Insulation resistance tester

Abstract

The invention discloses an insulation resistance tester, and relates to the technical field of resistance measurement, a test system in the insulation resistance tester forms a core architecture of the insulation resistance test system through mutual cooperation of three algorithm units, and comprehensively considers output voltage V, leakage current I and pressure variation. A pressure sensitivity coefficient and a positive and negative coefficient are introduced for automatic adjustment, a pressure compensation resistance value Rsc is obtained through calculation, the insulation resistance characteristic of a measured object under specific pressure can be reflected more accurately, and compared with a traditional megohmmeter, the insulation resistance tester can complete measurement of the absorption ratio and the polarization index of the measured object, and the measurement accuracy is improved. And when the resistance of the object is measured, the harmonic frequency deviation and the temperature change can be compensated, so that the interference of the harmonic frequency deviation and the temperature change on the resistance test result is reduced, the accuracy of the resistance test is improved, and the insulation resistance tester disclosed by the invention can adapt to wider test scenes.

Description

Technical Field

[0001] The present invention relates to the technical field of resistance measurement, and more specifically to an insulation resistance tester. Background Art

[0002] Insulation resistance refers to the resistance encountered by current when passing through an insulating medium in an electrical device or material.

[0003] Traditional megohmmeters (shake meters) are inexpensive, but their disadvantages are that a hand-cranked generator must be used and a speed of 120 revolutions per second must be maintained to sustain a normal output voltage. They have a small measurement range, large errors, and it is not very convenient to read according to the pointer index. Currently, in production and test sites, the measurement of insulation indicators for electrical equipment and electrical circuits is not limited to the measurement of insulation resistance, but other insulation indicators are also required, such as the absorption ratio and polarization index. The absorption ratio is the ratio of the insulation resistance value when the test sample is pressurized for 60 seconds to the insulation resistance when pressurized for 15 seconds, and the polarization index is the ratio of the insulation resistance value when the test sample is pressurized for 600 seconds to the insulation resistance when pressurized for 60 seconds.

[0004] Traditional megohmmeters can only measure insulation resistance and it is difficult to apply pressure during resistance measurement to complete the measurement of the absorption ratio and polarization index.

[0005] Moreover, in the field of insulation testing, the rate of periodic change of the alternating electric field applied across the insulation material to be tested, that is, the test frequency, will affect the resistance value by changing the internal polarization mechanism of the material. For example, in the insulation resistance test of composite materials, the space charge layer formed by the accumulation of charges in the alternating electric field is sensitive to frequency. At high frequencies, the measured resistance value will decrease by a certain amount. Traditional megohmmeters are also difficult to consider the influence of the rate of periodic change of the alternating electric field, that is, the test frequency on the resistance value during resistance testing, and the test range is small, and it can no longer meet the needs of current production development and is gradually being phased out.

[0006] Therefore, there is an urgent need for an insulation resistance tester to solve the above problems. Summary of the Invention

[0007] The purpose of the present invention is to provide an insulation resistance tester to solve the problems raised in the above background art.

[0008] To achieve the above purpose, the present invention provides the following technical solution: An insulation resistance tester, comprising: a high insulation resistance tester, an FFT spectrum analyzer, a pressure generating device, a pressure sensor, a temperature sensor, and a test system; The test system specifically includes: A data collection module for collecting resistance measurement data; A data preprocessing module for decoding and preprocessing the data information in the database to obtain the parameters for calculation in the calculation processing module; A calculation processing module for inputting the parameters obtained after decoding and preprocessing into the pressure compensation resistance value algorithm unit to calculate the pressure compensation resistance value Rsc, and uploading it to the database; Input the pressure compensation resistance value Rsc into the adjusted resistance value algorithm unit in the calculation processing module, and calculate the adjusted resistance value Rfa by combining the frequency influence term and the temperature deviation influence, and upload it to the database; Input the adjusted resistance value Rfa and the pressure compensation resistance value Rsc into the pressure sensitivity coefficient adjustment value algorithm unit in the calculation processing module to calculate the pressure sensitivity coefficient α in the (t + 1)-th calculation t+1 and upload it to the database.

