DefinePK

Abstract

An experimental investigation was conducted to control the speed of a permanent magnet brushed direct current motor under cascade control approach. The investigation dealt with studying the performance of the motor under open loop, current loop and speed loop conditions. The results then compared to similar investigations done by researchers. The investigation was implemented on software and hardware models with the help of MATLAB Simulink, MPLAB software and LabVIEW. PMDC motor mechanical and electrical characteristics were studied first, then they were implemented in MATLAB Simulink. A cascade control model was designed in Simulink environment and linked with the motor via H-Bridge simulation model. The cascade control has the following features, two Proportional Integral (PI) controllers, one for speed loop and the other for current loop, Integrator windup feature and some limiters. The performance of the speed control was studied successfully and motor speed was under control. The effect of tuning PI controller gains was observed. Six important tasks were focused on in this project which are Unipolar PWM generation, speed and current measurements, Integrator windup, speed transit and speed profile. The real time implementation was a success and some of the measurements were compared with a simulation model. MPLAB software was used to write the codes in C language for the cascade control loops.