CN112946560B - Electric energy meter calibration method and device, electric energy meter and electric energy meter system - Google Patents
Electric energy meter calibration method and device, electric energy meter and electric energy meter system Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 55
- 238000005070 sampling Methods 0.000 claims description 19
- 238000005259 measurement Methods 0.000 claims description 17
- 238000004364 calculation method Methods 0.000 claims description 9
- 230000002093 peripheral effect Effects 0.000 description 5
- 238000012545 processing Methods 0.000 description 5
- 238000011088 calibration curve Methods 0.000 description 4
- HPDFFVBPXCTEDN-UHFFFAOYSA-N copper manganese Chemical compound [Mn].[Cu] HPDFFVBPXCTEDN-UHFFFAOYSA-N 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000013528 artificial neural network Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
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- 238000004088 simulation Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass
- G01R35/04—Testing or calibrating of apparatus covered by the other groups of this subclass of instruments for measuring time integral of power or current
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R22/00—Arrangements for measuring time integral of electric power or current, e.g. electricity meters
- G01R22/06—Arrangements for measuring time integral of electric power or current, e.g. electricity meters by electronic methods
Abstract
The application relates to an electric energy meter calibration method and device, an electric energy meter and an electric energy meter system. The method comprises the following steps: after receiving standard currents of different grades output by a standard source, acquiring real-time currents corresponding to the standard currents, obtaining gain data according to the standard currents and the real-time currents, and obtaining calibration parameters based on a gain curve, so that calibration can be performed according to the calibration parameters. According to the method, gain data and calibration parameters are obtained based on a plurality of standard currents and a plurality of real-time currents, and the current values detected by the electric energy meter are calibrated according to the calibration parameters, so that the current calibration in a large range can be realized, the problem that the calibration result is inaccurate after single-point calibration due to nonlinearity of components is solved, the influence of nonlinearity of the components on the calibration is reduced, the accuracy of the calibration result is improved, and the accuracy of the electric energy meter can be improved in a large working range, so that the use reliability of the electric energy meter is improved.
Description
Technical Field
The application relates to the technical field of electric energy meters, in particular to an electric energy meter calibration method, an electric energy meter calibration device, an electric energy meter and an electric energy meter system.
Background
The electric energy meter is a meter for measuring electric energy, also known as an electric meter, a fire meter, a kilowatt hour meter and the like, is widely applied to the families of residents or other occasions, can be used for measuring and counting the used electric energy, and is convenient for monitoring the electricity consumption condition. In order to improve the accuracy of the detection result, the electric energy meter needs to be calibrated before leaving the factory, and the errors of the peripheral circuit and the sampling components are corrected.
Conventional methods of calibrating electrical energy meters include single point calibration, i.e., selecting a fixed current point over the entire measurement range, and calibrating the current over the entire measurement range with the calibration value of the current point. However, since the direct current electric energy meter usually adopts a hall sensor or a manganese copper as a sampling element of current, and the hall sensor and the manganese copper have nonlinearity, other components with nonlinearity may exist on a circuit, so that calibration in a large working range cannot be realized in a single-point calibration mode in a calibration process, a calibration result is inaccurate, and the use is unreliable.
Disclosure of Invention
Aiming at the problem that the traditional electric energy meter calibration method is unreliable in use, the application provides an electric energy meter calibration method, an electric energy meter calibration device, an electric energy meter and an electric energy meter system.
An electric energy meter calibration method comprises the following steps:
receiving standard currents of different grades output by a standard source;
acquiring a real-time current corresponding to the standard current; the real-time current is a current reading value of the electric energy meter after receiving the standard current;
gain data are obtained according to the standard current and the real-time current;
obtaining calibration parameters based on the gain data; the calibration formula is used for calibrating the electric energy meter.
The utility model provides an electric energy meter calibration device, includes sampling circuit and treater, sampling circuit is used for receiving the different grade standard current that standard source output, obtain the real-time electric current that corresponds with the standard current, the real-time electric current is the electric energy meter current reading after receiving the standard current, the treater is used for carrying out electric energy meter calibration according to above-mentioned method.
An electric energy meter comprises the electric energy meter calibrating device.
An electric energy meter system comprising a standard source and an electric energy meter as described above.
