Method and system for measuring equivalent capacitance of ozone generator based on data fitting

Abstract

The invention provides a DBD (Dielectric Barrier Discharge) type ozone generator parameter measurement method and a DBD (Dielectric Barrier Discharge) type ozone generator parameter measurement system based on data fitting. The method specifically comprises the following steps of load voltage and current acquisition, capacitance voltage virtualization measurement, curve fitting, slope clustering, DBD type ozone generator equivalent capacitance output and the like. According to the method, a measuring circuit in a traditional scheme is not needed, and the equivalent capacitance of the DBD type ozone generator can be automatically calculated through a program. The method not only has the advantages of high applicability and accurate measurement result, but also overcomes the defects of long time consumption and low precision of the existing method for solving the equivalent capacitance through the Lissajous figure.

Description

Technical Field

[0001] The present invention belongs to the field of electrical parameter measurement, and specifically relates to a DBD type ozone generator equivalent capacitance measurement method and system. The invention uses a computer program to virtually generate the Lissajous figure of the generator to obtain the equivalent capacitance, aiming to reduce the cumbersomeness of the equivalent capacitance measurement process of the conventional dielectric barrier discharge ozone generator and the defect of having to build a test system. Background Art

[0002] The equivalent capacitance of DBD ozone generator generally includes dielectric layer equivalent capacitance and air gap equivalent capacitance. In practical applications, the measurement of these two parameters generally adopts Lissajous figure method, that is, the Lissajous figure is formed by the terminal voltage of the ozone generator and the charge flowing through the generator, and is calculated using the relevant calculation formula.

[0003] In order to obtain the charge flowing through the generator, a test capacitor must be constructed. The usual practice is to connect a measuring capacitor in series in the main circuit. The test process is cumbersome and has certain risks. In addition to the above defects, the accuracy of the generator equivalent capacitance is very dependent on the quality of the Lissajous figure, and the quality of the Lissajous figure is very dependent on the test system structure and the performance of the components in the test system.

[0004] To solve this problem, this patent proposes a method for obtaining the equivalent capacitance of a dielectric barrier discharge ozone generator. Compared with the traditional method, this method does not require the construction of a dedicated test system, nor does it rely on the quality of the Lissajous figure. This method can not only greatly reduce the workload of the test process, but also directly avoid the measurement error caused by the low quality of the Lissajous figure data. Summary of the invention

[0005] The present invention proposes a DBD (Dielectric Barrier Discharge) type ozone generator parameter measurement method based on data fitting. The method collects dielectric barrier load voltage and load current, and reconstructs the dielectric barrier load voltage and virtual measurement capacitor voltage through a data fitting method. Based on the reconstructed data, a differential algorithm is used to calculate the slope of the straight line formed by adjacent data points, so as to filter and cluster these slopes. Based on the clustering results, the load equivalent capacitance value is calculated.

[0006] The DBD (Dielectric Barrier Discharge) type ozone generator parameter measurement method based on data fitting proposed in the present invention consists of the following main steps:

[0007] Collecting the load voltage and load current of the DBD type ozone generator when it is working, and storing the collected load voltage and load current data;

[0008] Performing harmonic analysis on the stored load voltage to obtain a fundamental component and a main harmonic component of the load voltage;

[0009] Performing an integration operation on the stored load current to obtain a virtual measurement capacitor voltage, and performing a harmonic analysis on the virtual measurement capacitor voltage to obtain a fundamental component and a main harmonic component of the virtual measurement capacitor voltage;

[0010] Performing curve fitting on the load voltage and the virtual measurement capacitor voltage according to the fundamental wave components and main harmonic components of the load voltage and the virtual measurement capacitor voltage, and reconstructing the load voltage and the virtual measurement capacitor voltage according to the fitted expressions;

[0011] Constructing coordinate points with the values ​​of the reconstructed load voltage and the virtual measurement capacitor voltage at corresponding sampling moments, calculating the slopes of adjacent coordinate points, clustering the slopes into clusters with a number of clusters being 2, and obtaining the centroid values ​​of the clusters;

[0012] The equivalent capacitance of the DBD type ozone generator is calculated according to the centroid value of the cluster.

