A current coefficient measuring device and a measuring method

Abstract

The present invention provides a current coefficient measuring device and a measuring method. The device includes a first unit, a second unit, a third unit, a fourth unit and a fifth unit; the first unit includes a current source, a second current ratio standard, a third current ratio standard, a second standard current-voltage converter and a first voltage testing device; the second unit includes a current source, a fourth current ratio standard, a third standard current-voltage converter, a fourth standard current-voltage converter and a second voltage testing device; the third unit includes a current source, a third current ratio standard, a third standard current-voltage converter and a third voltage testing device; the fourth unit includes a current source, a third current ratio standard, a fourth standard current-voltage converter and a fourth voltage testing device. This solution greatly improves the accuracy of the measurement results. The standard current-voltage converter is only used for numerical transition to meet the requirements of precision measurement result correction.

Description

Technical Field

[0001] The present invention relates to the field of measurement technology, and in particular to a current coefficient measuring device and a measuring method. Background Art

[0002] High current measurement is an essential component of modern electromagnetic metrology, encompassing numerous areas of industrial production and scientific research. Examples include electricity metering in the power transmission and distribution industry and the electric vehicle industry, precision current measurement in nuclear magnetic resonance equipment in the medical industry, and high-performance current source monitoring in large scientific facilities such as particle colliders and synchrotron radiation sources. The principle of high current measurement primarily involves converting high current into a small voltage or current for easy measurement with general-purpose instruments. Representative devices include current-to-voltage converters (hereinafter referred to as "converters"), which calculate the measured current value by multiplying the voltage value by a conversion coefficient. Therefore, the accuracy of the conversion coefficient directly affects the measurement results.

[0003] Due to factors such as the material, structure, and design of the converter, the value of the conversion coefficient will change with the change of the current to be measured. Usually, the conversion coefficient at one-tenth of the upper limit of the converter's range is used as the starting point and reference point. The conversion coefficients within the remaining range are compared with the conversion coefficient at the starting point to obtain the current coefficient of the converter. In the field of precision measurement, for example, some large hadron collider particle accelerators need to supply a continuous and stable large current to the superconducting magnet. In order to achieve the predetermined goals of the project, the conversion coefficient of the converter used needs to be calibrated to better than 2×10 -6 It can be seen that the current coefficient cannot be ignored and should be accurately measured to correct the measurement results.

[0004] The measurement of the current coefficient needs to be obtained based on the conversion coefficient. For the measurement of the conversion coefficient, the main methods are the source meter method and the bridge method. The source meter method has the advantages of convenience and directness. The principle of the source meter method is: the current source outputs a standard current value, and the voltmeter measures the output voltage value of the converter. The ratio of the two is the conversion coefficient. Limited by the technical indicators of the current source and voltmeter (such as maximum allowable error and stability), the measurement uncertainty of the source meter method is difficult to exceed 10 -5 Therefore, this method is suitable for situations where the measurement accuracy is not required to be high.

[0005] The bridge method has the advantage of high-accuracy measurement. Relying on the proportional bridge circuit and the null indication technique, the ratio of the conversion coefficients of the converter under test to the standard converter is strictly equal to the ratio of the number of turns of the windings connected to them. The problem is that during the measurement process, the currents of the converter under test and the standard converter increase or decrease in the same proportion, that is, the currents corresponding to the ratio of their conversion coefficients are always in the same proportional relationship. However, the current coefficient of the standard converter objectively exists and cannot be ignored when high-accuracy measurement requirements are encountered. How to measure it remains a problem. If only comparing with a higher-grade standard device again, it will undoubtedly fall into a dead loop and does not fundamentally solve the problem of measuring the current coefficient. Summary of the Invention

[0006] The present invention provides a current coefficient measuring device and a measuring method to solve the technical problem of low accuracy in measuring the current coefficient in the prior art.

[0007] To solve the above technical problem, the present invention provides a current coefficient measuring device, including a first unit, a second unit, a third unit, a fourth unit and a fifth unit;

[0008] The first unit includes a current source, a second current ratio standard, a third current ratio standard, a second standard current-voltage converter and a first voltage test device; the current source, the primary side of the second current ratio standard and the primary side of the third current ratio standard are connected in series; the secondary side of the second current ratio standard is connected in series with the second standard current-voltage converter; the secondary side of the third current ratio standard is connected in series with the current-voltage converter under test; the low-potential ends of the second standard current-voltage converter and the current-voltage converter under test are connected, and the first voltage test device is connected between the high-potential ends of the second standard current-voltage converter and the current-voltage converter under test;

[0009] The second unit includes the current source, the fourth current ratio standardizer, the third standard current-voltage converter, the fourth standard current-voltage converter, and the second voltage testing device; the current source, the primary side of the fourth current ratio standardizer, the third standard current-voltage converter, and the fourth standard current-voltage converter are connected in series, and the third standard current-voltage converter and the fourth standard current-voltage converter are adjacent; the secondary side of the fourth current ratio standardizer is connected in series with the current-voltage converter under test; the low-potential ends of the third standard current-voltage converter and the fourth standard current-voltage converter after being connected in series are connected to the low-potential end of the current-voltage converter under test, and the second voltage testing device is connected between the high-potential ends of the third standard current-voltage converter and the fourth standard current-voltage converter after being connected in series and the high-potential end of the current-voltage converter under test; the ratios of the third current ratio standardizer and the fourth current ratio standardizer are not equal;

[0010] The third unit includes the current source, the third current ratio standardizer, the third standard current-voltage converter, and the third voltage testing device; the current source, the primary side of the third current ratio standardizer, and the third standard current-voltage converter are connected in series; the secondary side of the third current ratio standardizer is connected in series with the current-voltage converter under test; the low-potential end of the third standard current-voltage converter is connected to the low-potential end of the current-voltage converter under test, and the third voltage testing device is connected between the high-potential end of the third standard current-voltage converter and the high-potential end of the current-voltage converter under test;