[0009] Optionally, the collection of resistance measurement data specifically includes: Obtain the output voltage V and leakage current I during resistance measurement through an insulation resistance tester; Obtain the difference △Pt between the actual pressure at time t and the initial pressure by real-time measurement through a pressure sensor; Identify and obtain the highest harmonic order N to be compensated and the harmonic order n through an FFT spectrum analyzer; Obtain the actual temperature Ta by real-time monitoring through a temperature sensor; and upload them to the database together.

[0010] Optionally, the calculation processing module includes a pressure compensation resistance value algorithm unit, an adjusted resistance value algorithm unit, and a pressure sensitivity coefficient adjustment value algorithm unit.

[0011] Optionally, the pressure compensation resistance value algorithm unit is as follows: ; Where: Rsc represents the pressure compensation resistance value: V represents the output voltage; I represents the leakage current; △Pt represents the difference between the actual pressure at time t and the initial pressure; α represents the pressure sensitivity coefficient, which can be self-adjusted in the pressure compensation resistance value algorithm unit; β represents a positive and negative coefficient, with a value of 1 or -1, which can be self-adjusted in the pressure compensation resistance value algorithm unit. Specifically: It is the leakage current at the t-th time, and It+1 is the leakage current at the (t + 1)-th time; When It - It+1 > 0, β takes the value of 1, indicating that at this time, as the surface pressure of the object under test changes, the leakage current decreases, and the pressure change has a positive impact on the pressure compensation resistance value Rsc; When It - It+1 < 0, β takes the value of -1, indicating that at this time, as the surface pressure of the object under test changes, the leakage current increases, and the pressure change has a negative impact on the pressure compensation resistance value Rsc; In the formula calculation: This part obtains the basic resistance value by dividing the output voltage V of the high insulation resistance tester by the leakage current I. This value is the basis of the pressure compensation resistance value Rsc. When the output voltage V remains unchanged, as the leakage current I decreases, the calculated pressure compensation resistance value Rsc increases; This part is the adjustment item for calculating the pressure compensation resistance value Rsc due to the change in the surface pressure value of the object under test. Specifically: As the pressure increases, when the positive and negative coefficient β takes the value of 1, as the difference △Pt between the actual pressure and the initial pressure at time t increases, the calculated pressure compensation resistance value Rsc increases; As the pressure increases, when the positive and negative coefficient β takes the value of -1, as the difference △Pt between the actual pressure and the initial pressure at time t increases, the calculated pressure compensation resistance value Rsc decreases.

[0012] Optionally, the adjusted resistance value algorithm unit is as follows: ; Where: Rfa represents the adjusted resistance value; Rsc represents the pressure compensation resistance value; N represents the highest harmonic order to be compensated; n represents the harmonic order; Fna represents the actual frequency value of the nth harmonic; Fns represents the standard frequency value of the nth harmonic; Ts represents the standard temperature, which is the temperature in the ideal usage environment of the object under test; Ta represents the actual temperature; In the formula calculation: This part represents the ratio of the actual frequency to the standard frequency of the nth harmonic, This part multiplies the ratios of the actual frequency values to the standard frequency values of all harmonic orders to be compensated as a whole to quantify the comprehensive impact of all harmonic frequency offsets on the pressure compensation resistance value Rsc. As the harmonic frequency offset increases, the calculated value of this part is larger, The value of this part decreases, thereby reducing the calculated adjusted resistance value Rfa; This part normalizes the absolute difference between the actual temperature Ta and the standard temperature Ts to a value range of 0 to 1 through the standard temperature Ts. As the actual temperature Ta approaches the standard temperature Ts, the value of this part approaches 0, this part as a whole tends to 1, indicating that the ambient temperature at this time will not affect the calculation of the adjusted resistance value Rfa. As the deviation between the actual temperature Ta and the standard temperature Ts increases, the value of this part is less than 1, reducing the calculated adjusted resistance value Rfa.

