Low-voltage switch electric life test device and low-voltage switch residual life prediction method

Abstract

The invention relates to the technical field of low-voltage switch life test, and provides a low-voltage switch electrical life test device and a low-voltage switch residual life prediction method, and the device comprises the steps: an upper computer module sends a control command, and carries out the analysis and prediction of the residual electrical life of a tested low-voltage switch according to the collected electrical life characteristic parameters of the tested low-voltage switch; the single-chip microcomputer module receives the control command to drive the control circuit module to act, and the tested low-voltage switch is connected to the circuit and tested. The data acquisition circuit module acquires voltage and current between the contacts of the detected low-voltage switch; the signal conditioning circuit module converts the data into a signal required by the input of an A / D module in the single chip microcomputer module; the load module is formed by connecting a resistor and an air-core reactor in series; the protection circuit module carries out overvoltage and overcurrent protection on the whole test device. And the display and printing module displays the data information processed by the upper computer module in real time. Characteristic parameters can be extracted conveniently and accurately, and service life prediction is simple and reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of low-voltage switch life test, and in particular to a low-voltage switch electrical life test device and a low-voltage switch remaining life prediction method. Background Art

[0002] As a power distribution appliance with many users and wide application fields, low-voltage switches are indispensable switchgear in low-voltage power distribution systems. They protect electrical equipment from short circuits, overvoltages, undervoltages and other factors. Once a failure occurs, the loss is immeasurable. Therefore, it is of great significance to predict the electrical life of low-voltage switches.

[0003] At present, the prediction of the electrical life of low-voltage switches is mainly based on a large amount of reliability test data, mainly using surface roughness method, dual variable prediction method based on overtravel time and pull-in time, segmented current weighted accumulation, effective contact distance method, mass loss method, signal feature extraction method, etc. The requirements for the electrical life test device of low-voltage switches are high, and complex test equipment is needed to measure the corresponding parameters, and the test cycle is long. Summary of the invention

[0004] The purpose of the present invention is to solve at least one technical problem in the background technology and to provide a low-voltage switch electrical life test device and a low-voltage switch remaining life prediction method.

[0005] To achieve the above object, the present invention provides a low-voltage switch life test device, comprising: a control circuit module, a data acquisition circuit module, a signal conditioning circuit module, a single-chip computer module, a protection circuit module, a host computer module, a load module and a display and printing module;

[0006] The host computer module receives and processes external signals and issues control commands, and analyzes and predicts the remaining electrical life of the low-voltage switch under test based on the collected electrical life characteristic parameters;

[0007] The single chip microcomputer module receives the control command to drive the control circuit module to operate, connect the low voltage switch to the circuit and perform the test;

[0008] The data acquisition circuit module collects the voltage and current between the contacts of the low-voltage switch under test through a voltage transformer and a current transformer;

[0009] The signal conditioning circuit module converts the data collected by the data acquisition circuit module into the signal required by the A / D module in the single-chip microcomputer module;

[0010] The load module is formed by connecting a resistor and an air-core reactor in series, and is adjusted according to the test parameters;

[0011] The protection circuit module provides overvoltage and overcurrent protection to the entire test device;

[0012] The display and printing module displays the data information processed by the host computer module in real time.

[0013] According to one aspect of the present invention, the control circuit module controls the on and off of the solid-state relay coil, so that the solid-state relay works according to a specified action sequence, so that the low-voltage switch under test is automatically connected to the circuit, and the electrical life-related parameters of the low-voltage switch test product are obtained.

[0014] According to one aspect of the present invention, the host computer module outputs a trigger digital pulse with adjustable frequency and duty cycle to trigger a set trigger circuit;

[0015] The host computer module is based on the Windows operating system and uses Labview software to establish a human-computer interaction system, and realizes real-time acquisition and processing of contact voltage and contact current signals, data storage, and parameter setting;

[0016] The host computer module communicates with the single-chip computer module through the serial port to realize the automatic opening and closing control of the low-voltage switch under test and the interaction of test data. At the same time, the data can be directly stored in Excel format.