According to the electric energy meter calibration method, the electric energy meter calibration device, the electric energy meter and the electric energy meter system, after receiving standard currents of different grades output by the standard source, real-time currents corresponding to the standard currents are obtained, gain data are obtained according to the standard currents and the real-time currents, calibration parameters are obtained based on the gain data, and therefore calibration can be conducted according to the calibration parameters. According to the method, gain data and calibration parameters are obtained based on a plurality of standard currents and a plurality of real-time currents, and the current values detected by the electric energy meter are calibrated according to the calibration parameters, so that the current calibration in a large range can be realized, the problem that the calibration result is inaccurate after single-point calibration due to nonlinearity of components is solved, the influence of nonlinearity of the components on the calibration is reduced, the accuracy of the calibration result is improved, and the accuracy of the electric energy meter can be improved in a large working range, so that the use reliability of the electric energy meter is improved.
In one embodiment, the gain data includes a gain curve, and the obtaining gain data according to the standard current and the real-time current includes:
taking the ratio of the standard current to the corresponding real-time current as a current gain value;
drawing a curve according to the zero offset value and the current gain value corresponding to each real-time current, and taking the curve as a gain curve; and the zero offset value is a current reading value of the electric energy meter when the standard source outputs 0 ampere of current.
In one embodiment, the obtaining calibration parameters based on the gain data includes:
dividing the real-time current into different current intervals, and obtaining calibration parameters corresponding to the different current intervals based on the gain data.
In one embodiment, the dividing the real-time current into different current intervals, and obtaining calibration parameters corresponding to the different current intervals based on the gain data includes:
and carrying out linear calculation on the end point value of each current interval and the current gain value corresponding to each end point value, and taking the obtained linear calibration parameter as the calibration parameter corresponding to different current intervals.
In one embodiment, after obtaining the calibration parameter based on the gain data, the method further includes:
and calibrating the current value detected by the electric energy meter according to the calibration parameter to obtain an accurate measurement value of the electric energy meter.
In one embodiment, the calibrating the current value detected by the electric energy meter according to the calibration parameter to obtain an accurate measurement value of the electric energy meter includes:
calculating to obtain real-time current gain according to the calibration parameters and the current value detected by the electric energy meter;
and obtaining an accurate metering value of the electric energy meter according to the current value detected by the electric energy meter and the real-time current gain.
In one embodiment, the calculating the real-time current gain according to the calibration parameter and the current value detected by the electric energy meter includes:
acquiring a current interval in which a current value detected by an electric energy meter is located;
and calculating to obtain the real-time current gain according to the calibration parameters corresponding to the current interval in which the current value detected by the electric energy meter is located.
In one embodiment, the calibrating the current value detected by the electric energy meter according to the calibration parameter to obtain an accurate measurement value of the electric energy meter includes:
calibrating the current value detected by the electric energy meter according to the calibration parameter, and obtaining an accurate measurement value of the electric energy meter according to the calibrated current value and the zero offset value; and the zero offset value is a current reading value of the electric energy meter when the standard source outputs 0 ampere of current.
In one embodiment, after obtaining the calibration parameter based on the gain data, the method further includes:
when receiving the current in the opposite direction, returning to the receiving standard current of different grades output by the standard source.
Drawings
FIG. 1 is a flow chart of a method of calibrating a power meter in one embodiment;
FIG. 2 is a flow chart of a method of calibrating a power meter according to another embodiment;
FIG. 3 is a flow chart of a method of calibrating a power meter according to another embodiment;
FIG. 4 is a flow chart of a method of calibrating a power meter according to yet another embodiment;
FIG. 5 is a flow chart of a method of calibrating a power meter in yet another embodiment;
FIG. 6 is a schematic diagram of a connection between an electric energy meter and a standard source in one embodiment;
FIG. 7 is a graph of calculated gain for one embodiment;
FIG. 8 is a schematic diagram of the operation of the power meter calibration device in one embodiment;
FIG. 9 is a flow chart of calibrating a power meter in one embodiment.
Detailed Description
The present application will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the application are shown. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.
