JP2008224533A - Electrolytic capacitor degradation diagnosis system and electrolytic capacitor degradation diagnosis method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolytic capacitor degradation diagnosis system and an electrolytic capacitor degradation diagnosis method for externally diagnosing degradation in an electrolytic capacitor built in a controller, without having to remove it from a circuit, and to quickly, efficiently and automatically diagnose a plurality of the electrolytic capacitors to be diagnosed in the controller. <P>SOLUTION: An estimate equation is previously obtained from a relative relation between a dielectric tangent tan δs in a stand-alone state and a dielectric tangent tan δsm, in a state where a plurality of the electrolytic capacitors 2s with different dielectric tangents are respectively mounted on component circuits 3, and stored. A dielectric tangent tan δm of the to-be-diagnosed capacitor 2 is measured, in a state where it is mounted on the component circuit 3. A dielectric tangent tan δ of the to-be-diagnosed electrolytic capacitor 2 in the stand-alone state is estimated from the measurement value and information for identifying the component circuit 3. The degree of degradation is diagnosed by comparing a previously-stored degradation determination value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrolytic capacitor deterioration diagnosis system and an electrolytic capacitor deterioration diagnosis method for diagnosing the deterioration degree of an electrolytic capacitor.

In the conventional deterioration degree diagnosis of an electrolytic capacitor, the deterioration degree is diagnosed based on the magnitude of current ripple and voltage ripple flowing in the electrolytic capacitor (see, for example, Patent Document 1).
In addition, in the state of the electrolytic capacitor alone, prepare data in which any one of the capacitance, tan δ, and impedance, which are the characteristics of the electrolytic capacitor, is measured in time series, and compare with the measured value of the electrolytic capacitor to be diagnosed. There is also one that diagnoses the degree of deterioration (see, for example, Patent Document 2).

FIG. 5 is a functional block diagram of an electrolytic capacitor deterioration diagnosis system showing the first prior art.
In FIG. 5, 52 is a forward conversion circuit, 53 is an inverse conversion circuit, 54 is an electrolytic capacitor, 55 is a current detection Hall element, 56a is a voltage detection unit, 56b is a current detection unit, 57a and 57b are comparators, 58a, 58b is an AND.
Hereinafter, the function of the electrolytic capacitor deterioration diagnosis system according to the first prior art will be described with reference to FIG.
The voltage detection unit 56a detects a voltage ripple, and the current detection unit 56b detects a current ripple. The comparator 57a compares the detected voltage ripple value with the voltage ripple determination value, and the comparator 57b compares the detected current ripple value with the current ripple determination value.

FIG. 6 is a configuration diagram of an electrolytic capacitor deterioration diagnosis system showing the second prior art.
In FIG. 6, 62 is a diagnostic electrolytic capacitor, 63 is a measurement unit, 64 is a deterioration determination unit, 65 is a database of measured values measured in time series, 66 is a diagnosis unit, and 67 is a determination result display unit.
Hereinafter, the operation of the electrolytic capacitor deterioration diagnosis system according to the second prior art will be described with reference to FIG.
The measurement unit 63 stores the result of measuring the electrical characteristic value of any one of the capacitance, tan δ, leakage current, and impedance of the single electrolytic capacitor 62 in the database 65 in time series.
The deterioration determination unit 64 measures the electrolytic capacitor 62 to be measured in a single state, and compares the measured value with the measurement result stored in the database 65 to determine the deterioration of the electrolytic capacitor.

