Iron core type current sensor error measurement method and system

Abstract

The invention discloses an iron core type current sensor error measurement method and system, and the method comprises the steps: generating an excitation signal of a preset target magnetic field intensity peak value through a signal generator, amplifying the excitation signal through a power amplifier, and outputting the amplified excitation signal to an excitation winding of a detected current sensor, obtaining excitation impedance Zm of the detected current sensor; a compensation coil and a secondary side coil are wound on the detected current sensor, a secondary side loop is generated, and the total impedance Z20'of the secondary side loop of the detected current sensor is obtained; and calculating an error value of the detected current sensor based on the excitation impedance Zm and the total impedance Z20'of the secondary side loop.

Description

Technical Field

[0001] The present invention relates to the technical field of error measurement of electric energy metering devices, and more specifically, to an error measurement method and system for an iron core type current sensor. Background Art

[0002] As an important equipment for electricity trade settlement, the stability of the metering performance of electric energy metering instruments is of vital importance. In order to ensure the accuracy of electric energy metering under various conditions of the power system, electric energy metering instruments need to undergo complete performance tests before being put into use, including the error calibration of the sensor to ensure its metering performance after commissioning.

[0003] Before commissioning, the traditional core-type current sensor error measurement test relies on high-precision standards and error measurement units, which have high requirements for the accuracy of the measurement circuit; at the same time, this method has a complex circuit structure, cumbersome connection of the current sensor, and low measurement efficiency. In the case that some high-precision special core-type current sensor standards are difficult to develop, traditional error measurement tests cannot even be carried out.

[0004] Therefore, it is necessary to invent a method for measuring the error of any type of iron core current sensor, effectively measure the error of the iron core current sensor before commissioning, and ensure its reliable metering performance before grid operation. Summary of the invention

[0005] The technical solution of the present invention provides a method and system for measuring the error of an iron core current sensor, so as to solve the problem of how to measure the error of the iron core current sensor.

[0006] In order to solve the above problem, the present invention provides an error measurement method of an iron core current sensor, the method comprising:

[0007] The signal generator generates an excitation signal with a preset target magnetic field intensity peak value, and the excitation signal is amplified by a power amplifier and output to the excitation winding of the current sensor under test to obtain the excitation impedance Z of the current sensor under test. m ;

[0008] The measured current sensor is wound with a compensation coil and a secondary coil to generate a secondary loop, and the total impedance Z of the secondary loop of the measured current sensor is obtained. 20 ';

[0009] Based on the excitation impedance Z m And the total impedance Z of the secondary side circuit 20 ', calculate the error value of the measured current sensor.

[0010] Preferably, the excitation impedance Z of the current sensor to be measured is obtained m ,include:

[0011] Z m =2πjfL m +R m (1)

[0012] Among them, L m , R m are the equivalent inductance and equivalent resistance components of the excitation impedance respectively; j is an imaginary unit;

[0013] Excitation impedance Z of the current sensor being measured m According to the magnetic permeability of the core of the current sensor being measured As well as the core cross-sectional area S, the length of the magnetic path inside the core l is obtained according to the law of electromagnetic induction:

[0014]

[0015] Return the equivalent circuit to the primary side, N 1 is the number of turns of the primary winding; φ is the magnetic flux of the sensor core cross section, and e is the excitation voltage;

[0016] The magnetic flux of the core cross section is:

[0017] φ=N 1 BS (3)

[0018] Ampere's circuit law Hl = N 1 I 0 , where H is the magnetic field strength of the sensor core, and the magnetic induction intensity of the sensor core Substitute the core cross-section magnetic flux formula into:

[0019]

[0020] Substitute the core cross-section flux formula into the excitation voltage formula:

[0021]

[0022] The excitation voltage generated by the excitation current is expressed by the excitation impedance:

[0023] -e=Z m I 0 (6)

[0024] Combining equations (5) and (6), we get:

[0025]

[0026] Will Substituting into equation (7), we get the excitation impedance Z m Expression (8), where the number of primary turns N 1=1, the real part of the result of formula (8) corresponds to R in formula (1) m , the imaginary part corresponds to 2πfL in equation (1) m ;

[0027]

[0028] Preferably, the total impedance Z of the secondary side loop of the current sensor under test is obtained. 20 ',include:

[0029]

[0030] Among them, U L is the voltage across the secondary winding, I L is the current across the secondary winding.

