Analytical approach and solution for start-up behavior of line-start permanent magnet synchronous machines (LSPSM)
This paper presents a derivation for the maximum transient current and torque peak values for small non-salient line starting permanent magnet synchronous machine (LSPSM) on base of permissible approximations. First the equations for locked rotor operation and secondly for constant speed operation are deduced. This paper is focused on derivation of the analytical calculation process to get an approach for transient current and torque. Saturation and speed dependency of parameters are not considered. With the derived equations, effects of parameters on the peak values of torque and current at starting can be shown.
Analysis of the effects of parameter variations on the start-up characteristics of LSPMSM
Based on the numerical solution, this paper describes the analysis of the impact of rotor anisotropy and moment of inertia on the synchronization capability of Line Starting Permanent Magnet Synchronous Machines (LSPMSM). Coming from an induction motor the studies reveal an effect that is not known from the theory of the induction motors. In addition to start-up, synchronization is a key development aspect. This paper examines the synchronization process and reveals its constraints. It also shows the influence of the so-called “Goerges”-phenomenon on speed and torque during start-up. The aim of the work is to improve the knowledge and prediction of the characteristics and properties of this type of machine.
Unidirectional hexagonal rare-earth disilicide nanowires on vicinal Si(100)-2×1
Rare-earth disilicide nanowires grown on vicinal Si(100) with a miscut of 2–2.5° toward the [110] azimuth at 600 °C were studied by scanning tunneling microscopy and compared with those grown on flat Si(001). In contrast to rare-earth disilicide nanowires grown on flat Si(100) surfaces, the nanowires grow unidirectionally along the [01̄1] direction of the vicinal Si(100) surface. Rare-earth disilicide nanowires form bundles composed of single nanowire units on both flat and vicinal surfaces. Yet, on the vicinal surface, the bundle width is comparable to the width of the terrace. The average nanowire length on the vicinal substrate is longer than that on the flat substrate. Scanning tunneling spectroscopy shows that the rare-earth disilicide nanowires have metallic properties.