tailieunhanh - Recent Developments of Electrical Drives - Part 42

Recent Developments of Electrical Drives - Part 42. The book stating the recent developments of electrical drives, can be useful for engineers and researchers investigating and designing electrical and electronic devices as well as for students and young researchers dealing with electrical and electronic engineering, computer sciences (advanced computer modelling, sophisticated control systems with artificial intelligence tools applied, optimal design bye use of classical and genetic algorithms employed), applied mathematics and all the topics where electromagnetic, thermal, mechanical phenomena occur | . Comparison Between Sinusoidal and Trapezoidal Waveforms 411 References 1 . Dubois Review of Electromechanical Conversion in Wind Turbines TU Delft ITS Faculty The Netherlands April 2000. 2 . Dubois H. Polinder . Ferreira Comparison of Generator Topologies for Direct-Drive Wind Turbines Proceedings of the Nordic Countries Power and Industrial Electronics Conference NORPIE Denmark 2000 p. 22-26. 3 . Gieras M. Wing Permanent Magnet Motor Technology 2nd edition Revised and Expanded Marcel Dekker Inc. New York. 4 . Henderson Jr. . Miller Design of Brushless Permanent-Magnet Motors Oxford Magna Physics Publishing and Calderon Press 1994. . EQUIVALENT THERMAL CONDUCTIVITY OF INSULATING MATERIALS FOR HIGH VOLTAGE BARS IN SLOTS OF ELECTRICAL MACHINES . Pereirinha1 2 and Carlos Lemos Antunes1 ISR-Lab. CAD CAE University of Coimbra 3030-290 Coimbra Portugal ppereiri@isr. 2Inst. Sup. Engenharia de Coimbra. Rua Pedro Nunes 3030-199 Coimbra Portugal Abstract. The equivalent thermal conductivity of insulating materials for a high voltage bar in slots of electrical machines is calculated using the finite element method. This allows the use of much coarser meshes with an equivalent thermal conductivity ke without accuracy loss in the hot spot temperature calculation. It is shown the dependency of ke value on the equivalent mesh used. Some considerations are also presented on the heat flux finite element calculation. Introduction One of the major thermal problems in electrical machines is the steady-state hot spot temperatures in the windings which are responsible for its thermal aging and degradation. So it is important to correctly determine those hot spots in the thermal design of the machine. In the thermal finite element FE modeling of electrical machines all the different materials to be crossed by the heat flux should be considered namely the windings insulations. For a bundle of conductors