[0017] According to one aspect of the present invention, the data acquisition circuit module collects the coil voltage and current of the low-voltage switch under test, and the contact voltage and current during opening and closing.

[0018] According to one aspect of the present invention, the signal conditioning circuit module uses an AD acquisition chip to collect signals in the data acquisition circuit module, selects a bipolar AD acquisition chip to sample AC voltage and current signals, and inputs them into the single-chip microcomputer module to calculate contact characteristic parameters.

[0019] Furthermore, in order to achieve the above-mentioned purpose, the present invention also provides a method for predicting the remaining life of a low-voltage switch based on the above-mentioned low-voltage switch electrical life test device, comprising:

[0020] Set the test parameters of the low-voltage switch under test in the host computer module;

[0021] The host computer module issues a control command, and the single-chip microcomputer module drives the control circuit module to operate after receiving the control command, connects the low-voltage switch to the circuit and performs the test according to the set test parameters;

[0022] The voltage and current between the contacts of the low-voltage switch under test are collected through the data acquisition circuit module, and the voltage and current are converted into data through the signal conditioning circuit module. After the conversion, the data is exchanged to the host computer module through the single-chip microcomputer module;

[0023] The host computer module calculates the contact resistance based on the received voltage and current data, and then extracts the characteristic parameters of the contact resistance after denoising using wavelet transform;

[0024] In the host computer module, the probability statistics method is used to automatically analyze the processed contact resistance parameters, and the hypothesis test of the contact resistance characteristic parameters is carried out according to the typical probability distribution to determine the probability distribution function type of the contact resistance of the low-voltage switch under test;

[0025] According to the determined probability distribution function type, a model of the relationship between the mean and variance of contact resistance and the electrical life is established. At the same time, the univariate linear regression method is used to perform regression analysis on the data, and the sum of square errors of each function is calculated. The function relationship with the smallest sum of square errors is taken as the optimal relationship model between the mean, variance and electrical life, thereby realizing the remaining electrical life prediction of the low-voltage switch.

[0026] According to one aspect of the present invention, the host computer module calculates the contact resistance according to the received voltage and current data, including:

[0027] Read the contact voltage data during the closing process of the low-voltage switch and calculate the average value of the contact voltage during the closing process;

[0028] Read the contact current data during the closing process of the low-voltage switch and calculate the average value of the contact current during the closing process;

[0029] Calculate the contact resistance using the following formula:

[0030] R j =(U*a) / (I*b);

[0031] Among them, U is the average value of the contact voltage during the closing process, I is the average value of the contact current during the closing process, and a and b are acquisition proportional coefficients.

[0032] According to one aspect of the present invention, the method of performing hypothesis testing on the characteristic parameters of the contact resistance according to the typical probability distribution to determine the probability distribution function type of the contact resistance of the low-voltage switch under test includes:

[0033] According to the typical probability distribution, the KS test method is used to determine the probability distribution function type of the first 1000 contact resistances of the tested low-voltage switch;

[0034] A KS test is performed based on the calculated contact resistance value. Under the condition of a significance level of 0.05, it is determined which probability distribution the contact resistance obeys. The probability distribution includes normal distribution, extreme value distribution, exponential distribution, Γ distribution, lognormal distribution, Poisson distribution, Rayleigh distribution, Weibull distribution and β distribution.

[0035] According to one aspect of the present invention, a model is established for the relationship between the mean and variance of the contact resistance and the electrical life according to the determined type of probability distribution function. At the same time, the unary linear regression method is used to perform regression analysis on the data, calculate the sum of squared errors of each function, and take the function relationship with the minimum sum of squared errors as the optimal relationship model between the mean, variance and electrical life, so as to realize the prediction of the remaining electrical life of the low-voltage switch as follows:

[0036] According to the determined probability distribution type, the mean and variance of the contact resistance in the first 1000 times are respectively related to the electrical life, including the monotonic function relationships of linear function, exponential function, logarithmic function and power function. Calculate the SSE of each function, determine the optimal relationship model, and then realize the prediction of the remaining electrical life of the low-voltage switch.

