the excitation coil 21 remains relatively constant over a wide range, thereby expanding the uniform magnetic field region. This optimization can be designed using simulation tools such as finite element analysis, or achieved by experimentally adjusting the winding parameters.

[0047] In this embodiment, the excitation coil 21 is wound with high-temperature resistant enameled wire and then subjected to overall vacuum impregnation treatment. High-temperature resistant enameled wire refers to insulated wire with a high heat resistance rating, such as H-class or F-class insulated enameled wire, which can withstand high operating temperatures without damaging the insulation layer, thereby improving the reliability and service life of the excitation coil 21. Overall vacuum impregnation treatment refers to immersing the insulating varnish into the wound coil in a vacuum environment and then curing it. This treatment method can effectively fill the tiny gaps inside the coil, improving the coil's insulation performance, moisture resistance, mechanical strength, and heat dissipation capacity, further enhancing the coil's durability and stability.

[0048] In this embodiment, the excitation coil 21 covers a diameter range from DN15 to DN100, indicating that the universal excitation system 2 of this application is designed to be compatible with a variety of measuring tube 1 diameters from 15 mm to 100 mm. This wide diameter coverage capability is key to achieving versatility, requiring the universal excitation system 2 to provide a stable and effective magnetic field for measuring tubes 1 of different sizes.

[0049] By designing the number of turns and winding method of the excitation coil 21, and combining this with its unconventional shape, the magnetic field strength in the central region of the excitation coil 21 remains highly uniform across a wide lateral range, effectively expanding the uniform magnetic field area. This wide-platform magnetic field distribution allows a single excitation system to better adapt to a wide diameter range from DN15 to DN100, ensuring that even the fluid cross-section of a larger diameter measuring tube 1 is fully covered by the uniform magnetic field, thus guaranteeing measurement accuracy. Simultaneously, the use of high-temperature resistant enameled wire and overall vacuum impregnation treatment greatly enhances the heat resistance, insulation, and mechanical strength of the excitation coil 21, enabling it to maintain stable performance under harsh operating conditions, significantly extending the equipment's service life and reducing maintenance costs.

[0050] In this embodiment, the processing module is the control and calculation center of the system. It is responsible for controlling the output of the excitation power supply according to the diameter information of the measuring tube 1, and receiving the electromotive force signal induced by the electrodes, and then calculating the fluid flow rate through the measuring tube 1.

[0051] Specifically, the processing module includes an identification unit and a signal processing unit. The identification unit is responsible for acquiring the diameter information of the measuring tube 1. The identification unit is a key front-end component for the system to achieve multi-diameter adaptive operation, ensuring the accuracy of subsequent signal processing.

[0052] In one implementation, the measuring tube 1 is provided with a mechanical structure, and different diameter measuring tubes 1 correspond to different mechanical structures. The identification unit obtains the diameter of the measuring tube 1 by identifying the different mechanical structures.

[0053] In this embodiment, the mechanical structure refers to a physically identifiable feature formed at a specific location on the measuring tube 1, such as its connecting end or outer wall. These features can be geometric shapes, sizes, arrangements, or combinations thereof, and their main purpose is to serve as a physical code for uniquely identifying or distinguishing measuring tubes 1 of different diameters. The design of this mechanical structure should take into account its durability during installation and use, ease of identification, and compatibility with the overall structure of the measuring tube 1.

[0054] For example, the mechanical structure can be a protrusion or a groove. A protrusion refers to an upward-projecting part on the surface of the measuring tube 1, such as a pin, bump, rib, or a flange of a specific shape. A groove refers to a downward-recessed part on the surface of the measuring tube 1, such as a notch, hole, pit, or a recessed area of ​​a specific shape. Protrusions and grooves can be used individually or in combination, and different caliber information can be encoded by variations in their number, arrangement, relative position, or geometric dimensions.

