A low temperature rise film capacitor and control method thereof

Abstract

The present invention relates to the technical field of capacitors, and in particular to a low-temperature-rise film capacitor and a control method thereof, comprising: a shell, a cavity arranged inside the shell, a capacitor core group, a laminated busbar provided with a positive busbar, a negative busbar, a positive terminal, a negative terminal and an insulating sheet, and a cover plate provided with a spoiler column. The present invention determines an optimal operating temperature range and determines an initial temperature and an initial water flow rate of cooling water according to the temperature control temperature by performing operating temperature rise detection on the film capacitor and generating an analysis image; when it is determined according to the temperature rise time that the temperature control effect of the film capacitor does not meet the preset standard, the reason for not meeting the preset standard is confirmed, or, whether the temperature control effect of the film capacitor meets the preset standard is secondarily determined according to the loss angle tangent value; the operation of the film capacitor is completed based on the condition that the temperature control effect meets the preset standard, thereby improving the working efficiency of the film capacitor.

Description

Technical Field

[0001] The present invention relates to the technical field of capacitors, and in particular to a low-temperature rise film capacitor and a control method thereof. Background Art

[0002] Film capacitors are capacitors with plastic film as dielectric, which have high stability, low loss, long life and excellent frequency characteristics. They are widely used in electronic circuits, especially in situations where high reliability, high performance and high precision are required.

[0003] Low temperature rise refers to the local or overall temperature rise caused by the continuous change of internal current during the operation of equipment or electronic components, but the increase is relatively small, thus maintaining a relatively safe temperature range. This feature is crucial to ensure the stable operation of the equipment and extend its service life.

[0004] Chinese Patent Publication No.: CN118891693A discloses a thin film capacitor. The thin film capacitor of the present invention is a thin film capacitor fixed to a shell, and comprises: a capacitor element, which has a laminate of a dielectric film and an internal electrode, and end surface electrodes formed on one end surface and the other end surface of the laminate; a laminate film, which has a covering portion covering the capacitor element, and a flange portion extending from the outer edge of the covering portion; a terminal electrode, which is connected to the end surface electrode of the capacitor element inside the laminate film and exposed to the outside of the laminate film; and a fixing member, which is a member for fixing to the shell, and has a main body portion arranged along the capacitor element inside the laminate film, and a fixing portion extending from the main body and exposed to the outside of the laminate film.

[0005] It can be seen that although the above technical solution describes the structure of the film capacitor, the heat generated inside the film capacitor cannot be quickly dissipated by the outer shell, which will have an adverse effect on the performance and life of the capacitor, thereby leading to the problem of low working efficiency of the film capacitor. Summary of the invention

[0006] To this end, the present invention provides a low-temperature rise film capacitor and a control method thereof, so as to overcome the problem in the prior art that the heat generated inside the film capacitor cannot be quickly dissipated by the outer shell, which will have an adverse effect on the performance and life of the capacitor, thereby leading to low working efficiency of the film capacitor.

[0007] To achieve the above object, the present invention provides a low temperature rise film capacitor, comprising:

[0008] The shell comprises a cavity arranged inside the shell and having an opening communicating with one side of the shell, a water inlet arranged on one side of the bottom of the shell, and a water outlet arranged on the other side of the bottom of the shell;

[0009] A capacitor core group, which is arranged inside the cavity and consists of a plurality of capacitor cores;

[0010] A stacked busbar, which is connected to the capacitor core group, includes a positive busbar, a negative busbar, a positive terminal, a negative terminal and an insulating sheet, wherein the positive busbar is respectively attached to the positive electrodes of the plurality of capacitor cores, the negative busbar is respectively attached to the negative electrodes of the plurality of capacitor cores, the positive busbar and the negative busbar are stacked through the insulating sheet, the upper portion of the positive terminal is attached to the side of the positive busbar, and the lower portion of the positive terminal is extended perpendicularly to the positive busbar, the upper portion of the negative terminal is attached to the side of the negative busbar, and the lower portion of the negative terminal is extended perpendicularly to the negative busbar;

[0011] The cover plate is arranged on the upper surface of the shell to cover the opening on the upper surface of the shell.

