Webinar on electromagnetic NVH issues in electrical machines

EOMYS has added a third date for its webinar on NVH issues on electrical machines. The updated dates are:

• Wednesday 15th February at 10.30 AM (CET - UTC+1)
• Wednesday 22nd February at 9 AM (CET - UTC+1)
• Thursday 23rd February at 5 PM (CET - UTC+1)

The webinar is organized in two parts:
I. Magnetic noise and vibrations phenomena

• What is magnetic noise and vibrations?
• Principle of resonance due to Maxwell forces
• Noise reduction techniques at design stage (e.g. skewing, slot/pole combinations, current injection)

II. MANATEE electromagnetic & vibroacoustic software

• Simulation models
• Case study of an induction machine for traction application

The webinar lasts 45 minutes including 15 minutes to answer technical questions at the end. To attend the webinar, don’t forget to register on our website.

Zoom on MANATEE features

Harmonic decimation tool

To analyze the root cause of noise, vibration or torque ripple harmonics, MANATEE offers a powerful tool called the Harmonic decimation tool.
This tool allows to cancel a specific set of harmonics at different stages of the simulation workflow: on airgap permeance, rotor or stator magnetomotive force, radial or tangential airgap flux density.
Let’s take the example of the surface permanent magnet synchronous machine of the tutorial. The cogging torque waveform can be obtained by the command plot_torque_Maxwell:

Cogging torque as a function of time

As expected, the largest component is at 900 Hz and corresponds to LCM(Zs, 2p) times the mechanical frequency. The decomposition of the interaction of the flux density waves creating the cogging torque can be analyzed using the space vector graph of tangential magnetic forces plot_Ft_vectors.

Tangential magnetic force FFT2 vector diagram

By clicking on the wavenumber r=0 at 900 Hz (first harmonic of cogging torque), one can see that this component results from constructive and destructive interferences of different flux density waves of wavenumbers 34, 38 and 22, 26. According to theory, the main contributors are indeed the magnetomotive force wavenumbers LCM(Zs,2p)+/-p (34 and 38).
The wavenumbers 22, 26, 34 and 38 can be observed in the FFT of the flux density obtained with plot_B_space:

Radial and Tangential Airgap Flux

These specific harmonics can be artificially cancelled using the harmonic decimation tool, using either the GUI or command lines. The new flux density and the new cogging torque waveform are then:

Effect of the Harmonic decimation tool on the flux

Effect of the Harmonic decimation tool on the cogging torque

MANATEE coupling with Simulink®

MANATEE can be coupled to a Matlab Simulink® model for the generation of voltage waveforms at a given speed.

Recent development for the next MANATEE release

• A new slot type 29 has been implemented.
• Possibility to analyze the harmonic content of magnetic forces in command line, for instance with find_harmonic_PMSM_open_circuit.
• Possibility to plot the Frequency Response Function with the new plot_FRF command.

Publication of the Month

In this new section of the Newsletter, EOMYS will feature every month a new publication from the EOMYS Team or a recent paper that we wanted to share.

EOMYS has submitted to the International Electric Machines & Drives Conference 2017 a paper presenting a methodology to extend the subdomain modeling techniques to interior permanent magnet synchronous machines.

The principle is to use MANATEE to FEMM automated coupling to calculate the rotor magnetomotive force of a single pole (including saturation of bridges) and use this information to deduce the magnetization characteristics of an equivalent surface magnet. This way, the optimized subdomain model of SPMSM which includes slotting effects, permanent magnet field and armature field for any winding type can be reused for the fast calculation of IPMSM airgap flux density.

To keep track with our latest publications, you can follow Jean Le Besnerais’ page on Researchgate.

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