•
If there is too much overshoot due to integration reduce the integral gain by increasing
the capacitance of E.
•
You may need to increase the loop gain using B to dampen the response after selecting
E.
Also note that the higher the inductance the more proportional loop gain you will require
and the less integral loop gain you will require. So for high inductance increase B & E.
Furthermore, note that the current rate of change is limited by the supply voltage and the
load inductance by the equation
dI
dt
=
Vs
L
Ampere
/
second
and will limit the practical bandwidth of the system.
Preliminary tuning may be performed using the MATLAB script or the Simulink simulation
supplied with the system as described below.
Using the MATLAB Script
You need to have MATLAB for this. Simply run the file
current_amp_design.m
from
MATLAB. This will display a step response and a frequency response and print the
theoretical - small signal - bandwidth of the system. The system is tuned for
Rload = 4 Ohm
Lload = 0.1mHenry
If you need to tune the system for a different load, open the file with a MATLAB Editor and
change the following lines to suit your load:
% Power supply voltage
Vmax = 28;
% Load parameters - Minimum inductance 0.1 mHenry
22
Power Amplifier Module User's Guide