[0013] Optionally, the algorithm unit for the pressure sensitivity coefficient adjustment value is as follows: ; Where: α t+1 represents the pressure sensitivity coefficient in the (t + 1)-th calculation; α t represents the pressure sensitivity coefficient in the t-th calculation; △Ta represents the absolute difference between the actual temperature Ta in the t-th calculation and the actual temperature Ta in the (t - 1)-th calculation; Rfa represents the adjusted resistance value; Rsc represents the pressure compensation resistance value; dt represents the measurement time interval; μ represents the integral gain coefficient, with a default value of 0.02; In the formula calculation: This part is represented by dividing the absolute difference △Ta between the actual temperature Ta in the t-th calculation and the actual temperature Ta in the (t - 1)-th calculation by the measurement time interval dt, which represents the actual temperature change rate in the resistance measurement. When the temperature changes rapidly, the value of this part increases, and the measured object will have fluctuations in insulation performance due to thermal expansion and contraction. At this time, the pressure sensitivity α is enhanced to offset the measurement deviation caused by the sudden temperature change; When this part > 1, the pressure compensation resistance value Rsc is lower than the adjusted resistance value Rfa, indicating insufficient current pressure compensation. In the (t + 1)-th calculation after pressure adjustment, α is increased to enhance the compensation intensity of Formula 1; When this part < 1, the pressure compensation resistance value Rsc is higher than the adjusted resistance value Rfa, indicating excessive pressure compensation. In the (t + 1)-th calculation after pressure adjustment, α is decreased to reduce the compensation intensity of Formula 1; This integral term continuously corrects the α value through the accumulation of historical deviations. Specifically: When this part continuously > 1, the integral value of this part increases positively, and α is gradually increased through the η gain coefficient to strengthen the compensation; When this part continuously < 1, the integral value of this part decreases negatively, and α is gradually decreased to suppress overcompensation.

[0014] Optionally, the insulation resistance tester further includes a high-precision frequency meter.

[0015] Optionally, the decoding preprocessing includes data cleaning and data standardization.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: First, in the test system of the insulation resistance tester of the present invention, through the mutual cooperation of three algorithm units, a core architecture of an insulation resistance test system is formed, comprehensively considering the output voltage V, leakage current I, and pressure change amount, and introducing a pressure sensitivity coefficient and positive and negative coefficients for automatic adjustment, and calculating the pressure compensation resistance value Rsc, which can more accurately reflect the insulation resistance characteristics of the object under test at a specific pressure. Compared with the range limitation of the traditional megohmmeter, the insulation resistance tester of the present invention can complete the measurement of the absorption ratio and polarization index of the measured object, so as to adapt to a wider range of test requirements.

[0017] Second, the insulation resistance tester of the present invention uses the adjusted resistance value algorithm unit in the test system to take the pressure compensation resistance value Rsc as an input parameter and calculates the adjusted resistance value Rfa through the frequency influence term and temperature deviation influence term, which can compensate for the harmonic frequency deviation and temperature change when measuring the resistance of the object, thereby reducing the interference of the comprehensive harmonic frequency deviation and temperature change on the resistance test result, and further improving the accuracy of the resistance test, so that the insulation resistance tester of the present invention can adapt to a wider range of test scenarios compared with the traditional megohmmeter. Whether it is high temperature or low temperature conditions, high frequency or low frequency conditions, this tester can provide reliable resistance value measurements.

