CN112946560A - 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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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 standard currents of different levels output by a standard source are received, 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 conducted according to the calibration parameters. The method obtains the gain data and the calibration parameters based on the plurality of standard currents and the plurality of real-time currents, calibrates the current value detected by the electric energy meter according to the calibration parameters, can realize current calibration in a large range, solves the problem that the calibration result is inaccurate after single-point calibration is used due to nonlinearity of components, reduces the influence of the nonlinearity of the components on the calibration, improves the accuracy of the calibration result, can improve the precision of the electric energy meter in a large working range, and accordingly improves the use reliability of the electric energy meter.
Description
Technical Field
The present application relates to the field of electric energy meter technologies, and in particular, to a method and an apparatus for calibrating an electric energy meter, and an electric energy meter system.
Background
The electric energy meter is an instrument for measuring electric energy, is also called an electric meter, a fire meter, a kilowatt hour meter and the like, is widely applied to households or other occasions, can be used for measuring and counting the used electric energy and is convenient for monitoring the electricity utilization 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 self errors of the peripheral circuit and the sampling component are corrected.
The conventional method for calibrating the electric energy meter comprises a single-point calibration method, namely, a fixed current point is selected in the whole measuring range, and the current in the whole measuring range is calibrated by using the calibration value of the current point. However, since the direct current electric energy meter usually adopts the hall sensor or the manganin as a current sampling element, and the hall sensor and the manganin have nonlinearity, and other elements having nonlinearity may exist on the circuit, the calibration within a large working range cannot be realized by using a single-point calibration mode in the calibration process, and the calibration result is inaccurate and the use is unreliable.
Disclosure of Invention
The invention provides a method and a device for calibrating an electric energy meter, the electric energy meter and an electric energy meter system, aiming at the problem that the traditional method for calibrating the electric energy meter is unreliable in use.
An electric energy meter calibration method comprises the following steps:
receiving standard currents of different grades output by a standard source;
acquiring real-time current corresponding to the standard current; the real-time current is a current reading value of the electric energy meter after the standard current is received;
obtaining gain data 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 electric energy meter calibration device 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 and 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.
An electric energy meter comprises the electric energy meter calibration device.
An electric energy meter system comprises 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 the standard currents of different levels output by the standard source are received, the real-time current corresponding to the standard currents is obtained, then the gain data is obtained according to the standard currents and the real-time current, the calibration parameters are obtained based on the gain data, and therefore calibration can be carried out according to the calibration parameters. The method obtains the gain data and the calibration parameters based on the plurality of standard currents and the plurality of real-time currents, calibrates the current value detected by the electric energy meter according to the calibration parameters, can realize current calibration in a large range, solves the problem that the calibration result is inaccurate after single-point calibration is used due to nonlinearity of components, reduces the influence of the nonlinearity of the components on the calibration, improves the accuracy of the calibration result, can improve the precision of the electric energy meter in a large working range, and accordingly improves the use reliability of the electric energy meter.
In one embodiment, the gain data comprises a gain curve, and the obtaining the gain data according to the standard current and the real-time current comprises:
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 to be used as a gain curve; the zero offset value is a current reading value of the electric energy meter when the standard source outputs 0A current.
In one embodiment, the obtaining the calibration parameter based on the gain data includes:
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.
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 performing linear calculation on the endpoint values of the current intervals and the current gain values corresponding to the endpoint values, and taking the obtained linear calibration parameters as calibration parameters 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 the accurate metering 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 metering 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 a 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 the electric energy meter is located;
and calculating to obtain the real-time current gain according to the calibration parameters corresponding to the current interval where 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 metering 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 metering value of the electric energy meter according to the calibrated current value and the zero offset value; the zero offset value is a current reading value of the electric energy meter when the standard source outputs 0A 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 standard current of different levels output by the receiving standard source.
