Large medium-voltage electric machine stators are usually equipped with form wound coils made of flat conductors (strands) and embedded in open (rectangular) slots. Air-gap magnetic flux lines can enter the slot and, sweeping the strands placed nearest the slot opening, induce eddy currents in them. Such eddy currents cause additional losses which can be much higher than usual skin-effect and proximity losses. In order to avoid dangerous overheating and hot spots, the additional losses in question need to be carefully predicted in the design stage. Time-stepping finite-element analysis (TSFEA) can be used for the purpose, which however implies a large computational burden and requires the machine geometry to be modeled in detail. This article proposes alternative methods based on time-harmonic finite-element analysis (THFEA) simulations performed on highly simplified machine models and with no need to take rotor motion into account. The proposed methods are shown to produce very accurate results, compared to TSFEA, but with very significant time and computational savings.

中文翻译：

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开槽和任意转子几何的同步电机定子绕组趋肤效应附加损耗的快速计算方法

大型中压电机定子通常配备有由扁平导体（绞线）制成并缠绕在敞开（矩形）槽中的形状绕制线圈。气隙磁通线可以进入缝隙，并扫过最靠近缝隙开口的线束，从而在其中感应出涡流。这样的涡流会导致额外的损耗，该损耗可能比通常的集肤效应和接近损耗高得多。为了避免危险的过热和热点，在设计阶段需要仔细预测有问题的其他损失。时步有限元分析（TSFEA）可以用于此目的，但是这意味着很大的计算负担，并且需要对机器的几何结构进行详细建模。本文提出了在高度简化的机器模型上执行的基于时谐有限元分析（THFEA）仿真的替代方法，无需考虑转子运动。与TSFEA相比，所提出的方法显示出非常准确的结果，但是节省了大量的时间和计算量。