[0012] On the other hand, the present invention also provides a control method for a film capacitor with low temperature rise, comprising:

[0013] Performing several working temperature rise tests on the film capacitor and generating corresponding analysis images respectively, and sequentially obtaining image information from the initial contact resistance value to the preset contact resistance value of the film capacitor;

[0014] Determine the corresponding optimal working temperature range according to each image information, obtain the temperature control temperature according to the maximum value of the optimal working temperature range, and determine the initial temperature and initial water flow rate of the cooling water;

[0015] Obtain the heating time for the film capacitor to heat up to the corresponding temperature control temperature;

[0016] When it is determined that the temperature control effect of the film capacitor does not meet the preset standard according to the heating time, the reason for not meeting the preset standard is confirmed according to the turbulence cooling evaluation value, or, it is determined whether the temperature control effect of the film capacitor meets the preset standard for the second time according to the loss tangent value, wherein the reason for not meeting the preset standard is that the distance between the turbulence columns exceeds the standard or the flow rate of cooling water is insufficient;

[0017] The film capacitor works based on the condition that the temperature control effect meets the preset standard.

[0018] Furthermore, the analysis image is a two-dimensional coordinate image of the corresponding change relationship between the contact resistance and temperature of the film capacitor during the operation of the film capacitor, and the horizontal axis of the two-dimensional coordinate image is the temperature and the vertical axis is the contact resistance value of the film capacitor.

[0019] Furthermore, the process of determining whether the temperature control effect of the film capacitor does not meet the preset standard according to the temperature rise time includes:

[0020] Compare the heating time with the first preset heating time and the second preset heating time respectively;

[0021] If the heating time is less than the first preset heating time, it is determined that the temperature control effect of the film capacitor does not meet the preset standard and the reason why the temperature control effect of the film capacitor does not meet the preset standard is determined according to the turbulence cooling evaluation value;

[0022] If the heating time is greater than or equal to the first preset heating time and less than the second preset heating time, it is determined that the temperature control effect of the film capacitor does not meet the preset standard and the temperature control effect of the film capacitor is secondarily determined based on the loss tangent value to determine whether it meets the preset standard.

[0023] Further, the reason why the temperature control effect of the film capacitor does not meet the preset standard is determined according to the turbulence cooling evaluation value, wherein:

[0024] If the spoiler cooling evaluation value is less than the preset spoiler cooling threshold, it is determined that the reason why the temperature control effect of the film capacitor does not meet the preset standard is that the distance between the spoiler columns exceeds the standard, and the reduction value of the distance between the spoiler columns is determined according to the difference between the preset spoiler cooling threshold and the spoiler cooling evaluation value, and then the cover plate is replaced;

[0025] If the turbulence cooling evaluation value is greater than or equal to the preset turbulence cooling threshold, it is determined that the reason why the temperature control effect of the film capacitor does not meet the preset standard is that the flow rate of cooling water is insufficient, and the flow rate of cooling water is increased according to the difference between the turbulence cooling evaluation value and the preset turbulence cooling threshold;

[0026] The turbulence cooling evaluation value is the difference between the water inlet flow rate of the cooling water at the water inlet and the water outlet flow rate of the cooling water at the water outlet.

[0027] Further, the water flow rate of the cooling water is increased when the loss tangent value is greater than or equal to the first preset loss tangent value and less than the second preset loss tangent value, and the initial temperature of the cooling water is reduced when the loss tangent value is greater than or equal to the second preset loss tangent value.

[0028] Furthermore, the increase amplitude of the water flow rate is positively correlated with the loss tangent difference value, wherein the loss tangent difference value is the difference between the loss tangent value and the first preset loss tangent value.

