永磁球形电机转子区间划分及辨识策略研究

Research on rotor region division and identification strategy of permanent magnet spherical motor

永磁球形电机的闭环控制,往往需要获取转子的位置信息。提出一种永磁球形电机转子区间划分方法,并对其位置进行辨识研究。根据转子磁极产生的磁场分布特点,以及定子线圈的影响来确定线性霍尔传感器的输出编码转换阈值,并且基于阈值对定子球面进行空间划分来确定传感器的安装位置和数量。转子磁极产生的磁场大于阈值的位置在定子球壳内表面构成一个近似圆形区间,将该圆形区间命名为一个单元区间,在每个单元区间的中心处放置一个传感器。多个单元区间在定子表面上相互重叠形成了范围更加小的位置区间。为了分辨磁极位置,将24个传感器输出的磁场值绝对值与磁场阈值比较后得到输出编码,命名为24位编码。将24个传感器中输出编码为1的传感器进行二次编码得到一组新的编码用来判断磁极极性,命名为极性编码。综合24位编码与极性编码来对转子位置进行辨识。为了验证所提的转子辨识理论,搭建了转子位置辨识实验平台,并且对转子的几种典型位置进行验证。实验结果与理论分析结果一致,从而验证了所提出的永磁球形电机转子位置辨识方法的有效性。

The closed-loop control of permanent magnet spherical motors often needs to obtain rotor position information.This paper proposes a method for dividing the rotor interval of a permanent magnet spherical motor,and conducts a study on its position identification.According to the distribution characteristics of the magnetic field generated by the rotor poles and the influence of the stator energized coil,the output code conversion threshold of the linear Hall sensor was determined.The stator sphere was spaced based on the threshold to determine the installation position and quantity of the sensor.The position where the magnetic field generated by the rotor poles is greater than the threshold constitutes an approximately circular section on the inner surface of the stator spherical shell.The circular section was named a unit section,and a sensor was placed at the center of each unit section.Multiple unit sections overlapped each other on the stator surface to form a position section with a smaller range.In order to distinguish the magnetic pole position,the output code was obtained after comparing the absolute value of the magnetic field value output by the 24 sensors with the magnetic field threshold value,which was named 24-bit code.The sensor whose output code is 1 among the 24 sensors was subjected to secondary encoding to obtain a new set of codes used to determine the magnetic pole polarity,which is named as the polarity code.24-bit encoding was integrated and polarity encoding to identify the rotor position.In order to verify the proposed rotor identification theory,an experimental platform was built for rotor position identification and verifies several typical rotor positions.The experimental results are consistent with the theoretical analysis results,which verifies the effectiveness of the rotor position identification method of the permanent magnet spherical motor proposed in this paper.