[0031] Preferably, the excitation impedance Z m And the total impedance Z of the secondary side circuit 20 ', calculating the error value of the measured current sensor, including:

[0032] According to the corresponding relationship between the excitation current and the excitation impedance, the secondary winding current converted to the primary side is calculated according to formula (10):

[0033]

[0034] The total current of the working current range of the current sensor being measured is I 1 The calculation is as follows:

[0035] I 1 =I 0 +I′ 2 (11)

[0036] The composite error formula of the current sensor is as follows:

[0037]

[0038] Among them, I 0 is the excitation coil current, I 1 is the primary current, N 1 is the number of turns of the primary winding, I′ 2 is the secondary winding current, Z m is the magnetizing impedance.

[0039] According to another aspect of the present invention, the present invention provides an error measurement device for an iron core current sensor, the device comprising:

[0040] A signal generator, used to generate an excitation signal with a preset target magnetic field intensity peak value;

[0041] A power amplifier, used for amplifying the excitation signal and outputting it to the excitation winding of the current sensor to be measured;

[0042] Signal acquisition system, used to obtain the excitation impedance Z of the current sensor under test m , the current sensor under test is wound with a compensation coil and a secondary coil to generate a secondary loop, and the total impedance Z of the secondary loop of the current sensor under test is obtained 20 '; Based on the excitation impedance Z m And the total impedance Z of the secondary side circuit 20 ', calculate the error value of the measured current sensor.

[0043] Preferably, the signal acquisition system is used to obtain the excitation impedance Z of the current sensor being measured. m , also used for:

[0044] Z m =2πjfL m +R m (1)

[0045] Among them, L m , R m are the equivalent inductance and equivalent resistance components of the excitation impedance respectively; j is an imaginary unit;

[0046] Excitation impedance Z of the current sensor being measured m According to the magnetic permeability of the core of the current sensor being measured As well as the core cross-sectional area S, the length of the magnetic path inside the core l is obtained according to the law of electromagnetic induction:

[0047]

[0048] Return the equivalent circuit to the primary side, N 1 is the number of turns of the primary winding; φ is the magnetic flux of the sensor core cross section, and e is the excitation voltage;

[0049] The magnetic flux of the core cross section is:

[0050] φ=N 1 BS (3)

[0051] Ampere's circuit law Hl = N 1 I 0 , where H is the magnetic field strength of the sensor core, and the magnetic induction intensity of the sensor core Substitute the core cross-section magnetic flux formula into:

[0052]

[0053] Substitute the core cross-section flux formula into the excitation voltage formula:

[0054]

[0055] The excitation voltage generated by the excitation current is expressed by the excitation impedance:

[0056] -e=Z m I 0 (6)

[0057] Combining equations (5) and (6), we get:

[0058]

[0059] Will Substituting into equation (7), we get the excitation impedance Z m Expression (8), where the number of primary turns N 1 =1, the real part of the result of formula (8) corresponds to R in formula (1) m , the imaginary part corresponds to 2πfL in equation (1) m ;

[0060] .

[0062] Preferably, the signal acquisition system is used to obtain the total impedance Z of the secondary side loop of the current sensor under test. 20 ',include:

[0063]

[0064] Among them, U L is the voltage across the secondary winding, I L is the current across the secondary winding.

[0065] Preferably, the signal acquisition system is used to m And the total impedance Z of the secondary side circuit 20 ', calculating the error value of the measured current sensor, including:

[0066] According to the corresponding relationship between the excitation current and the excitation impedance, the secondary winding current converted to the primary side is calculated according to formula (10):

[0067]

[0068] The total current of the working current range of the current sensor being measured is I 1 The calculation is as follows:

[0069] I 1 =I 0 +I′ 2 (11)

[0070] The composite error formula of the current sensor is as follows:

[0071]

[0072] Among them, I 0 is the excitation coil current, I 1 is the primary current, N 1 is the number of turns of the primary winding, I′ 2 is the secondary winding current, Z m is the magnetizing impedance.