[0011] The fourth unit includes the current source, the third current ratio standardizer, the fourth standard current-voltage converter, and the fourth voltage testing device; the current source, the primary side of the third current ratio standardizer, and the fourth standard current-voltage converter are connected in series; the secondary side of the third current ratio standardizer is connected in series with the current-voltage converter under test; the low-potential end of the fourth standard current-voltage converter is connected to the low-potential end of the current-voltage converter under test, and the fourth voltage testing device is connected between the high-potential end of the fourth standard current-voltage converter and the high-potential end of the current-voltage converter under test;

[0012] The fifth unit includes the current source, the second current ratio standardizer, an adjustable current ratio conversion device, the second standard current-voltage converter, and a null indicator; the primary sides of the current source and the second current ratio standardizer are connected in series; the secondary side of the second current ratio standardizer and the primary side of the adjustable current ratio conversion device are connected in series; the secondary side of the adjustable current ratio conversion device and the current-voltage converter under test are connected in series; the high-potential end of the second standard current-voltage converter is connected to one end of the secondary side of the second current ratio standardizer; the low-potential end of the second standard current-voltage converter is connected to the low-potential end of the current-voltage converter under test, and the null indicator is connected between the high-potential end of the second standard current-voltage converter and the high-potential end of the current-voltage converter under test.

[0013] Optionally, the current source is a continuously adjustable current source.

[0014] Optionally, the ratio ranges of the second current ratio standardizer, the third current ratio standardizer, and the fourth current ratio standardizer are all 1 to 1000, and the maximum allowable errors are all better than ±5×10 -7 .

[0015] Optionally, the number of turns of the primary winding of the adjustable current ratio conversion device is continuously adjustable, and the number of turns of the secondary winding is fixed.

[0016] Optionally, the nominal values of the conversion coefficients of the second standard current-voltage converter, the third standard current-voltage converter, and the fourth standard current-voltage converter are all in the range of 1 mV / A to 10 V / A.

[0017] Optionally, the first voltage test device, the second voltage test device, the third voltage test device, and the fourth voltage test device are the same voltmeter.

[0018] The present invention also provides another current coefficient measurement device, including a first unit, a second unit, a third unit, a fourth unit, and a fifth unit;

[0019] The first unit includes a current source, a second current ratio standardizer, a third current ratio standardizer, a second standard current-voltage converter, and a first voltage test device; the current source, the primary side of the second current ratio standardizer, and the primary side of the third current ratio standardizer are connected in series; the secondary side of the second current ratio standardizer is connected to the second standard current-voltage converter; the secondary side of the third current ratio standardizer is connected to the current-voltage converter under test; the high-potential end of the second standard current-voltage converter is connected to the high-potential end of the current-voltage converter under test, and the first voltage test device is connected between the low-potential end of the second standard current-voltage converter and the low-potential end of the current-voltage converter under test;

[0020] The second unit includes the current source, the fourth current ratio standard, the third standard current-voltage converter, the fourth standard current-voltage converter, and the second voltage test device; the current source, the primary side of the fourth current ratio standard, the third standard current-voltage converter, and the fourth standard current-voltage converter are connected in series, and the third standard current-voltage converter and the fourth standard current-voltage converter are adjacent; the secondary side of the fourth current ratio standard is connected in series with the current-voltage converter under test; the high-potential end after the third standard current-voltage converter and the fourth standard current-voltage converter are connected in series is connected to the high-potential end of the current-voltage converter under test, and the second voltage test device is connected between the low-potential end after the third standard current-voltage converter and the fourth standard current-voltage converter are connected in series and the low-potential end of the current-voltage converter under test; the ratios of the third current ratio standard and the fourth current ratio standard are not equal;

[0021] The third unit includes the current source, the third current ratio standard, the third standard current-voltage converter, and the third voltage test device; the current source, the primary side of the third current ratio standard, and the third standard current-voltage converter are connected in series; the secondary side of the third current ratio standard is connected in series with the current-voltage converter under test; the high-potential end of the third standard current-voltage converter is connected to the high-potential end of the current-voltage converter under test, and the third voltage test device is connected between the low-potential end of the third standard current-voltage converter and the low-potential end of the current-voltage converter under test;

[0022] The fourth unit includes the current source, the third current ratio standard, the fourth standard current-voltage converter, and the fourth voltage test device; the current source, the primary side of the third current ratio standard, and the fourth standard current-voltage converter are connected in series; the secondary side of the third current ratio standard is connected in series with the current-voltage converter under test; the high-potential end of the fourth standard current-voltage converter is connected to the high-potential end of the current-voltage converter under test, and the fourth voltage test device is connected between the low-potential end of the fourth standard current-voltage converter and the low-potential end of the current-voltage converter under test;

[0023] The fifth unit includes the current source, the second current ratio standardizer, the adjustable current ratio conversion device, the second standard current-voltage converter, and the null indicator; the primary sides of the current source and the second current ratio standardizer are connected in series; the secondary side of the second current ratio standardizer and the primary side of the adjustable current ratio conversion device are connected in series; the secondary side of the adjustable current ratio conversion device and the current-voltage converter to be measured are connected in series; the high-potential end of the second standard current-voltage converter is connected to one end of the secondary side of the second current ratio standardizer; the high-potential end of the second standard current-voltage converter is connected to the high-potential end of the current-voltage converter to be measured, and the null indicator is connected between the low-potential end of the second standard current-voltage converter and the low-potential end of the current-voltage converter to be measured.

