In this paper a multizonal proportional integral (P I) speed controller for a closed loop speed
control of a separately exited dc motor is presented. The motor is fed from a dc power supply and
a Cuk converter. Step – up and step – down characteristics of the output voltage can be obtained.
A high performance is achieved with a simple control circuit having only one switch (MOSFET)
for the proposed system. The output voltage and current are smooth and free of ripples. The
converter operates in both open and closed loop speed control. A multizonal proportional integral
speed controller is used to overcome the possibility of change in the system parameters. The
proposed modeling and simulation of the proposed system are performed using differential
equations, which describe the system behavior in the different operating conditions .The run up,
transient and steady state are presented. Speed control using multizonal proportional integral speed
controller is given to satisfy the best required response for the load disturbances Also, the motor
speed can follow the desired reference speed smoothly in the different operating zones. The
experimental results will be have ensured the proposed controller robustness, simple, and powerful
control application capabilities. The experimental and simulation results of the system for both
open and closed loop speed control are verified and a good correlation between them was found.