An Energy-efficient Switching Scheme with Reduced Switching Transients for a Wind-driven Induction Generator

This article presents a scheme for improving the power output of grid-connected induction generator commonly used in wind energy conversion systems. Generally, the stator of the induction generator is connected in a star with a line voltage of √3 times the rated winding voltage to reduce the line current and, hence, conductor size. To extend the generating operation over a wider speed range, delta-star switchable stator windings are also in vogue. In such cases, the stator is star connected in the lower speed range and switched to a delta connection above a threshold speed. In this study, a new switching scheme is proposed wherein the stator coils are always connected in a star, while the stator is connected to different voltages in low- and high-speed conditions. At low wind speeds, nominal winding voltage is applied to the stator, whereas at higher speeds, the stator applied voltage is √3 times higher than the rated winding voltage. The efficacy of the scheme is demonstrated experimentally with a suitable microcontroller-based switching arrangement. Typical results indicate an increase in output with reduced switching transients. A case study on a 3-Φ, 50-kW induction generator is presented to emphasize the performance improvement with the proposed scheme.     

Multi-electron systems in strong magnetic fields II: A fixed-phase diffusion quantum Monte Carlo application based on trial functions from a Hartree–Fock–Roothaan method

We present a quantum Monte Carlo application for the computation of energy eigenvalues for atoms and ions in strong magnetic fields. The required guiding wave functions are obtained with the Hartree–Fock–Roothaan code described in the accompanying publication (Schimeczek and Wunner, 2014). Our method yields highly accurate results for the binding energies of symmetry subspace ground states and at the same time provides a means for quantifying the quality of the results obtained with the above-mentioned Hartree–Fock–Roothaan method.     

Hierarchical Implicit Shape Modeling

In this paper, a new hierarchical approach for object detection is proposed. Object detection methods based on Implicit Shape Model (ISM) efficiently handle deformable objects, occlusions and clutters. The structure of each object in ISM is defined by a spring like graph. We introduce hierarchical ISM in which structure of each object is defined by a hierarchical star graph. Hierarchical ISM has two layers. In the first layer, a set of local ISMs are used to model object parts. In the second layer, structure of parts with respect to the object center is modeled by global ISM. In the proposed approach, the obtained parts for each object category have high discriminative ability. Therefore, our approach does not require a verification stage. We applied the proposed approach to some datasets and compared the performance of our algorithm to comparable methods. The results show that our method has a superior performance.     

商务智能在电网调度控制系统数据分析中的应用

为了准确定位电网调度控制运行的异常信息,需要从电网调度控制系统的大量历史信息中获取关键信息,文中从商务智能(BI)的角度提出了海量数据统计分析的解决方案。首先阐述了BI的概念及在电网调度控制系统中推广应用困难的原因,接着介绍了BI整合到电网调度控制系统中所必备的核心软件模块,最后结合智能电网调度控制系统(简称"D5000系统")的调控业务,以实例展示如何将BI融合到D5000系统中。     

基于千兆网接口的星敏感器图像显示与存储

为了提高星敏感器地检设备中图像采集的便携型,设计了基于千兆网接口的星敏感器图像显示与存储系统。系统硬件平台包括输入图像解码与输出图像编码两部分,以AX88180和M88E1111为关键器件,在FPGA的控制下完成CameraLink图像到千兆网图像的协议转换,上位机软件通过Socket和多线程技术采集实时原始图像。通过实际应用证明,该系统满足图像数据的传输速度要求,能够方便地实现星敏感器图像的显示与存储。     

基于PSF参考模型的星敏感器单粒子效应在轨校正方法

为了提高星敏感器在遭受单粒子效应打击情况下的质心提取精度,提出了一种基于点扩散函数参考模型的在轨校正方法。通过构建星点参考模型及残差校正,该方法能有效去除单粒子噪声,校正噪声星点形态,降低星点质心定位误差。与传统去噪算法相比,该方法能在有效去噪的同时保护星点能量不被破坏。通过仿真实验验证了该算法抗单粒子效应的有效性,通过对比实验验证了该算法相比传统算法的优越性。     

星型光通信模块的组网方案研究与设计

本文结合"铁路车站全电子化应急联锁系统"的研发,将该系统联锁通信单元与执行通信单元之间的通信方式由电缆改为光纤,提出并行星型耦合器组网方案,设计出能插入在室内执行机柜内的星型光通信模块实现联锁通信单元与执行通信单元之间的光通信;通过光电转换电路,隔断联锁通信机与执行机智能电子模块之间通信电路的电联系,给出了通信模块的硬件与软件实现.通过电磁兼容测试实验证明,该组网方案具有可靠性高、成本低、易升级等优点.     

星形聚合物的发展近况

综述了采用负离子聚合技术合成的星形聚合物的结构与性能的关系、合成路线及应用。新开发的星形聚合物,如ＳＳＢＲ,ＬＣＢＲ,ＭＶＢＲ,ＨＶＢＲ,ＳＩＢＲ等,运用高分子分子设计的方法来合成,因而具有更佳的综合性能,如高的抗湿滑性及低的滚动阻力等。     

基于硅基液晶拼接的高对比度动态星模拟器光学系统

针对基于硅基液晶(LCOS)拼接技术的动态星模拟器对比度低,无法在星图识别过程中为星敏感器提供全部有效目标的问题,提出通过抑制光学系统杂散光来提高LCOS拼接动态星模拟器对比度的方法,讨论了偏振度对于杂散光的影响,并推导出入射角与偏振度的函数关系。设计了抑制杂散光的光学系统,该系统包括利用复合抛物面聚光器(CPC)结合望远系统组成照明光源,配合多棱镜的1/4波片和视场角不小于11°的准直光学系统。在截止频率为60lp/mm,视场角小于±5°的情况下,该准直系统的调制传递函数(MTF)大于0.7。实验显示:该高对比度LCOS拼接动态星模拟器的星间角距误差小于18″,相对于传统型的星模拟器杂散光降低了2.38倍,其在保证精度的条件下,降低了动态星模拟器的背景噪声,提高了动态星图的可识别率,基本可以满足星敏感器在多星等条件下的对精度和动态特性的需求。     

膜计算优化PID控制在煤炭分拣机器人中的应用

在传统煤炭分拣机器人的分拣过程中,由于时变负载的非线性变化经常引起速度的波动,严重影响了系统的控制性能,降低了机械手操作的精确性和快速性。论文设计了一种基于模糊星形拓扑结构的膜计算优化算法(FST-MC算法)优化的PID自整定系统,将PID的三个控制参数编码成FST-MC算法优化的对象,经过换位、交流、交叉和改写这四个规则处理后得到理想的优化值。最后,进行了仿真实验,实验结果验证了本系统响应速度快、有着很好的动态跟随性能和很高的控制精度,在煤炭分拣机器人系统中有着很好的应用前景。