[0055] To enable the system to distinguish between measuring tubes 1 of different diameters, a clear correspondence needs to be established, meaning that each specific diameter measuring tube 1 has its own unique mechanical structure. This correspondence can be a pre-defined encoding rule, for example, using the number, location, shape, or combination of mechanical structures to represent different diameter values. For instance, one mechanical structure can be designed for a DN15 diameter measuring tube 1, another for a DN25 diameter measuring tube 1, and so on, ensuring that each diameter has its unique physical identifier. The identification unit, part of the processing module, functions to detect and parse the diameter information carried by the mechanical structure on the measuring tube 1. The identification process typically involves physical contact or non-contact sensing between the identification unit and the mechanical structure. For example, the identification unit can contain a series of sensors capable of detecting the presence, location, or shape of the mechanical structure and converting these physical signals into electrical signals. These electrical signals are then processed by the logic circuitry or microprocessor within the identification unit to decode the corresponding measuring tube 1 diameter information. The obtained diameter information is then transmitted to the signal processing unit. Based on this aperture information, the signal processing unit precisely controls the magnitude and waveform of the excitation current output to match the current aperture of the measuring tube 1.

[0056] In one specific implementation, a series of grooves can be provided at the connecting flange or interface of the measuring tube 1. For example, for measuring tubes 1 with different diameters such as DN15, DN25, DN50, and DN100, different numbers of grooves can be provided at specific circumferential positions on the flange. For example, a DN15 measuring tube 1 can have one groove, a DN25 measuring tube 1 can have two grooves, a DN50 measuring tube 1 can have three grooves, and a DN100 measuring tube 1 can have four grooves. The identification unit can integrate an array of multiple photoelectric sensors or microswitches, which are precisely arranged at the groove positions on the flange of the measuring tube 1. For example, if a groove is detected at the first position and not at other positions, the identification unit determines that the current diameter of the measuring tube 1 is DN15. If grooves are detected at the first two positions, it is determined to be DN25, and so on. The identification unit sends this identification result to the signal processing unit, which then adjusts the output parameters of the excitation power supply.

[0057] In another implementation, an electronic tag is installed on the measuring tube 1, and the electronic tag stores the diameter information of the measuring tube 1. The identification unit obtains the diameter of the measuring tube 1 by reading the diameter information stored in the electronic tag. The electronic tag is a device capable of storing data and conducting wireless communication. It can employ radio frequency identification (RFID) technology for contactless data exchange with the reading device via radio frequency signals; or near field communication (NFC) technology for data transmission between devices over short distances; or a QR code. The storage medium inside the electronic tag is pre-written with or written with the specific diameter data of the measuring tube 1 during installation. This diameter information can be standardized values, such as DN15, DN25, DN50, and DN100, or other codes that uniquely identify the size of the measuring tube 1.

[0058] The identification unit is equipped with a corresponding reader or radio frequency technology. The reader can emit radio frequency signals to activate the electronic tag and receive the data signals returned by the electronic tag. When the measuring tube 1 is installed in the excitation system or within the sensing range of the identification unit, the reader of the identification unit can automatically establish communication with the electronic tag on the measuring tube 1 and parse the stored diameter information. Through this non-contact, automated reading method, the identification unit can accurately obtain the current diameter of the measuring tube 1.

[0059] In one specific implementation, a passive RFID tag can be embedded or affixed to the outer wall of the measuring tube 1, for example, in the area near the excitation coil 21. This tag is pre-programmed with the diameter information of the measuring tube 1, such as "DN50". The identification unit can integrate an RFID reading module, which automatically transmits a radio frequency signal towards the measuring tube 1 when the system starts or when a replacement of the measuring tube 1 is detected. When the RFID tag enters the effective sensing range of the reading module, it is activated by radio frequency energy and transmits its stored "DN50" diameter information back to the reading module via radio waves. Upon receiving this information, the identification unit parses it and transmits it to the signal processing unit. Based on the received "DN50" diameter information, the signal processing unit looks up the corresponding excitation current magnitude and waveform parameters from a preset parameter table and instructs the excitation power supply to output the corresponding excitation current.

[0060] By incorporating a unique mechanical structure on measuring tube 1 and using an identification unit to recognize it, the diameter information of measuring tube 1 is automatically acquired. Alternatively, an electronic tag can be installed on measuring tube 1, and the identification unit can read the stored diameter information. This automated, non-contact diameter identification method significantly improves the accuracy and reliability of diameter information acquisition, avoiding mismatches between the excitation current and the actual diameter caused by human input errors or inaccurate identification. The excitation power supply can always output an excitation current that precisely matches the current diameter of measuring tube 1, thereby ensuring the accuracy and stability of flow measurement in multi-diameter measurement scenarios, and improving the system's intelligence level and user experience.

