Current measurement error correction method, device and system of TMR current sensor

Abstract

The invention discloses a current measurement error correction method, device and system of a TMR current sensor, and belongs to the technical field of power systems. A correction coefficient function capable of accurately reflecting the influence characteristics of the temperature and the frequency on the amplitude of the current signal is constructed by performing nonlinear fitting on the relation between the correction coefficient and the temperature and the frequency, so that the error correction can be accurately performed based on the frequency of the current signal to be measured and the temperature of the environment where the TMR current sensor is located in the error correction process. And obtaining a current correction coefficient in real time for correction. The method is simple in calculation, does not need to introduce an additional modulation circuit, can improve the current measurement accuracy of the TMR current sensor in a simple mode, and is suitable for application scenes such as motor control, intelligent power grid monitoring and high-precision current detection.

Description

Technical Field

[0001] The present invention belongs to the technical field of power systems, and more specifically, relates to a method, device, and system for correcting current measurement errors of a TMR current sensor. Background Art

[0002] In recent years, with the construction of new power systems, power electronic technologies in transmission networks represented by ultra-high voltage direct current and flexible transmission have been widely applied. For example, a large number of large-scale intermittent new energy sources such as wind power and photovoltaic power have been connected to the grid, a large number of nonlinear loads and impact loads have been increasing continuously, and high-power power electronic devices have been widely used, all of which have brought new challenges and problems to traditional power systems. New characteristics and requirements have emerged in power quality problems, especially harmonic problems, in power systems. Therefore, it is required to comprehensively understand and control the power quality in power systems. Among various power quality problems, harmonics have a wide range of effects and a greater impact, and are important indicators that need to be detected in power quality.

[0003] Current sensors are indispensable devices in power systems, which are used to measure current and convert it into a standard signal for use in monitoring, control, and protection systems. With the progress of technology, tunnel magnetoresistance (TMR) current sensors have become the first choice for current measurement in new power systems due to their advantages such as low power consumption, high response frequency, and high sensitivity. However, in actual operation, current sensors will be affected by various environmental factors, which may cause measurement errors. Therefore, calibration is required to ensure their measurement accuracy and reliability.

[0004] Existing methods for correcting current measurement errors of TMR current sensors generally perform current measurement error correction by adding a corresponding modulation circuit at the rear end of the current sensor. The modulation circuit generally consists of a power supply, signal amplification, filtering circuit, bias zeroing circuit, temperature compensation circuit, power amplification circuit, feedback coil, etc., which increases the circuit complexity of the current sensor. At the same time, since changes in temperature and frequency can significantly affect the electrical performance of internal components of the current sensor, including changes in inductance and resistance values, and thus directly affect the output accuracy of the current sensor. Therefore, when calibrating the current sensor, temperature and frequency factors usually need to be considered. However, the modulation circuit is limited by component linearity, accuracy, tolerance, etc., and it is difficult to achieve nonlinear compensation. Moreover, when the temperature changes, the parameters of the modulation circuit will also drift, introducing new errors instead, and the accuracy is relatively low. Summary of the Invention

[0005] Aiming at the above defects or improvement requirements of the prior art, the present invention provides a method, device, and system for correcting current measurement errors of a TMR current sensor, aiming to improve the current measurement accuracy of the TMR current sensor in a relatively simple manner.

[0006] To achieve the above object, in a first aspect, the present invention provides a method for correcting the current measurement error of a TMR current sensor, including:

[0007] Substitute the frequency of the current signal to be measured and the ambient temperature of the TMR current sensor into the correction coefficient function to obtain the current correction coefficient;

[0008] Multiply the measured amplitude of the current signal of the TMR current sensor by the current correction coefficient to correct the measurement error of the current signal of the TMR current sensor;

[0009] Among them, the acquisition method of the correction coefficient function includes:

[0010] Obtain the measurement data of the amplitudes of the I-th harmonic current signals with N different specified amplitudes measured M times by the TMR current sensor at J different temperatures respectively; J≥2; N≥2; I≥1; M≥1;

