High-speed solid-rotor induction machines (HSIMs) are popular within high-speed (HS) applications because of their high rotor structural integrity and their fairly well-established manufacturing process guaranteeing high quality series products. Designing a new HS electric machine requires a multidisciplinary team to accomplish the machine performance desired. In case of a HS machine design, the components and applied materials often reach their physical limits at the rated operating condition. Therefore, the design process is highly iterative and, thus, a systematic approach has a high potential to reduce the time of the design phase significantly. In this article, a systematic design process is proposed for a modular, multimegawatt (MMW) HSIM with three radial active magnetic bearings. The process includes a traditional multidisciplinary design flow with extra critical aspects of MMW HS machines: manufacturability, bearing system, housing, and operating unit. In addition, the manufactured machine is reported. The proposed systematic design process is described, including several multidisciplinary critical design aspects of HS machinery.

Non-contact rotor position sensors are an essential part of control systems in magnetically suspended high-speed drives. In typical active magnetic bearing (AMB) levitated high-speed machine applications, the displacement of the rotor in the mechanical air gap is measured with commercially available eddy current-based displacement sensors. The aim of this paper is to propose a robust and compact three-dimensional position sensor that can measure the rotor displacement of an AMB system in both the radial and axial directions. The paper presents a sensor design utilizing only a single unified sensor stator and a single shared rotor mounted target piece surface to achieve the measurement of all three measurement axes. The sensor uses an inductive measuring principle to sense the air gap between the sensor stator and rotor piece, which makes it robust to surface variations of the sensing target. Combined with the sensor design, a state of the art fully digital signal processing chain utilizing synchronous in-phase and quadrature demodulation is presented. The feasibility of the proposed sensor design is verified in a closed-loop control application utilizing a 350-kW, 15,000-r/min high-speed industrial induction machine with magnetic bearing suspension. The inductive sensor provides an alternative solution to commercial eddy current displacement sensors. It meets the application requirements and has a robust construction utilizing conventional electrical steel lamination stacks and copper winding.