[0029] Furthermore, several temperature reduction methods are provided for reducing the initial temperature of the cooling water, and each temperature reduction method has a different reduction range for the initial temperature of the cooling water.

[0030] Furthermore, under preset conditions, several correction methods are set for correcting the initial temperature of the cooling water, and each correction method has a different correction amplitude for the initial temperature of the cooling water; the preset condition is that after increasing the initial temperature of the cooling water, the equivalent series resistance value of the film capacitor is greater than or equal to the preset equivalent series resistance value.

[0031] Compared with the prior art, the beneficial effect of the present invention lies in that the present invention forms a waterway-type shell by means of a cavity arranged inside the shell, a cover plate with spoiler columns, a water inlet and a water outlet. Cooling water flows in from the water inlet, passes through the outer surface of the cavity and flows out from the water outlet, taking away the heat generated by the capacitor core group while maintaining a low operating temperature. The spoiler column design on the cover plate further enhances the heat dissipation effect, and improves the heat dissipation efficiency by increasing the contact area between the cooling water and the cover plate and disrupting the water flow. In addition, the temperature control effect of the film capacitor is tested by the heating time and the loss tangent value, thereby improving the working efficiency of the film capacitor.

[0032] Furthermore, the present invention disrupts the water flow by providing a cover plate with a number of disturbance flow columns evenly distributed on the surface, so that the water flow forms turbulence on the surface of the cover plate, thereby improving the heat exchange efficiency, and reducing the distance between each disturbance column of the next batch according to the difference between the preset disturbance flow cooling threshold and the disturbance flow cooling evaluation value, thereby further increasing the degree of disturbance of the water flow, thereby improving the heat exchange efficiency.

[0033] Furthermore, the present invention is provided with a turbulence cooling evaluation value, which is the flow velocity difference of cooling water between the water inlet and the water outlet. It reflects the direct effect of the turbulence column on the degree of water flow disturbance. By real-time monitoring and evaluation of this indicator, precise control of the heat dissipation effect of the capacitor is achieved.

[0034] Furthermore, the present invention performs several working temperature rise tests on the thin film capacitor. In each test, the temperature change and contact resistance change of the capacitor during operation are recorded, and analysis images corresponding to each working temperature rise test are generated respectively. Through multiple tests and analyses, the laws of temperature change and contact resistance change of the thin film capacitor under different working conditions are obtained, thereby providing reliable data support for the subsequent determination of the optimal working temperature range.

[0035] Furthermore, the present invention determines whether the temperature control effect of the film capacitor meets the preset standard according to the temperature rise time, thereby improving the accuracy of the evaluation.

[0036] Furthermore, the present invention determines the reason why the temperature control effect of the film capacitor does not meet the preset standard according to the turbulence cooling evaluation value and makes a corresponding adjustment strategy, detects in real time and makes targeted adjustments, thereby improving the heat dissipation efficiency.

[0037] Furthermore, the present invention realizes precise control of the increase amplitude of the water flow rate by setting the increase amplitude of the water flow rate to be positively correlated with the loss tangent difference.

[0038] Furthermore, the present invention provides several temperature reduction methods for reducing the initial temperature of the cooling water, and each temperature reduction method reduces the initial temperature of the cooling water to a different extent. Finely controlling the increase in the extent can ensure heat dissipation performance while avoiding noise caused by sudden changes in water flow rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic structural diagram of a low-temperature rise film capacitor according to an embodiment of the present invention;

[0040] Figure 2 It is a front cross-sectional view of the shell, cavity, capacitor core group and cover plate of the low temperature rise film capacitor of the embodiment of the present invention along the AA plane;

[0041] Figure 3 A flow chart of a method for controlling a low temperature rise film capacitor according to an embodiment of the present invention;

[0042] Figure 4 This is a flow chart of an embodiment of the present invention for determining whether the temperature control effect of a film capacitor meets a preset standard according to the heating time;