In one embodiment, an electric energy meter calibration method is provided, and the method is mainly applied to calibration of a direct current electric energy meter, wherein a current sampling element of the direct current electric energy meter comprises a Hall sensor or manganese copper and the like. The method can be executed by a separate calibrating device independent of the electric energy meter, so that the electric energy meter can be calibrated, the built-in calibrating device of the electric energy meter can be adopted, the hardware cost is saved, and the utilization rate of devices is improved. In this embodiment, the calibration of the electric energy meter by using the calibration device built in the electric energy meter is described as an example, the calibration device built in the electric energy meter includes a sampling circuit and a processor, the sampling circuit is used for sampling, and the processor is used for analyzing and processing the data obtained by sampling the sampling circuit. Referring to fig. 1, the method for calibrating the electric energy meter includes the following steps:
step S100: different levels of standard current output by a standard source are received.
Specifically, the sampling circuit can receive standard currents of different levels output by the standard source, and transmit the received standard currents to the processor for subsequent processing. The standard source is an instrument capable of outputting voltage and current with high precision and stability, and referring to fig. 6, the standard source is connected with the electric energy meter, and can output standard voltage and standard current with different grades to the electric energy meter, and the electric energy meter is calibrated according to the standard value.
Step S300: and acquiring real-time current corresponding to the standard current.
The real-time current is a current reading value of the electric energy meter after receiving the standard current. After the standard current reaches the electric energy meter, the standard current reaches a metering chip of the electric energy meter through some circuits or devices in the electric energy meter, and the metering chip generates a current reading value after processing. Because the devices or peripheral circuits in the electric energy meter can have errors, the current reading value generated after passing through the devices is different from the current actually received by the electric energy meter before passing through the devices, and the readings of the electric energy meter are inaccurate. Thus, after the standard current and the real-time current corresponding to the standard current are obtained, a subsequent calibration process can be performed based on the standard current and the real-time current. It can be understood that the metering chip of the ammeter can also be matched with other devices, for example, when the processor in the calibrating device is an MCU, the metering chip is matched with the MCU for use, the metering chip is specially responsible for metering, and the MCU is responsible for processing other data. The processor in the calibration device may comprise an ADC and an MCU, and the metering and data processing is done by the MCU through a software algorithm.
Step S500: gain data is obtained based on the standard current and the real-time current.
After the standard current and the real-time current are obtained, the standard current and the real-time current can be calculated to obtain gain data. The type of the gain data is not unique, for example, the gain curve can be obtained by drawing the gain curve with each current value as an abscissa and the gain value corresponding to each current value as an ordinate, and the gain curve can reflect the change condition of the gain value in the whole working current range, so as to reflect the change condition of the error magnitude of the electric energy meter in the whole working current range. Further, the data corresponding to the abscissa of the gain curve is not unique, and may be a real-time current value or a standard current value, and may be adjusted according to the actual situation, so long as the whole abscissa adopts a current value type. The type of gain value is not unique, as long as the difference between the standard current and the real-time current can be reflected in general.
Step S700: calibration parameters are derived based on the gain data.
The calibration parameters are used for calibrating the electric energy meter. After gain data is obtained, calibration parameters may be obtained based on the gain data. The application mode of the calibration parameters is not unique, for example, the calibration parameters and different formula models are combined together to obtain a calibration formula, the method for obtaining the calibration formula is not unique, a formula model which is relatively close to the calibration formula can be selected according to the shape of the gain curve, and then the values of the standard current and the real-time current are substituted into the formula model to obtain the calibration formula which is applicable in the whole current range or the partial current range.
In one embodiment, the gain data includes a gain curve, and referring to fig. 3, step S500 includes step S510 and step S520.
Step S510: the ratio of the standard current to the corresponding real-time current is taken as the current gain value.
The type of the current gain value is not unique, in this embodiment, the current gain value is a ratio of the standard current to the corresponding real-time current, and the ratio can accurately reflect the difference degree of the standard current and the corresponding real-time current. It will be appreciated that in other embodiments, the current gain value may also be the difference between the standard current and the corresponding real-time current, etc., as long as those skilled in the art recognize this as being achievable.
Step S520: and drawing a curve according to the zero offset value and the current gain value corresponding to each real-time current to serve as a gain curve.
The zero offset value is a current reading value of the electric energy meter when the standard source outputs 0 ampere of current. It is understood that the zero offset value is the initial reading of the ammeter. When the curve is drawn, the zero offset value is eliminated firstly, then gain calibration is carried out, the obtained gain curve is the curve with the zero offset value eliminated, and the accuracy of the gain curve is improved.
