DSP-based brushless DC motor sensorless drivers with sine PWM

This paper presents a brushless DC motor sensorless driver with sine pulse width modulation signal. For speed control, the current feedback is included to the closed loop control strategy to decrease the power consumption and increase the motor performance. In addition, the sine wave phase-changing signal is closed with a set of specific electrical angles in the zero crossing point to detect the back electromotive force and observe the output performance. A simple mathematical model of brushless DC motor is derived, and the control strategy is implemented by digital signal processing (DSP) platform. The validity of the method is verified by the experiments.