Drawings
FIG. 1 is a flow diagram of a method for calibrating an electric energy meter according to one embodiment;
FIG. 2 is a flow chart of a method for calibrating an electric energy meter in another embodiment;
FIG. 3 is a flow chart of a method for calibrating an electric energy meter in another embodiment;
FIG. 4 is a flow chart of a method for calibrating an electric energy meter in yet another embodiment;
FIG. 5 is a flow chart of a method for calibrating an electric energy meter in yet another embodiment;
FIG. 6 is a schematic diagram of the connection of an electric energy meter to a standard source in one embodiment;
FIG. 7 is a graph of gain curves calculated in one embodiment;
FIG. 8 is a schematic diagram of the operation of an embodiment of the calibration apparatus for an electric energy meter;
FIG. 9 is a schematic diagram illustrating a process for calibrating an electric energy meter according to an embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described more fully below by way of examples in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present 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 manganin and the like. The method can be executed by an independent calibration device independent of the electric energy meter to calibrate the electric energy meter, and can also be realized by a calibration device built in the electric energy meter, so that the hardware cost is saved, and the utilization rate of devices is improved. In this embodiment, an example of calibrating an electric energy meter by using a calibration device built in the electric energy meter is described, where 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 data sampled by the sampling circuit. Referring to fig. 1, the calibration method of the electric energy meter includes the following steps:
step S100: different levels of standard current output by the standard source are received.
Specifically, different levels of standard currents output by the standard source can be received by the sampling circuit, and the received standard currents are transmitted 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 of different levels 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 the electric energy meter receives the standard current. After the standard current reaches the electric energy meter, the standard current reaches a metering chip of the ammeter through some circuits or devices in the ammeter, and the metering chip generates a current reading value after processing. Because devices inside the electric energy meter or peripheral circuits may have errors, the reading value of the current generated after passing through the devices is different from the actual current received by the electric energy meter before passing through the devices, so that the reading value of the ammeter is inaccurate. Therefore, 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 used in cooperation with other devices, for example, when the processor in the calibration device is an MCU, the metering chip is used in cooperation with the MCU, and the metering chip is specially responsible for metering, and the MCU is responsible for processing other data. In an expanded way, the processor in the calibration device can comprise an ADC and an MCU, and the work of metering and data processing is completed by the MCU through a software algorithm.
Step S500: gain data is obtained according to 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, and for example, the gain data may be a gain curve, where each current value is taken as an abscissa, and a gain value corresponding to each current value is taken as an ordinate, and the gain curve is drawn, and the gain curve may reflect a change condition of the gain value in the whole operating current range, so as to reflect a change condition of the error magnitude of the electric energy meter in the whole operating 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, as long as one current value type is adopted for the whole abscissa. 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.
And the calibration parameters are used for calibrating the electric energy meter. After the gain data is obtained, calibration parameters may be obtained based on the gain data. The application mode of the calibration parameter is not unique, for example, the calibration parameter is combined with different formula models to obtain the calibration formula, the method for obtaining the calibration formula is not unique, a relatively close formula model can be selected according to the shape of the gain curve, and the values of the standard current and the real-time current are substituted into the formula model to obtain the calibration formula applicable in the full current range or the partial current range.
In one embodiment, the gain data includes a gain curve, see fig. 3, and step S500 includes step S510 and step S520.
Step S510: and taking the ratio of the standard current and the corresponding real-time current as a 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 difference between the standard current and the corresponding real-time current can be accurately reflected by the ratio. It is understood that in other embodiments, the current gain value may be a difference between the standard current and the corresponding real-time current, etc., as long as the skilled person realizes the current gain value.
Step S520: and drawing a curve as a gain curve according to the zero offset value and the current gain value corresponding to each real-time current.
The zero offset value is a current reading value of the electric energy meter when the standard source outputs 0A 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 that the change condition of the error size of the electric energy meter in the whole working current range is reflected. 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 the real-time current value, the gain curve can reflect the change condition of the gain value in the whole real-time current range, and calibration in the whole working range can be realized on the basis, so that the precision of the electric energy meter is improved in the whole working range.
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 and the data corresponding to the abscissa of the gain curve is the 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 a case that the gain curve corresponds to different curve characteristics in different real-time current ranges. At this moment, the real-time current is divided into different current intervals, then gain curves in the different current intervals are analyzed respectively, calibration parameters corresponding to the different current intervals are obtained, calibration requirements under more conditions can be met, the obtained calibration formula is more suitable for actual conditions, and therefore accuracy of the calibration formula is improved.
In one embodiment, referring to fig. 4, step S710 includes step S712.
Step S712: and performing linear calculation on the endpoint values of the current intervals and the current gain values corresponding to the endpoint values, and taking the obtained linear calibration parameters as calibration parameters corresponding to different current intervals.
