The operation of air-cored resonant induction machines is very sensitive to the tuning of the capacitors. By using the equivalent circuit equations, this article explores in detail the machine performances under four different tuning criteria: (a) both stator and rotor capacitors resonating with the stator and rotor self-inductances; (b) both capacitors resonating with the leakage inductances; (c) stator capacitors tuned to compensate for the overall stator terminal reactance and no rotor capacitors; (d) stator capacitors only to cancel out the machine ideal input reactance neglecting resistances, which is the new option introduced in this article. Extensive comparisons of all tuning options in torque, efficiency, power factor, capacitor size, and feasibility are presented and their performances are compared with a pure air-cored induction machine without capacitors. Analytic expressions for the maximum efficiency and maximum torque and related slip values are also derived as functions of the machine parameters, which provides a valuable tool for design optimization. A numerical case study based on parameters of a real air-cored induction machine is discussed and the article includes the first experimental validation to be carried out on a spinning air-cored resonant induction machine prototype. Results show that using only stator capacitors to compensate for the machine equivalent terminal reactance can be a practical choice to achieve both high torque and high efficiency and avoid rotor capacitors.

中文翻译：

---

空心谐振感应电机：电容器调谐标准与实验验证的比较

空心谐振感应电机的运行对电容器的调谐非常敏感。通过使用等效电路方程，本文详细探讨了四种不同调谐标准下的电机性能：(a) 定子和转子电容器均与定子和转子自感谐振；(b) 两个电容器都与漏电感谐振；(c) 调整定子电容器以补偿整个定子终端电抗并且没有转子电容器；(d) 定子电容器仅用于抵消忽略电阻的机器理想输入电抗，这是本文中介绍的新选项。在扭矩、效率、功率因数、电容器尺寸、提出了可行性，并将其性能与不带电容器的纯空芯感应电机进行了比较。最大效率和最大扭矩以及相关滑差值的解析表达式也作为机器参数的函数导出，这为设计优化提供了宝贵的工具。讨论了基于真实空芯感应电机参数的数值案例研究，本文包括对旋转式空心谐振感应电机原型进行的首次实验验证。结果表明，仅使用定子电容器来补偿机器等效终端电抗是实现高转矩和高效率并避免转子电容器的实用选择。最大效率和最大扭矩以及相关滑差值的解析表达式也作为机器参数的函数导出，这为设计优化提供了宝贵的工具。讨论了基于真实空芯感应电机参数的数值案例研究，本文包括对旋转式空心谐振感应电机原型进行的首次实验验证。结果表明，仅使用定子电容器来补偿机器等效终端电抗是实现高转矩和高效率并避免转子电容器的实用选择。最大效率和最大扭矩以及相关滑差值的解析表达式也作为机器参数的函数导出，这为设计优化提供了宝贵的工具。讨论了基于真实空芯感应电机参数的数值案例研究，本文包括对旋转式空心谐振感应电机原型进行的首次实验验证。结果表明，仅使用定子电容器来补偿机器等效终端电抗是实现高转矩和高效率并避免转子电容器的实用选择。讨论了基于真实空芯感应电机参数的数值案例研究，本文包括对旋转式空心谐振感应电机原型进行的首次实验验证。结果表明，仅使用定子电容器来补偿机器等效终端电抗是实现高转矩和高效率并避免转子电容器的实用选择。讨论了基于真实空芯感应电机参数的数值案例研究，本文包括对旋转式空心谐振感应电机原型进行的首次实验验证。结果表明，仅使用定子电容器来补偿机器等效终端电抗是实现高转矩和高效率并避免转子电容器的实用选择。