ANSYS MotorCAD: E-NVH Analysis
Hello everyone, David Giglio here with Ozen Engineering, Inc. In this video, I will show you how to use ANSYS MotorCAD's mechanical module to perform electric and VH analysis. This analysis helps determine the modes that correspond to noise and vibration produced in the motor.
Understanding Motor Vibration
As the rotor rotates, the eight poles pass by the stator teeth, producing oscillatory repulsive and attractive forces. If the frequency of this oscillation matches the natural frequency of the stator structure, resonance will occur. The goal for the designer or operator is to operate the motor at a frequency that does not match any of the natural frequencies.
- Each mode has an associated stiffness and modal mass number.
- As vibration is applied, more mass is involved in the vibration as speed increases.
Setting Up MotorCAD for NVH Calculation
In MotorCAD, after setting up the motor, we are ready to perform the NVH calculation:
- Go to Calculation > ENVH.
- Define the Torque-Speed curve and set the operating points for analysis.
- Click Generate ENVH and Forces.
The mechanical module uses EMAG to calculate forces and determines the peak line current and phase advance required to achieve the requested torque values.
Analyzing Results
Once the calculation results are available, we can explore various plots:
Stiffness vs. Mode Number
As rotor speed increases, the mode number increases, leading to higher deformation of the stator. The structure exhibits spatial periodicity, and the vibration distribution follows this pattern.
- Mode Number 0: Uniform contraction and expansion.
- Mode Number 2: Deformation into an oval shape with symmetry order 2.
- Mode Number 4: Deformation with symmetry order 4.
- Mode Number 8: Deformation with symmetry order 8.
Torque and Harmonic Analysis
- Analyze how torque relates to the electric angle.
- Examine harmonic amplitude and phase angle in relation to the order of the electrical angle.
Structural and Acoustic Analysis
- Examine space order and frequency effects on the electric angle.
- Analyze static displacement and velocity plots.
- Review acoustic spectrograms to determine sound frequency and radiating power at given speeds.
Conclusion
Thank you for watching. Contact us to learn more about our simulation capabilities and request a demonstration of how we can assist with your engineering projects. Ozen Engineering, Inc. is an ANSYS Elite channel partner, providing training, consulting services, and ANSYS software packages.
Thank you very much and take care.
Hello everyone, David Giglio here with Ozen Engineering. In this video, I will show you how to use ANSYS MotorCAD, the mechanical module, to perform e-NVH analysis to determine the modes that correspond to noise and vibration produced in the motor.
As the rotor rotates, the eight poles pass by the stator teeth and produce oscillatory repulsive and attractive forces. If the frequency of this oscillation matches the natural frequency of the motor's structure, resonance will be produced.
The goal for the designer or operator of the motor is to operate the motor at a frequency that does not match any of the natural frequencies. For each mode, there is an associated stiffness and modal mass number.
As the vibration of the motor is applied, the motor is also operated at a frequency that is not matched to the speed of the motor. As the vibrations get stronger with speed, more mass is oscillating, more mass is involved in the vibration.
In MotorCAD, after we set up our motor, we have it ready to perform the NVH calculation. We go to Calculation, ENVH, set operating points, and click Generate ENVH and forces.
The mechanical module will use EMAG to calculate the forces and the mechanical module will calculate the peak line current and phase advance required to obtain the torque values as close as possible to the requested torque.
Once we have the results for this calculation, we can go to ENVH and look at different plots. For example, a plot of stiffness versus mode number shows how the rotor speed increases, and the motor number increases.
The stator is being deformed with a higher mode number, which means that the structure has a spatial periodicity, and the vibration distribution has spatial periodicity.
As the mode number increases, corresponding to increasing rotor speed, the vibrations are stronger, and more mass is involved in the vibration. The maximum increases, and the frequency of rotation relates to the mode number in a non-linear fashion.
We can also look at torque plots, structural displacement, velocity plots, and acoustic spectrograms. Thank you for watching, and contact us to learn about our simulation capability and request a demonstration.
Ozen Engineering Inc is an ANSYS Elite channel partner and provides training to use ANSYS tools, offers consulting services, and sells ANSYS software packages. Thank you very much, and take care.