[0011] Calculate the ratio of each specified amplitude of the i-th harmonic current signal at the j-th temperature to the corresponding M measured amplitudes, and average the obtained NM ratios as the correction coefficient of the i-th harmonic current signal at the j-th temperature; j = 1, 2,..., J; i = 1, 2,..., I;

[0012] Based on the obtained correction coefficients of different harmonic current signals at different temperatures, perform a non-linear fitting on the relationship between the correction coefficient and temperature and frequency to obtain the correction coefficient function; among them, the frequency of the i-th harmonic current signal is i times the fundamental frequency.

[0013] Further preferably, the non-linear fitting of the relationship between the correction coefficient and temperature and frequency includes:

[0014] Express the correction coefficient function as where a1, a2, b1, b2, k are fitting parameters; f and T represent frequency and temperature respectively;

[0015] Calculate the average value A of the M measured amplitudes corresponding to the n-th specified amplitude of the i-th harmonic current signal at the j-th temperature i,j,n , and multiply A i,j,n by C(f i , T j ) as the corrected current amplitude of the i-th harmonic current signal with the n-th specified amplitude at the j-th temperature; where f i is the frequency of the i-th harmonic current signal; T j is the j-th temperature;

[0016] Construct an objective function aiming to minimize the sum of the difference losses between the corrected current amplitudes of the I - th harmonic current signals with N different specified amplitudes at J different temperatures and the corresponding specified amplitudes, and solve for the fitting parameters in the correction coefficient function based on the objective function to obtain the correction coefficient function.

[0017] Further preferably, the above - mentioned objective function is:

[0018]

[0019] Wherein, is the corrected current amplitude of the I - th harmonic current signal with the n - th specified amplitude at the j - th temperature; A n is the n - th specified amplitude.

[0020] Further preferably, the value range of M is from 3 to 5 times.

[0021] In a second aspect, the present invention provides a current measurement error correction device, including: a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, it executes the current measurement error correction method provided in the first aspect of the present invention.

[0022] In a third aspect, the present invention provides a current measurement system, including: a TMR current sensor and the current measurement error correction device provided in the second aspect;

[0023] The current measurement error correction device is used to correct the current measurement error of the TMR current sensor.

[0024] In a fourth aspect, the present invention further provides a computer - readable storage medium, the computer - readable storage medium includes a stored computer program, wherein when the computer program is run by a processor, it controls the device where the storage medium is located to execute the current measurement error correction method provided in the first aspect of the present invention.

[0025] In a fifth aspect, the invention further provides a computer program product, including a computer program / instructions, and when the computer program / instructions are executed by a processor, they implement the current measurement error correction method provided in the first aspect of the present invention.

[0026] Generally speaking, through the above - mentioned technical solutions conceived by the present invention, the following beneficial effects can be achieved:

[0027] 1. The present invention provides a method for correcting the current measurement error of a TMR current sensor. By performing a non-linear fitting on the relationship between the correction coefficient and temperature and frequency, a correction coefficient function is constructed that can accurately reflect the influence characteristics of temperature and frequency on the amplitude of the current signal. Thus, during the error correction process, based on the frequency of the current signal to be measured and the ambient temperature of the TMR current sensor, the current correction coefficient can be obtained in real time for correction. The calculation of the present invention is simple, without the need to introduce an additional modulation circuit, and can improve the current measurement accuracy of the TMR current sensor in a relatively simple manner.

[0028] 2. In the current measurement error correction method provided by the present invention, when calculating the correction coefficient of a certain harmonic current signal at a certain temperature, by calculating the ratio of each specified amplitude of the harmonic current signal at that temperature to the corresponding M measured amplitudes respectively, and averaging the obtained NM ratios, as the correction coefficient of the harmonic current signal at that temperature, it can eliminate the random error in a single measurement or the instantaneous interference of the external environment, and improve the stability and reliability of the correction coefficient.