[0037] According to the solution of the present invention, the hardware part of the present invention adopts a modular design, and each parameter module has good compatibility. The software part is designed for the human-computer interaction interface using Labview based on the Windows operating system. After wavelet transform denoising of the collected data, the contact resistance is calculated, and a remaining electrical life model is established according to the probability distribution of the contact resistance. Moreover, the life test of the low-voltage switch is fully automatic control, without manual intervention, the required test period is short, the extraction of electrical life characteristic parameters is convenient and accurate, and the prediction method is simple and reliable.

[0038] According to the above solution of the present invention, the present invention takes the upper computer as the control core, and automatically completes the electrical life test with reference to the electrical life test method. It has the advantages of simple operation, high measurement accuracy, stable operation, full automation, etc. During the test process, the opening and closing operations of the test sample can be automatically controlled, and the contact state of the test sample can be monitored in real time. The change trend of the voltage and current data between the contacts during the test is analyzed, and the electrical life related parameters are automatically recorded. The test process is simple and convenient. It is proposed to predict the electrical life by using the parameters of the low-voltage switch based on the contact resistance, perform hypothesis testing on it according to the typical probability distribution, establish a relationship model between the contact resistance and the life after determining the distribution law, and predict the electrical life of the low-voltage switch through the model. The electrical life device and the remaining life prediction method designed by the present invention have a short required test period, and the extraction of characteristic parameters is convenient and accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematically showing the structural layout block diagram of the electrical life test device of the low-voltage switch according to an embodiment of the present invention;

[0040] Figure 2 Schematically showing the flowchart of the remaining life prediction method of the low-voltage switch according to an embodiment of the present invention;

[0041] Figure 3Schematically represent a flowchart for calculating contact resistance according to an embodiment of the present invention. Detailed implementation manners

[0042] The content of the present invention will now be described with reference to exemplary embodiments. It should be understood that the described embodiments are only for enabling those of ordinary skill in the art to better understand and thus implement the content of the present invention, rather than implying any limitation on the scope of the present invention.

[0043] As used herein, the term "comprising" and its variants are to be construed as open-ended terms meaning "including but not limited to". The term "based on" is to be construed as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be construed as "at least one embodiment".

[0044] Figure 1 Schematically represent a structural layout block diagram of a low-voltage switch electrical life test device according to an embodiment of the present invention. As Figure 1 shown, in this embodiment, the low-voltage switch electrical life test device includes: a control circuit module 1, a data acquisition circuit module 2, a signal conditioning circuit module 3, a single-chip microcomputer module 4, a protection circuit module 5, a host computer module 6, a load module 7, and a display and printing module 8;

[0045] The host computer module 6 receives and processes external signals and issues control commands, and at the same time analyzes and predicts the remaining electrical life according to the collected electrical life characteristic parameters of the measured low-voltage switch;

[0046] The single-chip microcomputer module 4 receives the control command to drive the control circuit module 1 to act, connects the measured low-voltage switch 9 to the circuit and conducts the test;

[0047] The data acquisition circuit module 2 collects the voltage and current between the contacts of the measured low-voltage switch 9 through a voltage transformer and a current transformer;

[0048] The signal conditioning circuit module 3 converts the data collected by the data acquisition circuit module 2 into a signal required for input to the A / D module in the single-chip microcomputer module 4;

[0049] The load module 7 is formed by connecting a resistor and an air-core reactor in series, and is adjusted according to the test parameters;

[0050] The protection circuit module 5 provides overvoltage and overcurrent protection for the entire test device;

[0051] The display and printing module 8 displays the data information processed by the host computer module 6 in real time.

[0052] Furthermore, according to an embodiment of the present invention, the control circuit module 1 controls the on and off of the solid-state relay coil, so that the solid-state relay works according to a prescribed action sequence, so that the low-voltage switch under test is automatically connected to the circuit, and the electrical life-related parameters of the low-voltage switch test product are obtained.

