Adaptive frequency converter over-current protection method and system

Abstract

The invention discloses a self-adaptive frequency converter over-current protection method and system, and relates to the technical field of wind turbine generator monitoring, and the method comprises the steps: obtaining an initial over-current protection parameter of a frequency converter; collecting a monitoring data set including a current data set, a vibration data set and a monitoring temperature set; performing current state analysis on the current data set to obtain a current trend value; respectively carrying out fluctuation fitting on the vibration data set and the monitoring temperature set to obtain auxiliary fluctuation factors; judging whether the current trend value is within a first-level early warning bandwidth of an overload current threshold, if so, obtaining a first early warning instruction, and triggering an overcurrent protection action; and if not, when the current trend value is within a second-level early warning bandwidth of the overload current threshold value, judging whether the auxiliary fluctuation factor meets a preset threshold value or not, if so, obtaining a second early warning instruction, and triggering an overcurrent protection action according to the second early warning instruction. The technical effects of improving the threshold response flexibility and fast over-current protection response are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine monitoring, and particularly to an adaptive overcurrent protection method and system for a frequency converter. Background Art

[0002] With the rapid development of power electronics technology, frequency converters have been widely used in the fields of industrial automation, energy, transportation, etc. As the core component of a motor drive system, a frequency converter can achieve functions such as stepless speed regulation and energy conservation and consumption reduction of the motor.

[0003] During the actual operation process, the frequency converter may encounter various faults, and the overcurrent fault is one of the most common ones. The overcurrent fault not only causes equipment damage but also may affect production safety and efficiency. The existing overcurrent protection methods mainly rely on setting fixed protection thresholds, and when the current exceeds the threshold, the protection action is triggered. Although this method is simple and easy to implement, it also has technical problems such as difficult threshold setting and slow response speed. Summary of the Invention

[0004] The present invention provides an adaptive overcurrent protection method and system for a frequency converter to solve the technical problems of difficult threshold setting and slow response speed in the prior art, and achieve the technical effects of improving the flexibility of threshold response and quickly responding to overcurrent protection.

[0005] In a first aspect, the present invention provides an adaptive overcurrent protection method for a frequency converter, wherein the method includes: Interact with the initial overcurrent protection parameters of the frequency converter, wherein the initial overcurrent protection parameters include an overload current threshold and an overload delay window; Collect a set of monitoring data of the target frequency converter within a preset monitoring window, wherein the set of monitoring data includes a current data set, a vibration data set, and a monitoring temperature set; Perform current state analysis according to the magnitude of the current value in the current data set to obtain a current trend value; Perform fluctuation fitting on the vibration data set and the monitoring temperature set respectively to obtain an auxiliary fluctuation factor; Judge whether the current trend value is within the first-level warning bandwidth of the overload current threshold. If so, obtain a first warning instruction and trigger an overcurrent protection action according to the first warning instruction; If not, when the current trend value is within the second-level warning bandwidth of the overload current threshold, judge whether the auxiliary fluctuation factor meets a preset threshold. If so, obtain a second warning instruction and trigger an overcurrent protection action according to the second warning instruction.

[0006] In a second aspect, the present invention also provides an adaptive overcurrent protection system for a frequency converter, wherein the system includes: A protection parameter extraction module, which is used to interact with the initial overcurrent protection parameters of the frequency converter. Among them, the initial overcurrent protection parameters include an overload current threshold and an overload delay window; A monitoring and acquisition module, which is used to acquire a set of monitoring data of the target frequency converter within a preset monitoring window. Among them, the set of monitoring data includes a current data set, a vibration data set, and a monitored temperature set; A trend analysis module, which is used to analyze the current state according to the magnitude of the current value in the current data set to obtain a current trend value; A fluctuation fitting module, which is used to perform fluctuation fitting on the vibration data set and the monitored temperature set respectively to obtain an auxiliary fluctuation factor; A first-level warning module, which is used to judge whether the current trend value is within the first-level warning bandwidth of the overload current threshold. If so, obtain a first warning instruction and trigger an overcurrent protection action according to the first warning instruction; A second-level warning module, which is used to, if not, when the current trend value is within the second-level warning bandwidth of the overload current threshold, judge whether the auxiliary fluctuation factor meets a preset threshold. If so, obtain a second warning instruction and trigger an overcurrent protection action according to the second warning instruction.

