Modern speed control of separately excited DC Motor by Boost converter fed field control method

In this paper, an innovative technique of the speed control of the separately excited DC Motor by Boost converter fed field control is being discussed. Purpose of a motor speed controller is to take a signal representing the required speed and to drive a motor at that speed. Controlling the PWM duty cycle is equivalent to controlling the motor field winding terminal voltage, which in turn adjusts directly the motor speed. By adjusting the duty cycle of the IGBT then the output voltage is varied. This voltage is above the rated voltage. If we can apply this voltage to the field winding, the flux production is more than the normal level. Due to this, automatically speed will be decreased. By providing one variable series resistance in the output terminal of the chopper, then if it is varied means, the current flow through the field winding is limited. By this condition, the flux production is less. Now the speed will be going to increases. In this method, the field winding should be designed for above the rated voltage. This work is a feasible one and high feasibility according to economic point of view and accuracy. In this work, developmental design of hardware of a closed loop dc motor speed control system by field control with PI speed controller have been explained and illustrated.