A magnetic field triggered low power wireless current detection system

Abstract

The application discloses a kind of magnetic field trigger type low-power wireless current detection systems, it is related to low-power wireless current detection field, the system includes: power management module, sensing acquisition module, self-calibration module, wireless communication module and microcontroller;Power management module includes normal power supply branch and controllable power supply branch;Sensing acquisition module includes switch type tunnel magnetoresistance sensor and linear type tunnel magnetoresistance sensor;Self-calibration module is connected with microcontroller and linear type tunnel magnetoresistance sensor;Microcontroller is used to respond trigger signal, control the on-off of controllable power supply branch, control the calibration process of self-calibration module, acquire and process the signal of linear type tunnel magnetoresistance sensor.It can give consideration to low-power operation, AC and DC current measurement, online self-calibration capability, improve the intelligent level and operation and maintenance efficiency of power equipment state monitoring.

Description

Technical Field

[0001] This invention relates to the field of low-power wireless current detection, and more specifically to a magnetic field-triggered low-power wireless current detection system. Background Technology

[0002] In the field of condition monitoring and fault diagnosis of high-voltage switchgear, accurate detection of the secondary circuit currents of circuit breaker opening and closing coils, energy storage motors, etc., is a key means to assess their mechanical characteristics and achieve predictive maintenance.

[0003] Existing detection devices mostly use continuously powered sensing and acquisition circuits, resulting in high overall system power consumption. This makes it difficult to operate for extended periods in situations with limited battery power or energy access. Although there have been attempts at low-power designs, most solutions still require the sensing unit to operate continuously or rely on complex external wake-up mechanisms. They cannot achieve reliable response to changes in external current while ensuring extremely low static power consumption. Furthermore, traditional current transformers based on electromagnetic induction are not suitable for measuring DC components or slowly varying currents, limiting their application in all current-type monitoring scenarios.

[0004] Regarding the maintenance of measurement accuracy, existing equipment is often affected by factors such as temperature drift, component aging, and installation stress, requiring regular on-site calibration. This not only results in high maintenance costs but also makes it difficult to guarantee the reliability of data within the calibration cycle. Although there are some self-calibration designs, they are mostly limited to single-point calibration or rely on external standard sources, making it impossible to achieve fully automatic, multi-point online gain and zero-point calibration after equipment installation. It is also difficult to effectively separate the measured current from on-site interference.

[0005] In addition, the intelligent transformation of existing equipment such as substations and switchgear often requires installation without interrupting power or altering the original wiring. Existing detection devices mostly use enclosed current transformers or need to be connected in series in the circuit, making the installation process complicated and difficult to deploy in a compact space. Although open-type current transformers have been used, they usually do not have integrated and wireless data acquisition and communication capabilities, making it difficult to form a monitoring system that can be flexibly networked.

[0006] Therefore, how to design a magnetic field-triggered low-power wireless current detection system that can balance low-power operation, AC / DC current measurement, and online self-calibration capabilities, in order to improve the intelligence level of power equipment condition monitoring and operation and maintenance efficiency, is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the present invention provides a magnetic field triggered low-power wireless current detection system, which aims to solve the problems of complex wiring, high power consumption, need for regular manual calibration, inability to measure DC current, and difficulty in modifying existing equipment in traditional current detection devices, so as to improve the intelligence level and operational reliability of power equipment status monitoring.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A magnetic field-triggered low-power wireless current detection system includes: Power management module: includes independent constant power supply branch and controllable power supply branch; Sensing and acquisition module: including switch-type tunnel magnetoresistive sensor and linear tunnel magnetoresistive sensor; Self-calibration module: Connected to the microcontroller and linear tunnel magnetoresistive sensor, it is used to apply at least two known calibration reference magnetic fields to the linear tunnel magnetoresistive sensor to automatically calibrate the measurement gain and zero point; Wireless communication module: Connected to the microcontroller, it is used to wirelessly transmit the current data and device status information processed by the microcontroller to a remote receiving device; Microcontroller: Used to respond to trigger signals, control the on / off state of controllable power supply branches, control the calibration process of the self-calibration module, and acquire and process signals from linear tunnel magnetoresistive sensors.

