Energy metering method for electric energy meter based on multi-slope integration adc and dynamic error compensation

Abstract

The present application relates to the technical field of electric energy metering, and more particularly to an electric energy metering method for electric energy meters based on a multi-slope integration ADC and dynamic error compensation. The method comprises the following steps: obtaining an original analog signal, performing analog-digital conversion processing on the original analog signal to obtain a digital signal, establishing a local observation window during the analog-digital conversion processing, and calculating a non-linear error index; based on the non-linear error index, using a time reversal recursive reconstruction compensation algorithm to obtain a compensated digital signal; and performing calculation and analysis on the compensated digital signal to obtain a metering result. The method solves the problems of insufficient sampling precision, unstable metering precision, and low metering precision.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric energy metering, and in particular to an electric energy metering method for electric energy meters based on a multi-slope integrating ADC and dynamic error compensation. BACKGROUND

[0002] Electric energy meters usually use analog-to-digital conversion (ADC) technology to convert analog signals such as voltage, current, etc. into digital signals, so as to calculate and monitor electric energy. Traditional ADC technology is susceptible to noise and quantization errors when converting low-frequency signals, resulting in low conversion accuracy, especially in complex environments such as temperature fluctuations, power fluctuations, etc. It is easy to produce large measurement errors. Therefore, how to improve the accuracy and stability of electric energy meters has always been a research hotspot in the field of electric energy metering.

[0003] Multi-slope integrating ADC (MSI ADC) is a digital conversion method that approximates the original analog signal by step-by-step integration. Compared with traditional single-slope ADC, MSI ADC can accumulate signal information step by step over multiple integration periods, thereby effectively improving the conversion accuracy of the signal, especially in the processing of low-frequency signals. However, MSI ADC technology still has some problems, especially in the dynamic error compensation of signals. Since electric energy meters often operate in complex environments, external disturbances such as temperature changes and power fluctuations will cause the system to deviate, and traditional error compensation methods are often difficult to adapt to such dynamic changes, thereby affecting the accuracy and stability of the system. SUMMARY

[0004] The present application provides an electric energy metering method for electric energy meters based on a multi-slope integrating ADC and dynamic error compensation to solve the problems of insufficient sampling accuracy, unstable metering accuracy, and low metering accuracy.

[0005] The electric energy metering method for electric energy meters based on a multi-slope integrating ADC and dynamic error compensation of the present application comprises the following steps:

[0006] S1. Obtain the original analog signal, perform analog-to-digital conversion processing on the original analog signal to obtain a digital signal, and at the same time, establish a local observation window in the analog-to-digital conversion processing to calculate a non-linear error index;

[0007] S2. Based on the non-linear error index, use a time reversal recursive reconstruction compensation algorithm to obtain a compensated digital signal; and perform calculation and analysis on the compensated digital signal to obtain a metering result.

[0008] Preferably, the S1 specifically comprises:

[0009] The original analog signal is converted into a digital signal by using a multi-slope integration analog-digital conversion.

[0010] Preferably, S1 specifically includes:

[0011] A nonlinear difference index function is introduced, and the nonlinear error index is obtained by calculating the deviation degree of the digital signals at the relative symmetric positions in the local observation window under the nonlinear measurement.

[0012] Preferably, S2 specifically includes:

[0013] In the implementation process of the time reversal recursive reconstruction compensation algorithm, a time reversal mapping structure is constructed, the digital signals in the local observation window are mirror transformed to generate the reversed digital signals.

[0014] Preferably, S2 specifically includes:

[0015] Based on the reversed digital signals, the inversion error intensity is generated by the time reversal error compensation algorithm.

[0016] Preferably, S2 specifically includes:

[0017] In the implementation process of the time reversal error compensation algorithm, the inversion structure error mapping function is defined to describe the asymmetric degree between the reversed digital signals.