[0024] The present invention also provides a method for measuring a current coefficient. The method measures the current coefficient of the current-voltage converter to be measured by using the current coefficient measuring device according to any one of the above. The method includes the following steps:

[0025] Connect the current-voltage converter to be measured to the first unit, the second unit, the third unit, the fourth unit, and the fifth unit respectively;

[0026] Obtain the values of the first voltage test device, the second voltage test device, the third voltage test device, the fourth voltage test device, the ratio value of the second current ratio standardizer, the ratio value of the third current ratio standardizer, the ratio value of the fourth current ratio standardizer, and the ratio value of the adjustable current ratio conversion device respectively;

[0027] According to Determine the current coefficient corresponding to I4, where α represents the current coefficient corresponding to I4, and I4 represents the current flowing through the current-voltage converter to be measured in the second unit. I1 represents the current output by the current source, U1 represents the value of the first voltage test device, U2 represents the value of the second voltage test device, U3 represents the value of the third voltage test device, U4 represents the value of the fourth voltage test device, k2 represents the ratio of the second current ratio standardizer, k3 represents the ratio of the third current ratio standardizer, k4 represents the ratio of the fourth current ratio standardizer, and k5 represents the ratio of the adjustable current ratio conversion device.

[0028] Optionally, the method further includes the following steps:

[0029] Replace the fourth current ratio standard in the second unit with another current ratio standard, where the ratios of the third current ratio standard, the fourth current ratio standard, and the other current ratio standard are all unequal;

[0030] Use the other current ratio standard as the updated fourth current ratio standard;

[0031] According to Determine the current coefficient corresponding to the updated I4.

[0032] A current coefficient measuring device and a measuring method provided by the present invention have the following technical effects:

[0033] 1. By using the difference measurement and null indication techniques, the error introduced by the current ratio standard into the voltage test equipment is the error of the voltage difference, greatly improving the accuracy of the measurement result.

[0034] 2. The standard current-voltage converter is only used for numerical transition, and its conversion coefficient and current coefficient will not affect the measurement result.

[0035] 3. The measurement method strictly conforms to the definition of the current coefficient, can realize the self-comparison of the conversion coefficient values within the range, and meets the requirements for correcting the precise measurement result.

[0036] 4. The five units share the same current source, and the output value of the current source remains unchanged during a single measurement of the current coefficient, so that the output error of the current source is eliminated and will not affect the measurement result. Description of the Drawings

[0037] Figure 1 is a schematic circuit diagram of the first unit in a current coefficient measuring device provided by an embodiment of the present invention.

[0038] Figure 2 is a schematic circuit diagram of the second unit in a current coefficient measuring device provided by an embodiment of the present invention. [[ID=�4]]

[0039] Figure 3 is a schematic circuit diagram of the third unit in a current coefficient measuring device provided by an embodiment of the present invention.

[0040] Figure 4 is a schematic circuit diagram of the fourth unit in a current coefficient measuring device provided by an embodiment of the present invention.

[0041] Figure 5 is a schematic circuit diagram of the fifth unit in a current coefficient measuring device provided by an embodiment of the present invention.

[0042] Figure 6It is a flowchart of a method for measuring current coefficient provided by an embodiment of the present invention.

[0043] [Explanation of reference numerals is as follows]:

[0044] S - Current source;

[0045] k2 - Second current ratio standard, k3 - Third current ratio standard, k4 - Fourth current ratio standard;

[0046] k5 - Adjustable current ratio conversion device;

[0047] R2 - Second standard current - voltage converter, R 21 - Third standard current - voltage converter, R 22 - Fourth standard current - voltage converter;

[0048] V1 - First voltage test device, V2 - Second voltage test device, V3 - Third voltage test device, V4 - Fourth voltage test device;

[0049] G - Null detector;

[0050] R3 - Current - voltage converter under test. Detailed implementation manner

[0051] To make the objectives, advantages, and features of the present invention clearer, the following further details the current coefficient measurement device and measurement method proposed by the present invention with reference to the accompanying drawings. It should be noted that the accompanying drawings are in very simplified forms and use non - precise scales, only for conveniently and clearly assisting in explaining the objectives of the embodiments of the present invention.

[0052] In the description of the present invention, the qualifier terms such as "first", "second", etc. are added for convenient description and reference, and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with qualifier terms such as "first", "second", etc. may explicitly or implicitly include one or more of such features.

[0053] Embodiment 1

[0054] Refer to Figures 1 - 5 As shown, this embodiment provides a current coefficient measurement device, including a first unit, a second unit, a third unit, a fourth unit, and a fifth unit;

[0055] Refer to Figure 1As shown, the first unit includes a current source S, a second current ratio standard k2, a third current ratio standard k3, a second standard current-voltage converter R2, and a first voltage test device V1; the current source S, the primary side of the second current ratio standard k2, and the primary side of the third current ratio standard k3 are connected in series; the secondary side of the second current ratio standard k2 and the second standard current-voltage converter R2 are connected in series; the secondary side of the third current ratio standard k3 and the current-voltage converter under test R3 are connected in series; the low-potential ends of the second standard current-voltage converter R2 and the current-voltage converter under test R3 are connected, and the first voltage test device V1 is connected between the high-potential ends of the second standard current-voltage converter R2 and the current-voltage converter under test R3;

