Method and system for detecting residual life of electrolytic capacitor of frequency converter

Abstract

The invention relates to the technical field of frequency converters, in particular to a frequency converter electrolytic capacitor residual life detection method and system, and the method comprises the steps: collecting the working parameters of a to-be-detected frequency converter, and collecting the ambient temperature of a to-be-estimated capacitor in the to-be-detected frequency converter; estimating the capacitor center temperature of the to-be-estimated capacitor according to the working parameters of the frequency converter and the ambient temperature of the capacitor; and estimating the residual life of the to-be-estimated capacitor according to the working parameters of the frequency converter, the capacitor ambient temperature and the capacitor center. In order to solve the problem that accurate estimation of the service life of a capacitor in a real scene cannot be realized in the prior art, a part of sensors are additionally arranged for a frequency converter, and various parameters, including working parameters of the frequency converter, temperature of a capacitor area and the like, under the real scene are acquired; based on the parameters, the capacitor center temperature of the to-be-estimated capacitor is firstly estimated, and then the residual life of the to-be-estimated capacitor is further estimated, so that accurate estimation of the life of the capacitor is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of frequency converters, and in particular to a method and system for detecting the remaining life of an electrolytic capacitor of a frequency converter. Background Art

[0002] During the operation of the inverter, the power device emits heat, causing its own temperature to rise continuously, which directly affects the health of the electrolytic capacitor. Failure of the electrolytic capacitor will cause the power unit to overheat, causing the inverter to shut down and affecting normal operation on site. Temperature and operating current are important factors affecting the life of the capacitor. Therefore, during the operation of the inverter, it is necessary to estimate the life of the capacitor in advance and notify the customer to replace the power unit before the service life is reached.

[0003] In the prior art, there are technical solutions for estimating the life of capacitors. For example, Chinese patent CN202110100410.3 discloses a method and system for estimating the probability distribution of capacitor life, which belongs to the field of power electronics technology. The method includes: establishing a linear model of capacitor decay time and capacitance decay ratio; introducing a random error term in the linear model and determining the distribution of the random error term; based on the distribution of the random error term, obtaining the probability distribution of decay time corresponding to a certain capacitance decay ratio observation value; based on a given confidence level and the corresponding probability distribution of decay time, calculating the confidence interval of the individual and mean of the corresponding decay time estimate; given the capacitance decay ratio when the capacitor reaches the life limit, the probability distribution of capacitor life is estimated. Not only can a more accurate life estimate be obtained under small sample data, but also the probability distribution of life can be estimated, and the confidence interval of life estimate under different confidence levels can be calculated. The algorithm is simple and easy to understand, with small amount of calculation, easy to implement, and has industrial application value.

[0004] However, in the actual implementation process, the inventors found that the current traditional life prediction is based on the single-cell life calculation formula of the electrolytic capacitor, and is not based on the on-site working conditions of the inverter. When the inverter works under harsh conditions such as high temperature and overload, the actual life loss of the electrolytic capacitor will be faster than predicted, which will lead to premature failure and inverter overheating shutdown. Replacing the power unit at this time will affect on-site production and cause adverse effects. Summary of the invention

[0005] In view of the above problems existing in the prior art, a method for detecting the remaining life of an electrolytic capacitor of a frequency converter is now provided;

[0006] On the other hand, a detection system for implementing the method for detecting the remaining life of the electrolytic capacitor of the frequency converter is also provided.

[0007] The specific technical solutions are as follows:

[0008] A method for detecting the remaining life of an electrolytic capacitor of a frequency converter, comprising:

[0009] Step S1: collecting operating parameters of the frequency converter to be detected, and collecting the ambient temperature of the capacitor to be estimated in the frequency converter to be detected;

[0010] The inverter operating parameters include real-time output frequency, ambient temperature inside the inverter, and real-time output current;

[0011] Step S2: estimating the capacitor center temperature of the capacitor to be estimated according to the inverter operating parameters and the ambient temperature of the capacitor;

[0012] Step S3: estimating the remaining life of the capacitor to be estimated according to the inverter operating parameters, the ambient temperature of the capacitor and the center of the capacitor.