[0018] Preferably, S2 specifically includes:

[0019] Based on the inversion error intensity, the third-order tensor structure is constructed to calculate the coupling error deviation.

[0020] Preferably, S2 specifically includes:

[0021] Based on the coupling error deviation, the nonlinear error index and the inversion error intensity, the correction amount feedback is constructed to generate the compensated digital signals.

[0022] Preferably, S2 specifically includes:

[0023] After each feedback, it is determined whether the current output compensated digital signals are located in the preset stable reference domain, if yes, the compensation is completed; otherwise, it is necessary to back up and reevaluate the coupling error deviation until the compensated digital signals are located in the stable reference domain.

[0024] The technical scheme of the present application has the following advantages:

[0025] 1. The use of a multi-slope integration circuit and multi-slope integration analog-to-digital conversion technology effectively improves the digitization accuracy of the original analog signal. This significantly reduces the impact of quantization error and noise, especially for low-frequency signal processing, and increases the sampling rate. Multiple integration processes and gradual adjustment of the slope period ensure high sensitivity and accuracy to subtle changes, significantly improving measurement accuracy.

[0026] 2. The introduction of local observation windows and nonlinear error indicators enhances the ability to respond to complex error patterns, allowing error correction to more precisely adapt to various dynamically changing environments, such as temperature fluctuations and power supply fluctuations, thereby ensuring the stability and long-term accuracy of metering results. A third-order tensor structure is used to analyze the coupling patterns between multidimensional errors. By capturing the error characteristics of the electricity meter at different slope periods and signal dimensions, it can more comprehensively correct the digital signal and identify potential complex error patterns in the signal (such as non-periodic mutations and signal amplitude mutations). By constructing correction feedback, precise multidimensional error analysis and compensation are achieved, greatly improving the compensation effect.

[0027] 3. A feedback mechanism is used to ensure signal correction stability during the compensation process through dynamic adjustment of error compensation. During the compensation process, a correction closed loop based on real-time feedback is formed by combining nonlinear error indicators and inversion error strength, ensuring that the digital signal can be accurately restored to the expected value after each compensation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a flow chart of the electric energy metering method based on multi-slope integral ADC and dynamic error compensation according to the present invention;

[0029] Figure 2 The figure is a simplified circuit diagram of a multi-slope integral analog-to-digital conversion in the prior art. DETAILED DESCRIPTION

[0030] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0031] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0032] The application provides a power metering method based on a multi-slope integrating ADC and dynamic error compensation.

[0033] Referring to the drawings Figure 1 , a flowchart of a power metering method based on a multi-slope integrating ADC and dynamic error compensation is shown, and the method comprises the following steps:

[0034] S1. Obtain an original analog signal, and perform analog-digital conversion on the original analog signal to obtain a digital signal. At the same time, a local observation window is established during the analog-digital conversion, and a non-linear error index is calculated.

[0035] An original analog signal is obtained from a power meter, and the original analog signal is subjected to analog-digital conversion by a multi-slope integrating ADC (MSI ADC) to obtain a digital signal. A simplified circuit diagram of the multi-slope integrating ADC can be referred to FIG. 1. Figure 2 , wherein, is an input voltage (input signal), and are reference voltages; is an injection resistor; is a switch; is an integrator; is an integration capacitor.

[0036] The multi-slope integrating ADC is a digital conversion method that approximates the original analog signal by step-by-step integration. In the multi-slope integrating ADC process, the conversion accuracy of the original analog signal is improved by repeatedly integrating in N (for example, 6) slope periods set according to specific requirements. The slope period in the multi-slope integrating ADC refers to the period during which the integration rate (slope) of the signal remains unchanged during each integration process. In each slope period, the charge accumulation of the original analog signal is calculated step by step, and at the end of each period, the slope is switched according to the threshold value after comparing the charge accumulation with the preset ideal reference value, and integration or comparison is performed. Both the ideal reference value and the threshold value are set according to expert experience. During the analog-digital conversion process, the changes in the original analog signal are integrated multiple times, and the effects of noise and quantization errors are reduced through continuous adjustment of the slope period, and finally a digital signal such as voltage, current, power, etc. is obtained. The technical advantage of the multi-slope integrating ADC is that it is particularly accurate in processing low-frequency signals, can greatly improve the conversion accuracy and dynamic range, and reduce the quantization error commonly seen in traditional analog-digital conversion.

