Variable-frequency power supply control system

Abstract

The invention specifically relates to a variable-frequency power supply control system, and relates to the technical field of variable-frequency power supplies. An analysis module; and the adjusting module is controlled. According to the invention, the mains supply monitoring module accurately collects voltage, current and frequency parameter information of the mains supply according to a set time interval in a preset monitoring time zone, and the analysis module uses a scientific analysis method to respectively obtain a voltage abnormal value, a current abnormal value and an unbalance frequency ratio and comprehensively processes the values into evaluation coefficients. Compared with a traditional monitoring system, the comprehensive and accurate parameter analysis mode can more accurately reflect the actual operation state of the commercial power, can timely and accurately discover tiny anomalies in the operation of the commercial power, gives an early warning in advance, and provides a reliable basis for guaranteeing the stable operation of electric equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of variable-frequency power supplies, and particularly to a variable-frequency power supply control system. Background Art

[0002] In modern industrial production and daily life, the stability of the commercial power supply is crucial for the normal operation of various electrical equipment. However, the commercial power grid is often affected by various factors, such as grid load changes, power equipment failures, natural environment interference, etc., resulting in fluctuations and abnormalities in the voltage, current, and frequency of the commercial power supply. These abnormal conditions may cause damage to the equipment relying on the commercial power supply, affect production efficiency, and even lead to safety accidents.

[0003] Existing variable-frequency power supply control systems have certain limitations in monitoring commercial power parameters and dealing with abnormal situations. For example, the analysis of commercial power parameters is not comprehensive and accurate enough to accurately evaluate the degree of abnormality of the commercial power supply; in the face of different degrees of abnormalities, there are no targeted treatment measures and it is impossible to ensure the stable operation of the equipment in a timely and effective manner.

[0004] Therefore, a variable-frequency power supply control system that can comprehensively and accurately monitor commercial power parameters and reasonably handle abnormal situations is needed to address the above-mentioned problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a variable-frequency power supply control system to solve the above problems.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions: A variable-frequency power supply control system includes the following parts: Mains monitoring module: preset a monitoring time zone, and collect the voltage, current, and frequency parameter information of the commercial power supply at a set time interval within this time zone; Analysis module: analyze the obtained parameter information of each item to obtain voltage anomaly value, current anomaly value, and unbalance frequency ratio respectively, and comprehensively process the obtained three values to obtain an evaluation coefficient; Control and adjustment module: preset the value ranges of three groups of thresholds, and each group of threshold value ranges corresponds to a status level. Match the evaluation coefficient with the value ranges of the three groups of thresholds to obtain the status level corresponding to the evaluation coefficient, where the status levels are divided into normal, abnormal, and emergency; perform corresponding processing according to the status level corresponding to the evaluation coefficient.

[0007] Preferably, after analyzing the obtained voltage, current, and frequency parameter information of the commercial power supply to obtain the voltage anomaly value, the specific process includes the following parts: Obtain the actual output voltage value of the mains electricity in any monitored time zone, calculate the difference between it and the specified standard voltage value of the mains electricity, and then divide by the specified standard voltage value of the mains electricity to obtain the voltage deviation ratio; preset the voltage deviation ratio threshold, calculate the difference between the voltage deviation ratio and the voltage deviation ratio threshold to obtain the deviation degree, and sum up all the deviation degrees in the monitored time zone to obtain the total deviation degree; Sample the voltage value several times in the monitored time zone, calculate the average value, and then calculate the voltage fluctuation value through the voltage fluctuation value formula; Fuse the total deviation degree and the voltage fluctuation value to obtain the voltage anomaly value.