Thus, in the conventional electrolytic capacitor deterioration diagnosis system, the voltage and current ripple values are compared with the determination values for diagnosis. Alternatively, some electrolytic capacitors are measured in a single state and compared with time-series recorded data for determination.
JP 7-222436 A (page 2-3, FIG. 1) Japanese Patent Laid-Open No. 2002-267708 (page 3, FIG. 1)

However, the conventional electrolytic capacitor deterioration diagnosis system diagnoses the electrolytic capacitor alone, and there is a problem that it cannot be diagnosed when it is incorporated in the control device.
The present invention has been made in view of such problems, and provides an electrolytic capacitor deterioration diagnosis system and an electrolytic method capable of performing deterioration diagnosis from outside the control device without removing the electrolytic capacitor incorporated in the control device from the circuit. An object of the present invention is to provide a capacitor deterioration diagnosis method. It is another object of the present invention to provide an electrolytic capacitor deterioration diagnosis system and an electrolytic capacitor deterioration diagnosis method that automatically and efficiently diagnose a plurality of capacitors to be diagnosed in a control device in a short time.

In order to solve the above problem, the present invention is as follows.
According to the first aspect of the present invention, there is provided a control device including a plurality of constituent circuits having a diagnostic electrolytic capacitor, a measuring instrument for measuring a dielectric tangent of the diagnostic electrolytic capacitor, and a dielectric tangent of the diagnostic electrolytic capacitor. In the electrolytic capacitor deterioration diagnosis system comprising: a personal computer that stores a deterioration determination value and compares a dielectric loss tangent of the electrolytic capacitor to be diagnosed with the deterioration determination value to determine a deterioration degree. The control device has an output unit for measuring the dielectric loss tangent of the diagnostic electrolytic capacitor, and is connected to the output unit when measuring the dielectric loss tangent of the diagnostic electrolytic capacitor via the measurement dedicated jig. An input switching device that switches the plurality of constituent circuits connected to each other and outputs the result to the measurement input unit of the measuring instrument. Based on the dielectric loss tangent measured in advance for a plurality of electrolytic capacitors having different dielectric loss tangents and the dielectric loss tangent measured by the measuring instrument mounted on the plurality of constituent circuits, the computer is configured to have a An estimation formula is obtained and stored for each of the constituent circuits from the correlation with the dielectric loss tangent in the state of being mounted on the constituent circuit, and the measuring instrument is based on the signal from the input switching device. Information for specifying the dielectric tangent of the electrolytic capacitor to be measured measured by the measuring instrument and the constituent circuit at the time of measurement. From the above, the dielectric loss tangent of the electrolytic capacitor to be diagnosed alone is estimated based on the estimation formula, and the deterioration degree is diagnosed by comparing with the deterioration determination value. It is a symptom.

  According to a second aspect of the present invention, in the electrolytic capacitor deterioration diagnosis system according to the first aspect, the personal computer selects the component circuit to be output to the measuring device with respect to the input switching circuit. Instructing the measuring device to start and end measurement of dielectric loss tangent and commanding to transmit data comprising the selected constituent circuit and dielectric loss tangent measurement value, storing the data, and based on the data and the estimation formula And an operation for estimating the dielectric loss tangent of the electrolytic capacitor to be diagnosed alone and determining the deterioration by comparing with the deterioration determination value. .

  Further, the invention according to claim 3 stores the degradation judgment value of the dielectric tangent alone for each specification electrolytic capacitor, and compares the dielectric loss tangent of the diagnostic electrolytic capacitor with the degradation judgment value to judge the degree of degradation. In a method for diagnosing electrolytic capacitor degradation in a control device including a plurality of constituent circuits having a diagnostic electrolytic capacitor, a first dielectric loss tangent alone using a plurality of electrolytic capacitors having different dielectric loss tangents as a sample in advance. Measuring the second dielectric loss tangent in a state in which the plurality of different dielectric loss tangent electrolytic capacitors are mounted on the component circuit in advance, and the first circuit for all the component circuits in advance. Obtaining and storing an estimation equation from the correlation between the dielectric loss tangent and the second dielectric loss tangent, and calculating the dielectric loss tangent of the diagnostic electrolytic capacitor The estimation of the dielectric loss tangent of the diagnostic electrolytic capacitor as a single unit from the step of measuring while attached to the circuit, and the information specifying the measured dielectric loss tangent of the diagnostic electrolytic capacitor and the component circuit at the time of measurement And a step of diagnosing the degree of deterioration by comparing the estimated dielectric loss tangent of the electrolytic capacitor to be diagnosed with the deterioration judgment value.