[0007] The present invention discloses an adaptive overcurrent protection method and system for a frequency converter, including: interacting with the frequency converter to obtain initial overcurrent protection parameters including an overload current threshold and an overload delay window; collecting monitoring data of the frequency converter within a preset monitoring window, including current data, vibration data, and monitored temperature; analyzing the current state according to the current data to obtain a current trend value; performing fluctuation fitting on the vibration data and the monitored temperature to obtain an auxiliary fluctuation factor; judging whether the current trend value is within the first-level warning bandwidth of the overload current threshold. If so, trigger a first warning instruction; if not, and the current trend value is within the second-level warning bandwidth of the overload current threshold, then judge whether the auxiliary fluctuation factor meets a preset threshold, and in the case of meeting, trigger a second warning instruction. The adaptive overcurrent protection method and system disclosed by the present invention solve the technical problems of difficult threshold setting and slow response speed, and achieve the technical effects of improving the flexibility of threshold response and quickly responding to overcurrent protection. Description of the Drawings

[0008] Figure 1 It is a flowchart of an adaptive overcurrent protection method for a frequency converter according to the present invention; Figure 2 It is a structural diagram of an adaptive overcurrent protection system for a frequency converter according to the present invention.

[0009] Description of the accompanying drawing reference numerals: Protection parameter extraction module 11, monitoring and acquisition module 12, trend analysis module 13, fluctuation fitting module 14, primary warning module 15, secondary warning module 16. Specific implementation mode

[0010] In the embodiments of the present invention, the overall idea adopted to solve the technical problems of difficult threshold setting and slow response speed existing in the prior art is as follows: First, through an interactive frequency converter, obtain initial overcurrent protection parameters including an overcurrent threshold and an overload delay window; then, collect monitoring data of the target frequency converter within a preset monitoring window, and these data cover a current data set, a vibration data set, and a monitored temperature set. Then, use the current values in the current data set to perform current state analysis to obtain a current trend value; then, perform fluctuation fitting on the vibration data set and the monitored temperature set to obtain an auxiliary fluctuation factor. Furthermore, determine whether the current trend value is within the primary warning bandwidth of the overcurrent threshold. If so, obtain a first warning instruction and trigger an overcurrent protection action according to this first warning instruction. If the current trend value is not within the primary warning bandwidth but within the secondary warning bandwidth of the overcurrent threshold, determine whether the auxiliary fluctuation factor reaches a preset threshold. If it reaches, then obtain a second warning instruction and execute an overcurrent protection action according to this instruction.

[0011] The above technical solution will be described in detail below in combination with the accompanying drawings of the specification and specific implementation modes to better understand the above technical solution. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments of the present invention. It should be understood that the present invention is not limited to the example embodiments for explaining the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention. In addition, it should be noted that for the convenience of description, only parts related to the present invention are shown in the drawings, not all of them.

[0012] Embodiment 1 Figure 1 It is a flowchart of an adaptive overcurrent protection method for a frequency converter of the present invention; wherein, it includes: Interact with the initial overcurrent protection parameters of the frequency converter, where the initial overcurrent protection parameters include an overcurrent threshold and an overload delay window; Overcurrent protection is an important safety means for protecting the frequency converter and the frequency converter control equipment. Optionally, the overcurrent protection of the frequency converter is realized through the set overcurrent threshold and overload delay window. In other words, the initial overcurrent protection parameters of the frequency converter are the overcurrent threshold and the corresponding overload delay window.

[0013] Among them, the overcurrent threshold reflects the magnitude of the current for which current protection is required, and the overloading delay window refers to the duration for which the overcurrent for current protection lasts. That is to say, when the overcurrent magnitude of the target frequency converter is greater than the overcurrent threshold, a protection action is triggered. When the duration for which the overcurrent magnitude of the target frequency converter is greater than the overcurrent threshold is greater than the overloading delay window, the protection action is executed. Specifically, the protection action includes reducing the output frequency or stopping the output, etc.

[0014] Optionally, the initial overcurrent protection parameters include multiple sets of matched overcurrent thresholds and overloading delay windows. Among them, the matching of the overcurrent threshold and the overloading delay window is based on the thermal effect of the current on the frequency converter. A shorter overloading delay window corresponds to a higher overcurrent threshold, and a longer overloading delay window corresponds to a lower overcurrent threshold. Through such a setting, the frequency converter can cope with various overcurrent protection scenarios with different overcurrent degrees and overcurrent durations, improving the coverage of overcurrent protection.

[0015] Collect the monitoring data set of the target frequency converter within a preset monitoring window. Among them, the monitoring data set includes a current data set, a vibration data set, and a monitoring temperature set; Among them, the monitoring window is a specific time period during which the monitoring data of the frequency converter is collected and stored. The preset monitoring window is set with corresponding window parameters, including the time length of the monitoring window and the start or end time.

[0016] Optionally, during the monitoring window, the collected monitoring data set includes: a current data set, which refers to the set of magnitude values of the frequency converter current during the monitoring window; a vibration data set, which records the vibration data of the frequency converter and its drive motor during the monitoring window, including the amplitude, frequency, and phase of the vibration; a monitoring temperature set, which reflects the temperature performance of the frequency converter and its related components within the monitoring window.