[0043] In the figure, 1. shell; 13. cavity; 11. water inlet; 12. water outlet; 2. capacitor core group; 31. positive busbar; 32. negative busbar; 33. positive terminal; 34. negative terminal; 35. insulating sheet; 4. cover plate; 41. spoiler column. DETAILED DESCRIPTION

[0044] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0045] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0046] It should be pointed out that the data in this embodiment are obtained by comprehensive analysis and evaluation of the historical test data of the present invention three months before this test and the corresponding historical test results. It can be understood by those skilled in the art that the method of the present invention can determine the above parameters for a single item by selecting the value with the highest proportion as the preset standard parameter according to the data distribution, using weighted summation to use the obtained value as the preset standard parameter, substituting each historical data into a specific formula and using the value obtained by the formula as the preset standard parameter or other selection methods, as long as the method of the present invention can clearly define the different specific situations in the single determination process through the obtained values.

[0047] See also Figure 1 , Figure 2 , Figure 3 as well as Figure 4 As shown, they are respectively a schematic diagram of the structure of a film capacitor with low temperature rise according to an embodiment of the present invention; a front view cross-sectional view of the shell, cavity, capacitor core group and cover plate of the film capacitor with low temperature rise along the AA plane according to an embodiment of the present invention; a flow chart of a control method of a film capacitor with low temperature rise according to an embodiment of the present invention; a flow chart of determining whether the temperature control effect of the film capacitor meets the preset standard according to the heating time according to an embodiment of the present invention.

[0048] In one aspect, an embodiment of the present invention provides a low temperature rise film capacitor, comprising:

[0049] See also Figure 1 and Figure 2 As shown, the housing 1 comprises a cavity 13 arranged inside the housing 1 and having an opening communicating with one side of the housing 1, a water inlet 11 arranged on one side of the bottom of the housing 1, and a water outlet 12 arranged on the other side of the bottom of the housing 1;

[0050] A capacitor core group 2, which is arranged inside the cavity 13 and consists of a plurality of capacitor cores;

[0051] A stacked busbar, which is connected to the capacitor core group 2, includes a positive busbar 31, a negative busbar 32, a positive terminal 33, a negative terminal 34 and an insulating sheet 35, wherein the positive busbar 31 is respectively fitted with the positive electrodes of the capacitor cores, the negative busbar 32 is respectively fitted with the negative electrodes of the capacitor cores, the positive busbar 31 and the negative busbar 32 are stacked through the insulating sheet 35, the upper part of the positive terminal 33 is fitted with the side of the positive busbar 31, and the lower part of the positive terminal 33 is extended perpendicularly to the positive busbar 31, the upper part of the negative terminal 34 is fitted with the side of the negative busbar 32, and the lower part of the negative terminal 34 is extended perpendicularly to the negative busbar 32;

[0052] The cover plate 4 is disposed on the upper surface of the housing 1 to cover the opening on the upper surface of the housing 1 .

[0053] Specifically, a plurality of flow-interference columns 41 are evenly arranged on the surface of the cover plate 4 close to the cavity 13 , and a preset interval of 15 mm is set between each of the flow-interference columns 41 .

[0054] On the other hand, an embodiment of the present invention provides a control method for a thin film capacitor with low temperature rise, comprising:

[0055] Step S1, performing several working temperature rise tests on the thin film capacitor and analyzing the corresponding images respectively, and sequentially obtaining image information of the initial contact resistance value of the thin film capacitor from 10 mΩ to the preset contact resistance value of 25 mΩ;

[0056] Step S2, determining the corresponding optimal working temperature range according to each image information, and obtaining the temperature control temperature of 65°C according to the maximum value of the optimal working temperature range, determining the initial temperature of the cooling water of 20°C and the initial water flow rate of 2m / s;

[0057] Step S3, obtaining the heating time for the film capacitor to heat up to the corresponding temperature control temperature;

[0058] Step S4, when it is determined that the temperature control effect of the film capacitor does not meet the preset standard according to the heating time, the reason for not meeting the preset standard is confirmed according to the spoiler cooling evaluation value, or, whether the temperature control effect of the film capacitor meets the preset standard is determined again according to the loss tangent value, wherein the reason for not meeting the preset standard is that the distance between the spoiler columns 41 exceeds the standard or the flow rate of cooling water is insufficient;

[0059] Step S5, completing the operation of the film capacitor based on the condition that the temperature control effect meets the preset standard.

