Switching system and method for improving TMR measurement precision and expanding wide load characteristic

Abstract

The invention belongs to the field of electromagnetic measurement, and provides a switching system and method for improving the TMR measurement precision and expanding the wide load characteristic. The switching system for improving the TMR measurement precision and expanding the wide load characteristic comprises a TMR detection module which comprises a plurality of TMR sensors and is used for sensing the magnetic field change of a current to be detected and converting the sensed magnetic flux into an electric signal; the amplification acquisition unit is used for amplifying the electric signal output by the TMR detection module; the algorithm unit is used for judging the current working state of the first TMR sensor based on the digital signal output by the amplification acquisition unit, and feeding back an instruction to the control unit when the first TMR sensor works in a non-excellent working section; and the control unit is used for receiving a feedback instruction of the algorithm unit and switching the second TMR sensor to work according to the feedback instruction, so that the TMR sensor in the excellent working section works. And the requirements of different magnetic field intensities in wide-range measurement are met.

Description

Technical Field

[0001] The present invention belongs to the technical field related to electromagnetic measurement, and particularly relates to a switching system and method for improving the measurement accuracy of TMR and expanding the wide-load characteristics. Background Art

[0002] The statements in this part only provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] Accurate current measurement and wide-range measurement performance have become core elements at present. Taking the power system as an example, in the whole process from the energy conversion in the power station, to the power transmission line and then to the voltage transformation in the substation, and finally to the power consumption terminals of thousands of households and various industrial facilities, accurately controlling the current value plays a crucial role in calculating the power transmission efficiency, troubleshooting faults, and optimizing power distribution. Deviation of current data in any link may lead to a reduction in power transmission efficiency, or even cause large-scale power outages, affecting the normal operation of social production and people's lives. In the electric vehicle industry, the battery management system must accurately monitor the charging and discharging current of the battery to ensure the battery life cycle and vehicle driving safety. When the vehicle is in different operating states such as starting, accelerating, cruising, decelerating, and charging, the current change range is extremely wide, from a tiny standby current to an instantaneous discharge current of hundreds of amperes. If these current changes cannot be accurately measured, the battery may be shortened in service life due to overcharging and over-discharging, or even pose safety hazards, threatening the lives of passengers and drivers.

[0004] Traditional current measurement methods, such as the shunt measurement method, although simple in structure, have obvious disadvantages. When measuring large currents, it generates a large amount of heat, which not only causes energy loss but also may affect the measurement accuracy due to temperature rise; its low accuracy makes it difficult to meet the requirements in industrial scenarios with extremely high data accuracy requirements; and due to its own principle limitations, it is difficult to meet the wide-range measurement requirements. It has insufficient resolution when measuring small currents and is limited in range when measuring large currents. Although the Hall effect current sensor makes up for some of the shortcomings of the shunt to a certain extent, in terms of measurement precision, it is still unable to cope with high-precision industrial applications; in terms of temperature constancy, it is greatly affected by the ambient temperature, resulting in measurement data drift; in terms of miniaturization of volume, it is also difficult to meet the increasingly stringent space requirements for electronic devices pursuing a compact design.

[0005] Although there are currently some improved technologies for TMR sensors, they all have limitations. Some technologies are dedicated to optimizing the performance of TMR elements to enhance the overall efficiency of the array, but they cannot fundamentally solve the problems caused by the fixed distance. In existing research, the technical solutions for distance adjustment of TMR arrays are mostly insufficient. Some solutions can only perform simple distance fine-tuning, making it difficult to meet the requirements of high-precision and large-range distance adjustment. In actual industrial production, different measurement objects and different installation environments pose diverse requirements for the distance adjustment of TMR arrays. In the smart grid, in the face of power equipment with different voltage levels and capacities, TMR arrays are also required to have the ability of high-precision and large-range distance adjustment to ensure the accurate acquisition of various current data.

[0006] Judging from the existing research results, there are indeed many deficiencies in the technical solutions for distance adjustment of TMR arrays. Some existing distance adjustment solutions can only achieve simple distance fine-tuning. In actual operation, such solutions usually rely on relatively basic mechanical structures, such as simple screw adjustment devices, to slightly change the distance between the TMR array and the object to be measured by rotating the screw. However, this method is unable to meet the requirements when facing high-precision and large-range distance adjustment. On the one hand, due to the accuracy limitations of the mechanical structure itself, it is difficult to achieve distance adjustment with sub-millimeter or even higher precision. On the other hand, its adjustment range is extremely limited and cannot meet the requirements for large-distance range adjustment in scenarios such as the detection of large industrial equipment and measurement in complex space environments. Summary of the Invention

[0007] To overcome the above deficiencies of the existing technology, the present invention provides a switching system and method for improving TMR measurement accuracy and expanding wide-load characteristics. The switching system can flexibly adjust the distance from the magnetic field source according to different measurement scenarios, avoiding the situation where the sensor cannot be in the optimal measurement position when the magnetic field strength changes, which affects the measurement accuracy and linearity.

