High power density, high efficiency, inexpensive drivetrains operating over a wide torque/speed range are critical for traction applications. An induction machine (IM) offers a cost-effective, rugged, and reliable alternative to permanent magnet solutions. Varying the IM’s pole count on-the-fly overcomes the finite inverter voltage constraint and extends the machine’s speed range. To date, the operating pole count of variable-pole IMs has been determined based on the operating speed irrespective of the torque requirement, utilizing a high pole count at low speeds and a low pole count at high speeds. This article expands the pole-selection strategy of variable-pole IMs to both torque and speed. The pole count is used to improve the machine efficiency and minimize the stator current over the entire operating torque–speed range. An experimental 36-slot toroidally wound IM driven by an 18-leg inverter validates the proposed pole-selection method for variable-pole IMs. Stator current and machine losses are reduced at partial loading conditions by utilizing lower pole counts rather than selecting the pole with the highest rated torque capability. The average loss reduction by 1/3 and torque-per-ampere improvement of $2\times $ are experimentally achieved at partial loading by using the proposed pole-selection method compared to linking the pole count solely to the operating speed.

中文翻译：

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变极感应电机的损耗最小化和每安培操作的最大扭矩

在很宽的扭矩/速度范围内运行的高功率密度、高效率、廉价的动力传动系统对于牵引应用至关重要。感应电机 (IM) 为永磁解决方案提供了一种经济高效、坚固耐用且可靠的替代方案。即时改变 IM 的极数克服了有限的逆变器电压限制并扩展了机器的速度范围。迄今为止，可变极 IM 的工作极数是根据工作速度确定的，而不管扭矩要求如何，在低速时使用高极数，在高速时使用低极数。本文将变极 IM 的选极策略扩展到转矩和速度。极数用于提高机器效率并在整个操作扭矩-速度范围内最小化定子电流。由 18 脚逆变器驱动的实验性 36 槽环形绕组 IM 验证了所提出的可变极 IM 极选择方法。通过使用较少的极数而不是选择具有最高额定扭矩能力的极，在部分负载条件下可以降低定子电流和机器损耗。与将极数仅与运行速度联系起来相比，通过使用所提出的极选择方法，在部分负载下实验性地实现了 1/3 的平均损耗降低和每安培扭矩提高 $2\times $。