Multiphase machines are a promising alternative for high-reliability applications. In these applications, overmodulation (OVM) is important since it allows attaining higher modulation indices by injecting, besides zero-sequence voltage harmonics, current-producing ones. In general, the existing techniques are able to limit to some extent the current total harmonic distortion (THD). However, most do not ensure the minimum current THD, thereby not guaranteeing the minimum harmonic stator copper loss. Furthermore, most are intended just for particular phase numbers $n$ , symmetrical/asymmetrical winding arrangements and neutral-point (NP) configurations. OVM with low THD remains unaddressed in most types of multiphase motors. This article overcomes these limitations by proposing a generalized OVM strategy that attains the minimum current THD in induction motors with any $n$ , winding arrangement, and NP configurations. Two techniques are outlined. One of them injects only non-torque-related harmonics, while the other technique exploits torque-producing harmonics to further reduce the current THD and to attain modulation indices up to square waveform. The superiority of the proposal in terms of current THD is substantiated through studies for multiple kinds of multiphase machines. The experiments are performed by using two six-phase induction motors with symmetrical/asymmetrical windings when 1 and 2 NPs are set.

中文翻译：

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用于对称和不对称多相感应电机驱动的具有最小电流失真的广义过调制策略

多相电机是高可靠性应用的一个有前途的替代方案。在这些应用中，过调制 (OVM) 非常重要，因为除了零序电压谐波之外，它还可以通过注入产生电流的谐波来获得更高的调制指数。总体而言，现有技术能够在一定程度上限制当前的总谐波失真(THD)。但大多不能保证最小电流THD，从而不能保证最小谐波定子铜损。此外，大多数仅适用于特定的相数$n$ 、对称/不对称绕组布置和中性点 (NP) 配置。在大多数类型的多相电机中，低 THD 的 OVM 仍未得到解决。本文通过提出一种通用 OVM 策略克服了这些限制，该策略可在任何情况下在感应电机中实现最小电流 THD。$n$ 、绕组排列和 NP 配置。概述了两种技术。其中一种技术仅注入与扭矩无关的谐波，而另一种技术则利用产生扭矩的谐波来进一步降低电流 THD 并获得高达方波的调制指数。通过对多种多相电机的研究证实了该方案在当前 THD 方面的优越性。实验使用两台具有对称/不对称绕组的六相感应电机，设置 1 个和 2 个 NP 时进行。