基于StruxureWare的船舶电网监测系统

为了维护船舶电力系统的稳定性,监测船舶电网重要的相关参数,分析船舶电力系统的电能质量,基于施耐德StruxureWare电能管理系统搭建了一套船舶电网电能质量监测与分析的系统。系统设计了电能质量监测界面,谐波分析界面以及远程监视界面,故障报警界面。在船舶电站实验室环境下模拟了不同工况下的船舶电网,分析了不同工况下船舶电网中谐波的含量,实时的监测船舶电网中电能质量的相关参数,以及提供了故障录波以及故障报警。为解决故障提供分析基础,提高了船舶电网电能质量管理能力。     

直流微电网储能系统双向DC-DC控制器硬件电路设计

针对直流微电网进行能量双向变换时母线电压不稳定问题,对用于直流微电网储能系统中双向DC-DC变换器的硬件电路进行研究与设计。详细介绍了双向DC-DC变换器的工作原理及硬件电路构成,并对硬件电路主要元器件的选型进行了说明。为实现实际电路中系统母线电压产生波动时能迅速恢复到正常工作电压状态,制作了实物并进行测验。实验结果表明,通过合理的双向DC-DC变换器硬件电路设计不仅可实现能量的双向传递,且在系统母线电压波动时,实现DC-DC变换器精确控制可确保直流母线电压稳定,提高直流微电网储能系统的可靠性。     

LNG发电船微电网的能量管理系统研究

LNG发电船是一种使用液化天然气作为清洁能源的可移动式独立微电网,在港口使用LNG发电船作为辅助电源,可以大幅降低港口排放。考虑到LNG发电机组的单机最大容量的限制,设计了一种配置了功率补偿装置的微电网单元,可以根据实际需求进行并联扩容,并有效解决了LNG发电机组负载动态响应的不足。为保证该系统的稳定性以及发电质量的可靠性,建立了一套分层架构的分布式能量管理系统,该系统既具备自主性,又能保持系统的协作性及可扩展性。     

岷江犍为航电枢纽二期围堰施工通航水流条件研究

岷江犍为航电枢纽是岷江港航电综合开发建设任务规划中至关重要的一环,而岷江作为四川大件运输的重要通道,其水上运输意义重大。为保障施工期岷江航道畅通,特别是施工期导流中的二期围堰阶段,采取临时航道通航,对航道布置及航路调整较大。通过水工模型试验及船模试验测定水流流速、流态及船舶航行姿态等相关参数。结果表明,原设计方案在枯水期存在进口处水深不足、在大流量下纵向围堰堤头出现绕流流态的问题,对船舶航行极为不利。根据试验结果提出相应的优化措施,优化后基本消除或改善了上游进口处枯水期碍航及中洪水期围堰堤头绕流流态,使设计航道中游段流速分布整体更为均匀,改善了通航条件,为同类枢纽施工围堰通航提供参考。     

A hybrid dead reckoning error correction scheme based on extended Kalman filter and map matching for vehicle self-localization

In this research, a hybrid dead reckoning error correction scheme is developed based on extended Kalman filter (EKF) and map matching (MM) to improve the positioning accuracy for vehicle self-localization. The developed method aims at obtaining accurate positions when the GPS signals are occasionally unavailable or weakened. First, the heading data collected from an odometer and an optical fiber gyroscope are integrated by an EKF to reduce the random errors in dead reckoning. Then a modified topological MM algorithm is developed to reduce the systematic errors in dead reckoning. In this work, both cross-track errors and along-track errors are considered to improve positioning accuracy of MM. The errors are finally corrected using the results achieved from both the dead reckoning and the MM when the driving distance of a vehicle exceeds a predefined length or the vehicle turns in an intersection. Experiments have been conducted to evaluate the developed method and the results show that the maximum error and average error of dead reckoning can be respectively reduced to 15.4?m and 5.2?m during the experiment with total distance of 43?km. This positioning accuracy is even better than the accuracy of the low-cost GPSs which are usually at the order of 15–20?m (95%). The developed method is effective to achieve the positions of the vehicle when the GPS signals are occasionally unavailable or weakened.     

Effect of modified supplementary cementitious material on performance of mortar and concrete in marine environment

This study aims to explore the durability issues regarding chloride ion corrosion of concrete structures, and further investigates the modified supplementary cementitious material (MSCM) which acts as a significant enhancer of performance of mortar and concrete. The composition of MSCM includes mineral slag powder, fly ash and inhibitor. The microstructure, sulfate erosion resistance and electric flux of high-performance concrete are tested with MSCM, and the results show that the pore structure of concrete is improved significantly along with excellent electrochemical performance. It is observed that the substantiality of concrete after being mixed with 18% (mass fraction) MSCM is enhanced effectively. The sulfate resistance coefficient of concrete is found to be greater than 1.2, and the electric flux of concrete is less than 600C. These results have demonstrated that the MSCM possesses an excellent electrochemical performance and a wide applicative prospect in marine environment.     

轿车声固耦合低频噪声的有限元分析

建立结构载荷激励下乘坐室空腔声学系统和声固耦合系统的有限元模型。利用有限元软件ANSYS和LMS V irtual.lab对某轿车乘坐室结构与空腔声模态的频率和振型进行分析,采用直接法和模态叠加法对该轿车车内噪声仿真结果进行比较,指出采用模态叠加法计算声固耦合问题时,对于结构模态阶数的提取要求。通过计算仿真分析该模型低频噪声在频域中的分布情况,为降低由结构振动引起的车内低频噪声提供结构修改和声学修改依据。     

驾驶员反应时间研究

对于预警类智能辅助驾驶系统,驾驶员的反应时间是一个重要参数。本文针对不同的驾驶员类型、不同的预警方式,在实车测试平台上进行驾驶员反应时间的测量。通过实验可以得出各种情况下不同的驾驶员反应时间,该研究的成果将对预警类智能辅助驾驶系统中预警方式和预警时间的选取起到积极的作用。     

美国海军先进阻拦装置发展情况研究

先进阻拦装置是美国为建造"福特"级航母而专门研发的新一代航母阻拦装置.该装置以水涡轮机、感应电机以及机械制动器为主要吸能部件,具有阻拦能级高、阻拦过载小等性能优势.本文首先简要介绍了美国先进阻拦装置的发展历程,并对先进阻拦装置的工作原理、系统组成以及技术方案进行了详细剖析,总结了主要技术难点.在此基础上,梳理并分析了先...     

石灰改性黄土的强度特性试验研究

结合兰(州)武(威南)铁路二线建设,对石灰改性黄土进行了强度特性、抗冻融特性等试验分析研究,得出了石灰改性黄土的强度随养护龄期的增长而增大;而掺合比的影响并不是单一的比例关系,存在一个最佳石灰掺合比;石灰黄土的水稳定性可以得到很好的改善.最后探讨了石灰改性黄土的抗冻融特性,得出其抗冻融能力较差,这对石灰改性黄土的实际工程应用起到重要的参考作用.