[0017] Optionally, the monitoring data set is collected through various monitoring sensors set on the target frequency converter. Specifically, the monitoring sensors include a current sensor (such as a Hall effect sensor), a vibration sensor (such as a piezoelectric or accelerometer), and a temperature sensor (such as a thermocouple or infrared sensor).

[0018] Through the above methods and settings, the acquisition of the monitoring data of the frequency converter is realized to monitor the health status of the device and provide data support for subsequent overcurrent discrimination.

[0019] Perform current state analysis based on the magnitude of the current value in the current data set to obtain a current trend value; Optionally, the current values in the current dataset are multiple current magnitudes that vary and fluctuate. Therefore, through current state analysis, a representative current value is obtained and stored as the current trend value. That is to say, the current trend value is a typical value of multiple current values in the current dataset and can represent the current level of the current dataset.

[0020] Exemplarily, the current state analysis is carried out based on statistical and mathematical methods. First, the current data in the current dataset is cleaned to remove outliers and noise. Then, data smoothing techniques such as moving average, exponential smoothing, or low-pass filter are adopted to reduce the random fluctuations in the data and make the trend more obvious. Finally, for the smoothed current data, statistical analysis methods are used to extract characteristic values including mean, median, mode, or standard deviation, etc., and determine them as the trend values.

[0021] In some embodiments, current state analysis is performed according to the magnitude of the current values in the current dataset to obtain the current trend value. The method includes: Extract N current values from the current dataset, and use time as the horizontal coordinate axis and the current value as the vertical coordinate axis. Using the N current values as N coordinate points, construct a two-dimensional current distribution space. Take the straight line passing through the mean of the N current values and parallel to the horizontal coordinate axis as the first trend line. Use the first trend line to divide the two-dimensional current distribution space into an upper space and a lower space. Compare the number of coordinate points in the upper space and the lower space, and obtain the first trend direction according to the position of the space with more coordinate points relative to the first trend line, where the first trend direction includes an upward movement identifier and a downward movement identifier. Based on the first trend direction and the first trend line, perform current state analysis in the two-dimensional current distribution space to obtain the current trend value.

[0022] Optionally, the current dataset is the current values of multiple sampling points obtained based on a preset sampling rate. Among them, the number N of current values in the current dataset is determined based on the monitoring window length and the sampling rate, and N is the ratio of the monitoring window length to the sampling rate plus 1. The N current values in the current dataset have sampling time sequence marks.

[0023] Exemplarily, first, a parameter space is constructed based on a plane rectangular coordinate system, where the horizontal axis is the sampling time and the vertical axis is the magnitude of the current value, forming a two-dimensional space of current distribution. Then, the mean value a of the above N current values is calculated, and the first trend line is expressed as y = a. Further, based on the first trend line, the two-dimensional space of current distribution is divided into an upper space and a lower space. The upper space refers to the area where all the coordinate points with current values greater than the first trend line are located, expressed as y > a, and the lower space refers to the area where all the coordinate points with current values less than the first trend line are located, expressed as y < a.

[0024] Optionally, compare the number of coordinate points in the upper space and the lower space. If the number of coordinate points in the upper space is more than that in the lower space, the first trend direction is characterized as an upward movement identifier; if the number of coordinate points in the lower space is more than that in the upper space, the first trend direction is characterized as a downward movement identifier.

[0025] In some implementation manners, based on the first trend direction and the first trend line, current state analysis is performed in the two-dimensional space of current distribution to obtain the current trend value. The method includes: Based on the first trend direction, move the first trend line according to a preset moving step length to obtain a first moving line; Based on the first trend direction, move the first moving line according to the preset moving step length to obtain a second moving line; Calculate the first current trend degree of the first moving line and the second current trend degree of the second moving line respectively; Judge whether the first current trend degree is less than or equal to the second current trend degree. If so, based on the first trend direction, move the second moving line according to the preset moving step length to obtain a third moving line; After multiple movements, when the Nth current trend degree is greater than the (N - 1)th current trend degree, use the (N - 1)th moving line corresponding to the (N - 1)th current trend degree as the target moving line; Use the coordinate value of the intersection point of the target moving line and the vertical axis of the two-dimensional space of current distribution as the current trend value.

[0026] Optionally, the preset moving step is determined based on the range of N current values in the current dataset. Exemplarily, first, calculate the difference between the maximum and minimum values among the N current values to obtain the range; then, set the preset moving step based on the constrained step division coefficient and the response correction coefficient. The step division coefficient refers to the proportion of the step in the range. Preferably, the step division coefficient is set to 0.05; the response correction coefficient is determined based on the response performance preference of the target frequency converter and is selected by professional technicians. If the target frequency converter requires a lower response delay, the response correction coefficient is greater than 1, corresponding to generating a longer moving step.