[0013] Furthermore, the step of "collecting the load voltage and load current of the DBD type ozone generator when it is working, and storing the collected load voltage and load current data" includes the following requirements:

[0014] The load voltage can be obtained by using a voltage acquisition scheme such as a resistor voltage divider, a voltage transformer and a high-voltage probe, and the load current can be obtained by using a current acquisition scheme such as a current transformer and a current probe;

[0015] The frequency of data collection should not be less than 100 times the operating frequency of the DBD type load generator;

[0016] The length of time for storing data should not be less than two complete working cycles of the DBD type load generator.

[0017] Further, the step of “performing an integration operation on the stored load current to obtain a virtual measurement capacitor voltage, and performing harmonic analysis on the virtual measurement capacitor voltage to obtain a main harmonic component of the virtual measurement capacitor voltage” includes the following requirements:

[0018] The integral operation expression is: Where V cm is the virtual measurement capacitor voltage, i DBD is the load current, T s is the time interval of data collection, that is, the inverse of the frequency data collection, k is the kth value in the sampling sequence, and ∑ is the summation symbol;

[0019] Further, the step of "performing curve fitting on the load voltage and the virtual measurement capacitor voltage according to the harmonic components of the load voltage and the virtual measurement capacitor voltage, and reconstructing the load voltage and the virtual measurement capacitor voltage according to the fitted expression" includes the following requirements:

[0020] The fitting expression is composed of sine waves and cosine waves of different frequencies;

[0021] The curve fitting is achieved by adjusting the amplitude and phase of the sine wave and the cosine wave;

[0022] Furthermore, the step of "constructing coordinate points using the values ​​of the reconstructed load voltage and the virtual measurement capacitor voltage at the corresponding sampling time, calculating the slopes of adjacent coordinate points, clustering the slopes into 2 clusters, and obtaining the centroid values ​​of the clusters" includes the following requirements:

[0023] The expression of the coordinate point is [V r_DBD (k),V r_cm (k)], where V r_DBD is the reconstructed load voltage, V r_cm is the reconstructed virtual measurement capacitor voltage, k is the kth value of the reconstructed load voltage and the reconstructed virtual measurement capacitor voltage;

[0024] The slope calculation expression is:

[0025] l(k)=(V r_cm (k+1)-V r_cm (k)) / (V r_DBD (k+1)-V r_DBD (k)), where l is the

[0026] The slope of the adjacent coordinate points, k+1 is the k+1th value of the reconstructed load voltage and the reconstructed virtual measurement capacitor voltage;

[0027] Furthermore, the step of "calculating the equivalent capacitance of the DBD type ozone generator according to the centroid value of the cluster" includes the following requirements:

[0028] The equivalent capacitance includes the barrier dielectric capacitance and air gap capacitance of the DBD type ozone generator, which is calculated as: C d =K1, C p =K2, C g =C d C p / (C d -C p ), where C dis the blocking dielectric capacitance, C p is the series value of the blocking dielectric capacitance and the air gap capacitance, C g is the air gap capacitance, K1 and K2 are the two centroid values ​​of the cluster;

[0029] In addition, the present invention also provides a DBD type ozone generator equivalent capacitance measurement system based on data fitting, including the following modules:

[0030] Data acquisition module: used for collecting the load voltage and load current;

[0031] A virtual measurement capacitor voltage construction module: used to construct a virtual measurement capacitor voltage through the load current;

[0032] Harmonic analysis module: used for analyzing the fundamental component and main harmonic component of the load voltage and the virtual measurement capacitor voltage;

[0033] Voltage reconstruction module: used for reconstructing the load voltage and the virtual measurement capacitor voltage;

[0034] Slope clustering module: used to calculate the slopes of adjacent coordinate points, obtain the centroid of the slope clustering cluster, and implement equivalent capacitance measurement using the aforementioned method.

[0035] Beneficial effects:

[0036] The present invention provides a DBD (Dielectric Barrier Discharge) type ozone generator parameter measurement method and system based on data fitting. Specifically, the following steps are included: load voltage, current acquisition, measurement capacitor voltage virtualization, curve fitting, slope clustering and DBD type ozone generator equivalent capacitance output. This method does not require the measurement circuit of the traditional solution, and can automatically calculate the equivalent capacitance of the DBD type ozone generator through a program. This method not only has the advantages of strong applicability and accurate measurement results, but also solves the defects of the existing method of obtaining equivalent capacitance through Lissajous figures, which is time-consuming and low in precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a flow chart of the measurement method;

[0038] Figure 2 It is a commonly used DBD type ozone generator Lissajous figure measurement system;

[0039] Figure 3 This is the Lissajous figure of DBD type ozone generator;

[0040] Figure 4 This is the load voltage fitting effect diagram;

[0041] Figure 5Comparison of Lissajous figures obtained by two methods. DETAILED DESCRIPTION

[0042] In the following description, many technical details are provided to help readers better understand the present application. However, those skilled in the art can understand that even without these technical details and various changes and modifications based on the following implementations, the technical solutions claimed in the claims of the present application can be implemented. Figure 1 As shown, the following will be discussed in detail.