[0073] Based on another aspect of the present invention, the present invention provides a computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program, and the computer program is used to execute a method for measuring an error of an iron core current sensor.

[0074] Based on another aspect of the present invention, the present invention provides an electronic device, characterized in that the electronic device comprises: a processor and a memory; wherein,

[0075] The memory is a memory for storing instructions executable by the processor;

[0076] The processor is used to read the executable instructions from the memory and execute the instructions to implement an error measurement method for an iron core current sensor.

[0077] The technical solution of the present invention provides a method and device for measuring the error of an iron core current sensor, wherein the method comprises: generating an excitation signal with a preset target magnetic field intensity peak value through a signal generator, amplifying the excitation signal through a power amplifier and outputting it to the excitation winding of the current sensor to be measured, and obtaining the excitation impedance Z of the current sensor to be measured. m ; Wind the measured current sensor with a compensation coil and a secondary coil to generate a secondary loop, and obtain the total impedance Z of the secondary loop of the measured current sensor 20 '; Based on the excitation impedance Z m And the total impedance Z of the secondary side circuit 20 ', calculate the error value of the measured current sensor. The technical solution of the present invention proposes a method for calculating the sensor excitation impedance based on the core magnetic permeability and a method for accurately measuring the secondary winding impedance, which realizes the accurate calculation of the error from the perspective of the sensor equivalent circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0079] Figure 1 A flow chart of an error measurement method for an iron core current sensor according to a preferred embodiment of the present invention;

[0080] Figure 2 A schematic diagram of a T-type equivalent circuit of a current sensor according to a preferred embodiment of the present invention;

[0081] Figure 3 This is a flowchart of error calculation of an iron core current sensor according to a preferred embodiment of the present invention;

[0082] Figure 4 A specific working flow chart of the core type error measurement system according to a preferred embodiment of the present invention;

[0083] Figure 5 1 is a structural diagram of a magnetic property measuring device for an iron core type current sensor according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0084] Now, exemplary embodiments of the present invention are described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0085] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0086] Figure 1 The figure is a flow chart of an error measurement method of an iron core current sensor according to a preferred embodiment of the present invention.

[0087] The present invention proposes an error measurement method and system for an iron-core current sensor from the perspective of analyzing the equivalent circuit parameters of the iron-core sensor. Based on the acquisition of the excitation impedance of the iron-core current sensor and taking into account the secondary side load impedance, an error measurement method suitable for various types of iron-core current sensors is formed. The error of the current sensor is measured conveniently and efficiently, and the problem of the difficulty in developing high-precision standards for traditional measurement methods is avoided in a targeted manner, solving the problem of cumbersome connection of calibration equipment and low test efficiency is solved.

[0088] like Figure 1 As shown, the present invention provides an error measurement method for an iron core current sensor, the method comprising:

[0089] The signal generator generates an excitation signal with a preset target magnetic field intensity peak value, and the excitation signal is amplified by the power amplifier and output to the excitation winding of the current sensor under test to obtain the excitation impedance Z of the current sensor under test. m ;

[0090] Preferably, the excitation impedance Z of the current sensor to be measured is obtained m ,include:

[0091] Z m =2πjfL m +R m (1)

[0092] Among them, L m , R m are the equivalent inductance and equivalent resistance components of the excitation impedance respectively; j is an imaginary unit;

[0093] Excitation impedance Z of the current sensor being measured m According to the magnetic permeability of the core of the current sensor being measured As well as the core cross-sectional area S, the length of the magnetic path inside the core l is obtained according to the law of electromagnetic induction:

[0094]

[0095] Return the equivalent circuit to the primary side, N 1 is the number of turns of the primary winding; φ is the magnetic flux of the sensor core cross section, and e is the excitation voltage;

[0096] The magnetic flux of the core cross section is:

[0097] φ=N 1 BS (3)

[0098] Ampere's circuit law Hl = N 1 I 0 , where H is the magnetic field strength of the sensor core, and the magnetic induction intensity of the sensor core Substitute the core cross-section magnetic flux formula into:

[0099]

[0100] Substitute the core cross-section flux formula into the excitation voltage formula:

[0101]

[0102] The excitation voltage generated by the excitation current is expressed by the excitation impedance:

[0103] -e=Z m I 0 (6)

[0104] Combining equations (5) and (6), we get:

[0105]

[0106] Will Substituting into equation (7), we get the excitation impedance Z m Expression (8), where the number of primary turns N 1 =1, the real part of the result of formula (8) corresponds to R in formula (1) m , the imaginary part corresponds to 2πfL in equation (1) m ;

[0107]

[0108] The invention measures the magnetic permeability of the iron core of the iron core type current sensor and calculates the excitation impedance parameter of the iron core.

[0109] The calculation method of the core excitation impedance is as follows:

[0110] The excitation current in the core current sensor is the root cause of the error. The T-type equivalent circuit diagram of the current sensor is as follows: Figure 2 shown.

[0111] I 1 is the primary current, N 1 is the number of turns of the primary winding; I 0 is the excitation current, Z m is the excitation impedance; Z 20 ' is the total impedance of the secondary circuit referred to the primary side.

[0112] Z m =2πjfL m +R m , L m , R m are the equivalent inductance and equivalent resistance components of the excitation impedance respectively; Z 20 '=Z 2 '+Z', where the secondary winding impedance Z referred to the primary side 2 '=R 2 '+2πjfL 2 ', calculated to the primary side load impedance Z'=R'+2πjfL'.

[0113] Total impedance of secondary circuit Z 20 ' is formula (1):

[0114] Z 20 '=R 2 '+2πjfL 2 '+R'+2πjfL' (1)

[0115] Low voltage current sensor excitation impedance Z mAccording to the magnetic permeability of the sensor core As well as the core cross-sectional area S and the core internal magnetic path length l are obtained. The specific calculation process is as follows.

[0116] From the law of electromagnetic induction we know that:

[0117]

[0118] The equivalent circuit is calculated to the primary side, N 1 is the number of turns of the primary winding; φ is the magnetic flux of the sensor core, and e is the excitation voltage.

[0119] The magnetic flux of the core cross section is given by formula (3):

[0120] φ=N 1 BS (3)

[0121] Ampere's circuit law Hl = N 1 I 0 , where H is the magnetic field strength of the sensor core, and the magnetic induction intensity of the sensor core Substituting into the above formula, we get formula (4).

[0122]

[0123] Substituting formula (4) into formula (2) yields:

[0124]

[0125] At the same time, the excitation voltage generated by the excitation current can be expressed by the excitation impedance, that is:

[0126] -e=Z m I 0 (6)

[0127] Combining equations (5) and (6), we get:

[0128]

[0129] Will Wearable (7)

[0130] Get the excitation impedance Z m Expression (8), where the number of primary turns N 1 =1.

[0131]

[0132] pass Figure 5 The circuit shown measures the magnetic characteristics of the current sensor The system consists of a signal generator, a power amplifier, a current and voltage meter, a high-precision shunt, an oscilloscope, and the sensor core to be tested. The induction winding and the excitation winding are evenly wound on both sides of the annular core material; the signal generator is connected in series with the power amplifier, and the output end of the power amplifier is connected to the excitation winding. The excitation winding is connected to the acquisition system through a precision shunt device. The acquisition system obtains a precise voltage signal driven by the excitation current, thereby obtaining an excitation current signal, and the ammeter monitors the current value of the excitation winding in real time; the induction winding is connected in parallel to the acquisition system, thereby obtaining an induced voltage signal, and the voltmeter detects the real-time signal of the induced voltage. The signal generator is used to generate an excitation power supply control signal to achieve sinusoidal control of the current waveform at different frequencies and set the peak value of the magnetic field strength. The excitation signal is amplified by the power amplifier, and its output end is connected to the excitation winding. The target excitation current is obtained by adjusting the excitation power supply, so that the magnetic field strength inside the core reaches the target value. The measurement and display unit generally includes electrical measurement devices such as an effective value voltmeter V, an ammeter A, a precision shunt, and an oscilloscope. The test system measurement display unit is connected to the induction winding. The output end of the induction winding is open circuit and there is no current. Therefore, the magnetic field in the iron core is generated by the excitation coil current, and the excitation coil current is the excitation current. During the test, the test data is collected through the signal acquisition system, and the measured data is the excitation coil current I 0 And the induced voltage e at the output end of the induction winding.

