An urgent problem(induction motor transfer function )

[bpetca]

I have to simulate in simulink-matlab the induction motor control.I want to know if anyone want to offer me the transfer function of the induction motor or how I can calculate the regulator parametersof speed controler and current controler

[Anshu]

Hi buddy,

The best way to get the induction motor model is to use space vectors. This reduces the number of state variables of the machine. So we are now dealing with the following state variables: stator voltage vector, stator flux vector, stator current vector, rotor flux vector and rotor current vector. Now we have a stator voltage equation (written in the space vector notation) and rotor voltage equation. Here you have to be careful about your reference co-ordinate syatem as it changes these equations. This co-ordinate system can be stationary(attached with the stator), it can be moving at synchronous speed or it can be attached with the rotor. So you get the stator and rotor voltage equations in the designated co-ordinate system. There are two more equations for the stator and rotor flux linkages. Using these four equations you can easily obtain two first order differential equations having two state variables. These can easily be configured using SIMULINK blocks. You can also include the the mechanical loading and complete the model. Regarding tuning of the controllers, You can start off with the inner current control loop (vector control) and use the ZN method to get the tuning constants. Move out for the speed loop and use the same strategy.

rgds

Anshu