The gain curve can reflect the change condition of the gain value in the whole working current range, so as to reflect the change condition of the error of the electric energy meter in the whole working current range. Further, the data corresponding to the abscissa of the gain curve is not unique, and may be a real-time current value or a standard current value. When the abscissa of the gain curve is a real-time current value, the gain curve can reflect the change condition of the gain value in the whole real-time current range, and based on the change condition, the calibration in the whole working range can be realized, so that the accuracy of the electric energy meter in the whole working range is improved.
In one embodiment, referring to fig. 3, step S700 includes step S710.
Step S710: and dividing the real-time current into different current intervals, and obtaining calibration parameters corresponding to the different current intervals based on the gain data.
Taking the example that the gain data includes a gain curve, the data corresponding to the abscissa of the gain curve is a real-time current value, the curve characteristics of the gain curve in the whole real-time current range may not be uniform, and there may be cases that different curve characteristics correspond to different real-time current ranges. At this time, the real-time current is divided into different current intervals, and then gain curves in the different current intervals are analyzed respectively to obtain calibration parameters corresponding to the different current intervals, so that the calibration requirements under more conditions can be met, the obtained calibration formula is more fit with the actual conditions, and the accuracy of the calibration formula is improved.
In one embodiment, referring to fig. 4, step S710 includes step S712.
Step S712: and carrying out linear calculation on the end point value of each current interval and the current gain value corresponding to each end point value, and taking the obtained linear calibration parameter as the calibration parameter corresponding to different current intervals.
The method for obtaining the calibration parameters is different according to the different characteristics of the gain curves in the current intervals. In this embodiment, when the gain curves in the current intervals are all approximately linearly changed, linear calculation may be performed on the end values of the current intervals and the current gain values corresponding to the end values, and the obtained linear calibration parameters may be used as the calibration parameters corresponding to different current intervals. Specifically, the calibration values of the end points at the two ends of each current interval line segment are taken for linear calculation, and if points A0 (x 0, y 0) and A1 (x 1, y 1) are known, the gain value of any point a (x, y) between the points is:
y＝(y1-y0)/(x1-x0)*(x-x0)+y0
the formula is a linear calibration formula in a corresponding current interval, wherein the fixed value parameter is a linear calibration parameter. Further, the obtained linear calibration parameters and the linear calibration formulas corresponding to the current intervals are stored in a memory. When the electric energy meter is electrified, the linear calibration parameters and the linear calibration formulas corresponding to the current segments are acquired from the memory, and then the electric energy meter is calibrated according to the linear calibration parameters or the linear calibration formulas.
Correspondingly, the dividing manner of dividing the real-time current into different current intervals is not unique, and can be determined according to the curve characteristics of the gain curve. In this embodiment, the graph is a current gain curve measured by the ammeter, and based on the curve, the whole current gain curve can be divided into seven sections, the first section: 30A-10A, second section: 10A-5A, third section: 5A-3A, fourth paragraph: 3A-1.5A, fifth section: 1.5A-1.0A, sixth paragraph: 1.0A-0.5A, seventh paragraph: 0.5A-0.3A, considering that the gain curve is approximately linear in each section, the end point value of each current interval and the current gain value corresponding to each end point value can be linearly calculated, and the obtained linear calibration formula is used as the calibration formula corresponding to different current intervals. It will be appreciated that in other embodiments, different current intervals may be divided according to other criteria, as long as those skilled in the art deem it possible.
In one embodiment, referring to fig. 2, after step S700, the electric energy meter calibration method further includes step S900.
Step S900: and calibrating the current value detected by the electric energy meter according to the calibration parameters to obtain an accurate metering value of the electric energy meter.