[0056] Reference Figure 2 As shown, the second unit includes the current source S, a fourth current ratio standard k4, a third standard current-voltage converter R 21 , a fourth standard current-voltage converter R 22 and a second voltage test device V2; the current source S, the primary side of the fourth current ratio standard k4, the third standard current-voltage converter R 21 and the fourth standard current-voltage converter R 22 are connected in series, and the third standard current-voltage converter R 21 and the fourth standard current-voltage converter R 22 are adjacent; the secondary side of the fourth current ratio standard k4 and the current-voltage converter under test R3 are connected in series; the low-potential end after the third standard current-voltage converter R 21 and the fourth standard current-voltage converter R 22 are connected in series and the low-potential end of the current-voltage converter under test R3 are connected, and the second voltage test device V2 is connected between the high-potential end after the third standard current-voltage converter R 21 and the fourth standard current-voltage converter R 22 are connected in series and the high-potential end of the current-voltage converter under test R3; the ratios of the third current ratio standard k3 and the fourth current ratio standard k4 are not equal; wherein, the positions of the third standard current-voltage converter R 21 and the fourth standard current-voltage converter R 22 in the circuit can be adjusted. If the current output by the current source S first flows through the third standard current-voltage converter R 21 , and then flows through the fourth standard current-voltage converter R 22 , the third standard current-voltage converter R 21 and the fourth standard current-voltage converter R22 The low-potential end after series connection is the low-potential end of the third standard current-voltage converter R 21 ; if the current output by the current source S first flows through the fourth standard current-voltage converter R 22 , and then through the third standard current-voltage converter R 21 , the low-potential end of the third standard current-voltage converter R 21 and the fourth standard current-voltage converter R 22 after series connection is the low-potential end of the fourth standard current-voltage converter R 22 ; similarly, the high-potential end of the third standard current-voltage converter R 21 and the fourth standard current-voltage converter R 22 after series connection can be the high-potential end of the third standard current-voltage converter R 21 or the high-potential end of the fourth standard current-voltage converter R 22 ;

[0057] Refer to Figure 3 as shown, the third unit includes the current source S, the third current ratio standard k3, the third standard current-voltage converter R 21 and the third voltage test device V3; the current source S, the primary side of the third current ratio standard k3 and the third standard current-voltage converter R 21 are connected in series; the secondary side of the third current ratio standard k3 and the measured current-voltage converter R3 are connected in series; the low-potential end of the third standard current-voltage converter R 21 is connected to the low-potential end of the measured current-voltage converter R3, and the third voltage test device V3 is connected between the high-potential end of the third standard current-voltage converter R 21 and the high-potential end of the measured current-voltage converter R3;

[0058] Refer to Figure 4 as shown, the fourth unit includes the current source S, the third current ratio standard k3, the fourth standard current-voltage converter R 22 and the fourth voltage test device V4; the current source S, the primary side of the third current ratio standard k3 and the fourth standard current-voltage converter R 22 are connected in series; the secondary side of the third current ratio standard k3 and the measured current-voltage converter R3 are connected in series; the low-potential end of the fourth standard current-voltage converter R 22 is connected to the low-potential end of the measured current-voltage converter R3, and the fourth standard current-voltage converter R 22The fourth voltage testing device V4 is connected between the high potential end of and the high potential end of the current-voltage converter R3 under test.

[0059] Reference Figure 5 As shown, the fifth unit includes the current source S, the second current ratio standard k2, the adjustable current ratio conversion device k5, the second standard current-voltage converter R2, and the null indicator G; the primary side of the current source S is connected in series with the primary side of the second current ratio standard k2; the secondary side of the second current ratio standard k2 is connected in series with the primary side of the adjustable current ratio conversion device k5; the secondary side of the adjustable current ratio conversion device k5 is connected in series with the current-voltage converter R3 under test; the high potential end of the second standard current-voltage converter R2 is connected to one end of the secondary side of the second current ratio standard k2; the low potential end of the second standard current-voltage converter R2 is connected to the low potential end of the current-voltage converter R3 under test, and the null indicator G is connected between the high potential end of the second standard current-voltage converter R2 and the high potential end of the current-voltage converter R3 under test.

[0060] Reference Figures 1 - 6 As shown, the principle of the current coefficient measuring device for measuring the current coefficient of the current-voltage converter includes the following steps:

[0061] The first step, reference Figure 1 As shown, the first unit is built. The current output by the current source S is I1, the ratio of the second current ratio standard k2 is k2, the ratio of the third current ratio standard k3 is k3, the conversion coefficient of the second standard current-voltage converter R2 at current I2 is R 2(I2) , the conversion coefficient of the current-voltage converter R3 under test at current I3 is R 3(I3) , k2 and k3 respectively transform the current I1 into I2 and I3, and the first voltage testing device V1 is used to record the voltage difference U1 of the current-voltage converter R3 under test relative to the second standard current-voltage converter R2;

[0062]

[0063] The second step, reference Figure 2 As shown, the second unit is built. The current output by the current source S is I1, the ratio of the fourth current ratio standard k4 is k4, the conversion coefficient of the third standard current-voltage converter R 21 at current I1 is R 2(I2) , the conversion coefficient of the fourth standard current-voltage converter R 22 at current I1 is R 22(I1) , the conversion coefficient of the current-voltage converter R3 under test at current I4 is R3(I4) , k4 converts the current I1 into I4, and the second voltage test device V2 is used to record the voltage difference U2 of the current-voltage converter R3 relative to the third standard current-voltage converter R 21 and the fourth standard current-voltage converter R 22 ;

[0064]

[0065] Step 3: Refer to Figure 3 as shown, build the third unit. The current output by the current source S is I1, the ratio of the third current ratio standard k3 is k3, k3 converts the current I1 into I3, and the third voltage test device V3 is used to record the voltage difference U3 of the measured current-voltage converter R3 relative to the third standard current-voltage converter R 21 ;

[0066]

[0067] Step 4: Refer to Figure 4 as shown, build the fourth unit. The current output by the current source S is I1, the ratio of the third current ratio standard k3 is k3, k3 converts the current I1 into I3, and the third voltage test device V3 is used to record the voltage difference U4 of the measured current-voltage converter R3 relative to the fourth standard current-voltage converter R 22 ;

[0068]

[0069] Step 5: Refer to Figure 5 as shown, build the fifth unit. Adjust the number of turns of the primary winding of the adjustable current ratio conversion device k5 so that the voltages of the measured current-voltage converter R3 and the second standard current-voltage converter R2 are equal. The current output by the current source S is I1, the ratio of the second current ratio standard k2 is k2, k2 converts the current I1 into I2, adjust the number of turns of the primary winding of the adjustable current ratio conversion device k5, record the value of the number of turns of the primary winding when the null indicator G indicates zero, and calculate the ratio k5 of the adjustable current ratio conversion device k5 at this time.

