Torsional Excitation Upon Short-Circuit in Induction Motors - In Conventional and High-Speed Trains

Tutoria

Torsional Excitation Upon Short-Circuit in Induction Motors - In Conventional and High-Speed Trains

Tutoria

Linking technological system architecture and purchasing categories

Though the link between technological system architectures and buyer-supplier relationships has been actively studied, no comprehensive framework connecting system structures and component purchasing categories exists. We examine the technological dependency structures of such systems by adopting the buyer’s viewpoint as system assembler and integrator. We articulate how system dependencies relate to switching costs and needs for investments and technological expertise in buyer-supplier relationships. By examining the extents and directions of indirect and direct dependencies at the technological systems level, we are able to identify the purchasing category to which each component is most likely to belong. We demonstrate our theoretical framework using an empirical example of a technological system from the energy industry

Nonlinear multidisciplinary design approach for axial-flux eddy current brakes

This paper introduces a new nonlinear multidisciplinary design approach (NMDA) for axial-flux (AF) eddy current brakes (ECBs). The proposed NMDA is developed by nonlinear magnetic-thermal-structural coupled modeling. The nonlinear behaviors of the AF-ECB covering the BH curve, resistivity, heat capacity, thermal conductivity, and the temperature are jointly analyzed in time domain to investigate the actual brake properties and to determine brake operating range. In this paper, the nonlinear magnetic modeling based on two-dimensional (2-D) reluctance network is studied by a modified Newton-Raphson method. Furthermore, the nonlinear thermal modeling is carried out by lumped-parameters considering the change of heat capacity, thermal conductivity, and the temperature and updating the data in the evaluation process. Finally, the nonlinear structural modeling is performed to obtain the deflection and the mechanical safety factor of the brake. The nonlinear modeling methods in the proposed NMDA are validated by independent 3-D electromagnetic, thermal, and structural finite element analyses (FEAs), and the proposed NMDA is tested with two different AF-ECB prototypes. The experimental results confirm that the proposed NMDA has high accuracy, and compared to 3-D-FEA approaches, it provides a fast solution to predict the AF-ECB performance

Magneto-thermal analysis of an axial-flux permanent-magnet-assisted eddy-current brake at high-temperature working conditions

This article proposes an analytic coupled magneto-thermal analysis of an axial-flux (AF) permanent-magnet-assisted (PMA) eddy-current brake (ECB) at high-temperature working conditions. In the topology investigated, permanent magnets (PMs) are placed into stator slot openings to increase the braking torque production capability. This modification enables to control the magnet flux by altering the dc excitation current. However, the utilization of PMs will make the construction vulnerable at high operating temperatures simply because the magnet properties and the brake capability are strongly dependent on temperature. Such problems require complex coupled multiphysics finite-element analyses to obtain the actual brake performance. The proposed approach offers a simple and effective solution that consists of magnetic and thermal models, which are coupled to each other in the time domain. The nonlinear electrical, magnetic, and thermal properties are influenced by the temperature variation in time. An AF-PMA-ECB prototype is manufactured to validate the proposed coupled models and the experimental studies confirm that the proposed approach provides very practical results to determine the working conditions of the AF-PMA-ECB at high-temperature operations

Commissioning and control of the AMB supported 3.5 kW laboratory gas blower prototype

This paper presents the practical results of the design analysis, commissioning, identification, sensor calibration, and tuning of an active magnetic bearing (AMB) control system for a laboratory gas blower. The presented step-by-step procedures, including modeling and disturbance analysis for different design choices, are necessary to reach the full potential of the prototype in research and industrial applications. The key results include estimation of radial and axial disturbance forces caused by the permanent magnet (PM) rotor and a discussion on differences between the unbalance forces resulting from the PM motor and the induction motor in the AMB rotor system.</jats:p