Printed circuit structure type standard capacitor
By adopting a double-layer printed circuit board structure and new dielectric materials, the problem of small capacity, poor accuracy and stability of standard capacitors is solved, and more efficient, precise and reliable capacitance performance is achieved.
Patent Information
- Application Number
- CN202411654805.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-19
- Publication Date
- 2025-02-18
AI Technical Summary
Existing standard capacitors have small capacity, poor accuracy and stability, making it difficult to meet the needs of high precision and large capacity.
The double-layer printed circuit board structure is adopted, and the electrode area and number of layers are increased through the design of conductive rods and multiple electrode plates. The electrode is protected using a new dielectric material and a polyester film to ensure capacitance accuracy and stability.
It improves the capacity, accuracy and stability of the capacitor, reduces electrode resistance and losses, enhances dielectric strength and constant, and solves the shortcomings of traditional capacitors in high precision and large capacity.
Smart Images
Figure CN119480445A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of circuit electronic components, and in particular to a printed circuit structure type standard capacitor. Background Art
[0002] Standard capacitors (abbreviated as standard capacitors) are widely used as physical measurement standard instruments in power systems, scientific research institutions, substations, power plants, high-voltage measurement, and high-voltage electrical product production and testing. They are important measurement standard instruments for high-voltage capacitive electrical equipment, insulation material capacitance and loss tangent (dielectric loss factor). Standard capacitors have various electrode forms and dielectric materials to meet the needs of different precision and capacity ranges. They are divided into 5 levels from 0.01 to 0.2 according to the accuracy level to meet the needs of different precision measurement. The printed circuit structure standard capacitor discussed here is a standard capacitor for measurement calibration with a capacitance of several hundred picofarads to several thousand picofarads and an accuracy of 0.01.
[0003] The standard capacitor structure is closely related to its capacitance value, electrode form and the medium used. The standard capacitor consists of two metal plates and an insulating medium (dielectric) sandwiched between them. The metal plates are the core components. The distance between the plates and the properties of the medium determine the capacitance value of the standard capacitor. The intermediate medium of the plates usually uses high-purity, low-loss insulating materials such as fused quartz, mica, and gas. Electrodes are mostly made of metals with good conductivity, corrosion resistance, and oxidation resistance, such as silver and copper. When designing the internal structure of the electrode, the electric field distortion and energy loss are minimized, the insulation structure is optimized, and the leakage current between the electrodes is reduced.
[0004] Generally, small-capacity standard capacitors (mostly 100pF and below) often use sealed air and coaxial cylindrical electrode structures, which have the advantage of good stability. If the sealed air is replaced with insulating gas, it can be used at high voltages of hundreds of thousands of volts. The disadvantage is that the capacitance value is difficult to increase.
[0005] The medium capacitance range is 100-1000pF. The standard capacitors for high-precision measurement and calibration are mostly air-insulated and have multi-layer flat electrode structures. Their structure can increase the capacitance parameters within a certain range. The multi-layer flat electrode structure also reduces the stability performance. The annual stability is within 10 －6 ~10 －5 scope.
[0006] The standard capacitors with a capacitance greater than 1000pF are large capacitance capacitors. Since the flat air structure cannot meet the requirements of large capacitance, the mica silver-plated or high-purity fused quartz process is used instead. The loss angle and annual stability of the standard capacitors manufactured by this process are within 10 －5The precision of its manufacturing process has a great influence on the dielectric loss parameters of the standard capacitance, and the electrode plating quality, dielectric purity and thickness need to be strictly controlled, making it difficult to achieve high-precision standard capacitance. At present, due to the development of organic insulating film technology with surface metallization, a large number of small-volume capacitors ranging from tens of picofarads to hundreds of microfarads have also appeared and are widely used.
[0007] In order to improve the accuracy of dielectric loss measurement, the design of standard capacitance electrodes should minimize poor contact and eliminate the influence of stray capacitance. To eliminate stray capacitance interference, metal shielding electrodes are used to shield the standard capacitance, and shielding terminals are connected to the shielding electrodes to fix the interference loop.
[0008] The above shows that optimizing the electrode structure and selecting suitable dielectric materials are the key to reducing dielectric loss and improving the stability of standard capacitance. Driven by the progress of material technology and processing technology, the selection of new dielectric materials with low dielectric loss, high stability and high insulation resistance, easy and controllable use, and precision electrode structure processing technology have become the key to further improving the performance parameters of standard capacitance.
