July 4th

Extreme possibilities of circuital models of electrical machines

The paper presents possibilities of so-called circuital mathematical models of electric machines, in which the machine is treated as a set of magnetically coupled coils. It is a very popular class of models used for analysis of operational conditions of electric machines. However, the progress in numerical solutions of electromagnetic filed causes the interest of researchers to shift into so-called field-models.

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July 3rd

Rotor power loss in a PM SM by calculation, simulation and measurements, mutual verification of methods

The subject of the paper is the comparison of four complementary methods of the rotor loss estimation in a PM SM, supplied by a PWM voltage source. An ANSYS based finite element model produces values of W, the magnetic energy stored, and P, the rotor losses. On analytical level the machine is represented by a parallel two elements equivalent circuit for each voltage harmonic. Its parameters are estimated using P and W values.

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July 2nd

Additional losses by magnetic field harmonics in the rotor bars of asynchronous machines and their influence

Optimizing the efficiency of modern asynchronous machines requires the knowledge of the particular loss components. In this contribution a method shall be presented, where by the transient FEM-calculation the copper losses in the rotor bars by harmonic field effects and the consequential originating harmonic currents can be estimated. By this way the determination of the current density of the rotor current harmonics is carried out along the height of the rotor bar.

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July 1st

Electromagnetically excited audible noise - evaluation and optimisation of electrical machines by numerical simulation

Disturbing vibrations and noise of electrical machines are gaining impact. Therefore, it is necessary to estimate the electromagnetic, structure-dynamical, and acoustic behavior of the machine during designing and before prototyping. An adequate tool is numerical simulation applying the Finite-Element Method (FEM) and the Boundary-Element Method (BEM) allowing for the structured analysis and evaluation of audible noise also caused by manufacturing tolerances.

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