I'm currently using SimPowerSystems to model a DC-DC buck converter which regulates the output voltage to 5V. Using the closed-loop configuration, when I try to auto-tune the PID values, I get a message that says linearization failed.
However, when I try to replace the SimPowerSystems block with a control-to-output buck transfer function obtained using state-space analysis, the PID tuning works successfully. What did I do wrong with the SimPowerSystems block? I personally prefer modelling using SimPowerSystems since using these blocks, I can see the voltage and current waveforms in each component. However, I still can't get the PID tuning to work.
I have attached my simulink model with this question.