Variable-speed open circuit vibro-acoustic simulation with subdomain model

Tutorial summary
Project name tuto_IPMSM_12
Machine name machine_IPMSM_A
Source project tuto_IPMSM_01
Description This project aims at improving the calculation of the airgap flux and resulting Maxwell stress by including the tangential flux density component in the electromagnetic model. This can be done using the powerful subdomain modeling techniques extended to interior permanent magnetic machines as shown in the article "E. Devillers, J. Le Besnerais, M. Hecquet and J-P. Lecointe, A new hybrid method for the computation of electromagnetic noise in open circuit IPM machine, EVER 2017".

The project tuto_IPMSM_01_test is copied/pasted (or loaded and saved with the GUI) in a new project tuto_IPMSM_12_test will the following change:

130. Electromagnetic group (Method panel)
Electromagnetic group (Method panel)
Input.Simu.type_Bmodel=1;

To let MANATEE calculate the optimal number of harmonics in the subdomain model one should also put (available only in the script for now)

Input.Simu.Nhag = 0;                % number airgap space harmonics in subdomain models
Input.Simu.Nhss = 0;                % number stator slot harmonics in subdomain models  
Input.Simu.Nhrs = 0;                % number rotor slot harmonics in subdomain models  
Input.Simu.Nhso = 0;                % number stator slot opening harmonics in subdomain models  
Input.Simu.Nhro = 0;                % number rotor slot opening harmonics in subdomain models  

One can also automatically add the following post processing commands:

130. Pre/Post group
Pre/Post group
Input.Simu.SS_post_filename ='plot_init;plot_B_space;plot_VS_ASWL_modal_cont;plot_VS_ASWL_order_analysis;plot_VS_ASPL_sonagram';

The simulation is run in command line with

run_MANATEE('tuto_IPMSM_12_test')

The call to FEMM is very short and does not significantly change the overall computing time:

FEMM model
FEMM model

The noise as a function of speed is now given by (plot_VS_ASWL_modal_cont) :

Structural mode contribution to A-weighted SWL
Structural mode contribution to A-weighted SWL

The variable speed sound pressure level is given by plot_VS_ASPL_sonagram:

A-weighted sound pressure level sonagram at 1 m
A-weighted sound pressure level sonagram at 1 m

These conclusions show that at no-load up to 6500 rpm, the Prius electrical machine acoustic noise shows two resonances at 12th and 24th the electrical frequency with the breathing mode of the stack. This is in full agreement with the conclusions of this FEA work:

Conclusion of "Electromagnetic and vibrational characteristic of IPM over full torque-speed range"
Conclusion of "Electromagnetic and vibrational characteristic of IPM over full torque-speed range"

Running a full electromagnetic and structural finite element model at variable speed requires several hours of calculation, while MANATEE only takes a few seconds to obtain the same conclusions.

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