SPEED CONTROL OF BRUSHLESS DC MOTOR USING PI, FUZZY AND HYBRID FUZZY PI CONTROLLER

Abstract

Abstract This thesis presents the comparative study of PI, Fuzzy and hybrid Fuzzy-PI controller for controlling the speed of brushless dc (BLDC) motor. The control structure of the proposed drive system is described. The simulation results of the drive system for different operation modes are evaluated and compared. Although conventional PI controllers are widely used in the industry due to their simple control structure and ease of implementation, these controllers pose difficulties when there are some control complexity such as nonlinearity, load disturbances and parametric variations. Moreover PI controllers require precise linear mathematical models. A fuzzy controller offers better speed response for start-up while PI controller has good compliance over variation of load torque but has slow settling response. The Fuzzy Logic (FL) approach applied to speed control leads to an improved dynamic behaviour of the motor drive system and an immune to load perturbations and parameter variations Hybrid controller has an advantage of integrating of these two controllers for better control performances. MATLAB/Simulink is used to carry out the simulation. BLDC motor can be modelled in the 3-phase abc variables which consist of two parts. One is an electrical part which calculates electromagnetic torque and current of the motor. The other is a mechanical part, which generates revolution of the motor. Keywords- PI, Fuzzy, Hybrid Controller, BLDC Motor and Speed control.