[0029] 3. Further, in the current measurement error correction method provided by the present invention, through the analysis of the correction coefficients at different temperatures and frequencies by the present invention, it is found that as the frequency increases, the correction coefficient gradually decreases and tends to be stable, and at a fixed frequency, the difference between the temperature curves is basically approximately fixed, showing a non-linear overall translation. Therefore, based on the above analysis, when performing a non-linear fitting on the relationship between the correction coefficient and temperature and frequency, the present invention first expresses the correction coefficient function as Then, a target function is constructed with the goal of minimizing the sum of the difference losses between the corrected current amplitudes and the corresponding specified amplitudes of the I-th harmonic current signals with N different specified amplitudes at J different temperatures, and the fitting parameters in the correction coefficient function are solved, which can more accurately characterize the relationship between the correction coefficient and temperature and frequency.

[0030] 4. Further, in the current measurement error correction method provided by the present invention, the preferred value range of M is 3 to 5 times to balance the calculation complexity and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a flowchart of a method for obtaining a correction coefficient function provided by an embodiment of the present invention;

[0032] Figure 2 It is a schematic structural diagram of the high-frequency impedance equivalent circuit of a Wheatstone bridge type TMR sensor provided by an embodiment of the present invention;

[0033] Figure 3 It is a graph showing the change of the correction coefficient with frequency at different temperatures provided by an embodiment of the present invention. Specific Embodiments

[0034] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] By studying the non-linear relationship between temperature and harmonic current signals and developing a temperature and frequency compensation algorithm for directly correcting current measurement signals, the measurement accuracy of the power system can be improved to ensure its stable operation. The practical application of temperature and frequency compensation technology requires a comprehensive evaluation to determine its effectiveness and feasibility in different power system environments. Only through in-depth research and verification can the effective application of temperature and frequency compensation technology in improving the performance and reliability of power systems be ensured. In-depth research in this field will help to promote the progress of power system technology to meet the growing energy demand while achieving the goal of environmental protection. Therefore, it is necessary to establish a non-linear relationship between temperature and frequency and harmonic signals and design an accurate temperature compensation algorithm that can directly correct measurement signals.

[0036] To achieve the above object, in a first aspect, the present invention provides a method for correcting the current measurement error of a TMR current sensor, including:

[0037] Substitute the frequency of the current signal to be measured and the ambient temperature of the TMR current sensor into the correction coefficient function to obtain the current correction coefficient;

[0038] Multiply the measured amplitude of the current signal of the TMR current sensor by the current correction coefficient to correct the current measurement error of the TMR current sensor;

[0039] Wherein, as Figure 1 shown, the method for obtaining the correction coefficient function includes:

[0040] Obtain measurement data of the TMR current sensor measuring the amplitudes of I-th harmonic current signals with N different specified amplitudes M times at J different temperatures; J≥2; N≥2; I≥1; M≥1; It should be noted that M can take the value of 1, but in order to further improve the accuracy, M is generally greater than or equal to 2 times. However, considering the computational complexity, preferably, the value range of M is 3 to 5 times;

[0041] Calculate the ratios of each specified amplitude of the i-th harmonic current signal at the j-th temperature to the corresponding M measured amplitudes, and average the obtained NM ratios as the correction coefficient of the i-th harmonic current signal at the j-th temperature; j = 1, 2, …, J; i = 1, 2, …, I;

[0042] Based on the obtained correction coefficients of different harmonic current signals at different temperatures, perform a non-linear fitting on the relationship between the correction coefficient, temperature, and frequency to obtain a correction coefficient function; wherein, the frequency of the i-th harmonic current signal is i times the fundamental frequency.

