Performance analysis for open loop brushless DC motor drive

Abstract

This paper presents a broad explanation on the effect of performance of an open-loop representation of a Brushless Direct Current (BLDC) Motor drive supplied from a two-level voltage source inverter (VSI) working on 120-degree mode of conduction. This research work is programming based and it is done in the MATLAB software for both No-load and load condition. BLDC motors are currently growing popularity and replacing brush motor in so many applications, as it can be used in both low and high-speed vehicle system and also in servo drives. The high reliability, good efficiency, high power concentration, less maintenance, simplicity of control and mainly the brushless operation make the BLDC motors superior to others. The presence of electronic elements for the smooth operation of the motor makes it less costly compare to other motors. It has a permanent magnet as a rotor with a balanced 3-phase conductor assembly as armature in its stator. The armature winding is driven by a power electronics inverter which is operating the switches according to the rotor position, sensed by an optical encoder or a Hall Effect sensor. It is found that by tuning the value of rotor position, no-load condition, and trapezoidal armature phase current, the variation in torque can be minimized. Different performance parameters for no-load and load condition of the BLDC motor like phase voltages and currents, speed, electromagnetic torque, d, q axis current and rotor position etc. are determined in MATLAB environment. These parameter evaluations is necessary to achieve better performance in both load and no load condition of BLDC motor in terms of speed and torque as these are the vital point for the selection of the application field of BLDC motor drive.