[0013] On the other hand, in step S2, the method for estimating the center temperature of the capacitor includes:

[0014]

[0015] Where, T c is the center temperature of the capacitor;

[0016] con2 is the capacitor center temperature of the inverter to be tested calibrated at the rated frequency and rated output current;

[0017] I out is the real-time output current;

[0018] I outrating is the rated output current;

[0019] f out is the real-time output frequency;

[0020] f outrating is the rated output frequency.

[0021] On the other hand, the step S1 comprises:

[0022] Step S11: collecting the real-time output current from the current sensor, collecting the ambient temperature inside the inverter from the first temperature sensor, collecting the ambient temperature of the capacitor from the second temperature sensor, and reading the real-time output frequency of the inverter to be detected from the controller;

[0023] Step S12: extracting the rated output current and the rated output frequency from the memory.

[0024] On the other hand, in step S3, the estimation result of the remaining life of the capacitor to be estimated includes:

[0025] At least one of an estimated time period life of the capacitor to be estimated in a certain time period in the future, an estimated remaining life of the capacitor to be estimated after a plurality of time periods, and a percentage of the estimated remaining life.

[0026] On the other hand, the method for generating the estimated time period life includes:

[0027]

[0028] Where, L n is the estimated time period life at the nth time period;

[0029] L0 is the basic life of the capacitor to be evaluated;

[0030] con1 is the basic ambient temperature of the capacitor to be evaluated when calibrating the basic life;

[0031] T a is the ambient temperature inside the frequency converter;

[0032] T ac is the ambient temperature of the capacitor;

[0033] T c is the center temperature of the capacitor.

[0034] On the other hand, the method for generating the estimated remaining life includes:

[0035]

[0036] Where, L s The estimated remaining lifespan is:

[0037] L0 is the basic life span;

[0038] L n For time period t n The estimated time period of life is described above.

[0039] On the other hand, the method for generating the percentage of estimated remaining life includes:

[0040]

[0041] Wherein, L% is the percentage of the estimated remaining life;

[0042] L s The estimated remaining lifespan is:

[0043] L0 is the basic life span.

[0044] A detection system for implementing the above-mentioned method for detecting the remaining life of an electrolytic capacitor of a frequency converter;

[0045] The detection system comprises:

[0046] A first temperature sensor, wherein the first temperature sensor is arranged at an air inlet of the frequency converter to be detected;

[0047] The first temperature sensor collects the ambient temperature inside the inverter;

[0048] The inverter to be tested includes a plurality of capacitors to be evaluated and a control board;

[0049] a second temperature sensor, the second temperature sensor being arranged at a central position between the plurality of capacitors to be evaluated;

[0050] The second temperature sensor collects the ambient temperature of the capacitor;

[0051] A current sensor, the current sensor being arranged at the output end of the inverter to be detected; the current sensor collecting real-time output current;

[0052] a processing device, the processing device being respectively connected to the first temperature sensor, the second temperature sensor, the current sensor and the control board;

[0053] The processing device obtains the rated output current, rated output frequency and real-time output frequency of the inverter to be detected according to the control board;

[0054] The processing device estimates the remaining life of the capacitor to be estimated based on the ambient temperature inside the inverter, the ambient temperature of the capacitor, the real-time output current, the rated output current, the rated output frequency and the real-time output frequency.

[0055] On the other hand, the detection system further comprises a display screen, wherein the display screen is connected to the processing device;

[0056] The display screen displays the remaining life.

[0057] The above technical solution has the following advantages or beneficial effects:

[0058] In order to solve the problem that the capacitor life estimation method in the prior art is relatively fixed and cannot achieve accurate estimation of the capacitor life in actual machine scenarios, in this solution, some additional sensors are set for the inverter, and various parameters under actual machine conditions are collected, including the operating parameters of the inverter and the temperature of the capacitor area. Based on these parameters, the center temperature of the capacitor to be estimated is first estimated, and then its remaining life is further estimated, thereby achieving accurate estimation of the capacitor life. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The embodiments of the present invention will be described more fully with reference to the attached drawings, which are provided for illustration and description only and are not intended to limit the scope of the present invention.

