Design of robust H-infinity speed controller for high performance BLDC servo drive

In Brushless DC (BLDC) motors, commutation is done externally by using a three phase inverter and therefore need more complex control algorithm as compared to brushed DC motors. BLDC motors are found to be the most suitable actuator for high performance servo drive used in robotics, industrial automation, automobiles, aerospace etc. The motor controller must adapt to the time varying motor characteristics and maintain the performance in its long service life. The controller also should be robust against external disturbances like load disturbances, measurement noise etc. This paper presents the design of robust H∞ speed controller for BLDC servo drive to address the problems mentioned above. The H∞ speed controller is designed and simulations are carried out in MATLAB/SIMULINK and its performance is compared with a PI controller.