This is a question from control theory but I hope you can help me with it. I was pointed to this community.
So in my control loop I have elements that have cut-off frequency of 3-5kHz and I designed a PID controller for the inner loop and those elements and suddenly I get a closed loop bandwidth of 30-50kHz cut-off frequency.
So the PID controller, or voltage controller I designed is a PID with a derivative filter. Current sources are modeled as 1st order filters with 3-5kHz cutoff frequency. How is it possible to get such a high bandwidth of the closed loop if the inner elements have a lower cut-off frequency?