3 Ph Induction Motor Electrical-Thermal Simulink Modelling

The Induction Motor is perhaps the most common type of electric motor in the world. It does not have a commutator or brushes. In general, the less moving parts and more simple any device is, the better the longevity. This type of motor is powerful and efficient. It is used in newer diesel trains, industrial applications, pumps, compressors, fans, dishwashers, and countless other things.

Read more about Induction Motors, CLICK HERE.

Induction motor has 3 parts:

• Electrical Model

• Thermal Model

• Mechanical Model

In my model, I neglected mechanical losses and focused on the electrical and thermal parameters and their relations.

The purpose of this project is to analyse the electrical and thermal changes due to operation modes and tests such as:

• Steady State and Transient Operations.

• Locked Rotor and Standstill tests.

• Operation Electrical Faults PH2L , SC FAULT , L2L FAUT ..etc.

So, lets start our work :D .

Electrical Model:

Read more about equations and equivalent circuit of IM, CLICK HERE.

Here, we are talking about Three Phase Induction motor, so that requires a lot of work!

To be able to analyse all electrical parameters of IM we have to transmit the machine from 3 phase model to quadrature model and vise versa, I will show you how to do that in few steps.

1- Create 3 phase AC source with 120 degree phase shift.

2- Calculate Flux.

3- Extract 4 quadratic Currents from Corresponding Flux parameters.

4- Extract electrical Torque from Current and Flux Components.

Notice: all the shown subsystems got a lot of simulink block equivalent to mathematical equations for theses transmissions.

AND THE FINAL STEP OF OUR WORK:

5- Extract A,B,C Currents for Rotor and Stator.

For making modifying your testing machine electrical parameters.

I put them in Matlab M-File and linked it to our simulink model using Tosim block.

% feel free to change parmeters :D 
% parameters %
%f -freq in hertz
f=60;
%P- no op poles
P=4;
%rs-stator resistance(ohm/phase)
rs=0.435;
%Xls -stator impedance
Xls=0.754;
%xm-magmaatizing impedance
Xm=26.13;
%Xlr -rotor impedance
Xlr=0.754;
%rr-rotor resistance
rr=0.861;
%J-rotor inertia
J=0.089;
%rpm-rated speed
rpm=1710;
%wb-base speed
Wb=377;
We=377;
%Vm-amplitude of baising
%Vph=460/sqrt(3);
%Vm=sqrt(2)*Vph;
vm=220;
%power factor
pf=0.7 ; 
save('par.mat')

Finally Spread your scoops , run M file and run simulink model to get your results.

Thermal model:

To analyse the thermal behavior of the Induction motor well, you need to know well:

• IM Power Flow tree , CLICK HERE

• Lumped Thermal Elements Method, CLICK HERE

So, all heating of IM results in origins form Electrical Power losses, and they are:

• Stator winding losses

• Rotor Winding Losses

• Stator Iron Losses

• Rotor Iron Losses: This one is neglected because ,iron losses depending on frequency and F is too small in rotor circuit due to slip.

The gray subsystem above is the link between electrical model signals (rotor and stator currents) and physical thermal model.

Gray block contains all blocks that simulates power losses equations. and convert simulink signals to physical signals.

The Red Subsystem contains the representation of all Lumped elements of IM.

For all the 10 elements above, we have to simulate the specs of each material and the effect of CONDUCTION AND CONVECTION heat transferring on it.

Then we scoop 4 temperature Signals.