20-08-2013, 03:33 PM
CLOSE LOOP CONTROL OF CONVERTER FED DC DRIVES
AIM :
To design and simulate a close loop Converter Fed DC drive.
THEORY:
In many application open loop operation of Dc motors may not be suitable because the torque developed by the motor increases when the speed changes when the firing angle is kept constant value .
But if the drive required constant speed operation then the firing angle has to change accordingly to maintain a constant speed. This can be achieved in a closed loop system. In close loop system the speed of the motor can be controlled according to our requirement.
In the block diagram the speed of the motor maintained constant with the help of the armature current feed back when the load increases the armature current will increase which lead to change in speed of the rotor.
In order to maintain the constant speed the armature current is feed back to the pulse triggering circuit which will produce a gate pulse with a certain firing angle which is given to the converter circuit and the speed of the motor is maintained.
Result :
Thus the close loop control of Converter Fed DC Drives was simulated using MATLAB software.