[0043] The DBD (Dielectric Barrier Discharge) type ozone generator parameter measurement method based on data fitting proposed in the present invention consists of the following main steps:

[0044] Collecting the load voltage and load current of the DBD type ozone generator when it is working, and storing the collected load voltage and load current data;

[0045] Performing harmonic analysis on the stored load voltage to obtain a fundamental component and a main harmonic component of the load voltage;

[0046] Performing an integration operation on the stored load current to obtain a virtual measurement capacitor voltage, and performing a harmonic analysis on the virtual measurement capacitor voltage to obtain a fundamental component and a main harmonic component of the virtual measurement capacitor voltage;

[0047] Performing curve fitting on the load voltage and the virtual measurement capacitor voltage according to the fundamental wave components and main harmonic components of the load voltage and the virtual measurement capacitor voltage, and reconstructing the load voltage and the virtual measurement capacitor voltage according to the fitted expressions;

[0048] Constructing coordinate points with the values ​​of the reconstructed load voltage and the virtual measurement capacitor voltage at corresponding sampling moments, calculating the slopes of adjacent coordinate points, clustering the slopes into clusters with a number of clusters being 2, and obtaining the centroid values ​​of the clusters;

[0049] The equivalent capacitance of the DBD type ozone generator is calculated according to the centroid value of the cluster.

[0050] Furthermore, the step of "collecting the load voltage and load current of the DBD type ozone generator when it is working, and storing the collected load voltage and load current data" includes the following requirements:

[0051] The load voltage can be obtained by using a voltage acquisition scheme such as a resistor voltage divider, a voltage transformer and a high-voltage probe, and the load current can be obtained by using a current acquisition scheme such as a current transformer and a current probe;

[0052] The frequency of data collection should not be less than 100 times the operating frequency of the DBD type load generator;

[0053] The length of time for storing data should not be less than two complete working cycles of the DBD type load generator.

[0054] Further, the step of “performing an integration operation on the stored load current to obtain a virtual measurement capacitor voltage, and performing harmonic analysis on the virtual measurement capacitor voltage to obtain a main harmonic component of the virtual measurement capacitor voltage” includes the following requirements:

[0055] The integral operation expression is: Where V cm is the virtual measurement capacitor voltage, i DBD is the load current, T s is the time interval of data collection, that is, the inverse of the frequency data collection, k is the kth value in the sampling sequence, and ∑ is the summation symbol;

[0056] Further, the step of "performing curve fitting on the load voltage and the virtual measurement capacitor voltage according to the harmonic components of the load voltage and the virtual measurement capacitor voltage, and reconstructing the load voltage and the virtual measurement capacitor voltage according to the fitted expression" includes the following requirements:

[0057] The fitting expression is composed of sine waves and cosine waves of different frequencies;

[0058] The curve fitting is achieved by adjusting the amplitude and phase of the sine wave and the cosine wave;

[0059] Furthermore, the step of "constructing coordinate points using the values ​​of the reconstructed load voltage and the virtual measurement capacitor voltage at the corresponding sampling time, calculating the slopes of adjacent coordinate points, clustering the slopes into 2 clusters, and obtaining the centroid values ​​of the clusters" includes the following requirements:

[0060] The expression of the coordinate point is [V r_DBD (k),V r_cm (k)], where V r_DBD is the reconstructed load voltage, V r_cm is the reconstructed virtual measurement capacitor voltage, k is the kth value of the reconstructed load voltage and the reconstructed virtual measurement capacitor voltage;

[0061] The slope calculation expression is:

[0062] l(k)=(V r_cm (k+1)-V r_cm (k)) / (V r_DBD (k+1)-V r_DBD (k)), where l is the

[0063] The slope of the adjacent coordinate points, k+1 is the k+1th value of the reconstructed load voltage and the reconstructed virtual measurement capacitor voltage;