  Further, the invention of claim 4 is the electrolytic capacitor degradation diagnosis method according to claim 3, wherein the step of measuring the dielectric loss tangent of the electrolytic capacitor to be diagnosed while being mounted on the constituent circuit is measured. The step of estimating the dielectric loss tangent of the diagnostic electrolytic capacitor alone based on the estimation equation from the information specifying the dielectric tangent of the diagnostic electrolytic capacitor and the constituent circuit at the time of measurement, and the estimated diagnostic electrolytic capacitor single time The step of diagnosing the degree of deterioration by comparing the dielectric loss tangent of the capacitor and the deterioration judgment value, in accordance with a predetermined order, and the step of automatically repeating the number of the constituent circuits equipped with the diagnostic electrolytic capacitor It is characterized by.

  According to the first aspect of the present invention, it is possible to obtain an electrolytic capacitor deterioration diagnosis system that enables deterioration diagnosis from outside the control device without removing the electrolytic capacitor incorporated in the control device from the circuit.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, electrolytic capacitor deterioration diagnosis for automatically and efficiently diagnosing a plurality of capacitors to be diagnosed in the control device in a short time. A system is obtained.

  According to the third aspect of the present invention, there is obtained an electrolytic capacitor deterioration diagnosis method that allows deterioration diagnosis from outside the control device without removing the electrolytic capacitor incorporated in the control device from the circuit.

  According to the invention described in claim 4, in addition to the effect of the invention described in claim 3, electrolytic capacitor deterioration diagnosis that automatically and efficiently diagnoses a plurality of capacitors to be diagnosed in the control device in a short time. A method is obtained.

  Hereinafter, specific examples of the method of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of an electrolytic capacitor deterioration diagnosis system showing a first embodiment of the present invention.
In FIG. 1, 1 is a control device, 2 is an electrolytic capacitor to be diagnosed, 3 is a component circuit, 4 is a measurement jig, 5 is an input switching device, and 6 is an LCR meter for measuring the dielectric loss tangent of the electrolytic capacitor. , 7 is a personal computer, 8 is an output terminal, 9 is a measurement cable, 10 is an RS232C communication cable, 11 is a communication terminal, and 15 is an output unit.
Hereinafter, the configuration of the electrolytic capacitor deterioration diagnosis system of the present embodiment will be described with reference to FIG.
The control device 1 includes a plurality of constituent circuits 3 in which a diagnostic electrolytic capacitor 2 is incorporated.
The dedicated measurement jig 4 facilitates connection between the plurality of component circuits 3 and the input switching device 5.
The output terminal 8 of the input switching device 5 is input to the measuring instrument 6 through the measurement cable 9.
The personal computer 7 is connected to the communication terminal 11 of the measuring instrument 6 and the communication terminal 11 of the input switching device 5 by an RS232C communication cable 10. In addition, the personal computer 7 stores a deterioration determination value of the dielectric loss tangent tan δ for each diagnostic electrolytic capacitor 2 having different specifications.

