Chair of Electrical Machines E-21

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1 Chair of Electrical Machines E-21 SCIENTIFIC AND RESEARCH ACTIVITIES OF CHAIR OF ELECTRICAL MACHINES Scientific and research activities of the Chair of Electrical Machines are associated with the general topic of "Modelling and examining of electrical machines for the purpose of analysing and designing their structure, exploitation patterns and diagnostics". As a part of this general topic, the detailed tasks are undertaken, which can be associated with the following problems: METHODICAL ASPECTS OF MODELLING ELECTRICAL MACHINES AND ASSOCIATED SYSTEMS Together with the development of new methods of power supply and control, the requirements regarding the precision of modelling the electromagnetic phenomena in electric machines increased significantly. So the issue of preparing new methods of developing and solving mathematical models of electric machines in still existing. The works conducted at the Chair of Electrical Machines are of a methodical character and refer to the so called circuital models of electrical machines, using the concentrated parameters (of an integral character). The basis for those works s the theory of electromechanical energy conversion and electromechanical systems, using the formalisms of the analytical mechanics. The specific character of electrical machines and cooperating systems means, that the modification of the existing routes or the development of new routes for formulating the equations for those types of objects and new methods of solving those equations, became necessary. The following publications from the recent years shall be considered to be representative for the afore lines of research: 1. Sobczyk T.J., An improved algorithm for steady-state modelling in AC machines, COMPEL The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, Publisher Emerald, 2010, Vol. 29, Bul.3, pp Sobczyk T. J., Radzik M., Direct Determination of Currents Spectra of Synchronous Machines at Load Perturbations, Proc. of IEEE-SDEMPED 09, IEEE Catalog Number CFP09SDE-CDR, TF Sobczyk T.J.: Frequency analysis of faulty machines possibilities and limitation, Proceedings of SDEMPED 2007, Cracow, , pp , and CD IEEE Catalog No.07EX1706C, paper sf-0035, IEEE Xpolre. 4. Sobczyk T.J.: Extreme possibilities of circuital models of electric machines, Electrical Power Quality and Utilisation, Vol. XII, No. 2, 2006, pp Sobczyk T.J.: Metodyczne aspekty modelowania matematycznego maszyn indukcyjnych, Wydawnictwa Naukowo-Techniczne, Warszawa, Sobczyk T.J.: O pewnej obwodowej reprezentacji magnetycznie sprzęŝonych cewek, Materiały Międzynarodowej Konferencji Seminarium Podstaw Elektrotechniki i Teorii Obwodów, IC- SPETO 2003, Niedzica, , T.2, str Sobczyk T.J., Drozdowski P., Weinreb K.: Modelowanie matematyczne maszyn prądu przemiennego dla potrzeb diagnostyki, Wybrane problemy elektrotechniki i automatyki. Politechnika Krakowska, Nr 4, Kraków 1995, str

2 AN ANALYSIS OF FAILURE STATES AND THE DIAGNOSTICS OF ALTERNATE CURRENT MACHINES This topic is still the main subject of the research conducted by the Chair. Initially, the analyses regarding the failure states in electrical machines and various side effects associated with the regular work of electrical machines prevailed, however gradually, the weight shifted towards the diagnostic tasks, which currently prevail as the research topics. Currently the research is concentrated on issues associated with the monitoring and the diagnostics of the alternate current machines, using the Internet. The majority of the research was directed at detecting eccentricity and damage to the cages and rotors of induction motors, and the range of factors which are analysed is constantly broadened. The subject of the research is the development of the diagnostic patterns with the use of the highly specialised mathematical models of cage induction machines. And the development of the diagnostic algorithms based on the artificial intelligence methods, and in particular the patterns recognition and artificial neural networks. Many advanced signal processing techniques are used as well as the newest information data acquisition and conditioning techniques. This research was, to a significant degree, realised as a part of research projects, financed by the State Committee for Scientific Research (KBN). In the years a research project "Application