[0064] Furthermore, the step of "calculating the equivalent capacitance of the DBD type ozone generator according to the centroid value of the cluster" includes the following requirements:

[0065] The equivalent capacitance includes the barrier dielectric capacitance and air gap capacitance of the DBD type ozone generator, which is calculated as: C d =K1, C p =K2, C g =C d C p / (C d -C p ), where C d is the blocking dielectric capacitance, C p is the series value of the blocking dielectric capacitance and the air gap capacitance, C g is the air gap capacitance, K1 and K2 are the two centroid values ​​of the cluster;

[0066] In addition, the present invention also provides a DBD type ozone generator equivalent capacitance measurement system based on data fitting, including the following modules:

[0067] Data acquisition module: used for collecting the load voltage and load current;

[0068] A virtual measurement capacitor voltage construction module: used to construct a virtual measurement capacitor voltage through the load current;

[0069] Harmonic analysis module: used for analyzing the fundamental component and main harmonic component of the load voltage and the virtual measurement capacitor voltage;

[0070] Voltage reconstruction module: used for reconstructing the load voltage and the virtual measurement capacitor voltage;

[0071] Slope clustering module: used to calculate the slopes of adjacent coordinate points and obtain the centroid of slope clustering clusters;

[0072] Specifically, step 1: select appropriate voltage and current measuring components according to the working voltage and working current of the DBD type ozone generator, such as selecting a voltage probe with a withstand voltage of 10kV and a current probe with a rated current of 10A;

[0073] Step 2: Set a suitable sampling frequency. Considering that the operating frequency of the DBD ozone generator is generally several thousand hertz, you can choose to directly connect the voltage probe and current probe to the oscilloscope and use the high sampling frequency of the oscilloscope to obtain suitable data. For example, choose an oscilloscope with a sampling rate of 100 MHz as a data acquisition and data storage component.

[0074] Step 3: Import the stored data in the oscilloscope into mathematical analysis tools (such as MATLAB, etc.) to analyze the harmonic composition of the working voltage and working current of the DBD type ozone generator;

[0075] Step 4: Perform discrete integration operation on the working current of the DBD type ozone generator to obtain the virtual measurement capacitor voltage;

[0076] Step 5: Based on the harmonic composition characteristics obtained in step 3, use relevant mathematical analysis tools to adjust the amplitude and phase of each sine wave and cosine wave to make the sampling result as close as possible to the fitting result of the load voltage and the virtual measurement capacitor voltage. Figure 4 The load voltage fitting results under a set of measurement data are given;

[0077] Step 6: Reconstruct the load voltage and the virtual measurement capacitor voltage according to the fitting function and the original sampling time interval, and form a data set;

[0078] Step 7: Use the difference method to calculate the slope of two adjacent data points and form a slope storage array. The calculation formula is:

[0079] k=(y[n+1]-y[n]) / (x[n+1]-x[n])

[0080] Here, (x[n], y[n]) and (x[n+1], y[n+1]) are the horizontal and vertical coordinates of two adjacent data points. Step 8: Use the K-means clustering method to cluster the slope storage array obtained in step 7 to obtain the two most accurate ranges of the slope, and on this basis, obtain the centroid value of the clustering result;

[0081] Step 9: Using Calculation Expression: C d =K1, C p =K2, C g =C d C p / (C d -C p) to calculate the equivalent capacitance value of the DBD ozone generator. Among them, C d is the blocking dielectric capacitance, C p is the series value of the blocking dielectric capacitance and the air gap capacitance, C g is the air gap capacitance, K1 and K2 are the two centroid values ​​of the cluster.

Claims

1. A method for measuring equivalent capacitance of ozone generator based on data fitting, It is characterized by the following steps: Collecting the load voltage and load current of the DBD type ozone generator when it is working, and storing the collected load voltage and load current data; Performing harmonic analysis on the stored load voltage to obtain a fundamental component and a main harmonic component of the load voltage; Performing an integration operation on the stored load current to obtain a virtual measurement capacitor voltage, and performing a harmonic analysis on the virtual measurement capacitor voltage to obtain a fundamental component and a main harmonic component of the virtual measurement capacitor voltage; Performing curve fitting on the load voltage and the virtual measurement capacitor voltage according to the fundamental wave components and main harmonic components of the load voltage and the virtual measurement capacitor voltage, and reconstructing the load voltage and the virtual measurement capacitor voltage according to the fitted expressions; Constructing coordinate points with the values ​​of the reconstructed load voltage and the virtual measurement capacitor voltage at corresponding sampling moments, calculating the slopes of adjacent coordinate points, clustering the slopes into clusters with a number of clusters being 2, and obtaining the centroid values ​​of the clusters; The equivalent capacitance of the DBD type ozone generator is calculated according to the centroid value of the cluster.