[0008] Preferably, after analyzing the obtained voltage, current, and frequency parameter information of the mains electricity, an abnormal current value is obtained. The specific process includes the following parts: Based on the sinusoidal alternating current characteristics of the mains electricity, establish a current function that changes with time in the monitored time zone, and substitute this function into the formula to calculate the effective current value; preset the effective current threshold, calculate the difference between the effective current value and the effective current threshold, and take the absolute value to obtain the effective deviation value; Convert the obtained current signal of the mains electricity into a digital signal, and perform Fourier transform on it to obtain the amplitudes of each harmonic current, and divide the amplitudes of each harmonic current by to obtain the effective values of each harmonic current; substitute the effective values of each harmonic current into the formula to calculate the harmonic distortion rate of the monitored time zone; preset the harmonic distortion rate threshold, calculate the difference between the harmonic distortion rate and the harmonic distortion rate to obtain the distortion difference; After presetting the weight factors of the effective deviation value and the distortion difference, multiply the effective deviation value and the distortion difference by their corresponding weight factors respectively and then sum them up to obtain the abnormal current value.

[0009] Preferably, after analyzing the obtained voltage, current, and frequency parameter information of the mains electricity, an unbalanced frequency ratio value is obtained. The specific process includes the following parts: According to the Nyquist sampling theorem, sample the current signal of the mains electricity in the monitored time zone to obtain a discrete current sampling sequence, and perform a transformation on the sampling sequence to obtain a frequency domain representation; Find the frequency domain index value corresponding to the frequency component with the largest amplitude in the frequency domain representation, and substitute this frequency domain index value into the formula to calculate the frequency; Calculate the difference between the obtained frequency and the rated frequency and take the absolute value to obtain the frequency deviation value; preset the allowable range of the frequency deviation value, and record the frequency deviation values that are not within the allowable range of the frequency deviation value as abnormal frequency deviation values; Collect the frequencies at several nodes of the municipal power grid, extract the abnormal frequency deviation values from the frequencies at each node, and divide the number of abnormal frequency deviation values by the number of nodes to obtain the imbalance frequency ratio value.

[0010] Preferably, the evaluation coefficient is obtained after comprehensively processing the obtained voltage abnormal value, current abnormal value, and imbalance frequency ratio value. The specific process includes: after normalizing the voltage abnormal value, current abnormal value, and imbalance frequency ratio value, taking the voltage abnormal value and current abnormal value as the two right-angled sides of a right-angled triangle respectively, connecting the remaining side length to form a complete right-angled triangle, and establishing a triangular pyramid model with the imbalance frequency ratio value as the height, and calculating the surface area of the triangular pyramid model and denoting it as the evaluation coefficient.

[0011] Preferably, the corresponding processing is carried out according to the state level corresponding to the evaluation coefficient. The specific process includes the following parts: If the state level corresponding to the evaluation coefficient is normal, then continue to maintain the current monitoring frequency and parameter collection, and regularly record the various parameter information of the municipal power and the evaluation coefficient, as well as the voltage abnormal value, current abnormal value, and imbalance frequency ratio value corresponding to the evaluation coefficient; If the state level corresponding to the evaluation coefficient is abnormal, then determine the degree of abnormality and carry out corresponding processing according to the degree of abnormality; If the state level corresponding to the evaluation coefficient is urgent, then immediately cut off the connection between the variable-frequency power supply and the municipal power, start the standby power supply for continuous power supply, mark the connection time of cutting off the variable-frequency power supply and the voltage abnormal value, current abnormal value, and imbalance frequency ratio value corresponding to the evaluation coefficient as fault information, and send the fault information to the intelligent terminal of the maintenance personnel together.

[0012] Preferably, when the state level corresponding to the evaluation coefficient is abnormal, then determine the degree of abnormality and carry out corresponding processing according to the degree of abnormality. Specifically, it includes the following parts: Determine the value range of the evaluation coefficient corresponding to the current abnormal value, extract the minimum evaluation coefficient from this value range, and denote this minimum evaluation coefficient as the abnormal reference value; calculate the difference between the evaluation coefficient and the abnormal reference value to obtain the level determination value; Preset the value ranges of three groups of thresholds, and each group of thresholds corresponds to an abnormal level. Match the level determination value with the preset value ranges of the three groups of thresholds to obtain the abnormal level corresponding to the level determination value; among them, the abnormal levels include mild abnormality, moderate abnormality, and severe abnormality; and trigger the corresponding-level sound and light alarm according to the abnormal level, where the sound and light alarm levels are divided into level one, level two, and level three.

