The speed of separately excited DC Motor speed may be controlled above and below the rated value using DC-DC Converter. The desired speed can be achieved by applying proper DC voltage to the armature of the DC motor. The beauty of chopper is that it may provide variable DC voltage to the motor. The variable DC source is possible by properly firing the controlled power semi-conductor after receiving signal from the controller. The output of the controller is used to generate triggering pulses for the DC-DC converter circuit. The controller could be a PI, fuzzy logic or any other controller. The fuzzy logic provides faster control with no delay. In this research paper, the mathematical modelling of separately excited DC Motor is done. The speed of the motor is measured. The PI controller and fuzzy logic controller have been designed to minimize the error. After the simulation is carried out it is observed that fuzzy controller performed better than PI controller. The simulated results are presented.