[0060] Figure 1 It is an overall schematic diagram of an embodiment of the present invention;

[0061] Figure 2 This is a schematic diagram of step S1 in an embodiment of the present invention;

[0062] Figure 3 Schematic diagram of a processing system in an embodiment of the present invention. DETAILED DESCRIPTION

[0063] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0064] Some of the blocks shown in the accompanying drawings are functional entities that do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0065] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0066] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0067] The present invention comprises:

[0068] A method for detecting the remaining life of an electrolytic capacitor of a frequency converter, such as Figure 1 As shown, including:

[0069] Step S1: collecting the working parameters of the frequency converter to be detected, and collecting the ambient temperature of the capacitor to be estimated in the frequency converter to be detected;

[0070] The inverter operating parameters include real-time output frequency, ambient temperature inside the inverter, and real-time output current;

[0071] Step S2: estimating the center temperature of the capacitor to be estimated according to the operating parameters of the inverter and the ambient temperature of the capacitor;

[0072] Step S3: Estimate the remaining life of the capacitor to be estimated based on the inverter operating parameters, the temperature around the capacitor and the center of the capacitor.

[0073] Specifically, in order to address the problem that the capacitor life estimation method in the prior art is relatively fixed and cannot achieve accurate estimation of the capacitor life in actual machine scenarios, in this solution, some additional sensors are set for the inverter, and various parameters under actual machine conditions are collected, including the operating parameters of the inverter and the temperature of the capacitor area. Based on these parameters, the capacitor center temperature of the capacitor to be estimated is first estimated, and then its remaining life is further estimated, thereby achieving accurate estimation of the capacitor life.

[0074] During the implementation process, the above-mentioned remaining life detection method is mainly configured in the inverter equipment as an embodiment of a combination of software and hardware. For example, it includes a detection system consisting of a processing device, two temperature sensors, and a current sensor, wherein the processing device is configured with a specific computer program that can read the data in the sensor and execute the above-mentioned specific method flow.

[0075] Generally speaking, there are two temperature sensors, one is set at the air inlet of the inverter to be tested, used to collect the ambient temperature inside the inverter; the other is set near the capacitor to be evaluated, used to collect the temperature around the capacitor. In one embodiment, on the circuit board of a certain type of inverter to be tested, multiple capacitors to be evaluated are arranged in a matrix, and the temperature sensor is set at the center point between four rectangularly arranged capacitors to be evaluated, which is used to accurately measure the ambient temperature when the capacitor is working and generating heat.

[0076] The current sensor is arranged at the output end of the frequency converter to be detected. In some embodiments, the ammeter of the frequency converter with output current detection function can be directly reused to read the signal through the relevant interface.

[0077] The real-time output frequency of the inverter to be detected is usually determined by the control board of the inverter to be detected according to the configuration, and the processing device can read the configuration information of the control board through the data interface to determine the real-time output frequency;

[0078] Correspondingly, the rated output current and rated output frequency of the inverter to be detected are usually fixed parameters, and the processing device can read the configuration information of the control board through the data interface to determine the rated output current and rated output frequency.

[0079] In some embodiments, the rated output current and the rated output frequency may also be directly written into the storage part of the processing device and directly read.

[0080] According to actual needs, the above device can be integrated into the frequency converter or combined with the device in the frequency converter. For example, the processing device can be integrated into a part of the control board with computer instruction execution function by adding a computer program.

[0081] In one embodiment, in step S2, the method for estimating the center temperature of the capacitor includes:

[0082]

[0083] Where, T c is the center temperature of the capacitor;

[0084] con2 is the capacitor center temperature of the inverter to be tested calibrated at the rated frequency and rated output current;

[0085] I out is the real-time output current;

[0086] I outrating is the rated output current;

[0087] f out It is the real-time output frequency;

[0088] f outrating is the rated output frequency.

