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 Toyota® Prius hybrid electric powertrain during run-up (full electric mode up to 40 km/h)

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

E-NVH interpretations

This sound file illustrates electromagnetically-excited noise of the electric powertrain of Toyota Prius HEV. High pitch, whining noise with increasing frequency is due to slot/pole interactions. At starting, PWM effects introduce noise at multiples of 1.25 kHz, and at high speed at multiples of 5 kHz, showing that the PWM strategy varies with speed. Some resonances are observed close to 4.8 kHz between pulsating electromagnetic forces of wavenumber r=0 with the breathing mode of the stator lamination (cf our MANATEE tutorial of Prius 2004 machine). 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.