Improvement of Performance at Lower Speed of Direct Self-Control of Brushless DC Motor Based on DSP

The direct self control was proposed to brushless DC motor drive system. The high performance was achieved with its simple structure and the torque control was the center. In order to improve the distortion of stator flux-linkage at lower speed, the stator flux-linkage should also be controlled. In this paper, a new approach was brought forward that three voltage vectors and two zero voltage vectors were used in every 60 degree sector. The torque ripple and flux-linkage distortion at lower speed was effectively reduced. Finally, two experiments on the basis of TM S320LF2407 DSP were carried out to validate the theory.