2. The method for measuring equivalent capacitance of an ozone generator based on data fitting according to claim 1, characterized in that: The step of "collecting the load voltage and load current of the DBD type ozone generator when it is working, and storing the collected load voltage and load current data" includes the following requirements: The load voltage can be obtained by using a voltage acquisition scheme such as a resistor voltage divider, a voltage transformer and a high-voltage probe, and the load current can be obtained by using a current acquisition scheme such as a current transformer and a current probe; The frequency of data collection should not be less than 100 times the operating frequency of the DBD type load generator; The length of time for storing data should not be less than two complete working cycles of the DBD type load generator.

3. The method for measuring equivalent capacitance of an ozone generator based on data fitting according to claim 1, characterized in that: The step of "performing an integration operation on the stored load current to obtain a virtual measurement capacitor voltage, and performing harmonic analysis on the virtual measurement capacitor voltage to obtain a main harmonic component of the virtual measurement capacitor voltage" includes the following requirements: The integral operation expression is: Where V cm is the virtual measurement capacitor voltage, i DBD is the load current, T s is the time interval for data collection, that is, the inverse of the frequency data collection, k is the kth value in the sampling sequence, and ∑ is the summation symbol.

4. The method for measuring equivalent capacitance of an ozone generator based on data fitting according to claim 1, characterized in that: The step of "performing curve fitting on the load voltage and the virtual measurement capacitor voltage according to the harmonic components of the load voltage and the virtual measurement capacitor voltage, and reconstructing the load voltage and the virtual measurement capacitor voltage according to the fitted expression" includes the following requirements: The fitting expression is composed of sine waves and cosine waves of different frequencies; The curve fitting is achieved by adjusting the amplitude and phase of the sine wave and the cosine wave.

5. The method for measuring equivalent capacitance of an ozone generator based on data fitting according to claim 1, characterized in that: The step of "constructing coordinate points with the values ​​of the reconstructed load voltage and the virtual measurement capacitor voltage at the corresponding sampling time, calculating the slopes of adjacent coordinate points, clustering the slopes into 2 clusters, and obtaining the centroid values ​​of the clusters" includes the following requirements: The expression of the coordinate point is [V r_DBD (k),V r_cm (k)], where V r_DBD is the reconstructed load voltage, V r_cm is the reconstructed virtual measurement capacitor voltage, k is the kth value of the reconstructed load voltage and the reconstructed virtual measurement capacitor voltage; The slope calculation expression is: l(k)=(V r_cm (k+1)-V r_cm (k)) / (V r_DBD (k+1)-V r_DBD (k)), where l is the slope of the adjacent coordinate points, and k+1 is the k+1th value of the reconstructed load voltage and the reconstructed virtual measurement capacitor voltage.

6. The method for measuring equivalent capacitance of an ozone generator based on data fitting according to claim 1, characterized in that: The step of "calculating the equivalent capacitance of the DBD type ozone generator according to the centroid value of the cluster" These include the following requirements: The equivalent capacitance includes the barrier dielectric capacitance and air gap capacitance of the DBD type ozone generator, which is calculated as: C d =K1, C p =K2, C g =C d C p / (C d -C p ), where C d is the blocking dielectric capacitance, C p is the series value of the blocking dielectric capacitance and the air gap capacitance, C g is the air gap capacitance, K1 and K2 are the two centroid values ​​of the cluster.

7. An ozone generator equivalent capacitance measurement system based on data fitting, characterized in that: Includes the following modules: Data acquisition module: used for collecting the load voltage and load current; A virtual measurement capacitor voltage construction module: used to construct a virtual measurement capacitor voltage through the load current; Harmonic analysis module: used for analyzing the fundamental component and main harmonic component of the load voltage and the virtual measurement capacitor voltage; Voltage reconstruction module: used for reconstructing the load voltage and the virtual measurement capacitor voltage; Slope clustering module: used to calculate the slopes of adjacent coordinate points and obtain the centroid of slope clustering clusters; The equivalent capacitance measurement is implemented by the method described in any one of claims 1 to 6.

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