[0070]

[0071] Step 6: Add formula (3) and formula (4), and get:

[0072]

[0073] Subtract formula (2) from formula (6), and get:

[0074]

[0075] Multiply Equation (1) by Equation (7) to obtain:

[0076]

[0077] Substitute Equation (5) into Equation (8) to obtain:

[0078]

[0079] According to the definition of the current coefficient, set the value of current I3 as 10% (starting point) of the upper limit I of the range of the measured current-voltage converter R3, and the value of current I4 as an arbitrary value within the starting point and the range. Then, the current coefficient α of the measured current-voltage converter R3 is:

[0080]

[0081] where R 3(xI) represents the conversion coefficient of the measured current-voltage converter R3 when the current is an arbitrary value within the range, and R 3(10％I) represents the conversion coefficient of the measured current-voltage converter R3 when the current is 10% of the upper limit I of the range. The fourth current ratio standard k4 can be replaced with current ratio standards of different ratios, so that the current I4 can be respectively equal to any value within the range of the measured current-voltage converter R3, and further measure the current coefficients corresponding to any values within the range of the measured current-voltage converter R3.

[0082] A current coefficient measurement device provided in this embodiment has the following technical effects:

[0083] 1. By using the differential measurement and null indication techniques, the error introduced by the current ratio standard into the voltage test equipment is the error of the voltage difference, which greatly improves the accuracy of the measurement result.

[0084] 2. The standard current-voltage converter is only used for numerical transition, and its conversion coefficient and current coefficient will not affect the measurement result.

[0085] 3. The measurement method strictly conforms to the definition of the current coefficient, can realize the self-comparison of the conversion coefficient values within the range, and meets the requirements for correcting the precise measurement results.

[0086] 4. The five units share the same current source, and the output value of the current source remains unchanged during a single measurement of the current coefficient. In this way, the output error of the current source is eliminated and will not affect the measurement result.

[0087] Optionally, when selecting each current ratio standard and each standard current-voltage converter, try to make the voltage differences measured by each voltage test device smaller, which can improve the accuracy of the measurement results.

[0088] Optionally, the current source is a continuously adjustable current source. The continuously adjustable current source can drive the current ratio standard and the current-voltage converter, and the output current is preferably a value that covers the rated current of the current-voltage converter, so that the current coefficient of the current-voltage converter can be measured using the same current source.

[0089] Optionally, the output range of the current source is 0.01 A to 1000 A. The current source provided in this embodiment can measure the current coefficients of most current-voltage converters. In other embodiments, the output current value of the current source can be adjusted according to actual measurement requirements.

[0090] Optionally, refer to Figures 1 - 5 As shown, the ratio ranges of the second current ratio standard k2, the third current ratio standard k3, and the fourth current ratio standard k4 are all 1 to 1000, and the maximum allowable error is better than ±5×10 -7 . The current ratio standards provided in this embodiment can measure the current coefficients of most current-voltage converters. In other embodiments, the ratio values of the current ratio standards can be adjusted according to actual measurement requirements.

[0091] Optionally, refer to Figure 5 As shown, the number of turns of the primary winding of the adjustable current ratio conversion device k5 is continuously adjustable, and the number of turns of the secondary winding is fixed. Optionally, the number of turns of the primary winding of the adjustable current ratio conversion device k5 is continuously adjustable, and the number of turns of the secondary winding is fixed. Optionally, the number of turns of the primary winding of the adjustable current ratio conversion device k5 ranges from 1×10 -6 to 1000 turns, the number of turns of the secondary winding is 1000 turns, the ratio range is 1 to 1×10 6 , the adjustable resolution is 1×10 -9 , and the maximum allowable error is better than ±2×10 -7 . The adjustable current ratio conversion device k5 provided in this embodiment can measure the current coefficients of most current-voltage converters. In other embodiments, the ratio value of the adjustable current ratio conversion device k5 can be adjusted according to actual measurement requirements.

[0092] Optionally, refer to Figures 1 - 5 As shown, the second standard current-voltage converter R2, the third standard current-voltage converter R 21 and the fourth standard current-voltage converter R 22The nominal values of the conversion coefficients are all in the range of 1 mV / A to 10 V / A. The standard current-voltage converter provided in this embodiment can measure the current coefficients of most current-voltage converters. In other embodiments, the conversion coefficient of the standard current-voltage converter can be adjusted according to actual measurement requirements.

[0093] Optionally, referring to Figures 1 - 4 As shown, the first voltage test device V1, the second voltage test device V2, the third voltage test device V3, and the fourth voltage test device V4 are the same voltmeter. This can improve the accuracy of the measurement results and reduce the cost of the device. In other embodiments, the first voltage test device V1, the second voltage test device V2, the third voltage test device V3, and the fourth voltage test device V4 can be independent voltmeters respectively, or other types of voltage measurement devices such as voltage probes.

[0094] Optionally, the voltmeter can automatically switch ranges, and the reading error and resolution meet the measurement requirements of high accuracy.

[0095] Optionally, the reading error of the voltmeter is better than ±1×10 -4 , and the resolution is 10 nV. The voltmeter provided in this embodiment can measure the current coefficients of most current-voltage converters. In other embodiments, the resolution of the voltmeter can be adjusted according to actual measurement requirements.

[0096] Optionally, referring to Figure 5 As shown, the null detector G is a pointer-type instrument, and the pointer swings around zero as the voltage changes, and the resolution meets the measurement requirements of high accuracy.

[0097] Optionally, referring to Figure 5 As shown, the resolution of the null detector is better than 50 nV. The null detector G provided in this embodiment can measure the current coefficients of most current-voltage converters. In other embodiments, the resolution of the null detector G can be adjusted according to actual measurement requirements.