[0060] Specifically, the analysis image is a two-dimensional coordinate image of the corresponding change relationship between the contact resistance and temperature of the film capacitor during the operation of the film capacitor, wherein the horizontal axis of the two-dimensional coordinate image is the temperature and the vertical axis is the contact resistance value of the film capacitor;

[0061] Perform several working temperature rise tests on the film capacitor and generate contact resistance analysis images corresponding to each working temperature rise test, obtain image information from the initial contact resistance value to the preset contact resistance value of the film capacitor in sequence, and generate a two-dimensional coordinate image based on the corresponding change relationship between the contact resistance and temperature of the film capacitor during the working process of the film capacitor. The two-dimensional coordinate image is a two-dimensional coordinate system with the horizontal axis being the temperature and the vertical axis being the contact resistance value of the film capacitor.

[0062] Specifically, the process of determining whether the temperature control effect of the film capacitor does not meet the preset standard based on the temperature rise time includes:

[0063] The heating time is compared with the first preset heating time of 15 minutes and the second preset heating time of 20 minutes respectively;

[0064] If the heating time is less than the first preset heating time, it is determined that the temperature control effect of the film capacitor does not meet the preset standard and the reason why the temperature control effect of the film capacitor does not meet the preset standard is determined according to the turbulence cooling evaluation value;

[0065] If the heating time is greater than or equal to the first preset heating time and less than the second preset heating time, it is determined that the temperature control effect of the film capacitor does not meet the preset standard, and the temperature control effect of the film capacitor is secondarily determined based on the loss tangent value to determine whether it meets the preset standard.

[0066] Specifically, the reason why the temperature control effect of the film capacitor does not meet the preset standard is determined according to the disturbance cooling evaluation value, among which:

[0067] If the spoiler cooling evaluation value is less than the preset spoiler cooling threshold value of 0.4 m / s, it is determined that the reason why the temperature control effect of the film capacitor does not meet the preset standard is that the distance between the spoiler columns 41 exceeds the standard, and the reduction value of the distance between the spoiler columns 41 is determined according to the difference between the preset spoiler cooling threshold value and the spoiler cooling evaluation value, and then the cover plate 4 is replaced;

[0068] If the turbulence cooling evaluation value is greater than or equal to the preset turbulence cooling threshold, it is determined that the reason why the temperature control effect of the film capacitor does not meet the preset standard is that the flow rate of cooling water is insufficient, and the flow rate of cooling water is increased according to the difference between the turbulence cooling evaluation value and the preset turbulence cooling threshold;

[0069] The turbulence cooling evaluation value is the difference between the water inlet flow rate of the cooling water at the water inlet 11 and the water outlet flow rate of the cooling water at the water outlet 12 .

[0070] The inlet flow rate of the cooling water and the outlet flow rate of the cooling water are obtained by a flow meter.

[0071] Specifically, the water flow rate of the cooling water is increased when the loss tangent value is greater than or equal to the first preset loss tangent value 0.01 and less than the second preset loss tangent value 0.03, and the initial temperature of the cooling water is reduced when the loss tangent value is greater than or equal to the second preset loss tangent value.

[0072] It is understandable that the loss tangent is a parameter that measures the energy loss of a capacitor under the action of an electric field. When a capacitor is connected to an AC circuit, the polarization inside the capacitor will cause part of the electrical energy to be converted into heat energy, and this part of the lost electrical energy is represented by the loss tangent. The smaller the loss tangent, the lower the energy loss of the capacitor and the better the performance.

