Example 2

Explanation:

Method 1

Notice pole-zero cancellation

As such bandwidth is Ki/Rs or Kp/Lq which is 50rad/s -> 8Hz (rounded up)

Method 2

Plug it all into matlab and read the bode plot

clear all; close all; clc;
s=tf(‘s’);
R_s=0.7;
L_d=8.2e-3;
L_q=L_d;
H_el_q=1/(R_s+s*L_q);
K_p=L_q;
K_i=R_s;
g=50;
K_p2=g*K_p;
K_i2=g*K_i;
C=(K_p2+K_i2/s);
controlSystemDesigner(H_el_q,C);