[0008] To achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a switching system for improving TMR measurement accuracy and expanding wide-load characteristics, including: a TMR detection module, an amplification and acquisition unit, an algorithm unit, and a control unit; The TMR detection module includes multiple TMR sensors, which are used to sense the magnetic field change of the current to be measured and convert the sensed magnetic flux into an electrical signal; The amplification and acquisition unit is used to amplify the electrical signal output by the TMR detection module and convert the amplified electrical signal into a digital signal; The algorithm unit is used to judge the current working state of the first TMR sensor based on the digital signal output by the amplification and acquisition unit. When the first TMR sensor works in a non-optimal working section, a feedback instruction is sent to the control unit; The control unit is used to receive the feedback instruction from the algorithm unit and switch the second TMR sensor to work according to the feedback instruction, so that the TMR sensor in the optimal working section works, where the distances of the first TMR sensor and the second TMR sensor from the magnetic field source are different.

[0009] Further, the TMR detection module further includes a temperature sensor, and the temperature sensor is used to detect the working temperature of the TMR sensor.

[0010] Further, the multiple TMR sensors are connected in series at equal intervals in a linear or planar direction to form a one-dimensional or two-dimensional array. The positions of each TMR sensor from the magnetic field source are different, and the TMR sensor is used to detect the magnetic field change at the position where it is located.

[0011] Further, the algorithm unit is used to perform temperature compensation according to the working temperature of the TMR sensor collected by the TMR detection module to ensure that the TMR sensor can maintain a stable and accurate measurement working state in different temperature environments.

[0012] Further, the algorithm unit realizes the temperature compensation of the TMR sensor by correcting the zero offset and correcting the sensitivity attenuation.

[0013] Further, the algorithm unit is used to perform optimal working section selection control according to the signal output by the amplification and acquisition unit, analyze the characteristics of the digital signal according to a preset threshold, and judge the current working state of the TMR sensor.

[0014] Further, the amplification and acquisition unit includes a plurality of amplification and acquisition modules. Each amplification and acquisition module is connected to a TMR sensor. Each amplification and acquisition module includes a differential amplification circuit, an ADC sampling circuit, and an amplifier. The differential amplification circuit is used to amplify the signal; the ADC sampling circuit is used to perform analog-to-digital conversion on the amplified signal, and the amplifier is used to further amplify the digital signal after analog-to-digital conversion.

[0015] Further, in the TMR sensor, the calculation formula for the change of magnetic field intensity with distance is:

[0016] where B is the magnetic field intensity, μ 0 is the vacuum permeability, I is the current, Ris the distance between the TMR sensor and the magnetic field source.

[0017] Further, the control unit is configured to receive the feedback instruction from the algorithm unit and select the TMR sensor operating in the excellent working section according to the feedback instruction.

[0018] Further, the multiple TMR sensors are respectively arranged at different positions from the magnetic field source. When the distance between the first TMR sensor and the magnetic field source is less than the distance between the second TMR sensor and the magnetic field source, the algorithm unit is configured to judge the current working state of the first TMR sensor based on the digital signal output by the amplification and acquisition unit. When the first TMR sensor operates in a non-excellent working section, a feedback instruction is sent to the control unit; The control unit is configured to receive the feedback instruction from the algorithm unit and switch the second TMR sensor to work according to the feedback instruction. The algorithm unit is configured to judge the current working state of the second TMR sensor based on the digital signal output by the amplification and acquisition unit. When the second TMR sensor operates in the excellent working section, the control unit controls the switch of the second TMR sensor to work and sends a signal to the inverter output unit.

[0019] Further, it further includes an inverter output unit, and the inverter output unit receives the signal from the control unit to convert direct current into alternating current and amplify it to the required output voltage to achieve the final output.

[0020] Further, the inverter output unit uploads the measurement result and the working state information to the host computer in real time through a wireless transmission module.

[0021] In a second aspect, the present invention provides a switching method for improving the TMR measurement accuracy and expanding the wide-load characteristic, adopting a switching system for improving the TMR measurement accuracy and expanding the wide-load characteristic as described above. The method includes: Utilize the first TMR sensor to sense the magnetic field change of the current to be measured and convert the sensed magnetic flux into an electrical signal; Amplify the electrical signal and convert the amplified electrical signal into a digital signal; Judge the current working state of the first TMR sensor according to the output digital signal. When the first TMR sensor operates in a non-excellent working section, switch to the second TMR sensor to sense the magnetic field change of the current to be measured, so that the TMR sensor in the excellent working section works, wherein the distances between the first TMR sensor and the second TMR sensor and the magnetic field source are different.

[0022] Further, the distance between the first TMR sensor and the magnetic field source is less than the distance between the second TMR sensor and the magnetic field source.

[0023] The above one or more technical solutions have the following beneficial effects: The system of the present invention can flexibly adjust the distance from the magnetic field source according to different measurement scenarios, avoiding the situation that the sensor cannot be in the best measurement position when the magnetic field strength changes, which affects the measurement accuracy and linearity, and solving the problems of weak magnetic field induction intensity and easy signal interference at low current, and easy magnetic saturation at high current.

[0024] The effective adjustment of the distance between the magnetic field source and the TMR sensor in the present invention can not only perform fine adjustment with a small amplitude to capture the subtle changes of the magnetic field and meet the high-precision measurement requirements, but also achieve a large-scale distance adjustment to adapt to the requirements of different magnetic field strengths in a wide range of measurements. This enables the present invention to maintain good measurement performance in a wide range of load current scenarios from low current to high current, greatly expanding the application range of the TMR sensor.

[0025] The temperature sensor in the TMR detection module of the present invention monitors the temperature in real time, and the algorithm unit performs temperature compensation. In different working temperature environments, it can dynamically adjust the measurement parameters, effectively eliminate the influence of temperature on the performance of the TMR sensor, ensure that the measurement accuracy remains stable in a wide temperature range, and further enhance the overall measurement accuracy.