[0073] In this embodiment, the loss tangent value is obtained by an LCR tester.

[0074] Specifically, the increase amplitude of the water flow rate is positively correlated with the loss tangent difference, wherein the positive correlation is, for example, a linear positive correlation or a nonlinear positive correlation, and the linear slope of the linear positive correlation is not specifically limited. It can be understood that the larger the loss tangent difference is, the larger the increase amplitude of the water flow rate is, and the loss tangent difference is the difference between the loss tangent value and the first preset loss tangent value.

[0075] Specifically, there are several temperature reduction methods for reducing the initial temperature of the cooling water, among which:

[0076] If the loss difference is less than the first preset loss difference of 0.008, the initial temperature of the cooling water is reduced by using a first temperature reduction coefficient of 0.99;

[0077] If the loss difference is greater than or equal to the first preset loss difference and less than the second preset loss difference of 0.016, the initial temperature of the cooling water is reduced using the second temperature reduction coefficient of 0.97;

[0078] If the loss difference is greater than or equal to the second preset loss difference, the initial temperature of the cooling water is reduced by using a third temperature reduction coefficient of 0.95;

[0079] The loss difference is the difference between the loss tangent value and a second preset loss tangent value.

[0080] Specifically, there are several correction methods for the correction of the initial temperature of the cooling water under the preset conditions, among which:

[0081] If the difference in the equivalent series resistance value is less than the first preset resistance difference value of 0.2 mΩ, the initial temperature of the cooling water is corrected to the corresponding value using the first correction coefficient 1.02;

[0082] If the equivalent series resistance difference is greater than or equal to the first preset resistance difference and less than the second preset resistance difference of 0.4 mΩ, the initial temperature of the cooling water is corrected to the corresponding value using the second correction coefficient 1.04;

[0083] If the difference in the equivalent series resistance is greater than or equal to the second preset resistance difference, the initial temperature of the cooling water is corrected to a corresponding value using a third correction coefficient of 1.06;

[0084] The preset condition is that after increasing the initial temperature of the cooling water, the equivalent series resistance value of the film capacitor is greater than or equal to the preset equivalent series resistance value of 2mΩ; the equivalent series resistance value difference is the difference between the equivalent series resistance value and the preset equivalent series resistance value.

[0085] It is understandable that the equivalent series resistance of the film capacitor is an important parameter to measure its energy loss. The change of the equivalent series resistance value indirectly reflects the working state of the water-cooled heat exchange system. The higher the equivalent series resistance value, the greater the energy loss of the capacitor and the higher the heat generation.

[0086] The capacitance of the film capacitor in this embodiment is set to 100 μF, and the preset equivalent series resistance value is selected to be 2 mΩ, but the above values ​​are not limited thereto, and those skilled in the art may also adjust the values ​​according to actual needs.

[0087] In this embodiment, the equivalent series resistance value is obtained by an ESR tester.

[0088] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for controlling a low temperature rise film capacitor, characterized in that: include: Performing several working temperature rise tests on the film capacitor and generating corresponding analysis images respectively, and sequentially obtaining image information from the initial contact resistance value to the preset contact resistance value of the film capacitor; Determine the corresponding optimal working temperature range according to each image information, obtain the temperature control temperature according to the maximum value of the optimal working temperature range, and determine the initial temperature and initial water flow rate of the cooling water; Obtain the heating time for the film capacitor to heat up to the corresponding temperature control temperature; When it is determined that the temperature control effect of the film capacitor does not meet the preset standard according to the heating time, the reason for not meeting the preset standard is confirmed according to the turbulence cooling evaluation value, or, it is determined whether the temperature control effect of the film capacitor meets the preset standard for the second time according to the loss tangent value, wherein the reason for not meeting the preset standard is that the distance between the turbulence columns exceeds the standard or the flow rate of cooling water is insufficient; The work of the film capacitor is completed based on the condition that the temperature control effect of the film capacitor meets the preset standard; The film capacitor is provided with a shell and a cover plate, wherein the shell includes a cavity arranged inside and with an opening communicating with one side of the shell, a water inlet arranged on one side of the bottom of the shell, and a water outlet arranged on the other side of the bottom of the shell; a surface of the cover plate close to the cavity is evenly provided with a number of spoiler columns, and a preset spacing is provided between the spoiler columns.