The method for obtaining the calibration parameters is different according to different characteristics of the gain curves in each current interval. In this embodiment, when the gain curve in each current interval is approximately linearly changed, the endpoint values of each current interval and the current gain values corresponding to the endpoint values may be linearly calculated, and the obtained linear calibration parameters are 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 segment are taken for linear calculation, and if the a0(x0, y0) point and the a1(x1, y1) point are known, the gain value of any point a (x, y) between the two points is:
y＝(y1-y0)/(x1-x0)*(x-x0)+y0
the formula is a linear calibration formula in the corresponding current interval, wherein the fixed value parameter is a linear calibration parameter. Further, the obtained linear calibration parameters and linear calibration formulas corresponding to the current intervals are stored in a memory. When the electric energy meter is electrified every time, the linear calibration parameters and the linear calibration formula corresponding to each current section are obtained from the memory, and then calibration is carried out according to the linear calibration parameters or the linear calibration formula.
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 current gain curve measured by the electric meter is illustrated, and based on the current gain curve, the whole current gain curve can be divided into seven segments, wherein the first segment is: 30A-10A, second stage: 10A-5A, third stage: 5A-3A, fourth stage: 3A-1.5A, fifth stage: 1.5A-1.0A, sixth stage: 1.0A-0.5A, seventh stage: 0.5A-0.3A, considering that the gain curve is approximately linear in each section, the end point values of each current interval and the current gain values corresponding to the end point values can be linearly calculated, and the obtained linear calibration formula is used as the calibration formula corresponding to different current intervals. It is understood that in other embodiments, the different current intervals may be divided according to other criteria, as long as the implementation is considered by those skilled in the art.
In an embodiment, referring to fig. 2, after step S700, the method for calibrating a power meter further includes step S900.
Step S900: and calibrating the current value detected by the electric energy meter according to the calibration parameters to obtain the 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 the parameters, when 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 accurate metering value of the electric energy meter is obtained by combining the type of the current calibration value and the current value detected by the ammeter. Specifically, the manner of obtaining the accurate metering value of the electric energy meter is not unique according to the type of the calibrated current calibration value, for example, when the calibrated current calibration value is a current difference value, the sum or the product of the current value detected by the ammeter and the calibrated current calibration value may be used as the calibrated current calibration value. The type of the calibration formula and the type of the calibrated current calibration value may be other types, and the manner of calculating the accurate metering value of the electric energy meter may be adjusted accordingly, as long as the calculation can be realized by those 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 number of the electric energy meter to be displayed, so that a user can obtain 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 meter is close to the current value output by the standard source, which is also the purpose of calibration. Due to errors of the peripheral circuit and the device, 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 a standard value, so that the calculation value of the electric energy meter can be corrected by the electric energy meter calibration method provided by the application, the current/voltage calculated by the electric energy meter is close to the standard value, and the precision 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 the current value, the real-time current gain can be calculated according to the calibration parameter 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 metering 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. According to different types of real-time current gain, the mode of obtaining the accurate metering value of the electric energy meter is different. 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 the accurate metering value of the electric energy meter, and when the real-time current gain is a difference, the sum of the current value detected by the ammeter and the real-time current gain can be used as the accurate metering value of the electric energy meter. The accurate measurement of the current is that the current value calculated by the electric meter is close to the current value output by the standard source, which is also the aim of calibration. Due to errors of the peripheral circuit and the device, 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 a standard value, so that the calculation value of the electric energy meter can be corrected by the electric energy meter calibration method provided by the application, the current/voltage calculated by the electric energy meter is close to the standard value, and the precision 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 located.
Specifically, the calibration formula may include different calibration formulas corresponding to different current intervals, and in the actual use process of the electric energy meter, after the electric energy meter detects the 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 where 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 calculated 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 detected currents are matched with different calibration formulas, and the accuracy of a calibration result is improved.
In one embodiment, after step S700, the calibration method of the electric energy meter further includes step 800.
Step 800: when a current in the opposite direction is received, the process returns to step S100.
