Squirrel cage induction motor characteristics using SIMSCAPE

Attached AC_MOTOR_LAB_SIMULINK_MODEL_OCT24 file created with R2024b does not run in R2025b as MATLAB has removed the SPS library. Appreciate any help to modify it to work with R2025b in MATLAB online mode.

Objective is to operate the machine at different torques and obtain corresponding values of speed, stator current, Power Factor, Efficiency and slip.

I tried to modify as shown below (attached as AC_MOTOR_LAB_SIMULINK_MODEL_OCT25 but get errors when I run this. Any help will be much appreciated. This file is created with R2025b online.

Solver is encountering difficulty in simulating model 'AC_MOTOR_LAB_SIMULINK_MODEL_OCT25' at time 0.0010392594040474512. Simulink will continue to simulate with warnings. Please check the model for errors.

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Caused by:

Solver was unable to reduce the step size without violating the minimum step size value of 3.69219E-18 for 5 consecutive times at time 0.00103926. This usually may be caused by violating algebraic constraints in the differential-algebraic system or by the high stiffness of the system. Try tightening the error tolerances, and/or the tolerances for computing consistent conditions. If the problem persists, please check the system or increase the solver Number of consecutive min steps violation parameter.

Answer 1

[Umar]

Hi @Maya,

I thoroughly reviewed your block diagram. You have two issues:

Issue #1: Your R2024b model won't run in R2025b because the SPS library was removed. See: https://www.mathworks.com/matlabcentral/answers/2180147

Issue #2: Your converted R2025b model is missing critical connections. Based on your block diagram, here's the exact problem:

Critical Problem - Motor Winding Connections:

Your motor block shows ports a1, b1, c1 (input) and a2, b2, c2 (output). The a2, b2, c2 ports are not properly connected to a neutral point. This is causing your solver error at time 0.001 seconds.

Required Fix:

Add Grounded Neutral (Three-Phase) block:Path: Simscape > Electrical > Connectors & References > Grounded Neutral (Three-Phase).Connect motor ports a2, b2, c2 to this block's three inputs.Connect the neutral output to an Electrical Reference block.

Replace ground symbol at R port:Remove the ground symbol from motor R port (housing). Add: Simscape > Driveline > Rotational > Mechanical Rotational Reference.Connect to R port

Add Solver Configuration block:Path: Simscape > Utilities > Solver Configuration. Connect to electrical network. Settings: Enable "Start simulation from steady state", consistency tolerance = 1e-3

Change solver settings (Ctrl+E):Solver: ode15s (not auto).Relative tolerance: 1e-3.

Why this fixes your error: The Induction Machine Squirrel Cage block models complete stator windings. The winding ends (a2, b2, c2) must connect together to form a wye (star) configuration through the Grounded Neutral block. Without this, the electrical potentials are undefined, creating algebraic constraints the solver cannot resolve.

Test procedure: After fixes, set simulation time to 0.01 sec with zero load torque to verify motor starts.

My recommendation: Use R2024b where your original model works, or apply these specific fixes to your R2025b model.

[Maya]

Thanks for the answer.

The winding ends (a2, b2, c2) are connect together to form a wye (star) configuration through a FLOATING NEUTRAL.

I did make some changes to the solver.

MATLAB support has since made available the SPS library in R2025b as a temporary update and so I am able to run my original model file created with R2024b in R2025b.