Rotor Optimization to Reduce Electric Motor Noise 2023-01-0540
Electric motor is among the main sources of noise and vibration for electrified propulsion systems. This paper focuses on the electric motor rotor NVH optimization, which is identified as a key enabler to reduce the motor whine, and balances other performance such as motor torque and efficiency. First, conventional rotor NVH design technologies such as rotor skew and asymmetric rotor pole-to-pole design are discussed, along with their associated tradeoff including reduced motor torque and additional sideband orders. Next, a special notch feature is proposed on the rotor surface with one notch per pole at every q-axis. A DOE study leads to the optimal notch design which significantly reduces the dominant motor torque ripple order by up to 20 dB, with minimum impact to motor torque or loss. Further design studies are then performed to explore additional d-axis notches which are symmetrically located within the top layer magnet opening angles. Up to 6 dB reduction is achieved at the most dominant motor winding order, with small trade-off for motor peak torque. Lastly, a prototype baseline rotor design without notch and a rotor with optimized NVH notch are built and tested in a motor fixture and an electric drive unit. Measured vibration and sound power data confirm that rotor notch achieves up to 20 dB reduction, and the optimal design is successfully implemented in the electric motors for General Motors Ultium electric drive units.
Citation: He, S., Zhang, P., Muir, M., and Koch, B., "Rotor Optimization to Reduce Electric Motor Noise," SAE Int. J. Adv. & Curr. Prac. in Mobility 6(1):39-47, 2024, https://doi.org/10.4271/2023-01-0540. Download Citation
Author(s):
Song He, Peng Zhang, Michael Muir, Benjamin Koch
Affiliated:
General Motors LLC
Event:
WCX SAE World Congress Experience
e-ISSN:
2641-9645
Also in:
SAE International Journal of Advances and Current Practices in Mobility-V133-99EJ
Related Topics:
Electric motors
Electric drives
Propellers and rotors
SAE MOBILUS
Subscribers can view annotate, and download all of SAE's content.
Learn More »