FIG. 2 is a flowchart of the electrolytic capacitor deterioration diagnosis method according to the first embodiment of the present invention, showing a processing procedure for estimating the dielectric loss tangent tan δ of the diagnostic electrolytic capacitor 2 incorporated in the control device 1. .
Hereinafter, the electrolytic capacitor deterioration diagnosis method of the present invention will be described in order with reference to FIGS. In addition, as a symbol of dielectric loss tangent, the dielectric loss tangent of the diagnostic electrolytic capacitor 2 as a single unit is tan δ, the dielectric loss tangent measured with the diagnostic electrolytic capacitor 2 mounted on the constituent circuit 3 is tan δm, and electrolysis of a plurality of different dielectric loss tangents. Using a capacitor as a sample, the dielectric loss tangent of the single unit is tan δs, that is, when n, tan δs1, tan δs2... Tan δsn, each of which is measured with a plurality of electrolytic capacitors having different dielectric loss tangents as samples. The tangent dielectric loss tangent is tan δsm, that is, tan δsm1, tan δsm2,.
First, in step ST1, a plurality of different dielectric loss tangent electrolytic capacitors are used as samples to measure the dielectric loss tangent tan δs alone, and in step ST2, the control device 1 and the input switching device 5 are connected using the measuring tool 4. Then, the dielectric tangent tan δsm is measured with respect to a plurality of electrolytic capacitors having different dielectric loss tangents from the terminal output 8 of the input switching device 5 with the measuring device 6 for all the structural circuits 3, and all the structural circuits are measured in step ST3. For each of the three, an estimation formula of tan δ is obtained from the correlation between the dielectric loss tangent tan δs and the dielectric loss tangent tan δsm and stored. That is, a plurality of tan δsm, which are measurement results external to the control device 1 affected by the resistance of the sample electrolytic capacitor alone, tan δs of the component circuit 3, resistance, resistance of the measurement dedicated jig 4, and input switching device 5, in advance. Based on the correlation, an estimation formula of tan δ relating to tan δ of the electrolytic capacitor 2 to be diagnosed and the measurement result tan δsm outside the control device is created as follows.
Estimation formula of tan δ = (tan δsm−D) / A, where D and A are constants.
The estimation formula created in this way has been confirmed by experiments to have a contribution rate close to 1 (usually 0.98 or more), and is a statistically reliable estimation formula.
Next, in step ST4, the control device 1 and the input switching device 5 are connected by the measuring tool 4 for measurement, and the dielectric tangent of the diagnostic electrolytic capacitor 2 is configured from the terminal output 8 of the input switching device 5 by the measuring device 6. Measurement is performed with the circuit 3 mounted. The tan δ of the diagnostic electrolytic capacitor 2 itself is tan δm, which is a measurement result outside the control device, under the influence of the capacitance and resistance of the constituent circuits, the resistance of the measurement dedicated jig 4 and the input switching device 5.
Next, in step ST5, the dielectric loss tangent tan δ of the diagnostic electrolytic capacitor 2 alone is estimated from the information such as the measured dielectric loss tang tan δm of the electrolytic capacitor 2 to be diagnosed and the component circuit number for specifying the component circuit 3 at the time of measurement. Substitute into an expression
Next, in step ST6, the degree of deterioration is diagnosed by comparing the estimated dielectric loss tangent tan δ of the electrolytic capacitor 2 to be diagnosed with the deterioration determination value of the target capacitor stored in advance.
In step ST7, the diagnosis result is displayed on a screen or printed out.
The above steps ST4 to ST7 are repeated as many times as the number of component circuits 3 on which the diagnostic electrolytic capacitor 2 is mounted.