After the calibration parameters are obtained, the current value detected by the electric energy meter can be calibrated according to the calibration parameters, and the accuracy of the reading value of the electric energy meter is improved. Specifically, in the actual use process of the electric energy meter, a calibration formula is obtained according to parameters, after the electric energy meter detects a current value, the detected current value is substituted into the calibration formula to obtain a calibrated current calibration value, and then the type of the current calibration value and the accurate measurement value of the electric energy meter are combined. Specifically, the manner of obtaining the accurate measurement value of the electric energy meter is not unique according to different types of calibrated current calibration values, for example, when the calibrated current calibration value is a current difference value, the sum or product of the current value detected by the current meter and the calibrated current calibration value can be used as the calibrated current calibration value. The type of the calibration formula and the type of the calibrated current calibration value can be other, and the manner of calculating the accurate measurement value of the electric energy meter is also adjusted accordingly, so long as the accurate measurement value can be realized by the person skilled in the art. After the accurate metering value of the electric energy meter is obtained, the accurate metering value is used as the reading display of the electric energy meter, so that a user obtains the accurate current reading value, and the use reliability of the electric energy meter is improved.
Accurate metering of current means that the current value calculated by the ammeter is close to the current value output by the standard source, which is also the purpose of calibration. Because of errors of peripheral circuits and devices, a standard source outputs a standard current/voltage to a direct-current meter under the condition of no calibration, and a relatively large error exists between the current/voltage calculated by the direct-current meter and the standard value, the calculated value of the electric energy meter can be corrected by the electric energy meter calibration method provided by the application, so that the current/voltage calculated by the electric energy meter is close to the standard value, and the accuracy of the electric energy meter is improved.
In one embodiment, referring to fig. 3, step S900 includes step S910 and step S920.
Step S910: and calculating to obtain the real-time current gain according to the calibration parameters and the current value detected by the electric energy meter.
In the actual use process of the electric energy meter, after the electric energy meter detects a current value, the real-time current gain can be calculated according to the calibration parameters and the current value detected by the electric energy meter, and the real-time current gain can be used as a basis for obtaining an accurate measurement value.
Step S920: and obtaining an accurate metering value of the electric energy meter according to the current value detected by the electric energy meter and the real-time current gain.
It is understood that the real-time current gain characterizes the difference between the current value detected by the electric energy meter and the standard value. The manner of obtaining accurate measurement values of the electric energy meter is different according to different types of real-time current gain. For example, when the real-time current gain is a ratio, the product of the current value detected by the ammeter and the real-time current gain can be used as an accurate measurement value of the electric energy meter, and when the real-time current gain is a difference value, the sum of the current value detected by the ammeter and the real-time current gain can be used as the accurate measurement value of the electric energy meter. The accurate measurement value of the current is the current value calculated by the ammeter and is close to the current value output by the standard source, and the purpose of calibration is also achieved. Because of errors of peripheral circuits and devices, a standard source outputs a standard current/voltage to a direct-current meter under the condition of no calibration, and a relatively large error exists between the current/voltage calculated by the direct-current meter and the standard value, the calculated value of the electric energy meter can be corrected by the electric energy meter calibration method provided by the application, so that the current/voltage calculated by the electric energy meter is close to the standard value, and the accuracy of the electric energy meter is improved.
In one embodiment, referring to fig. 4, step S910 includes step S912 and step S914.
Step S912: and acquiring a current interval in which the current value detected by the electric energy meter is.
Specifically, since the calibration formulas may include different calibration formulas corresponding to different current intervals, in the actual use process of the electric energy meter, when the electric energy meter detects a current value, the current interval in which the current value detected by the electric energy meter is located is obtained, so that the most accurate calibration formula is matched, and the accuracy of the calibration result is improved.
Step S914: and calculating to obtain the real-time current gain according to the calibration parameters corresponding to the current interval in which the current value detected by the electric energy meter is located.
After the current interval where the current value detected by the electric energy meter is located is obtained, the real-time current gain is obtained through calculation according to the calibration parameters corresponding to the current interval where the current value detected by the electric energy meter is located, so that different detection currents are matched with different calibration formulas, and the accuracy of the calibration result is improved.
In one embodiment, after step S700, the electric energy meter calibration method further comprises step 800.
Step 800: when receiving the current in the opposite direction, the process returns to step S100.