[0010] Preferably, the power management module further includes a lithium battery interface and a USB charging management circuit.

[0011] Preferably, both the constant power supply branch and the controllable power supply branch are implemented by low dropout linear regulators, and the enable terminal of the controllable power supply branch is connected to the general-purpose input / output pin of the microcontroller.

[0012] Preferably, in the sensing and acquisition module, the switch-type tunnel magnetoresistive sensor is connected to the constant power supply branch to monitor the magnetic field changes around the current-carrying conductor under test, and outputs a trigger signal to the microcontroller when the magnetic field change exceeds a preset threshold; the linear tunnel magnetoresistive sensor is connected to the controllable power supply branch to acquire the magnetic field signal generated by the current of the current-carrying conductor under test after the microcontroller receives the trigger signal.

[0013] Preferably, the sensing acquisition module further includes a signal conditioning circuit, which is connected between the output terminal of the linear tunnel magnetoresistive sensor and the input terminal of the analog-to-digital converter of the microcontroller, and is used to amplify and filter the voltage signal output by the linear tunnel magnetoresistive sensor.

[0014] Preferably, the self-calibration module includes a constant current source circuit, which, under the control of the microcontroller, outputs at least two different constant currents. and The magnetic field generated by the calibration coil acts on the linear tunnel magnetoresistive sensor.

[0015] Preferably, the self-calibration module further includes an open / closed state detection circuit, which is used to detect whether the current detection system is properly closed on the current-carrying conductor being measured, and to notify the microcontroller when a change in the closed state is detected.

[0016] Preferably, the automatic calibration method performed by the self-calibration module includes the following steps: Obtain the first output value of the linear tunnel magnetoresistive sensor when no current flows through the calibration coil. ; Control the constant current source to output the first calibration current To the calibration coil, obtain the second output value of the linear tunnel magnetoresistive sensor. ; Control the constant current source to output the second calibration current The third output value of the linear tunnel magnetoresistive sensor is obtained by calibrating the coil. ; according to and Two sets of data were used to calculate the gain coefficient K of the sensor acquisition module and the zero-point offset using a linear fitting algorithm. ; In subsequent current measurements, the measured current value is calculated. , This is the sampled output value.

[0017] Preferably, the wireless communication module uses a LoRa modulated radio frequency chip and operates in the ISM unlicensed frequency band.

[0018] Preferably, the system is encapsulated in an open housing with a U-shaped or C-shaped magnetic circuit channel through which the current-carrying conductor under test passes; both the switch-type tunnel magnetoresistive sensor and the linear tunnel magnetoresistive sensor are arranged at the gap in the magnetic circuit channel to sense the magnetic field generated by the current in the current-carrying conductor under test.

[0019] As can be seen from the above technical solution, compared with the prior art, the technical solution of the present invention has the following beneficial effects: 1. The system maintains the operation of the switching tunnel magnetoresistive sensor and microcontroller through the constant power supply branch, while the controllable power supply branch is activated only when the magnetic field change exceeds the threshold to supply power to the linear tunnel magnetoresistive sensor and signal conditioning circuit. This dual-path time-sharing power supply mechanism avoids the energy consumption caused by the continuous operation of the linear sensor, reduces the overall power consumption of the system, and extends the continuous operation time of the equipment in scenarios without external power supply or battery power supply.

[0020] 2. It uses a tunnel magnetoresistive sensor as the sensing core, and its response is not limited by the current frequency. It overcomes the limitation of traditional current transformers that are only suitable for AC measurement. With the open shell and U-shaped / C-shaped magnetic circuit channel, it can be directly installed on the conductor being measured without disconnecting the original line, which is convenient for intelligent transformation and online monitoring of existing power equipment.