[0026] Advantages of additional aspects of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The specification drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0028] Figure 1 It is a structural diagram of a switching system for improving TMR measurement accuracy and expanding wide-load characteristics in an embodiment of the present invention; Figure 2 It is an application schematic diagram of a switching system for improving TMR measurement accuracy and expanding wide-load characteristics in an embodiment of the present invention; Figure 3 It is a multi-gear voltage linearity judgment and amplification flowchart in an embodiment of the present invention; Figure 4 It is a circuit diagram of the TMR sensor in an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention.

[0031] In the case of no conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0032] Term Explanation: TMR (Tunnel Magneto Resistance Sensor): That is, a tunnel magnetoresistance sensor, a magnetic sensitive element based on the tunnel magnetoresistance effect, mainly used to detect the magnitude, direction or change of a magnetic field, etc.

[0033] As described in the background art, with the continuous advancement of electronic technology towards high precision, miniaturization and low energy consumption, TMR sensors have begun to receive wide attention due to their high sensitivity, low energy consumption, fast response and relatively good temperature stability. However, TMR sensors also encounter many difficulties in actual applications. Their measurement accuracy is easily affected by factors such as external magnetic field interference, self-temperature fluctuations and manufacturing process differences. In a complex electromagnetic environment, such as near a substation or a large motor, the stray magnetic field will be superimposed on the measured magnetic field, resulting in deviations in the measurement data of the TMR sensor and seriously affecting the operation reliability of the equipment; and during the wide-range current measurement process, whether the current is too large or too small, the output characteristics of the TMR sensor will change, and it is difficult to maintain a high-precision measurement level throughout the entire range. In the case of low current conditions, the signal is weak and easily interfered by noise, making the measurement results full of uncertainty; in the case of high current, the TMR sensor may fall into a magnetic saturation state, losing the measurement linear characteristics and resulting in distorted measurement data. Due to the fixed distance of the TMR array and the defects in related improvement technologies, there are frequent problems when dealing with multiple application scenarios and complex measurement requirements. There is an urgent need for a method to improve the TMR measurement accuracy and expand the wide-load characteristics to enhance its performance and adaptability.

[0034] Figure 1 This is a structural diagram of a switching system for improving the TMR measurement accuracy and expanding the wide-load characteristics in the embodiments of the present invention; see Figure 1 The switching system includes a TMR detection module, an amplification and acquisition unit, a control unit, an algorithm unit and an inverter output unit. The TMR detection module, the amplification and acquisition unit, the control unit, the algorithm unit and the inverter output unit are all connected to the upper computer through a wireless transmission module, and the upper computer is connected to a database.

[0035] Among them, the TMR detection module includes a plurality of TMR sensors, which are used to sense the magnetic field change of the current to be measured and convert the sensed magnetic flux into an electrical signal; The amplification acquisition unit is used to amplify the electrical signal output by the TMR detection module and convert the amplified electrical signal into a digital signal; The algorithm unit is used to judge the current working state of the first TMR sensor based on the digital signal output by the amplification acquisition unit. When the first TMR sensor works in a non-excellent working section, a feedback instruction is sent to the control unit; The control unit is used to receive the feedback instruction from the algorithm unit and switch the second TMR sensor to work according to the feedback instruction, so that the TMR sensor in the excellent working section works. Among them, the distances of the first TMR sensor and the second TMR sensor from the magnetic field source are different; The inverter output unit is used to receive the signal from the control unit, convert direct current into alternating current, and amplify it to the required output voltage to achieve the final output. And the inverter output unit uploads the measurement results and working state information to the host computer in real time through a wireless transmission module.

[0036] In some embodiments, the TMR detection module further includes a temperature sensor, and the temperature sensor is used to detect the working temperature of the TMR sensor.

[0037] In some embodiments, the multiple TMR sensors are connected in series at equal intervals in a linear or planar direction to form a one-dimensional or two-dimensional array. The positions of each TMR sensor from the magnetic field source are different, and the TMR sensor is used to detect the magnetic field change at the position where it is located.

[0038] In some embodiments, the algorithm unit is used to perform temperature compensation according to the working temperature of the TMR sensor collected by the TMR detection module to ensure that the TMR sensor can maintain a stable and accurate measurement working state in different temperature environments.

[0039] In some embodiments, the algorithm unit realizes the temperature compensation of the TMR sensor by correcting the zero offset and correcting the sensitivity attenuation.

[0040] In some embodiments, the algorithm unit is used to perform excellent working section selection control according to the signal output by the amplification acquisition unit, analyze the characteristics of the digital signal according to a preset threshold, and judge the current working state of the current TMR sensor.

[0041] In some embodiments, the amplification acquisition unit includes a plurality of amplification acquisition modules. Each amplification acquisition module is connected to a TMR sensor. Each amplification acquisition module includes a differential amplification circuit, an ADC sampling circuit, and an amplifier. The differential amplification circuit is used to amplify the signal; the ADC sampling circuit is used to perform analog-to-digital conversion on the amplified signal, and the amplifier is used to further amplify the digital signal after analog-to-digital conversion.

[0042] In some embodiments, in the TMR sensor, the calculation formula for the change of magnetic field intensity with distance is as follows:

[0043] where, B is the magnetic field intensity, μ 0 is the magnetic permeability of vacuum, I is the current, R is the distance between the TMR sensor and the magnetic field source.

