NVH analysis of Electric motors for Hybrid and Electric powertrains

Electrification in the automotive market has grown rapidly over the last decade as a result of new government regulations imposed to reduce emissions. This has resulted in an increase in the market share of electric vehicles. With the advancement of this technology, engineers have faced new challenges in the design of new vehicles, one of which is related to NVH and occupant comfort. As a result, considerable effort is being expended to reduce noise and vibration while increasing efficiency in order to achieve better ranges. The main goal of this thesis work is to investigate and comprehend the primary causes of noise and vibration generation in electric machines, as well as the impact of design choices on electric machine losses and noise generation. The first section investigates the effect of two different winding configurations, concentrated and distributed windings with the same rotor geometry, on Sound Pressure Level (SPL) and electric machine losses. The second section of the study focuses on the sensitivity analysis of the NVH and electric machine losses caused by the stator slot opening. Furthermore, the effects of different tooth shapes (flat and with fillet) are investigated. The key performance indicators used to evaluate the best trade-off solution are cogging torque, ripple torque, electric machine losses, and SPL. The analysis is carried out with an Interior Permanent Magnet (IPM) motor, but the proposed methodology is easily adaptable to other topologies. The FEMM code was used to design the electric machines.