Specifically, the currents in opposite directions mean that the directions of the currents are different. When the included angle between the voltage and the current is 0 degrees, 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. Errors caused by different directions of current passing through components on the electric meter may be different, and due to asymmetry of component characteristics, forward and reverse currents may need to be calibrated separately. Taking fig. 6 as an example, the current of the standard source is output from I +, flows through the power meter from output-to input-and from I-back to the standard source. The measured power will be a positive value and the current will be a positive current. But 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 energy meter from input-to output-, and back from I-to the standard source. The measured power 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 respectively connected with forward current and reverse current, the sampling voltage or sampling current from the sampling circuit to the metering chip end may not be completely consistent, and therefore, the gain calibration curves of the forward current and the reverse current may not be completely consistent. When the current in the opposite direction is received, the procedure returns to the step S100, the calibration is performed again, the forward and reverse currents can be separately calibrated, two calibration curves, namely two sets of calibration formulas, are obtained, and the calibration requirements 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, the following detailed description is given in conjunction with a specific embodiment. In one embodiment, the electric energy meter is a direct current meter, and the electric energy meter calibration method comprises the following steps: first, when the standard source outputs 0A, a reading I0 of the dc meter is read, and this value is used as a zero offset value I _ offset of the dc meter, I0. The standard source is an instrument that can output voltage and current with high accuracy and stability. The function to be realized is that the standard source outputs standard voltage and standard current of different grades to the DC meter, and the DC meter is calibrated according to the standard value. When the standard source is used to output currents of different levels to the direct current meter under the condition that the gain calibration is not carried out, the current reading value of the direct current meter is obtained, the current reading value I of the direct current meter and the standard source output value I' are calculated, and the current gain value IRMSgain at each current point is obtained. The calculated current gain values at each current point are plotted as a curve, and the results are shown in the figure. As can be seen, the current gain changes rapidly and nonlinearly at a small current.
And (3) approximately dividing the current gain curve into a plurality of linear line segments according to the current value according to the requirement, and taking calibration values of end points at two ends of the line segments to perform linear calculation. Referring to fig. 7, the entire current gain curve can be divided into seven segments, the first segment: 30A-10A, second stage: 10A-5A, third stage: 5A-3A, fourth stage: 3A-1.5A, fifth stage: 1.5A-1.0A, sixth stage: 1.0A-0.5A, seventh stage: 0.5A-0.3A, considering that the gain curve is approximately linear in each section, the endpoint values of each current interval and the current gain values corresponding to the endpoint values can be linearly calculated. As known from points a0(x0, y0) and a1(x1, y1), the gain value of any point a (x, y) between the two points is:
y＝(y1-y0)/(x1-x0)*(x-x0)+y0
and storing the obtained plurality of linear calibration formulas into a memory. And when the electric meter is electrified every time, the calibration formula parameters of the calculated gain of each current section are obtained from the memory.
In the actual use process of the electric meter, please refer to fig. 9, when power-on initialization is performed, the current gain calibration value inside the metering chip is 0, which current segment interval the current load current belongs to is determined according to the original current value detected by the electric meter in real time, and then the real-time current gain is calculated according to the calibration formula of the corresponding current segment interval. And then writing the calculated current gain into a metering chip to obtain accurate metering of the current. Accurate metering of current means that the current value calculated by the meter is close to the current value output by the standard source, which is also the purpose of calibration. Due to 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 a 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 segmentation point.
It will be appreciated that dynamic calibration may also be achieved for the gain curve without dividing it into a plurality of line segments, but by fitting the curve in a polynomial or other manner. For example, some modeling approaches to establish input and output relationships, such as neural networks, etc. Taking a neural network as an example, the model fitting curve can be established by importing input and output data samples through some simulation tools.
In addition, when the electric meter is respectively connected with forward current and reverse current, the sampling voltage from the circuit to the measuring chip end is possibly not completely consistent, so that the gain calibration curves of the forward current and the reverse current are possibly not completely consistent, the same set of calibration formula 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.
The method approximately divides the current gain curve into a plurality of linear calibration sections by obtaining the current gain curve in the whole working range, calculates the gain value in real time according to the corresponding calibration section through the current value detected in real time, solves the problem that the ammeter can not be accurately calibrated to reach the required precision grade by using a single-point calibration mode due to the nonlinearity of components, and can improve the precision of the ammeter in the whole working range.
According to the electric energy meter calibration method, after the standard currents of different levels 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 the gain curves, and therefore calibration can be carried out according to the calibration parameters. The method obtains the gain data and the calibration parameters based on the plurality of standard currents and the plurality of real-time currents, calibrates the current value detected by the electric energy meter according to the calibration parameters, can realize current calibration in a large range, solves the problem that the calibration result is inaccurate after single-point calibration is used due to nonlinearity of components, reduces the influence of the nonlinearity of the components on the calibration, improves the accuracy of the calibration result, can improve the precision of the electric energy meter in a large working range, and accordingly improves the use reliability of the electric energy meter.