[0013] Preferably, the alarm methods of the level-one sound and light alarm, level-two sound and light alarm, and level-three sound and light alarm are respectively: Level 1 acoustic-optical alarm, with blue lights flashing several times per second and beeping prompts emitted at a preset frequency and for a preset duration; Level 2 acoustic-optical alarm, with yellow lights flashing at several times the frequency of the Level 1 acoustic-optical alarm per second and beeping prompts emitted at several times the frequency and for several times the duration of the Level 1 acoustic-optical alarm; Level 3 acoustic-optical alarm, with red lights flashing at several times the frequency of the Level 2 acoustic-optical alarm per second and beeping prompts emitted at several times the frequency and for several times the duration of the Level 2 acoustic-optical alarm.

[0014] Preferably, the screening process of the preferred maintenance personnel specifically includes the following parts: After obtaining the location of the faulty variable-frequency power supply, draw a circle on the map with the location of the faulty variable-frequency power supply as the center and a preset size as the radius, obtain all maintenance personnel within this circular range, and screen out the maintenance personnel within the normal working hours; Obtain the working years of each screened maintenance personnel, preset the minimum required working years, compare the working years of each maintenance personnel with the minimum required working years, remove the maintenance personnel with working years lower than the minimum required working years, analyze the remaining maintenance personnel to obtain the processing values of each maintenance personnel in turn, arrange the processing values of each maintenance personnel in descending order from left to right according to size, and take the maintenance personnel corresponding to the maximum processing value as the preferred maintenance personnel.

[0015] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are: 1. Through the mains monitoring module, the present invention accurately collects the voltage, current, and frequency parameter information of the mains at set time intervals within a preset monitoring time zone. The analysis module uses scientific analysis methods to respectively obtain the voltage anomaly value, current anomaly value, and unbalanced frequency ratio value, and comprehensively processes these values into an evaluation coefficient. This comprehensive and accurate parameter analysis method can more accurately reflect the actual operating state of the mains compared with traditional monitoring systems, and can also timely and accurately detect subtle anomalies in the mains operation, providing an early warning and a reliable basis for ensuring the stable operation of electrical equipment.

[0016] 2. By presetting three groups of threshold ranges through the control and adjustment module, corresponding to the three state levels of normal, abnormal, and emergency, after matching the evaluation coefficient with them, corresponding processing measures are taken according to different state levels. This intelligent hierarchical response mechanism enables the system to make the most appropriate response when facing different degrees of anomalies in the mains; screening maintenance personnel with the fault location as the center and determining the preferred personnel in combination with factors such as working years greatly improves the fault handling efficiency. Description of the Drawings

[0017] In the following description of exemplary embodiments in conjunction with the accompanying drawings, more details, features, and advantages of the present application are disclosed, in which: Figure 1 is a flowchart of the present invention; Detailed implementation manners

[0018] Several embodiments of the present application will be described in more detail below with reference to the accompanying drawings so that those skilled in the art can implement the present application. The present application can be embodied in many different forms and for many different purposes and should not be limited to the embodiments set forth herein. These embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the application to those skilled in the art. The embodiments do not limit the present application.

