Modeling and analysis of electromagnetic vibrations in fractional slot PM machines for electric propulsion

NVH analysis is critical for electric machine design and is used, in many applications, to separate a good (quiet) machine design from a bad (noisy) one. In this paper, a method for predicting the noise and vibration of permanent magnet synchronous machines due to electromagnetic forces is presented. Two types of fractional slot PM machines are employed as the study cases. The different skew in these machines is also taken into account. The proposed method is validated experimentally, and can be used to predict the NVH of various IPM machines with different slot/pole number combinations as found in the automotive industry.