[0018] III. The insulation resistance tester of the present invention can comprehensively calculate the pressure sensitivity coefficient α in the (t + 1)-th calculation based on the actual temperature change rate, the ratio of the adjusted resistance value Rfa to the pressure compensation resistance value Rsc, and the integral term of the historical deviation accumulation through the pressure sensitivity coefficient adjustment value algorithm unit in the test system, and form an intelligent closed-loop test system. In the resistance test of the insulation resistance tester, this dynamic adjustment method of parameters can avoid over-compensation or under-compensation problems caused by fixed parameters, can adjust the compensation intensity according to real-time conditions, ensure the accuracy and stability of pressure compensation, so that the test system of the insulation resistance tester can respond to changes in the external environment and working conditions in real time, and has stronger applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a flowchart of the test system in the insulation resistance tester; Figure 2 is a schematic diagram of the overall structure of the test system in the insulation resistance tester. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0021] Embodiment 1. Please refer to Figures 1 to 2 , the present invention provides an insulation resistance tester, including: a high insulation resistance tester, an FFT spectrum analyzer, a pressure generating device, a pressure sensor, a temperature sensor, and a test system; The test system specifically includes: A data collection module for collecting resistance measurement data, specifically including: Obtaining the output voltage V and leakage current I during resistance measurement through the insulation resistance tester; Real-time measuring the difference △Pt between the actual pressure and the initial pressure at time t through the pressure sensor; Identifying and obtaining the highest harmonic order N to be compensated and the harmonic order n through the FFT spectrum analyzer; Real-time monitoring and obtaining the actual temperature Ta through the temperature sensor; And uploading them to the database together; A data preprocessing module for decoding and preprocessing the data information in the database to obtain the parameters participating in the calculation in the calculation processing module; A calculation and processing module, which is used to input the parameters obtained after decoding and preprocessing into a pressure compensation resistance value algorithm unit to calculate the pressure compensation resistance value Rsc, and upload it to the database; Input the pressure compensation resistance value Rsc into the adjusted resistance value algorithm unit in the calculation and processing module, and calculate the adjusted resistance value Rfa by combining the frequency influence term and the temperature deviation influence, and upload it to the database; Input the adjusted resistance value Rfa and the pressure compensation resistance value Rsc into the pressure sensitivity coefficient adjustment value algorithm unit in the calculation and processing module to calculate the pressure sensitivity coefficient α in the (t + 1)-th calculation t+1 And upload it to the database.

[0022] In this embodiment: The test system in the insulation resistance tester of the present invention, through the mutual cooperation of three algorithm units, jointly constitutes the core architecture of an insulation resistance test system, comprehensively considers multiple factors such as the output voltage V, leakage current I, and pressure change amount, and introduces a pressure sensitivity coefficient and positive and negative coefficients for automatic adjustment, calculates the pressure compensation resistance value Rsc, and can more accurately reflect the insulation resistance characteristics of the object under test at a specific pressure. Compared with the range limitation of traditional megohmmeters (meggers), this insulation resistance tester can complete the measurement of the absorption ratio and polarization index of the measured object, so as to meet a wider range of test requirements.

[0023] And the adjusted resistance value algorithm unit in the test system uses the pressure compensation resistance value Rsc as an input parameter and can compensate for harmonic frequency deviation and temperature change through the frequency influence term and temperature deviation influence term, and calculate the adjusted resistance value Rfa, thereby reducing the interference of the comprehensive harmonic frequency deviation and temperature change on the resistance test result, improving the accuracy of the resistance test, and enabling the insulation resistance tester of the present invention to adapt to a wider range of test scenarios compared with traditional megohmmeters (meggers). Whether it is high temperature or low temperature conditions, this tester can provide reliable resistance value measurements.

