Digital output current measurement method and system based on TMR array

Abstract

The invention discloses a digital output current measurement method and system based on a TMR array, and the method comprises the steps: obtaining a secondary analog voltage signal which is output by a TMR rectangular array at a t moment and is in direct proportion to a primary measured current signal, and carrying out the low-pass filtering and high-pass filtering, thereby obtaining a low-frequency voltage signal and a high-frequency voltage signal; under the triggering of a sampling clock, after analog-to-digital conversion and Fourier transform are carried out on the low-frequency voltage signal and the high-frequency voltage signal, a power-frequency current signal and a high-frequency current signal measured by a TMR current sensor are obtained, and delay error sampling time caused by desynchrony between an analog-to-digital conversion sampling clock signal and a trigger signal is analyzed; acquiring the microprocessing time of the microprocessor for the low-frequency discrete voltage signal and the high-frequency discrete voltage signal; and performing correction according to a phase error caused by the delay error sampling time and the micro-processing time, and encoding the corrected measurement data to obtain a corresponding digital output current.

Description

Technical Field

[0001] The present application relates to the field of electric power technology, and in particular to a digital output current measurement method and system based on a TMR array. Background Art

[0002] With the development of power systems characterized by the access of a high proportion of new energy and power electronic equipment, modern society has put forward more requirements for the safety, stability and efficiency of power grids. Therefore, more intelligent detection equipment has been introduced to access the power grid, making the traditional power grid rapidly transform into a smart grid. Smart grid is a new power system that combines traditional physical grid technology with modern digital technology, and uses advanced means such as modern communication technology, intelligent sensing technology, information technology and intelligent control technology to achieve a more reliable, safer, more economical, more efficient and more environmentally friendly. Advanced sensing technology is the foundation of smart grid technology and an important technical support for the realization of smart grids. As one of the most basic state quantities of power data, accurate and reliable detection of current is of great significance. At the same time, in order to meet the needs of the development of smart grids, current measurement should have the characteristics of high precision, low cost and easy installation.

[0003] The current sensors currently used in power systems mainly include electromagnetic current transformers, Rogowski coils, shunts, all-fiber current transformers, and magnetic sensing technology. The research on electromagnetic current transformers is mainly used in the measurement of power frequency current signals. Magnetic saturation is prone to occur when measuring high-frequency signals, and the measurement accuracy is easily affected by DC bias magnetism. It is difficult to ensure the measurement accuracy requirements when electromagnetic current transformers measure broadband dynamic signals. Rogowski coils cannot be accurately measured under low-frequency AC current due to large attenuation and phase delay, and their measurement accuracy is easily affected by the eccentricity of the measured line. The shunt is based on Ohm's law. When measuring AC current, the parasitic inductance and capacitance of the shunt make its impedance change with frequency, affecting the accurate measurement of broadband current signals. The all-fiber current transformer uses the Faraday magneto-optical effect of the optical fiber material itself to measure current. Compared with the traditional winding current transformer, it solves the defects of core saturation, high cost and small measurement range, but it is easily affected by the environment and has the problem of high economic cost, which is not suitable for large and wide AC power grids. The most widely used magnetic sensing technology is tunneling magnetoresistance (TMR) sensor, which has the characteristics of small size, light weight, low cost, no magnetic saturation and DC bias and non-contact design. However, TMR sensor is prone to phase deviation when digital output, resulting in measurement error. Therefore, TMR current sensor needs to explore new methods to solve the phase deviation problem of digital output current in order to achieve stable and accurate measurement. Summary of the invention

[0004] In view of this, an embodiment of the present application provides a digital output current measurement method and system based on a TMR array.

