Multi-point correction method, system and sampling method

Abstract

The present application relates to a kind of multi-point correction method, system and sampling method.Multi-point correction method is: based on the value range of the physical quantity to be sampled, select multiple correction points, and store the correction data corresponding to each correction point, correction data includes the device theoretical sampling physical quantity corresponding to sampling point and its corresponding actual physical quantity;When sampling device detects the correction instruction to any one correction point, then update the correction data corresponding to the storage correction point.The multi-point correction system includes the MCU and storage device connected by communication.Sampling method is: after the sampling device after starting sampling using the above multi-point correction method is corrected, read the correction data corresponding to each correction point stored and calculate to obtain sampling correction function, so as to the device theoretical sampling physical quantity of current sampling, using sampling correction function calculates to obtain the actual physical quantity corresponding to current sampling.The present application has the advantages of good flexibility, weak dependence.

Description

Technical Field

[0001] This invention belongs to the field of system data processing technology, specifically relating to a multi-point correction method, system, and sampling method for sampled data. Background Technology

[0002] High-precision data sampling is a prerequisite for achieving high-precision control. For example, with the increasing prevalence of photovoltaic (PV) power generation systems and the growing number of PV systems connected to the grid, power grid companies are placing increasingly stringent demands on the functionality and control precision of these systems. Achieving multifunctional, high-precision control not only enhances the stability of the power system but also provides customers with a superior product experience. However, from a software and hardware development perspective, achieving high-precision control requires the system to sample voltage, current, and other signals with high precision. Furthermore, due to inherent differences between hardware of the same specifications from different devices, the actual sampling may exhibit deviations, resulting in errors between the actual signal and the device's sampled signal, thus affecting the control precision of the PV power generation system.

[0003] Currently, a common solution to the problem of achieving high-precision sampling is to add a software calibration process. This method calibrates the actual physical quantity (obtained through external high-precision measuring equipment) and the theoretical sampling physical quantity (calculated through the relationship between the equipment hardware and sensors). It converts the theoretical sampling physical quantity into the actual physical quantity by designing a mathematical function, thus obtaining accurate sampling data. The mathematical function obtained through calibration is stored in a storage device (such as Flash). Each time the device is powered on, the stored mathematical function is read and used to calculate the theoretical and actual sampling physical quantities, as shown in the appendix. Figure 4 As shown.

[0004] Among them, the commonly used mathematical function is a linear function: Y = kX + b, where Y is the actual physical quantity, X is the theoretical sampled physical quantity of the equipment, k is the proportion of the linear function, and b is the bias.

[0005] Common calibration methods include single-point calibration and multi-point calibration. Single-point calibration is typically performed under conditions where the equipment operates frequently, such as the rated operating point. However, it suffers from significant errors when operating far from the calibration point, as shown in Figure 1. Multi-point calibration, to meet the needs of various operating conditions, effectively solves the error problems of single-point calibration by adding calibration points, such as... Figure 2 As shown. However, as attached Figure 3As shown, traditional multi-point calibration methods require calibrating the information of all calibration points separately before updating and storing the mathematical function, resulting in poor flexibility. If the calibration data at any one point is faulty, all points need to be recalibrated, making it impossible to calibrate a single point individually. Furthermore, traditional multi-point calibration methods have strict requirements for the testing environment. If accuracy issues arise in the field, limitations in the field conditions may prevent the provision of operating conditions that satisfy all calibration points, thus making calibration impossible. Summary of the Invention

[0006] The purpose of this invention is to provide a multi-point calibration method that offers greater flexibility and reduces dependence on the calibration environment.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A multi-point calibration method is applied in a sampling device. The multi-point calibration method is as follows: based on the value range of the physical quantity to be sampled, multiple calibration points are selected, and calibration data corresponding to each calibration point is stored. The calibration data includes the theoretical physical quantity to be sampled by the device corresponding to the sampling point and its corresponding actual physical quantity. When the sampling device detects a calibration command for any one of the calibration points, the stored calibration data corresponding to the calibration point is updated.

[0009] When the sampling device is started for the first time, the correction data corresponding to each correction point is initialized to the corresponding theoretical value.

[0010] Before updating the stored correction data corresponding to the correction point, it is first determined whether the correction data corresponding to the correction point to be updated is reasonable. If it is reasonable, the data is updated; otherwise, the correction data corresponding to the correction point to be updated is initialized to the corresponding theoretical value.