[0027] By presetting the moving step through the above method, it is ensured that the first trend line with a large deviation from the dense region of the voltage value corresponds to a large moving step, so as to move to the dense region faster.

[0028] Optionally, based on the preset moving step, move the first trend line continuously in the first trend direction twice to form a first moving line and a second moving line. The first moving line is the line formed after the first trend line moves in the first trend direction once, and the second moving line is the line formed after the first trend line moves in the first trend direction twice.

[0029] Among them, the first current trend degree and the second current trend degree are obtained by analyzing the density of the coordinate points in the space where the first moving line and the second moving line are located. Furthermore, by judging the magnitudes of the first current trend degree and the second current trend degree, the position superiority and inferiority of the first moving line and the second moving line can be identified.

[0030] Specifically, if the first current trend degree is less than or equal to the second current trend degree, along the first trend direction, move the second moving line according to the preset moving step to obtain a third moving line, and perform iterative optimization of the position superiority and inferiority of the moving line until the Nth current trend degree of the Nth moving line is greater than the (N - 1)th current trend degree of the Nth moving line, then set the (N - 1)th moving line as the target moving line; Furthermore, use the ordinate of the intersection point of the target moving line and the vertical coordinate axis of the two-dimensional current distribution space as the current trend value. This current trend value represents the value with the densest current value distribution in the two-dimensional current distribution space.

[0031] In some implementation manners, calculate the first current trend degree of the first moving line and the second current trend degree of the second moving line respectively. The method includes: Count the number of coordinate points in the two-dimensional current distribution space whose distance to the first moving line is the preset moving step to generate the first current trend degree; Count the number of coordinate points in the two-dimensional current distribution space whose distance to the second moving line is the preset moving step to generate the second current trend degree.

[0032] In other words, taking the preset moving step as the statistical space width and the first moving straight line as the midline of the statistical space, the neighborhood of the first moving straight line is obtained. Then, the number of coordinate points located in the neighborhood of the first moving straight line in the two-dimensional space of the current distribution is statistically analyzed as the first current tendency degree. The first current tendency degree reflects the number of coordinate points around the first moving straight line and indirectly reflects the coordinate point density at the position where the first moving straight line is located.

[0033] Optionally, based on the same method principle as generating the first current tendency degree above, the second current tendency degree is obtained. Similarly, the second current tendency degree reflects the number of coordinate points around the second moving straight line and indirectly reflects the coordinate point density at the position where the second moving straight line is located. It should be understood that for the sake of simplicity of the specification, no further elaboration is made here.

[0034] Perform fluctuation fitting on the vibration data set and the monitored temperature set respectively to obtain an auxiliary fluctuation factor; In some embodiments, performing fluctuation fitting on the vibration data set and the monitored temperature set respectively to obtain an auxiliary fluctuation factor, the method includes: Calculate multiple vibration gradients corresponding to multiple vibration data in the vibration data set according to time sequence, where the multiple vibration gradients have multiple vibration gradient direction identifiers, and the vibration gradient direction identifiers include positive identifiers and negative identifiers; Calculate multiple temperature gradients corresponding to multiple temperature data in the monitored temperature set according to time sequence, where the multiple temperature gradients have multiple temperature gradient direction identifiers, and the temperature gradient direction identifiers include positive identifiers and negative identifiers; Construct an auxiliary fluctuation scatter plot according to the multiple vibration gradients, the multiple temperature gradients, the multiple vibration gradient direction identifiers, and the multiple temperature gradient identifiers; Perform fluctuation fitting based on the auxiliary fluctuation scatter plot to obtain the auxiliary fluctuation factor.

[0035] Optionally, calculate multiple vibration gradients corresponding to multiple vibration data in the vibration data set according to time sequence. Among them, the vibration gradient is obtained by calculating the change rate of the vibration data, and each vibration gradient has a direction identifier, including a positive identifier indicating that the vibration data is increasing and a negative identifier indicating that the vibration data is decreasing.

[0036] Optionally, based on the same method principle as calculating the multiple vibration gradients corresponding to multiple vibration data in the vibration data set above, obtain the multiple temperature gradients corresponding to multiple temperature data in the monitored temperature set. And the multiple temperature gradients have the same direction identifiers to reflect the direction of temperature change.