[0053] Further, according to an embodiment of the present invention, the host computer module 6 outputs a trigger digital pulse with adjustable frequency and duty cycle to trigger a set trigger circuit;

[0054] In this embodiment, the host computer module 6 is based on the Windows operating system, uses Labview software to establish a human-computer interaction system, and realizes real-time acquisition and processing of contact voltage and contact current signals, data storage, parameter setting, and realizes functions such as automatic control, data analysis, and life prediction;

[0055] The host computer module 6 communicates with the single-chip computer module 4 through the serial port to realize the automatic opening and closing control of the low-voltage switch under test and the test data interaction, and the data can be directly stored in Excel format.

[0056] In this embodiment, in order to ensure the continuity and real-time performance of the signal, the test adopts continuous sampling. The test parameters are set first. According to the set parameters, the digital pulses generated by the host computer module 6 are continuously sent to the counter, and the counter then sends the digital pulses to the relay to control the relay action. The I / O port of the single-chip microcomputer module 4 outputs a digital signal to drive the IGBT on and off, thereby controlling the power on and off of the coil to achieve the automatic control function. The power supply voltage of the relay coil loop is AC 220V. In order to protect the test device, an optocoupler is used for isolation protection. At the same time, the main control circuit can automatically switch according to the test type, and the rated voltage of the control circuit of the low-voltage switch under test is switched. Low-voltage switches with multiple rated voltages can be tested.

[0057] In this embodiment, data needs to be collected in real time and continuously. The single-chip microcomputer module 4 stores the data in a cache area after collecting the data once. Therefore, the producer / consumer mode in the software is adopted to generate a cache area for temporarily storing data to avoid incomplete data due to test time during collection and reading.

[0058] Further, according to an embodiment of the present invention, the data acquisition circuit module 2 collects the coil voltage and current of the low-voltage switch under test, and the contact voltage and current when the switch is opened and closed. The closing time (contact closure) of the low-voltage switch is short, and the contact voltage drop is at the mV level, so a high-precision sensor is used to collect signals, and after the collection is completed, the data is passed to the signal conditioning circuit module.

[0059] In this embodiment, a voltage sensor is used to measure the AC voltage across the contacts of the low-voltage switch under test in real time, and a current sensor is used to measure the current flowing through the contacts of the low-voltage switch under test. At the same time, the collected signal is converted into a voltage signal, and a voltage follower is used to follow it and then perform RC low-pass filtering to eliminate high-order harmonic interference.

[0060] Further, according to one embodiment of the present invention, the signal conditioning circuit module 3 uses an AD acquisition chip to collect signals in the data acquisition circuit module, selects a bipolar AD acquisition chip to sample AC voltage and current signals, and inputs the signals into the single-chip microcomputer module to calculate contact characteristic parameters.

[0061] Further, according to an embodiment of the present invention, the load module 7 is the load of the low-voltage switch under test, ensuring that the low-voltage switch under test can complete the test under different power factors according to the set type. In this embodiment, an adjustable high-precision cement resistor is used in series with an air-core reactor as the load of the low-voltage switch under test.

[0062] Furthermore, according to one embodiment of the present invention, the protection circuit module 5 implements overvoltage and overcurrent protection for the test device. In this embodiment, the current of the main circuit is detected. If the actual current exceeds 2 times the set current value for more than 50ms, the power supply of the main circuit is cut off to ensure the reliability of the test device.

[0063] Further, according to one embodiment of the present invention, the display and printing module 8 is used to display the test data in real time, such as the changes in voltage and current waveforms during the test, the voltage value at the break when connected and disconnected, the current value at the break, and the voltage value and current value of the coil.