[0019] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning that is consistent with their meaning in the relevant art and / or the context of this specification, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0020] Please refer to Figure 1 as shown, the present invention provides a technical solution: A variable-frequency power supply control system includes the following parts: Mains monitoring module: preset a monitoring time zone, and collect voltage, current, and frequency parameter information of the mains within this time zone at a set time interval; Analysis module: analyze the obtained voltage, current, and frequency parameter information of the mains to obtain voltage anomaly values, current anomaly values, and unbalance frequency ratios respectively, and comprehensively process the three obtained values to obtain an evaluation coefficient; After analyzing the obtained voltage, current, and frequency parameter information of the mains, voltage anomaly values are obtained. The specific process includes the following parts: Obtain the actual output voltage value of the mains in any monitoring time zone, calculate the difference between it and the specified standard voltage value of the mains, and then divide by the specified standard voltage value of the mains to obtain the voltage deviation ratio; preset a voltage deviation ratio threshold, calculate the difference between the voltage deviation ratio and the voltage deviation ratio threshold to obtain the deviation degree, and sum up all the deviation degrees in the monitoring time zone to obtain the total deviation degree; Sample the voltage value several times within the monitoring time zone, calculate the average value, and then calculate the voltage fluctuation value through a formula; Calculate the voltage fluctuation value through the voltage fluctuation value formula. The specific process includes: , to obtain the voltage fluctuation value , where is the total number of voltage samplings, is the voltage value obtained from the i-th sampling, , is the average value of the voltage, which is the value obtained by performing an arithmetic mean on all sampled voltage values ; After fusing the total deviation degree and the voltage fluctuation value, an abnormal voltage value is obtained; The specific process includes the following parts: Mark the deviation degree as , and and are substituted into the formula to calculate the abnormal voltage value, where are the weight factors corresponding to the deviation degree and the fluctuation value respectively, is the maximum allowable voltage fluctuation value; After analyzing the voltage, current, and frequency parameter information of the obtained commercial power, an abnormal current value is obtained. The specific process includes the following parts: Based on the sinusoidal alternating current characteristics of the commercial power, a current function that changes with time is established in the monitoring time zone, and this function is substituted into the formula to calculate the effective current value; a preset effective current threshold is set, and the absolute value is taken after calculating the difference between the effective current value and the effective current threshold to obtain the effective deviation value; The specific calculation process includes: The formula for the current function that changes with time is , where is the maximum value of the current, is the angular frequency, is the initial phase; Substitute this current function into the formula: to obtain the effective current value, where is the period of the alternating current, which is 0.02 seconds; Convert the obtained current signal of the commercial power into a digital signal and perform a Fourier transform on it to obtain the amplitudes of the harmonic currents of each order, and divide the amplitudes of the harmonic currents of each order by to obtain the effective values of the harmonic currents of each order; substitute the effective values of the harmonic currents of each order into the formula to calculate the harmonic distortion rate of the monitoring time zone; a preset harmonic distortion rate threshold is set, and the difference is calculated between the harmonic distortion rate and the harmonic distortion rate to obtain the distortion difference; The specific calculation process includes: Substitute the effective values of the harmonic currents of each order into the formula: to obtain the harmonic distortion rate, where is the effective value of the n-th harmonic current, is the effective value of the fundamental current. Since the commercial power frequency is , so the frequency of the fundamental wave current is ; After presetting the weight factors of the preset effective deviation value and the distortion difference value, the effective deviation value and the distortion difference value are respectively multiplied by their corresponding weight factors and then summed to obtain the current anomaly value; After analyzing the voltage, current, and frequency parameter information of the obtained mains power, the unbalance frequency ratio is obtained. The specific process includes the following parts: According to the Nyquist sampling theorem, after sampling the current signal of the mains power in the monitoring time zone, a discrete current sampling sequence is obtained, and the sampling sequence is transformed to obtain the frequency domain representation; Find the frequency domain index value corresponding to the frequency component with the largest amplitude in the frequency domain representation, and substitute the frequency domain index value