低速下无刷直流电机三相电压矢量位置检测方法

Position Detection Method of Brushless DC Motor Used at Low Speed Utilizing Three-Phase Voltage Vector

提出一种适用于无刷直流电机低速运行时的无位置传感器控制方法,该方法依据相间反电动势差值进行转子位置检测,通过施加两个相位相差120°的三相电压矢量,分别采样矢量作用结束时刻的直流侧响应电流并比较其大小关系判断转子位置。同时分析了磁路饱和效应和电压矢量作用时间对位置检测精度的影响。与传统电感法相比,该方法检测矢量少,缩短了检测时间;与长短脉冲位置检测方法相比,在相同条件下响应电流差值大,更易于检测,提高了换相准确性。实验结果验证了所提方法的有效性。

This paper presents a sensorless control method of brushless DC motor suitable for low speed condition. This method estimates the rotor position according to the difference value of the electromotive force between stator phases. By applying two three-phase voltage vectors which have a 120°phase angle difference, the response current of DC side is sampled at the end time of each vector,and its value relationship is compared to determine the rotor position. The paper analyzes the effects ofthe stator iron saturation and voltage vector on accuracy bias of position detection. Compared with the traditional inductance method, this method uses less detection vectors and reduces the detection time.Compared with the long-short pulse position detection method, the difference value of response current is larger, which is easier to be detected under the same condition. The accuracy of the commutation can be improved. Experimental results demonstrate the effectiveness of the proposed method.