Hi @Rohan
In the Thesis, you can probably explain like that
"When the 'Tune' button is clicked, the Simulink PID Tuner does not function properly because the plant cannot be linearized or linearizes to zero. Specifically, the permanent magnet synchronous motor with a Hall sensor may exhibit special nonlinear characteristics that cannot be mathematically linearized under the selected or any operating conditions. PID tuning in Simulink is a model-based optimization approach aimed at achieving a good balance between performance and robustness as specified by the PID control practitioner. The tuning algorithm requires a linear mathematical model, whether in state-space representation or as a transfer function. If the linear model is unavailable, the algorithm will attempt to compute a linear model of the plant within the Simulink model. From the perspective of the PID Tuner, the combination of all blocks between the PID controller output and input is considered the plant. Thus, if these blocks contain nonlinearities, they will be linearized to the specified operating conditions. However, not all types of nonlinearities can be linearized; for example, the discontinuity at zero in a signum function cannot be linearized. When this occurs, one option is to design a PID controller based on simulated frequency-response data. The steps to design a PID controller from the plant's frequency-response data are described below: blah, blah, blah..."