[0005] According to one aspect of the present application, a digital output current measurement method based on a TMR array is provided, the method comprising: Obtaining a secondary analog voltage signal proportional to the primary measured current signal output by the TMR rectangular array at time t; Based on the secondary analog voltage signal, low-pass filtering and high-pass filtering are performed to obtain a low-frequency voltage signal and a high-frequency voltage signal output by the TMR current sensor at time t; Under the triggering of the sampling clock, the low-frequency voltage signal and the high-frequency voltage signal are converted into analog-to-digital signals to obtain the converted low-frequency discrete voltage signal and high-frequency discrete voltage signal. After Fourier transformation, the industrial frequency current signal and the high-frequency current signal measured by the TMR current sensor are obtained, and the delay error sampling time caused by the asynchronism between the analog-to-digital conversion sampling clock signal and the trigger signal is analyzed. ; According to the low-frequency discrete voltage signal and the high-frequency discrete voltage signal after analog-to-digital conversion, a microprocessor is used to perform digital signal microprocessing, and the microprocessor microprocessing time of the low-frequency discrete voltage signal and the high-frequency discrete voltage signal is obtained through clock sampling. ; According to the delay error sampling time and the microprocessing time The phase error caused is corrected to obtain a corrected power frequency current signal and a corrected high frequency current signal as corrected measurement data; The corrected measurement data is encoded to obtain the corresponding digital output current.

[0006] According to another aspect of the present application, a digital output current measurement system based on a TMR array is provided, for executing the above method, the system comprising: The TMR rectangular array includes four groups of TMR chips, and is used to obtain a secondary analog voltage signal of the measured circuit at time t that is proportional to the primary measured current signal; The analog signal processing module is used to perform low-pass analog filtering and high-pass analog filtering on the two outputs of the TMR current sensor in parallel based on the output signal of the TMR rectangular array, and obtain the low-frequency voltage signal and high-frequency voltage signal output by the TMR current sensor at time t; The synchronous clock generation module is used to output two synchronous second pulse signals to trigger two 24-bit analog-to-digital converters to digitally convert analog voltage signals; The analog-to-digital conversion module is composed of two 24-bit analog-to-digital converters. The two 24-bit analog-to-digital converters are used to perform analog-to-digital conversion on low-frequency voltage signals and high-frequency voltage signals under the triggering of a sampling clock to obtain corresponding low-frequency discrete voltage signals and high-frequency discrete voltage signals; The clock timing module uses TDC conversion technology to obtain the delay error sampling time caused by the asynchronization between the analog-to-digital conversion sampling clock signal and the trigger signal. and the microprocessing time of digital signal microprocessor ; A digital signal microprocessing module is used to sample the time according to the delay error. and the microprocessing time The phase error caused is corrected to obtain a corrected power frequency current signal and a corrected high frequency current signal as corrected measurement data; the corrected measurement data is encoded to obtain a corresponding digital output current.

[0007] According to another aspect of the present application, a storage medium is provided, on which a computer program is stored. When the program is executed by a processor, the above-mentioned digital output current measurement method based on the TMR array is implemented.

[0008] According to another aspect of the present application, a computer device is provided, including a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, wherein the processor implements the above-mentioned digital output current measurement method based on the TMR array when executing the program.

[0009] By means of the above technical solution, the embodiment of the present application provides a digital output current measurement method and system based on a TMR array, which obtains the delay error sampling time of the analog-to-digital conversion. , determine the delay error phase angle caused by the analog-to-digital conversion process, and correct the delay error phase angle of the analog-to-digital conversion according to the low-frequency current and high-frequency current signals after Fourier transformation, solving the phase delay error caused by the analog-to-digital conversion sampling clock signal and the trigger signal not being strictly synchronized, which can improve the measurement reliability of the TMR current sensor. Using TDC conversion technology, a micro-nano time measurement method based on the counter method is used to measure the micro-processing time of the digital signal microprocessor from receiving the discrete voltage signal to outputting the processed discrete voltage signal. , and the microprocessing time The phase information is converted into phase information, and the low-frequency and high-frequency discrete signals are corrected in the digital signal microprocessor module, which ensures that the digital signal microprocessor has no influence on the microprocessing process and can effectively improve the measurement accuracy of the TMR current sensor.

[0010] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1 A schematic flow chart of a digital output current measurement method based on a TMR array provided in an embodiment of the present application is shown; Figure 2 A schematic diagram of the structure of a TMR array provided in an embodiment of the present application is shown; Figure 3 A schematic diagram of analog-to-digital conversion trigger sampling equivalent timing provided by an embodiment of the present application is shown; Figure 4 A structural schematic diagram of a digital output current measurement system based on a TMR array provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0012] The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0013] In this embodiment, a digital output current measurement method based on a TMR array is provided. Figure 1 As shown, the method includes: Step 101: Obtain a secondary analog voltage signal proportional to a primary measured current signal output by the TMR rectangular array at time t.