In one embodiment, an electric energy meter calibration device is provided, which includes a sampling circuit and a processor, wherein the sampling circuit is configured to receive standard currents of different levels output by a standard source, and obtain a real-time current corresponding to the standard current, the real-time current is a current reading value of an electric energy meter after the electric energy meter receives the standard current, and the processor is configured to perform electric energy meter calibration according to the method. The processor can comprise a metering chip and an MCU, and FIG. 8 is an operation schematic diagram of the electric energy meter calibration device.
According to the electric energy meter calibration device, after the standard currents of different levels 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 the gain curves, and therefore calibration can be carried out according to the calibration parameters. The method obtains the gain data and the calibration parameters based on the plurality of standard currents and the plurality of real-time currents, calibrates the current value detected by the electric energy meter according to the calibration parameters, can realize current calibration in a large range, solves the problem that the calibration result is inaccurate after single-point calibration is used due to nonlinearity of components, reduces the influence of the nonlinearity of the components on the calibration, improves the accuracy of the calibration result, can improve the precision of the electric energy meter in a large working range, and accordingly improves the use reliability of the electric energy meter.
In one embodiment, an electric energy meter is provided, comprising the electric energy meter calibration device as described above.
The electric energy meter obtains the real-time current corresponding to the standard current after receiving the standard currents of different levels output by the standard source, then obtains the gain data according to the standard current and the real-time current, and obtains the calibration parameters based on the gain curve, so that the calibration can be carried out according to the calibration parameters. The method obtains the gain data and the calibration parameters based on the plurality of standard currents and the plurality of real-time currents, calibrates the current value detected by the electric energy meter according to the calibration parameters, can realize current calibration in a large range, solves the problem that the calibration result is inaccurate after single-point calibration is used due to nonlinearity of components, reduces the influence of the nonlinearity of the components on the calibration, improves the accuracy of the calibration result, can improve the precision of the electric energy meter in a large working range, and accordingly improves the use reliability of the electric energy meter.
In one embodiment, an electric energy meter system is provided comprising a standard source and an electric energy meter as described above.
According to the electric energy meter system, after the standard currents of different levels 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, and calibration parameters are obtained based on the gain curves, so that calibration can be carried out according to the calibration parameters. The method obtains the gain data and the calibration parameters based on the plurality of standard currents and the plurality of real-time currents, calibrates the current value detected by the electric energy meter according to the calibration parameters, can realize current calibration in a large range, solves the problem that the calibration result is inaccurate after single-point calibration is used due to nonlinearity of components, reduces the influence of the nonlinearity of the components on the calibration, improves the accuracy of the calibration result, can improve the precision of the electric energy meter in a large working range, and accordingly improves the use reliability of the electric energy meter.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (11)
1. A method for calibrating an electric energy meter is characterized by comprising the following steps:
receiving standard currents of different grades output by a standard source;
acquiring real-time current corresponding to the standard current; the real-time current is a current reading value of the electric energy meter after the standard current is received;
obtaining gain data 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.
2. The method of claim 1, wherein the gain data comprises a gain curve, and wherein the obtaining gain data based on the standard current and the real-time current comprises:
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 to be used as a gain curve; the zero offset value is a current reading value of the electric energy meter when the standard source outputs 0A current.
3. The method of claim 2, wherein the deriving calibration parameters based on the gain data comprises:
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.
4. The electric energy meter calibration method 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 performing linear calculation on the endpoint values of the current intervals and the current gain values corresponding to the endpoint values, and taking the obtained linear calibration parameters as calibration parameters corresponding to different current intervals.
5. The method of claim 1, wherein after obtaining the calibration parameter based on the gain data, the method further comprises:
and calibrating the current value detected by the electric energy meter according to the calibration parameter to obtain the accurate metering value of the electric energy meter.
6. The electric energy meter calibration method 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 metering 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 a 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 the electric energy meter is located;
and calculating to obtain the real-time current gain according to the calibration parameters corresponding to the current interval where the current value detected by the electric energy meter is located.
8. The method for calibrating an electric energy meter according to any one of claims 1 to 7, wherein after obtaining the calibration parameter based on the gain data, the method further comprises:
when receiving the current in the opposite direction, returning to the standard current of different levels output by the receiving standard source.
9. An 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 and acquiring real-time currents corresponding to the standard currents, the real-time currents are current readings of an 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 to 8.
10. An electric energy meter, characterized by comprising the electric energy meter calibration device according to claim 9.
11. An electric energy meter system comprising a standard source and the electric energy meter of claim 10.
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