[0089] Specifically, in order to achieve accurate estimation of the life of the capacitor, in this embodiment, for the inverter of the corresponding model to be tested, the center temperature of the capacitor is first calibrated at the rated frequency and the rated output current.

[0090] Specifically, the process includes disassembling the capacitor, adding a temperature probe to the capacitor, and then controlling the inverter to be tested to output according to the rated frequency and rated output current, and measuring the center temperature of the capacitor based on the probe.

[0091] After the temperature sequence is collected, the data is cleaned, including comparison with the real-time output frequency and current, removal of data that has not entered the steady state, and then filtering the steady-state data to remove the burr data. Finally, a group of data with a smaller variance is selected, and the average is taken after intercepting through a window, so as to obtain the capacitor center temperature calibrated at the rated frequency and rated output current of the inverter to be tested.

[0092] On this basis, since the current size and temperature, frequency and temperature are all linearly related, two sets of coefficients are generated according to the real-time output current and the rated output current, the real-time output frequency and the rated output frequency, respectively, to estimate the actual center temperature of the capacitor, thereby improving the accuracy of subsequent life estimation.

[0093] In one embodiment, Figure 2As shown, step S1 includes:

[0094] Step S11: collecting the real-time output current from the current sensor, collecting the ambient temperature inside the inverter from the first temperature sensor, collecting the ambient temperature of the capacitor from the second temperature sensor, and reading the real-time output frequency of the inverter to be detected from the controller;

[0095] Step S12: extracting the rated output current and the rated output frequency from the memory.

[0096] Specifically, in order to realize the collection of the above parameters, in this embodiment, the real-time output current is first collected through the current sensor. The current sensor is arranged at the output end of the inverter to be detected, and the two ends are respectively connected to the U phase and the V phase, so as to accurately collect the real-time output current.

[0097] At the same time, the ambient temperature inside the frequency converter is collected from the first temperature sensor, and the ambient temperature of the capacitor is collected from the second temperature sensor.

[0098] The first temperature sensor is arranged at the air inlet of the frequency converter to be detected, so as to avoid the influence of the working temperature of the frequency converter to be detected on the ambient temperature collection.

[0099] The second temperature sensor is arranged at the center point between the four rectangularly arranged capacitors to be evaluated, and is used to accurately measure the ambient temperature of the capacitor when the capacitor is generating heat during operation.

[0100] The real-time output frequency of the inverter to be detected is usually determined by the control board of the inverter to be detected according to the configuration, so the configuration information of the control board is read through the data interface to determine the real-time output frequency.

[0101] Accordingly, the inverter to be detected usually has a fixed configuration of rated output current and rated output frequency, which can be read from the memory to obtain the above data for calculation.

[0102] In one embodiment, in step S3, the estimation result of the remaining life of the capacitor to be estimated includes:

[0103] At least one of an estimated time period life of the capacitor to be estimated in a certain time period in the future, an estimated remaining life of the capacitor to be estimated after a plurality of time periods, and a percentage of the estimated remaining life.

[0104] Specifically, to facilitate on-site maintenance, in this embodiment, in the process of estimating the remaining life of the estimated capacitor, three calibers of output results are selected, including at least one of the estimated time period life of the estimated capacitor in a certain time period in the future, the estimated remaining life of the estimated capacitor after multiple time periods, and the percentage of the estimated remaining life.

[0105] Specifically, in the aging experiment conducted in advance on the capacitor, the total life of the capacitor under the rated output frequency and rated output current can be obtained. Combined with the usual operation and maintenance cycle and other information, multiple equally divided time periods can be divided.

[0106] This time period is usually equal to or slightly shorter than the usual maintenance cycle. The operation and maintenance personnel can learn about the remaining life after several cycles during each maintenance process and set the replacement cycle according to the life number specified in the operation and maintenance requirements.

[0107] Generally speaking, the estimated time period life refers to the number of hours of life left for the capacitor to be evaluated at that time node after reaching a certain number of determination cycles.

