Noise of electric vehicle (EV) powertrain - case of Nissan Leaf

Summary of e-NVH sound sample
Application Nissan Leaf®
Electrical machine IPMSM (48 stator slots, 8 poles)
Supply condition Run-up at max torque
Noise sources Electromagnetic, mechanical, aerodynamic
See also Renault Zoe, Tesla X90

Measurement set-up

Noise is measured close to electric powertrain and at driver’s hear. A 3d accelerometer is placed on the stator housing in the middle of the lamination. A run-up is done with maximum torque up to 100 km/h in free field environment. Eco mode is not activated but AVAS is activated.

Sound file and spectrograms

Sound of Nissan<sup>®</sup> Leaf electric powertrain during run-up at maximum torque
Sound of Nissan® Leaf electric powertrain during run-up at maximum torque

Note: these sound files are the property of EOMYS; for authorized use in presentations, website, publications or technical work, please contact us

Sound pressure level spectrogram of Nissan<sup>®</sup> Leaf electric powertrain during run-up at maximum torque close to engine (left) and at drivers's ear (right)
Sound pressure level spectrogram of Nissan® Leaf electric powertrain during run-up at maximum torque close to engine (left) and at drivers’s ear (right)

E-NVH interpretations

This sound file illustrates electromagnetically-excited noise of the electric powertrain of Nissan Leaf EV. High pitch, whining noise with increasing frequency is due to pole/slot electromagnetic excitations. Higher frequency sound occuring around multiples of 5 kHz is due to PWM effects with asynchronous switching frequencies. Some resonances can be visible in the spectrogram near 8 kHz which corresponds to the match between electromagnetic forces of wavenumber 0 and breathing mode natural frequency of the stator lamination housing assembly. One can also notice that the noise at twice the switching frequency reaches a maximum at mid-speed which reflects the evolution of inverter current harmonic magnitude with increasing modulation index. The AVAS alerting system can be audible at low speed around 2kHz.

Application to MANATE

MANATEE software can be used to quickly calculate NVH due to electromagnetic forces both in early design and detailed design phase, including PWM and slotting effects.

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