of image recognition techniques to the diagnostics of electrical current machines, based on measurable currents" ["Zastosowanie technik rozpoznawania obrazów dla diagnostyki maszyn elektrycznych prądu przemiennego bazującej na prądach pomiarowo dostępnych] (8 T10 A ) was realised. In years a research project "Databases for utilisation the artificial intelligence methods in a non-invasive diagnostics of rotors of cage motors" [Bazy danych dla zastosowania metod sztucznej inteligencji w bezinwazyjnej diagnostyce wirników silników klatkowych] (PB 1696/ T10/201/21) was realised, and in years , a research project, financed by the Ministry of Scientific Research and Information Technology "Distributed diagnostic system of large asynchronous motors" [Rozproszony system diagnostyczny silników asynchronicznych duŝych mocy] (3 T10A ) was realised. The research in the field of diagnostics also constituted the basis for the scientific development of the employees of the Chair. In 2005 Maciej Sułowicz, PhD. Eng. obtained a doctors degree after preparing the thesis titled: "Diagnostic of inductance motors with the us of the artificial intelligence methods" [Diagnostyka silników indukcyjnych metodami sztucznej inteligencji] (promoter professor Tadeusz Sobczyk. PhD. DSc. Eng.), realised with financial assistance of the State Committee for Scientific Research as a part of the promoter's project "Diagnostic of induction motors with the use of artificial intelligence" [Diagnostyka silników indukcyjnych metodami sztucznej inteligencji] (4 T10A ). Konrad Weinreb, PhD. Eng. prepared (in Russian) a monograph titled: "Diagnostic of failures of the rotor of asynchronous machine on the basis of analysis of the spectrum of the stator currents" [Diagnostyka uszkodzeń wirnika maszyny asynchronicznej w oparciu o analizę widma prądów stojana]. The results of the research are used in various diagnostic expertises prepared for the industry and the Chair is looking for partners interested in developing specialised systems for diagnosing rotors of induction machines. The diagnostic of rotors of induction machines is the most important offer directed by the Chair to the industry. The following publications from the recent years shall be considered to be representative for the afore lines of research:

3 1. Sułowicz M., Borkowski D., Węgiel T., Weinreb K.: Specialized diagnostic system for induction motors, Przegląd Elektrotechniczny (Electrical Review), R. 86. No. 4/ 2010, pp Węgiel T., Weinreb K., Sułowicz M.: Main inductances of induction motor for diagnostically specialized mathematical models, Archives of Electrical Engineering, ISSN , Volume 59, Number 1-2 / SEPTEMBER 2010,str Weinreb K., Sułowicz M.: Skuteczne wykrywanie ekscentryczności dynamicznej w silniku asynchronicznym, Zeszyty Problemowe BOBRME Katowice, Nr 83/2009, str T.J. Sobczyk, W. Maciołek, On Uniqueness of Diagnosis of Induction Motor Cage Faults, Przegląd Elektrotechniczny, Pub. Sigma-NOT, vol. 85, No.1, pp , Jan Вейнреб К.: Обнаружение динамического эксцентриситета и обрыва стержней клетки в асинхронном двигателе методом спектрального анализа тока статора, Научнотехнические ведомости СПбГПУ - Основной выпуск, 1(53)2008, C Weinreb K., Sułowicz M.: Nieinwazyjna diagnostyka wewnętrznych niesymetrii uzwojeń maszyny synchronicznej, Zeszyty Problemowe BOBRME Katowice, Nr 77/2007, str Węgiel T., Sułowicz M., Borkowski D.: Centrum diagnostyczne do zdalnej oceny stanu silników indukcyjnych, Zeszyty Problemowe BOBRME Katowice, 2007, nr 77, str Wegiel T., Sułowicz M., Borkowski D.: A Distributed System of Signal Acquisition for Induction Motors Diagnostic, Proceedings of SDEMPED 2007, Cracow, , pp , and CD paper sf-0021, IEEE Xpolre. 9. Sobczyk T.J., Węgiel T., Sułowicz M., Warzecha A., Weinreb K.: Slot harmonics in cage motors due to saturation of a main magnetic circuit, Compel, Vo.25, No.1, 2006, Emerald, pp Weinreb K., Węgiel T., Sułowicz M.: Wpływ wewnętrznych niesymetrii w silniku asynchronicznym klatkowym na własności widma prądu stojana, Przegląd Elektrotechniczny, Nr 11/2006, str Sobczyk T.J., Węgiel T., Sułowicz M., Warzecha A., Weinreb K.: A distributed system for diagnostics of induction motors, Proc. of IEEE SDEMPED 2005, Vienna, , pp Sobczyk T.J., Maciołek W.: Does the component (1-2s)fo in stator currents is sufficient for detection of rotor cage faults?, Proc. of IEEE SDEMPED 2005, Vienna, , pp Sobczyk T.J., Maciołek