Robust uncertainty modelling of energy variations in electric motors for efficient and reliable mechanical structural analysis

Year 2018, Volume: 5 Issue: 1, 9 - 12, 05.04.2018

Murat Mayda

https://doi.org/10.31593/ijeat.400164

Abstract

The mechanical power and rotational speed of
electric motors have significantly uncertainties arising from energy variations
such as the magnetic energy, the flux linkage variation of the winding, and the
air gap due to the rotor position. The main aim of this work is to address the
effect of the uncertain output power and rotational speed of an electric motor
on mechanical structural analysis, especially on the torsional analysis, and
accordingly to model the statistical characteristics of variations in torque of
the motors in consideration of different powers and speeds for further
efficient and reliable mechanical structural analysis under uncertainty. To
perform these tasks, a case study that is the torsional loading of a shaft by
an electric motor and generator, is carried out. The results show that the
uncertainty of power and speed in electric motors considerably affects the
probability of failure of the shaft in case of exceeding the maximum shear
stress, and increasing the speed at a given power does not significantly change
the COV value of the torque whereas increasing the power at a given speed can
relatively change the COV value of the torque. The obtained average of the COV
values (0.0023) of torque with normal distribution is fairly sufficient for
indicating the variations in the torque of electric motors. Moreover, the
obtained torque uncertainty can be easily and efficiently used in the
mechanical structural analysis under both deterministic and stochastic cases.

Keywords

Electric motors, energy variations, uncertainty, modelling, structural analysis

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