[0009] Factors affecting the standard capacity parameters: The impact of environmental changes on standard capacitors for measurement is a complex and delicate issue, which is the result of the combined effects of multiple environmental factors. These mainly include ambient temperature, humidity, vibration shock, acceleration, and atmospheric pressure. High temperature environments will accelerate chemical or electrochemical reactions in capacitors, accelerate the aging of dielectric materials, and increase capacitor dielectric loss. High temperatures will also accelerate electrons, reduce insulation resistance, and reduce dielectric strength, affecting capacitor dielectric loss. Low temperature environments have relatively little direct impact on capacitor dielectric loss, but extreme low temperatures will cause the internal materials of capacitors to shrink and generate stress, which will also affect their performance over a long period of time.
[0010] In high humidity environment, water vapor penetrates into the interior, corroding the metallization layer, reducing capacity and increasing loss. At the same time, water vapor condenses and is absorbed on the surface, reducing insulation resistance, increasing leakage and arcing risks, and increasing dielectric loss.
[0011] Dynamic environmental factors such as vibration, shock, and acceleration can cause slight changes in its structure, resulting in changes in capacitance and loss values. In addition, lead breakage and poor contact can increase dielectric loss.
[0012] Therefore, factors such as ambient temperature and humidity will accelerate the aging process of the standard capacitor medium, causing changes in the dielectric constant and resistivity of the medium. At the same time, high temperature and high humidity will reduce its insulation resistance, dielectric strength, increase the risk of leakage arcing, and mechanical damage will cause changes in the standard capacitor electrode structure, resulting in poor contact and lead breakage. The above factors will increase the dielectric loss of the standard capacitor and reduce the stability of the capacitor.
[0013] How to increase the single-layer electrode area without increasing the mechanical performance requirements of the metal electrode, increase the number of electrode layers without increasing the electrode assembly and insulation support requirements and maintain reliable electrode structure strength has become a problem to be solved. Summary of the invention
[0014] Multiple aspects of the present application provide a printed circuit structure standard capacitor, which solves the technical problems of small capacity, poor precision and stability of existing standard capacitors.
[0015] In order to achieve the above technical effects, one aspect of the present application provides a printed circuit structure standard capacitor, including: a housing, a connecting wire and a printed circuit structure capacitor, the printed circuit structure capacitor is fixedly arranged in the housing and electrically connected to the socket of the housing through the connecting wire, the printed circuit structure capacitor includes a conductive rod and a plurality of electrode plates, the top and bottom surfaces of each electrode plate are provided with conductive materials, the center and edges of the electrode plate are evenly provided with conductive through holes, the plurality of electrode plates are vertically stacked and arranged in parallel, and the conductive rod passes through the through hole to fix the position of the electrode plate. .
[0016] According to a preferred embodiment of the present invention, the electrode plate is circular, and electrolytic copper foil is provided on the top and bottom surfaces as electrode layers.
[0017] According to a preferred embodiment of the present invention, the surface of the electrode layer is coated with a polyester film.
[0018] According to a preferred embodiment of the present invention, the thickness of the electrode plate is 2.5 mm, and the area of the single-sided electrode layer is not greater than 260*260 mm.
[0019] According to a preferred embodiment of the present invention, a low-voltage shielding electrode is provided on the bottom surface of the electrode plate.
[0020] According to a preferred embodiment of the present invention, the printed circuit structure capacitor includes fifteen electrode plates.
[0021] According to a preferred embodiment of the present invention, a capacitance value fine-tuning circuit is provided on the lowermost electrode plate.
[0022] According to a preferred embodiment of the present invention, the electrode plate material is FR-4 glass fiber reinforced epoxy resin.
[0023] According to a preferred embodiment of the present invention, a sealed chamber is provided inside the housing, and the printed circuit structure capacitor is sealed in the sealed chamber.
[0024] According to a preferred embodiment of the present invention, the housing is an airtight housing, and compressed gas is filled between the housing and the sealed chamber. In the solution provided in the embodiment of the present application, 1) a double-layer printed circuit board structure is adopted, which reduces the mechanical performance requirements of the traditional structure for the metal electrode, reduces the electrode resistance, and uses the substrate as a new dielectric material to improve the dielectric strength and dielectric constant, providing support for improving the performance parameters of standard capacitors. Compared with existing standard capacitors, it is more efficient, precise, stable and reliable.
[0025] 2) The mature production and processing technology of printed circuit boards is used to ensure the design and manufacturing of single-layer electrode patterns, the consistency of multi-layer electrode plate parameters, and the accuracy of multi-layer electrode plate stacking and assembly. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.
