Variable-speed, sinusoidal current-driven, partial-load simulation

Tutorial summary
Project name tuto_BPMSM_04
Machine name machine_BPMSM_A
Source project tuto_BPMSM_03
Description Variable speed simulation at constant current

We have seen in the previous step of the tutorial Fixed-speed sinusoidal current-driven partial load vibro-acoustic simulation with permeance / mmf model that the synthesized sonagram assumes that the current angle is kept constant along the whole speed curve.

It is however possible to run a specific variable speed simulation at constant current while changing the current angle as a function of speed. This can be done in a separate project tuto_BPMSM_04_test by copy/paste (or load/save with the GUI) of tuto_BPMSM_03_test.

The variable speed mode is activated using

Input.Simu.is_varspeed = 1;

The number of speed steps, the min and max speeds are still defined

Input.Simu.N0_min=500;            
Input.Simu.N0_max=7000;        
Input.Simu.Nspeeds=50;

The control law to be applied at variable speed must therefore be speficied. The variation of the current magnitude and current angle with speed is obtained by specifying

Input.Simu.type_control = 8;

To follow the constant torque/speed curve specified in the reference article at 60 Nm, the following points are specified in the machine file BPMSM_48s8p:

Input.Electrical.N0spec = [0 500 1000 1500 2000 2504 3304 4104 4904 5704 7000];           % rotation speed [rpm]
Idspec=[50 40 30 15 0 -30 -57 -77 -97 -115 -150];
Iqspec=[110 100 85 75 50 39 30 26.4 23.6 23.8 20];

% RMS phase current [A]
Input.Electrical.I0spec = sqrt(Idspec.^2+Iqspec.^2);      
% electrical angle [rad]            
Input.Electrical.Phi0spec = mod(atan(Iqspec./Idspec),pi);                              

In the GUI, all these parameters are in Workflow:

150. Workflow group (Variable speed tab)
Workflow group (Variable speed tab)

You can also preview the control that you entered:

150. Control law preview
Control law preview

The obtained sound pressure level can still be obtained with plot_VS_ASPL_overall

140. A-weighted variable speed sound pressure level
A-weighted variable speed sound pressure level

One can see that the resonances close to 3000 and 6000 rpm present at no-load are still here, but the magnitude of the maximum levels are different: this is because some destructive or constructive interference occur between armature-induced force harmonics and magnet-induced force harmonics.

The valued of id and iq currents can be checked after the calculation using plot_VS_var(’Id0’) and plot_VS_var(’Iq0’):

Evolution of Id0
Evolution of Id0
Evolution of Iq0
Evolution of Iq0
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