[0014] Among them, Figure 2 As shown, the TMR rectangular array is a TMR current sensor composed of four groups of TMR chips, and the measured wire is placed at the center of the TMR rectangular array. It should be noted that the array structure TMR sensor is a new idea and another new method to replace the magnetic core structure TMR sensor. Four groups of TMR chips are selected to form a TMR rectangular array, which constitutes a TMR current sensor. The measured wire is placed at the ideal center of the rectangle. 0 The mark on the right is the conductor being tested.

[0015] Step 102: Perform low-pass filtering and high-pass filtering based on the secondary analog voltage signal to obtain a low-frequency voltage signal and a high-frequency voltage signal output by the TMR current sensor at time t.

[0016] Specifically, the secondary analog voltage signal output by the TMR current sensor Output two voltage signals in parallel and , the three signals satisfy the following relationship: ; For voltage signal Perform low-pass filtering to obtain the low-frequency voltage signal output by the TMR current sensor at time t ; For voltage signal Perform high-pass filtering to obtain the high-frequency voltage signal output by the TMR current sensor at time t .

[0017] Step 103: Under the triggering of the sampling clock, the low-frequency voltage signal and the high-frequency voltage signal are converted into analog-to-digital signals to obtain the converted low-frequency discrete voltage signal and high-frequency discrete voltage signal, and the power frequency current signal and high-frequency current signal measured by the TMR current sensor are obtained after Fourier transformation, and the delay error sampling time caused by the asynchronism between the analog-to-digital conversion sampling clock signal and the trigger signal is analyzed. .

[0018] Specifically, the synchronous clock unit outputs a single-channel second pulse signal F1, and the rising edge of F1 triggers the first 24-bit analog-to-digital conversion chip to convert the low-frequency voltage signal Trigger sampling to obtain the corresponding low-frequency discrete voltage signal , and The relationship between them is as follows: , , is the sampling rate of the first 24-bit analog-to-digital conversion chip; is the sampling point number of the low-frequency voltage signal, is the total number of sampling points of the low-frequency voltage signal; in order to ensure the accuracy of the acquisition of the low-frequency voltage signal, the sampling rate of the 24-bit high-precision analog-to-digital conversion device Generally taken as , number of sampling points Take it as 1024.

[0019] For the low frequency discrete voltage signal Perform Fourier transform to calculate low-frequency discrete voltage signal The corresponding power frequency component is used as the power frequency voltage signal , as shown below: , In the formula, is the peak value of the power frequency voltage output by the TMR current sensor at time t, is the initial phase of the power frequency voltage output by the TMR current sensor at time t; According to the power frequency voltage signal , calculate the power frequency current signal of the measured line , as shown below: , In the formula, is the peak value of the line power frequency current measured by the TMR current sensor at time t, is the initial phase of the line power frequency current measured by the TMR current sensor at time t; The synchronous clock unit outputs the second pulse signal F2, and the rising edge of F2 triggers the second 24-bit analog-to-digital conversion chip to convert the high-frequency voltage signal Perform trigger sampling to obtain the corresponding high-frequency discrete voltage signal , and The relationship between them is as follows: , , is the sampling rate of the second 24-bit analog-to-digital conversion chip; is the sampling point number of the high-frequency voltage signal, is the total number of sampling points of the high-frequency voltage signal; in order to ensure the accuracy of obtaining the high-frequency voltage signal, the sampling rate of the 24-bit high-speed analog-to-digital conversion device Generally taken as , number of sampling points Take it as 1024.

[0020] Based on high frequency discrete voltage signal Perform Fourier transform to calculate high-frequency discrete voltage signals The corresponding high-frequency voltage signal , as shown below: , In the formula, is the harmonic order of the high-frequency voltage signal, is the output of TMR at time t The peak value of the sub-high frequency harmonic voltage, is the output of the TMR current sensor at time t The initial phase of the subharmonic voltage; According to the high frequency voltage signal Calculate the high-frequency current signal of the measured line as shown in the following formula: , In the formula, It is the proportional coefficient of the TMR current sensor after calibration when the measured wire has no deflection angle, no eccentricity, and no external electromagnetic interference before leaving the factory. is the initial phase of the line power frequency current measured by the TMR current sensor at time t.

