Closed Loop Control for a Brushless DC Motor to Run at the Exactly Entered Speed

Abstract

The project is designed to control the speed of a BLDC motor using closed loop control technique. BLDC motor has various application used in industries like in drilling, lathes, spinning, elevators, electric bikes etc. The speed control of the DC motors is very essential. This proposed system provides a very precise and effective speed control system. The user can enter the desired speed and the motor will run at that exact speed. Based on the principle of PWM speed can be controlled. This is achieved by keeping BLDC motor on closed loop feedback by giving RPM reference to the microcontroller upon a shaft mounted IR reflection arrangement. The pulse width modulation would be automatically adjusted to maintain the DC power to the motor such that entered speed percentage matches the RPM. An LCD duly interfaced to the microcontroller to display the running speed. The desired speed in percentage of full speed is fed with the help of keypad. The controller delivers desired pulse width to automatically adjust the DC power to the motor for required speed. The above operation is carried out by using one thyristor for driving the BLDC motor with IR sensing for getting the speed reference to the microcontroller. The power supply consists of a step down transformer 230/12V, which step down the voltage to12V AC. This is converted to DC using a Bridge rectifier and it is then regulated to +5V using a voltage regulator. Which is required for the operation of the microcontroller and other components Further the project can be enhanced to a fully-fledged fuzzy logic control of a BLDC motor for industrial applications. It can also be developed for an intelligent cruise control used in modern auto mobiles these days..