[0043] The present invention introduces a non-linear parametric function for the amplitude of the current signal, namely the correction coefficient function, which can more accurately reflect the influence characteristics of temperature and frequency on the amplitude of the current signal, thereby reducing the correction error and improving the calculation efficiency. This method deeply reveals the actual influence of temperature and frequency changes on the measurement of the harmonic signal amplitude by constructing a correction coefficient function for current signal amplitude correction, providing a way for accurate parametric evaluation. The present invention can solve the problem in the prior art that the changes in temperature and frequency significantly affect the electrical performance of the internal components of the TMR current sensor, including the changes in inductance and resistance values, thereby affecting the output accuracy of the TMR current sensor, and can improve the measurement accuracy and reliability of the TMR current sensor in a complex environment.

[0044] It should be noted that the non-linear fitting can adopt non-linear fittings such as logarithmic function fitting and polynomial fitting.

[0045] To achieve a more accurate fitting, the present invention analyzes the correction coefficients at different temperatures and frequencies and finds that at different temperatures, the change trend of the correction coefficient with frequency is similar, specifically manifested as: as the frequency increases, the correction coefficient gradually decreases and tends to be stable, and at a fixed frequency, the difference between the temperature curves is basically approximately fixed, showing a non-linear overall translation. Therefore, the present invention represents the relationship between the correction coefficient, frequency, and temperature as which can accurately characterize this trend. Preferably, in an alternative embodiment, the process of non-linearly fitting the relationship between the correction coefficient and temperature and frequency includes:

[0046] Represent the correction coefficient function as where a1, a2, b1, b2, k are fitting parameters; f and T represent frequency and temperature respectively;

[0047] Calculate the average value A of the M measured amplitudes corresponding to the n-th specified amplitude of the i-th harmonic current signal at the j-th temperature i,j,n , and take A i,j,n and compare it with C(f i , T j) Multiply them as the corrected current amplitude of the i-th harmonic current signal with the n-th specified amplitude at the j-th temperature;

[0048] Construct an objective function aiming to minimize the sum of the difference losses between the corrected current amplitudes of the I-th harmonic current signals with N different specified amplitudes at J different temperatures and the corresponding specified amplitudes, and solve for the fitting parameters in the correction coefficient function based on the objective function to obtain the correction coefficient function;

[0049] where, f i is the frequency of the i-th harmonic current signal; T j is the j-th temperature.

[0050] It should be noted that there are various ways to measure the difference loss, which can be measured by means such as mean absolute error, mean square error, root mean square error, etc., and are not limited here.

[0051] Preferably, in an alternative implementation manner, the least squares method is used to construct the above objective function, and the constructed objective function is:

[0052]

[0053] where, is the corrected current amplitude of the i-th harmonic current signal with the n-th specified amplitude at the j-th temperature; A n is the n-th specified amplitude.

[0054] It should be noted that there are various methods to solve the objective function, which can be methods such as gradient descent method, Newton method, etc., and are not limited here.

[0055] To further illustrate the current measurement error correction method provided by the present invention, the following will be described in detail with a specific embodiment:

[0056] This example takes a Wheatstone bridge type TMR current sensor as an example; among them, the high-frequency impedance equivalent circuit of the Wheatstone bridge type TMR sensor is as Figure 2 shown.

[0057] The current measurement error correction method in this embodiment mainly includes the following two parts:

[0058] 1) Construct the correction coefficient function, and the specific steps are as follows:

[0059] S1. Obtain the measurement data of the amplitudes of the I-th harmonic current signals with N different specified amplitudes measured M times by the TMR current sensor at J different temperatures respectively; J≥2; N≥2; I≥1; M≥1;

[0060] The measurement data in this embodiment is expressed as:

[0061]

[0062] Among them, I c(ij) is the measurement result of the i-th harmonic current signal at the j-th temperature; I c(ij) (1,1) to I c(ij) (M,N) are the measurement data of M measurements of the i-th harmonic current signal with N different specified amplitudes at the j-th temperature respectively; I c(ij) (m,n) is the measurement data of the m-th measurement of the i-th harmonic current signal with n different specified amplitudes at the j-th temperature; j = 1, 2, …, J; i = 1, 2, …, I; m = 1, 2, …, M; n = 1, 2, …, N. M is the number of measurements under the same conditions, N is the number of specified amplitudes, I is the number of harmonics, and J is the number of temperatures.

