A Position Sensorless Control Strategy for Brushless DC Motor Based on Bus Current Hysteresis Loop

The position Sensorless technology of brushless DC motors and the suppression of torque ripple have been the hotspots and difficulties of research. This paper provides a novel digital-analog hybrid position detection method of brushless DC motor which have a neutral point. The motor bus current is used as the feedback signal of the hysteresis loop controller instead of phase current. The Sensorless control and torque ripple suppression can be realized at the same time under the bus current hysteresis loop control. This method only needs to install a current sensor on DC side of the inverter to control motor's current of each phase. Digital-analog hybrid position sensor technology has a simple structure, and can further optimize software algorithms and improve system efficiency. Simulation and experimental results verify the correctness and effectiveness of the theoretical analysis.