Publication: Kafesli asenkron makinalarda zaman harmonik etkilerinin oluk tasarımı ile azaltılmasına katkılar
Abstract
Bu çalışmada piyasada yaygın olarak kullanılan oluk tiplerinden aynı oluk yüksekliğinde, aynı kesitte değişik rotor oluk tasarımlarının zaman harmonikleri üzerine etkisi incelenmiştir. Amaç; besleme kaynağı tarafından üretilen harmoniklerin devre parametreleri ile ilişkisini ortaya çıkarmak ve zaman harmoniklerinin etkisini azaltmaktır. Asenkron motor eşdeğer devresinde demir kayıpları, doyma olmayan bölge için alınmış ve kayıpların lineer değiştiği varsayımı yapılarak hesaplar karmaşık durumdan kurtarılmıştır. Bu çalışmada işlem karmaşasını önlemek için demir kayıpları ve dolayısıyla demir direnci ihmal edilmiştir. Besleme gerilimi tam sinüs formunda olmadığı için fonksiyonu harmoniklerine açmak gereklidir. Bunun için Fourier analizi kullanılmıştır. Fourier analizindeki Sv harmonik katsayısı işlem karmaşasından uzak kalmak için, terminallere uygulanan gerilimin efektif değeri olarak alınmış, harmonik gerilimleride bu değere göre hesaplanmıştır. Bu çalışma için TEE A.Ş. ait bir motor referans olarak alınmış, alınan bu motorun boşta, kısa devrede ve tam yükünde testleri İTÜ Elek. Mak. Lab. ve TEE A.Ş.' de yapılmış devre parametreleri deneysel olarak elde edilmiştir. Teorik olarak bulunan sonuçlar, bu deneysel verilerle desteklenmiştir. Microsoft Power Station 4.0 Fortran programlama dili ile asenkron motor zaman harmonik analizi oluşturulmuş, analizler bu program aracılığıyla yapılmıştır. Bunun yanında Fortran ve Oersted simülasyon elde edilen optimal oluk, referans oluk ile karşılaştırılmış sonuçlar ve grafikler tezin sonunda verilmiştir. Elde edilmiş yeni oluk şekli optimize oluk olarak isimlendirilmiş ve sonuçları analiz ve simülasyon verilmiştir. Bu çalışmaların sonucunda zaman harmoniklerinin etkilerini azaltmak mümkün olmuştur. Ancak bu analiz çalışmaları yapılırken motor parametrelerinin değişimine dikkat edilmelidir. Reaktans değişimi ile bakır kayıpları ve dolayısı ile veri parabolik bir eğri çizmektedir. Bu eğrinin maksimum olduğu reaktans değeri, maksimum verimi ve maksimum kayıpları vermektedir.
Induction motors are commonly used in motor industry, because of their cheap costs and easy maintenance. In engineering world , one of the aim is to decrease the losses in machines. Losses are accured in a stator, rotor and in the iron part of the machines. In this study rotor losses have been analysed. When the machine is subjected to a nonsinusoidal voltage waveform. All the parameters of the machine have been calculated by design datas supplied[1,2,5,6]. In this study the casual effects of time harmonics to the induction machine have been determined and neccessary solutions have been obtained by using Fortran Mikrosoft Power Station 4.0 and Oersted Simulation programs. For this reason experimentel studying has been done in İTÜ Electric Machinary Laboratory and TEE A.Ş. At the begining of the study four different slots were taken into consideration, which one of them choosen as reference then nearly 26 different slot combinations have been analysed and optimized by using Fortran Power Station Program. After the completion of this analysis one of them has been selected as the best slot and analysed by Oersted Motor Analysis computer program both Fortran and Oersted were represented in the thesis. Test and the computer programming were performed for a reference slot combination and the compared, satisfactory and expected results were obtained. The design data of the induction machine with the necessary informations such as calculation of the parametres for both stator and the rotor and their slot geometry dimensions were given as a input and all rotor harmonics reactans, resistance, currents, voltage, slip, torque, output power were formulized and obtanined as a output. 26 individual programmes heve been performed finally which was named as a optimized slot was choosen as an optimal slot. New datas were entered to change the previous datas during the process of the Fortran Mikrosoft Power Station 4.0. In the Fortran program, stator parametres were taken into consideration as a constant. Hoıwever to change stator parameters or add the formulations of parametres to program is easy. The geometry has to be drawn, before analysis. Drawing the geometry without errors is a vital study. There are also phsical properties, have to be assigned. In this study current source was used. The important point, entering the value has to be in terms of amper-turns. At the end all these prosesses, were analysed once again. In the next chapter the reference slot is tested and its results have been given. According to this results, optimized rotor slot were constructed and test results were taken into consideration. In the following chapter, all the results obtained were compared in detail. The last part is prepared for suggestions for the future works.
Induction motors are commonly used in motor industry, because of their cheap costs and easy maintenance. In engineering world , one of the aim is to decrease the losses in machines. Losses are accured in a stator, rotor and in the iron part of the machines. In this study rotor losses have been analysed. When the machine is subjected to a nonsinusoidal voltage waveform. All the parameters of the machine have been calculated by design datas supplied[1,2,5,6]. In this study the casual effects of time harmonics to the induction machine have been determined and neccessary solutions have been obtained by using Fortran Mikrosoft Power Station 4.0 and Oersted Simulation programs. For this reason experimentel studying has been done in İTÜ Electric Machinary Laboratory and TEE A.Ş. At the begining of the study four different slots were taken into consideration, which one of them choosen as reference then nearly 26 different slot combinations have been analysed and optimized by using Fortran Power Station Program. After the completion of this analysis one of them has been selected as the best slot and analysed by Oersted Motor Analysis computer program both Fortran and Oersted were represented in the thesis. Test and the computer programming were performed for a reference slot combination and the compared, satisfactory and expected results were obtained. The design data of the induction machine with the necessary informations such as calculation of the parametres for both stator and the rotor and their slot geometry dimensions were given as a input and all rotor harmonics reactans, resistance, currents, voltage, slip, torque, output power were formulized and obtanined as a output. 26 individual programmes heve been performed finally which was named as a optimized slot was choosen as an optimal slot. New datas were entered to change the previous datas during the process of the Fortran Mikrosoft Power Station 4.0. In the Fortran program, stator parametres were taken into consideration as a constant. Hoıwever to change stator parameters or add the formulations of parametres to program is easy. The geometry has to be drawn, before analysis. Drawing the geometry without errors is a vital study. There are also phsical properties, have to be assigned. In this study current source was used. The important point, entering the value has to be in terms of amper-turns. At the end all these prosesses, were analysed once again. In the next chapter the reference slot is tested and its results have been given. According to this results, optimized rotor slot were constructed and test results were taken into consideration. In the following chapter, all the results obtained were compared in detail. The last part is prepared for suggestions for the future works.