W.: Asymmetry factors of rotor cage, Czasopismo Techniczne, Wyd. Politechniki Krakowskiej, Vol.102, Z.5-E/2005, pp Warzecha A., Węgiel T., Weinreb K., Sułowicz M.: Non-linear permeance function of magnetic circuit in asynchronous motor with rotor eccentricity, Czasopismo Techniczne 5E/ Wydawnictwo Politechniki Krakowskiej, str Węgiel T., Weinreb K., Warzecha A., Sułowicz M.: Model of cage induction motor with saturated main magnetic circuit for diagnostics applications; Czasopismo Techniczne 5E/ Wydawnictwo Politechniki Krakowskiej, str MODELLING MAGNETIC NONLINEARITY IN ELECTRIC MACHINES USING THE CIRCUITAL APPROACH The research in this field is conducted parallel to other subjects. The problem of modelling magnetic nonlinearity is one of the most difficult ones in the entire field of electric machines

4 analyses and it is still a matter of interest of various research centres. In our Chair, this problem is researched by Professor Tadeusz Sobczyk, PhD, DSc, Eng, and Adam Warzecha, PhD, Eng. The key problem is the qualitative and quantitative determination of nonlinear characteristics of windings of electric machines, as the correct modelling and approximation of those windings is the condition precedent for modelling the magnetic nonlinearity. This research was in the years financed by the State Committee for Scientific Research as a part of the research program: "Nonlinear characteristics of magnetising process of alternate current electric machines" [Nieliniowe charakterystyki magnesowania maszyn elektrycznych prądu zmiennego] (0300/P4/93/04). Research is also conducted on the so called energetic approach to modelling nonlinearity in the machines. It was based on the utilisation of the properties of the co-energy function for the alternate current machines with nonlinear magnetic circuit, and next on the application of the Lagrange formalism for formulating equations, taking into consideration the nonlinearity of the magnetic circuit of the machines. As a result, a significant modification of the general equations is obtained, which assume a standardized form for both the linear and the nonlinear magnetic circuit. Those are the equations of the concentrated constants, using nonlinear, dynamic and static inductances, which are approximated by the multidimensional, correlated functions of the currents and the mechanical coordinate. The practical simplification of the approximation functions are obtained as a result of the decomposition of the global magnetic field. The parameters of those functions are determined on the basis of the calculations of the filed distribution in the magnetic circuit of the machine. The conducted research showed that the precision of modelling of electrical machines, with the use of the so formulated models is comparable to modelling with the use of the field circuital approach, providing the massive conductors and the phenomenon of the magnetic hysteresis are not taken into account. The following publications from the recent years shall be considered to be representative for the afore lines of research: 1. Warzecha A., Wielowymiarowe charakterystyki magnesowania w modelach obwodowych maszyn elektrycznych, Wydawnictwo Politechniki Krakowskiej, Monografia nr 381, Kraków, (przyjęte do druku). 2. Sobczyk T.J., Application of higher order forms for description of electromechanical energy converters, Proc. of EPNC, 2010, pp Sobczyk T. J., Inductanceless model of salient-pole synchronous machines, Proceedings of Int. Symposium on Power Electronics, Electrical Drives, Automation & Motion (SPEEDAM 2008), Ischia, , paper MEM 193, IEEE Explore. 4. Sobczyk T.J., Węgiel T., Sułowicz M., Warzecha A., Weinreb K.: Slot harmonics in cage motors due to saturation of a main magnetic circuit, COMPEL, Vol..25, No.1, 2006, Emerald, pp Warzecha A., Węgiel T., Weinreb K., Sułowicz M., Non-linear permeance function of magnetic circuit in asynchronous motor with rotor eccentricity, Czasopismo Techniczne, seria Elektrotechnika, Wydawnictwo Politechniki Krakowskiej, z.5-e/2005, s Warzecha A., Nieliniowe charakterystyki uzwojeń maszyny synchronicznej z wydatnobiegunowym wirnikiem, Przegląd Elektrotechniczny, Nr 10, rok s Sobczyk T. J.: Properties of the co-energy function for AC machines with non-linear magnetic circuit, Periodica Polytechnica, Ser. El. Eng., TU Budapest, V.45, 2002, No.4, pp Sobczyk T.J.: An Energy-Based Approach to Modelling the Magnetic Non-Linearity in AC Machines, Part I General formulas for the co-energy, linked fluxes and inductances, Archives of Electrical Engineering, PWN, Warszawa, Vol.48, 1999, Bull.1-2, pp