[0027] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 A schematic diagram of a printed circuit structure capacitor provided in one embodiment of the present application; Figure 2 A schematic diagram of the top surface structure of a printed circuit structure capacitor electrode plate provided in one embodiment of the present application; Figure 3 A schematic diagram of the bottom surface structure of a printed circuit structure capacitor electrode plate provided in one embodiment of the present application; Figure 4 A schematic diagram of a printed circuit structure capacitor sealing structure provided in one embodiment of the present application; Figure 5 A schematic diagram of a printed circuit structure standard capacitor provided in one embodiment of the present application.
[0028] Among them, 1. Printed circuit structure capacitor; 2. Conductive rod; 3. Electrode plate; 4. Nut; 5. Through hole; 6. Low-voltage shielding electrode; 7. Sealed chamber; 8. Shell; 9. Handle; 10. High-voltage plug port; 11. Low-voltage plug port.
[0029] The same or similar reference numerals in the drawings represent the same or similar components. DETAILED DESCRIPTION
[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0032] The traditional gas-insulated multi-layer flat-plate electrode structure is formed by processing metal sheets with good mechanical properties and is composed of multiple layers of insulating supports. The manufactured standard capacity parameters are determined by the electrode processing and assembly accuracy, and there are many uncontrollable factors.
[0033] Printed circuit board type multi-layer flat electrode, using mature CAD circuit drawing software, can efficiently design various complex electrode patterns and compare and optimize various schemes, which will be completed by perfect automated machinery in the later stage.
[0034] The present application provides a printed circuit structure type standard capacitor, comprising: a housing 8, a connecting wire and a printed circuit structure type capacitor 1.
[0035] Figure 1 A schematic diagram of a printed circuit structure capacitor 1 provided in one embodiment of the present application is shown in FIG. Figure 1 As shown, specifically, the printed circuit structure capacitor 1 includes a conductive rod 2 and a plurality of electrode plates 3, the top and bottom surfaces of each electrode plate 3 are provided with conductive materials, and conductive through holes 5 are evenly provided at the center and edges of the electrode plates 3. The plurality of electrode plates 3 are vertically stacked and arranged in parallel, and the conductive rods 2 pass through the through holes 5 to fix the positions of the electrode plates 3. The printed circuit structure capacitor 1 in the embodiment of the present invention includes fifteen electrode plates 3 stacked vertically, and the plurality of conductive rods 2 pass through the through holes 5 of the electrode plates 3 in sequence, and are fixed at both ends of the conductive rods 2 with nuts 4.
[0036] Figure 2 This is a schematic diagram of the top surface structure of an electrode plate 3 of a printed circuit structure capacitor 1 provided in an embodiment of the present application. Figure 3 A schematic diagram of the bottom surface structure of a printed circuit structure capacitor 1 electrode plate 3 provided in one embodiment of the present application is shown in FIG. Figure 2 and 3As shown, the electrode plate 3 is annular, and the upper and lower conductive layers of a double-layer printed circuit board are used as standard capacitance electrodes. The compressed gas medium in the middle of the electrode is replaced with an insulating inorganic substrate or organic material of a printed circuit board, and its dielectric strength is 6 to 7 times that of the traditional standard capacitance medium air, and its relative dielectric constant is 4 to 5 times that of the traditional one. The new synthetic material used in the epoxy insulating substrate layer of the printed circuit adopts a mature production process, and the size and thickness of the sheet are uniform and controllable. The outer dimensions and fixed apertures of the printed circuit board are precisely processed by CNC machine tools, which solves the problems of insulating support of the two electrode plates 3 of the traditional standard capacitance and installation and fixation of multi-layer electrodes.
[0037] Conductive through holes 5 are evenly arranged in the center and edges of the electrode plate 3. The multilayer board structure is fixed by a three-side and center four-control method. A metal through-hole process is used to solve the connection problem between the multilayer electrode plates 3 and reduce the impact of mechanical damage on the overall multilayer electrode structure.
[0038] The bottom surface of the electrode plate 3 is provided with a low-voltage shielding electrode 6 to eliminate the edge effect of the main electrode and improve the measurement accuracy of the capacitance value. The three through holes 5 on the edge are respectively connected to the high-voltage electrode, low-voltage electrode and shielding electrode of the electrode plate 3. The through holes 5 are provided with threads, which can be fixed with the conductive rod 2 by threaded connection. The designed standard capacitance electrode and shielding and lead patterns are accurately transferred to the conductive layer of the double-layer electrode plate 3 by exposure and development technology, and the excess parts are removed by chemical methods to obtain the electrode shape and size required by the design. A 0.3mm thick electrolytic copper foil is used as the electrode layer, which eliminates the insulation support and the mechanical strength requirements of the electrode material. The electrolytic copper used to ensure the conductive performance of the upper and lower conductive layers of the circuit board can reduce the standard capacitance loss and lead resistance. If necessary, a metal layer such as gold plating or silver plating can be coated on the obtained electrode pattern to further reduce the standard capacitance loss parameter value. The surface of the electrode layer is coated with a polyester film to protect the electrode from the external environment.
