The end-winding region is usually overlooked in the roebel design of large AC machines. However, saturated stator slots cause overhang parts to impact the circulating currents significantly. In fact, a precise knowledge of the winding overhang strand inductances is crucial when optimising the transpositions of large roebel bars, especially in the case of under-roebeling (having less than 360-transposition in the active part) where the goal is to compensate the winding overhang parasitic field with the slot-parasitic field. In this paper, a rectangular inductance calculation model (R-ICM) is proposed. It results in a circuital lumped-element model (LEM) that takes the strand dimensions, the bar bending, as well as small-scale effects into account. Moreover, the work describes how to model finite current-carrying rectangular segments (straight and arced) from first principles. Finally, the methodology was demonstrated for two prototype specimens with different bending-shapes corresponding to the fundamental elements on a stator bar in the winding overhang of large electrical machines.

中文翻译：

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用于增强交流电机循环电流预测的矩形端绕组模型

在大型交流电机的 roebel 设计中，端部绕组区域通常被忽略。然而，饱和的定子槽会导致悬垂部分显着影响循环电流。事实上，在优化大型 roebel 条的换位时，准确了解绕组悬垂线电感是至关重要的，尤其是在下 roebeling（活动部分的换位少于 360 次）的情况下，其目标是补偿绕组悬垂寄生场与槽寄生场。本文提出了一种矩形电感计算模型（R-ICM）。它产生了一个电路集总元件模型 (LEM)，该模型考虑了绞线尺寸、钢筋弯曲以及小规模效应。而且，这项工作描述了如何根据第一原理对有限载流矩形段（直线和弧形）进行建模。最后，该方法针对具有不同弯曲形状的两个原型样品进行了演示，这些样品对应于大型电机绕组悬垂中定子线棒上的基本元件。