5 9. Sobczyk T.J.: An Energy-Based Approach to Modelling the Magnetic Non-Linearity in AC Machines, Part II - General equations of AC machines accounting for saturation due to the main MMF harmonic, Archives of Electrical Engineering, PWN, Warszawa, Vol. 48, 1999, Bull. 3, pp Warzecha A., The non-linear characteristics of AC machines based on the calculation of magnetic field co-energy, The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, COMPEL, Vol. 17, no 3, MCB University Press, Bradford, 1998, pp Sobczyk T. J., Warzecha A., Alternative approaches to modelling of electrical machines with non-linear magnetic circuit, Archives of Electrical Engineering, Vol. 46, No. 4, Warszawa, 1997, pp Sobczyk T.J.: An energy-based approach to modelling the magnetic non-linearity in AC machines, International Conference on Electrical Machines - ICEM'96, Vigo, 1996, Vol.3, pp Sobczyk T.J.: Formy macierzowe elektromechanicznych przetworników energii z nieliniowym obwodem magnetycznym, Czasopismo Techniczne, Wyd. PK, Vol.93, Z. 7E, 1996, pp MODELLING AND ANALYSING THE PERMANENT MAGNET MACHINES This topic was developed at the Chair since the mid 1990s. The models of permanent magnet machines were developed on the basis of the Lagrange equations, with the use of the modified function of magnetic co-energy. In years this research was partially funded by the State Committee for Scientific Research, as a part of the research / promoters project No: 8 T10 A 014, finalised in form of doctoral thesis prepared by Tomasz Węgiel, PhD. Eng. titled: "Modelling of synchronous machines, activated by permanent magnets" [Modelowanie maszyn synchronicznych wzbudzanych magnesami trwałymi]. The following publications shall be considered to be representative for the afore lines of research: 1. Węgiel T.: Modelowanie niesymetrii uzwojeń dla generatorów synchronicznych wzbudzanych magnesami trwałymi, Zeszyty Problemowe BOBRME Katowice, 2010, nr 87, str Węgiel T.: Modelowanie maszyn synchronicznych z magnesami trwałymi z ekscentrycznością wirnika, Zeszyty Problemowe BOBRME Katowice, 2009, nr 83, str Węgiel T.: Model matematyczny maszyny synchronicznej z magnesami trwałymi dla zastosowań diagnostycznych; PRZEGLĄD ELEKTROTECHNICZNY, ISSN , R. 84 NR 12/2008, str Węgiel T.: Model of permanent magnet synchronous machines for diagnostic purpose; Czasopismo Techniczne z. 1-E/ Wydawnictwo Politechniki Krakowskiej, str Sobczyk T. J.: Problemy modelowania matematycznego prądnic synchronicznych wzbudzanych magnesami trwałymi, Prace Instytutu Elektrotechniki, 2007, Z. 231, pp Pawluk K., Sobczyk T. J.: Wyznaczanie prądów granicznych dla maszyn synchronicznych z magnesami trwałymi umieszczonymi powierzchniowo, Proc. of Int. Conf. SME 2006, Kraków, , pp Sobczyk T. J., Węgiel T.: Investigation of the steady-state performance of a brushless DC motor with permanent magnets, Proc. of Int. Conf. on Elec. Mach., ICEM 98, Istambul, 2-4, Sept., Pub. by Middle East Tech. Univ.,Vol.2, pp

6 STRATEGIES FOR CONTROLLING MATRIX CONVERTERS Modern electromechanical energy conversion systems usually cooperate with power electronic systems, converting the parameters of electrical energy. Matrix converters are the most promising category of such systems. The works on strategies for controlling matrix converters were conducted at the Chair of Electrical Machines for over 20 years. In the 1090s an algorithm for controlling a matrix converter as a frequency converter, ensuring a full symmetry of input and output voltages and currents, was developed and analysed. This research was summarised in form of doctoral thesis of Miquel Watler, PhD. Eng. titled " Investigation of control strategies for the matrix converter", defended in year XXXX at the Faculty of Electrical Engineering of the Silesian University of Technology. The current research is concentrated on the so called "single period" strategy of matrix converter, for which the Institute obtained a patent The method for controlling a matrix converter" [Sposób sterowania przekształtnikiem macierzowym], No: PL The application of a matrix converter as a system converting the energy generated by the high speed, synchronous generator was analysed. This is the subject of the doctoral thesis of Tomasz