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51.
This paper deals with an advanced static Var compensator (ASVC) using quad-series voltage-source PAM inverters. The ASVC consists of four three-phase voltage-source inverters with a common dc capacitor and four three-phase transformers, each primary winding of which is connected in series with each other. Each inverter outputs a square-wave voltage, while the synthesized output voltage of the ASVC has a 24-step wave shape. This results not only in a great reduction of harmonic currents and dc voltage ripples but also in fewer switching and snubbing losses. In this paper, transient analysis is performed with the focus on the response of reactive power and the resonance between the dc capacitor and ac reactors. Experimental results obtained from a small-rated laboratory model of 10 kVA are also shown to verify analytical results based on the p-q transformation. The analytical results help in the design of system parameters such as the capacity of the dc capacitor and feedback gains. 相似文献
52.
离散事件动态系统的代数模型及其控制器的分析计算 总被引:4,自引:2,他引:2
本文在离散事件动态系统的Petri网图形描述的基础上建立了相应的代数模型,该模型可以用来计算无竞争无回路Petri网的“最大状态”;该“最大状态”的计算在本文给出的动态反馈控制器中得到了应用。 相似文献
53.
采用锁相技术,对电子束曝光机工件台运动实现速度环的全数字控制。设计了数字差频积分回路和数字差频比例控制器,能有效消除速度的静态误差和改善系统的动态特性。 相似文献
54.
E. L. Shanina G. E. Zaikov L. K. Fazlieva S. V. Bukharov N. A. Mukmeneva 《应用聚合物科学杂志》2002,85(10):2239-2243
The influence of sulphur‐ and phosphorum‐containing substances (hydroperoxide decomposers) on the kinetics of the consumption of two phenolic antioxidants in polypropylene (PP) was studied. The induction periods of PP autoxidation at 130°C were measured in the presence of inhibiting compositions that consisted of phenolic inhibitors and decomposers of hydroperoxide. Obtained results indicated that the influence of the hydroperoxide decomposer became significant when the concentration of the phenolic antioxidant became close to critical value. It also was shown that the efficiency of the hydroperoxide decomposer significantly depended on the mechanism of the transformation of the phenolic inhibitor; and first of all on the nature of its transformation products. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2239–2243, 2002 相似文献
55.
Tucker Don M.; Luu Phan; Frishkoff Gwen; Quiring Jason; Poulsen Catherine 《Canadian Metallurgical Quarterly》2003,112(4):667
Functional neuroimaging suggests that limbic regions of the medial frontal cortex may be abnormally active in individuals with depression. These regions, including the anterior cingulate cortex, are engaged in both action regulation, such as monitoring errors and conflict, and affect regulation, such as responding to pain. The authors examined whether clinically depressed subjects would show abnormal sensitivity of frontolimbic networks as they evaluated negative feedback. Depressed subjects and matched control subjects performed a video game in the laboratory as a 256-channel EEG was recorded. Speed of performance on each trial was graded with a feedback signal of A, C, or F. By 350 ms after the feedback signal, depressed subjects showed a larger medial frontal negativity for all feedback compared with control subjects with a particularly striking response to the F grade. This response was strongest for moderately depressed subjects and was attenuated for subjects who were more severely depressed. Localization analyses suggested that negative feedback engaged sources in the anterior cingulate and insular cortices. These results suggest that moderate depression may sensitize limbic networks to respond strongly to aversive events. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
56.
F. L. Lewis 《Journal of Intelligent and Robotic Systems》2007,48(4):513-523
This is an outline of research in neural networks for feedback control done since the mid 1990s at the Automation and Robotics
Research Institute (ARRI) of The University of Texas at Arlington (UTA). It shows how the developments of Intelligent Control
Systems based on neural networks have followed three main generations. This statement provides a short, broad-brush perspective
on the development of intelligent neural feedback controllers. 相似文献
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Although increasing feedback specificity is generally beneficial for immediate performance, it can undermine certain aspects of the learning needed for later, more independent performance. The results of the present transfer experiment demonstrate that the effects of increasing feedback specificity on learning depended on what was to be learned, and these effects were partially mediated through the opportunities to learn how to respond to different task conditions during practice. More specific feedback was beneficial for learning how to respond to good performance and detrimental for learning how to respond to poor performance. The former relationship was partially mediated by feedback specificity's effect on learning opportunities during practice. The results have implications for designing feedback interventions and training to maximize the learning of various aspects of a task. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
60.
The authors examined whether participants can shift their criterion for recognition decisions in response to the probability that an item was previously studied. Participants in 3 experiments were given recognition tests in which the probability that an item was studied was correlated with its location during the test. Results from all 3 experiments indicated that participants' response criteria were sensitive to the probability that an item was previously studied and that shifts in criterion were robust. In addition, awareness of the bases for criterion shifts and feedback on performance were key factors contributing to the observed shifts in decision criteria. These data suggest that decision processes can operate in a dynamic fashion, shifting from item to item. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献