[0044] In some embodiments, the control unit is configured to receive the feedback instruction from the algorithm unit and select the TMR sensor operating in the excellent working section according to the feedback instruction.

[0045] In some embodiments, the multiple TMR sensors are respectively arranged at different positions from the magnetic field source. When the distance between the first TMR sensor and the magnetic field source is less than the distance between the second TMR sensor and the magnetic field source, the algorithm unit is configured to judge the current working state of the first TMR sensor based on the digital signal output by the amplification and acquisition unit. When the first TMR sensor operates in a non-excellent working section, a feedback instruction is sent to the control unit; The control unit is configured to receive the feedback instruction from the algorithm unit and switch the second TMR sensor to work according to the feedback instruction. The algorithm unit is configured to judge the current working state of the second TMR sensor based on the digital signal output by the amplification and acquisition unit. When the second TMR sensor operates in the excellent working section, the control unit controls the second TMR sensor to switch to work and sends a signal to the inverter output unit.

[0046] The solution of this embodiment enables the TMR detection module to flexibly adjust and switch the distance from the magnetic field source according to different measurement scenarios, avoiding the situation that the TMR sensor cannot be in the best measurement position when the magnetic field intensity changes, which affects the measurement accuracy and linearity, and solving the problems of weak magnetic induction intensity and easy signal interference at low current and easy magnetic saturation at high current; breaking through the limitation of the existing improvement technologies that only optimize the performance of the TMR element itself, fully considering the complexity of the magnetic field distribution in the whole measurement system and the comprehensive effect of the distance factor on the measurement result, ensuring that high-precision measurement can be stably achieved in complex practical application environments with multiple magnetic field interference sources, large temperature changes or wide-range current fluctuations; this embodiment improves the distance adjustment scheme between the TMR sensor and the magnetic field source, enabling it to achieve a large range and precise distance adjustment, meeting the requirements of high-precision measurement for accurately capturing subtle changes in the magnetic field and the distance adjustment requirements for different magnetic field intensities in wide-range measurement, and thus promoting the effective application and popularization of the TMR sensor in complex wide-load measurement scenarios.

[0047] The magnetic field change of related devices is sensed by the TMR detection module. Combining with the TMR sensors inside the TMR detection module, key magnetic parameters that can characterize the operating state of the devices are obtained. These magnetic parameters are closely related to electrical parameters such as the current and impedance of the devices, so as to indirectly obtain relevant parameter information that can be used to evaluate the operating energy efficiency of the devices. Secondly, the magnetic parameters collected by the TMR detection module are transmitted to the amplification and acquisition unit. The differential amplification unit in the amplification and acquisition unit amplifies the weak magnetic signals, and then the ADC acquisition unit converts them into digital signals and transmits them to the algorithm unit. The algorithm unit uses corresponding algorithms to analyze and calculate these data. During the calculation process, by selecting the excellent working section of the TMR sensor, performing temperature compensation and executing bus algorithms and other operations, accurate data of the device operation are obtained, and then the device operation energy efficiency data are obtained and can be output. Finally, the relevant data can be wirelessly uploaded to the data management system supporting this device through the wireless transmission module, and finally the detection results are clearly displayed on the graphical interface of the system, providing a reliable basis for the staff to understand the performance state of the device timely, comprehensively and accurately, so that they can maintain and optimize the device according to these data. At the same time, it also provides guarantee for the safe and efficient operation of the device under different load conditions, effectively expanding the application range of this device in the wide-load characteristic aspect and significantly improving the TMR measurement accuracy.

[0048] Figure 2 It is an application schematic diagram of the switching system for improving TMR measurement accuracy and expanding wide-load characteristics in the embodiment of the present invention; referring to Figure 2 , the current wire passes through the TMR detection module. The TMR detection module is centered on the current wire and is provided with four annular TMR sensors. Each TMR sensor is connected to an amplification and acquisition module. Each amplification and acquisition module includes a differential amplification unit, an ADC acquisition unit and an amplifier connected in series in turn. The TMR detection module is responsible for sensing the current signal of the related device, outputting a magnetic field signal, and converting the magnetic field signal into a voltage signal for output. The voltage signal is amplified by the amplification and acquisition module and then enters the embedded chip, and is processed by the algorithm unit to screen out the working section most suitable for the current measurement requirement; the switching current gear is controlled by the control unit to realize the access of the corresponding TMR sensor. At the same time, the inverter output unit receives the signal of the control unit, performs analog-to-digital conversion (DAC), and amplifies it to the required output voltage to realize the final output.

[0049] The TMR detection module is responsible for sensing the current signals of relevant devices and converting them into electrical signals for output. The amplification and acquisition unit is a key link in the entire signal processing chain. When connecting the TMR detection module and the amplification and acquisition unit, it is necessary to ensure the stability and accuracy of signal transmission. A transmission line with low noise and strong anti-interference ability should be used to reduce signal loss and distortion during transmission. After the signal is transmitted to the amplification and acquisition unit, it first enters the differential amplification unit. The differential amplification circuit can effectively suppress common-mode interference and improve the signal-to-noise ratio of the signal. For the weak signal output by the TMR sensor, after being amplified by the differential amplification unit, the signal amplitude can be increased to a level suitable for subsequent processing. The algorithm unit is connected to the control unit. The algorithm unit transmits the processing results to the control unit. The control unit selects the TMR sensor based on this. The connection between the algorithm unit and the control unit is a key link to achieve the automatic control of the system. After the algorithm unit completes the processing and analysis of the digital signal, it transmits the processing results and instructions to the control unit. These instructions contain information on adjusting the working state of the system, coping strategies for different measurement conditions, etc. After receiving the signal from the algorithm module, the control unit makes decisions based on this information. The connection between the control unit and the inverter output unit constructs a complete link from measurement to output control. The control unit sends signals to the inverter output unit according to the instructions and processing results provided by the algorithm unit. These signals contain control requirements for the output current and voltage, as well as the operating state information of the system, etc. After receiving the signal from the control unit, the inverter output unit converts the DC signal into an AC signal and amplifies the voltage to achieve the output. After the inverter output unit completes the output function, it transmits relevant data such as measurement results and working state information to the upper computer in real time via the wireless transmission module for remote monitoring, data analysis, and further issuing of control instructions, etc.