[0061] In this embodiment, the signal processing unit is responsible for receiving the aperture information transmitted by the identification unit and making decisions and controls based on this information. It can be implemented as a microcontroller, digital signal processor, or field-programmable gate array, embedding corresponding control algorithms and flow calculation models. The signal processing unit is responsible for adjusting the excitation strategy according to the aperture information and completing the final flow calculation.

[0062] Specifically, after obtaining the diameter of measuring tube 1, the identification unit transmits this information to the signal processing unit. This transmission can be via a wired or wireless communication interface, such as a Serial Peripheral Interface (SPI), I2C bus, Universal Asynchronous Receiver / Transmitter (UART), or a higher-speed Ethernet interface. Based on the diameter information transmitted by the identification unit, the signal processing unit controls the magnitude and waveform of the excitation current output by the excitation power supply and calculates the flow rate of measuring tube 1 using the electromotive force derived from the electrodes. Furthermore, based on the received diameter information, the signal processing unit consults a preset parameter table or executes a specific algorithm to determine the appropriate excitation current magnitude and waveform for the current diameter and issues control commands to the excitation power supply. For example, the signal processing unit communicates with the excitation power supply via a digital-to-analog converter (DAC) or pulse-width modulation (PWM) signal to precisely control the amplitude, frequency, and waveform of the excitation current, thereby optimizing the magnetic field distribution and measurement signal quality. The signal processing unit receives the electromotive force signal from the electrode, performs filtering, amplification, analog-to-digital conversion and other processing on the signal, and then combines the current diameter information and excitation parameters to calculate the flow rate of measuring tube 1 using the flow calculation formula.

[0063] When used with small-diameter pipes, a lower current is employed to save energy; when used with large-diameter pipes, the current is automatically increased to compensate for signal attenuation that may occur due to the increased magnetic field coverage. Specifically, for small-diameter measuring tube 1, due to its smaller cross-section, a relatively lower magnetic field strength is required to ensure measurement accuracy; therefore, using a lower excitation current can effectively reduce energy consumption. For large-diameter measuring tube 1, in order to ensure that the magnetic field can fully cover the entire cross-section of measuring tube 1 and maintain sufficient magnetic field strength to avoid attenuation of the induced electromotive force signal due to the increased magnetic field coverage, the signal processing unit automatically increases the excitation current, thereby ensuring accuracy and signal-to-noise ratio during large-diameter measurements. This collaborative and adaptive excitation current control strategy allows the entire electromagnetic flowmeter system to flexibly respond to the measurement needs of different diameters, optimizing energy utilization efficiency while ensuring measurement accuracy.

[0064] Through a universal physical structure of excitation coil 21, pole shoe 22, and magnetic yoke 23, combined with dynamic current adjustment of the excitation power supply and intelligent control and calculation of the processing module, the system can flexibly adapt to different diameter measuring tubes 1 without replacing the core excitation coil 21 when the diameter of the measuring tube 1 changes, thus achieving universal multi-diameter measurement. The excitation coil 21, pole shoe 22, and magnetic yoke 23 together form the foundation of the magnetic circuit, the excitation power supply provides adjustable magnetic field excitation, and the processing module is responsible for the intelligent coordination and data processing of the entire system, ensuring accurate flow measurement results can be obtained under different diameters.

[0065] By setting a unique mechanical structure on measuring tube 1 and using an identification unit to identify it, the diameter information of measuring tube 1 is automatically acquired, or an electronic tag is installed on measuring tube 1 and its stored diameter information is read by the identification unit. This ensures that the excitation system can adaptively adjust according to the actual diameter of measuring tube 1, guaranteeing measurement accuracy and efficiency in multi-diameter measurement scenarios.