[0108] The estimated remaining lifespan refers to the number of hours of lifespan remaining at a time point after a certain number of cycles, determined according to the number of cycles currently set by the operation and maintenance personnel.

[0109] In order to make the judgment process more convenient, the output can also be set in percentage mode, that is, the remaining hours of life at the time node determined after several cycles are proportionally converted to the basic life to obtain a percentage.

[0110] In one embodiment, a method for generating an estimated time period life includes:

[0111]

[0112] Where, L n is the estimated time period life in the nth time period;

[0113] L0 is the basic life of the capacitor to be evaluated;

[0114] con1 is the basic ambient temperature of the capacitor to be evaluated when calibrating its basic life;

[0115] T a is the ambient temperature inside the inverter;

[0116] T ac is the temperature around the capacitor;

[0117] T c is the center temperature of the capacitor.

[0118] Specifically, in order to achieve effective estimation of the life of the capacitor, in this embodiment, an aging experiment is performed on the capacitor to be evaluated in advance, and after the basic life hours are measured, corrections are further made based on the temperature and current parameters in the actual machine environment.

[0119] Specifically, before installation, the basic life hours of the capacitor to be evaluated are calibrated in advance, including controlling the inverter to be tested to output according to the rated frequency and rated output current, and recording the total duration of capacitor failure. After repeated multiple times, the effective life hours are determined as the basic life of the capacitor to be evaluated.

[0120] Accordingly, during the above aging test, the inverter is controlled to be in a specific ambient temperature, on which basis two sets of coefficients are formed, including the ambient temperature during calibration and the actual ambient temperature, the capacitor ambient temperature and the actual capacitor center temperature.

[0121] By adding the capacitor center temperature, the effect of heat accumulation inside the inverter or strong cooling equipment on the temperature rise / fall of the capacitor surface can be effectively measured, thereby effectively measuring the polarization phenomenon inside the capacitor, especially the changes in the electrolyte.

[0122] Combining the above parameters with the basic lifespan, the actual remaining lifespan of the capacitor after a specific period of time in this environment can be effectively estimated.

[0123] In one embodiment, a method for generating an estimated remaining life includes:

[0124]

[0125] Where, L s To estimate the remaining lifespan;

[0126] L0 is the basic life span;

[0127] L n For time period t n Estimated time period life on.

[0128] Specifically, in order to achieve effective estimation of the remaining life in a longer period, in this embodiment, after the current remaining life is calculated, multiple periods are combined to calculate the estimated remaining life.

[0129] Specifically, estimating the remaining lifespan refers to determining the number of hours of lifespan remaining at a time node after a number of cycles based on the number of cycles currently set by the operation and maintenance personnel.

[0130] Normally, the remaining hours of life in each cycle do not change much in a short cycle; however, for some long-term operation, especially for inverter equipment that needs to run for a long time in summer and winter, the remaining life between cycles varies greatly. The remaining life can be calculated differently according to information such as ambient temperature under different working conditions. In the overall calculation process, a sequence of life over multiple cycles is formed for processing.

[0131] In one embodiment, a method for generating an estimated percentage of remaining life includes:

[0132]

[0133] Where, L% is the percentage of estimated remaining life;

[0134] L s To estimate the remaining lifespan;

[0135] L0 is the basic life span.

[0136] Specifically, to facilitate the operation and maintenance personnel to handle, in this embodiment, after the estimated time period life is calculated, the percentage of the estimated remaining life is also converted based on the basic life for easy display.

