This article deals with the determination of the rotor time-constant of an induction machine by performing a flux-decay test in generic load conditions. The flux-decay transient occurs when the supply stator voltage is turned off suddenly. In this way, from the decay envelope of stator back-electromotive forces and, in the case of the wound rotor machine, from that of the rotor currents, the rotor time-constant can be extrapolated with a high level of accuracy. In this article, an in-depth analysis of this methodology is reported, whose validation has been carried out on both the squirrel cage and wound rotor motors. The estimated value of rotor time-constant can be used for the machine torque regulation, using the well-known control schemes presented in the literature and whose performance in the low-speed operation is affected by the detuning of this parameter. Since the inverter-fed motors nowadays characterize most of the share in the market of adjustable speed drives, experimental results concerning the flux decay test performed under the pulsewidth modulation supply are also presented.

中文翻译：

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磁通衰减测试：评估感应电机转子时间常数的可行解决方案


本文讨论通过在一般负载条件下执行磁通衰减测试来确定感应电机的转子时间常数。当电源定子电压突然关闭时，会发生磁通衰减瞬态。这样，根据定子反电动势的衰减包络线，并且在绕线转子电机的情况下，根据转子电流的衰减包络线，可以高精度地推断出转子时间常数。本文对该方法进行了深入分析，并在鼠笼式电机和绕线转子电机上进行了验证。转子时间常数的估计值可用于机器扭矩调节，使用文献中提出的众所周知的控制方案，其低速运行的性能受到该参数失谐的影响。由于当今变频电机占据了可调速驱动器市场的大部分份额，因此还介绍了在脉宽调制电源下进行的磁通衰减测试的实验结果。