Analysis of BLDC Motors and Modeling of Sensorless Drive Efficiency Optimization Control for Single-Phase Brushless

This thesis develops efficiency optimization control strategies for single-phase brushless dc (BLDC) motors with or without Hall sensor. A simple modeling method with feasible parameter identification is proposed to meet characteristics of single-phase BLDC motors. The nonlinear rotor flux distribution is modeled by a look-up table. With simulation assistance, the proposed model has been verified with measurement results. Experimental implementation has been constructed on a single-chip DSP controller (TMS320LF2407A) to verify the performance and feasibility of the proposed control strategies. When using the control scheme with Hall sensor, experimental results show that there are at least a 12 % reduction for average value of dc-link current, a 10 % reduction for RMS value of phase current, and a 42% reduction for peak value of phase current. When using sensorless commutation control, the fan motor can start-up smoothly and operate under wide speed range, moreover, the overall efficiency is almost the same to the results of control scheme with Hall sensor.