FIG. 3 is an explanatory diagram of an estimation formula creation method in the electrolytic capacitor deterioration diagnosis system according to the first embodiment of the present invention.
In FIG. 3, 2s is a sample electrolytic capacitor, 13 is data of dielectric loss tangent tan δs measured with the sample electrolytic capacitor alone, 14 is data of dielectric loss tangent tan δsm of the sample electrolytic capacitor 2s measured at the output terminal 8 of the input switching device 5, Is an estimation formula for each constituent circuit of the dielectric loss tangent tan δ. The same reference numerals as those in FIG. 1 indicate the same components as those in FIG. 1, and the description thereof is omitted.
Hereinafter, a method for creating an estimation formula for the dielectric loss tangent tan δ in the electrolytic capacitor deterioration diagnosis system of the present embodiment will be described with reference to FIG.
First, a plurality of sample electrolytic capacitors 2s (for example, n C1, C2,... Cn) having different dielectric loss tangents tan δs are prepared, the dielectric loss tangent is measured by the measuring device 6, and the dielectric loss tangent of the sample electrolytic capacitor 2s alone. A plurality of data tan δs 13 (tan δs1, tan δs2,... tan δsn) are obtained.
Next, a sample electrolytic capacitor 2s (C1, C2,...) Having previously measured the dielectric loss tangent tan δs alone at the mounting position of the diagnostic electrolytic capacitor 2 of the component circuit 3 having the diagnostic electrolytic capacitor 2 of the control device 1. The dielectric loss tangent measured in the state where Cn) is mounted in order, the measurement dedicated jig 4 for connecting the output part of the component circuit 3 of the control device 1 and the input switching device 5 is mounted, and mounted on the control device 1 by the measuring device 6 A plurality of tan δ sm data 14 (tan δ sm1, tan δ sm2,... tan δ smn) are obtained.
Tan δs data 13 (tan δs1, tan δs2,. From the above correlation, an estimation formula 16 for estimating the dielectric loss tangent tan δ when the diagnostic electrolytic capacitor 2 alone is obtained from the dielectric loss tangent tan δm measured with the diagnostic electrolytic capacitor 2 mounted on the control device. This is repeated by the number of component circuits 3, and the estimation formula is stored together with the identification number of the component circuit 3.
As described above, the electrolytic capacitor deterioration diagnosis system according to the present embodiment obtains the estimation equation 16 from tan δs of the sample capacitor 2s alone and tan δm actually measured through the constituent circuit 3 and the measurement dedicated cable 4. The component circuit 3 can also estimate tan δ of the electrolytic capacitor 2 to be diagnosed, and since the contribution rate is close to 1 as described above, it is possible to estimate with high reliability.
In this example, a plurality of different dielectric loss tangent electrolytic capacitors were used as samples. However, a single tan δ was changed by connecting a resistance, for example, about 0.1 ohm to 1 ohm in series with one electrolytic capacitor. You may use what you did as a sample.

In this embodiment, among the electrolytic capacitor deterioration diagnosis processing procedure in the first embodiment, steps ST4 to ST7 are automatically repeated for the number of component circuits 3 on which the electrolytic capacitor 2 to be diagnosed is mounted. is there.
FIG. 4 is an explanatory diagram of the processing procedure of the electrolytic capacitor deterioration diagnosis method according to the second embodiment of the present invention.
In FIG. 4, 12 is a storage device, 18 is a tan δ estimation unit of the electrolytic capacitor to be diagnosed, 20 is a deterioration determination unit, 21 is an output unit, 22 is a program, 23 is a circuit switching control unit, 24 is measurement on / off and data A transmission command, 26 is a component circuit and measurement data, 27 is an estimation formula for each component circuit, and 28 is a deterioration determination value for each specification of the electrolytic capacitor. The same reference numerals as those in FIG. 1 indicate the same components as those in FIG. 1, and the description thereof is omitted.
Hereinafter, the processing procedure of the electrolytic capacitor deterioration diagnosis method of the present embodiment will be described with reference to FIG.
First, when diagnosis is started, circuit switching control is performed by the program 22 of the personal computer 7, the first component circuit 3 is selected, and a measurement on / off and data transmission command 24 is sent to the measuring instrument 6. The data of the dielectric loss tangent measured by the measuring device 6 is stored in the storage device 12 of the personal computer 7 as the configuration circuit and measurement data 26 together with the configuration circuit number 25 assigned to each configuration circuit 3.
Next, the diagnosing electrolytic capacitor tan δ estimation unit 18 reads out the constituent circuit, the measurement data 26 and the estimation formula 27 for each constituent circuit that has been created and stored in advance according to the procedure described in the first embodiment. Tan δ of 2 is estimated.
Next, the deterioration determination unit 20 reads the deterioration determination value 28 for each specification of the electrolytic capacitor from the storage device 12 and determines the deterioration of the diagnostic electrolytic capacitor 2.
The above operation is automatically executed by the number of component circuits 3 on which the electrolytic capacitors to be diagnosed are mounted, and the output unit 21 displays the determination result on the screen or prints it out.