[0024] Please refer to Figures 1 to 2 , the pressure compensation resistance value algorithm unit is as follows: ; Where: Rsc represents the pressure compensation resistance value: V represents the output voltage, which is obtained through a high insulation resistance tester; I represents the leakage current, which is obtained through a high insulation resistance tester; △Pt represents the difference between the actual pressure at time t and the initial pressure, which is measured in real time by a pressure sensor; α represents the pressure sensitivity coefficient, which can be self-adjusted in the pressure compensation resistance value algorithm unit; β represents positive and negative coefficients, with values of 1 or -1, and can be self-adjusted in the pressure compensation resistance value algorithm unit. Specifically: It is the leakage current at the t-th time, and It+1 is the leakage current at the (t + 1)-th time; When It - It+1 > 0, β takes the value of 1, indicating that at this time, as the surface pressure of the object under test changes, the leakage current decreases, and the pressure change has a positive impact on the pressure compensation resistance value Rsc; When It - It+1 < 0, β takes the value of -1, indicating that at this time, as the surface pressure of the object under test changes, the leakage current increases, and the pressure change has a negative impact on the pressure compensation resistance value Rsc; In the formula calculation: This part obtains the basic resistance value by dividing the output voltage V of the high-insulation resistance tester by the leakage current I. This value is the basis of the pressure compensation resistance value Rsc. When the output voltage V remains unchanged, as the leakage current I decreases, the calculated pressure compensation resistance value Rsc increases; This part is the adjustment item for the calculation of the pressure compensation resistance value Rsc due to the change in the surface pressure value of the object under test. Specifically: As the pressure increases, when the positive and negative coefficient β takes the value of 1, as the difference △Pt between the actual pressure and the initial pressure at the t-th moment increases, the calculated pressure compensation resistance value Rsc increases; As the pressure increases, when the positive and negative coefficient β takes the value of -1, as the difference △Pt between the actual pressure and the initial pressure at the t-th moment increases, the calculated pressure compensation resistance value Rsc decreases; In this embodiment: The pressure compensation resistance value algorithm unit calculates the pressure compensation resistance value Rsc by comprehensively considering multiple factors such as the output voltage V, the leakage current I, and the pressure change amount, and introducing the pressure sensitivity coefficient and the positive and negative coefficients for automatic adjustment. It can more accurately reflect the insulation resistance characteristics of the object under test at a specific pressure. Compared with the range limitation of traditional megohmmeters (meggers), this insulation resistance tester can adapt to a wider range of test requirements. For example: In the insulation test of underground cables, soil pressure changes may cause fluctuations in the leakage current. By adjusting the difference △Pt between the actual pressure and the initial pressure at the t-th moment in the pressure compensation resistance value algorithm unit, the present invention can simulate the soil pressure to more accurately measure the insulation resistance of underground cables.

[0025] Traditional megohmmeters require a hand-cranked generator to maintain a certain rotational speed to sustain a normal output voltage. The operation is cumbersome and inefficient. Moreover, manual operation is needed to read the pointer index, which is prone to errors caused by human factors. In contrast, the insulation resistance tester of the present invention adopts an electronic measurement and calculation method, which can reduce the generation of human errors, quickly complete the test and give the results, thus improving the test efficiency.

[0026] In summary, the insulation resistance tester of the present invention can meet the requirements of different objects to be measured and test environments, has strong versatility and adaptability, realizes automated measurement and calculation, improves the accuracy, efficiency and adaptability of the test, and reduces the generation of human errors.

[0027] Please refer to Figures 1 to 2 , and the adjusted resistance value algorithm unit is as follows: ; Where: Rfa represents the adjusted resistance value; Rsc represents the pressure compensation resistance value; N represents the highest harmonic order to be compensated, which is obtained by identifying through an FFT spectrum analyzer; n represents the harmonic order, which is obtained by identifying through an FFT spectrum analyzer; Regarding the highest harmonic order N to be compensated and the harmonic order n, specifically: By analyzing the spectrum of the test signal through an FFT spectrum analyzer, it is set that harmonics with an amplitude exceeding 0.5% of the fundamental wave need to be compensated. The harmonic order n to be compensated is automatically identified by the FFT analyzer, and the highest harmonic order N to be compensated is determined. This is a relatively mature existing technology in the field of harmonic analysis and will not be elaborated here; Fna represents the actual frequency value of the nth harmonic, and the actual frequencies of each harmonic are directly measured through a high-precision frequency meter (Agilent 53131A); Fns represents the standard frequency value of the nth harmonic, which is determined according to the material characteristics and is a fixed value. For example, in cable insulation testing, F1s = 50hz and F3s = 150hz; Ts represents the standard temperature, which is the temperature in the ideal usage environment of the object to be measured; Ta represents the actual temperature, which is obtained by real-time monitoring through a temperature sensor; In the formula calculation: This part represents the ratio of the actual frequency to the standard frequency of the nth harmonic, This part multiplies the ratios of the actual frequency values to the standard frequency values of all harmonic orders to be compensated as a whole, so as to quantify the comprehensive influence of all harmonic frequency offsets on the pressure compensation resistance value Rsc. As the harmonic frequency offset increases, the calculated value of this part is larger, the value of this part decreases, thereby reducing the calculated adjusted resistance value Rfa; As the temperature rises, the insulation resistance of the object under test will decrease. For example, in the case of cable insulation materials, when the temperature increases, the molecular thermal motion in the insulation material intensifies, the migration speed of ions and charges accelerates, resulting in an increase in the conduction current. Therefore, the insulation resistance of the cable insulation material will decrease; This part normalizes the absolute difference between the actual temperature Ta and the standard temperature Ts to a value range of 0 to 1 through the standard temperature Ts. As the actual temperature Ta gets closer to the standard temperature Ts, the value of this part is closer to 0, this part as a whole tends to 1, indicating that the ambient temperature at this time will not affect the calculation of the adjusted resistance value Rfa. As the deviation degree between the actual temperature Ta and the standard temperature Ts increases, the value of this part is less than 1, reducing the calculated adjusted resistance value Rfa; In this embodiment: The adjusted resistance value algorithm unit takes the pressure compensation resistance value Rsc as an input parameter and compensates for harmonic frequency deviation and temperature change through the frequency influence term and the temperature deviation influence term, and calculates the adjusted resistance value Rfa. It can reduce the interference of comprehensive harmonic frequency deviation and temperature change on the resistance test result, improve the test accuracy, and enable the insulation resistance tester of the present invention to adapt to a wider range of test scenarios compared with traditional megohmmeters (meggers). Whether in high temperature or low temperature conditions, this tester can provide reliable resistance value measurements.