[0037] In some implementation manners, the method includes: Construct the framework of the auxiliary fluctuation scatter plot with time as the abscissa and gradient as the ordinate; Add the multiple vibration gradients into the auxiliary fluctuation scatter plot according to the multiple vibration gradient direction identifiers to obtain multiple vibration gradient scatter points; Add the multiple temperature gradients into the auxiliary fluctuation scatter plot according to the multiple temperature gradient direction identifiers to obtain multiple temperature gradient scatter points; Perform comprehensive fitting on the multiple vibration gradient scatter points and the multiple temperature gradient scatter points to obtain the auxiliary fluctuation factor.

[0038] Optionally, construct an auxiliary fluctuation scatter plot according to multiple vibration gradients, multiple temperature gradients, multiple vibration gradient direction identifiers, and multiple temperature gradient identifiers; First, establish a scatter plot coordinate system with time as the abscissa and gradient as the ordinate to form the framework of the auxiliary fluctuation scatter plot; Then, based on the multiple vibration gradient direction identifiers, perform scatter mapping of the multiple vibration gradients. Specifically, map the vibration gradients with positive vibration gradient direction identifiers above the horizontal axis and map the vibration gradients with negative vibration gradient direction identifiers below the horizontal axis.

[0039] Optionally, based on the same principle of the acquisition method of multiple vibration gradient scatter points, obtain multiple temperature gradient scatter points. It should be understood that for the sake of simplicity of the specification, no further elaboration will be made here.

[0040] Further, in some implementation manners, perform comprehensive fitting on the multiple vibration gradient scatter points and the multiple temperature gradient scatter points to obtain the auxiliary fluctuation factor. The method includes: Use the linear regression method to perform linear fitting on the multiple vibration gradient scatter points and the multiple temperature gradient scatter points to obtain a comprehensive fitting line; Take the slope of the comprehensive fitting line as the auxiliary fluctuation factor.

[0041] Among them, linear regression is a commonly used statistical method for studying the relationship between two or more variables. By performing linear fitting on the vibration gradient scatter points and temperature gradient scatter points through the linear regression method, the obtained comprehensive fitting line reflects the development trend of the vibration characteristics and temperature characteristics of the target frequency converter over time.

[0042] Further, the larger the slope of the obtained comprehensive fitting line, the faster the development of the vibration characteristics and temperature characteristics of the target frequency converter over time, and the positive or negative of the slope of the comprehensive fitting line can reflect the change direction of vibration and temperature. Therefore, take the slope of the comprehensive fitting line as the auxiliary fluctuation factor. This auxiliary fluctuation factor is used to assist in judging overcurrent of the target frequency converter.

[0043] Determine whether the current trend value is within the first-level warning bandwidth of the overload current threshold. If so, obtain a first warning instruction and trigger an overcurrent protection action according to the first warning instruction; Optionally, the overload current threshold is a current threshold set based on the dual-threshold method, including an upper threshold and a lower threshold. Exemplarily, the lower threshold is the rated current of the target frequency converter, and the upper threshold is the maximum current of the target frequency converter.

[0044] Optionally, configure the space above the above upper threshold as the first-level warning bandwidth. If the current trend value is within the first-level warning bandwidth, it indicates that the real-time current magnitude of the target frequency converter has exceeded the maximum current magnitude of the target frequency converter, and a first warning instruction is generated for current protection.

[0045] Optionally, the first warning instruction is used to invoke a higher-level current protection measure. Exemplarily, it includes: automatically reducing the working current, disconnecting the power supply, and sending an alarm to the operator for corresponding manual operations.

[0046] If not, when the current trend value is within the second-level warning bandwidth of the overload current threshold, determine whether the auxiliary fluctuation factor meets the preset threshold. If so, obtain a second warning instruction and trigger an overcurrent protection action according to the second warning instruction.

[0047] Optionally, configure the space between the above upper threshold and lower threshold as the second-level warning bandwidth. If the current trend value is within the second-level warning bandwidth, it indicates that the real-time current of the target frequency converter has exceeded the rated current of the target frequency converter but is still lower than the maximum current of the target frequency converter, and further discrimination is required.

[0048] Furthermore, determine whether the auxiliary fluctuation factor meets the preset threshold to assist in judging the state of the target frequency converter. The auxiliary fluctuation factor reflects the change speed and direction of the vibration and temperature of the target frequency converter. If the auxiliary fluctuation factor meets the preset threshold, it indicates that the deterioration trend of the vibration and temperature of the target frequency converter is relatively fast, and a second warning instruction is generated to initiate an overcurrent protection action.

[0049] By monitoring the trend value of the current and the auxiliary fluctuation factor, the state of the target frequency converter can be judged more accurately, thereby preventing possible overcurrent states in advance. At the same time, by setting different levels of warning bandwidths and thresholds, different protection measures can be taken according to the specific conditions of the target frequency converter and the surrounding environment, improving the adaptability and flexibility of overcurrent protection.