[0037] In the multi-slope integrating ADC process, the sampling output sequence in the first slope period is , which is a digital signal, is expressed as the digital signal of the th class after the th slope period processing, wherein, is the total number of classes of the digital signal; a local observation window is established, which is defined as the values of the digital signal at the time points before and after the current time , , , , The value is determined according to actual requirements; the local observation window is expressed as follows:

[0038]

[0039] wherein, is the local observation window, which is the set of all digital signals near the time , is the digital signal of the th class after the th slope period processing at the time , is the digital signal of the th class after the th slope period processing at the time .

[0040] Further, a nonlinear difference index function is introduced, which evaluates the nonlinear fluctuation of the error in the current local observation window by calculating the offset degree of the digital signals at the relatively symmetrical positions in the current local observation window under the nonlinear measurement, and the specific expression is as follows:

[0041]

[0042] wherein, is the nonlinear error index of the digital signal of the th class after the th slope period processing at the time ; The square root term is used to compress the amplitude amplitude to avoid the local maximum value dominating the mean square deviation calculation; the logarithmic terms and are used to enhance the response ability to small disturbances.

[0043] S2. Based on the nonlinear error index, a time reversal recursive reconstruction compensation algorithm is used to obtain the compensated digital signal; the compensated digital signal is calculated and analyzed to obtain the measurement result.

[0044] Based on the nonlinear error index, using time reversal recursive reconstruction compensation algorithm, by introducing piecewise high-order tensor mapping, error reconstruction and correction, dynamic error compensation processing is carried out on the digital signal, and further, the measurement result is obtained by calculating and analyzing the compensated digital signal, the specific implementation process is as follows:

[0045] In order to judge whether the current error has structural or random nature, the time reversal mapping structure is constructed, that is, the mirror transformation of the digital signal in the local observation window is carried out based on error correction feedback, so as to generate a group of inversion samples:

[0046]

[0047] Among them, Indicates the inversion window transformation; Indicates the local observation window after inversion transformation; And Indicates the digital signal of the first And the digital signal of the first After the slope period processing of the inversion of the first Class; , .

[0048] Further, based on the time reversal error compensation algorithm, the inversion structure error mapping function Is defined to describe the degree of asymmetry between the inverted digital signals:

[0049]

[0050] Among them, Indicates the inversion error intensity at time ; Is the weight coefficient of the first Class digital signal, which is used to control the weighted influence of error intensity, which is determined according to expert experience method, and the reference value range is ; Is the smoothing factor of the first Class digital signal, which is used to smooth the nonlinear characteristics of the digital signal error, which is determined according to expert experience method, and the reference value range is ; Indicates the digital signal of the first Class after the slope period processing of the inversion of the first Class at time ; Indicates the digital signal of the first Class after the slope period processing of the first Class at time . ​

[0051] After obtaining the inversion error intensity, a third-order tensor structure is constructed to extract the coupling mode between multi-dimensional errors . The three layers of the tensor record the digital signal data in the current point, forward window, and backward window, respectively, where each component of the tensor is defined as:

[0052]

[0053] wherein, represents the first component of the tensor; represents the second component of the tensor; represents the third component of the tensor; represents the digital signal of the first type processed by the first slope period at time ; represents the digital signal of the second type processed by the second slope period at time ; represents the digital signal of the third type processed by the third slope period at time ; represents the digital signal of the fourth type processed by the fourth slope period at time . The coupling error offset is then calculated according to the above tensor, which is mathematically expressed as:

[0054]

[0055]

[0056] wherein, is the coupling error offset at time ; is the average value of the third-order tensor structure in the first component, ; represents the first component of the tensor. The above process captures the degree of error symmetry breaking through the cubic deviation , and identifies the non-periodic mutation mode through the square root and sine function, thereby realizing multi-dimensional high-order error analysis. Through the tensor within the local observation window, the total offset of the error deformation trend, i.e. , is extracted as the main driving force for subsequent signal compensation.