[0098] Embodiment 2:

[0099] Referring to Figures 1 - 5 As shown, based on the same technical concept as the above-mentioned current coefficient measurement device, this embodiment also provides another current coefficient measurement device, which is characterized in that it includes a first unit, a second unit, a third unit, a fourth unit, and a fifth unit;

[0100] The first unit includes a current source S, a second current ratio standard k2, a third current ratio standard k3, a second standard current-voltage converter R2, and a first voltage test device V1; the current source S, the primary side of the second current ratio standard k2, and the primary side of the third current ratio standard k3 are connected in series; the secondary side of the second current ratio standard k2 and the second standard current-voltage converter R2 are connected in series; the secondary side of the third current ratio standard k3 and the current-voltage converter under test R3 are connected in series; the high-potential ends of the second standard current-voltage converter R2 and the current-voltage converter under test R3 are connected, and the first voltage test device V1 is connected between the low-potential ends of the second standard current-voltage converter R2 and the current-voltage converter under test R3;

[0101] The second unit includes the current source S, a fourth current ratio standard k4, a third standard current-voltage converter R 21 , a fourth standard current-voltage converter R 22 , and a second voltage test device V2; the current source S, the primary side of the fourth current ratio standard k4, the third standard current-voltage converter R 21 , and the fourth standard current-voltage converter R 22 are connected in series, and the third standard current-voltage converter R 21 and the fourth standard current-voltage converter R 22 are adjacent; the secondary side of the fourth current ratio standard k4 and the current-voltage converter under test R3 are connected in series; the high-potential end after the third standard current-voltage converter R 21 and the fourth standard current-voltage converter R 22 are connected in series and the high-potential end of the current-voltage converter under test R3 are connected, and the second voltage test device V2 is connected between the low-potential end after the third standard current-voltage converter R 21 and the fourth standard current-voltage converter R 22 are connected in series and the low-potential end of the current-voltage converter under test R3; the ratios of the third current ratio standard k3 and the fourth current ratio standard k4 are not equal;

[0102] The third unit includes the current source S, the third current ratio standard k3, the third standard current-voltage converter R 21 , and a third voltage test device V3; the current source S, the primary side of the third current ratio standard k3, and the third standard current-voltage converter R 21 are connected in series; the secondary side of the third current ratio standard k3 and the current-voltage converter under test R3 are connected in series; the third standard current-voltage converter R 21The high-potential end is connected to the high-potential end of the current-voltage converter R3 to be measured, and the third voltage test device V3 is connected between the low-potential end of the third standard current-voltage converter R 21 and the low-potential end of the current-voltage converter R3 to be measured;

[0103] The fourth unit includes the current source S, the third current ratio standard k3, the fourth standard current-voltage converter R 22 and the fourth voltage test device V4; the current source S, the primary side of the third current ratio standard k3 and the fourth standard current-voltage converter R 22 are connected in series; the secondary side of the third current ratio standard k3 and the current-voltage converter R3 to be measured are connected in series; the high-potential end of the fourth standard current-voltage converter R 22 is connected to the high-potential end of the current-voltage converter R3 to be measured, and the fourth voltage test device V4 is connected between the low-potential end of the fourth standard current-voltage converter R 22 and the low-potential end of the current-voltage converter R3 to be measured;

[0104] The fifth unit includes the current source S, the second current ratio standard k2, the adjustable current ratio conversion device k5, the second standard current-voltage converter R2 and the null indicator G; the current source S and the primary side of the second current ratio standard k2 are connected in series; the secondary side of the second current ratio standard k2 and the primary side of the adjustable current ratio conversion device k5 are connected in series; the secondary side of the adjustable current ratio conversion device k5 and the current-voltage converter R3 to be measured are connected in series; the high-potential end of the second standard current-voltage converter R2 is connected to one end of the secondary side of the second current ratio standard k2; the high-potential end of the second standard current-voltage converter R2 is connected to the high-potential end of the current-voltage converter R3 to be measured, and the null indicator G is connected between the low-potential end of the second standard current-voltage converter R2 and the low-potential end of the current-voltage converter R3 to be measured.

[0105] The main difference between the second embodiment and the first embodiment is that the positions of the voltage test devices change from the high-potential ends of the current-voltage converters to the low-potential ends, and the principle of the derivation formula is the same but the specific form changes slightly.

[0106] Reference Figures 1 - 6 As shown, based on the same technical concept as the above current coefficient measurement device, this embodiment also provides a current coefficient measurement method. The method uses the current coefficient measurement device described in the first embodiment to measure the current coefficient of the current-voltage converter R3 to be measured. The method includes the following steps:

[0107] S1. Connect the current-to-voltage converter under test R3 to the first unit, the second unit, the third unit, the fourth unit, and the fifth unit respectively;

[0108] S2. Obtain the values of the first voltage test device V1, the values of the second voltage test device V2, the values of the third voltage test device V3, the values of the fourth voltage test device V4, the ratio value of the second current ratio standard k2, the ratio value of the third current ratio standard k3, the ratio value of the fourth current ratio standard k4, and the ratio value of the adjustable current ratio conversion device k5 respectively;

[0109] S3. According to Determine the current coefficient corresponding to I4, where α represents the current coefficient corresponding to I4, and I4 represents the current flowing through the current-to-voltage converter under test R3 in the second unit. I1 represents the current output by the current source S, U1 represents the value of the first voltage test device V1, U2 represents the value of the second voltage test device V2, U3 represents the value of the third voltage test device V3, U4 represents the value of the fourth voltage test device V4, k2 represents the ratio of the second current ratio standard k2, k3 represents the ratio of the third current ratio standard k3, k4 represents the ratio of the fourth current ratio standard k4, and k5 represents the ratio of the adjustable current ratio conversion device k5.