[0133] Wind the current sensor under test with a compensation coil and a secondary coil to generate a secondary loop, and obtain the total impedance Z of the secondary loop of the current sensor under test. 20 ';

[0134] Preferably, the total impedance Z of the secondary side loop of the current sensor under test is obtained 20 ',include:

[0135]

[0136] Among them, U L is the voltage across the secondary winding, I L is the current across the secondary winding.

[0137] The present invention measures the impedance parameters of the secondary winding of the sensor and calculates the secondary side impedance parameters.

[0138] The method for measuring the secondary winding impedance of the present invention is as follows:

[0139] The secondary winding impedance measurement circuit is to wind an additional winding with the same number of turns as the secondary winding and opposite winding direction on the current sensor core, and connect the additional winding in series with the sensor secondary winding to ensure that the two windings generate reverse magnetic fields in the sensor core, where the ammeter measures the coil current and the voltmeter measures the voltage across the secondary winding. Since the magnetic fields generated by the two windings cancel each other out, the excitation current in the two windings is zero. The sensor secondary winding impedance can be calculated using the formula.

[0140]

[0141] Among them U L is the voltage across the secondary winding, I L is the current across the secondary winding.

[0142] Based on the excitation impedance Z m And the total impedance of the secondary circuit Z 20 ', calculate the error value of the current sensor under test.

[0143] The present invention determines the excitation current corresponding to the working primary current of the sensor and calculates the sensor error within the primary current range.

[0144] The present invention determines the quality of the sensor's measurement performance according to the sensor's accuracy level and in comparison with relevant standard requirements.

[0145] Preferably, based on the excitation impedance Z m And the total impedance of the secondary circuit Z 20 ', calculate the error value of the measured current sensor, including:

[0146] According to the corresponding relationship between the excitation current and the excitation impedance, the secondary winding current converted to the primary side is calculated according to formula (10):

[0147]

[0148] The total current of the working current range of the current sensor being measured is I 1 The calculation is as follows:

[0149] I 1 =I 0 +I′ 2 (11)

[0150] The composite error formula of the current sensor is as follows:

[0151]

[0152] Among them, I 0 is the excitation coil current, I 1 is the primary current, N 1 is the number of turns of the primary winding, I′ 2 is the secondary winding current, Z m is the magnetizing impedance.

[0153] The error calculation method of the present invention is as follows:

[0154] First, according to the corresponding relationship between the excitation current and the excitation impedance, the secondary winding current converted to the primary side is calculated according to formula (10).

[0155]

[0156] Total current I 1 As formula (11), the total current value is the working current range of the current sensor.

[0157] I 1 =I 0 +I′ 2 (11)

[0158] The composite error formula of the current sensor is as follows:

[0159]

[0160] The present invention measures the data Z m , Z 20 Substituting into formula (12) we can get the corresponding error under each range.

[0161] The present invention compares the relevant provisions of the standards of various countries, enterprises, etc. related to various current sensors to determine whether the sensor error is out of tolerance, and the sensor is qualified if the error does not exceed the limit value.

[0162] The present invention builds a magnetic measurement and impedance measurement system, combines precision measurement with theoretical calculation, and innovatively proposes a core current sensor error measurement method and device; combined with the essential cause of the error of the core current sensor, considering the influence of the core excitation impedance on the error result, it can effectively measure the errors of different types of core current sensors; a sensor excitation impedance calculation method based on the core magnetic permeability and a method for accurately measuring the secondary winding impedance are proposed, and accurate calculation of errors is achieved from the perspective of the sensor equivalent circuit. The method proposed by the present invention is helpful to carry out large-scale and efficient error verification of core current sensors before commissioning, and accurately judge their metering performance before commissioning.