  As described above, the electrolytic capacitor deterioration diagnosis system and the electrolytic capacitor deterioration diagnosis method according to the present embodiment take the procedure of automatically diagnosing the number of component circuits 3 on which the electrolytic capacitor 2 to be diagnosed is mounted. can do.

  The electrolytic capacitor deterioration diagnosis system and the electrolytic capacitor deterioration diagnosis method according to the present invention take a procedure of making an estimation formula under conditions including all the factors to change the measured electrolytic capacitor and various measured values up to the measurement point. It can also be applied to electrolytic capacitors built into component circuits, and can be used to create estimation formulas that have a statistically high contribution rate, so the life deterioration diagnosis function is built into the electrolytic capacitors of new products and existing control panels. It can also be used for such purposes. It is suitable for preventive diagnosis devices for both new and existing control panels having electrolytic capacitors.

1 is a configuration diagram of an electrolytic capacitor deterioration diagnosis system showing a first embodiment of the present invention. The flowchart of the electrolytic capacitor degradation diagnostic method which shows 1st Example of this invention. Explanatory drawing of the estimation formula preparation method in the electrolytic capacitor degradation diagnostic system which shows 1st Example of this invention Explanatory drawing of the process sequence of the electrolytic capacitor degradation diagnostic method which shows 2nd Example of this invention. Functional block diagram of the electrolytic capacitor deterioration diagnosis system showing the first prior art Configuration diagram of electrolytic capacitor deterioration diagnosis system showing the second prior art

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control apparatus 2 Electrolytic capacitor to be diagnosed 2s Sample electrolytic capacitor 3 Configuration circuit 4 Jig for measurement 5 Input switching device 6 Measuring instrument 7 Personal computer 8 Output terminal 9 Measurement cable 10 Communication cable 11 Communication terminal 12 Storage device 13 Sample electrolysis Tan δs data measured by a single capacitor 14 tan δsm data measured at the output terminal 8 of the input switching device 5 15 output unit 16, 27 estimation formula for each constituent circuit 18 tan δ estimation unit 20, 64 degradation determination unit of the electrolytic capacitor to be diagnosed 21 Output unit 22 Program 23 Circuit switching control unit 24 Measurement on / off and data transmission command 26 Configuration circuit and measurement data,
28 Degradation judgment value for each specification of electrolytic capacitor 52 Forward conversion circuit 53 Reverse conversion circuit 54 Electrolytic capacitor 55 Hall element for current detection 56a Voltage detection unit 56b Current detection unit 57a, 57b Comparator 58a, 58b AND
62 Electrolytic capacitor to be diagnosed 63 Measuring unit 65 Database 66 Diagnosing unit
67 Judgment result display

Claims (4)