[0021] 3. With a built-in constant current source and calibration coil, a known standard magnetic field can be applied to the sensor at startup or periodically. Gain and zero-point parameters can be obtained in real time through multi-point fitting, effectively suppressing the influence of temperature drift, mechanical stress and external interference on measurement accuracy. This self-calibration mechanism reduces the need for manual intervention and on-site calibration, and improves the stability and data reliability of the equipment in long-term operation. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0023] Figure 1 This is a framework diagram of a magnetic field-triggered low-power wireless current detection system provided in an embodiment of the present invention; Figure 2 This is a circuit structure diagram of a power management module provided in an embodiment of the present invention; Figure 3 This is a circuit structure diagram of the sensing acquisition module provided in an embodiment of the present invention; Figure 4 This is a circuit structure diagram of the self-calibration module provided in an embodiment of the present invention; Figure 5 A circuit structure diagram of a wireless communication module provided in an embodiment of the present invention; Figure 6 A microcontroller circuit structure diagram provided for an embodiment of the present invention; Figure 7 This is a schematic diagram of an open-type shell structure provided in an embodiment of the present invention; Figure 8 The flowchart illustrates a magnetic field-triggered low-power wireless current detection method provided in this embodiment of the invention. Detailed Implementation

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

[0025] like Figure 1 As shown, this embodiment provides a magnetic field-triggered low-power wireless current detection system, including: Power management module: includes independent constant power supply branch and controllable power supply branch; The sensing and acquisition module includes a switched tunnel magnetoresistive sensor and a linear tunnel magnetoresistive sensor. The switched tunnel magnetoresistive sensor is connected to the constant power supply branch and is used to monitor the magnetic field changes around the current-carrying conductor under test. When the magnetic field change exceeds a preset threshold, it outputs a trigger signal to the microcontroller. The linear tunnel magnetoresistive sensor is connected to the controllable power supply branch and is used to acquire the magnetic field signal generated by the current in the current-carrying conductor under test after the microcontroller receives the trigger signal. Self-calibration module: Connected to the microcontroller and linear tunnel magnetoresistive sensor, it is used to apply at least two known calibration reference magnetic fields to the linear tunnel magnetoresistive sensor to automatically calibrate the measurement gain and zero point; Wireless communication module: Connected to the microcontroller, it is used to wirelessly transmit the current data and device status information processed by the microcontroller to a remote receiving device; Microcontroller: Used to respond to trigger signals, control the on / off state of the controllable power supply branch, control the calibration process of the self-calibration module, acquire and process signals from the linear tunnel magnetoresistive sensor, and control the data transmission of the wireless communication module.

[0026] This system achieves extremely low power consumption by using a constant power supply and controllable time-sharing power supply mechanism combined with magnetic field triggering wake-up; it adopts a tunnel magnetoresistive sensor and an open magnetic circuit structure to support non-invasive measurement of AC and DC current; and it has a built-in constant current self-calibration function that can automatically compensate for gain and zero drift during operation, improving the accuracy and reliability of long-term measurements. It is suitable for long-term online monitoring and intelligent transformation of high-voltage switchgear and other field applications.

[0027] The following provides a further detailed description of the various structures and related features in the above system; In this embodiment, the power management module also includes a lithium battery interface and a USB charging management circuit. Both the constant power supply branch and the controllable power supply branch are implemented by a low dropout linear regulator. The enable terminal of the controllable power supply branch is connected to the general-purpose input / output pin of the microcontroller.

[0028] Specifically, the implementation of the power management module can be as follows: Figure 2 As shown, the lithium battery interface BAT provides DC input, and the USB1 interface, together with the charging management chip U5, enables safe charging and reverse protection of the lithium battery; the constant power supply branch is implemented by the low dropout linear regulator U6, whose input is connected to the lithium battery and outputs a stable 3.3V to power the MCU and normally open circuits such as the switch TMR. The controllable power supply branch is implemented by U7. The enable terminal EN of this branch is connected to the GPIO pin of the microcontroller U2. When the MCU sets this pin to a high level, U7 outputs an active signal, supplying power to the linear TMR, operational amplifier and other measurement circuits. When set to a low level, U7 is turned off, cutting off the power supply to the measurement circuit, thereby realizing time-sharing power supply and power consumption control.

[0029] In this embodiment, the sensing acquisition module further includes a signal conditioning circuit, which is connected between the output terminal of the linear tunnel magnetoresistive sensor and the input terminal of the analog-to-digital converter of the microcontroller, and is used to amplify and filter the voltage signal output by the linear tunnel magnetoresistive sensor.

