Sensorless FOC for PMSM with BEMF estimator

Hi, by running my model I have this error message (Error using parametre_moteur (line 65) Simulink cannot solve the algebraic loop containing 'Cmde_estimateur_vitesse_position/Sum1' at time 0.0002250000000003423 using the TrustRegion-based algorithm due to one of the following reasons: the model is ill-defined i.e., the system equations do not have a solution; or the nonlinear equation solver failed to converge due to numerical issues. To rule out solver convergence as the cause of this error, either a) switch to LineSearch-based algorithm using set_param('Cmde_estimateur_vitesse_position','AlgebraicLoopSolver','LineSearch') b) reducing the ode45 solver RelTol parameter so that the solver takes smaller time steps. If the error persists in spite of the above changes, then the model is likely ill-defined and requires modification.) that I can not solve and I need your help please. thank you in advance

Answer 1

[Sabin]

The error message indicates that Simulink has detected an algebraic loop in your model. This means that there is a circular dependency where the output of a block depends (directly or indirectly) on its own input in the same time step, and Simulink cannot solve this.

Possible solutions:

• Try switching to the LineSearch-based algorithm by running this command in MATLAB (as suggested by the error message): set_param('Cmde_estimateur_vitesse_position','AlgebraicLoopSolver','LineSearch')
• reducing the solver RelTol parameter so that the solver takes smaller time steps
• If the above does not work, the model may be ill-defined. Try to break the algebraic loop by adding a Unit Delay (or transfer function) in the loop.