Design & Development of Fuzzy Logic PID Controller for Brushless DC Motor

Abstract

The BLDC (Brushless DC) motors are used in various applications such as defense, industries, robotics, etc. In these applications, the motor should be precisely controlled to give the desired performance. The motor can be controlled using PID (proportional-integral-derivative controller) controllers. A PID controller is a control loop feedback mechanism (controller) widely used in industrial control systems. It calculates an error value as the difference between a measured process variable and a desired set point. The controller attempts to minimize the error by adjusting the process through use of a manipulated variable. Using conventional PID control method, the rapid response and satisfactory dynamic and static performance of the BLDCM (Brushless DC motor) can't be guaranteed as it generally don't work well for nonlinear systems, higher order and time-delayed linear system, particularly complex and vague system like BLDCM system. This difficulty is solved using fuzzy logic controller (FLC).The control method to combine fuzzy control with PID control is to fit the multi-variable strong coupling nonlinear characteristic of BLDCM system. The fuzzy logic controller is designed according to fuzzy rules so that the systems are fundamentally robust. The FLC has two inputs. One is the motor speed error between the reference and actual speed and the second is change in speed error (speed error derivative).Secondly, the output of the FLC i.e. the parameters of PID controller are used to control the speed of the DC Motor. The simulation results are compared to conventional PID controller for different reference speeds and are later implemented on FPGA(Field Programmable Gate Array).