The modeling and simulation of sensorless brussless DC motor speed-adjusting controller

The dissertation proposes a speed-adjusting controller which is applied to a small power torpedo Servo system permanent magnet sensorless brushless DC motor (SLBLDCM). The operational theory of the 2-phase feed up, all bridge star style 3-phase 6 states SLBLDCM system are analyzed. Then the operational principles of the PWM speed-adjusting theory are analyzed. The four single chop PWM modes are introduced in SLBLDCM control system, and the mathematics model and the Matlab simulation model of SLBLDCM speed-adjusting controller are established. At last the current waveform, speed waveform and torque waveform are compared. The simulation results show that the control system has the best dynamic performance, good stability, and has a small torque waveform in HPWM-LON PWM mode. So we choose the right speed-adjusting way of SLBLDCM whine has very important practical significance for military field.