Variable-speed torque-driven on-load sinusoidal vibro-acoustic simulation with permeance / mmf model

The aim of the simulation project is to run a variable speed simulation with a realistic traction control strategy (torque Vs speed curve characteristics). This means that a maximum flux level is specified, and the slip and phase voltage are found in order to achieve a given output mechanical shaft torque at a given speed. When the maximum voltage level is reached, it is kept to its maximum value and the field weakening region starts.

A new project is set-up in tuto_test_SCIM_16 by copy/paste tuto_test_SCIM_01 (or by loading it with the GUI). The variable speed operation is activated by specifying:

Input.Simu.is_varspeed = 1;         % 1 to run a variable speed simulation from specified N0_min to N0_max

The speed range and number of speeds are defined as

Input.Simu.N0_min=500;              % min rotation speed for variable speed mode [rpm]
Input.Simu.N0_max=5000;             % max rotation speed for variable speed mode [rpm]
Input.Simu.Nspeeds=10;              % number of different rotating speeds from N0_min to N0_max, one calculation being run at each speed []

The following parameters are modified in order to impose a specific current Vs speed curve at variable speed:

Input.Simu.type_control = 2;

Note that the input parameter Input.Simu.type_extsupply should be left to 0 as it only deals with the single speed simulation control.

The torque versus rotating speed is specified in the machine data file

Input.Simu.N0spec = [0,500,1000,1500,2000,2500,3000,3500,4000,4500,5000,5500,6000];        % rotation speed [rpm]
Input.Simu.Tspec = [2000,2000,2000,2000,2000,2000,1750,1500,1200,1000,800,600,400];         % net output mechanical torque to be achieved at variable speed [Nm]

One can notice that the specified torque is reduced above 2500 rpm which is actually the field weakening frequency specified in the simulation input as:

Input.Simu.freq_mains = 125;

With the GUI, all these parameters are gathered in the Workflow/Variable Speed:

150. Variable speed simulation setup with the GUI
Variable speed simulation setup with the GUI

You need to select "variable speed simulation" to enter the control law. The corresponding one is "Torque Vs speed curve". To enter your values, you need to click on "Add row" 13 times to get the correct table size and then enter your values. You can then check your input with the button "Preview".

Result Interpretation

The following output variables are of interest

>> run_MANATEE('tuto_test_SCIM_16')
>> plot_VS_vars({'U0rms';'I10rms';'Cout';'EsF0';'slip';’K0'})
170. Evolution of U0rms
Evolution of U0rms
170. Evolution of I10rms
Evolution of I10rms
170. Evolution of Cout
Evolution of Cout
170. Evolution of EsF0
Evolution of EsF0
170. Evolution of slip
Evolution of slip
170. Evolution of K0
Evolution of K0

One can see that the specified torque is correctly achieved. In the constant torque phase, the slip is rather high and the phase current is also constant, the phase voltage increases linearly. The maximum phase voltage specified in Input.Simu.Umax to 800 V is fulfilled, as the maximum flux Input.Simu.EFmax of 5 V/Hz.When the field weakening point is reached the torque is reduced, the current drops and voltage is kept at its maximum value.

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