[0066] Reference Figures 7-8 In another embodiment, a control method for a universal excitation system of an electromagnetic flowmeter suitable for multi-diameter measurement is provided, comprising the following steps: The processing module obtains the diameter information of measuring tube 1; The processing module controls the excitation power supply to output an excitation current of a size and waveform that matches the diameter of the measuring tube 1, based on the obtained diameter information of the measuring tube 1. The processing module calculates the flow rate of measuring tube 1.

[0067] By dynamically acquiring the diameter information of the measuring tube 1 through the processing module and adjusting the excitation current parameters accordingly, the traditional physical limitation of "one coil per diameter" is overcome, enabling adaptive control and measurement of multi-diameter measuring tubes 1 by a single universal excitation system 2. Specifically, when the processing module identifies measuring tubes 1 with different diameters, it can automatically optimize the magnitude and waveform of the excitation current. For example, a lower current is used for smaller diameters to save energy, while the current is increased for larger diameters to compensate for signal attenuation that may occur due to the increased magnetic field coverage, ensuring that the measurement accuracy is within the allowable range. This dynamic adjustment mechanism avoids the need to design a separate excitation coil 21 for each diameter, significantly reducing production costs, simplifying inventory management, and reducing maintenance complexity.

[0068] The electromagnetic flowmeter in this embodiment can flexibly adapt to various measuring pipes 1 with diameters ranging from DN15 to DN100 without replacing other components such as the excitation coil 21. Through intelligent control, the dynamic current adjustment mechanism is combined with multi-diameter adaptation logic, enabling the universal excitation system to achieve high-precision flow measurement in the DN15 to DN100 diameter range. At the same time, the magnetic field distribution curve is optimized to expand the uniform magnetic field area, significantly improving resource utilization efficiency and system maintenance convenience.

[0069] Specifically, the processing module controls the excitation power supply output to match the magnitude and waveform of the excitation current with the diameter of the measuring tube 1, based on the obtained diameter information of the measuring tube 1, including the following steps: The identification unit identifies the mechanical structure or electronic tag on the measuring tube 1 to obtain or read the diameter information of the measuring tube 1; The identification unit transmits the obtained or read diameter information of the measuring tube 1 to the signal processing unit; The signal processing unit receives the aperture information of the measuring tube 1 and controls the excitation power supply to output an excitation current with a magnitude and waveform that matches the aperture of the measuring tube 1.

[0070] In this embodiment, an example is given: when an electromagnetic flowmeter needs to measure fluids of different diameters, such as switching from a DN15 to a DN100 measuring tube 1, the identification unit will intervene first. Assume that a pre-programmed RFID tag is installed on both the DN15 and DN100 measuring tube 1. When the DN15 measuring tube 1 is connected to the system, the RFID reader in the identification unit will automatically scan and read the tag on the DN15 measuring tube 1 to obtain the "DN15" diameter information. The identification unit sends the "DN15" information to the signal processing unit via the internal SPI bus. After receiving "DN15", the signal processing unit will determine the excitation current parameters matching the DN15 diameter, for example, setting the excitation current to a low 0.5A with a 10Hz square wave waveform. Subsequently, the excitation power supply outputs the corresponding excitation current according to the instructions of the signal processing unit. When the measuring tube 1 is DN100, the RFID reader in the identification unit will automatically scan and read the tag on the DN100 measuring tube 1 to obtain the "DN100" diameter information. The identification unit transmits the "DN100" information to the signal processing unit via the SPI bus. After receiving "DN100", the signal processing unit adjusts the excitation current parameters, for example, increasing the excitation current to 1.5A while maintaining the waveform as a 10Hz square wave, to ensure that the magnetic field can effectively cover a larger cross-section.

[0071] In this embodiment, the identification unit can identify the mechanical structure or electronic tag on the measuring tube 1, avoiding the tediousness and potential errors of manual configuration and improving the convenience and reliability of system operation. Clear transmission of aperture information between the identification unit and the signal processing unit ensures that the excitation power supply can dynamically adjust the magnitude and waveform of the excitation current according to the actual aperture, thereby guaranteeing optimal coverage and uniformity of the magnetic field under different aperture measuring tubes 1, effectively solving the problem of decreased measurement accuracy caused by aperture changes. This collaborative control method not only optimizes the adaptability of the universal excitation system 2 but also improves the accuracy of flow calculation, making the entire universal excitation system 2 more versatile and stable in multi-aperture application scenarios.