[0064] Furthermore, in order to achieve the above-mentioned purpose, the present invention also provides a method for predicting the remaining life of a low-voltage switch based on the above-mentioned low-voltage switch electrical life test device, such as Figure 2 As shown, including:

[0065] The test parameters of the low-voltage switch under test are set in the host computer module 6, including the test type, power factor, operating frequency, number of test cycles, power-on time, etc., so as to start the calculation of contact resistance and the prediction of remaining electrical life;

[0066] The host computer module 6 issues a control command, and the single-chip computer module 4 drives the control circuit module 1 to operate after receiving the control command, connects the low-voltage switch 9 to the circuit and performs the test according to the set test parameters;

[0067] The voltage and current between the contacts of the low-voltage switch 9 under test are collected through the data acquisition circuit module 2, and the voltage and current are converted into data through the signal conditioning circuit module 3. After the conversion, the data is exchanged to the host computer module 6 through the single-chip microcomputer module 4;

[0068] The upper computer module 6 calculates the contact resistance according to the received voltage and current data, selects the contact resistance calculation results of the first 1000 openings and closings of the low-voltage switch under test, and then extracts characteristic parameters after denoising the contact resistance using wavelet transform. The contact resistance after denoising eliminates singular points in the data, making the data more accurate and avoiding errors introduced by test conditions and parameter calculations;

[0069] In the upper computer module 6, a probability statistics method is used to automatically analyze the processed contact resistance parameters, and a hypothesis test is performed on the contact resistance characteristic parameters according to a typical probability distribution to determine the probability distribution function type of the contact resistance of the low-voltage switch under test;

[0070] According to the determined probability distribution function type, a model of the relationship between the mean and variance of contact resistance and the electrical life is established. At the same time, the univariate linear regression method is used to perform regression analysis on the data, and the sum of square errors of each function is calculated. The function relationship with the smallest sum of square errors is taken as the optimal relationship model between the mean, variance and electrical life, thereby realizing the remaining electrical life prediction of the low-voltage switch.

[0071] Further, according to one embodiment of the present invention, Figure 3 As shown, the upper computer module 6 calculates the contact resistance according to the received voltage and current data, including:

[0072] Read the contact voltage data during the closing process of the low-voltage switch and calculate the average value of the contact voltage during the closing process;

[0073] Read the contact current data during the closing process of the low-voltage switch and calculate the average value of the contact current during the closing process;

[0074] Calculate the contact resistance using the following formula:

[0075] R j =(U*a) / (I*b);

[0076] Among them, U is the average value of the contact voltage during the closing process, I is the average value of the contact current during the closing process, and a and b are acquisition proportional coefficients.

[0077] In this embodiment, a=400 / 3, b=250.

[0078] Further, according to an embodiment of the present invention, a hypothesis test is performed on the characteristic parameters of the contact resistance according to a typical probability distribution to determine the probability distribution function type of the contact resistance of the measured low-voltage switch, including:

[0079] According to the typical probability distribution, the KS test method is used to determine the probability distribution function type of the first 1000 contact resistances of the tested low-voltage switch;

[0080] A KS test is performed based on the calculated contact resistance value. Under the condition of a significance level of 0.05, it is determined which probability distribution the contact resistance obeys. The probability distribution includes normal distribution, extreme value distribution, exponential distribution, Γ distribution, lognormal distribution, Poisson distribution, Rayleigh distribution, Weibull distribution and β distribution.

[0081] In this embodiment, the statistic of the KS test is:

[0082] It means that under the assumption that the distribution function F n (x i-1 )=F(x i ) under the condition that F n (x i-1 )-F(x i ), if the null hypothesis holds, then Z should be very small.

[0083] Further, according to an embodiment of the present invention, a model of the relationship between the mean and variance of the contact resistance and the electrical life is established according to the determined probability distribution function type, and a univariate linear regression method is used to perform regression analysis on the data, and the sum of square errors of each function is calculated. The function relationship with the minimum sum of square errors is used as the optimal relationship model between the mean, variance and electrical life, thereby realizing the prediction of the remaining electrical life of the low-voltage switch as follows:

[0084] According to the determined probability distribution type, the mean and variance of the first 1000 contact resistances are respectively related to the electrical life, including the monotonic function relationship of linear function, exponential function, logarithmic function, and power function. The SSE (sum of squared errors) of each function is calculated to determine the optimal relationship model, thereby realizing the remaining electrical life prediction of the low-voltage switch.