Specifically, currents in opposite directions refer to the flow directions of the currents being different. When the included angle between the voltage and the current is 0 DEG, the power is a positive number at the moment, and the corresponding current direction is positive. When the angle between the voltage and the current is 180 deg., the power is a negative number, corresponding to the current reversal. The direction of current through components on the meter may be different, and the resulting errors may be different, so that separate calibration of forward and reverse currents may be required due to the asymmetry of the component characteristics. Taking fig. 6 as an example, the current of the standard source is output from i+ and flows through the electric energy meter from output-to input-, and then from I-back to the standard source. The power measured at this point will be a positive value and the current will be a forward current. However, when the current output lines I+ and I-of the standard source are swapped, i.e. the current of the standard source is output from I+, flows through the electric energy meter from input-to output-, and then returns from I-to the standard source. The power measured at this point will be a negative value and the current will be a reverse current in the opposite direction to the previous current.
When the electric energy meter is connected with the forward current and the reverse current respectively, the sampling voltage or the sampling current from the sampling circuit to the metering chip end may not be completely consistent, and therefore, the gain calibration curve of the forward current and the reverse current may not be completely consistent. When receiving the current in the opposite direction, returning to the step S100, and performing calibration again, the forward current and the reverse current can be calibrated separately, so that two calibration curves, namely two sets of calibration formulas, can be obtained, and the calibration requirement of the electric energy meter for accessing the forward current and the reverse current can be met.
For a better understanding of the above embodiments, a detailed explanation is provided below in connection with a specific embodiment. In one embodiment, the electric energy meter is a direct current electric energy meter, and the electric energy meter calibration method comprises: first, when the standard source outputs 0A, the reading I0 of the dc meter is read, and this value is taken as the zero offset value i_offset=i0 of the dc meter. The standard source is an instrument that can output voltages and currents with high accuracy and stability. The function to be realized is that the standard source outputs standard voltages and standard currents of different grades to the direct current meter, and the direct current meter is calibrated according to the standard value. And under the condition that gain calibration is not performed, when different levels of current are output to the direct current meter by using the standard source, obtaining a current reading value of the direct current meter, and calculating a current reading value I of the direct current meter and a standard source output value I ', so as to obtain a current gain value IRMSGain=I'/I at each current point. The calculated current gain values at each current point are plotted as a curve, with the results shown. As can be seen, at small currents, the current gain changes rapidly and non-linearly.
The current gain curve is approximately divided into a plurality of linear line segments according to the current value according to the requirement, and the calibration values of the end points of the two ends of the line segments are taken for linear calculation. Referring to fig. 7, the overall current gain curve can be divided into seven segments, the first segment: 30A-10A, second section: 10A-5A, third section: 5A-3A, fourth paragraph: 3A-1.5A, fifth section: 1.5A-1.0A, sixth paragraph: 1.0A-0.5A, seventh paragraph: 0.5A to 0.3A, the gain curve is considered to be approximately linear in each section, so that linear calculation can be performed on the end value of each current section and the current gain value corresponding to each end value. If points A0 (x 0, y 0) and A1 (x 1, y 1) are known, the gain value of any point a (x, y) between these two points is:
y＝(y1-y0)/(x1-x0)*(x-x0)+y0
and storing the obtained several segments of linear calibration formulas into a memory. When the ammeter is electrified, the calibration formula parameters of the calculation gain of each current segment are acquired from a memory.
In the actual use process of the ammeter, please refer to fig. 9, when the power-on is initialized, the calibration value of the internal current gain of the metering chip is 0, the current load current is judged to belong to which current section according to the original current value detected by the ammeter in real time, and then the real-time current gain is calculated according to the calibration formula of the corresponding current section. And then writing the calculated current gain into a metering chip to obtain accurate metering of the current. Accurate metering of the current means that the current value calculated by the ammeter is close to the current value output by the standard source, which is also the purpose of calibration. Because of the errors of the peripheral circuits and the devices, the standard source outputs a standard current/voltage to the direct current meter under the condition of no calibration, and a relatively large error exists between the current/voltage calculated by the direct current meter and the standard value, so that the calculated value of the direct current meter needs to be corrected through calibration, the current/voltage calculated by the direct current meter is close to the standard value, and the error is met. According to the calibration method, in the actual tool calibration process, the calibration work can be realized only by testing the ammeter current reading value and the standard current value of each sectional point.
It will be appreciated that instead of dividing the gain curve into a plurality of line segments, dynamic calibration may be achieved by polynomial or other fitting of the curve. For example, some modeling approaches to establish input and output relationships, such as neural networks, etc. Taking a neural network as an example, a model fitting curve can be established by introducing input and output data samples through some simulation tools.
