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排序方式: 共有772条查询结果,搜索用时 78 毫秒
41.
A method to determine direct‐ and quadrature‐axis inductances of permanent magnet synchronous motors
Shu Yamamoto Takashi Kano Yoshihiro Yamaguchi Takahiro Ara 《Electrical Engineering in Japan》2010,171(3):41-50
The equivalent circuit constants of permanent magnet synchronous motors are needed in the calculation of operation characteristics, construction of a control system, etc. These constants can be computed from the data on structural form and materials. However, measurements are necessary to obtain highly precise values. Methods for measurement of the d‐ and q‐axis inductances can be roughly divided into rotational and standstill methods. The standstill methods have the advantage that they are easy to carry out. However, it is difficult to consider magnetic saturation and distortion of the change in the armature winding inductance. The accuracy of the standstill method can be improved if these effects can be readily taken into account. This paper describes a standstill method for measuring accurate d‐ and q‐axis synchronous inductances of permanent magnet synchronous motors. By utilizing the fact that the EMF interference terms in the motor voltage equation considering the distortion of the inductance change are equal to zero when the rotor is in a specific position, the proposed method determines the inductances considering both magnetic saturation and inductance distortion effects from simple off‐line standstill testing. In addition, this method is capable of taking cross‐magnetic saturation into account when used with the necessary testing equipment. The proposed method was implemented on a 0.4‐kW interior permanent magnet synchronous motor with concentrated stator winding. The validity of the proposed method was demonstrated by comparing the measured and calculated results of the no‐load and on‐load characteristics. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 171(3): 41–50, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20969 相似文献
42.
João C. Santos Madalena M. DiasAlírio E. Rodrigues 《Computers & Chemical Engineering》2011,35(7):1186-1191
The ideal adsorbed solution theory (IAS) is commonly used in process simulation for predicting multicomponent adsorption equilibrium. However, this model requires a significant computational effort which translates in time consuming simulations.A methodology using surface B-splines fitting was developed for speeding the prediction of the multicomponent equilibrium with IAS theory. As a case study, a breakthrough of an enantiomer bi-component mixture in a fixed bed was simulated and a speed-up of 57.9% was achieved while maintaining the accuracy of IAS multicomponent equilibrium prediction. 相似文献
43.
Sustainability metrics for eco-technologies assessment, Part II. Life cycle analysis 总被引:1,自引:1,他引:0
Juliana Garcia Moretz-Sohn Monteiro Ofélia de Queiroz Fernandes Araújo José Luiz de Medeiros 《Clean Technologies and Environmental Policy》2009,11(4):459-472
This work presents a sustainability analysis of CO2 reuse to produce dimethyl carbonate (DMC) via ethylene oxide (ROUTE A) and via urea methanolysis (ROUTE B). Two different
technologies are considered in ROUTE A: reaction followed by separation and reactive distillation. Life cycle analyses of
the ROUTES are presented employing sustainability analysis performed in HYSYS process simulator, along with WAR Algorithm.
Process economical optimization is performed to maximize the processes profitability. A sustainability function, defined as
a 2D indicator involving both economical and environmental aspects, is calculated for the optimized processes. Additional
sustainability indexes are evaluated: material index, energy index, and ecoefficiency. The results, under both economical
and environmental aspects, show that ROUTE A is the most sustainable. The study also points to the relevance of the frontier
set between the domains cradle-to-gate and gate-to-gate in assessing process sustainability during LCA. 相似文献
44.
In this Letter, a new approach to build a neural model for the fast identification of spatiotemporal sequences is proposed. Such a model, the Stochastic Neural Sequence Identifier (SNSI), is simple and rapidly learns and identifies a given sequence. The SNSI receives as input several patterns belonging to a particular spatiotemporal sequence and produces as output a label for the sequence identified and a probability of this classification being correct. The SNSI is able to identify a sequence from patterns learned during training or novel ones, i.e., combinations of the sequence items distinct from those belonging to the trained set. The SNSI was tested on a 2D set of both closed and open trajectories with varying levels of complexity. The results suggest that the SNSI is able to recognize all the patterns presented in the training and most of the novel patterns used for testing. 相似文献
45.
R. A. C. Santana S. Prasad A. R. N. Campos F. O. Araújo G. P. da Silva P. de Lima-Neto 《Journal of Applied Electrochemistry》2006,36(1):105-113
Electrodeposition of Ni–W–B alloys from plating baths containing ammonia and citrate is reported. Optimum conditions for plating
including current density, temperature, mechanical agitation and pH were studied. The corrosion resistance and amorphous character
were also evaluated. The operational conditions for depositing the alloy with good corrosion resistance were: current density
35 mA cm−2, bath temperature 40 °C, pH 9.0 and cathode rotation at 90 rpm. The alloy was deposited at 38% current efficiency, with an
average composition of 73 wt% Ni, 27 wt% W and traces of boron and with E
corr −0.300 V and R
p 3.369×104 Ω. The deposit obtained under these conditions had an amorphous character with the presence of some microcracks on its surface
reaching down to the copper substrate. Electrochemical corrosion tests verified that the Ni–W–B alloy had better corrosion
resistance than Co–W–B. 相似文献
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50.
Pankaj Agrawal Silvia I. Oliveira E. M. Araújo Tomas J. A. Melo 《Journal of Materials Science》2007,42(13):5007-5012
In this work, the rheological, mechanical and morphological properties of nylon 6/polypropylene compatibilized blends were
investigated. Two types of polypropylene were used. One with MFI of 40 g/10 min (PP H103) and the other with MFI of 3.5 g/10 min
(PP H503). The compatibilizers used were polypropylene grafted with 6% of acrylic acid (PPgAA) and polypropylene grafted with
1% of maleic anhydride (PPgMA). The blends composition was 80/20 (wt%) for the PA6/PP binary blends and 80/10/10(wt%) for
the nylon 6/PPgAA/polypropylene and nylon 6/PPgMA/polypropylene ternary blends. Torque rheometry analysis showed that when
PPgAA and PPgMA were added to nylon 6/polypropylene blends, there was an increase in the torque, indicating that reactive
compatibilization has occurred. There is no influence of the polypropylene MFI on the mechanical properties of the uncompatibilized
and compatibilized blends. The impact strength of the blends containing PPgMA were greater than those of the blends containing
PPgAA. The blends containing PPgAA are unstable. SEM analysis showed that PPgMA improves considerably the adhesion between
PA6/PP phases, leading to good mechanical properties. 相似文献