[0028] And because the insulation resistance tester of the present invention can monitor parameters such as the pressure, frequency, and temperature of the object under test in real time and calculate the resistance value in real time, it can timely detect the abnormal state of the object under test, which is of great significance for some occasions with high requirements for insulation performance (such as power equipment cabinets, switch cabinets, etc.). It can ensure the normal operation of the equipment and the safety of personnel, and improve the safety of the insulation resistance tester.

[0029] Please refer to Figures 1 to 2 , the pressure sensitivity coefficient adjustment value algorithm unit is as follows: ; Where: α t+1 represents the pressure sensitivity coefficient in the (t + 1)-th calculation; α t represents the pressure sensitivity coefficient in the t-th calculation; △Ta represents the absolute difference between the actual temperature Ta in the t-th calculation and the actual temperature Ta in the (t - 1)-th calculation; Rfa represents the adjusted resistance value; Rsc represents the pressure compensation resistance value; dt represents the measurement time interval. The smaller the measurement time interval dt, the higher the integration accuracy, but the computational load increases; μ represents the integration gain coefficient, and the default value is 0.02; In the formula calculation: This part is obtained by dividing the absolute difference △Ta between the actual temperature Ta in the t-th calculation and the actual temperature Ta in the (t - 1)-th calculation by the measurement time interval dt, representing the actual temperature change rate in resistance measurement. When the temperature changes rapidly, the value of this part increases, and the measured object will have fluctuations in insulation performance due to thermal expansion and contraction. At this time, the pressure sensitivity α is enhanced to offset the measurement deviation caused by the sudden temperature change; When this part > 1, the pressure compensation resistance value Rsc is lower than the adjusted resistance value Rfa, indicating insufficient current pressure compensation. In the (t + 1)-th calculation after pressure adjustment, α is increased to enhance the compensation intensity of Formula 1; When this part < 1, the pressure compensation resistance value Rsc is higher than the adjusted resistance value Rfa, indicating excessive pressure compensation. In the (t + 1)-th calculation after pressure adjustment, α is decreased to reduce the compensation intensity of Formula 1; This integral term continuously corrects the value of α through the accumulation of historical deviations. Specifically: When this part continuously > 1, the integral value of this part increases positively, and α is gradually increased through the η gain coefficient to strengthen the compensation; When this part continuously < 1, the integral value of this part increases negatively, and α is gradually decreased to inhibit overcompensation; In this embodiment: The pressure sensitivity coefficient adjustment value algorithm unit can comprehensively calculate the value of the pressure sensitivity coefficient in the (t + 1)-th calculation based on the actual temperature change rate, the ratio of the adjusted resistance value Rfa to the pressure compensation resistance value Rsc, and the integral term of the historical deviation accumulation, so as to form an intelligent closed-loop test system. In the resistance test of the insulation resistance tester, this dynamic adjustment method for the dynamic adjustment of the pressure sensitivity coefficient α can avoid over-compensation or under-compensation problems caused by fixed parameters, can adjust the compensation intensity according to the real-time situation, ensure the accuracy and stability of the pressure compensation, so that the test system can respond to changes in the external environment and working conditions in real time. In practical applications, the system is often affected by various uncertainties and external interferences. The method of dynamically adjusting parameters can enhance the system's resistance to these factors and improve the robustness and reliability of the test system.

