基于连续位置估计的BLDC无传感器低速运行策略

he brushless DC motor (BLDC) has the advantages of high power-density, high reliability, relatively simple structure, stable speed and convenient speed regulation. However, hall sensors are usually needed to sense rotor position in BLDC driving, while sensorless technology will decrease the cost of the system and improve the reliability as a fault tolerance scheme. For the sensorless closed-loop operation of BLDC at low speed, a continuous position estimating strategy using single current sensor is proposed. Firstly, the initial position identifying strategy and the sensorless starting strategy based on discrete position are proposed by analyzing the magnetic-saturated saliency-effect of BLDC, the influence of switching mode on the stator saturation and the DC bus voltage ripple. Then, a vector tracking observer is constructed to transform the discrete position into a continuous position, and the stability of the vector tracking observer and the speed adaptability of the starting strategy are analyzed. Finally, the effectiveness of the strategy is verified by experiments.