[0011] The method for determining whether the correction data corresponding to the correction point to be updated is reasonable is as follows: if the correction data to be updated is within the allowable deviation range of the corresponding theoretical value, then the correction data corresponding to the correction point to be updated is reasonable.

[0012] The calibration points are calibrated under different operating conditions.

[0013] After updating the stored correction data corresponding to the correction point, the sampling correction function is calculated segment by segment based on the stored correction data corresponding to the correction point.

[0014] The correction points are selected at uniform intervals.

[0015] This invention also provides a multi-point correction system for implementing the above-described multi-point correction method, the scheme of which is:

[0016] A multi-point calibration system includes an MCU and a storage device connected in communication. The storage device stores calibration data corresponding to each calibration point. The MCU controls the storage device to update the stored calibration data corresponding to each calibration point according to the calibration instructions for that calibration point. The storage device is a FLASH memory.

[0017] This invention also provides a sampling method based on the above-mentioned multi-point correction method, which can obtain actual physical quantities more flexibly and accurately, thereby improving the calculation or control accuracy of subsequent systems. The scheme is as follows:

[0018] A sampling method is applied to a sampling device employing the above-mentioned multi-point correction method. The sampling method is as follows: after the sampling device starts sampling, it reads the correction data corresponding to each of the stored correction points and calculates the sampling correction function, thereby calculating the actual physical quantity corresponding to the current sampling based on the theoretical sampling physical quantity of the device.

[0019] Each segment of the sampling correction function is a linear function or a multi-function.

[0020] Due to the application of the above technical solutions, the present invention has the following advantages compared with the prior art: 1. The multi-point calibration method and device of the present invention solves the problems of poor flexibility and heavy dependence on the calibration environment of traditional multi-point calibration methods, and has the advantages of good flexibility and weak dependence; 2. The sampling method of the present invention is flexible and accurate, which is conducive to the application of sampling data. Attached Figure Description

[0021] Appendix Figure 1 This is a schematic diagram illustrating the error of existing single-point correction methods.

[0022] Appendix Figure 2 This is a schematic diagram illustrating the error of existing multi-point correction methods.

[0023] Appendix Figure 3 This is a flowchart of an existing multi-point correction method.

[0024] Appendix Figure 4 This is a block diagram of a device that applies an existing multi-point correction method.

[0025] Appendix Figure 5 This is a flowchart of the multi-point correction method of the present invention.

[0026] Appendix Figure 6 This is a flowchart of the sampling method of the present invention.

[0027] Appendix Figure 7 This is a block diagram of the multi-point correction system of the present invention.

[0028] Appendix Figure 8 This is a schematic diagram of the correction point in this invention. Detailed Implementation

[0029] The present invention will be further described below with reference to the embodiments shown in the accompanying drawings.

[0030] Example 1: A novel multi-point calibration method applied to sampling equipment. This method eliminates the need to store the sampling calibration function (mathematical function) in a storage device. Instead, it stores the theoretical and actual physical quantities of the sampling points during the multi-point calibration process. During sampling, the mathematical function is calculated by reading the theoretical and actual physical quantities of the device each time it is powered on. The specific scheme is as follows:

[0031] As attached Figure 5 As shown, a multi-point calibration method is as follows: Based on the value range of the physical quantity to be sampled, multiple calibration points are selected. These calibration points can be selected at uniform intervals, and calibration data corresponding to each calibration point is stored. The calibration data includes the theoretically sampled physical quantity of the device corresponding to the sampling point and its corresponding actual physical quantity. When the sampling device detects a calibration command for any calibration point, the stored calibration data corresponding to that calibration point is updated. Calibration is performed on different calibration points under different operating conditions. After updating the stored calibration data corresponding to the calibration points, a sampling calibration function is calculated piecewise based on the stored calibration data corresponding to the calibration points.

[0032] In this multi-point calibration method, when the sampling device is started for the first time, the calibration data corresponding to each calibration point is initialized to the corresponding theoretical value. Before updating the stored calibration data corresponding to the calibration points, it is first determined whether the calibration data corresponding to the calibration point to be updated is reasonable. If it is reasonable, the data is updated; otherwise, the calibration data corresponding to the calibration point to be updated is initialized to the corresponding theoretical value. The method for determining whether the calibration data corresponding to the calibration point to be updated is reasonable is as follows: if the calibration data to be updated is within the allowable deviation range of the corresponding theoretical value, then the calibration data corresponding to the calibration point to be updated is reasonable.

