Authors: Krishan K. Sharma
Addresses: Electrical Engineering Department, NIT Kurukshetra, Kurukshetra-136119, Haryana, India
Abstract: Brushless DC (BLDC) motor applications are increasing rapidly in electrical drives due to its advantages of low weight, low volume and high efficiency. However, the cost of these drives is higher due to higher magnet cost and complex control. Although efforts are being made to avoid the mechanical position sensors, still they are used in most applications. In this paper, a simple binary controller is selected for detailed study. The two performance indices, speed ripple and steady state speed error, are used for evaluation towards a number of speed ranges keeping the load torque constant. The steady state speed error is minimised for each speed range. The performance indices are further calculated for the same speed ranges with different load torques. It has been demonstrated in this work that the variations of speed ripple with speed and torque provide definite patterns which can be used to meet the system design for specific applications. The effect of varying the current conduction ratio of the controller on the speed ripple has also been discussed.
Keywords: average speed; brushless DC motors; BLDC motors; conduction ratio; speed ripple; steady state speed error; binary controllers; load torque.
International Journal of Mechatronics and Automation, 2013 Vol.3 No.3, pp.171 - 180
Received: 17 Mar 2012
Accepted: 24 Jan 2013
Published online: 29 Jul 2013 *