Yüksek gerilim kondansatörü tasarımı ve üç boyutlu yazıcı ile üretimi
High voltage capacitor design and production by using fdm type three dimensional printer
Yazar: SALİH DENİZ UZEL
Danışman: PROF. DR. ÖZCAN KALENDERLİ
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Elektrik Mühendisliği Ana Bilim Dalı / Elektrik Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2019
Konu: Elektrik ve Elektronik Mühendisliği = Electrical and Electronics Engineering

Özet:
Kondansatörler, keşfedildikleri 1745 yılından itibaren bilim ve üretimin odağı olmuşlardır. Günümüzde de nanoteknolojiden yüksek gerilim uygulamalarına kadar geniş bir yelpazede, kondansatörler hakkında farklı ihtiyaçları karşılamaya yönelik araştırmalar, arayışlar devam etmektedir. Üç boyutlu yazma yöntemlerinin geliştirilmesi, malzeme biliminin ilerlemesi ile birlikte elektrik elemanlarının tasarımları ve üretimleri ile ilgili yapılan araştırmalarda üç boyutlu yazıcılar kullanılmaya başlanmıştır. Bu çalışmada, FDM tipi üç boyutlu yazıcı kullanılarak deneylerde ve uygulamalarda kullanılabilir yüksek gerilim kondansatörü üretilmesi amaçlanmıştır. Deney için 2,5 nF kapasiteli, anma gerilimi değeri 30 kV olan düzlemsel kondansatör tasarlanmıştır. FDM yazıcı ile üretimin kalitesinin artırılabilmesi için düzlemsel kondansatör geometrisi seçilmiştir. Bu sayede kondansatörün üretiminde oluşabilecek olası hataların mümkün olduğunca azaltılması amaçlanmıştır. Üretim sürecinin, yazıcı yeteneklerine göre basitleştirilmesi ile birlikte tasarımlar başarılı bir şekilde yaklaşık ölçülerde üretilmiştir. Kondansatörlerin dielektrik malzemesini oluşturan malzemelerin elektriksel özelliklerinin ölçümü için 5 cm çapında farklı kalınlıklarda diskler üretilmiştir. Kondansatörün yalıtkan yüzeyiyle aynı kalınlıkta olan diskler, yağ içinde yapılan delinme gerilimi deneylerinde 30 kV seviyesine kadar dayanmışlardır.  Tasarımı ve çizimi yapılan kondansatörün analitik hesaplarını doğrulama aşamasında; kondansatörün üzerindeki potansiyel ve elektrik alan dağılımının incelenebilmesi amacıyla FEMM 4.2 adlı program kullanılmıştır. Sonlu elemanlar yöntemi ile yapılan analiz yardımıyla kondansatörün elektriksel zorlanma ve sığa değerleri incelenmiştir. Analitik hesapla bulunan sonuçlar ile FEMM 4.2 programıyla yapılan hesapla bulunan sonuçlar, eşit değerler vermiştir. Üretilen kondansatörlerin ölçülen kapasite değerleri ile analitik olarak hesaplanan değerleri arasındaki bağıl fark %5'e kadar düşürülmüştür. Kondansatörler, 50 Hz alternatif gerilim altında 50 kV seviyesine kadar denenmiştir. Bu seviyede 2,5 nF'lık kondansatörlerde delinme yaşanmamıştır. Deneyler başarı ile sonuçlanmıştır. Deneyler sonucu elde edilen değerler ile analitik olarak hesapalanan değerler arasındaki farka; kondansatör tasarımlarda oluşan yapısal bozukluklar neden olmuştur. Üretilen kondansatörlerin baskı kalitesindeki olumlu artış ile daha verimli sonuçlar elde edildiği deneyler sonucunda gözlemlenmiştir. Tasarımda ve üretimde bir takım iyileştirmeler gerekmesine rağmen; araştırmada yapılması amaçlanan hedefler başarılı bir şekilde gerçeklenmiştir. Bu sayede üç boyutlu yazıcı ile bir elektrik elemanının yapılabilirliği gösterilmiş ve gelecekte yapılacak çalışmalar, yenilikçi fikirler için tanıtım gerçekleştirilmiştir.