[0085] According to the above scheme of the present invention, the hardware part of the present invention adopts modular design, and each parameter module has good compatibility. The software part adopts Labview for human-computer interaction interface design based on Windows operating system, calculates the contact resistance after wavelet transform denoising on the collected data, and establishes the remaining electrical life model according to the probability distribution of the contact resistance. The life test of the low-voltage switch is fully automatically controlled without manual intervention, the required test cycle is short, the extraction of electrical life characteristic parameters is convenient and accurate, and the prediction method is simple and reliable.

[0086] According to the above scheme of the present invention, the present invention uses the host computer as the control core, and refers to the electrical life test method to automatically complete the electrical life test. It has the advantages of simple operation, high measurement accuracy, stable operation, and full automation. During the test, the opening and closing operations of the test product can be automatically controlled, and the contact state of the test product can be monitored in real time, the change trend of the voltage and current data between the contacts during the test is analyzed, and the parameters related to the electrical life are automatically recorded. The test process is simple and convenient. It is proposed to use low-voltage switch parameters based on contact resistance to predict the electrical life, conduct hypothesis testing on it according to typical probability distribution, establish a relationship model between contact resistance and life after determining the distribution law, and use the model to predict the electrical life of the low-voltage switch. The electrical life device and the remaining life prediction method designed by the present invention require a short test cycle, and the extraction of characteristic parameters is convenient and accurate.

[0087] Those skilled in the art will appreciate that the modules and algorithm steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0088] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices and equipment can refer to the corresponding processes in the aforementioned method implementation methods, and will not be repeated here.

[0089] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0090] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed on multiple network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the embodiments of the present invention.

[0091] In addition, each functional module in the embodiment of the present invention may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module.

[0092] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the energy-saving signal sending / receiving method of each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, ROM, RAM, magnetic disks, or optical disks.

[0093] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in this application (but not limited to) by each other.

[0094] It should be understood that the size of the serial numbers of each step in the content of the invention and the implementation methods of the present invention does not absolutely mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the implementation methods of the present invention.

Claims

1. Low voltage switch life test device, characterized in that: include: Control circuit module, data acquisition circuit module, signal conditioning circuit module, single chip computer module, protection circuit module, host computer module, load module and display and printing module; The host computer module receives and processes external signals and issues control commands, and analyzes and predicts the remaining electrical life of the low-voltage switch under test based on the collected electrical life characteristic parameters; The single chip microcomputer module receives the control command to drive the control circuit module to operate, connect the low voltage switch to the circuit and perform the test; The data acquisition circuit module collects the voltage and current between the contacts of the low-voltage switch under test through a voltage transformer and a current transformer; The signal conditioning circuit module converts the data collected by the data acquisition circuit module into the signal required by the A / D module in the single-chip microcomputer module; The load module is formed by connecting a resistor and an air-core reactor in series, and is adjusted according to the test parameters; The protection circuit module provides overvoltage and overcurrent protection to the entire test device; The display and printing module displays the data information processed by the host computer module in real time.

2. The low voltage switch electrical life test device according to claim 1, characterized in that: The control circuit module controls the on and off of the solid-state relay coil, so that the solid-state relay works according to a specified action sequence, so that the low-voltage switch under test is automatically connected to the circuit, and the electrical life-related parameters of the low-voltage switch test product are obtained.

3. The low voltage switch electrical life test device according to claim 1, characterized in that: The host computer module outputs a trigger digital pulse with adjustable frequency and duty cycle to trigger the set trigger circuit; The host computer module is based on the Windows operating system and uses Labview software to establish a human-computer interaction system, and realizes real-time acquisition and processing of contact voltage and contact current signals, data storage, and parameter setting; The host computer module communicates with the single-chip computer module through the serial port to realize the automatic opening and closing control of the low-voltage switch under test and the interaction of test data. At the same time, the data can be directly stored in Excel format.