[0057] The calculated coupling error offset is combined with the nonlinear error index and the inversion error intensity .​​​​​, construct a correction amount feedback, and compensate the digital signal based on the correction amount feedback to obtain a compensated digital signal:

[0058]

[0059] wherein, represents the time point , the compensated digital signal of the th slope period processing; is a compensation adjustment coefficient, representing a correction compensation response degree to the error, and is determined according to an expert experience method, and a reference value range is .

[0060] To prevent the error compensation process from introducing reverse oscillation or overcompensation phenomenon, after each feedback, it is determined according to an expert experience method whether the compensated digital signal of the current output is located in a stable reference domain preset according to an expert experience method. If it is located in the stable reference domain, the compensation is completed; otherwise, it is considered as compensation overshoot or pseudo-correction introduction, and needs to be rolled back and re-evaluated , until the compensated digital signal is located in the stable reference domain.

[0061] Finally, based on the compensated digital signal, the existing electric energy calculation formula is used for calculation and analysis to obtain a metering result.

[0062] In summary, the electric energy metering method based on the multi-slope integration ADC and dynamic error compensation is completed.

[0063] The order of the embodiments of the application is only for description, and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multi-task processing and parallel processing are also possible or can be advantageous.

[0064] Each embodiment in the specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other. Each embodiment mainly describes the differences from other embodiments.

[0065] The above embodiments are only used to illustrate the technical solutions of the present application, but not limit the same. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to some technical features. The modification or replacement does not make the essence of the corresponding technical solution deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.​

Claims

1. An electric energy metering method based on multi-slope integral ADC and dynamic error compensation is characterized in that: The following steps are involved: S1. Obtain the original analog signal and perform analog-to-digital conversion on it to obtain a digital signal. At the same time, during the analog-to-digital conversion process, establish a local observation window and introduce a nonlinear differential index function. By calculating the offset degree of the digital signal at the relatively symmetrical position in the local observation window under the nonlinear measurement, the nonlinear error index is obtained. The calculation formula is: ； in, It is After the slope cycle processing A digital signal at time Nonlinear error index of ; is the number of time points; Indicates at time , No. After the slope cycle processing Class of digital signal; Indicates at time , No. After the slope cycle processing Class of digital signal; S2. Based on the nonlinear error index, the time reversal recursive reconstruction compensation algorithm is used to construct a time reversal mapping structure, and the digital signal in the local observation window is mirrored to generate an inverted digital signal; based on the inverted digital signal, the time reversal error compensation algorithm is used to define the inversion structure error mapping function to describe the degree of asymmetry between the inverted digital signals and generate the inversion error intensity; based on the inversion error intensity, a third-order tensor structure is constructed to calculate the coupling error offset; based on the coupling error offset, the nonlinear error index and the inversion error intensity, a correction feedback is constructed to generate the compensated digital signal; the compensated digital signal is calculated and analyzed, and after each feedback, it is determined whether the currently output compensated digital signal is within the preset stable reference domain. If it is within the stable reference domain, the compensation is completed, otherwise it is necessary to back off and re-evaluate the coupling error offset until the compensated digital signal is within the stable reference domain to obtain the measurement result.

2. The electric energy metering method based on multi-slope integral ADC and dynamic error compensation according to claim 1, characterized in that: Said S1 specifically includes: The original analog signal is converted into a digital signal by using a multi-slope integral analog-to-digital conversion method.

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