[0030] Specifically, the sensor acquisition module can be implemented as follows: Figure 3 As shown, its signal conditioning circuit is integrated into the current acquisition system circuit. The differential voltage signal output by the linear TMR sensor U1 is connected to the input of the operational amplifier. This operational amplifier circuit is usually configured as an instrumentation amplifier or differential amplifier circuit to amplify the weak TMR output signal and suppress common-mode interference. The amplified single-ended voltage signal passes through a low-pass filter composed of resistors and capacitors to filter out high-frequency noise. The conditioned analog signal is finally sent to the ADC input pin of the microcontroller, where the MCU performs analog-to-digital conversion to convert the analog voltage value into a digital quantity that can be processed. The output of the switch-type tunnel magnetoresistive sensor U4 is connected to the constant power supply branch to monitor the magnetic field changes around the current-carrying conductor being measured, and outputs a trigger signal to the microcontroller when the magnetic field change exceeds a preset threshold.

[0031] In this embodiment, the self-calibration module includes a constant current source circuit and an open / closed state detection circuit; The opening / closing state detection circuit is used to detect whether the current detection system is properly closed on the current-carrying conductor being measured, and to notify the microcontroller when a change in the closing state is detected. The constant current source circuit, under the control of the microcontroller, outputs at least two different constant currents. and The magnetic field generated by the calibration coil acts on the linear tunnel magnetoresistive sensor.

[0032] The specific hardware implementation of the self-calibration module can be as follows: Figure 4 As shown, the opening / closing state detection circuit is implemented by micro switch SW1; when the sensor housing latch is closed, SW1 is pressed down, and its output signal changes from high level to low level (or vice versa). This state change is connected to the microcontroller's GPIO interrupt pin to trigger the system startup or recalibration process. The constant current source circuit consists of voltage reference chips U8 and U9, operational amplifiers, transistors, etc. Under the control of the microcontroller, the circuit can output two constant currents with high stability and low temperature drift. These two currents flow through a common calibration coil. During the calibration process, the coil is placed close to the linear TMR sensor to generate a precise and known reference magnetic field.

[0033] In this embodiment, the automatic calibration method performed by the self-calibration module includes the following steps: Obtain the first output value of the linear tunnel magnetoresistive sensor when no current flows through the calibration coil. ; Control the constant current source to output the first calibration current To the calibration coil, obtain the second output value of the linear tunnel magnetoresistive sensor. ; Control the constant current source to output the second calibration current The third output value of the linear tunnel magnetoresistive sensor is obtained by calibrating the coil. ; according to and Two sets of data were used to calculate the gain coefficient K of the sensor acquisition module and the zero-point offset using a linear fitting algorithm. ; In subsequent current measurements, the measured current value is calculated. , This is the sampled output value.

[0034] The self-calibration method here is executed by microcontroller U2, which controls the constant current source circuits U8 and U9 to work together. First, the MCU controls the constant current source to turn off. At this time, there is no current in the calibration coil. The MCU acquires the output voltage of the linear TMR at this time through its ADC, which is denoted as... Next, the MCU controls the constant current source via its GPIO or DAC to output the first level of calibration current. After the calibration coil stabilizes, the TMR output voltage is measured. Similarly, output the second level of calibration current. Collect voltage; Get and After obtaining two sets of net output values ​​relative to zero, the MCU internally runs a linear fitting algorithm, which uses known values... and Using the x-axis as the horizontal axis and the corresponding net output value as the y-axis, the current gain coefficient K (slope) and equivalent zero offset of the system are calculated using the two-point formula or the least squares method. (Intercept), this K and It will be stored in the MCU's memory for real-time compensation of all subsequent measurement data.

[0035] In this embodiment, the wireless communication module uses a LoRa modulated radio frequency chip and operates in the ISM unlicensed frequency band.

[0036] The specific implementation of the wireless communication module can be as follows: Figure 5 As shown, it is an RF chip L1 that supports LoRa modulation. It is connected to the SPI pin of the microcontroller through the SPI interface to receive data transmission control from the MCU. The chip's antenna interface is connected to a PCB antenna or an external antenna for radiating and receiving radio waves. This wireless module operates in ISM unlicensed frequency bands, such as 470MHz, 868MHz, or 915MHz. Under the instructions of the microcontroller, the module packages the current data, heartbeat messages, and other information to be sent, modulates them according to the LoRaWAN protocol or a custom communication frame format, and sends them to the terminal device through the antenna. It features long transmission distance and strong anti-interference capability, making it suitable for data backhaul in complex electromagnetic environments such as substations.