[0110] A current coefficient measurement method provided in this embodiment has the following technical effects:

[0111] 1. By using the difference measurement and null indication techniques, the error introduced by the current ratio standard into the voltage test device is the error of the voltage difference, which greatly improves the accuracy of the measurement result.

[0112] 2. The standard current-to-voltage converter is only used for numerical transition, and its conversion coefficient and current coefficient will not affect the measurement result.

[0113] 3. The measurement method strictly conforms to the definition of the current coefficient, can realize the self-comparison of the conversion coefficient values within the range, and meets the requirements for correcting the precise measurement results.

[0114] 4. The five units share the same current source, and the output value of the current source remains unchanged when measuring the current coefficient once, so that the output error of the current source is eliminated and will not affect the measurement result.

[0115] Optionally, the method further includes the following steps: replacing the fourth current ratio standard k4 in the second unit with another current ratio standard, where the ratios of the third current ratio standard k3, the fourth current ratio standard k4, and the other current ratio standard are not equal; using the other current ratio standard as the updated fourth current ratio standard k4; according to Determine the current coefficient corresponding to the updated I4. Replace the fourth current ratio standard k4 with a current ratio standard of a different ratio, so that the current I4 can be equal to any value within the range of the measured current voltage converter R3, and then measure the current coefficients corresponding to any values within the range of the measured current voltage converter R3.

[0116] As a specific measurement case, the following measures a high-performance current voltage converter through a current coefficient measurement device and the measurement method described in Example 1. The specific data is shown in the following table:

[0117]

[0118] As can be seen from the above table, using a current coefficient measurement device and measurement method provided by the present invention, the current coefficients within the range of the current voltage converter can be measured, and the measurement results are accurate.

[0119] In summary, a current coefficient measurement device and measurement method provided by the present invention have the following technical effects:

[0120] 1. By adopting the differential measurement and null indication technology, the error introduced by the current ratio standard into the voltage test equipment is the error of the voltage difference, which greatly improves the accuracy of the measurement results.

[0121] 2. The standard current voltage converter is only used for numerical transition, and its conversion coefficient and current coefficient will not affect the measurement results.

[0122] 3. The measurement method strictly conforms to the definition of the current coefficient, can realize the self-comparison of the conversion coefficient values within the range, and meets the requirements for correcting the precise measurement results.

[0123] 4. The five units share the same current source, and the output value of the current source remains unchanged during a single measurement of the current coefficient, so that the output error of the current source is eliminated and will not affect the measurement results.

[0124] The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention in any way. Any changes and modifications made by those of ordinary skill in the art according to the above disclosure belong to the protection scope of the present invention.

Claims

1. A current coefficient measuring device, characterized in that, It includes a first unit, a second unit, a third unit, a fourth unit and a fifth unit; The first unit includes a current source, a second current ratio standard, a third current ratio standard, a second standard current-voltage converter and a first voltage testing device; the current source, the primary side of the second current ratio standard and the primary side of the third current ratio standard are connected in series; the secondary side of the second current ratio standard and the second standard current-voltage converter are connected in series; the secondary side of the third current ratio standard and the current-voltage converter under test are connected in series; the low-potential ends of the second standard current-voltage converter and the current-voltage converter under test are connected, and the first voltage testing device is connected between the high-potential ends of the second standard current-voltage converter and the current-voltage converter under test; The second unit includes the current source, a fourth current ratio standard, a third standard current-voltage converter, a fourth standard current-voltage converter and a second voltage testing device; the current source, the primary side of the fourth current ratio standard, the third standard current-voltage converter and the fourth standard current-voltage converter are connected in series, and the third standard current-voltage converter and the fourth standard current-voltage converter are adjacent; the secondary side of the fourth current ratio standard and the current-voltage converter under test are connected in series; the low-potential end after the third standard current-voltage converter and the fourth standard current-voltage converter are connected in series and the low-potential end of the current-voltage converter under test are connected, and the second voltage testing device is connected between the high-potential end after the third standard current-voltage converter and the fourth standard current-voltage converter are connected in series and the high-potential end of the current-voltage converter under test; the ratios of the third current ratio standard and the fourth current ratio standard are not equal; The third unit includes the current source, the third current ratio standard, the third standard current-voltage converter and a third voltage testing device; the current source, the primary side of the third current ratio standard and the third standard current-voltage converter are connected in series; the secondary side of the third current ratio standard and the current-voltage converter under test are connected in series; the low-potential end of the third standard current-voltage converter and the low-potential end of the current-voltage converter under test are connected, and the third voltage testing device is connected between the high-potential end of the third standard current-voltage converter and the high-potential end of the current-voltage converter under test; The fourth unit includes the current source, the third current ratio standardizer, the fourth standard current-voltage converter, and the fourth voltage test device; the current source, the primary side of the third current ratio standardizer, and the fourth standard current-voltage converter are connected in series; the secondary side of the third current ratio standardizer and the measured current-voltage converter are connected in series; the low-potential end of the fourth standard current-voltage converter is connected to the low-potential end of the measured current-voltage converter, and the fourth voltage test device is connected between the high-potential end of the fourth standard current-voltage converter and the high-potential end of the measured current-voltage converter; The fifth unit includes the current source, the second current ratio standardizer, the adjustable current ratio conversion device, the second standard current-voltage converter, and the null indicator; the current source and the primary side of the second current ratio standardizer are connected in series; the secondary side of the second current ratio standardizer and the primary side of the adjustable current ratio conversion device are connected in series; the secondary side of the adjustable current ratio conversion device and the measured current-voltage converter are connected in series; the high-potential end of the second standard current-voltage converter is connected to one end of the secondary side of the second current ratio standardizer; the low-potential end of the second standard current-voltage converter is connected to the low-potential end of the measured current-voltage converter, and the null indicator is connected between the high-potential end of the second standard current-voltage converter and the high-potential end of the measured current-voltage converter.

2. The current coefficient measuring device according to claim 1, wherein The current source is a continuously adjustable current source.

