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 and AVAS options are not activated.

Sound file and spectrograms

Sound of Renault^® Zoe electric powertrain during run-up at maximum torque

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Sound pressure level spectrogram of Renault® Zoe 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 Renault Zoe EV. High pitch, whining noise with increasing frequency is due to pole/slot electromagnetic excitations. Higher frequency sound occuring around 10 kHz is due to PWM effects with asynchronous switching frequency. Some resonances can be visible in the spectrogram near 4.8 and 5.2 kHz which corresponds to the match between electromagnetic forces wavenumbers r=0 and r=GCD(Zs,2p)=4 with circumferential stator modes 0 and 4. As seen in most EV HEV NVH studies, stator breathing mode is responsible for high-pitch airborne noise.

For a more detailed analysis, EOMYS provides technical trainings dedicated to EV HEV NVH.

Application to MANATEE

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