into the formula to calculate the frequency; Calculate the difference between the obtained frequency and the rated frequency and take the absolute value to obtain the frequency deviation value; preset the allowable range of the frequency deviation value, and record the frequency deviation value that is not within the allowable range of the frequency deviation value as the abnormal frequency deviation value; Collect the frequencies at several nodes of the power grid, extract the abnormal frequency deviation values from the frequencies at each node, and divide the number of abnormal frequency deviation values by the number of nodes to obtain the unbalance frequency ratio; The specific calculation process includes: after sampling, a discrete current sampling sequence is obtained , where , is the number of sampling points; Perform transformation on the sampling sequence according to the formula: to obtain the frequency domain representation , where , and extract the value corresponding to the frequency component with the largest amplitude, and substitute the value into the formula to calculate the frequency , where is the sampling frequency, is the number of sampling points; After comprehensively processing the obtained voltage anomaly value, current anomaly value, and unbalance frequency ratio to obtain the evaluation coefficient, the specific process includes: after normalizing the voltage anomaly value, current anomaly value, and unbalance frequency ratio, use the voltage anomaly value and current anomaly value as the two right-angled sides of a right-angled triangle respectively, connect the remaining side length to form a complete right-angled triangle, and establish a triangular pyramid model with the unbalance frequency ratio as the height, and calculate the surface area of the triangular pyramid model and record it as the evaluation coefficient; Control and regulation module: Preset the value ranges of three groups of thresholds, and each group of threshold value ranges corresponds to a status level. Match the evaluation coefficient with the three groups of threshold value ranges to obtain the status level corresponding to the evaluation coefficient, where the status levels are normal, abnormal, and urgent; perform corresponding processing according to the status level corresponding to the evaluation coefficient; Perform corresponding processing according to the status level corresponding to the evaluation coefficient. The specific process includes the following parts: If the status level corresponding to the evaluation coefficient is normal, continue to maintain the current monitoring frequency and parameter collection, and regularly record the various parameter information of the mains power and the evaluation coefficient, as well as the voltage anomaly value, current anomaly value, and imbalance frequency ratio corresponding to the evaluation coefficient; If the status level corresponding to the evaluation coefficient is abnormal, determine the degree of abnormality and perform corresponding processing according to the degree of abnormality; If the status level corresponding to the evaluation coefficient is urgent, immediately cut off the connection between the variable-frequency power supply and the mains power, start the standby power supply for continuous power supply, mark the time of cutting off the connection between the variable-frequency power supply and the mains power, as well as the voltage anomaly value, current anomaly value, and imbalance frequency ratio corresponding to the evaluation coefficient as fault information, and send the fault information to the intelligent terminals of the preferred maintenance personnel obtained after screening. When the intelligent terminal of the preferred maintenance personnel receives the fault information, it continuously emits an information prompt sound and vibration according to the type of prompt sound, vibration intensity, and prompt duration preset by the maintenance personnel until the preferred maintenance personnel view the fault information received on the terminal and arrive at the faulty variable-frequency power supply for maintenance processing within the preset time after viewing the information; The screening process of the preferred maintenance personnel specifically includes the following parts: After obtaining the location of the faulty variable-frequency power supply, draw a circle on the map with the location of the faulty variable-frequency power supply as the center and a preset size as the radius, obtain all the maintenance personnel within this circular range, and screen out the maintenance personnel within the normal working time range; Obtain the working years of each screened maintenance personnel, preset the minimum required working years, compare the working years of each maintenance personnel with the minimum required working years, remove the maintenance personnel with working years lower than the minimum required working years, analyze the remaining maintenance personnel to obtain the processing values of each maintenance personnel in turn, arrange the processing values of each maintenance personnel in descending order from left to right, and take the maintenance personnel corresponding to the largest processing value as the preferred maintenance personnel; The process of obtaining the processing value includes: Obtain the number of accident handling times of maintenance personnel within a preset time range before the current time point, and the handling time of each accident; preset the allowable range of accident handling time, and compare the handling time of each accident