[0050] In summary, the adaptive overcurrent protection method for a frequency converter provided by the present invention has the following technical effects: By interacting with the frequency converter, obtain the initial overcurrent protection parameters including the overload current threshold and the overload delay window; collect the monitoring data of the frequency converter within a preset monitoring window, including current data, vibration data, and monitoring temperature; analyze the current status based on the current data to obtain the current trend value; perform fluctuation fitting on the vibration data and the monitoring temperature to obtain the auxiliary fluctuation factor; determine whether the current trend value is within the first-level warning bandwidth of the overload current threshold. If so, trigger the first-level warning instruction; if not, and the current trend value is within the second-level warning bandwidth of the overload current threshold, then determine whether the auxiliary fluctuation factor meets the preset threshold, and for the satisfied situation, trigger the second-level warning instruction, achieving the technical effects of improving the flexibility of threshold response and rapid overcurrent protection response.

[0051] Embodiment 2 Figure 2 It is a schematic structural diagram of an adaptive overcurrent protection system for a frequency converter according to the present invention. For example, Figure 1 In the present invention, the flowchart of an adaptive overcurrent protection method for a frequency converter can be implemented by a structure as shown in Figure 2 shown.

[0052] Based on the same concept as the adaptive overcurrent protection method for a frequency converter in the above embodiment, the present invention also provides an adaptive overcurrent protection system for a frequency converter, including: A protection parameter extraction module 11, configured to interact with the initial overcurrent protection parameters of the frequency converter, where the initial overcurrent protection parameters include an overload current threshold and an overload delay window; A monitoring and acquisition module 12, configured to collect a set of monitoring data of the target frequency converter within a preset monitoring window, where the set of monitoring data includes a set of current data, a set of vibration data, and a set of monitoring temperatures; A trend analysis module 13, configured to analyze the current status based on the magnitude of the current value in the set of current data to obtain a current trend value; A fluctuation fitting module 14, configured to perform fluctuation fitting on the set of vibration data and the set of monitoring temperatures respectively to obtain an auxiliary fluctuation factor; A first-level warning module 15, configured to determine whether the current trend value is within the first-level warning bandwidth of the overload current threshold. If so, obtain a first warning instruction and trigger an overcurrent protection action according to the first warning instruction; A second-level warning module 16, configured to, if not, when the current trend value is within the second-level warning bandwidth of the overload current threshold, determine whether the auxiliary fluctuation factor meets a preset threshold. If so, obtain a second warning instruction and trigger an overcurrent protection action according to the second warning instruction.

[0053] Among them, the trend analysis module 13 includes: A current distribution unit, configured to extract N current values from the current dataset, and construct a two-dimensional current distribution space with time as the horizontal axis, current value as the vertical axis, and the N current values as N coordinate points. A mean line construction unit, configured to use the mean value of the N current values and a straight line parallel to the horizontal axis as the first trend line. A hierarchical division unit, configured to divide the two-dimensional current distribution space into an upper space and a lower space by using the first trend line. A trend discrimination unit, configured to compare the number of coordinate points in the upper space and the lower space, and obtain a first trend direction according to the position of the space with more coordinate points relative to the first trend line, where the first trend direction includes an upward shift identifier and a downward shift identifier. A trend value unit, configured to perform current state analysis within the two-dimensional current distribution space based on the first trend direction and the first trend line, and obtain the current trend value.

[0054] In some implementation manners, the trend value unit in the trend analysis module 13 includes: A first movement unit, configured to move the first trend line based on the first trend direction according to a preset movement step length to obtain a first movement line. A second movement unit, configured to move the first movement line based on the first trend direction according to the preset movement step length to obtain a second movement line. A trend degree calculation unit, configured to calculate a first current trend degree of the first movement line and a second current trend degree of the second movement line respectively. A trend degree comparison unit, configured to determine whether the first current trend degree is less than or equal to the second current trend degree. If so, move the second movement line based on the first trend direction according to the preset movement step length to obtain a third movement line. A target movement line unit, configured to, after multiple movements, when the Nth current trend degree is greater than the (N - 1)th current trend degree, use the (N - 1)th movement line corresponding to the (N - 1)th current trend degree as the target movement line. A trend value acquisition unit, configured to use the coordinate value of the intersection point of the target movement line and the vertical axis of the two-dimensional current distribution space as the current trend value.

[0055] In some implementation manners, the trend degree calculation unit in the trend value unit includes: A first trend degree unit, configured to count the number of coordinate points in the two-dimensional current distribution space whose distance to the first movement line is the preset movement step length, and generate a first current trend degree. A second trend degree unit, configured to count the number of coordinate points whose distance to the second moving straight line in the two-dimensional space of the current distribution is the preset moving step length, and generate a second current trend degree.

