Design Space Method for Conceptual Design Exploration of High Speed Slitted Solid Induction Motor

Abstract

Design of High Speed (HS) electric machines is an iterative process that requires a multidisciplinary design team to accomplish the required performance. In this study, a design space method (DSM) is developed to streamline conceptual designing of a high-speed and high-power electric machine. The method uses analytical equations and a rotordynamic model to determine geometrical dimensions based on the application requirements. These dimensions create a feasible baseline design for the particular application. However, considering the dimensions as design variables and using the baseline design as a starting point, a multidimensional combination and interaction of the design variables and the correlated output for the particular topology of motor and performance range can be further studied for design exploration and optimization purposes. The study includes a test case where the baseline dimensions are determined and compared to an existing machine from literature, and then further explored to identify the sensitivity of different outputs with respect to different design variables. The method enables rapid design iterations, rotordynamics and rotor mass optimization. The baseline design can be also used as a starting point for the detailed design.

Design of Thick-Lamination Rotor Configuration for a High-Speed Induction Machine in Megawatt Class

“…Therefore, the temperature effects such as creeping can be left out from baseline design. While FE-analysis are suitable for detailed design, for baseline design at conceptual stage, analytical equations can be used for identifying the stresses in the laminates due to centrifugal forces [15]. The radial and tangential stresses on the rotating laminates due to centrifugal forces can be given as:…”

“…However, for HS applications, generally active magnetic bearings (AMBs) are preferred because of their numerous advantages [18]. The general dimensioning of the rotor shaft for radial and axial AMBs at the conceptual design stage has been discussed in details in [15]. The radius of the shaft in the AMB section is roughly determined relative to the active part of the rotor.…”

“…Radials AMBs are usually separated from the sensors using a spacer to avoid electromagnetic interference between the sensor and the radial actuator. Suitable angular contact ball bearings (two for each end) based on the rotor load, speed and end shaft dimensions can be used as backup bearing [15].…”

Active Magnetic Bearing Positioning in the Conceptual Design Phase of a High-Speed Electric Machine

“…In the conceptual design phase, the computational methods are used, and verified practices are used to assess the system performance. This can be further utilized when assessing the limits of each design, as shown in Kurvinen et al [8]. The fundamental limits arise from the length of the rotor and the rotation speed of the rotor.…”

“…The length of the rotor is related to the rotation speed, i.e., the long rotor goes to resonance at a lower speed compared to the shorter rotor. The industry trend is going for higher power applications, e.g., as reported in Moghaddam, most of the machines were below 1000 kW [9] and recent examples in megawatt size have been published [8], [10] with the integrated solutions. To achieve higher power and increased speed the challenges to handle higher stresses and yet keep the dynamical performance acceptable, i.e.…”