of the maintenance personnel with the allowable range of accident handling time in turn, and record the accident handling time within the allowable range of accident handling time as efficient time; count the efficient time of each maintenance personnel in turn, and divide each efficient time by the number of accident handling times of each maintenance personnel to obtain the completion ratio of each maintenance personnel; Obtain the number of variable frequency power supplies that fail again within a preset time interval after each accident handling by each maintenance personnel, and divide the number of variable frequency power supplies that fail again by the number of accident handling times of each maintenance personnel in turn to obtain the repair ratio of each maintenance personnel; Preset the weight factors of the completion ratio and the repair ratio, and calculate the product of the completion ratio and the repair ratio of each maintenance personnel and the corresponding weight factors in turn and then sum them up to obtain the processing value of each maintenance personnel; If the status level corresponding to the evaluation coefficient is abnormal, determine the degree of abnormality and perform corresponding processing according to the degree of abnormality, which specifically includes the following parts: Determine the value range of the evaluation coefficient corresponding to the current abnormal value, extract the minimum evaluation coefficient from this value range, and record this minimum evaluation coefficient as the abnormal reference value; calculate the difference between the evaluation coefficient and the abnormal reference value to obtain the level determination value; Preset the value ranges of three groups of thresholds, and each group of thresholds corresponds to an abnormal level. Match the level determination value with the preset value ranges of the three groups of thresholds to obtain the abnormal level corresponding to the level determination value; where the abnormal levels include mild abnormality, moderate abnormality and severe abnormality; and trigger the sound and light alarm of the corresponding level according to the abnormal level, where the sound and light alarm levels are divided into level one, level two and level three; When the abnormal level corresponding to the level determination value of the evaluation coefficient is mild abnormality, increase the acquisition frequency of the mains voltage, current and frequency within the monitoring time zone to the original preset multiple, and send out a level one sound and light alarm at a preset time interval through the sound and light alarm device installed on the variable frequency power supply; When the abnormal level corresponding to the level determination value of the evaluation coefficient is moderate abnormality, on the basis of the mild abnormality level, preset the thresholds corresponding to the voltage abnormal value, current abnormal value and unbalanced frequency ratio value respectively, and compare the voltage abnormal value, current abnormal value and unbalanced frequency ratio value with their thresholds in turn to determine the abnormal parameters of the mains power, and adjust the output parameters of the variable frequency power supply to compensate and regulate the abnormal parameters of the mains power; record the time when the abnormal parameters appear, the evaluation coefficient, and the voltage abnormal value, current abnormal value and unbalanced frequency ratio value corresponding to the evaluation coefficient together and send them to the intelligent terminal of the relevant maintenance personnel, and upgrade the level one sound and light alarm to a level two sound and light alarm; When the abnormal level where the level determination value corresponding to the evaluation coefficient is located is a severe abnormality, on the basis of the moderate abnormality level, a three-level audible and visual alarm is immediately triggered, and the variable-frequency power supply compensates and adjusts the abnormal parameters of the commercial power with the maximum power. Also, the level determination value corresponding to the evaluation coefficient is obtained in real time. If the level determination value remains within the value range corresponding to the severe abnormality within the preset duration, the status level where the evaluation coefficient is located is immediately upgraded from the abnormal level to the emergency level, and it is processed according to the processing method of the emergency level; The alarm methods of the first-level audible and visual alarm, the second-level audible and visual alarm, and the third-level audible and visual alarm are respectively: For the first-level audible and visual alarm, the light is blue and flashes several times per second, and emits a beeping prompt sound at a preset frequency for a preset duration; For the second-level audible and visual alarm, the light is yellow and flashes at several times the number of times of the first-level audible and visual alarm per second, and emits a beeping prompt sound at several times the frequency of the first-level audible and visual alarm for several times the duration of the first-level audible and visual alarm; For the third-level audible and visual alarm, the light is red and flashes at several times the number of times of the second-level audible and visual alarm per second, and emits a beeping prompt sound at several times the frequency of the second-level audible and visual alarm for several times the duration of the second-level audible and visual alarm.