A control device (1) comprising a plurality of constituent circuits (3) having a diagnostic electrolytic capacitor (2);
A measuring instrument (6) for measuring the dielectric loss tangent (tan δ) of the diagnostic electrolytic capacitor (2);
The deterioration determination value of the dielectric loss tangent (tan δ) of the diagnostic electrolytic capacitor (2) is stored, and the deterioration degree is determined by comparing the dielectric loss tangent (tan δ) of the diagnostic electrolytic capacitor (2) with the deterioration determination value. A personal computer (7);
In the electrolytic capacitor degradation diagnosis system with
The controller (1) has an output unit (15) for measuring a dielectric loss tangent (tan δ) of the diagnostic electrolytic capacitor (2) included in the plurality of constituent circuits (3),
A measurement-dedicated jig (4) connected to the output unit (15) at the time of dielectric loss tangent (tan δ) measurement of the diagnostic electrolytic capacitor (2);
An input switching device (5) for switching the plurality of component circuits (3) connected via the measurement-dedicated jig (4) and outputting the result to the measurement input unit of the measuring instrument (6). ,
The personal computer (7) is mounted in advance on the measuring device (6) by attaching a dielectric tangent (tan δs) measured separately for a plurality of electrolytic capacitors (2s) having different dielectric tangents and the plurality of constituent circuits (3). Based on the dielectric loss tangent (tan δsm) measured in Step 1, an estimation equation is obtained from the correlation between the dielectric tangent (tan δs) of the single unit and the dielectric loss tangent (tan δsm) mounted on each of the component circuits (3). Each of the constituent circuits (3) is obtained and stored,
The measuring instrument (6) determines an electrostatic tangent (tan δm) of the diagnostic electrolytic capacitor (2) in a state of being mounted on the component circuit (3) based on a signal from the input switching device (5). Measure and
The personal computer (7) uses the dielectric tangent (tan δm) of the electrolytic capacitor to be diagnosed (2) measured by the measuring instrument (6) and the information to specify the component circuit (3) at the time of measurement. An electrolytic capacitor deterioration diagnosis system characterized by diagnosing the degree of deterioration by estimating a dielectric loss tangent (tan δ) of a capacitor (2) alone based on the estimation formula and comparing it with the deterioration determination value. The personal computer (7)
Selecting the component circuit (3) to be output to the measuring instrument (6) with respect to the input switching circuit (5);
An operation for instructing the measuring device (6) to start and end measurement of dielectric loss tangent, and a command to transmit data comprising the selected component circuit (3) and dielectric loss tangent measurement value, and storing the data;
An operation of estimating a dielectric loss tangent (tan δ) when the diagnostic electrolytic capacitor (2) is single based on the data and the estimation formula, and determining deterioration by comparing with the deterioration determination value is automatically performed in the component circuit. The electrolytic capacitor deterioration diagnosis system according to claim 1, further comprising a program (22) for executing the number of (3). Stores the degradation judgment value of dielectric tangent (tan δ) for each specification electrolytic capacitor alone,
A procedure for determining the degree of deterioration by comparing the dielectric loss tangent (tan δ) of the electrolytic capacitor to be diagnosed (2) and the deterioration determination value;
In the electrolytic capacitor deterioration diagnosis method in the control device (1) including a plurality of constituent circuits (3) having the electrolytic capacitor to be diagnosed (2),
Measuring a first dielectric loss tangent (tan δs) alone using a plurality of electrolytic capacitors (2s) having different dielectric loss tangents as a sample in advance (ST1);
Measuring a second dielectric loss tangent (tan δsm) in a state where the plurality of different dielectric loss tangent electrolytic capacitors (2s) are mounted on the component circuit (3) in advance (ST2);
For all the constituent circuits (3), a step (ST3) for obtaining and storing an estimation formula from the correlation between the first dielectric loss tangent (tan δs) and the second dielectric loss tangent (tan δsm);
Measuring the dielectric loss tangent (tan δm) of the diagnostic electrolytic capacitor (2) while being attached to the component circuit (3) (ST4);
From the measured dielectric loss tangent (tan δm) of the electrolytic capacitor to be diagnosed (2) and the information specifying the component circuit (3) at the time of measurement, the dielectric loss tangent (tan δ) of the diagnostic electrolytic capacitor (2) alone is estimated. Estimating based on the equation (ST5);
A step (ST6) of diagnosing the degree of deterioration by comparing the estimated dielectric loss tangent (tan δ) when the electrolytic capacitor to be diagnosed (2) alone and the deterioration determination value (ST6). Diagnosis method.   The step (ST4) of measuring the dielectric loss tangent (tan δm) of the diagnostic electrolytic capacitor (2) while attached to the component circuit (3), and the measured dielectric loss tangent of the diagnostic electrolytic capacitor (2) Step (ST5) for estimating a dielectric loss tangent (tan δ) when the diagnostic electrolytic capacitor (2) is single from the information for specifying (tan δm) and the constituent circuit (3) at the time of measurement, and estimation The step of diagnosing the degree of deterioration by comparing the dielectric loss tangent (tan δ) when the electrolytic capacitor to be diagnosed (2) alone and the deterioration determination value (ST6) according to a predetermined order 4. The electrolytic capacitor inferiority according to claim 3, further comprising the step of automatically repeating the number of the component circuits (3) having (2) mounted thereon. Diagnostic methods.

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