[0037] In this embodiment, the specific implementation of the microcontroller can be as follows: Figure 6 As shown, its core is a low-power microcontroller U2. The power supply pin VCC of this microcontroller is connected to the VCC terminal of the constant power supply branch, ensuring that it is always powered on. Its multiple general-purpose input / output (GPIO) pins are assigned key functions: for example, the PA1 pin is connected to the enable terminal EN of the controllable power supply branch U7 to control the power supply of the measurement circuit; another GPIO pin is connected to the output terminal of the linear TMR and configured as an external interrupt input to receive magnetic field trigger signals; in addition, the input channel of its built-in 12-bit high-precision analog-to-digital converter (ADC) is connected to the output of the signal conditioning circuit to acquire current and voltage signals; and the pin of its serial peripheral interface (SPI) is connected to the corresponding interface of the LoRa wireless module L1 for data transmission.

[0038] In terms of control flow, after power-on, the microcontroller U2 first completes initialization and then enters low-power mode. At this time, most of its peripherals and clock are in sleep mode, and only the necessary wake-up source activities are retained to maintain extremely low standby current. When an interrupt is generated due to the TMR switch trigger, the MCU is woken up and immediately executes the interrupt service routine: the PA1 pin is set high to enable U7, which supplies power to the linear TMR and operational amplifier; then the ADC is controlled to sample the current signal; after sampling, it can decide whether to start the self-calibration process according to preset conditions (by controlling U8 and U9); after data processing is completed, the data is sent to the wireless module L1 via SPI; finally, after confirming that the data transmission is complete or a timeout has occurred, the microcontroller shuts down U7 and reconfigures itself to enter low-power mode, waiting for the next trigger, thereby realizing precise coordinated control of the entire system's workflow and power consumption status.

[0039] In this embodiment, as Figure 7 As shown, the system is encapsulated in an open housing with a U-shaped or C-shaped magnetic circuit channel through which the current-carrying conductor under test passes. Both the switch-type tunnel magnetoresistive sensor and the linear tunnel magnetoresistive sensor are arranged at the gap in the magnetic circuit channel to sense the magnetic field generated by the current in the current-carrying conductor under test.

[0040] Furthermore, such as Figure 8 As shown, this embodiment provides a magnetic field-triggered low-power wireless current detection method, including the following steps: S1. System initialization: The microcontroller and the switch-type tunnel magnetoresistive sensor are powered by the constant power supply branch, entering a low-power standby mode, and the controllable power supply branch is kept off. S2. When the calibration conditions are met, perform the self-calibration step to obtain the gain coefficient and zero offset of the current measurement channel. S3. The magnetic field change around the current-carrying conductor under test is continuously monitored by a switch-type tunnel magnetoresistive sensor. When the magnetic field change exceeds a preset threshold, a trigger signal is output to the microcontroller. S4. The microcontroller responds to the trigger signal and controls the controllable power supply branch to conduct, providing power to the linear tunnel magnetoresistive sensor and signal conditioning circuit. S5. The current magnetic field signal is acquired by a linear tunnel magnetoresistive sensor, and the current sampling data is obtained after signal conditioning and analog-to-digital conversion. S6. The microcontroller processes the current sampling data using the gain coefficient and zero offset to obtain the measured current value. S7. The microcontroller sends the measured current value through the wireless communication module; S8. After the transmission is completed, the microcontroller controls the controllable power supply branch to shut down, and the system returns to the low-power standby mode.

[0041] The magnetic field-triggered low-power wireless current detection method in this embodiment achieves extremely low power consumption operation of the system while ensuring the accuracy of current measurement through a collaborative workflow of time-sharing power supply control, magnetic field-triggered wake-up, automatic calibration compensation and wireless data transmission. It effectively solves the problems of high power consumption, need for manual calibration and inconvenient installation in the prior art, and provides a reliable and flexible online current monitoring solution for high-voltage switchgear and other scenarios.