[0021] Furthermore, based on the delay error sampling time , calculate the phase deviation , as shown below: , where ( ) is the angular unit of minutes, and f is the frequency of the measured AC signal.

[0022] Generally speaking, when the trigger signal arrives, the analog-to-digital conversion module records the sampled data data0, data1, data2...datan after the next sampling clock under a specific sampling clock (n is the number of sampling bits of the analog-to-digital conversion). The equivalent timing diagram of the triggered sampling is as follows: Figure 3 As shown in the figure, it can be seen that the analog-to-digital conversion sampling clock signal and the trigger signal are not strictly synchronized, and there is a delay error sampling time. , that is, The trigger signal may be located between any sampling moments due to the offset of the crystal frequency and the influence of the ambient temperature, resulting in a non-fixed delay error, which further causes different analog-to-digital conversion sampling systems to still have phase errors under the trigger sampling of the synchronous clock. , ( ) is the angle unit, which affects the measurement reliability of the TMR current sensor. Assume that the frequency of the measured AC signal is f, and the sampling clock of the analog-to-digital conversion is , then the maximum value of the sampling delay error is: , then the maximum phase difference caused by sampling delay is: , ( ) is the angular unit of minutes.

[0023] Step 104: According to the low-frequency discrete voltage signal and the high-frequency discrete voltage signal after analog-to-digital conversion, a microprocessor is used to perform digital signal microprocessing, and the microprocessor microprocessing time of the low-frequency discrete voltage signal and the high-frequency discrete voltage signal is obtained by clock sampling. .

[0024] Further, based on microprocessing time , calculate the calibration value of the phase difference , as shown below: , ( ) is the angular unit of minutes.

[0025] Among them, based on the discrete voltage signal after digital-to-analog conversion and , the discrete voltage signal enters the digital signal microprocessor for signal microprocessing, and at the same time triggers the clock timing module. When the processed discrete voltage signal is output from the microprocessor, the clock timing module is triggered to stop, and the clock timing module obtains the microprocessing time ; Use a time conversion technology (Time to Digital Converter, referred to as TDC) to measure the time difference from the digital signal microprocessor receiving the discrete voltage signal to the output of the processed discrete voltage signal, and convert the time difference into phase information for correction. TDC is a micro-nano time measurement method based on the counter method. Its basic principle is to use a high-precision digital counter to count the pulse signal of a known frequency with the rising edge or falling edge of the measured signal as the starting time, and calculate the time difference until the end of the measured signal. Assume that the frequency of the high-frequency counting pulse is , the count value within the start and end time of the TDC counting gate signal is N, then the calibration value of the phase difference is: , it can be seen from the formula that the frequency of the high-frequency counting pulse The larger the value, the higher the measurement accuracy of the time difference and the more accurate the correction value of the phase difference.

[0026] Step 105: Sampling time according to the delay error and the microprocessing time The phase error caused is corrected to obtain a corrected power frequency current signal and a corrected high frequency current signal as corrected measurement data.

[0027] Specifically, based on the power frequency voltage signal and the high frequency voltage signal , the sampling time of the delay error after the digital-to-analog conversion The phase deviation caused The correction is calculated as follows: , In the formula, Indicates the phase deviation The corrected power frequency voltage signal, Indicates the phase deviation Corrected high frequency voltage signal; Microprocessor error time for digital signal The phase deviation caused The correction is calculated as follows: , In the formula, Indicates the calibrated value of the phase difference The corrected power frequency voltage signal, Indicates the calibrated value of the phase difference Corrected high frequency voltage signal; Calculate the corrected power frequency current signal of the measured line and high frequency current signals for: , where is the initial phase of the line power frequency current measured by the TMR current sensor at time t, is the line n measured by the TMR current sensor at time t H Initial phase of subharmonic current.

[0028] Step 106: Encode the corrected measurement data to obtain the corresponding digital output current.