3. The current coefficient measuring device according to claim 1, characterized in that The ratio ranges of the second current ratio standard, the third current ratio standard, and the fourth current ratio standard are all 1 to 1000, and the maximum allowable errors are all better than ±5×10 -7 .

4. The current coefficient measuring device according to claim 1, characterized in that, The number of turns of the primary winding of the adjustable current ratio conversion device is continuously adjustable, and the number of turns of the secondary winding is fixed.

5. The current coefficient measuring device according to claim 1, wherein The nominal values of the conversion coefficients of the second standard current-voltage converter, the third standard current-voltage converter, and the fourth standard current-voltage converter are all in the range of 1 mV / A to 10 V / A.

6. The current coefficient measuring device according to claim 1, wherein, The first voltage test device, the second voltage test device, the third voltage test device, and the fourth voltage test device are the same voltmeter.

7. A current coefficient measuring device, characterized in that, It includes a first unit, a second unit, a third unit, a fourth unit, and a fifth unit; The first unit includes a current source, a second current ratio standardizer, a third current ratio standardizer, a second standard current-voltage converter, and a first voltage test device; the current source, the primary side of the second current ratio standardizer, and the primary side of the third current ratio standardizer are connected in series; the secondary side of the second current ratio standardizer and the second standard current-voltage converter are connected in series; the secondary side of the third current ratio standardizer and the measured current-voltage converter are connected in series; the high-potential end of the second standard current-voltage converter is connected to the high-potential end of the measured current-voltage converter, and the first voltage test device is connected between the low-potential end of the second standard current-voltage converter and the low-potential end of the measured current-voltage converter; The second unit includes the current source, the fourth current ratio standardizer, the third standard current-voltage converter, the fourth standard current-voltage converter, and the second voltage testing device; the current source, the primary side of the fourth current ratio standardizer, the third standard current-voltage converter, and the fourth standard current-voltage converter are connected in series, and the third standard current-voltage converter and the fourth standard current-voltage converter are adjacent; the secondary side of the fourth current ratio standardizer and the current-voltage converter under test are connected in series; the high-potential end after the third standard current-voltage converter and the fourth standard current-voltage converter are connected in series is connected to the high-potential end of the current-voltage converter under test, and the second voltage testing device is connected between the low-potential end after the third standard current-voltage converter and the fourth standard current-voltage converter are connected in series and the low-potential end of the current-voltage converter under test; the ratios of the third current ratio standardizer and the fourth current ratio standardizer are not equal; The third unit includes the current source, the third current ratio standardizer, the third standard current-voltage converter, and the third voltage testing device; the current source, the primary side of the third current ratio standardizer, and the third standard current-voltage converter are connected in series; the secondary side of the third current ratio standardizer and the current-voltage converter under test are connected in series; the high-potential end of the third standard current-voltage converter is connected to the high-potential end of the current-voltage converter under test, and the third voltage testing device is connected between the low-potential end of the third standard current-voltage converter and the low-potential end of the current-voltage converter under test; The fourth unit includes the current source, the third current ratio standardizer, the fourth standard current-voltage converter, and the fourth voltage testing device; the current source, the primary side of the third current ratio standardizer, and the fourth standard current-voltage converter are connected in series; the secondary side of the third current ratio standardizer and the current-voltage converter under test are connected in series; the high-potential end of the fourth standard current-voltage converter is connected to the high-potential end of the current-voltage converter under test, and the fourth voltage testing device is connected between the low-potential end of the fourth standard current-voltage converter and the low-potential end of the current-voltage converter under test; The fifth unit includes the current source, the second current ratio standardizer, an adjustable current ratio conversion device, the second standard current-voltage converter, and a null indicator; the primary side of the current source and the second current ratio standardizer are connected in series; the secondary side of the second current ratio standardizer and the primary side of the adjustable current ratio conversion device are connected in series; the secondary side of the adjustable current ratio conversion device and the current-voltage converter under test are connected in series; the high potential end of the second standard current-voltage converter is connected to one end of the secondary side of the second current ratio standardizer; the high potential end of the second standard current-voltage converter is connected to the high potential end of the current-voltage converter under test, and the null indicator is connected between the low potential end of the second standard current-voltage converter and the low potential end of the current-voltage converter under test.

8. A method for measuring a current coefficient, characterized in that, The method measures the current coefficient of the current-voltage converter under test by using a current coefficient measurement device according to any one of claims 1-7, and the method includes the following steps: Connect the current-voltage converter under test to the first unit, the second unit, the third unit, the fourth unit, and the fifth unit respectively; Obtain the values of the first voltage test device, the values of the second voltage test device, the values of the third voltage test device, the values of the fourth voltage test device, the ratio value of the second current ratio standardizer, the ratio value of the third current ratio standardizer, the ratio value of the fourth current ratio standardizer, and the ratio value of the adjustable current ratio conversion device respectively; According to determine the current coefficient corresponding to I4, where α represents the current coefficient corresponding to I4, and I4 represents the current flowing through the current-voltage converter under test in the second unit, I1 represents the current output by the current source, U1 represents the value of the first voltage testing device, U2 represents the value of the second voltage testing device, U3 represents the value of the third voltage testing device, U4 represents the value of the fourth voltage testing device, k2 represents the ratio of the second current ratio standard, k3 represents the ratio of the third current ratio standard, k4 represents the ratio of the fourth current ratio standard, and k5 represents the ratio of the adjustable current ratio conversion device.

9. A method for measuring a current coefficient according to claim 8, characterized in that, The method further includes the following steps: Replace the fourth current ratio standardizer in the second unit with another current ratio standardizer, and the ratios of the third current ratio standardizer, the fourth current ratio standardizer, and the other current ratio standardizer are not equal; Use the other current ratio standard as the updated fourth current ratio standard; according to Determine the current coefficient corresponding to the updated I4.

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