[0042] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0043] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A magnetic field-triggered low-power wireless current detection system, characterized in that, include: Power management module: includes independent constant power supply branch and controllable power supply branch; Sensing and acquisition module: including switch-type tunnel magnetoresistive sensor and linear tunnel magnetoresistive sensor; Self-calibration module: Connected to the microcontroller and linear tunnel magnetoresistive sensor, it is used to apply at least two known calibration reference magnetic fields to the linear tunnel magnetoresistive sensor to automatically calibrate the measurement gain and zero point; Wireless communication module: Connected to the microcontroller, it is used to wirelessly transmit the current data and device status information processed by the microcontroller to a remote receiving device; Microcontroller: Used to respond to trigger signals, control the on / off state of controllable power supply branches, control the calibration process of the self-calibration module, and acquire and process signals from linear tunnel magnetoresistive sensors.

2. The magnetic field-triggered low-power wireless current detection system according to claim 1, characterized in that, The power management module also includes a lithium battery interface and a USB charging management circuit.

3. The magnetic field-triggered low-power wireless current detection system according to claim 1, characterized in that, Both the constant power supply branch and the controllable power supply branch are implemented by low dropout linear regulators, and the enable terminal of the controllable power supply branch is connected to the general-purpose input / output pin of the microcontroller.

4. The magnetic field-triggered low-power wireless current detection system according to claim 1, characterized in that, In the sensing and acquisition module, the switch-type tunnel magnetoresistive sensor is connected to the constant power supply branch to monitor the magnetic field change around the current-carrying conductor under test, and outputs a trigger signal to the microcontroller when the magnetic field change exceeds a preset threshold. The linear tunnel magnetoresistive sensor is connected to the controllable power supply branch and is used to acquire the magnetic field signal generated by the current in the current-carrying conductor after the microcontroller receives the trigger signal.

5. The magnetic field-triggered low-power wireless current detection system according to claim 1, characterized in that, The sensing acquisition module also includes a signal conditioning circuit, which is connected between the output terminal of the linear tunnel magnetoresistive sensor and the input terminal of the analog-to-digital converter of the microcontroller, and is used to amplify and filter the voltage signal output by the linear tunnel magnetoresistive sensor.

6. The magnetic field-triggered low-power wireless current detection system according to claim 1, characterized in that, The self-calibration module includes a constant current source circuit, which, under the control of the microcontroller, outputs at least two different constant currents. and The magnetic field generated by the calibration coil acts on the linear tunnel magnetoresistive sensor.

7. The magnetic field-triggered low-power wireless current detection system according to claim 1, characterized in that, The self-calibration module also includes an open / closed state detection circuit, which is used to detect whether the current detection system is properly closed on the current-carrying conductor being measured, and to notify the microcontroller when a change in the closed state is detected.

8. The magnetic field-triggered low-power wireless current detection system according to claim 1, characterized in that, The automatic calibration method performed by the self-calibration module includes the following steps: Obtain the first output value of the linear tunnel magnetoresistive sensor when no current flows through the calibration coil. ; Control the constant current source to output the first calibration current To the calibration coil, obtain the second output value of the linear tunnel magnetoresistive sensor. ; Control the constant current source to output the second calibration current The third output value of the linear tunnel magnetoresistive sensor is obtained by calibrating the coil. ; according to and Two sets of data were used to calculate the gain coefficient K of the sensor acquisition module and the zero-point offset using a linear fitting algorithm. ; In subsequent current measurements, the measured current value is calculated. , This is the sampled output value.

9. The magnetic field-triggered low-power wireless current detection system according to claim 1, characterized in that, The wireless communication module uses a LoRa modulated radio frequency chip and operates in the ISM unlicensed frequency band.

10. A magnetic field-triggered low-power wireless current detection system according to claim 1, characterized in that, The system is encapsulated in an open housing with a U-shaped or C-shaped magnetic circuit channel through which the current-carrying conductor under test passes. Both the switch-type tunnel magnetoresistive sensor and the linear tunnel magnetoresistive sensor are arranged at the gaps in the magnetic circuit channel to sense the magnetic field generated by the current in the current-carrying conductor under test.

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