EPE Association: NORpie 2002 - Topic 06: ELECTRICAL MACHINES

NORpie 2002 - Topic 06: ELECTRICAL MACHINES
You are here: EPE Documents > 05 - EPE Supported Conference Proceedings > NORpie - Proceedings > NORpie 2002 > NORpie 2002 - Topic 06: ELECTRICAL MACHINES

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   Torque Pulsations of Induction Motor
By P. Salminen; J. Pyrhönen [View]
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Abstract: A study of different calculation and simulation methods for analysis of torque pulsation in induction machines is presented. the waveform of the supply voltage has an effect on the induction motor's tendency of producing torque ripple. There exist also torque harmonics, which are generated due to the structure of the machine. The surfaces of the rotor and stator are not smooth, because of the slots. the windings are also distributed non-uniformly and therefore the air-gap flux density is not at all sinusoidal. Not only the supply and the motor produce oscillation to the shaft torque but also the connect ed load in the specific application. the aim is to solve the harmonic content of the motor shaft torque. Simulation models are created with Matlab / Simulink and Cedrat's Flux2D, FEM. Comparison of the harmonic content of the torque is presented for different cases: Matlab simulation models including the winding harmonics and slotting harmonics of stator and rotor, Flux2D finite element method solution and measurement results of a 4 kW induction machine.

   Modelling of Permanent-Magnet Synchronous Machines with Non-Sinusoidal Flux Linkage
By O. Wallmark [View]
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Abstract: In this paper, a model of the permanent-magnet synchronous machine is derived including the effects of a non-sinusoidal flux density distribution, produced by the permanent magnets on the rotor. The intention of the derivation is to yield a framework model, suitable to add additional phenomena, by other researchers. It is shown that the non-sinusoidal flux density will produce current ripple which may affect the performance of various rotor-position estimation algorithms. The current ripple is demonstrated through measurements on an existing machine.

   Circumferential Flux as a Source of Bearing Current of Converter-Fed AC Machines
By P. Mäki-Ontto; J. Luomi [View]
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Abstract: A high-frequency common-mode current occurs in AC motors fed from frequency converters because of the very short rise time of inverter voltage pulses. The capacitive current causes electric and magnetic fields inside the stator iron core, possibly inducing a circulating-type bearing current. In this paper, the circumferential magnetic flux is investigated by means of finite element analysis and experiments.

   Short Circuit Fault Conditions of a Buried PMSM Investigated with FEM
By P. Thelin [View]
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Abstract: This paper investigates four different short circuit fault conditions which can occur for an inverter-fed permanent magnet synchronous motor (PMSM) with buried magnets. The fault conditions are investigated by using fixed-speed time-stepping 2D-FEM calculations. The objectives of the FEM calculations are to estimate the magnitudes of the currents and torques, and to see if there is a risk of irreveribly demagnetizing the permanent magnets.

   Reduction of Torque Pulsations in Axial Flux Interior PM Synchronous Machines
By A. Parviainen; M. Niemelä; J. Pyrhönen [View]
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Abstract: Axial flux permanent magnet (AFPM) machines are found to be an alternative solution for radial flux machines in particular direct drive industrial applications. In such an application one important design objective of the electrical machine is to assure that the torque, produced by the machine, is smooth. A smooth torque reduces harmful mechanical vibrations and it also degreases noise produced by the electromechanical system. This paper reviews methods used in minimisation of torque ripple for the point of machine design. In the end, it is presented a torque ripple analysis of axial flux interior permanent magnet synchronous motor with sinusoidally shaped magnets. the results show that such a design reduces effectively torque pulsations.

NORpie 2002 - Topic 06: ELECTRICAL MACHINES
You are here: EPE Documents > 05 - EPE Supported Conference Proceedings > NORpie - Proceedings > NORpie 2002 > NORpie 2002 - Topic 06: ELECTRICAL MACHINES
	[return to parent folder]

	Torque Pulsations of Induction Motor By P. Salminen; J. Pyrhönen	[View] [Download]
Abstract: A study of different calculation and simulation methods for analysis of torque pulsation in induction machines is presented. the waveform of the supply voltage has an effect on the induction motor's tendency of producing torque ripple. There exist also torque harmonics, which are generated due to the structure of the machine. The surfaces of the rotor and stator are not smooth, because of the slots. the windings are also distributed non-uniformly and therefore the air-gap flux density is not at all sinusoidal. Not only the supply and the motor produce oscillation to the shaft torque but also the connect ed load in the specific application. the aim is to solve the harmonic content of the motor shaft torque. Simulation models are created with Matlab / Simulink and Cedrat's Flux2D, FEM. Comparison of the harmonic content of the torque is presented for different cases: Matlab simulation models including the winding harmonics and slotting harmonics of stator and rotor, Flux2D finite element method solution and measurement results of a 4 kW induction machine.

	Modelling of Permanent-Magnet Synchronous Machines with Non-Sinusoidal Flux Linkage By O. Wallmark	[View] [Download]
Abstract: In this paper, a model of the permanent-magnet synchronous machine is derived including the effects of a non-sinusoidal flux density distribution, produced by the permanent magnets on the rotor. The intention of the derivation is to yield a framework model, suitable to add additional phenomena, by other researchers. It is shown that the non-sinusoidal flux density will produce current ripple which may affect the performance of various rotor-position estimation algorithms. The current ripple is demonstrated through measurements on an existing machine.

	Circumferential Flux as a Source of Bearing Current of Converter-Fed AC Machines By P. Mäki-Ontto; J. Luomi	[View] [Download]
Abstract: A high-frequency common-mode current occurs in AC motors fed from frequency converters because of the very short rise time of inverter voltage pulses. The capacitive current causes electric and magnetic fields inside the stator iron core, possibly inducing a circulating-type bearing current. In this paper, the circumferential magnetic flux is investigated by means of finite element analysis and experiments.

	Short Circuit Fault Conditions of a Buried PMSM Investigated with FEM By P. Thelin	[View] [Download]
Abstract: This paper investigates four different short circuit fault conditions which can occur for an inverter-fed permanent magnet synchronous motor (PMSM) with buried magnets. The fault conditions are investigated by using fixed-speed time-stepping 2D-FEM calculations. The objectives of the FEM calculations are to estimate the magnitudes of the currents and torques, and to see if there is a risk of irreveribly demagnetizing the permanent magnets.

	Reduction of Torque Pulsations in Axial Flux Interior PM Synchronous Machines By A. Parviainen; M. Niemelä; J. Pyrhönen	[View] [Download]
Abstract: Axial flux permanent magnet (AFPM) machines are found to be an alternative solution for radial flux machines in particular direct drive industrial applications. In such an application one important design objective of the electrical machine is to assure that the torque, produced by the machine, is smooth. A smooth torque reduces harmful mechanical vibrations and it also degreases noise produced by the electromechanical system. This paper reviews methods used in minimisation of torque ripple for the point of machine design. In the end, it is presented a torque ripple analysis of axial flux interior permanent magnet synchronous motor with sinusoidally shaped magnets. the results show that such a design reduces effectively torque pulsations.