4. The low voltage switch electrical life test device according to claim 1, characterized in that: The data acquisition circuit module collects the coil voltage and current of the low-voltage switch under test, and the contact voltage and current during opening and closing.

5. The low voltage switch life test device according to any one of claims 1 to 4, characterized in that: The signal conditioning circuit module uses an AD acquisition chip to acquire signals in the data acquisition circuit module, selects a bipolar AD acquisition chip to sample AC voltage and current signals, and inputs the signals into the single-chip microcomputer module to calculate contact characteristic parameters.

6. A method for predicting the remaining life of a low-voltage switch implemented based on the low-voltage switch electrical life test device according to any one of claims 1 to 5, characterized in that: include: Set the test parameters of the low-voltage switch under test in the host computer module; The host computer module issues a control command, and the single-chip microcomputer module drives the control circuit module to operate after receiving the control command, connects the low-voltage switch to the circuit and performs the test according to the set test parameters; The voltage and current between the contacts of the low-voltage switch under test are collected through the data acquisition circuit module, and the voltage and current are converted into data through the signal conditioning circuit module. After the conversion, the data is exchanged to the host computer module through the single-chip microcomputer module; The host computer module calculates the contact resistance based on the received voltage and current data, and then extracts the characteristic parameters of the contact resistance after denoising using wavelet transform; In the host computer module, the probability statistics method is used to automatically analyze the processed contact resistance parameters, and the hypothesis test of the contact resistance characteristic parameters is carried out according to the typical probability distribution to determine the probability distribution function type of the contact resistance of the low-voltage switch under test; According to the determined probability distribution function type, a model of the relationship between the mean and variance of contact resistance and the electrical life is established. At the same time, the univariate linear regression method is used to perform regression analysis on the data, and the sum of square errors of each function is calculated. The function relationship with the smallest sum of square errors is taken as the optimal relationship model between the mean, variance and electrical life, thereby realizing the remaining electrical life prediction of the low-voltage switch.

7. The method for predicting the remaining life of a low-voltage switch according to claim 6, characterized in that: The host computer module calculates the contact resistance according to the received voltage and current data, including: Read the contact voltage data during the closing process of the low-voltage switch and calculate the average value of the contact voltage during the closing process; Read the contact current data during the closing process of the low-voltage switch and calculate the average value of the contact current during the closing process; Calculate the contact resistance using the following formula: R j =(U*a) / (I*b); Among them, U is the average value of the contact voltage during the closing process, I is the average value of the contact current during the closing process, and a and b are acquisition proportional coefficients.

8. The method for predicting the remaining life of a low-voltage switch according to claim 6, characterized in that: The method of performing hypothesis testing on the characteristic parameters of the contact resistance according to the typical probability distribution to determine the probability distribution function type of the contact resistance of the low-voltage switch under test includes: According to the typical probability distribution, the KS test method is used to determine the probability distribution function type of the first 1000 contact resistances of the tested low-voltage switch; A KS test is performed based on the calculated contact resistance value. Under the condition of a significance level of 0.05, it is determined which probability distribution the contact resistance obeys. The probability distribution includes normal distribution, extreme value distribution, exponential distribution, Γ distribution, lognormal distribution, Poisson distribution, Rayleigh distribution, Weibull distribution and β distribution.

9. The method for predicting the remaining life of a low-voltage switch according to any one of claims 6 to 8, characterized in that: According to the determined probability distribution function type, a model of the relationship between the mean and variance of the contact resistance and the electrical life is established, and a univariate linear regression method is used to perform regression analysis on the data, and the sum of square errors of each function is calculated. The function relationship with the smallest sum of square errors is used as the optimal relationship model between the mean, variance and electrical life, thereby realizing the prediction of the remaining electrical life of the low-voltage switch as follows: According to the determined probability distribution type, the mean and variance of the first 1000 contact resistances are respectively related to the electrical life, including the monotonic function relationship of linear function, exponential function, logarithmic function, and power function. The SSE of each function is calculated to determine the optimal relationship model, thereby realizing the remaining electrical life prediction of the low-voltage switch.

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