[0072] Furthermore, the signal processing unit calculates the flow rate of measuring tube 1 by controlling the excitation power supply output to match the magnitude and waveform of the excitation current with the diameter of measuring tube 1, including the following steps: The signal processing unit determines the mapping calibration parameters of the received aperture information based on the pre-stored calibration parameters and the received aperture information. The signal processing unit controls the magnitude and waveform of the excitation current output to match the diameter of the measuring tube 1 according to the determined mapping calibration parameters; The signal processing unit receives the electromotive force information output by the electrode, processes it, and obtains the effective electromotive force. The signal processing unit calculates the flow rate based on the mapping calibration parameters and the effective electromotive force.

[0073] Specifically, the signal processing unit determines the mapping calibration parameters for the received diameter information based on pre-stored calibration parameters and the received diameter information. The calibration parameters are a set of values ​​obtained beforehand through experiments or simulations to correct or optimize the flowmeter measurement results. The mapping calibration parameters refer to a set of specific parameters selected or calculated from the pre-stored calibration parameters for a specific diameter. The signal processing unit can internally store a lookup table that associates different diameter information with corresponding calibration parameters. When specific diameter information is received, the signal processing unit directly retrieves the corresponding mapping calibration parameters from the lookup table. Alternatively, the signal processing unit can store a mathematical model or function for a set of calibration parameters. This model or function takes the diameter information as input and calculates the mapping calibration parameters for that diameter. For example, polynomial fitting or interpolation algorithms can be used to generate these parameters.

[0074] For example, calibration parameters include the magnetic field strength compensation coefficient and the velocity-potential conversion coefficient. The magnetic field strength compensation coefficient is used to correct the deviation between the actual magnetic field strength and the ideal magnetic field strength generated by the excitation coil 21 under different diameters, ensuring that the magnetic field strength reaches the expected value within the measurement area. The velocity-potential conversion coefficient reflects the conversion relationship between fluid velocity and induced electromotive force under specific magnetic field strength and measuring tube 1 geometry conditions. This coefficient is affected by various factors such as the inner wall material of the measuring tube 1, fluid conductivity, and uniformity of magnetic field distribution. These coefficients are usually obtained through actual flow calibration experiments on measuring tubes 1 of different diameters.

[0075] Specifically, the electrode spacing, pipe wall magnetic field loss, and fluid flow field distribution of different diameter measuring tubes 1 have inherent differences. Under the same magnetic field strength, the potential output gain of measuring tubes 1 with different diameters is different. Therefore, each diameter must be matched with a velocity-potential conversion coefficient to ensure a linear correspondence between velocity and potential.

[0076] When the same current is applied to the excitation coil 21, the larger diameter measuring tube 1 has a longer magnetic circuit and greater magnetic field diffusion loss, resulting in a lower effective working magnetic field strength; the smaller diameter measuring tube 1 has a more concentrated magnetic circuit and less loss, resulting in a higher magnetic field strength. The excitation current output is corrected by a magnetic field strength compensation coefficient to offset the difference in magnetic field attenuation caused by the diameter, ensuring that the effective working magnetic field strength of the measuring tube 1 is consistent under different diameters.

[0077] In this embodiment, the signal processing unit can apply the determined mapping calibration parameters to a preset excitation current calculation formula to correct the magnitude of the excitation current, for example, by multiplying the base current value by a compensation coefficient. Alternatively, the mapping calibration parameters can directly include the magnitude and waveform parameters of the excitation current required for a specific aperture and specific magnetic field strength, and the signal processing unit can directly call these parameters to control the excitation power supply.

[0078] As a specific implementation, under the reference aperture, the reference excitation current I0 generates the reference effective magnetic field strength. ,satisfy: f is the current-magnetic field conversion function of the excitation coil, which is determined by the number of coil turns and the core parameters. For any diameter D, the effective magnetic field strength will shift under the same current due to magnetic circuit losses. Therefore, a magnetic field compensation coefficient α is introduced to correct the current output and ensure that: Therefore, it can be deduced that: ,in As the reference excitation current, The magnetic field strength compensation coefficient of the measuring tube under test is given. The compensation coefficient is the reference caliber.