[0050] The digital signal is input into the algorithm unit. The algorithm unit performs the selection control of the excellent working section based on the signal, compensates with temperature data, and executes the bus algorithm to process the data. The digital signal after being converted by the ADC acquisition unit is input into the algorithm unit for in-depth processing. The algorithm unit performs the selection control of the excellent working section based on the input signal. According to the preset algorithm and threshold, it analyzes the characteristics of the digital signal, judges the working state of the current TMR sensor, and thus selects the most suitable working section for the current measurement requirement. Compensating with temperature data is another important function of the algorithm module. Since temperature has a significant impact on the performance of the TMR sensor, the algorithm unit will call the temperature data previously collected and transmitted by the temperature sensor and correct the measurement data according to the pre-established temperature compensation model.

[0051] In one or more embodiments, the TMR detection module includes a plurality of TMR sensors to select excellent characteristics with good induction curve characteristics and high stability. Among them, the plurality of TMR sensors are connected in series at equal intervals along a linear or planar direction to form a one-dimensional or two-dimensional array. Each TMR sensor detects the magnetic field component at its location, and the series output signals of the TMR sensors can be spliced into a magnetic field distribution curve. For example, a one-dimensional array detects the attenuation of the magnetic field intensity around a conductor with distance.

[0052] When multiple TMR sensors are working, each TMR sensor can produce a unique response to the measured current. Due to the fact that in the manufacturing process of different TMR sensors, even if the same process is adopted, there will be slight performance differences, which are reflected in multiple key performance indicators such as sensitivity, noise level, and linearity. Through the subsequent series-connected working circuit, these differences can be utilized to comprehensively analyze and screen the output signals of a large number of TMR sensors.

[0053] The distance of each TMR sensor from the current to be measured is different. The calculation formula for the change of magnetic field intensity with distance is:

[0054] where B is the magnetic field intensity, is the vacuum permeability, I is the current, and R is the distance from the magnetic field source to the TMR sensor.

[0055] The performance of the TMR sensor will be significantly affected by temperature fluctuations. Temperature changes may cause problems such as sensitivity drift and output signal deviation of the sensor.

[0056] In this embodiment, the TMR detection module is also provided with a temperature sensor. By detecting the temperature of the working environment of the TMR sensor in real time through the temperature sensor, accurate temperature data can be obtained. These data can be transmitted to the backend data processing system in real time, and using the pre-established temperature compensation model, the measurement data of the TMR sensor can be dynamically corrected, effectively eliminating the adverse effects of temperature changes on the performance of the TMR sensor, ensuring that the TMR sensor can maintain a stable and accurate measurement working state in different temperature environments, and further improving the accuracy and reliability of the measurement of the entire device.

[0057] Specifically, the temperature compensation model is specifically: Before performing temperature compensation, it is necessary to obtain the temperature-sensitive parameters of the TMR sensor through calibration experiments at multiple temperature points as the input of the compensation model. The specific steps are as follows: 1. Experimental environment setup Place the sensor in a constant temperature oven and set at least 3 typical temperature points such as low temperature T1, normal temperature T2, and high temperature T3 to cover the target working temperature range; at each temperature point, ensure that the sensor reaches thermal equilibrium.

[0058] 2. Measurement of the zero-temperature-drift parameter V0(T) When there is no input signal, measure the output voltage Vzero(Ti) of the TMR sensor, record the zero voltage corresponding to each temperature Ti, and determine the zero-temperature-drift coefficient through polynomial fitting.

[0059] 3. Measurement of the sensitivity-temperature-drift parameter S(T) Apply a fixed standard input signal, measure the corresponding output voltage Vsig(Ti), calculate the actual sensitivity at each temperature point, and determine the sensitivity-temperature-drift coefficient through a linear model.

[0060] By performing zero correction on the original voltage, performing sensitivity correction based on the zero-corrected voltage, and introducing the temperature variable into the sensitivity-corrected voltage, temperature compensation for the TMR sensor is achieved.

[0061] Among them, the zero-offset correction is as follows: V temp1 =V y -（ 0.1 ×ΔT) Among them, V y is the original voltage; ΔT is the temperature change; for every 1°C increase in temperature, the zero voltage increases by 0.1 mV.

[0062] The sensitivity attenuation correction is as follows: V corrected =V temp1 ×( 1 + 0.002 ×ΔT) Among them, for every 1°C increase in temperature, the sensitivity decreases by 0.2%, and the signal needs to be amplified for compensation.

[0063] By using a temperature sensor to detect the temperature of the working environment of the TMR sensor in real time, accurate temperature data can be obtained. These data can be transmitted to the backend data processing system in real time, and the measured data of the TMR sensor can be dynamically corrected using a pre-established temperature compensation model.

