In rotating flux pumps, a rectified voltage, with non-zero DC component, is obtained at the terminals due to the combined effect of the distributed AC electromotive force, produced by one or more permanent magnets in circular motion and the non-linear resistivity of the superconductor. Overcritical currents are continuously induced in the tape during operation, giving rise to the DC voltage and producing, at the same time, dissipation. In this paper, the energy behavior of the flux pump is numerically investigated. It is shown that induced currents interact with the rotating magnet(s), producing a resistant torque that is little affected by the output current of the flux pump. Due to this interaction mechanism, a significant part of the mechanical power supplied to the rotor is converted into Joule heating within the tape. The paper also explores the operational limits of the flux pump, showing that the generator operation, involving an electric power delivered to the load combined with a mechanical power supplied to the rotor, can only be achieved in a restricted range of current and voltage at the terminals and that the maximum power transfer and efficiency are reached at the middle of the generator range. Under no conditions, the mechanical torque produced on the rotor can be reversed, reaching the motor mode involving an electric power absorbed at the terminals combined with a mechanical power produced on the rotor. A revised equivalent circuit comprising, besides the effective resistance reported in the literature, a further intrinsic resistance is proposed in the paper for taking all the dissipation mechanisms into account. It is shown that this equivalent circuit can predict the energization of an RL load both concerning the final steady values and the full time-domain behavior of the current (including ripples).

中文翻译：

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发电机式通量泵的能量平衡、效率和运行限制

在旋转磁通泵中，由于一个或多个圆周运动的永磁体产生的分布式交流电动势和非线性电阻率的共同作用，在端子处获得具有非零直流分量的整流电压超导体。在运行期间，磁带中不断感应出超临界电流，从而产生直流电压并同时产生耗散。在本文中，对通量泵的能量行为进行了数值研究。结果表明，感应电流与旋转磁体相互作用，产生受磁通泵输出电流影响很小的阻力转矩。由于这种相互作用机制，提供给转子的机械能的很大一部分在带内转化为焦耳热。该论文还探讨了通量泵的运行限制，表明发电机运行涉及输送到负载的电能和提供给转子的机械能，只能在受限的电流和电压范围内实现端子，并且在发电机范围的中间达到最大功率传输和效率。在任何情况下，在转子上产生的机械扭矩都不能反转，从而达到涉及在端子处吸收的电功率与在转子上产生的机械功率相结合的电机模式。除了文献中报告的有效电阻外，本文还提出了一种改进的等效电路，用于考虑所有耗散机制。