Back-EMF based Control of BLDC Motors using Pulse Width Modulation Technique

Abstract

A brushless DC motor that does not have the physical brushes and does its work through electronic commutation. It has low maintenance and a longer life span while being of high operating efficiency. Motor control methods have been developed and both of these methods have been implemented in this work to analyze the performance of a Brushless DC (BLDC) motor. This purpose of this work was to evaluate how the speed (RPM) of the BLDC motor changes as the voltage levels vary (from 1V to 24V). The Proposed method eliminates the Hall Sensor and using the back-EMF signals for rotor estimation, thereby reducing system complexity and cost. The Hall sensor informs the controller of the motor's position in the sensor based approach while in the sensorless method, the motorʹs position is estimated with the back-EMF theory. This contributes to lowering costs. The RPM range for motors without sensor RPM is from 120 RPM to 2880 RPM and for motors with sensors from 99 RPM to 2180 RPM. This allows the BLDC motors to enhance the effective control system reliability at low cost. It has many useful applications in electric vehicles, automated tools usage and robotics.