[0079] In this embodiment, the signal processing unit receives the electromotive force (EMF) information output from the electrodes and processes it to obtain an effective EMF. This step aims to extract an EMF signal that accurately reflects the fluid velocity from the original electrode signal, eliminating noise and interference. The signal processing unit can filter the received EMF information, for example, using a low-pass or band-pass filter to remove high-frequency noise and power frequency interference. Alternatively, the signal processing unit can sample, amplify, and perform analog-to-digital conversion on the EMF information, and perform digital signal processing, such as averaging, integration, or synchronous demodulation, to improve the signal-to-noise ratio and obtain a stable effective EMF.

[0080] In this embodiment, the signal processing unit calculates the flow rate based on the mapping calibration parameters and the effective electromotive force (EMF). The signal processing unit can use the flow rate calculation formula q = π × D × E / (4 × k × B), where D is the diameter of the measuring tube, E is the effective EMF, B is the magnetic field strength, and k is the velocity-potential conversion coefficient. By storing the above calculation model internally, the model directly takes the effective EMF and the velocity-potential conversion coefficient as input and outputs the calculated flow rate value of measuring tube 1.

[0081] In one specific implementation, the signal processing unit can be implemented using a high-performance digital signal processor or microcontroller. The non-volatile memory of the signal processing unit pre-stores calibration parameters for different diameters (e.g., DN15, DN50, DN80, DN100). These parameters are organized in the form of a lookup table, with each row corresponding to a diameter, including the magnetic field strength compensation coefficient and flow velocity-potential conversion coefficient for that diameter. For example, when the identification unit detects that the diameter of the currently connected measuring tube 1 is DN50, it transmits this diameter information to the signal processing unit. After receiving the DN50 diameter information, the signal processing unit retrieves the corresponding magnetic field strength compensation coefficient and flow velocity-potential conversion coefficient from the stored lookup table as mapping calibration parameters. Subsequently, the signal processing unit determines the magnitude of the excitation current output by the excitation power supply based on the magnetic field strength compensation coefficient for DN50 and selects a preset dual-frequency waveform optimized for the DN50 diameter for excitation. Simultaneously, the signal processing unit continuously receives the raw electromotive force (EMF) signal from the electrodes and performs digital filtering, such as using a moving average filter combined with a notch filter to remove power frequency interference, and synchronous demodulation processing, to extract a stable and accurate effective EMF. Finally, the signal processing unit uses the velocity-potential conversion coefficient of the DN50 and the obtained effective EMF to accurately calculate the current fluid flow rate based on a pre-stored calculation model.

[0082] This application effectively solves the problem of difficulty in guaranteeing flow measurement accuracy in multi-diameter measurement scenarios due to the differences in physical characteristics of measuring pipes 1 with different diameters. By introducing diameter-specific calibration parameters into excitation control and flow calculation, the system can accurately compensate and calibrate the magnetic field strength and flow velocity-potential conversion relationship, thereby significantly improving the measurement accuracy and stability of the electromagnetic flowmeter under different diameters, ensuring reliable flow data can be provided across a wide diameter range.

[0083] The above description is merely a preferred embodiment of this application and is not intended to limit this application in any way. Although this application has disclosed the preferred embodiment as above, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-mentioned technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. The implementation schemes in the above embodiments can also be further combined or replaced. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this application without departing from the content of the technical solution of this application shall still fall within the scope of this application.

Claims

1. A universal excitation system for electromagnetic flow meters suitable for multi-diameter measurement, characterized in that: include Excitation coil (21) is used to generate a magnetic field perpendicular to the central axis of the measuring tube (1) when energized; The magnetic field is capable of covering the cross-section of the measuring tube (1) of the target diameter; The pole shoe (22) is located between the outer wall of the excitation coil (21) and the measuring tube (1) and is used for magnetic conduction, magnetic focusing and field uniformity. The magnetic yoke (23) is wrapped around the outside of the excitation coil (21) and together with the excitation coil (21) and the pole shoe (22) form a closed magnetic circuit; The excitation power supply is electrically connected to the excitation coil (21) and is used to dynamically adjust the magnitude and waveform of the output excitation current according to the diameter of the measuring tube (1). The processing module controls the magnitude and waveform of the excitation current output by the excitation power supply according to the diameter of the measuring tube (1), and calculates the flow rate of the measuring tube (1).