[0021] The above formulas are all obtained by collecting a large amount of data for software simulation and selecting a formula close to the true value. The influence weight factors and specific coefficient values in the formula are set by those skilled in the art according to the actual situation and can be adjusted and modified later.

[0022] The above description of the embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A variable frequency power supply control system, characterized in that: Includes the following sections: Mains power monitoring module: preset monitoring time zone, and collect the voltage, current and frequency parameter information of the mains power at set time intervals within the time zone; Analysis module: After analyzing the voltage, current and frequency parameter information of the mains, the voltage abnormality value, current abnormality value and unbalanced frequency ratio value are obtained respectively, and the evaluation coefficient is obtained after comprehensive processing of the three values; Control and adjustment module: preset three groups of threshold value ranges, and each group of threshold value ranges corresponds to a state level, match the evaluation coefficient with the three groups of threshold value ranges, and obtain the state level corresponding to the evaluation coefficient, where the state level is divided into normal, abnormal, and emergency; perform corresponding processing according to the state level corresponding to the evaluation coefficient.

2. A variable frequency power supply control system according to claim 1, characterized in that: After analyzing the obtained voltage, current and frequency parameter information of the mains, the voltage abnormality value is obtained. The specific process includes the following parts: Obtain the actual output voltage value of the mains in any monitoring time zone, and calculate the difference between it and the standard voltage value specified by the mains, and then divide it by the standard voltage value specified by the mains to obtain the voltage deviation ratio; preset the voltage deviation ratio threshold, and calculate the difference between the voltage deviation ratio and the voltage deviation ratio threshold to obtain the deviation degree, and sum up all the deviation degrees in the monitoring time zone to obtain the total deviation degree; The voltage value is sampled several times in the monitoring time zone, and the voltage fluctuation value is calculated by the voltage fluctuation formula after the average value is calculated; The voltage anomaly value is obtained by fusing the total deviation and the voltage fluctuation value.

3. A variable frequency power supply control system according to claim 1, characterized in that: After analyzing the voltage, current and frequency parameter information of the mains electricity, the abnormal current value is obtained. The specific process includes the following parts: Based on the sinusoidal alternating current characteristics of the mains, a current function that changes with time in the monitoring time zone is established, and the current effective value is calculated by substituting the function into the current effective value formula; The effective current threshold is preset, and the difference between the effective current value and the effective current threshold is calculated and then the absolute value is taken to obtain the effective deviation value; The obtained mains current signal is converted into a digital signal and subjected to Fourier transform to obtain the amplitude of each harmonic current and divide the amplitude of each harmonic current by Get the effective value of each harmonic current; Substitute the effective value of each harmonic current into the harmonic distortion rate formula to calculate the harmonic distortion rate of the monitoring time zone; A harmonic distortion rate threshold is preset, and a distortion difference is obtained by performing a difference calculation between the harmonic distortion rate and the harmonic distortion rate; After the weight factors of the effective deviation value and the distortion difference value are preset, the effective deviation value and the distortion difference value are respectively multiplied by the corresponding weight factors and then summed to obtain the current abnormal value.

4. A variable frequency power supply control system according to claim 1, characterized in that: After analyzing the obtained voltage, current and frequency parameter information of the mains, the unbalanced frequency ratio value is obtained. The specific process includes the following parts: According to the Nyquist sampling theorem, after sampling the current signal of the mains power in the monitoring time zone, a discrete current sampling sequence is obtained, and the sampling sequence is transformed to obtain a frequency domain representation; Find the frequency domain index value corresponding to the frequency component with the largest amplitude in the frequency domain representation, and substitute the frequency domain index value into the frequency formula to calculate the frequency; The difference between the obtained frequency and the rated frequency is calculated and the absolute value is taken to obtain the frequency deviation value; the allowable range of the frequency deviation value is preset, and the frequency deviation value that is not within the allowable range of the frequency deviation value is recorded as an abnormal frequency deviation value; The frequencies at several nodes of the municipal power grid are collected, and abnormal frequency deviation values ​​are extracted from the frequencies at each node. The number of abnormal frequency deviation values ​​is counted and divided by the number of nodes to obtain the unbalanced frequency ratio value.

