Linear induction motors (LIMs), applied in the field of electromagnetic emission, due to end effect, show the characteristics of thrust rapid decline, and current asymmetry increasing in the process of high-speed movement. This article studies the effect of stator winding connections on thrust and current asymmetry of six-phase shifted 30° LIM considering the static and the longitudinal end effect. The study compares three connections by finite-element analysis, namely, open-end, star, and triangular connections. The theory of symmetric component method is introduced to analyze the asymmetric characteristics caused by the end effect. The output thrust and current asymmetries of the motor under three connection modes are compared in detail. The simulation results show that there is no difference among the three connection modes when only considering static end effect, but once considering dynamic end effect, the output current symmetry of star connection is better than that of the open and triangular connection. Also, Adopting variable slip frequency control method can not only improve output thrust of motor, but also improve current symmetry, especially at high speed obviously, when compared with constant slip frequency control method. The research will be helpful to motor thrust optimization control and winding design in the future.

中文翻译：

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考虑端部效应的绕组连接对直线感应电机推力和电流不对称性的影响

应用于电磁辐射领域的直线感应电机（LIMs），由于端部效应，在高速运动过程中表现出推力快速下降、电流不对称性增大的特点。本文研究了定子绕组连接对六相移 30° LIM 推力和电流不对称性的影响，同时考虑了静态和纵向端部效应。该研究通过有限元分析比较了三种连接，即开口连接、星形连接和三角形连接。引入对称分量法的理论来分析端部效应引起的不对称特性。详细比较了三种连接方式下电机的输出推力和电流不对称性。仿真结果表明，仅考虑静态端部效应时，三种连接方式之间没有差异，但考虑到动态端部效应时，星形连接的输出电流对称性优于开路和三角形连接。另外，采用变滑差频率控制方式不仅可以提高电机的输出推力，而且与恒滑差频率控制方式相比，可以明显改善电流对称性，尤其是在高速时。该研究将有助于未来电机推力优化控制和绕组设计。采用变滑差频率控制方式，与恒滑差频率控制方式相比，不仅可以提高电机的输出推力，而且可以明显改善电流对称性，尤其是在高速时。该研究将有助于未来电机推力优化控制和绕组设计。采用变滑差频率控制方式，与恒滑差频率控制方式相比，不仅可以提高电机的输出推力，而且可以明显改善电流对称性，尤其是在高速时。该研究将有助于未来电机推力优化控制和绕组设计。