2. The universal excitation system for electromagnetic flowmeters suitable for multi-diameter measurement according to claim 1, characterized in that: The excitation coil (21) is elliptical; The excitation coil (21) generates a uniform magnetic field in the central region; The magnetic field generated by the excitation coil (21) is concentrated in the central region of the excitation coil (21).

3. The universal excitation system for electromagnetic flowmeters suitable for multi-diameter measurement according to claim 1 or 2, characterized in that: The excitation coil (21) covers a diameter range of DN15 to DN100; The excitation coil (21) is wound uniformly; The number of turns of the excitation coil (21) is optimized to form a magnetic field distribution curve with a wide platform, which is used to expand the uniform magnetic field region.

4. The universal excitation system for electromagnetic flowmeters suitable for multi-diameter measurement according to claim 1 or 2, characterized in that: The coil frame of the excitation coil (21) is made of engineering plastic or composite material through one-time injection molding.

5. The universal excitation system for electromagnetic flowmeters suitable for multi-diameter measurement according to claim 1, characterized in that: The processing module includes an identification unit and a signal processing unit; The identification unit is used to obtain the diameter of the measuring tube (1) and transmit the obtained diameter to the signal processing unit; The signal processing unit controls the magnitude and waveform of the excitation current output by the excitation power supply based on the aperture information transmitted by the identification unit, and calculates the flow rate of the measuring tube (1) through the electromotive force obtained from the electrodes.

6. The universal excitation system for electromagnetic flowmeters suitable for multi-diameter measurement according to claim 5, characterized in that: The measuring tube (1) is provided with a mechanical structure; Different diameter measuring tubes (1) correspond to different mechanical structures; The identification unit obtains the diameter of the measuring tube (1) by identifying different mechanical structures.

7. The universal excitation system for electromagnetic flowmeters suitable for multi-diameter measurement according to claim 5, characterized in that: An electronic tag is installed on the measuring tube (1) to store the diameter information of the measuring tube (1); The identification unit obtains the diameter of the measuring tube (1) by reading the diameter information stored in the electronic tag.

8. A method of controlling a universal excitation system for electromagnetic flowmeters suitable for multi-diameter measurement according to any one of claims 1-7, characterized in that: Includes the following steps: The processing module obtains the diameter information of the measuring tube (1); The processing module controls the excitation power supply output to match the magnitude and waveform of the excitation current with the diameter of the measuring tube (1) based on the obtained diameter information of the measuring tube (1); The processing module calculates the flow rate of the measuring tube (1).

9. The control method for the universal excitation system of electromagnetic flowmeters applicable to multi-diameter measurement according to claim 8, characterized in that: The processing module includes an identification unit and a signal processing unit; The identification unit identifies the mechanical structure or electronic tag on the measuring tube (1) to obtain or read the diameter information of the measuring tube (1); The identification unit transmits the obtained or read diameter information of the measuring tube (1) to the signal processing unit; The signal processing unit receives the aperture information of the measuring tube (1) and controls the excitation power supply to output an excitation current with a magnitude and waveform that matches the aperture of the measuring tube (1). The signal processing unit calculates the flow rate of the measuring tube (1).

10. The control method for the universal excitation system of electromagnetic flowmeters applicable to multi-diameter measurement according to claim 9, characterized in that: The signal processing unit calculates the flow rate of the measuring tube (1) by the following steps: The signal processing unit determines the mapping calibration parameters of the received aperture information based on the pre-stored calibration parameters and the received aperture information. The signal processing unit controls the magnitude and waveform of the excitation current output to match the diameter of the measuring tube (1) according to the determined mapping calibration parameters; The signal processing unit receives the electromotive force information output by the electrode, processes it, and obtains the effective electromotive force. The signal processing unit calculates the flow rate based on the mapping calibration parameters and the effective electromotive force; The calibration parameters include the magnetic field strength compensation coefficient and the velocity-potential conversion coefficient.

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