[0063] In this embodiment, at temperatures of -40°C, -20°C, 0°C, 20°C, 40°C, 60°C, and 80°C respectively, the TMR current sensor is used to collect the harmonic current signals with a sampling step of 100 Hz from 0 to 3000 Hz at specified amplitude parameters of 0.5 A, 1 A, and 2 A, and collect the amplitudes of the harmonic current signals for each specified amplitude twice, and record the amplitudes collected by the TMR current sensor.

[0064] In this embodiment, the TMR current sensor is placed in a variable temperature control test chamber to control and obtain the measurement ambient temperature.

[0065] S2. Calculate the ratio of each specified amplitude of the i-th harmonic current signal at the j-th temperature to the corresponding M measured amplitudes respectively, and average the obtained NM ratios as the correction coefficient of the i-th harmonic current signal at the j-th temperature; j = 1, 2, …, J; i = 1, 2, …, I;

[0066] Specifically, the ratio of the n-th specified amplitude of the i-th harmonic current signal at the j-th temperature to the m-th measured amplitude is used as the correction coefficient of the i-th harmonic current signal with the n-th specified amplitude at the j-th temperature, denoted as:

[0067]

[0068] Among them, A i,j,m,n is the measured amplitude of the i-th harmonic current signal with the n-th specified amplitude at the j-th temperature; A n is the n-th specified amplitude.

[0069] For the i-th harmonic current signal at the j-th temperature, a total of NM correction coefficients are obtained, and the average value of the NM correction coefficients is calculated as the correction coefficient of the i-th harmonic current signal at the j-th temperature. Taking the average eliminates the random error in a single measurement or the instantaneous interference of the external environment, thereby improving the stability and reliability of the correction coefficient.

[0070] In this embodiment, the calculation data of the correction coefficients of the I-th harmonic current signals at J temperatures are as described in Table 1.

[0071] Table 1

[0072]

[0073] S3. Based on the obtained correction coefficients of different harmonic current signals at different temperatures, perform a non-linear fitting on the relationship between the correction coefficient and temperature and frequency to obtain a correction coefficient function; where the frequency of the i-th harmonic current signal is i times the fundamental frequency.

[0074] Specifically, in this embodiment, according to the variation law of the correction coefficient, for the i-th harmonic signal under j temperature conditions, a non-linear parametric function for correcting the amplitude of the harmonic current signal is constructed, that is: a non-linear parametric function regarding the amplitude correction parameter (the functional relationship between the correction coefficient and frequency and the measurement ambient temperature). Based on the constructed non-linear parametric function, a correction model fitting error function and unknowns are solved, and the harmonic signal amplitude correction coefficient function is obtained through the data collected in step S1 and the data processed in step S2.

[0075] The obtained correction coefficient function after fitting is expressed as where a1, a2, b1, b2, and k are fitting parameters, all of which are parameters to be solved and are used to control the non-linear relationship between frequency, temperature, and the correction coefficient; f and T represent frequency and temperature respectively;

[0076] Calculate the average value A of the M measured amplitudes corresponding to the n-th specified amplitude of the i-th harmonic current signal at the j-th temperature i,j,n , and multiply A i,j,n by C(f i , T j ) as the corrected current amplitude of the i-th harmonic current signal at the n-th specified amplitude at the j-th temperature; where f i is the frequency of the i-th harmonic current signal; T j is the j-th temperature;

[0077] Construct an objective function aiming to minimize the sum of the difference losses between the corrected current amplitudes of the I - th harmonic current signals with N different specified amplitudes at J different temperatures and the corresponding specified amplitudes, and solve the fitting parameters in the correction coefficient function based on the objective function to obtain the correction coefficient function.

[0078] In this embodiment, based on the least - squares method, it is fitted that a1 = 64238.47, a2 = 1179245.23, b1 = - 572468.45, b2 = - 605934.70, k = 1. The fitted function curve is as Figure 3 shown.