[0163] like Figure 3 As shown, the present invention proposes a method for calculating the error of an iron core current sensor, which is now described by taking the error calculation of a low-voltage current sensor with an accuracy of 0.2 and a transformation ratio of 200 / 5 as an example:

[0164] Step 1: Connect the iron core low voltage current sensor Figure 5 The device shown measures the magnetic permeability at a magnetic induction intensity of 0T-1.5T Substituting the measured value of magnetic permeability into equation (8), we can obtain the excitation impedance Z of this current sensor: m

[0165] Step 2: Wind 40 turns of additional coil around the current sensor, connect the additional coil to the secondary winding, and measure the secondary winding impedance Z' 2 , during the application of the magnetic sensor, Z'=0.2Ω, and the total impedance of the secondary circuit is Z 20 '.

[0166] Step 3: Calculate the error value of the current sensor according to formula (12);

[0167] Step 4: Refer to the accuracy requirements for Class 0.2 low-voltage current sensors in JJG 1189.3-2022 "Measuring Transformers Part 3: Power Current Transformers" to determine the sensor's metering performance.

[0168] The present invention realizes accurate and convenient error calculation of the low-voltage current sensor, and can ensure that the metering performance of the core-type current sensor meets the requirements of relevant regulations before it is put into operation.

[0169] The magnetic property measurement system of the iron core current sensor of the present invention inputs the excitation current and measures the induced voltage, thereby obtaining the magnetic property (magnetic permeability) of the sensor;

[0170] The sensor secondary winding impedance measurement system is based on the principle that the reverse currents of the two windings will generate reverse magnetic fluxes inside the iron core to cancel each other out, effectively eliminating the problem of being unable to measure the secondary winding impedance due to the presence of excitation current during the measurement process;

[0171] The sensor equivalent circuit parameter and error calculation module effectively calculates the equivalent circuit parameters of the sensor at each primary current value according to the theoretical method proposed by the present invention, and calculates the error corresponding to the primary current value according to the equivalent circuit parameters.

[0172] The measurement performance identification module compares the error result obtained by the error calculation module with the error limit value specified in the corresponding sensor standard, and gives a conclusion on whether the error exceeds the allowable error. Figure 4 shown.

[0173] Figure 5 1 is a structural diagram of a magnetic property measuring device for an iron core type current sensor according to a preferred embodiment of the present invention.

[0174] The present invention provides an iron core type current sensor error measurement device, the device comprising:

[0175] A signal generator, used to generate an excitation signal with a preset target magnetic field intensity peak value;

[0176] A power amplifier, used for amplifying the excitation signal and outputting it to the excitation winding of the current sensor to be measured;

[0177] Signal acquisition system, used to obtain the excitation impedance Z of the current sensor under test m, wind the measured current sensor with compensation coil and secondary coil to generate the secondary loop, and obtain the total impedance Z of the secondary loop of the measured current sensor 20 '; Based on the excitation impedance Z m And the total impedance of the secondary circuit Z 20 ', calculate the error value of the current sensor under test.

[0178] Preferably, the signal acquisition system is used to obtain the excitation impedance Z of the current sensor under test m , also used for:

[0179] Z m =2πjfL m +R m (1)

[0180] Among them, L m , R m are the equivalent inductance and equivalent resistance components of the excitation impedance respectively; j is an imaginary unit;

[0181] Excitation impedance Z of the current sensor being measured m According to the magnetic permeability of the core of the current sensor being measured As well as the core cross-sectional area S, the length of the magnetic path inside the core l is obtained according to the law of electromagnetic induction:

[0182]

[0183] Return the equivalent circuit to the primary side, N 1 is the number of turns of the primary winding; φ is the magnetic flux of the sensor core cross section, and e is the excitation voltage;

[0184] The magnetic flux of the core cross section is:

[0185] φ=N 1 BS (3)

[0186] Ampere's circuit law Hl = N 1 I 0 , where H is the magnetic field strength of the sensor core, and the magnetic induction intensity of the sensor core Substitute the core cross-section magnetic flux formula into:

[0187]

[0188] Substitute the core cross-section flux formula into the excitation voltage formula:

[0189]

[0190] The excitation voltage generated by the excitation current is expressed by the excitation impedance:

[0191] -e=Z m I0 (6)

[0192] Combining equations (5) and (6), we get:

[0193]

[0194] Will Substituting into equation (7), we get the excitation impedance Z m Expression (8), where the number of primary turns N 1 =1, the real part of the result of formula (8) corresponds to R in formula (1) m , the imaginary part corresponds to 2πfL in equation (1) m ;

[0195]

[0196] Preferably, the signal acquisition system is used to obtain the total impedance Z of the secondary side loop of the current sensor under test. 20 ',include:

[0197]

[0198] Among them, U L is the voltage across the secondary winding, I L is the current across the secondary winding.

[0199] Preferably, the signal acquisition system is used based on the excitation impedance Z m And the total impedance of the secondary circuit Z 20 ', calculate the error value of the measured current sensor, including:

[0200] According to the corresponding relationship between the excitation current and the excitation impedance, the secondary winding current converted to the primary side is calculated according to formula (10):

[0201]

[0202] The total current of the working current range of the current sensor being measured is I 1 The calculation is as follows:

[0203] I 1 =I 0 +I′ 2 (11)

[0204] The composite error formula of the current sensor is as follows:

[0205]

[0206] Among them, I 0 is the excitation coil current, I 1 is the primary current, N 1is the number of turns of the primary winding, I′ 2 is the secondary winding current, Z m is the magnetizing impedance.

[0207] Based on another aspect of the present invention, the present invention provides a computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program, and the computer program is used to execute a method for measuring an error of an iron core current sensor.

[0208] Based on another aspect of the present invention, the present invention provides an electronic device, characterized in that the electronic device comprises: a processor and a memory; wherein,

[0209] Memory, a memory for storing processor executable instructions;

[0210] The processor is used for reading executable instructions from the memory and executing the instructions to implement an error measurement method of an iron core current sensor.

[0211] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes. The schemes in the embodiments of the present invention may be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0212] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0213] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0214] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0215] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0216] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0217] The invention has been described above with reference to a few embodiments. However, it is readily apparent to a person skilled in the art that other embodiments than the ones disclosed above are equally within the scope of the invention, as defined by the appended patent claims.

[0218] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a / said / the [means, components, etc.]" are to be openly interpreted as at least one instance of the means, components, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not necessarily have to be performed in the exact order disclosed, unless explicitly stated otherwise.

Claims

1. A method for measuring an error of an iron core current sensor, the method comprising: The signal generator generates an excitation signal with a preset target magnetic field intensity peak value, and the excitation signal is amplified by a power amplifier and output to the excitation winding of the current sensor under test to obtain the excitation impedance Z of the current sensor under test. m ; The measured current sensor is wound with a compensation coil and a secondary coil to generate a secondary loop, and the total impedance Z of the secondary loop of the measured current sensor is obtained. 20 '; Based on the excitation impedance Z m And the total impedance Z of the secondary side circuit 20 ', calculate the error value of the measured current sensor.

2. The method according to claim 1, wherein the excitation impedance Z of the current sensor under test is obtained. m ,include: Z m =2πjfL m +R m (1) Among them, L m , R m are the equivalent inductance and equivalent resistance components of the excitation impedance respectively; j is an imaginary unit; Excitation impedance Z of the current sensor being measured m According to the magnetic permeability of the core of the current sensor being measured As well as the core cross-sectional area S, the length of the magnetic path inside the core l is obtained according to the law of electromagnetic induction: The equivalent circuit is reduced to the primary side, N1 is the number of turns of the primary winding; φ is the magnetic flux of the sensor core cross section, and e is the excitation voltage; The magnetic flux of the core cross section is: φ=N1BS (3) The Ampere loop law Hl = N1I0, where H is the magnetic field strength of the sensor core, and the magnetic induction intensity of the sensor core Substitute the core cross-section magnetic flux formula into: Substitute the core cross-section flux formula into the excitation voltage formula: The excitation voltage generated by the excitation current is expressed by the excitation impedance: -e=Z m I0 (6) Combining equations (5) and (6), we get: Will Substituting into equation (7), we get the excitation impedance Z m Expression (8), where the number of primary turns N1 = 1, the real part of the result of equation (8) corresponds to R in equation (1) m , the imaginary part corresponds to 2πfL in equation (1) m ; 3. The method according to claim 1, wherein the total impedance Z of the secondary side loop of the current sensor under test is obtained. 20 ',include: Among them, U L is the voltage across the secondary winding, I L is the current across the secondary winding.

