Modal characterization of a PMSM using different experimental techniques

In this paper different modal techniques are adopted in order to characterize the vibro-acoustic behaviour of a Permant Magnet Synchronous Motor (PMSM) for automotive applications. In addition to a well-known Experimental Modal Analysis (EMA), the vibration response measurement during ramp (run-up test) is exploited to apply an Operating Deflection Shapes (ODS) and an Operational Modal Analysis (OMA). Specifically, since the electric motor response is characterized by many time orders an Order Base Modal Analysis (OBMA) is adopted to overcome the weaknesses of an OMA, such as”end-of-order” distortions. Pros and cons of each individual technique on the specific application of an electric motor are analysed and discussed. The complementary use of the presented methodologies provides a comprehensive modal analysis of the electric motor.