Back EMF Based Sensorless PMBLDC Motor Control System Simulation work

This paper deals with the detailed modeling of a speed control of a sensor-less permanent magnet Brushless DC motor (PMBLDC), the MATLAB/ simulation of sensorless PMBLDC is also presented in this work. For this a closed loop control scheme with a Proportional Integral (PI) controller in the speed loop has been designed to for the generation of torque by reference speed and actual speed generated out by the motor. Now this torque is fed to a current hysteresis controller block which generates the pulses for switching on the inverter and also limits the value of current in the desired range. A three phase six pulse full bridge inverter further feds to the Brush less DC motor. The combination of BLDCM block, speed (PI) controller block, current reference block, inverter block and BLDC motor have been incorporated in this simulation model of control system for sensorless operation of BLDCM has been established and modeled in MATLAB/Simulink. The PMBLDC motors are controlled electronically and for the proper commutation of current, rotor position information is required, on the other hand the problems of the cost temperature sensitivity and reliability of position sensors have motivated the research in the area of sensor less PMBLDC motor drives.