Analysis of closed loop current controlled BLDC motor drive

DC motors are simple choice for drive systems having very easy speed control techniques. DC motors are used where DC supply is available. Commutation in the conventional DC motors is carried out by commutator which is rotating part placed on the rotor and brushes. Due to these mechanical parts, conventional DC motor consist high amount of losses. Brushless DC (BLDC) Motors are very extensively used motors these days because of its advantages over conventional DC motors. Commutation is carried out with the help of solid-state switches in BLDC motor instead of mechanical commutator as in conventional DC motor. This improves the performance of the motor. BLDC motor shows good speed control characteristics especially in low power applications like hard-disk drives, laser printers and many more. BLDC with current control scheme was discussed in this paper. BLDC drive with fixed speed and variable speeds are developed using Matlab/Simulink and results were shown for both fixed and variable speed applications. Basic operation of BLDC motor was explained with open loop and closed loop speed control. Matlab results were shown for BLDC motor with open loop speed control, BLDC motor for fixed speed closed loop control and BLDC motor with variable speed closed loop control.