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How to set solver for control loop simulation?

I have been developing a simulation of the field oriented control of the three
phase squirrel cage induction motor (control is oriented by the rotor flux).
I have been using the Xcos which is an equivalent of the Simulink software.
The simulation block diagram looks in this manner

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Basically there are three main blocks

  • IM model

    -state space model of the induction motor in the continuous time domain

  • Observer

    -discrete block which calculates the unmeasurable components of the rotor
    flux space vector

  • Vector control

    -discrete block which calculates reference values of the components of the
    stator voltage based on given reference value of the flux and torque
    components of the stator current

I used the default setting of the Xcos solver i.e.

enter image description here

As soon as I start the simulation I receive following error message:
Simulation problem: CVode: At t=0.78087, mxstep steps taken before reaching tout
comming from the IM model block

enter image description here

and the simulation ends. I have attempted to find some information about this error and I have found that it is caused by an algebraic loop detected by the solver and it can be solved by reducing solver tolerances in the simulation setup. I thought that the algebraic loop is broken by the first order low pass filters at the inputs of the S/H blocks. Nevertheless I tried to reduce the solver tolerances

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and I run the simulation again. This resulted into another error message –
Simulation problem: singularity in a block again comming form the IM model block. This time from different place

enter image description here

Can anybody give me an advice how to resolve this issue or tell me what is going
on in my simulation? Thank you in advance for any ideas.

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