Two Excitation Methods To Assess The Vibrational Behaviour Of The Switched Reluctance Motor (SRM)

Switched Reluctance Motors (SRMs) are increasingly expected to become the technologydriving tomorrow’s electric vehicles. However, a key challenge remains: troublesome acousticnoise. In fact, unwanted torque ripples cause, at certain operation speeds, modal deformationsof the SRM stator, resulting in noise generation. The objective of the present work is to ensurea reliable measurement procedure to assess the stator structural dynamics.In this view, an extensive literature investigation was carried out. The structure andoperating ways of SRMs were clarified together with some useful basics of structuraldynamics and acoustic theory. Thereby, the chain reaction of troublesome noise generation inSRM was overviewed, starting from the origin of torque ripples and concluding with thepropagation of acoustic waves. In the meantime, a particular care was paid to defining themodal analysis parameters involved and relevant results from previous studies were gathered.Then, the experimental investigation consisted in the structural testing of a given SRMby means of two testing methods. Indeed, Impulse Hammer and Miniature-Shaker Spectraltests were implemented. A substantial number of accelerometers were installed on the statorto accurately measure a wide range of mode shapes. For both testing methods, measurementcoherence, power spectral density and transfer paths reciprocity were continuously assessed.After that reliable frequency ranges were determined, the modal analysis of the collected datawas carried out. If applicable, the determined modal parameters were validated applyingAutoMAC criterion and comparing the synthetized FRFs to the original ones.Finally, the outcome of the investigation consisted in clear mapping of the modalbehaviour of the given SRM stator around its most critical modes. Indeed, the spectrumstarting from0.5kHz and reaching2.3kHz was measured. These results were discusses themin light of the literature review with particular attention paid to DOS SANTOS et al.(2012)results. Both testing methods were compared and some perspectives for further fieldinvestigation were given. The final outcome is to provide new insights for designers willing todevelop the next generations of SRMs.