[0029] Specifically, the corrected power frequency current signal is used as the measured value of the power frequency current signal of the line, and the corrected high frequency current signal is used as the measured value of the high frequency current signal of the line to obtain the digital output current. Among them, the encoding format of the digital output current signal includes: OXAA, OXFF, OXDA11, OXDA12, OXDA13, OXFA11, OXFA12, OXFA13, OXDA21, OXDA22, OXFA21, OXFA22, OXDA31, OXDA32, OXFA31, OXFA32, ..., OXDA601, OXDA602, OXFA601, OXFA602, OXAA, OX55; among them, OX represents hexadecimal, OXAA, OXFF are frame headers, OXDAi1, OXDAi2, OXDAi3 are measured values ​​of line power frequency current signals, OXFAi1, OXFAi2, OXFAi3 are measured values ​​of line high frequency current signals, i=1,...,60, OXAA, OX55 are frame tails.

[0030] By applying the technical solution of this embodiment, the delay error sampling time of analog-to-digital conversion is and the digital signal processing time of the microprocessor Correction is performed to eliminate the influence of the phase error generated by the voltage signal after signal processing on the overall measurement result, and the corrected measurement data is encoded and output to obtain a digital output current, which solves the problem of insufficient accuracy and stability of the existing TMR current sensing method and system.

[0031] Further, as Figure 1 The specific implementation of the method, the embodiment of the present application provides a digital output current measurement system based on a TMR array, which is used to implement the above method, such as Figure 4 As shown, the system includes: The TMR rectangular array includes four groups of TMR chips, and is used to obtain a secondary analog voltage signal of the measured circuit at time t that is proportional to the primary measured current signal; The analog signal processing module is used to perform low-pass analog filtering and high-pass analog filtering on the two outputs of the TMR current sensor in parallel based on the output signal of the TMR rectangular array, and obtain the low-frequency voltage signal and high-frequency voltage signal output by the TMR current sensor at time t; The synchronous clock generation module is used to output two synchronous second pulse signals to trigger two 24-bit analog-to-digital converters to digitally convert analog voltage signals; The analog-to-digital conversion module is composed of two 24-bit analog-to-digital converters. The two 24-bit analog-to-digital converters are used to perform analog-to-digital conversion on low-frequency voltage signals and high-frequency voltage signals under the triggering of a sampling clock to obtain corresponding low-frequency discrete voltage signals and high-frequency discrete voltage signals; The clock timing module uses TDC conversion technology to obtain the delay error sampling time caused by the asynchronization between the analog-to-digital conversion sampling clock signal and the trigger signal. and the microprocessing time of digital signal microprocessor ; A digital signal microprocessing module is used to sample the time according to the delay error. and the microprocessing time The phase error caused is corrected to obtain a corrected power frequency current signal and a corrected high frequency current signal as corrected measurement data; the corrected measurement data is encoded to obtain a corresponding digital output current.

[0032] It should be noted that for other corresponding descriptions of the functional units involved in the digital output current measurement system based on the TMR array provided in the embodiment of the present application, reference can be made to Figure 1 The corresponding description in the method will not be repeated here.

[0033] The embodiment of the present application also provides a computer device, which can be a personal computer, a server, a network device, etc. The computer device includes a bus, a processor, a memory and a communication interface, and can also include an input and output interface and a display device. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store location information. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, the steps in each method embodiment are implemented.

[0034] Those skilled in the art will appreciate that the structure of the above-mentioned computer device is only a partial structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components, or combine certain components, or have a different arrangement of components.

[0035] In one embodiment, a computer-readable storage medium is provided. The computer-readable storage medium may be non-volatile or volatile, and stores a computer program thereon. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0036] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0037] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0038] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0039] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0040] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A digital output current measurement method based on TMR array, characterized in that: The method comprises: Obtaining a secondary analog voltage signal proportional to the primary measured current signal output by the TMR rectangular array at time t; Based on the secondary analog voltage signal, low-pass filtering and high-pass filtering are performed to obtain a low-frequency voltage signal and a high-frequency voltage signal output by the TMR current sensor at time t; Under the triggering of the sampling clock, the low-frequency voltage signal and the high-frequency voltage signal are converted into analog-to-digital signals to obtain the converted low-frequency discrete voltage signal and high-frequency discrete voltage signal. After Fourier transformation, the industrial frequency current signal and the high-frequency current signal measured by the TMR current sensor are obtained, and the delay error sampling time caused by the asynchronism between the analog-to-digital conversion sampling clock signal and the trigger signal is analyzed. ; According to the low-frequency discrete voltage signal and the high-frequency discrete voltage signal after analog-to-digital conversion, a microprocessor is used to perform digital signal microprocessing, and the microprocessor microprocessing time of the low-frequency discrete voltage signal and the high-frequency discrete voltage signal is obtained through clock sampling. ; According to the delay error sampling time and the microprocessing time The phase error caused is corrected to obtain a corrected power frequency current signal and a corrected high frequency current signal as corrected measurement data; The corrected measurement data is encoded to obtain the corresponding digital output current.

