Hello Daniel,
I understand that you are trying to linearize a time-variant model in Simulink which consists of three enabled subsystems that describe a periodic process, and you would like to implement three state-space models corresponding to different time snapshots.
Your assumption about the error, “Invalid Simulink object handle”, is probably right. While linearizing a model with multiple enable subsystems, the order of linearization does affect the results. It is important to ensure that the active subsystems are linearized first to capture the dynamics correctly. So, I would recommend you modify the order of enabled subsystems in your model to match the time points you want to linearize, hence ensuring that the active subsystems are linearized first.
Secondly, the ‘findop’ command in Simulink finds an operating point for the model at specified time points. It considers all state variables present in the model, regardless of whether they are active or not in a particular subsystem. This is why you may see state variables not active in a snapshot being included.
To exclude inactive state variables, I suggest you modify the ‘findop’ command by following the below code: -
op = findop(mdl, [time1, time2, time3], 'ActiveStateVariables', {'stateVar1', 'stateVar2'});
Where ‘stateVar1’ and ‘stateVar2’ are the names of the active state variables in the respective subsystems at each time point.
I suggest you to refer to this link for more information - Steady-state operating point from specifications (trimming) or simulation - MATLAB findop (mathworks.com)
If you continue to encounter errors or need further assistance, please provide additional details about your model and the specific commands you are using.
I hope this helps.
