关于“电力电子技术”课程教学改革的实践探索

文章从课程标准的制定、实训室的建设、配套教材的编写、课程教学方法和组织形式的创新等方面,阐述了"电力电子技术"课程教学改革实践中的具体做法,以实现理论教学与实践教学的交融渐进。     

Design of offshore structures against accidental ship collisions

In this paper, we investigate the damage to offshore platforms subjected to ship collisions. The considered scenarios are bow and stern impacts against the column of a floating platform and against the jacket legs and braces. The effect of the ship–platform interaction on the distribution of damage is studied by modeling both structures using nonlinear shell finite elements. A supply vessel of 7500-ton displacement with bulbous bow is modeled. A comprehensive numerical analysis program is conducted, and the primary findings are described herein. The collision forces from the vessel are compared with the suggested force–deformation curves in the NORSOK code. For collisions with floating platforms we particularly focus on the crushing behavior and potential penetration of the bulbous bow and stern sections into the cargo tanks or void spaces of semi-submersible platforms. For fixed jacket platforms we investigate whether jacket braces can penetrate into the ship without being subjected to significant plastic bending or local denting.Adequate treatment of the relative strength between the interacting bodies is especially relevant for impacts with high levels of available kinetic energy, for which shared energy or strength design is aimed at. Simplifying one body as rigid quickly leads to overly conservative and/or costly solutions, and is in some cases non-conservative.The numerical analysis is used to develop a novel pressure–area relation for the deformation of the bulbous bow and stern corners of the supply vessel. Procedures for strength design of the stiffened panels are discussed. Refined methods and criteria are proposed for strength design of platforms, including both floating and jacket structures. The adequacy of the NORSOK design guidance for collisions against jacket legs is evaluated. The characteristic strength of a cylindrical column is used to develop a novel criterion for the resistance to local denting from stern corners and bulbous bows.     

民用船舶直流电网发展现状分析

随着世界传统化石能源的日益枯竭,石油价格节节攀升以及电力系统电子技术的发展,船舶行业越来越关注直流电力系统在船舶上的应用。目前已有企业凭借自己的技术优势率先开发了新型直流电网的船舶,并投入了应用。本文对船舶电力系统采用新技术的优缺点及应用情况进行分析,提出当前需要解决几个问题。     

用于船舶电站控制器的交流采样算法研究

对交流采样算法的分析表明,离散傅立叶算法不能算出频率,在非整周期同步采样时误差较大。非同步算法中的加窗插值算法通过加窗插值减小频谱泄漏,不需整周期同步采样,可直接计算频率,对船舶电站采样具有很好的适应性。该算法多针对谐波分析,当用于船舶电站,只计算基波参数时,需选择合理采样方案。通过对算法的分析与推导,选择合理采样方案,在满足精度要求的同时使计算量适中,并应用于船舶电站控制器,很好地满足采样要求。     

某重型汽车动力性与燃油经济性仿真与匹配优化

根据某重型汽车的结构参数,按照动力传递路线,利用GT-DRIVE软件对该重型汽车进行了建模仿真,并分析了其动力性和燃油经济性。仿真结果与试验结果的对比验证了该整车模型的正确性。将此模型导入modeFRONTIER优化软件,采用多目标遗传算法对该车的传动系统参数进行优化,从优化方案中选取几种方案进行比较分析,并根据实际使用的需要确定了该车动力传动系统的最佳匹配方案。     

公交可达性水平分析方法在城市静态交通规划中的应用

近年来我国大城市机动车保有量增长迅速,城市交通面临严峻考验,动静态交通之问的矛盾以及“停车难”等问题日益突出,但一直以来静态交通规划均以满足停车需求为主,缺乏考虑与公共交通等方面的联系.本文对公交可达性水平分析方法在城市静态交通规划中的应用进行了具体介绍,该方法将静态交通和动态交通、公共交通和个体交通、交通设施和交通管...     

电动汽车EPS助力工况柔性PID控制及试验

建立了汽车3自由度转向模型和EPS动力学模型,设计了助力工况的无缝车速助力模式和柔性PID控制器.柔性PID控制器可根据控制误差大小,判断系统误差所在的运行状态,实时调整控制器结构和控制参数.分别在车速为20 km/h、30 km/h和40 km/h情况下进行蛇行仿真和实车试验结果表明,柔性PID控制与无控制和原车控制...     

“新海旭”全球最大非自航重型绞吸挖泥船

本论文介绍了国内自2010年以来建成的四型有代表意义的非自航大型绞吸挖泥船和国外最大的两艘非自航绞吸挖泥船,可以看到国内自主研制能力已经步入国际领先行列。集成船舶设计通用原理和绞吸挖泥船专业疏浚设备开发技术,用图形的方式表示了该船型设计的主要方面。扼要介绍了“新海旭”的总布置、航区、动力配置、疏浚输送系统和钢桩台车定位系统等,并对大型绞吸挖泥船的作业航区、动力配置方案和疏浚输送系统生产能力等进行了探讨和分析。论文提出的绞吸挖泥船设计原理和对“新海旭”的技术状态介绍可供开发大型绞吸挖泥船参考。     

摩托车噪声源的识别与控制

通过声强测试技术和加速噪声的模拟试验对摩托车的主要噪声源进行了识别研究,结果表明进、排气噪声是摩托车的主要噪声源,并初步确定了进、排气噪声对整车加速噪声的贡献量。利用边界元计算(BEM)技术对空气滤清器和排气消声器的声学性能进行仿真分析和改进设计。新设计的空气滤清器和排气消声器对整车的通过噪声有2.7dB的降噪效果。