[0064] In one or more embodiments, the algorithm unit is used to implement the selection and control of the excellent working section, perform temperature compensation, and execute the bus algorithm; determine the corresponding standard voltage output according to the current to be measured, compare the output signal of the TMR sensor with the standard voltage after processing, and switch to the TMR sensor in the excellent working section according to the comparison result.

[0065] The series-connected TMR sensors are respectively arranged at different positions from the magnetic field source, such as including the first TMR sensor, the second TMR sensor, the third TMR sensor... the Nth TMR sensor. The distances of the first TMR sensor, the second TMR sensor, the third TMR sensor... the Nth TMR sensor from the magnetic field source are the first distance, the second distance, the third distance... the Nth distance respectively, where the first distance < the second distance < the third distance <... < the Nth distance. When the TMR detection module starts to detect, first, the magnetic field change of the induced current is sensed by the first TMR sensor, and the sensing result is output and processed by the amplification and acquisition unit, and then enters the algorithm unit. The algorithm unit judges whether it works in the excellent working section according to the result detected by the first TMR sensor. If so, the subsequent process continues; if not, the magnetic field change of the induced current of the second TMR sensor in the TMR detection module is switched through the control unit, and the above process is repeated until the magnetic field change of the induced current of the TMR sensor in the excellent working section in the TMR detection module is achieved.

[0066] When the range of the current to be measured is 0 - 100A, the standard voltage output at 100A is 4V. The algorithm adopts a piecewise function form, that is, the distances of multiple TMR sensors, namely the first TMR sensor to the fourth TMR sensor, from the magnetic field source are d1, d2, d3, and d4 respectively, where d1 < d2 < d3 < d4; First, the signal output by the first TMR sensor is processed by the amplification and acquisition unit and then input to the algorithm unit. The algorithm unit judges whether the voltage detected by the first TMR sensor exceeds 4V. If the voltage detected by the first TMR sensor exceeds 4V, the magnetic field change is sensed by the second TMR sensor. Similarly, the algorithm unit judges whether the voltage detected by the second TMR sensor exceeds 4V. If it does not exceed, the second TMR sensor is the excellent working section. If it exceeds, the magnetic field change is sensed by the third TMR sensor, and so on, to realize the selection of the excellent working section.

[0067] Figure 3 It is the flowchart of multi - gear voltage linear judgment and amplification in the embodiment of the present invention. Refer to Figure 3 ., the system initializes the configuration and sequentially judges whether the voltages of gear one, gear two until gear N are super - linear in ascending order. If not, the voltage of gear one is amplified. If the voltage of gear N is super - linear, the voltage of gear N is amplified. Finally, the amplified voltage signal is output. This logic is used in a multi - range voltage sensor / amplifier system, preferentially selecting the low gear to ensure accuracy, and switching to the high gear when it is super - linear to achieve the dynamic balance of accuracy and range.

[0068] In one or more embodiments, the control unit is responsible for controlling the selection of the TMR sensors. The only difference among the TMR sensors is their distance from the energized conductor. Different TMR sensors with different distances are selected to adjust to the TMR sensors in the excellent working section.

[0069] As an alternative embodiment, multiple TMR sensors are connected in series circuit form, and an electronic switch is connected in parallel at both ends of each TMR sensor. Each TMR sensor is connected to the control end of each electronic switch through an IO pin, and the switch is turned on or off through high and low level signals; different TMR sensors are switched by the control unit, and then the corresponding electronic switch is turned on to realize the operation of the corresponding TMR sensor, effectively adjusting the distance between the magnetic field source and the TMR sensor. It can not only perform fine adjustment with a small amplitude to capture the subtle changes of the magnetic field and meet the high-precision measurement requirements, but also realize a large range of distance adjustment to adapt to the requirements of different magnetic field intensities in wide-range measurement. This enables the present invention to maintain good measurement performance in wide load current scenarios such as low current to high current, greatly expanding the application range of TMR sensors.

[0070] The TMR detection module, amplification and acquisition unit, algorithm unit, control unit, and inverter output unit cooperate closely. Under wide load conditions, each module can automatically adjust the working mode and parameter settings according to different parameters such as current and magnetic field intensity. For example, the algorithm unit dynamically selects the excellent working section of the TMR according to the measurement data, and the control unit switches the appropriate control chip, etc., so as to ensure that the entire device always maintains a stable and efficient working state during the wide load change process and effectively cope with the complex and changeable measurement environment.

[0071] Figure 4 is the circuit diagram of the TMR sensor in the embodiment of the present invention. Refer to Figure 4 , the 1st pin of the TMR2104LS chip is connected to +1V, the 2nd pin is grounded, the 4th pin is connected to the positive input terminal (4th pin) of the amplifier U1, the 5th pin is connected to the negative input terminal (1st pin) of the amplifier U1, one end of the resistor R1 is connected to the 2nd pin of the amplifier U1, and the other end is connected to the 3rd pin of the amplifier U1. The 5th pin of the amplifier U1 is respectively connected to -5V, one end of the capacitor C2, and one end of the capacitor C6. The other ends of the capacitor C2 and the capacitor C6 are grounded; the 6th pin of the amplifier U1 is grounded, the 7th pin of the amplifier U1 is connected to one end of the resistor R4, the other end of the resistor R is respectively connected to V1 and one end of the capacitor C9, and the other end of the capacitor C9 is grounded. The 8th pin of the amplifier U1 is respectively connected to +5V, one end of the capacitor C1, and one end of the capacitor C5. The other ends of the capacitor C1 and the capacitor C5 are grounded. The amplifier U1 can adopt AD8220ARMZ-R7.

