Analysis of a permanent magnet synchronous machine with regard to explosion protection capability

 

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N. Yogal

Analysis of a permanent magnet synchronous machine with regard to explosion protection capability

ISBN: 978-3-95606-461-6   |   Erscheinungsjahr: 2019    |    Auflage: 1
Seitenzahl: 248   |    Einband: Broschur    |    Gewicht: 745 g
Lieferzeit: 2-3 Tage
25,00 €
Inkl. 7% MwSt., zzgl. Versandkosten bei Auslandsbestellungen

Permanent magnet synchronous machines (PMSMs) are used because of their superior advantages regarding energy efficiency and controllability in industrial applications, very highspeed drives, aerospace applications and electrical vehicles e.g. in the automotive industry. The use and demand of these machines are increasing in hazardous areas like mining, chemical and petrochemical industries as well. In an explosive atmosphere, these electric machines must be operated with their maximum surface temperature below the ignition temperature of the surrounding explosive environment. Proper investigations during the design, manufacturing, and operation of machines should be considered in order to minimize the possibility of an explosion. An explosion proof electric machine should satisfy safety and failure performance, explosion-proof performance, as well as low noise and vibration requirements at normal and failure operation. The magnetic properties of permanent magnet (PM) materials and non-oriented (NO) electrical steel sheets materials that are used in the rotor and stator yoke manufacturing greatly influence the working performance of PMSM. Similarly, these materials are enormously affected by temperature and frequency. Temperatures that exceed the specification may results in irreversible demagnetization of PM while higher frequency result in higher iron losses of NO electrical steel sheets. Demagnetization and higher iron losses increase the temperature of the PM and core respectively which may result in the hot spots of the machine and could be the source of ignition. Therefore, proper study and understanding of magnetic properties of such materials are required. These help engineers, machines manufacturers and designers in designing robust machines with high tolerance to explosive environment. Investigation of PM is carried out using thermal endurance and corrosion tests. The non-oriented electrical steel sheets are measured using ring core specimens test methods. The outcomes of these tests are compared to the simulated (finite element method) results using the Opera 2D simulation software. This work focuses on safe operation of PMSMs, as it undergoes through a series of mechanical, electrical and thermal tests. These tests methods ensure that no hot surfaces, electrical arcs or sparks occur during normal operation or there are no possible failure conditions in all inner and outer parts of the machines that can lead to high energy, responsible for ignition. The PMSM installed in hazardous areas need to have protection against possibility of ignition. Therefore, the thermal protection of the PMSM using PTC thermistors sensors are tested so that the PMSM stops operating in case of higher thermal heating of stator winding. Different influencing input quantities from the instruments used for measurement in the test bench are studied and the uncertainty is analysed. While determining the efficiency of the machines the final measurement uncertainty of the test bench is examined and presented with "Guide to the Expression of Uncertainty in Measurement" (GUM) procedure. Besides the testing of the PMSM this work therefore deals mainly with problems concerning the demagnetization of the PM during abnormal operating condition of PMSM using simulation. Finally, the practicable testing procedures for PMSMs is developed. The "test rule" briefly described the requirements, testing (mechanical, electrical and thermal) and installation conditions for VSDs fed rotating PMSMs of the type of protection “Increased Safety” ignition protection classification. It is analogous to the test rule for explosion-proof asynchronous machines. In addition, the development of manufacturer-independent "certification rules" for the explosion-proof PMSMs is included. The results obtained from this work are accumulated and will probably be integrated in future explosion proof standards IEC 60079-X. Keywords: Corrosion, Demagnetization, Eddy currents, Electrical steel sheets, Energy efficiency, Explosion protection, Finite element analysis, Fourier transforms, Frequency measurement, Hazardous areas, Loss measurement, Magnetic losses, Magnetic materials, Magnetic properties, Measurement uncertainty, Permanent magnets, Permanent magnet machines, Soft magnetic materials, Switching frequency, Temperature dependence, Thermal effects, Thermistors, Variable speed drives.

PTB Ex-15