Abstract
As the reduction in manufacture costs and popularity of power electronic devices in the recent years, today brushless DC motors have been employed for applications in aerospace, automotives, and home electronic products. By replacing the mechanical commutator in brush DC motors, brushless DC motors have been known for their advantages in low noise, long life, high efficiency, and maintenance free. However, brushless DC Motors have to rely on detecting rotor position for properly initiating the electronic commutation; hence, Hall elements are commonly employed for detection of rotor position whereas the life cycle and costs have become an important factor in applications. In this thesis, detection of rotor position for brushless DC motor has been implemented via back EMF monitoring which adopted pre-filters and phase-angle compensators so that the correct rotor position could be determined. Furthermore, compensation of phase-angle versus operational speeds have been established for adjusting the optimal commutation angles. The commutation angles were then used for the trigger signals on the power electronic switches to drive the brushless DC motors. Finally, two commercial models were employed for experimental verifications and comparisons on the proposed method which was implemented on a digital signal processor. Hopefully, the results can contribute valuable information for the industrial drive technology.