Sieńko, Msc, Eng. The implementation of the matrix converter as an element regulating power flow in the power supply line was the subject of doctoral thesis of Dariusz Borkowski, PhD, Eng. "Analysis of work of matrix converter, working as a link in the power supply system" [Analiza pracy przekształtnika macierzowego jako łącznika w systemie elektro-energetycznym]. Defended in 2010 at the faculty of Electrical and Computer Engineering of the Cracow University of Technology. The following publications shall be considered to be representative for the afore lines of research: 1. Borkowski D., Sobczyk T.J.: Influence of Commutation Conditions on Steady States in Matrix Converter, Proc. of EPNC (Electromagnetic Phenomena in Nonlinear Circuit), 2010, Dortmund and Essen, str Sobczyk T.J., Borkowski D.: Application of Matrix Converter for Power Flow Control in a Transmission Line. in Proceedings CD of IEEE Power Tech, Lausanne 2007, No Sobczyk T.J., T.Sieńko.: Application of matrix converter as a voltage phase controller in power systems, Proc. of Int. Conf. SPEEDAM 2006, Teormina, Italy, , CD IEEE Catalog No. 06EX1320C- ISBN , Paper S Sieńko T., Sobczyk T.J.: Matrix converter control for applications to multi-phase highspeed generators, Archives of Electrical Engineering, PWN, Warsaw, 2004, Vol.53, No.2, pp Sobczyk T.J.: The matrix converter a universal power electronic unit, Prace Instytutu Elektrotechniki, Warszawa, 2002, Zeszyt 211, str Sobczyk T.J.: Voltage-current equations of power electronic matrix converters in frequency domain, Archives of Electrical Engineering, PWN, Warszawa, Vol. 51, 2002, No.1, pp Sobczyk T., Watler M.: A new control strategy for the matrix converter, Proceedings of International Power Electronics Conference, IPEC-Tokyo 2000, Tokyo, 3-7 April, 2000, Vol. 2, pp Sobczyk T.J.; Control strategy of matrix converters, Proc. of V Conf. on Power Electronics & Applications (EPE'93), Brighton, 1993, Vol.4 (Control in Power Electronics), pp. (93-97).

7 ELECTRICAL ENERGY GENERATION SYSTEMS FOR DISTRIBUTED, LOCAL RENEWABLE ENERGY SOURCES Generation of electrical energy, based on renewable energy sources requires an entire energy generation route to be correctly designed. This applies to both, the generator and often, the electrical power engineering systems, connecting the generator to the grid. In the Chair, a research on such type small power plants, utilising water energy are conducted. In such systems, generators were activated by permanent magnets and were integrated with water turbine, working with variable rotation speed. In recent years, an intensive research was conducted at the Chair on such type generators. Those works are conducted in cooperation with CEDI (Creative Engineering Design and Innovation), seated in Krzeszowice, associated with a Norwegian company Turbinova S.A., specialising in water power engineering. Currently a development program, titled "System for generating electrical energy for small water power plants, equipped with a generator activated by a permanent magnet, working with variable speed" [Układ do wytwarzania energii elektrycznej dla małych elektrowni wodnych z generatorem wzbudzanym magnesami trwałymi pracującym przy zmiennej prędkości obrotowej]. The puirpose of this project is to create a workstation for analysing the innovative solutions for the energy generation route for small, water power plants. The works on the utilisation of high speed generators for mini power plants powered by gas (or biogas) turbines) and with the use of matrix converters to join them to the grid, are also conducted. The following publications shall be considered to be representative for the afore lines of research: 1. Sobczyk T., Mazgaj W., Wegiel T., Szular Z.: Power electronic unit for small water plants with variable speed PM generator, Proc. of XXI Symposium EPNC 2. Sobczyk T.J., Sieńko T., Danilevicz J.B.: A study of asymmetrical regimes in matrix converters for multi-phase high speed generators, Proc. of IEEE Power Tech 2005, St. Petersburg, , CD - ISBN , Paper No Sobczyk T.J., Sieńko T.: Matrix converter for high-speed generators, Proc. of IEEE IEMDC (International Electric Machines and Drives Conference) 2005, San Antonio, , CD - IEEE Catalog 05EX1023C, pp Danilevicz J., Sobczyk T., Kirichenko B., Shtainle L., Kruchinina I., Khozikov J.: High speed electromechanical converter for gas turbine, ICEM 02, Brugge, Belgium, CD.