[0137] A detection system for implementing the above-mentioned method for detecting the remaining life of an electrolytic capacitor of a frequency converter;

[0138] like Figure 3 As shown, the detection system includes:

[0139] A first temperature sensor 1A, the first temperature sensor 1A is arranged at the air inlet of the inverter to be detected;

[0140] The first temperature sensor 1A collects the ambient temperature inside the inverter;

[0141] The inverter to be tested includes a plurality of capacitors to be evaluated and a control board;

[0142] A second temperature sensor 2A, the second temperature sensor 2A is arranged at a central position between the plurality of capacitors to be evaluated;

[0143] The second temperature sensor 2A collects the temperature around the capacitor;

[0144] A current sensor 3A, the current sensor 3A is arranged at the output end of the frequency converter to be detected;

[0145] The current sensor 3A collects the real-time output current;

[0146] A processing device 4A, the processing device 4A is respectively connected to the first temperature sensor 1A, the second temperature sensor 2A, the current sensor 3A and the control board 5A;

[0147] The processing device 4A obtains the rated output current, rated output frequency and real-time output frequency of the inverter to be detected according to the control board 5A;

[0148] The processing device 4A estimates the remaining life of the capacitor to be estimated based on the ambient temperature inside the inverter, the ambient temperature of the capacitor, the real-time output current, the rated output current, the rated output frequency and the real-time output frequency.

[0149] In one embodiment, the detection system further includes a display screen connected to the processing device;

[0150] The display shows the remaining life.

[0151] Specifically, in order to facilitate related operation and maintenance operations, in this embodiment, a set of display screens is also added to the detection system, and the display screens are connected to the processing device via a video cable. After the processing device calculates the remaining life, it can display it through the display screen.

[0152] Accordingly, after configuring a plurality of calculable remaining lifespans of different dimensions, including the estimated time period lifespan of the capacitor to be estimated in a certain time period in the future, the estimated remaining lifespan of the capacitor to be estimated after multiple time periods, and the percentage of the estimated remaining lifespan.

[0153] To facilitate switching of the display, a corresponding switching button may be provided on the display screen to change the data format output by the processing device, and the display screen inputs corresponding instructions to the processing device through the signal uplink cable.

[0154] Those skilled in the art will appreciate that various aspects of the present invention, or possible implementations of various aspects, may be specifically implemented as systems, methods, or computer program products. Therefore, various aspects of the present invention, or possible implementations of various aspects, may take the form of complete hardware embodiments, complete software embodiments (including firmware, resident software, etc.), or embodiments of combined software and hardware aspects, all collectively referred to herein as "circuits," "modules," or "systems." In addition, various aspects of the present invention, or possible implementations of various aspects, may take the form of computer program products, which refer to computer instructions stored in a memory.

[0155] The memory may be a computer-readable signal medium or a computer-readable storage medium. Computer-readable storage media include but are not limited to electronic, magnetic, optical, electromagnetic, infrared or semiconductor systems, devices or apparatuses, or any suitable combination of the foregoing, such as random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable read-only memory (CD-ROM).

[0156] The processor in the computer reads the computer instructions stored in the memory, so that the processor can execute the functional actions specified in each step or the combination of steps in the flowchart; and generate a device for implementing the functional actions specified in each block or the combination of blocks in the block diagram.

[0157] It should be understood that the processor in the computer can be understood as one or more application-specific integrated circuits (ASICs), DSPs, programmable logic devices (PLDs), complex programmable logic devices (CPLDs), field programmable gate arrays (FPGAs), general-purpose processors, controllers, microcontrollers (MCUs), microprocessors, or other electronic components implemented to execute the aforementioned computer instructions.

[0158] Computer instructions can be executed completely on the user's local computer, partially on the user's local computer, as a separate software package, partially on the user's local computer and partially on a remote computer, or completely on a remote computer or server. It should also be noted that in some alternative embodiments, the functions noted in each step in the flow chart or each block in the block diagram may not occur in the order noted in the figure. For example, depending on the functions involved, two steps or two blocks shown in succession may actually be executed roughly simultaneously, or these blocks may sometimes be executed in reverse order.

[0159] Of course, in actual application, the various components in the computer system are coupled together through the bus system. It can be understood that the bus system is used to realize the connection and communication between these components. In addition to the data bus, the bus system also includes a power bus, a control bus and a status signal bus.

