Dynamics of high-power multi-rotor system

Abstract Typically, active magnetic bearings have been applied to high-speed rotors in medium to high power range to replace ball, roller, and oil-film bearings. They require less maintenance and provide number of unique benefits owing to contactless suspension and active control. Integrated compressor or turbines result in predictable rotor dynamics. This allows use of model-based controllers. The model-based centralized controllers outperform decoupled transfer function controllers, but they do require accurate plant models. For integrated wheels on a single rotor the control models comprise a rigid rotor and lowest frequency bending modes. The bending mode parameters related to node locations can be identified yielding controllers tuned to the applications. This work introduces drive train modelling and magnetic levitation control of 2 MW rotor and external load with flexible coupling. The model-based control is tested in the experimental setup and drive train frequency responses are compared to the modelled multi-rotor drive train dynamics

Design of thick-lamination rotor configuration for a high-speed induction machine in megawatt class

Abstract Solid rotors are preferred choice of topology for high-speed applications due to their robustness against high centrifugal forces at high speeds, ease of manufacturability, and higher temperature range. However, for peripheral speeds lower than 200 m/s, laminated rotor structure is preferred because of lower eddy current losses resulting in higher efficiency. However, laminated rotors are complex to manufacture, sensitive to temperature and have vibration and mechanical integrity related issues. As a compromise between these two designs in terms of mechanical strength and efficiency, this study investigates a radial flux 2 MW, 15 krpm induction motor rotor core made of thick laminations. The baseline dimensions of the thick-lamination rotor design are calculated using analytical equations considering aspects such as mechanical stresses, rotordynamics, and bearing parameters. Lastly, the lamination to lamination contact behavior under unbalance load is analyzed for a simplified model and their effect on natural frequencies is studied

Physics-based digital twins merging with machines:cases of mobile log crane and rotating machine

Abstract Real-world products and physics-based simulations are becoming interconnected. In particular, real-time capable dynamic simulation has made it possible for simulation models to run in parallel and simultaneously with operating machinery. This capability combined with state observer techniques such as Kalman filtering have enabled the synchronization between simulation and the real world. State estimator techniques can be applied to estimate unmeasured quantities, also referred as virtual sensing, or to enhance the quality of measured signals. Although synchronized models could be used in a number of ways, value creation and business model development are currently defining the most practical and beneficial use cases from a business perspective. The research reported here reveals the communication and collaboration methods that lead to economically relevant technology solutions. Two case examples are given that demonstrate the proposed methodology. The work benefited from the broad perspective of researchers from different backgrounds and the joint effort to drive the technology development towards business relevant cases