4. The method according to claim 1, wherein the excitation impedance Z m And the total impedance Z of the secondary side circuit 20 ', calculating the error value of the measured current sensor, including: According to the corresponding relationship between the excitation current and the excitation impedance, the secondary winding current converted to the primary side is calculated according to formula (10): The total current I1 of the working current range of the current sensor being measured is calculated as follows: I1=I0+I′2 (11) The composite error formula of the current sensor is as follows: Among them, I0 is the excitation coil current, I1 is the primary side current, N1 is the number of primary winding turns, I′2 is the secondary winding current, Z m is the magnetizing impedance.

5. A core current sensor error measurement device, the device comprising: A signal generator, used to generate an excitation signal with a preset target magnetic field intensity peak value; A power amplifier, used for amplifying the excitation signal and outputting it to the excitation winding of the current sensor to be measured; Signal acquisition system, used to obtain the excitation impedance Z of the current sensor under test m , the current sensor under test is wound with a compensation coil and a secondary coil to generate a secondary loop, and the total impedance Z of the secondary loop of the current sensor under test is obtained 20 '; Based on the excitation impedance Z m And the total impedance Z of the secondary side circuit 20 ', calculate the error value of the measured current sensor.

6. The device according to claim 5, wherein the signal acquisition system is used to obtain the excitation impedance Z of the current sensor under test m , also used for: Z m =2πjfL m +R m (1) in, L m , R m are the equivalent inductance and equivalent resistance components of the excitation impedance respectively; j is an imaginary unit; Excitation impedance Z of the current sensor being measured m According to the magnetic permeability of the core of the current sensor being measured As well as the core cross-sectional area S, the length of the magnetic path inside the core l is obtained according to the law of electromagnetic induction: The equivalent circuit is reduced to the primary side, N1 is the number of turns of the primary winding; φ is the magnetic flux of the sensor core cross section, and e is the excitation voltage; The magnetic flux of the core cross section is: φ=N1BS (3) The Ampere loop law Hl = N1I0, where H is the magnetic field strength of the sensor core, and the magnetic induction intensity of the sensor core Substitute the core cross-section magnetic flux formula into: Substitute the core cross-section flux formula into the excitation voltage formula: The excitation voltage generated by the excitation current is expressed by the excitation impedance: -e=Z m I0 (6) Combining equations (5) and (6), we get: Will Substituting into equation (7), we get the excitation impedance Z m Expression (8), where the number of primary turns N1 = 1, the real part of the result of equation (8) corresponds to R in equation (1) m , the imaginary part corresponds to 2πfL in equation (1) m ; 7. The device according to claim 5, wherein the signal acquisition system is used to obtain the total impedance Z of the secondary side loop of the current sensor under test. 20 ',include: Among them, U L is the voltage across the secondary winding, I L is the current across the secondary winding.

8. The device according to claim 5, wherein the signal acquisition system is used to m And the total impedance Z of the secondary side circuit 20 ', calculating the error value of the measured current sensor, including: According to the corresponding relationship between the excitation current and the excitation impedance, the secondary winding current converted to the primary side is calculated according to formula (10): The total current I1 of the working current range of the current sensor being measured is calculated as follows: I1=I0+I′2 (11) The composite error formula of the current sensor is as follows: Among them, I0 is the excitation coil current, I1 is the primary side current, N1 is the number of primary winding turns, I′2 is the secondary winding current, Z m is the magnetizing impedance.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and the computer program is used to execute the method according to any one of claims 1 to 4.

10. An electronic device, characterized in that: The electronic device comprises: a processor and a memory; wherein, The memory is a memory for storing instructions executable by the processor; The processor is configured to read the executable instructions from the memory and execute the instructions to implement the method according to any one of claims 1 to 4.

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