[0030] By dynamically adjusting the pressure sensitivity coefficient α, the system can more precisely control the pressure and reduce errors and fluctuations during resistance measurement, which is particularly important for application scenarios that require high-precision pressure control.

[0031] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Insulation resistance tester, characterized in that, It includes a high insulation resistance tester, an FFT spectrum analyzer, a pressure generating device, a pressure sensor, a temperature sensor, and a test system; The test system specifically includes: A data collection module for collecting resistance measurement data; A data preprocessing module for decoding and preprocessing the data information in the database to obtain the parameters participating in the calculation in the calculation processing module; A calculation processing module for inputting the parameters obtained after decoding and preprocessing into the pressure compensation resistance value algorithm unit to calculate the pressure compensation resistance value Rsc and uploading it to the database; Input the pressure compensation resistance value Rsc into the adjusted resistance value algorithm unit in the calculation processing module to calculate the adjusted resistance value Rfa by combining the frequency influence term and the temperature deviation influence, and upload it to the database; The adjusted resistance value Rfa and the pressure compensation resistance value Rsc are input into the pressure sensitivity coefficient adjustment value algorithm unit in the calculation and processing module to calculate the pressure sensitivity coefficient α in the (t + 1)-th calculation. t+1 And it is uploaded to the database.

2. The insulation resistance tester according to claim 1, characterized in that: The collection of resistance measurement data specifically includes: Obtain the output voltage V and leakage current I during resistance measurement through the insulation resistance tester; Obtain the difference △Pt between the actual pressure and the initial pressure at time t through real-time measurement by the pressure sensor; Identify and obtain the highest harmonic order N to be compensated and the harmonic order n through the FFT spectrum analyzer; Obtain the actual temperature Ta through real-time monitoring by the temperature sensor; And upload them to the database together.

3. The insulation resistance tester according to claim 1, characterized in that: The calculation processing module includes a pressure compensation resistance value algorithm unit, an adjusted resistance value algorithm unit, and a pressure sensitivity coefficient adjustment value algorithm unit.

4. The insulation resistance tester according to claim 3, characterized in that: The pressure compensation resistance value algorithm unit is as follows: ； Where: Rsc represents the pressure compensation resistance value: V represents the output voltage; I represents the leakage current; △Pt represents the difference between the actual pressure and the initial pressure at time t; α represents the pressure sensitivity coefficient, which can be self-adjusted in the pressure compensation resistance value algorithm unit; β represents the positive and negative coefficient, with a value of 1 or -1, which can be self-adjusted in the pressure compensation resistance value algorithm unit. Specifically: It is the leakage current at the t-th time, and It+1 is the leakage current at the (t + 1)-th time; When It - It+1 > 0, β takes the value of 1, indicating that at this time, as the surface pressure of the object under test changes, the leakage current decreases, and the pressure change has a positive impact on the pressure compensation resistance value Rsc; When It - It+1 < 0, β takes the value of -1, indicating that at this time, as the surface pressure of the object under test changes, the leakage current increases, and the pressure change has a negative impact on the pressure compensation resistance value Rsc; In the formula calculation: This part obtains the basic resistance value by dividing the output voltage V of the high insulation resistance tester by the leakage current I. This value is the basis for the pressure compensation resistance value Rsc. When the output voltage V remains unchanged, as the leakage current I decreases, the calculated pressure compensation resistance value Rsc increases; This part is the adjustment term for calculating the pressure compensation resistance value Rsc due to the change in the surface pressure value of the object under test. Specifically: As the pressure increases, when the positive and negative coefficient β takes the value of 1, as the difference △Pt between the actual pressure and the initial pressure at time t increases, the calculated pressure compensation resistance value Rsc increases; As the pressure increases, when the positive and negative coefficient β takes the value of -1, as the difference △Pt between the actual pressure and the initial pressure at time t increases, the calculated pressure compensation resistance value Rsc decreases.