[0079] 2) Current measurement error correction:

[0080] Obtain the measurement ambient temperature where the TMR current sensor is located. As an alternative implementation, in this embodiment, it is specified to correct the measurement error of the measurement result of the current signal to be measured with a frequency of 2500 Hz by using the TMR current sensor in an environment of 80°C. The current frequency of the signal to be measured is 2500 Hz, and the measurement ambient temperature is 80°C.

[0081] The specific steps of current measurement error correction include:

[0082] Substitute the frequency 2500 Hz of the current signal to be measured and the ambient temperature 80°C where the TMR current sensor is located into the correction coefficient function to obtain the current correction coefficient 0.99844;

[0083] Multiply the measured amplitude of the current signal of the TMR current sensor by the current correction coefficient to correct the measurement error of the current signal of the TMR current sensor, and take the measurement result of the current signal after amplitude correction as the final measurement result.

[0084] In this example, the specified amplitude data of the current signal output by the TMR current sensor collected is 5 A, and the corrected value is 4.9922 A.

[0085] In summary, this embodiment introduces a non-linear parametric function for the amplitude of harmonic current signals, namely the correction coefficient function, which can more accurately correct the influence of temperature and signal frequency. It is particularly suitable for the cases where the amplitudes of harmonic current signals and correction coefficients are different, reducing errors and improving calculation efficiency. By constructing a non-linear parametric function for the correction of the amplitude of harmonic current signals, this method deeply reveals the actual influence of temperature and signal frequency changes on the measurement of harmonic current signals, providing a way for accurate parametric evaluation. The method of this embodiment proposes a method for compensating the temperature and signal frequency of the amplitude measurement error of harmonic current signals in a power system to improve the accuracy of the measured signal. By deeply studying the relationship between temperature, signal frequency and the signal, it reveals the non-linear influence of temperature and signal frequency on the amplitude error of each harmonic measurement signal, and proposes a method for correcting the harmonic measurement error considering the amplitude error simultaneously, which can provide more accurate data for the measurement of harmonic current signals and contribute to improving the stability of the power system. Compared with the traditional non-parametric fitting method, the method of this embodiment is more suitable for the case of correcting the amplitude of harmonic current signals, reducing errors and having higher calculation efficiency at the same time. The parametric fitting method adopted in this embodiment shows more advantages in adapting to data characteristics, providing interpretability, prediction performance and generalization performance because it uses a clearly defined mathematical model, allowing less data to obtain good fitting results. By constructing a non-linear parametric function for the correction of the amplitude of harmonic current signals, this embodiment can better capture the non-linear variation characteristics of the amplitude, so as to more accurately correct the temperature and signal frequency. This embodiment can realize the test of the amplitude measurement error of harmonic current signals in a power system with temperature and signal frequency changes, solving the defect of low-precision measurement caused by existing measuring instruments and measurement methods ignoring the influence of temperature. Thus, it promotes the technical level of the harmonic current signal measurement industry, improves and perfects the harmonic measurement error evaluation and measurement accuracy, and has important economic and social benefits.

[0086] The present invention effectively improves the measurement accuracy of the TMR current sensor in a complex environment and is applicable to application scenarios such as motor control, smart grid monitoring, and high-precision current detection.

[0087] In a second aspect, the present invention provides a current measurement error correction device, including: a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, it executes the current measurement error correction method provided in the first aspect of the present invention.

[0088] The related technical solutions are the same as the current measurement error correction method provided in the first aspect of the present invention and will not be elaborated here.

[0089] In a third aspect, the present invention provides a current measurement system, including: a TMR current sensor and the current measurement error correction device provided in the second aspect;

[0090] The current measurement error correction device is used to correct the current measurement error of the TMR current sensor.

[0091] The related technical solutions are the same as those of the current measurement error correction device provided in the second aspect of the present invention, and will not be elaborated here.

