11 - Compensation in frequency domain.

Lecture video:

Part 1.

Part 2.

Lecture notes: Chapter 11 in the lecture notes (swe Download swe,eng Download eng)

 

Graphical User Interfaces illustrating compensation in frequency domain (explanation and demo on Lecture)

designk.m

Download designk.m varierande förstärkning K

designlagnew.m

Download designlagnew.m fasretarderande länk = lag-design: K(s+a)/(s+a/M)

designleadnew.m

Download designleadnew.m fasavancerande länk = lead-design: K_k (s+b)/(s+bN)

designleadlagnew.m

Download designleadlagnew.m (båda samtidigt, med M=infty):  K(s+a)/s * (s+b)/(s+bN)

 

The code lets you experiment with compensation in the frequency domain, and helps you get familiar with the different diagrams.

Download the code to your computer, start matlab and run e.g. designlagnew.m to get at GUI with 3 sliders that change the K, a, and M parameters in a lag design, see below. The blue curve corresponds to the $\textcolor{blue}{\textrm{original system }G(s)}$ (on the lecture called $G_0(s)$ ) and the red curve corresponds to the $\textcolor{red}{\textrm{compensated system }C(s)G(s)}$ (on the lecture called $G_K(s) G_0(s)$).

Bode and Nyquist curves are for open loop systems (blue = original G_0(s), red = compensated G_K(s)G_0(s)

The lower left figure shows the poles of the closed loop systems (same colors)

The lower right figure shows simulations of the closed loop systems (step response at t=0, followed by input load disturbance at t=20, followed by output measurement noise starting at t=40)