Skew pattern optimization

Description

Manatee software allows to calculate the effect of skewing on the electromagnetic noise and vibrations levels. A predefined rotor skew pattern can be chosen (e.g. V-shape step skew for IPMSM, linear skew) as well as a user-defined geometry.

Manatee automatically expands electromagnetic calculations and force calculations along the machine axis. Skewing calculations can be quickly performed when using a pre-calculated Magnetic Look Up Table. Skewing is also supported  when importing the airgap flux from a third party software.

Application

This feature allows electrical engineers and mechanical engineers to find the optimal skew pattern maximizing average torque and minimizing noise level along torque-speed curve, while keeping torque ripple and cogging torque to an acceptable level (note: cogging torque and peak to peak torque ripple are in the general case not correlated to e-NVH).

Starting from a reference design, the only required input is the skewing type to be investigated. Manatee automatically defines a parameter sweep on the skew angle and tracks useful information for each design like average torque, peak to peak torque ripple, maximum sound power level over speed and the amplitude of the main noise and forces harmonics.

Skewing can excite longitudinal modes of the electrical machine structure (e.g. mode (2,1) of the stator). It is therefore advised to use it in combination with a realistic 3D FEA mechanical model using modal basis import feature.

Demonstration

Gallery

See also