scholarly journals Modelling Thomson Coils With Axis-Symmetric Problems: Practical Accuracy Considerations

2017 ◽  
Vol 32 (2) ◽  
pp. 629-639 ◽  
Author(s):  
Damian Sergio Vilchis-Rodriguez ◽  
Roger Shuttleworth ◽  
Mike Barnes
Keyword(s):  
Author(s):  
K. Nakano ◽  
Y. Tanaka ◽  
H. Suzuki ◽  
K. Hayakawa ◽  
M. Kurodai

Abstract. Unmanned aerial vehicles (UAVs) equipped with image sensors, which have been widely used in various fields such as construction, agriculture, and disaster management, can obtain images at the millimeter to decimeter scale. Useful tools that produce realistic surface models using 3D reconstruction software based on computer vision technologies are generally used to produce datasets from acquired images using UAVs. However, it is difficult to obtain the feature points from surfaces with limited texture, such as new asphalt or concrete, or detect the ground in areas such as forests, which are commonly concealed by vegetation. A promising method to address such issues is the use of UAV-equipped laser scanners. Recently, low and high performance products that use direct georeferencing devices integrated with laser scanners have been available. Moreover, there have been numerous reports regarding the various applications of UAVs equipped with laser scanners; however, these reports only discuss UAVs as measuring devices. Therefore, to understand the functioning of UAVs equipped with laser scanners, we investigated the theoretical accuracy of the survey grade laser scanner unit from the viewpoint of photogrammetry. We evaluated the performance of the VUX-1HA laser scanner equipped on a Skymatix X-LS1 UAV at a construction site. We presented the theoretical values obtained using the observation equations and results of the accuracy aspects of the acquired data in terms of height.


Author(s):  
Helmut Benigni ◽  
Stefan Leithner ◽  
Helmut Jaberg ◽  
Mark Guggenberger

Abstract Turbines or pumps in hydropower plants achieve peak efficiencies of far more than 90% depending on the specific speed and the type of machine. Based on model tests or numerical simulations, the efficiency of a prototype machine has to be guaranteed and measured with the best measurement technique available. The choice of the appropriate efficiency measurement method does not only depend on the expected measurement uncertainties and tolerances set in a contract, it is also a question of the effort required for such a measuring campaign and of technical challenges, e.g., limitations imposed by plant operating conditions as draining of the system or constant load operation. Concerning hydraulic turbomachines, modern measuring technology offers different methods for efficiency measurements at a turbine unit. Primarily through the development of real-time capable data acquisition systems, it is possible to perform high-precision measurements rather quickly, whereby minimal downtimes can be achieved. In the first part, the specific measurement methods available in different standards are presented in an overview, and then in the second part, the achieved accuracies of a very complex thermodynamic measurement are compared with a low-cost clamp-on acoustic Doppler measurement using a concrete example.


1997 ◽  
Author(s):  
Alan P. Pritchard ◽  
Mark A. Venables ◽  
Stephen P. Lake ◽  
David W. Gough

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4824
Author(s):  
Fabio Mandrile ◽  
Salvatore Musumeci ◽  
Enrico Carpaneto ◽  
Radu Bojoi ◽  
Tomislav Dragičević ◽  
...  

In modern power electronics-based power systems, accurate modeling is necessary in order to analyze stability and the interaction between the different elements, which are connected to it. State space modeling seems a valid approach to study the modes of a certain system and their correlation with its states. Unfortunately, this approach may require complicated calculations and it is difficult to model advanced or emerging control techniques for grid-tied converters, such as cascaded controllers (e.g., voltage and current) and virtual synchronous generators (VSGs). Moreover, this approach does not allow an easy reconfiguration of the modeled system by adding, removing of modifying certain elements. To solve such problems, this paper presents a step-by-step approach to the converter modeling based on the Component Connection Method (CCM). The CCM is explained in detail and a practical example is given, by modeling one exemplary VSG model available in the literature. The obtained model is finally validated experimentally to demonstrate the practical accuracy of such approach.


2020 ◽  
Vol 29 (4) ◽  
pp. 1-35 ◽  
Author(s):  
Junjie Chen ◽  
Zhuo Wu ◽  
Zan Wang ◽  
Hanmo You ◽  
Lingming Zhang ◽  
...  

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