[0056] Among them, the fluctuation fitting module 14 includes: A vibration gradient calculation unit, configured to calculate multiple vibration gradients corresponding to multiple vibration data in the vibration data set according to time sequence, wherein the multiple vibration gradients have multiple vibration gradient direction identifiers, and the vibration gradient direction identifiers include a positive identifier and a negative identifier; A temperature gradient calculation unit, configured to calculate multiple temperature gradients corresponding to multiple temperature data in the monitored temperature set according to time sequence, wherein the multiple temperature gradients have multiple temperature gradient direction identifiers, and the temperature gradient direction identifiers include a positive identifier and a negative identifier; A scatter point mapping unit, configured to construct an auxiliary fluctuation scatter plot according to the multiple vibration gradients, the multiple temperature gradients, the multiple vibration gradient direction identifiers, and the multiple temperature gradient identifiers; A fluctuation fitting unit, configured to perform fluctuation fitting based on the auxiliary fluctuation scatter plot to obtain the auxiliary fluctuation factor.

[0057] In some implementation manners, the fluctuation fitting module 14 further includes: A framework construction unit, configured to construct a framework of the auxiliary fluctuation scatter plot with time as the abscissa and gradient as the ordinate; A vibration gradient scatter point mapping unit, configured to add the multiple vibration gradients into the auxiliary fluctuation scatter plot according to the multiple vibration gradient direction identifiers to obtain multiple vibration gradient scatter points; A temperature gradient scatter point mapping unit, configured to add the multiple temperature gradients into the auxiliary fluctuation scatter plot according to the multiple temperature gradient direction identifiers to obtain multiple temperature gradient scatter points; A comprehensive fitting unit, configured to perform comprehensive fitting on the multiple vibration gradient scatter points and the multiple temperature gradient scatter points to obtain the auxiliary fluctuation factor.

[0058] In some implementation manners, the comprehensive fitting unit in the scatter point mapping unit includes: A straight line fitting unit, configured to perform straight line fitting on the multiple vibration gradient scatter points and the multiple temperature gradient scatter points by using a linear regression method to obtain a comprehensive fitting straight line; A slope extraction unit, configured to use the slope of the comprehensive fitting straight line as the auxiliary fluctuation factor.

[0059] It should be understood that the embodiments mentioned in this specification focus on their differences from other embodiments. The specific embodiments in the first-mentioned embodiment 1 are equally applicable to the self-adaptive inverter overcurrent protection system described in embodiment 2. For the sake of brevity of the specification, no further elaboration will be made here.

[0060] It should be understood that the disclosed embodiments of the present invention and the above descriptions enable those skilled in the art to implement the present invention using the present invention. At the same time, the present invention is not limited to the part of the embodiments mentioned above. It should be understood that those of ordinary skill in the art can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention and should all be included within the protection scope of the present invention.

Claims

1. An adaptive inverter overcurrent protection method, characterized in that: The method comprises: Interacting initial overcurrent protection parameters of the inverter, wherein the initial overcurrent protection parameters include an overload current threshold and an overload delay window; Collecting a monitoring data set of the target inverter within a preset monitoring window, wherein the monitoring data set includes a current data set, a vibration data set, and a monitoring temperature set; Performing current state analysis according to the current value in the current data set to obtain a current trend value; Performing fluctuation fitting on the vibration data set and the monitored temperature set respectively to obtain auxiliary fluctuation factors; Determine whether the current trend value is within the first-level warning bandwidth of the overload current threshold, and if so, obtain a first warning instruction, and trigger an overcurrent protection action according to the first warning instruction; If not, when the current trend value is within the secondary warning bandwidth of the overload current threshold, it is determined whether the auxiliary fluctuation factor meets the preset threshold. If so, a second warning instruction is obtained, and the overcurrent protection action is triggered according to the second warning instruction.

2. The method according to claim 1, characterized in that Performing current state analysis according to the current value in the current data set to obtain a current trend value, the method comprising: Extracting N current values ​​from the current data set, and constructing a two-dimensional current distribution space with time as the horizontal axis, the current value as the vertical axis, and the N current values ​​as N coordinate points; A straight line passing through the average of the N current values ​​and parallel to the abscissa axis is used as a first trend straight line; Using the first trend line to divide the current distribution two-dimensional space into an upper space and a lower space; Comparing the number of coordinate points in the upper space and the lower space, and obtaining a first trend direction according to the position of the space with a larger number of coordinate points relative to the first trend line, wherein the first trend direction includes an upward movement mark and a downward movement mark; Based on the first trend direction and the first trend straight line, current state analysis is performed in the two-dimensional space of current distribution to obtain the current trend value.