[0072] In this embodiment, the TMR sensor uses the TMR2104LS chip, outputs a differential voltage through a full-bridge structure, and inputs it into the AD chip (AD8220) for amplification. After the input differential signal is zero-adjusted and amplified, its DC bias is eliminated, and it is amplified by an appropriate multiple. Then, the data is sent to the acquisition module for reading.

[0073] The algorithm unit and the control unit can use the ARM-Cortex-M4 32-bit single-chip microcomputer of the STM32F427ZGT6 chip. The STM32F427ZGT6 chip includes a power supply circuit, a clock circuit, a reset circuit, a program download circuit, and a startup configuration circuit, and all of these circuits can be implemented using existing circuits. The algorithm unit and the control unit also include: an external high-speed crystal oscillator (8MHz) circuit, a power management circuit (ME6211C33M5G), a debugging interface (SWD mode), a startup interface (BOOT) selection circuit, an RS485 serial communication module, a signal acquisition module, a data transmission module, etc., and all of these circuits and modules can be implemented using existing circuits. The signal acquisition module is electrically connected to the data transmission module and is used for the input of external TMR signals. The data transmission module outputs the processed data to the terminal.

[0074] The data transmission module can use the built-in ADC module of the STM32 to receive the TMR acquisition data signal, convert the data signal into a corresponding series of ADC data, and cache the ADC data in the first array by means of DMA reception; call the ADC data processing function to convert the ADC data into the corresponding data; and cache it in the third array; pre-define a C language structure pointer according to the data packet protocol, and then read out the specific data and content cached in the third array. Calibrate and screen the data of each channel collected by the set standard data, and then upload it to the acquisition terminal through RS485.

[0075] In the solution of this embodiment, multiple TMR sensors in the TMR detection module will respectively detect the magnetic parameter signals of the current to be measured, and then transmit the outputs to their respective corresponding amplification and acquisition units. The amplification and acquisition unit includes a differential amplification unit and an ADC acquisition unit. The differential amplification unit amplifies the output signal of the TMR sensor, and the amplified signal is then subjected to analog-to-digital conversion by the ADC acquisition unit. The converted digital signal is input to the algorithm unit. The algorithm unit realizes the selection and control of the excellent working section according to the received signal, compensates for the temperature based on the temperature data detected by the temperature sensor in the TMR detection module, and executes the bus algorithm to comprehensively process the data. The algorithm unit transmits the processed data and control instructions to the control unit, and the control unit performs the selection operation of the TMR sensor according to this information. The control unit sends relevant control signals to the inverter output unit. After receiving the signals, the inverter output unit converts the direct current into alternating current and amplifies it to the required output voltage to achieve the final output function. The present invention can achieve high-precision measurement in complex application environments such as the presence of multiple magnetic field interference sources, large temperature changes, or wide-range current fluctuations, effectively expanding the wide-load characteristics of the TMR sensor.

[0076] In another embodiment, a method for improving the TMR measurement accuracy and expanding the wide-load characteristics is also provided. The method includes: Using a first TMR sensor to sense the magnetic field change of the current to be measured and convert the sensed magnetic flux into an electrical signal; Amplify the electrical signal and convert the amplified electrical signal into a digital signal; Judge the current working state of the first TMR sensor according to the output digital signal. When the first TMR sensor is working in a non-excellent working section, switch to the second TMR sensor to sense the magnetic field change of the current to be measured, so that the TMR sensor in the excellent working section works, where the distances between the first TMR sensor and the second TMR sensor and the magnetic field source are different.

[0077] In this embodiment, the temperature sensor is used to detect the temperature of the working environment of the TMR sensor in real time, and accurate temperature data can be obtained. These data can be transmitted to the backend data processing system in real time. Using the pre-established temperature compensation model, the measurement data of the TMR sensor is dynamically corrected, effectively eliminating the adverse effects of temperature changes on the performance of the TMR sensor, ensuring that the TMR sensor can maintain a stable and accurate measurement working state in different temperature environments, and further improving the accuracy and reliability of the measurement of the entire device.

[0078] In the context of the present invention, the computer program code or related data can be carried by any suitable carrier so that the device, apparatus or processor can perform the various processes and operations described above. Examples of the carrier include signals, computer-readable media, and the like. Examples of signals can include electrical, optical, radio, sound, or other forms of propagated signals, such as carrier waves, infrared signals, etc.

[0079] Those of ordinary skill in the art can realize that the units and algorithm steps of the examples described in conjunction with this embodiment can be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of this application.

[0080] Although the specific implementation manners of the present invention have been described above in conjunction with the accompanying drawings, it is not a limitation on the protection scope of the present invention. Those skilled in the art should understand that, based on the technical solution of the present invention, various modifications or deformations that can be made by those skilled in the art without creative efforts are still within the protection scope of the present invention.