[0033] The following example uses the correction of the DC side voltage of a photovoltaic panel in a photovoltaic power generation system (this example only uses the DC side voltage parameter of the photovoltaic panel as an example; other parameters of the photovoltaic power generation system can also be sampled, and it is not limited to the parameters on the photovoltaic panel side, nor is it limited to the specific parameter type).

[0034] For the DC side voltage of the photovoltaic panel, the theoretical sampling voltage (the theoretical sampling physical quantity of the equipment) obtained through sampling calculation is V. PV’ The actual sampled voltage (actual physical quantity) obtained through external high-precision measuring equipment is V. PV Then V PV =f(V PV’ ).

[0035] The maximum sampling voltage for the DC side voltage of the photovoltaic panel is defined as 600V, meaning the range of the DC side voltage of the photovoltaic panel is 0 to 600V. Based on experience, the rated operating points of 180V (30%), 360V (60%), and 540V (90%) are selected as calibration points. (The calibration point is only a reference. In reality, due to the calibration auxiliary power supply equipment or errors, the measured value will eventually be near the calibration point, but the deviation will not be too large. If the deviation is too large, it will affect the effect of multi-point calibration. Taking 180V as an example, a voltage of 180V ± 30V can be considered within a reasonable range.)

[0036] As attached Figure 8 As shown, the corresponding correction data A(m) for each correction point is stored in the sampling device. a ,n a ), B(m b ,n b ) and C(m c ,n c ), where m a m b m c The theoretical sampling voltages (theoretical sampling physical quantities of the equipment) at points A, B, and C are respectively, n a n b n c These are the actual sampled voltages (actual physical quantities) at points A, B, and C, respectively. When the device is first started, no relevant data is stored, so the calibration data for each calibration point is initialized to the corresponding theoretical value A(m). a理论 ,n a理论 ), B(m b理论 ,n b理论 ) and C(m c理论 ,n c理论 ), where m a理论 =n a理论 m b理论 =n b理论 m c理论 =n c理论 .

[0037] Based on the corresponding correction data A(m) of each correction point a ,n a ), B(m b ,n b ) and C(m c ,n cThis allows for the calculation of sampling correction functions. The sampling correction function is a piecewise function with each correction point as a segment, and each segment is either a linear or multi-degree function. In this example, the mathematical functions are designed as follows: 0A: Y = k0X, AB: Y = k1X + b1, BC: Y = k2X + b2, and from C onwards: Y = k3X (the design of the mathematical functions is not limited to linear functions; only linear functions are used as examples here).

[0038] The complete mathematical function can be obtained by calculating using the following formula:

[0039] k0 = m a / n a ;

[0040] k1 = [n b -n a ] / [m b -m a ];

[0041] b1 = n b -k1m b ;

[0042] k2=[n c -n b ] / [m c -m b ];

[0043] b2 = n c -k1m c ;

[0044] k3=m c / n c .

[0045] Then the correction function V is obtained at this time. PV =f(V PV’ The relationship is as follows:

[0046] V PV =k0V PV’ (0≤V PV’ <m a );

[0047] V PV =k1V PV’ +b1(m a ≤V PV’ <m b );

[0048] V PV =k2V PV’ +b2(m b ≤V PV’ <m c );

[0049] V PV =k3V PV’ (m c ≤V PV’ )

[0050] Calibration is performed on different calibration points under different operating conditions. Specifically, calibration point A is calibrated when the equipment is operating under condition A, calibration point B is calibrated when the equipment is operating under condition B, and calibration point C is calibrated when the equipment is operating under condition C. When the sampling equipment detects a calibration command for any calibration point, such as point A, the data is updated, and A(m) in the calibration data is updated. a ,n a ), B(m b ,n b ) and C(m c ,n c ) was modified to A(m) a * ,n a * ), B(m b ,n b ) and C(m c ,n c Before updating, it is necessary to determine whether the data to be updated is reasonable. If the deviation value of the parameter at point A is large, exceeding the range of 180V±30V, then point A should be initialized to A(m). a理论 ,n a理论 After confirming the data, store the correction data for points A, B, and C, and update the mathematical function:

[0051] k0 = m a * / n a * ;

[0052] k1 = [n b -n a * ] / [m b -m a * ];

[0053] b1 = n b -k1m b ;

[0054] k2=[n c -n b ] / [m c -m b ];

[0055] b2 = n c -k1m c ;

[0056] k3=mc / n c .