3. The method according to claim 2, characterized in that Based on the first trend direction and the first trend straight line, current state analysis is performed in the two-dimensional space of current distribution to obtain the current trend value, and the method includes: Based on the first trend direction, the first trend straight line is moved according to a preset moving step length to obtain a first moving straight line; Based on the first trend direction, the first moving straight line is moved according to the preset moving step length to obtain a second moving straight line; respectively calculating a first current trend of the first moving straight line and a second current trend of the second moving straight line; Determine whether the first current trend is less than or equal to the second current trend, and if so, move the second moving straight line according to the preset moving step length based on the first trend direction to obtain a third moving straight line; After multiple movements, when the Nth current trend is greater than the N-1th current trend, the N-1th moving straight line corresponding to the N-1th current trend is used as the target moving straight line; The coordinate value of the intersection of the target moving straight line and the ordinate axis of the current distribution two-dimensional space is used as the current trend value.

4. The method according to claim 3, characterized in that Respectively calculating a first current trend of the first moving straight line and a second current trend of the second moving straight line, the method comprising: Counting the number of coordinate points in the current distribution two-dimensional space whose distance to the first moving straight line is the preset moving step length, and generating a first current trend degree; The number of coordinate points whose distance from the second moving straight line in the two-dimensional current distribution space is the preset moving step length is counted to generate a second current trend.

5. The method according to claim 1, characterized in that Performing fluctuation fitting on the vibration data set and the monitored temperature set respectively to obtain an auxiliary fluctuation factor, the method comprising: Calculating multiple vibration gradients corresponding to multiple vibration data in the vibration data set in time sequence, wherein the multiple vibration gradients have multiple vibration gradient direction identifiers, and the vibration gradient direction identifiers include positive identifiers and negative identifiers; Calculate multiple temperature gradients corresponding to multiple temperature data in the monitoring temperature set according to time sequence, wherein the multiple temperature gradients have multiple temperature gradient direction identifiers, and the temperature gradient direction identifiers include positive identifiers and negative identifiers; constructing an auxiliary fluctuation scatter plot according to the multiple vibration gradients and the multiple temperature gradients, and the multiple vibration gradient direction identifiers and the multiple temperature gradient identifiers; Fluctuation fitting is performed based on the auxiliary fluctuation scatter plot to obtain the auxiliary fluctuation factor.

6. The method according to claim 5, characterized in that The method comprises: The framework of the auxiliary fluctuation scatter plot is constructed with time as the horizontal coordinate and gradient as the vertical coordinate; Adding the multiple vibration gradients into the auxiliary fluctuation scatter plot according to the multiple vibration gradient direction identifiers to obtain multiple vibration gradient scatter points; Adding the multiple temperature gradients into the auxiliary fluctuation scatter plot according to the multiple temperature gradient direction identifiers to obtain multiple temperature gradient scatter points; The auxiliary fluctuation factor is obtained by performing comprehensive fitting on the multiple vibration gradient scatter points and the multiple temperature gradient scatter points.

7. The method according to claim 6, characterized in that Comprehensively fitting the multiple vibration gradient scatter points and the multiple temperature gradient scatter points to obtain the auxiliary fluctuation factor, the method comprising: Performing straight line fitting on the plurality of vibration gradient scatter points and the plurality of temperature gradient scatter points using a linear regression method to obtain a comprehensive fitting straight line; The slope of the comprehensive fitting straight line is used as the auxiliary fluctuation factor.

8. An adaptive inverter overcurrent protection system, characterized in that: The system comprises: A protection parameter extraction module, wherein the protection parameter extraction module is used to exchange initial overcurrent protection parameters of the inverter, wherein the initial overcurrent protection parameters include an overload current threshold and an overload delay window; A monitoring and acquisition module, wherein the monitoring and acquisition module is used to acquire a monitoring data set of the target inverter within a preset monitoring window, wherein the monitoring data set includes a current data set, a vibration data set, and a monitoring temperature set; A trend analysis module, the trend analysis module is used to perform current state analysis according to the current value in the current data set to obtain a current trend value; A fluctuation fitting module, the fluctuation fitting module is used to perform fluctuation fitting on the vibration data set and the monitored temperature set respectively to obtain an auxiliary fluctuation factor; A first-level warning module, the first-level warning module is used to determine whether the current trend value is within the first-level warning bandwidth of the overload current threshold, and if so, obtain a first warning instruction, and trigger an overcurrent protection action according to the first warning instruction; The second warning module is used to determine whether the auxiliary fluctuation factor meets a preset threshold when the current trend value is within the secondary warning bandwidth of the overload current threshold. If so, a second warning instruction is obtained to trigger the overcurrent protection action according to the second warning instruction.

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