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problem with PID tuning / Estimating frequency response of simulink model

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i am having problem in designing PID (4 PI controller) for simulation model (vector control of induction motor). with PID tuner, it say linearization is failed.then i tried for Estimated Frequency Response by.
>> mdl = 'vcim'; %% simulink model vcim.mdl
>> open_system(mdl);
>> sim(mdl);
>> io = getlinio(mdl)
1x1 vector of Linearization IOs:
--------------------------
1. Linearization input-output located at the following signal:
- Block: vcim_d/Bus Selector1
- Port: 4
- Signal Name: speed (wm)
>> linsys = linearize(mdl,io)
d =
<Rotor speed
<Rotor speed 1
Static gain.
>> in = frest.Sinestream('Frequency',logspace(-1,1,50),'Amplitude',1e-3);
>> sys= frestimate(mdl,io,in);
---
after writing 'frestimate(mdl,io,in)' it take *too long time* to evaluate , even i could not evaluate above command after waiting for *half an hour* . it is cumbersome to use this method on my laptop config(Processor: Intel(R) Pentium(R) CPU B960 @ 2.20GHz (2 CPUs), ~2.2GHz).
even my simulation of model takes long time with
variable step solver(max step size 1e-6)
solver ode23tb (stiff/TR-BDF2)
at simulation time .1 sec

Accepted Answer

Arkadiy Turevskiy
Arkadiy Turevskiy on 18 Mar 2013
Edited: Arkadiy Turevskiy on 18 Mar 2013
It is hard to troubleshoot without seeing the model. The fact that you are using SimPowerSystems makes it possible that you have high frequency switching, like in PWM block. Your simulation step of 1e-6 is very small, so such a small step and high frequency switching may result in long simulation times.
If you have a valid license, you can contact technical support for help by clicking here.
Otherwise, take a look at some of the examples below, maybe one of them will help you figure out a solution for your problem.
HTH.
Arkadiy
  1 Comment
Abdelhedi Riadh
Abdelhedi Riadh on 5 Jan 2015
Hi,
i have the same problem in Simulation Time >> in = frest.Sinestream('Frequency',logspace(-1,1,50),'Amplitude',1e-3); Please i need Help i wana to tuning Pid pramaters for Boost converter :/

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