[0160] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting the remaining life of an electrolytic capacitor of a frequency converter, characterized in that: include: Step S1: collecting operating parameters of the frequency converter to be detected, and collecting the ambient temperature of the capacitor to be estimated in the frequency converter to be detected; The inverter operating parameters include real-time output frequency, ambient temperature inside the inverter, and real-time output current; Step S2: estimating the capacitor center temperature of the capacitor to be estimated according to the inverter operating parameters and the ambient temperature of the capacitor; Step S3: estimating the remaining life of the capacitor to be estimated according to the inverter operating parameters, the ambient temperature of the capacitor and the center of the capacitor.

2. The method for detecting the remaining life of an electrolytic capacitor of a frequency converter according to claim 1, characterized in that: In step S2, the method for estimating the center temperature of the capacitor includes: Where, T c is the center temperature of the capacitor; con2 is the capacitor center temperature of the inverter to be tested calibrated at the rated frequency and rated output current; I out is the real-time output current; I outrating is the rated output current; f out is the real-time output frequency; f outrating is the rated output frequency.

3. The method for detecting the remaining life of an electrolytic capacitor of a frequency converter according to claim 2, characterized in that: The step S1 comprises: Step S11: collecting the real-time output current from the current sensor, collecting the ambient temperature inside the inverter from the first temperature sensor, collecting the ambient temperature of the capacitor from the second temperature sensor, and reading the real-time output frequency of the inverter to be detected from the controller; Step S12: extracting the rated output current and the rated output frequency from the memory.

4. The method for detecting the remaining life of an electrolytic capacitor of a frequency converter according to claim 1, characterized in that: In step S3, the estimation result of the remaining life of the capacitor to be estimated includes: At least one of an estimated time period life of the capacitor to be estimated in a certain time period in the future, an estimated remaining life of the capacitor to be estimated after a plurality of time periods, and a percentage of the estimated remaining life.

5. The method for detecting the remaining life of an electrolytic capacitor of a frequency converter according to claim 4, characterized in that: The method for generating the estimated time period life includes: Where, L n is the estimated time period life at the nth time period; L0 is the basic life of the capacitor to be evaluated; con1 is the basic ambient temperature of the capacitor to be evaluated when calibrating the basic life; T a is the ambient temperature inside the inverter; T ac is the ambient temperature of the capacitor; T c is the center temperature of the capacitor.

6. The method for detecting the remaining life of an electrolytic capacitor of a frequency converter according to claim 5, characterized in that: The method for generating the estimated remaining life includes: Where, L s The estimated remaining lifespan is: L0 is the basic life span; L n For time period t n The estimated time period of life is described above.

7. The method for detecting the remaining life of an electrolytic capacitor of a frequency converter according to claim 6, characterized in that: The method for generating the percentage of the estimated remaining life includes: Wherein, L% is the percentage of the estimated remaining life; L s The estimated remaining lifespan is: L0 is the basic life span.

8. A detection system, characterized in that: Used to implement the remaining life detection method of the inverter electrolytic capacitor according to any one of claims 1 to 7; The detection system comprises: A first temperature sensor, wherein the first temperature sensor is arranged at an air inlet of the frequency converter to be detected; The first temperature sensor collects the ambient temperature inside the inverter; The inverter to be tested includes a plurality of capacitors to be evaluated and a control board; a second temperature sensor, the second temperature sensor being arranged at a central position between the plurality of capacitors to be evaluated; The second temperature sensor collects the ambient temperature of the capacitor; A current sensor, wherein the current sensor is arranged at an output end of the frequency converter to be detected; The current sensor collects real-time output current; a processing device, the processing device being respectively connected to the first temperature sensor, the second temperature sensor, the current sensor and the control board; The processing device obtains the rated output current, rated output frequency and real-time output frequency of the inverter to be detected according to the control board; The processing device estimates the remaining life of the capacitor to be estimated based on the ambient temperature inside the inverter, the ambient temperature of the capacitor, the real-time output current, the rated output current, the rated output frequency and the real-time output frequency.

9. The detection system according to claim 8, characterized in that: The detection system further comprises a display screen, wherein the display screen is connected to the processing device; The display screen displays the remaining life.

Images