Abstract:
Capacitors have been the focus of the science and the production since it was discovered in 1745. Today, researches are carried out to provide for the different needs about capacitors in a wide range from nanotechnology to high voltage applications. With the development of three-dimensional printing methods and the advancement of materials science, three-dimensional printers have been started to be used in the researches about the design and production of electrical elements. In the field of study on capacitors, researches are generally being carried out on the production of super-capacitors with 3D printers.  In this study, it is aimed to produce high voltage capacitor which can be used in experiments and applications by using FDM type three dimensional printer. The aim of this study is to investigate the usability of the 3d printed electrical elements. For research; capacitors, frequently used in electrical engineering were selected. The properties of the capacitor, which needed, vary according to the area of use. Therefore, a wide variety of production and design methods are available. Due to its wide range of applications, the demand for capacitors always continues. For this reason, 3 dimensional priters have been used in order to provide easy and individual production of capacitors in a short time.  In the study, in order to determine the electrical properties of the material used by FDM type printer where capacitor designs will be printed, material test samples and 2.5 nanofarad high voltage capacitor design has been made. The properties of the designs will have been tested in the high voltage laboratory. For the experiments, a 2.5 nF high voltage capacitor with a rated voltage of 30 kV was designed. Capacitor geometry was chosen as planar capacitor geometry. Planar capacitor geometry was selected to improve the production quality of FDM printer. In this way, it is aimed to reduce possible errors in the production of the capacitor as much as possible. Planar capacitor design was drawn with computer-aided 3D drawing program. The dimensions of the 2.5 nF capacitor design were determined according to the printing settings of the three-dimensional printer. With the simplification of the manufacturing process according to printer capabilities, designs have been successfully produced to approximate dimensions. To measure the electrical properties of the materials which is also the dielectric material of the capacitors, discs with 5 cm diameter were produced in different thickness. In the production of capacity and discs ABS and PLA materials were used. Powdered iron shavings were used as conductors in the capacitors. Before the production of capacitors, analytical calculations and capacitor behaviours in given experiment conditions for the designed capacitor were verified using FEMM 4.2 program. The FEMM 4.2 program has been used to validate the calculated capacitance value of the capacitor. The calculated capacitance value of the capacitor was confirmed by simulation with a deviation of 0.268%. FEMM 4.2 program has been used to make electrostatic analysis. Potential and electric field distribution on the capacitor under experiment conditions were examined by using finite element method simulations. Under the specified test conditions, the level of electrical stress on the capacitor surfaces was examined and the distribution values on the material were found within the appropriate ranges for the experiment.  As a result of the capacity measurements the capacitance value of the capacitor produced with ABS material was measured as 2.349nF. The relative difference between the measured capacitance values and the analytically calculated values of the produced capacitors is reduced to 5%. Measured capacitance values have been used for analytically calculating the equivalent capacitance of capacitors in condition of series and parallel connection. In case of series and parallel connection of capacitors, maximum %1,254 decreasement has been occurred between the measured values and the calculated values. In the electrical stress tests of the discs and the capacitors: the capacitors were tested up to 50 kV under 50 Hz AC voltage. At this level, 2.5 nF capacitors did not experience electrical breakdown. When the current drawn by the capacitors reached 20 Amperes, the experiment was terminated due to insufficient power of the transformer.  Discs made of PLA and ABS material with the same thickness as the insulator surface of the capacitor (1.2 mm thickness and 5 cm diameter) were able to withstand 30 kV in the tests of electrical breakdown in oil. Discs made of PLA and ABS material, 3.2 mm thickness and 5 cm diameter, were able to withstand between 50 kV - 55kV in the tests of electrical breakdown in oil. The results are in table 6.4 (Çizelge 6.4). The experiments were successful. During the electrical breakdown test, voltage was applied to the smooth surface of the discs. Only on two PLA discs' voltage was applied to the rough surface. The disc, which is 3.2 mm, has failed at a voltage level 7.62% lower than the average of other 3.2 PLA discs. The disc, which is 1.2 mm, has failed at a voltage level 19.67% lower than the average of other 1.2 PLA disc. The difference between the capacitance values obtained as a result of the experiments and the values calculated analytically; caused by structural defects in capacitor designs. It has been observed that more efficient results are obtained with the positive increase in the print quality of the produced capacitors. In light of these conclusions, a number of corrections and improvements can be made to the capacitors which has been design based on planar capacitor concept. In order to prevent any electric arc on the surface of the capacitors, it can be said that the design should be produced in a closed manner. In order to place the electrodes in the design of the capacitor, a special area must be added according to the electrode type. This area may be designed to form a pocket outward from the outer wall of the design.  Although some improvements in design and production are required; the objectives of the research were successfully achieved. Thus, the feasibility of an electrical element with three-dimensional printer has been demonstrated. An initiator study was carried out for future studies and innovative ideas. The printing method and material properties of the three-dimensional printers that will be used in future studies can eliminate the negative effects of this research or create new problems and solutions. This process; The capabilities of three-dimensional printers will form the basis of new and untested designs in line with the knowledge and imagination of researchers from different disciplines. In the first part of the study, the development of capacitors from past to present and their usage in high voltage field are examined. In the second part, physics rules that form the working principles of capacitors and their equations are examined. In the third part, the information about the insulating materials used in their designations which make up the design differences in capacitors are given. In the fourth chapter, Information is given about FDM three-dimensional printers, the materials used by the printers and the usage areas of the printers. In the fifth chapter, the analytical calculations of the designs and the electrostatic field analyzes calculated using the finite element method are given. In the sixth chapter, the experiments of the capacitors and material test samples produced with three-dimensional printer are given. In the seventh chapter, problems encountered during the study, possible solutions, interpretation of test results and suggestions are given.