Speaker
Description
The European Union is aiming for significant greenhouse gas reductions in aviation by 2050. In the course of this, electrified drive concepts are also becoming increasingly important, resulting in new challenges with regard to the noise emission of electric machines. In order to gain a better understanding of the generation of noise, a coupled drive train consisting of two permanent magnet axial flux machines connected in series was investigated experimentally. The rotational speed and torque as well as the sound pressure level in the free field and surface velocity of the structure were measured at various stationary operating points and run-up scenarios using microphones, triaxial acceleration sensors and the information provided by the inverter. In order to draw conclusions about the excitation sources, spectral maxima of the measured variables are compared with characteristic frequencies from theory. In addition, information from product data sheets, such as the number of pole pairs of the machine, is used as input parameters for this calculation. The method compares the spectra of different load-dependent test setups simulating a multitude of flight scenarios, which, considering the potential sources of the local maxima, may enable the design of low-noise concepts.