2. The digital output current measurement method based on TMR array according to claim 1, characterized in that: The TMR rectangular array is a TMR current sensor composed of four groups of TMR chips, and the measured conductor is placed at the center of the TMR rectangular array.

3. The digital output current measurement method based on TMR array according to claim 2, characterized in that: Based on the secondary analog voltage signal, low-pass filtering and high-pass filtering are performed to obtain a low-frequency voltage signal and a high-frequency voltage signal output by the TMR current sensor at time t, including: The secondary analog voltage signal output by the TMR current sensor Output two voltage signals in parallel and , the three signals satisfy the following relationship: ; For voltage signal Perform low-pass filtering to obtain the low-frequency voltage signal output by the TMR current sensor at time t ; For voltage signal Perform high-pass filtering to obtain the high-frequency voltage signal output by the TMR current sensor at time t .

4. The digital output current measurement method based on TMR array according to claim 1, characterized in that: Under the triggering of the sampling clock, the low-frequency voltage signal and the high-frequency voltage signal are converted into analog-to-digital signals to obtain the converted low-frequency discrete voltage signal and high-frequency discrete voltage signal, and the power frequency current signal and the high-frequency current signal measured by the TMR current sensor are obtained after Fourier transformation, including: The synchronous clock unit is used to output a single-channel second pulse signal F1. When F1 rises, the first 24-bit analog-to-digital conversion chip is triggered to convert the low-frequency voltage signal Trigger sampling to obtain the corresponding low-frequency discrete voltage signal , and The relationship between them is as follows: ， ， In the formula, is the sampling rate of the first 24-bit analog-to-digital conversion chip; is the sampling point number of the low-frequency voltage signal, is the total number of sampling points of the low-frequency voltage signal; For the low frequency discrete voltage signal Perform Fourier transform to calculate low-frequency discrete voltage signal The corresponding power frequency component is used as the power frequency voltage signal , as shown below: ， In the formula, is the peak value of the power frequency voltage output by the TMR current sensor at time t, is the initial phase of the power frequency voltage output by the TMR current sensor at time t; According to the power frequency voltage signal , calculate the power frequency current signal of the measured line , as shown below: ， In the formula, is the peak value of the line power frequency current measured by the TMR current sensor at time t, is the initial phase of the line power frequency current measured by the TMR current sensor at time t; The synchronous clock unit outputs the second pulse signal F2, and the rising edge of F2 triggers the second 24-bit analog-to-digital conversion chip to convert the high-frequency voltage signal Perform trigger sampling to obtain the corresponding high-frequency discrete voltage signal , and The relationship between them is as follows: ， ， is the sampling rate of the second 24-bit analog-to-digital conversion chip; is the sampling point number of the high-frequency voltage signal, is the total number of sampling points of the high-frequency voltage signal; Based on high frequency discrete voltage signal Perform Fourier transform to calculate high-frequency discrete voltage signals The corresponding high-frequency voltage signal , as shown below: ， In the formula, is the harmonic order of the high-frequency voltage signal, is the output of TMR at time t The peak value of the sub-high frequency harmonic voltage, is the output of the TMR current sensor at time t The initial phase of the subharmonic voltage; According to the high frequency voltage signal Calculate the high-frequency current signal of the measured line as shown in the following formula: ， In the formula, It is the proportional coefficient of the TMR current sensor after calibration when the measured wire has no deflection angle, no eccentricity, and no external electromagnetic interference before leaving the factory. is the initial phase of the line nH subharmonic current measured by the TMR current sensor at time t.