[0057] Then we obtain the new correction function V. PV =f(V PV’ The relationship is as follows:

[0058] V PV =k0V PV’ (0≤V PV’ <m a * );

[0059] V PV =k1V PV’ +b1(m a * ≤V PV’ <m b );

[0060] V PV =k2V PV’ +b2(m b ≤V PV’ <m c );

[0061] V PV =k3V PV’ (m c ≤V PV’ ).

[0062] The sampling method implemented based on the above multi-point correction method is attached. Figure 6 As shown: After the sampling device starts sampling and initializes, it reads the correction data corresponding to each stored correction point and calculates the sampling correction function. After the system is running normally, it uses the sampling correction function to calculate the actual physical quantity corresponding to the current sampling based on the theoretical sampling physical quantity of the device.

[0063] Building on the previous example, the final step is to substitute the theoretically sampled physical quantities obtained from the sampling into the latest correction function V. PV =f(V PV’ By calculating these physical quantities, more accurate actual physical quantities can be obtained. Photovoltaic systems then use these actual physical quantities for power calculations or actual control, which not only enhances the stability of the power system but also provides customers with a better product experience.

[0064] The above method solves the problem that traditional multi-point calibration methods are inflexible and cannot calibrate a single point. By retaining the data of the previous calibration points, the calibration work can be completed by modifying only the required calibration points. It also solves the problem that multi-point calibration cannot be performed when only one environmental condition is provided. In other words, it solves the problem that traditional multi-point calibration methods are heavily dependent on the calibration environment. Multi-point calibration work can be completed using only the existing conditions.

[0065] As attached Figure 7 As shown, the multi-point calibration system implementing the above multi-point calibration method includes an MCU and a storage device connected by communication. The storage device stores calibration data corresponding to each calibration point, and the MCU controls the storage device to update the stored calibration data corresponding to the calibration point according to the calibration instructions for that calibration point. The storage device can be FLASH memory. The above sampling method can also be implemented through this system by adding relevant functions to the MCU.

[0066] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A multi-point calibration method, applied in a sampling device, characterized in that: The multi-point calibration method is as follows: based on the value range of the physical quantity to be sampled, multiple calibration points are selected, and calibration data corresponding to each calibration point is stored. The calibration data includes the theoretical physical quantity to be sampled by the device corresponding to the sampling point and its corresponding actual physical quantity. When the sampling device detects a calibration command for any one of the calibration points, the calibration data corresponding to the stored calibration point is updated. Before updating the stored calibration data corresponding to the calibration point, it is first determined whether the calibration data corresponding to the calibration point to be updated is reasonable. If it is reasonable, the data is updated; otherwise, the calibration data corresponding to the calibration point to be updated is initialized to the corresponding theoretical value.

2. The multi-point correction method according to claim 1, characterized in that: When the sampling device is started for the first time, the correction data corresponding to each correction point is initialized to the corresponding theoretical value.

3. The multi-point correction method according to claim 1, characterized in that: The method for determining whether the correction data corresponding to the correction point to be updated is reasonable is as follows: if the correction data to be updated is within the allowable deviation range of the corresponding theoretical value, then the correction data corresponding to the correction point to be updated is reasonable.

4. The multi-point correction method according to claim 1, characterized in that: The calibration points are calibrated under different operating conditions.

5. The multi-point correction method according to claim 1, characterized in that: After updating the stored correction data corresponding to the correction point, the sampling correction function is calculated segment by segment based on the stored correction data corresponding to the correction point.

6. The multi-point correction method according to claim 1, characterized in that: The correction points are selected at uniform intervals.

7. A multi-point calibration system for implementing the multi-point calibration method as described in any one of claims 1 to 6, characterized in that: The multi-point calibration system includes an MCU and a storage device connected in communication. The storage device is used to store calibration data corresponding to each calibration point. The MCU is used to control the storage device to update the calibration data corresponding to the calibration point according to the calibration instructions of the calibration point.

8. The multi-point calibration system according to claim 7, characterized in that: The storage device is FLASH.

9. A sampling method, applied in a sampling device employing the multi-point correction method as described in any one of claims 1 to 6, characterized in that: The sampling method is as follows: after the sampling device starts sampling, it reads the correction data corresponding to each of the stored correction points and calculates the sampling correction function, thereby calculating the actual physical quantity corresponding to the current sampling based on the theoretical sampling physical quantity of the device.

10. The sampling method according to claim 9, characterized in that: Each segment of the sampling correction function is a linear function or a multi-function.

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