Tutorial summary | |
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Project name | tuto_BPMSM_08 |

Machine name | machine_BPMSM_A |

Source project | tuto_BPMSM_06 |

Description | Same as tuto_BPMSM_06 but at partial load |

In this example the no-load project tuto_test_BPMSM_06 is copied pasted in a new project named tuto_test_BPMSM_08 to find the optimal stator skew angle with respect to acoustic noise at partial load, fixed speed. Magnetic forces now involve both the fundamental field due to the magnets and due to the armature field.

The variable speed calculation based on spectrogram synthesization is unactivated with

`Input.Simu.is_spectro_synthesis=0;`

The partial load is activated using

`Input.Simu.I0 = 10;`

Input.Simu.Phi0 = pi/2;

Input.Simu.is_fixed_load_angle =1;

Input.Simu.is_mmfs = 1;

The speed is fixed at the resonance of the lamination breathing mode close to 6000 rpm:

`Input.Simu.N0=6407;`

The single input variable to be varied is the stator skew angle rate, expressed in stator slot pitch, given by

`Input.Simu.names_var={'skew_rates'};`

The skew rate is evenly varied from 0.8 to 1.2 stator slot pitch with 21 different values using

`Input.Simu.types_var=[0]; %continuous variable`

Input.Simu.types_val=[0]; % Value defined by interval

Input.Simu.type_sampling=[0]; % linspace sampling

Input.Simu.bds_contvar={[0.8 1.2]}; %Values between 0.8 and 1.2

Input.Simu.Nval_contvar=[21]; % 21 values

The output variable that is tracked during the sensitivity analysis is the nominal sound power level:

`Input.Simu.names_resp={'LwrA;};`

The default skew shape is linear, it is defined by the machine parameter

`Input.Geometry.type_skew_geoS=0. `

Finally the electromagnetic skewed model based on 7 slices is activated using

`Input.Simu.type_skew = 2; `

Input.Simu.Nskew_slices = 7;

A the end of the calculation, the noise as a function of the skew rate can be plot using plot_MS_all_resp_var

One can see that the optimal skew is slightly above one stator slot pitch.

**This confirms that the skew minimizing electromagneticall-excited acoustic noise and vibration is not necessarily one slot pitch**.

MANATEE simulation software allows to find the best skew value depending on the force waves responsible for NVH and on the load state of the machine.