5. The digital output current measurement method based on TMR array according to claim 4, characterized in that: Analyze and obtain the delay error sampling time caused by the asynchrony between the analog-to-digital conversion sampling clock signal and the trigger signal After that, it also includes: Sampling time based on delay error , calculate the phase deviation , as shown below: , where ( ) is the angular unit of minutes, and f is the frequency of the measured AC signal.

6. The digital output current measurement method based on TMR array according to claim 5, characterized in that: According to the low-frequency discrete voltage signal and the high-frequency discrete voltage signal after analog-to-digital conversion, a microprocessor is used to perform digital signal microprocessing, and the microprocessor microprocessing time of the low-frequency discrete voltage signal and the high-frequency discrete voltage signal is obtained through clock sampling. After that, it also includes: Based on microprocessing time , calculate the calibration value of the phase difference , as shown below: , ( ) is the angular unit of minutes.

7. The digital output current measurement method based on TMR array according to claim 6, characterized in that: According to the pre-sampling time of analog-to-digital conversion and the microprocessor's microprocessing time The phase error caused by the correction includes: Based on the power frequency voltage signal and the high frequency voltage signal , the sampling time of the delay error after the digital-to-analog conversion The phase deviation caused The correction is calculated as follows: ， In the formula, Indicates the phase deviation The corrected power frequency voltage signal, Indicates the phase deviation Corrected high frequency voltage signal; Microprocessor error time for digital signal The phase deviation caused The correction is calculated as follows: ， In the formula, Indicates the calibrated value of the phase difference The corrected power frequency voltage signal, Indicates the calibrated value of the phase difference Corrected high frequency voltage signal; Calculate the corrected power frequency current signal of the measured line and high frequency current signals for: 。 8. The digital output current measurement method based on TMR array according to claim 1, characterized in that: The corrected measurement data is encoded to obtain the corresponding digital output current, including: The corrected power frequency current signal is used as the measured value of the power frequency current signal of the line, and the corrected high frequency current signal is used as the measured value of the high frequency current signal of the line to obtain a digital output current.

9. The digital output current measurement method based on TMR array according to claim 8, characterized in that: Determine the encoding format of the digital output current signal, including: OXAA, OXFF, OXDA11, OXDA12, OXDA13, OXFA11, OXFA12, OXFA13, OXDA21, OXDA22, OXFA21, OXFA22, OXDA31, OXDA32, OXFA31, OXFA32, ..., OXDA601, OXDA602, OXFA601, OXFA602, OXAA, OX55; wherein, OX represents hexadecimal, OXAA, OXFF are frame headers, OXDAi1, OXDAi2, OXDAi3 are the measured values ​​of the line power frequency current signal, OXFAi1, OXFAi2, OXFAi3 are the measured values ​​of the line high frequency current signal, i=1,...,60, OXAA, OX55 are frame tails.

10. A digital output current measurement system based on a TMR array, characterized in that: For executing the method according to any one of claims 1 to 9, the system comprises: The TMR rectangular array includes four groups of TMR chips, and is used to obtain a secondary analog voltage signal of the measured circuit at time t that is proportional to the primary measured current signal; The analog signal processing module is used to perform low-pass analog filtering and high-pass analog filtering on the two outputs of the TMR current sensor in parallel based on the output signal of the TMR rectangular array, and obtain the low-frequency voltage signal and high-frequency voltage signal output by the TMR current sensor at time t; The synchronous clock generation module is used to output two synchronous second pulse signals to trigger two 24-bit analog-to-digital converters to digitally convert analog voltage signals; The analog-to-digital conversion module is composed of two 24-bit analog-to-digital converters. The two 24-bit analog-to-digital converters are used to perform analog-to-digital conversion on low-frequency voltage signals and high-frequency voltage signals under the triggering of a sampling clock to obtain corresponding low-frequency discrete voltage signals and high-frequency discrete voltage signals; The clock timing module uses TDC conversion technology to obtain the delay error sampling time caused by the asynchronization between the analog-to-digital conversion sampling clock signal and the trigger signal. and the microprocessing time of digital signal microprocessor ; A digital signal microprocessing module is used to sample the time according to the delay error. and the microprocessing time The phase error caused is corrected to obtain a corrected power frequency current signal and a corrected high frequency current signal as corrected measurement data; the corrected measurement data is encoded to obtain a corresponding digital output current.

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