Claims

1. A switching system for improving the TMR measurement accuracy and expanding the wide-load characteristics, characterized in that, Including: A TMR detection module, an amplification and acquisition unit, an algorithm unit, and a control unit; The TMR detection module includes a plurality of TMR sensors, which are used to sense the magnetic field change of the current to be measured and convert the sensed magnetic flux into an electrical signal; The amplification and acquisition unit is used to amplify the electrical signal output by the TMR detection module and convert the amplified electrical signal into a digital signal; The algorithm unit is used to judge the current working state of the first TMR sensor based on the digital signal output by the amplification and acquisition unit. When the first TMR sensor works in a non-excellent working section, a feedback instruction is sent to the control unit; The control unit is used to receive the feedback instruction from the algorithm unit and switch the second TMR sensor to work according to the feedback instruction, so that the TMR sensor in the excellent working section works, wherein the distances of the first TMR sensor and the second TMR sensor from the magnetic field source are different.

2. The switching system for improving the TMR measurement accuracy and expanding the wide-load characteristics as claimed in claim 1, wherein A plurality of TMR sensors are connected in series at equal intervals in a linear or planar direction to form a one-dimensional or two-dimensional array. The positions of each TMR sensor from the magnetic field source are different, and the TMR sensors are used to detect the magnetic field change at the corresponding positions.

3. The switching system for improving the TMR measurement accuracy and expanding the wide-load characteristics as claimed in claim 1, wherein The TMR detection module further includes a temperature sensor, which is used to detect the working temperature of the TMR sensor.

4. The switching system for improving the TMR measurement accuracy and expanding the wide-load characteristics according to claim 3, wherein The algorithm unit is used to perform temperature compensation according to the working temperature of the TMR sensor collected by the TMR detection module to ensure that the TMR sensor can maintain a stable and accurate measurement working state in different temperature environments.

5. The switching system for improving the TMR measurement accuracy and expanding the wide-load characteristics as claimed in claim 4, wherein The algorithm unit realizes the temperature compensation of the TMR sensor by correcting the zero offset and correcting the sensitivity attenuation.

6. The switching system for improving the TMR measurement accuracy and expanding the wide-load characteristics as described in claim 1, wherein The algorithm unit is used to perform excellent working section selection control according to the signal output by the amplification and acquisition unit, analyze the characteristics of the digital signal according to a preset threshold, and judge the current working state of the current TMR sensor.

7. The switching system for improving the TMR measurement accuracy and expanding the wide-load characteristics according to claim 1, wherein The amplification and acquisition unit includes a plurality of amplification and acquisition modules. Each amplification and acquisition module is connected to a TMR sensor. Each amplification and acquisition module includes a differential amplification circuit, an ADC sampling circuit, and an amplifier. The differential amplification circuit is used to amplify the signal; the ADC sampling circuit is used to perform analog-to-digital conversion on the amplified signal, and the amplifier is used to further amplify the digital signal after the analog-to-digital conversion.

8. The switching system for improving the TMR measurement accuracy and expanding the wide-load characteristics according to claim 1, wherein In the TMR sensor, the calculation formula for the change of magnetic field intensity with distance is: Among them, B is the magnetic field strength, μ 0 is the magnetic permeability of vacuum, I is the current, R is the distance between the TMR sensor and the magnetic field source.

9. The switching system for improving the TMR measurement accuracy and expanding the wide-load characteristics according to claim 1, wherein, The control unit is used to receive the feedback instruction from the algorithm unit and select the TMR sensor working in the excellent working section according to the feedback instruction.

10. The switching system for improving the TMR measurement accuracy and expanding the wide-load characteristics as claimed in claim 9, wherein The plurality of TMR sensors are respectively arranged at different positions from the magnetic field source. When the distance of the first TMR sensor from the magnetic field source is less than the distance of the second TMR sensor from the magnetic field source, the algorithm unit is used to judge the current working state of the first TMR sensor based on the digital signal output by the amplification and acquisition unit. When the first TMR sensor works in a non-excellent working section, a feedback instruction is sent to the control unit; The control unit is used to receive the feedback instruction from the algorithm unit and switch the second TMR sensor to work according to the feedback instruction. The algorithm unit is used to judge the current working state of the second TMR sensor based on the digital signal output by the amplification and acquisition unit. When the second TMR sensor works in the excellent working section, the control unit controls to switch the second TMR sensor to work and sends a signal to the inverter output unit.

11. The switching system for improving the TMR measurement accuracy and expanding the wide-load characteristics as described in claim 10, wherein The switching system further includes an inverter output unit, which receives the signal from the control unit, converts direct current into alternating current, and amplifies it to the required output voltage to achieve the final output.

12. The switching system for improving the TMR measurement accuracy and expanding the wide-load characteristics according to claim 11, wherein The inverter output unit uploads the measurement result and working state information to the host computer in real time through the wireless transmission module.

13. A switching method for improving the TMR measurement accuracy and expanding the wide-load characteristics, which is applied to the switching system for improving the TMR measurement accuracy and expanding the wide-load characteristics according to any one of claims 1-12, characterized in that The method includes: Using the first TMR sensor to sense the magnetic field change of the current to be measured and converting the sensed magnetic flux into an electrical signal; Amplifying the electrical signal and converting the amplified electrical signal into a digital signal; Judging the current working state of the first TMR sensor according to the output digital signal. When the first TMR sensor works in the non-excellent working section, switch to the second TMR sensor to sense the magnetic field change of the current to be measured, so that the TMR sensor in the excellent working section works, wherein the distances of the first TMR sensor and the second TMR sensor from the magnetic field source are different.

14. The switching method for improving the TMR measurement accuracy and expanding the wide-load characteristics according to claim 13, characterized in that The distance of the first TMR sensor from the magnetic field source is less than the distance of the second TMR sensor from the magnetic field source.

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