Impact of measurement- and test parameters on the rpm-sweep test accuracy of e-motors

The electrification of the vehicle industry has led to a significant increase in the demand for innovative vibration testing. The RPM-sweep experiments of e-motors and e-drives are considered to be fundamental, as they provide valuable vibration and durability data for further analysis. The aim is to model the behavior of rotating-dynamic systems throughout their life cycles. However, inaccuracies in the definition of measurement and test parameters can result inaccurate transfer functions, ultimately reducing the accuracy and reliability of the test results. This paper focuses on two critical parameters: frequency resolution and RPM-sweep rate. Both of these parameters have a significant impact on the amplitude response of the system and can lead to substantial distortion of the FRFs. In this study, we characterize these distortions and propose a method to ensure that the error introduced by the chosen frequency resolution and RPM-sweep rate remains below a predefined threshold value. In addition to the theoretical derivation, we demonstrate the application of this method using real measurement data. This research aims to address the challenges associated with NVH testing in the context of the electrification of the vehicle industry, providing a valuable contribution to the development of more accurate and reliable testing methodologies.