In addition, when the ammeter is connected with forward current and reverse current respectively, the sampling voltage from the circuit to the metering chip end may not be completely consistent, so that the gain calibration curves of the forward current and the reverse current may not be completely consistent, and the same set of calibration formulas cannot be used, and therefore, the forward current and the reverse current can be calibrated separately to obtain two calibration curves, namely two sets of calibration formulas.
According to the method, the current gain curve in the whole working range is obtained, the current gain curve is approximately divided into a plurality of linear calibration interval sections, the gain value is calculated in real time according to the corresponding calibration interval section through the current value detected in real time, the problem that the electric meter cannot be accurately calibrated in a single-point calibration mode to achieve the required precision level due to nonlinearity of components is solved, and the precision of the electric meter can be improved in the whole working range.
According to the electric energy meter calibration method, after the standard currents of different grades output by the standard source are received, the real-time current corresponding to the standard currents is obtained, then gain data are obtained according to the standard currents and the real-time currents, calibration parameters are obtained based on a gain curve, and therefore calibration can be carried out according to the calibration parameters. According to the method, gain data and calibration parameters are obtained based on a plurality of standard currents and a plurality of real-time currents, and the current values detected by the electric energy meter are calibrated according to the calibration parameters, so that the current calibration in a large range can be realized, the problem that the calibration result is inaccurate after single-point calibration due to nonlinearity of components is solved, the influence of nonlinearity of the components on the calibration is reduced, the accuracy of the calibration result is improved, and the accuracy of the electric energy meter can be improved in a large working range, so that the use reliability of the electric energy meter is improved.
In one embodiment, an electric energy meter calibration device is provided, which comprises a sampling circuit and a processor, wherein the sampling circuit is used for receiving standard currents of different grades output by a standard source, acquiring real-time currents corresponding to the standard currents, the real-time currents are current reading values of the electric energy meter after the electric energy meter receives the standard currents, and the processor is used for calibrating the electric energy meter according to the method. The processor may include a metering chip and an MCU, and FIG. 8 is a schematic diagram of the operation of the power meter calibration device.
According to the electric energy meter calibration device, after the standard currents of different grades output by the standard source are received, the real-time currents corresponding to the standard currents are obtained, then gain data are obtained according to the standard currents and the real-time currents, calibration parameters are obtained based on a gain curve, and therefore calibration can be carried out according to the calibration parameters. According to the method, gain data and calibration parameters are obtained based on a plurality of standard currents and a plurality of real-time currents, and the current values detected by the electric energy meter are calibrated according to the calibration parameters, so that the current calibration in a large range can be realized, the problem that the calibration result is inaccurate after single-point calibration due to nonlinearity of components is solved, the influence of nonlinearity of the components on the calibration is reduced, the accuracy of the calibration result is improved, and the accuracy of the electric energy meter can be improved in a large working range, so that the use reliability of the electric energy meter is improved.
In one embodiment, an electric energy meter is provided, comprising an electric energy meter calibration device as described above.
According to the electric energy meter, after receiving standard currents of different grades output by the standard source, real-time currents corresponding to the standard currents are obtained, gain data are obtained according to the standard currents and the real-time currents, calibration parameters are obtained based on a gain curve, and therefore calibration can be carried out according to the calibration parameters. According to the method, gain data and calibration parameters are obtained based on a plurality of standard currents and a plurality of real-time currents, and the current values detected by the electric energy meter are calibrated according to the calibration parameters, so that the current calibration in a large range can be realized, the problem that the calibration result is inaccurate after single-point calibration due to nonlinearity of components is solved, the influence of nonlinearity of the components on the calibration is reduced, the accuracy of the calibration result is improved, and the accuracy of the electric energy meter can be improved in a large working range, so that the use reliability of the electric energy meter is improved.
In one embodiment, a power meter system is provided that includes a standard source and a power meter as described above.