[0092] In a fourth aspect, the present invention further provides a computer-readable storage medium, which includes a stored computer program. When the computer program is run by a processor, it controls the device where the storage medium is located to execute the current measurement error correction method provided in the first aspect of the present invention.

[0093] The related technical solutions are the same as those of the current measurement error correction method provided in the first aspect of the present invention, and will not be elaborated here.

[0094] In a fifth aspect, the invention further provides a computer program product, including a computer program / instructions. When the computer program / instructions are executed by a processor, the current measurement error correction method provided in the first aspect of the present invention is implemented.

[0095] The related technical solutions are the same as those of the current measurement error correction method provided in the first aspect of the present invention, and will not be elaborated here.

[0096] Those skilled in the art can easily understand that the above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for correcting current measurement error of a TMR current sensor, characterized in that, Including: Substitute the frequency of the current signal to be measured and the ambient temperature where the TMR current sensor is located into the correction coefficient function to obtain the current correction coefficient; Multiply the measured amplitude of the current signal of the TMR current sensor by the current correction coefficient to correct the measurement error of the current signal of the TMR current sensor; The acquisition method of the correction coefficient function includes: Obtain measurement data of the amplitudes of the I -th harmonic current signals with N different specified amplitudes measured M times by the TMR current sensor at J different temperatures respectively; J≥2; N≥2; I≥1; M≥1; Calculate the ratio of each specified amplitude of the i -th harmonic current signal at the j -th temperature to the corresponding M measured amplitudes, and average the obtained NM ratios as the correction coefficient of the i -th harmonic current signal at the j -th temperature; j = 1, 2, …, J; i = 1, 2, …, I; Based on the obtained correction coefficients of different harmonic current signals at different temperatures, perform non - linear fitting on the relationship between the correction coefficient and temperature and frequency to obtain the correction coefficient function; where the frequency of the i -th harmonic current signal is i times the fundamental frequency.

2. The current measurement error correction method according to claim 1, wherein The non - linear fitting of the relationship between the correction coefficient and temperature and frequency includes: Express the correction coefficient function as where a1, a2, b1, b2, and k are fitting parameters; f and T represent frequency and temperature respectively; Calculate the average value A of M measured amplitudes corresponding to the nth specified amplitude of the ith harmonic current signal at the jth temperature i,j,n , and multiply A i,j,n by C(f i , T j ) as the corrected current amplitude of the ith harmonic current signal with the nth specified amplitude at the jth temperature; where f i is the frequency of the ith harmonic current signal; T j is the jth temperature; Construct an objective function aiming to minimize the sum of the difference losses between the corrected current amplitudes and the corresponding specified amplitudes of the I -th harmonic current signals with N different specified amplitudes at J different temperatures, and solve the fitting parameters in the correction coefficient function based on the objective function to obtain the correction coefficient function.

3. The current measurement error correction method according to claim 2, wherein The objective function is: Among them, is the corrected current amplitude of the i-th harmonic current signal with the n-th specified amplitude at the j-th temperature; A n is the n-th specified amplitude.

4. The current measurement error correction method according to any one of claims 1-3, characterized in that The value range of M is 3 to 5 times.

5. A current measurement error correction device, characterized in that, Including: A memory and a processor, the memory stores a computer program, and when the processor executes the computer program, it executes the current measurement error correction method according to any one of claims 1 - 4.

6. A current measurement system, characterized in that, Including: A TMR current sensor and the current measurement error correction device according to claim 5; The current measurement error correction device is used to correct the current measurement error of the TMR current sensor.

7. A computer-readable storage medium, characterized in that, The computer - readable storage medium includes a stored computer program, wherein when the computer program is run by a processor, it controls the device where the storage medium is located to execute the current measurement error correction method according to any one of claims 1 - 4.

8. A computer program product, characterized in that, Including a computer program / instructions, when the computer program / instructions are executed by a processor, they implement the current measurement error correction method according to any one of claims 1 - 4.

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