5. The insulation resistance tester according to claim 4, wherein: The adjusted resistance value algorithm unit is as follows: ； Where: Rfa represents the adjusted resistance value; Rsc represents the pressure compensation resistance value; N represents the highest harmonic order to be compensated; n represents the harmonic order; Fna represents the actual frequency value of the n-th harmonic; Fns represents the standard frequency value of the n-th harmonic; Ts represents the standard temperature, which is the temperature in the ideal usage environment of the object under test; Ta represents the actual temperature; In the formula calculation: This part represents the ratio of the actual frequency of the nth harmonic to the standard frequency, This part multiplies the ratios of the actual frequency values to the standard frequency values of all harmonic orders to be compensated together to quantify the comprehensive influence of all harmonic frequency offsets on the pressure compensation resistance value Rsc. As the harmonic frequency offset increases, the calculated value of this part is larger, the value of this part decreases, thereby reducing the calculated adjusted resistance value Rfa; This part normalizes the absolute difference between the actual temperature Ta and the standard temperature Ts to a value range of 0 to 1 through the standard temperature Ts. As the actual temperature Ta gets closer to the standard temperature Ts, the value of this part gets closer to 0, this part as a whole tends to 1, indicating that the ambient temperature at this time will not affect the calculation of the adjusted resistance value Rfa. As the deviation between the actual temperature Ta and the standard temperature Ts becomes larger, the value of this part is less than 1, reducing the calculated adjusted resistance value Rfa.

6. The insulation resistance tester according to claim 5, wherein: The algorithm unit for the pressure sensitivity coefficient adjustment value is as follows: ； Where: α t+1 represents the pressure sensitivity coefficient in the (t + 1)-th calculation; α t represents the pressure sensitivity coefficient in the t-th calculation; △Ta represents the absolute difference between the actual temperature Ta in the t-th calculation and the actual temperature Ta in the (t - 1)-th calculation; Rfa represents the adjusted resistance value; Rsc represents the pressure compensation resistance value; dt represents the measurement time interval; μ represents the integral gain coefficient, and the default value is 0.02; In the formula calculation: This part represents the actual temperature change rate in resistance measurement by dividing the absolute difference ΔTa between the actual temperature Ta in the t-th calculation and the actual temperature Ta in the (t - 1)-th calculation by the measurement time interval dt. When the temperature changes rapidly, the value of this part increases, and the measured object will cause fluctuations in insulation performance due to thermal expansion and contraction. At this time, the pressure sensitivity α is enhanced to offset the measurement deviation caused by the sudden temperature change; When When this part > 1, the pressure compensation resistance value Rsc is lower than the adjusted resistance value Rfa, indicating insufficient current pressure compensation. In the (t + 1)-th calculation after pressure adjustment, increase α to enhance the compensation intensity of Formula 1; When When this part < 1, the pressure compensation resistance value Rsc is higher than the adjusted resistance value Rfa, indicating excessive pressure compensation. In the (t + 1)-th calculation after pressure adjustment, α is reduced to decrease the compensation intensity of Formula 1; This integral term continuously corrects the α value through the accumulation of historical deviations, specifically: When this part lasts > 1 the integral value of this part increases positively, gradually increasing α through the η gain coefficient to strengthen the compensation; When When this part lasts < 1, the integral value of this part increases negatively, gradually reduces α, and suppresses overcompensation.

7. The insulation resistance tester according to claim 1, characterized in that: The insulation resistance tester further includes a high-precision frequency meter.

8. The insulation resistance tester according to claim 1, characterized in that, The decoding preprocessing includes data cleaning and data standardization.

Images