According to the electric energy meter system, after receiving standard currents of different grades output by the standard source, real-time currents corresponding to the standard currents are obtained, gain data are obtained according to the standard currents and the real-time currents, calibration parameters are obtained based on a gain curve, and therefore calibration can be carried out according to the calibration parameters. According to the method, gain data and calibration parameters are obtained based on a plurality of standard currents and a plurality of real-time currents, and the current values detected by the electric energy meter are calibrated according to the calibration parameters, so that the current calibration in a large range can be realized, the problem that the calibration result is inaccurate after single-point calibration due to nonlinearity of components is solved, the influence of nonlinearity of the components on the calibration is reduced, the accuracy of the calibration result is improved, and the accuracy of the electric energy meter can be improved in a large working range, so that the use reliability of the electric energy meter is improved.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.
Claims (11)
1. The electric energy meter calibration method is characterized by comprising the following steps of:
receiving standard currents of different grades output by a standard source;
acquiring a real-time current corresponding to the standard current; the real-time current is a current reading value of the electric energy meter after receiving the standard current;
gain data are obtained according to the standard current and the real-time current;
obtaining calibration parameters based on the gain data; the calibration parameters are used for calibrating the electric energy meter;
the gain data includes a gain curve, and the gain data obtained according to the standard current and the real-time current includes:
taking the ratio of the standard current to the corresponding real-time current as a current gain value;
drawing a curve according to the zero offset value and the current gain value corresponding to each real-time current, and taking the curve as a gain curve; the zero offset value is a current reading value of the electric energy meter when the standard source outputs 0 ampere of current; when the gain curve is drawn, the zero offset value is eliminated, and then gain calibration is carried out, so that the gain curve is obtained as a curve with the zero offset value eliminated.
2. The method of calibrating an electric energy meter according to claim 1, wherein an abscissa of the gain curve is each current value, and an ordinate of the gain curve is a gain value corresponding to each current value.
3. The method of calibrating a power meter according to claim 1, wherein said deriving calibration parameters based on said gain data comprises:
dividing the real-time current into different current intervals, and obtaining calibration parameters corresponding to the different current intervals based on the gain data.
4. The method for calibrating an electric energy meter according to claim 3, wherein the dividing the real-time current into different current intervals, and obtaining calibration parameters corresponding to the different current intervals based on the gain data, comprises:
and carrying out linear calculation on the end point value of each current interval and the current gain value corresponding to each end point value, and taking the obtained linear calibration parameter as the calibration parameter corresponding to different current intervals.
5. The method of calibrating a power meter according to claim 1, further comprising, after obtaining the calibration parameters based on the gain data:
and calibrating the current value detected by the electric energy meter according to the calibration parameter to obtain an accurate measurement value of the electric energy meter.
6. The method for calibrating an electric energy meter according to claim 5, wherein the calibrating the current value detected by the electric energy meter according to the calibration parameter to obtain an accurate measurement value of the electric energy meter comprises:
calculating to obtain real-time current gain according to the calibration parameters and the current value detected by the electric energy meter;
and obtaining an accurate metering value of the electric energy meter according to the current value detected by the electric energy meter and the real-time current gain.
7. The method for calibrating an electric energy meter according to claim 6, wherein the calculating the real-time current gain according to the calibration parameter and the current value detected by the electric energy meter comprises:
acquiring a current interval in which a current value detected by an electric energy meter is located;
and calculating to obtain the real-time current gain according to the calibration parameters corresponding to the current interval in which the current value detected by the electric energy meter is located.
8. The method for calibrating an electric energy meter according to any of claims 1-7, further comprising, after obtaining calibration parameters based on the gain data:
when receiving the current in the opposite direction, returning to the receiving standard current of different grades output by the standard source.
9. The electric energy meter calibration device is characterized by comprising a sampling circuit and a processor, wherein the sampling circuit is used for receiving standard currents of different grades output by a standard source, acquiring real-time currents corresponding to the standard currents, the real-time currents are current reading values of the electric energy meter after the electric energy meter receives the standard currents, and the processor is used for calibrating the electric energy meter according to the method of any one of claims 1-8.
10. An electric energy meter comprising an electric energy meter calibration device according to claim 9.
11. A power meter system comprising a standard source and the power meter of claim 10.
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| CN114813521B (en) * | 2022-04-28 | 2022-10-28 | 深圳市帝迈生物技术有限公司 | Gain calibration method and system, and related device |
| CN115993568B (en) * | 2023-03-24 | 2023-05-30 | 绅克半导体科技(苏州)有限公司 | Semiconductor tester and direct current calibration method for test channel of semiconductor tester |
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