2. The method for controlling a low temperature rise film capacitor according to claim 1, characterized in that: The analysis image is a two-dimensional coordinate image of the corresponding change relationship between the contact resistance and temperature of the film capacitor during the operation of the film capacitor, and the horizontal axis of the two-dimensional coordinate image is the temperature and the vertical axis is the contact resistance value of the film capacitor.

3. The control method of the low temperature rise film capacitor according to claim 2, characterized in that: The process of determining whether the temperature control effect of the film capacitor does not meet the preset standard based on the temperature rise time includes: Compare the heating time with the first preset heating time and the second preset heating time respectively; If the heating time is less than the first preset heating time, it is determined that the temperature control effect of the film capacitor does not meet the preset standard and the reason why the temperature control effect of the film capacitor does not meet the preset standard is determined according to the turbulence cooling evaluation value; If the heating time is greater than or equal to the first preset heating time and less than the second preset heating time, it is determined that the temperature control effect of the film capacitor does not meet the preset standard and the temperature control effect of the film capacitor is secondarily determined based on the loss tangent value to determine whether it meets the preset standard.

4. The method for controlling a low temperature rise film capacitor according to claim 3, characterized in that: According to the evaluation value of turbulence cooling, the reasons why the temperature control effect of the film capacitor does not meet the preset standard are determined, among which: If the spoiler cooling evaluation value is less than the preset spoiler cooling threshold, it is determined that the reason why the temperature control effect of the film capacitor does not meet the preset standard is that the distance between the spoiler columns exceeds the standard, and the reduction value of the distance between the spoiler columns is determined according to the difference between the preset spoiler cooling threshold and the spoiler cooling evaluation value, and then the cover plate is replaced; If the turbulence cooling evaluation value is greater than or equal to the preset turbulence cooling threshold, it is determined that the reason why the temperature control effect of the film capacitor does not meet the preset standard is that the flow rate of cooling water is insufficient, and the flow rate of cooling water is increased according to the difference between the turbulence cooling evaluation value and the preset turbulence cooling threshold; The turbulence cooling evaluation value is the difference between the water inlet flow rate of the cooling water at the water inlet and the water outlet flow rate of the cooling water at the water outlet.

5. The method for controlling a low temperature rise film capacitor according to claim 4, characterized in that: The water flow rate of the cooling water is increased when the loss tangent value is greater than or equal to the first preset loss tangent value and less than the second preset loss tangent value, and the initial temperature of the cooling water is reduced when the loss tangent value is greater than or equal to the second preset loss tangent value.

6. The method for controlling a low temperature rise film capacitor according to claim 5, characterized in that: The increase amplitude of the water flow rate is positively correlated with the loss tangent difference value, wherein the loss tangent difference value is the difference between the loss tangent value and the first preset loss tangent value.

7. The method for controlling a low temperature rise film capacitor according to claim 6, characterized in that: There are several temperature reduction methods for reducing the initial temperature of the cooling water, and each temperature reduction method has a different reduction range for the initial temperature of the cooling water.

8. The method for controlling a low temperature rise film capacitor according to claim 7, characterized in that: Under preset conditions, several correction methods are set for correcting the initial temperature of the cooling water, and each correction method has a different correction range for the initial temperature of the cooling water; the preset condition is that after increasing the initial temperature of the cooling water, the equivalent series resistance value of the film capacitor is greater than or equal to the preset equivalent series resistance value.

Images