5. A variable frequency power supply control system according to claim 1, characterized in that: The evaluation coefficient is obtained after comprehensive processing of the voltage anomaly value, the current anomaly value, and the unbalanced frequency ratio value. The specific process includes: after normalizing the voltage anomaly value, the current anomaly value, and the unbalanced frequency ratio value, the voltage anomaly value and the current anomaly value are used as two right-angled sides of a right triangle respectively, and the remaining side length is connected to form a complete right triangle, and a triangular pyramid model is established with the unbalanced frequency ratio value as the height, and the surface area of ​​the triangular pyramid model is calculated and recorded as the evaluation coefficient.

6. A variable frequency power supply control system according to claim 1, characterized in that: The corresponding processing is performed according to the state level corresponding to the evaluation coefficient, and the specific process includes the following parts: If the status level corresponding to the evaluation coefficient is normal, the current monitoring frequency and parameter collection are maintained, and the various parameter information and evaluation coefficients of the mains power are regularly recorded, as well as the voltage abnormal value, current abnormal value, and unbalanced frequency ratio value corresponding to the evaluation coefficient; If the status level corresponding to the evaluation coefficient is abnormal, the degree of abnormality is determined and corresponding processing is performed according to the degree of abnormality; If the status level corresponding to the evaluation coefficient is emergency, the connection between the variable frequency power supply and the mains is immediately cut off, and the backup power supply is started for continuous power supply. The time of cutting off the connection between the variable frequency power supply and the mains and the voltage abnormality value, current abnormality value, and unbalanced frequency ratio value corresponding to the evaluation coefficient are marked as fault information, and the fault information is sent together to the intelligent terminal of the preferred maintenance personnel obtained after screening.

7. A variable frequency power supply control system according to claim 6, characterized in that: If the state level corresponding to the evaluation coefficient is abnormal, the degree of the abnormality is determined, and corresponding processing is performed according to the degree of the abnormality, which specifically includes the following parts: Determine the value range of the evaluation coefficient corresponding to the abnormal current value, extract the minimum evaluation coefficient from the value range, and record the minimum evaluation coefficient as the abnormal reference value; The grade determination value is obtained by performing difference calculation between the evaluation coefficient and the abnormal reference value; Three groups of threshold value ranges are preset, and each group of thresholds corresponds to an abnormality level. The level determination value is matched with the preset three groups of threshold value ranges to obtain the abnormality level corresponding to the level determination value; The abnormality levels include mild abnormality, moderate abnormality and severe abnormality; and the corresponding level of sound and light alarm is triggered according to the abnormality level, among which the sound and light alarm levels are divided into level one, level two and level three.

8. A variable frequency power supply control system according to claim 7, characterized in that: The alarm modes of the first-level sound and light alarm, the second-level sound and light alarm, and the third-level sound and light alarm are respectively: Level 1 sound and light alarm, the light is blue, flashes several times per second, and emits a buzzing tone at a preset frequency and for a preset duration; Second level sound and light alarm, the light is yellow, flashing several times per second as the first level sound and light alarm, and beeping at several times the frequency and duration of the first level sound and light alarm; The third level sound and light alarm uses red light, flashes several times per second as that of the second level sound and light alarm, and emits a buzzer tone at a frequency and duration that is several times that of the second level sound and light alarm.

9. A variable frequency power supply control system according to claim 6, characterized in that: The screening process of the preferred maintenance personnel specifically includes the following parts: After obtaining the location of the faulty variable frequency power supply, a circle is drawn on the map with the location of the faulty variable frequency power supply as the center and a preset size as the radius, all maintenance personnel within the circle are obtained, and maintenance personnel who are within the normal working time range are screened out; Obtain the length of service of each screened maintenance personnel, and preset the minimum required length of service, compare the length of service of each maintenance personnel with the minimum required length of service, remove the maintenance personnel with a length of service lower than the minimum required length of service, analyze the remaining maintenance personnel, obtain the processing value of each maintenance personnel in turn, arrange the processing value of each maintenance personnel in descending order from left to right according to size, and select the maintenance personnel corresponding to the maximum processing value as the preferred maintenance personnel.

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