[0039] Electrode plates 3 of different materials and thicknesses are selected according to rated voltage and capacity. The material of the electrode plate 3 in the embodiment of the present invention is FR-4 glass fiber reinforced epoxy resin with a thickness of 2.5 mm and a single-layer electrode area of ≤260*260 mm. A capacitance value fine-tuning circuit is provided on the bottom electrode plate 3 to ensure capacitance accuracy requirements.
[0040] Figure 4 A schematic diagram of a sealed structure of a printed circuit structure capacitor 1 provided in one embodiment of the present application is shown in FIG. Figure 4 As shown, a sealed chamber 7 is disposed inside the housing 8 , the printed circuit structure capacitor 1 is sealed in the sealed chamber 7 , and a gap filled with gas is disposed between the sealed chamber 7 and the housing 8 .
[0041] Figure 5 A schematic diagram of a printed circuit structure standard capacitor provided in one embodiment of the present application is shown in FIG. Figure 5 As shown, Figure 4 The sealed structure of the printed circuit structure capacitor 1 is fixedly placed in the shell 8, which is an airtight shell 8. The shell 8 and the sealed chamber 7 are filled with compressed gas to form a positive pressure to prevent water vapor from entering. The printed circuit structure capacitor 1 is electrically connected to the plug port of the shell 8 through a connecting wire, wherein the high-voltage electrode is connected to the center of the high-voltage plug port 10 on the shell 8, the low-voltage electrode is connected to the center of the low-voltage plug port 11 on the shell 8, and the shielding electrode is connected to the outer metal of the low-voltage plug port 11 on the shell 8. Finally, the printed circuit structure capacitor 1 is sealed in the shell 8 to form a printed circuit structure standard capacitor. Two handles 9 are also fixedly provided on the upper part of the shell 8 for easy movement.
[0042] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.
[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.
[0044] In addition, it is clear that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. Multiple units or devices stated in a device claim can also be implemented by one unit or device through software or hardware. The words first, second, etc. are used to indicate names, and do not indicate any particular order.
Claims
1. A printed circuit structure standard capacitor, characterized in that: include: A housing (8), a connecting wire and a printed circuit structure capacitor (1), wherein the printed circuit structure capacitor (1) is fixedly arranged in the housing (8) and electrically connected to a socket of the housing (8) via the connecting wire, and the printed circuit structure capacitor (1) comprises a conductive rod (2) and a plurality of electrode plates (3), wherein the top and bottom surfaces of each electrode plate (3) are provided with conductive material, and conductive through holes (5) are evenly arranged at the center and edges of the electrode plate (3), wherein the plurality of electrode plates (3) are vertically stacked and arranged in parallel, and the conductive rod (2) passes through the through holes (5) to fix the position of the electrode plates (3).
2. The printed circuit structure standard capacitor according to claim 1, characterized in that: The electrode plate (3) is circular, and has electrolytic copper foils as electrode layers on the top and bottom surfaces.
3. The printed circuit structure standard capacitor according to claim 2, characterized in that: The surface of the electrode layer is coated with a polyester film.
4. The printed circuit structure standard capacitor according to claim 1, characterized in that: The electrode plate (3) has a thickness of 2.5 mm, and a single-sided electrode layer area of no more than 260*260 mm.
5. The printed circuit structure standard capacitor according to claim 1, characterized in that: A low-voltage shielding electrode (6) is provided on the bottom surface of the electrode plate (3).
6. The printed circuit structure standard capacitor according to claim 1, characterized in that: The printed circuit structure capacitor (1) comprises fifteen electrode plates (3).
7. The printed circuit structure standard capacitor according to claim 6, characterized in that: A capacitance value fine-tuning circuit is provided on the electrode plate (3) located at the bottom.
8. The printed circuit structure standard capacitor according to claim 1, characterized in that: The electrode plate (3) is made of FR-4 glass fiber reinforced epoxy resin.
9. The printed circuit structure standard capacitor according to claim 1, characterized in that: A sealed chamber (7) is arranged inside the housing (8), and the printed circuit structure capacitor (1) is sealed and arranged in the sealed chamber (7).
10. The printed circuit structure standard capacitor according to claim 9, characterized in that: The shell (8) is an airtight shell (8), and compressed gas is filled between the shell (8) and the sealed chamber (7).