Rare-earth Magnet Free Flux-switching Generator for Wind Turbines in Micro-grids:A Review

In traditional electricity generation plants,large powerful synchronous,induction,and direct current generators were used.With the proliferation of microgrids focused on electricity generation from renewable energy sources in today’s power grids,studies have been conducted on different types of generators.Instead of the traditional generator architecture,generators with brushless structures,particularly those utilizing magnets for excitation,have found broad applications.Fluxswitching generators(FSGs)are innovative types owing to their robust structure,active stator design,and high power density capabilities.However,designs have typically relied on rare-earth element magnets.Rare-earth magnets possess negative characteristics such as price uncertainty,the potential risk of scarcity in the future,and limited geographical production,leading to research on FSGs that do not depend on rare-earth magnets.This study comprehensively examines FSGs that do not use rare-earth element magnets.The study delves into the usage areas,operational mechanisms,structural diversities,and counterparts in the literature of these generators.

Distributed Economic MPC for Synergetic Regulation of the Voltage of an Island DC Micro-Grid

In this paper,distributed model predictive control(DMPC) for island DC micro-grids(MG) with wind/photovoltaic(PV)/battery power is proposed,which coordinates all distributed generations(DG) to stabilize the bus voltage together with the insurance of having computational efficiency under a real-time requirement.Based on the feedback of the bus voltage,the deviation of the current is dispatched to each DG according to cost over the prediction horizon.Moreover,to avoid the excessive fluctuation of the battery power,both the discharge-charge switching times and costs are considered in the model predictive control(MPC) optimization problems.A Lyapunov constraint with a time-varying steady-state is designed in each local MPC to guarantee the stabilization of the entire system.The voltage stabilization of the MG is achieved by this strategy with the cooperation of DGs.The numeric results of applying the proposed method to a MG of the Shanghai Power Supply Company shows the effectiveness of the distributed economic MPC.

Development of Smart Micro-grid Energy Efficiency Technologies on Workplace Level

The objective of this paper was to understand the increasing importance of building energy consumption, an overview of the comfort needs of the occupants is first deemed necessary in new control strategy for automatic control and to present facts that characterize the energy consumption, most particularly at the workplaces level with new technology strategies. The study’s methodology applies functional and hierarchical separation. The contributions of this paper are static and dynamic models of individual users in a proposed existing building to create an office environment. To fulfill the purpose of the study and the research the following research questions will be investigated and analyzed from an architect’s perspective: (1) Are there appropriate technologies for improving energy efficiency in new buildings from the point of view the micro-grid, control and evaluation process in strategy? (2) Which sensor technology can determine the zone that needs or needs not to be considered the comfort?

Power-Sharing Enhancement Using Harmonized Membership Fuzzy Logic Droop Control Based Micro-Grid

The contribution of Renewable Energy Resources(RER)in the process of power generation is significantly high in the recent days since it paves the way for overcoming the issues like serious energy crisis and natural contamination.This paper deals with the renewable energy based micro-grid as it is regarded as the apt solution for integrating the RER with the electrical frameworks.As thefixed droop coefficients in conventional droop control approaches have caused various limitations like low power-sharing and sudden drops of grid voltage in the Direct Current(DC)side,the Harmonized Membership Fuzzy Logic(MFL)droop control is employed in this present study.This proposed droop control for the hybrid PV-wind-battery system with MFL assists in achieving proper power-sharing and minimizing Total Harmonic Distortion(THD)in the emer-gency micro-grid.It eradicates the deviations in voltage and frequency with itsflexible and robust operation.The THD is reduced and attains the value of 3.1%compared to the traditional droop control.The simulation results of harmo-nized MFL droop control are analogized with the conventional approaches to vali-date the performance of the proposed method.In addition,the experimental results provided by the Field Programmable Gate Array(FPGA)based laboratory setup built using a solar photovoltaic(PV)and wind Permanent Magnet Synchro-nous Generator(PMSG)reaffirms the design.

某型舰船设备大负载复合材料支承冲击强度试验方法研究

舰船设备支承件的冲击特性研究受到各国海军的重视,然而超过常规冲击机能力范围的冲击载荷等要求,使得开展大负载支承件冲击强度试验成为难题。以某型动力设备的大负载复合材料支承为对象,采用水下非接触爆炸的方式,以标准浮动冲击平台冲击环境为输入参数设计其冲击强度试验方法:在低速冲击条件下,通过保证冲击载荷、降低试验负载质量、提高系统安装频率的途径来设计试验装置,依据冲击谱和冲击载荷计算对应的试验冲击因子来设计强度试验工况,并得出了实际试验与设计参数之间因试验系统多个结合面对冲击载荷传递影响的折减系数。试验结果表明,复合材料支承承受的冲击载荷与要求值之间的偏差在5%以内,为今后开展类似试验提供了参考。

舰载直升机端齿式折叠型尾水平轴系振动特性研究

端齿式折叠机构可以实现尾水平轴系的折叠,增加航空母舰上停靠舰载直升机的数量;同时,端齿式折叠机构对直升机尾传动轴系振动特性也会产生一定影响。建立了舰载直升机端齿式折叠型尾水平轴系动力学模型,求解分析了轴系各支承处振动响应。首先,分别基于有限元法与应变能法对折叠机构中花键连接部分及端齿连接部分进行等效简化,将花键连接部分等效为径向刚度及转角刚度,端齿连接部分等效为等效环,建立端齿式折叠机构的动力学模型,并通过与有限元仿真对比模态分析结果的方法以验证建模方法的准确性;在此基础上,将折叠装置动力学模型耦合到尾水平轴系中,建立折叠型尾水平轴系动力学模型,求解并分析了轴系振动特性。研究结果表明,各支承中,位移响应最大的在关节轴承处,最小的在主减输出端轴承处;振动响应与支承位置及其刚度阻尼特性有关。该研究可为轴系支承配置研究提供理论指导。

有源前端组网的直流船舶电网高能效运行控制

直流船舶电网为航运业绿色转型提供了有效可行的解决方案。考虑到实际船舶的运行工况,本文提出一种分层协调控制策略,主要用于有源前端组网的直流船舶电网中功率单元协调运行的设备层控制系统和功率层控制系统。其中,设备层控制系统负责实现发电机组转速的无静差跟随与不同容量柴油发电机组间的动态/稳态功率共享;功率层控制系统负责提升母线电压质量,提高系统能效。最后,利用仿真与半实物仿真系统对控制策略进行验证,结果表明该控制策略可有效提高系统运行能效,最高节省约10%的燃油。

船用核安全级电缆研制

通过分析特殊功能和环境适应性需求下船用核安全级电缆的分类和性能要求,进行了船用核安全级控制和仪表通信电缆的结构设计、材料选择和试制开发,后对试制电缆产品进行全性能测试。结果表明,该产品达到设计要求。

舰用雷达阵面在不同冲击环境下的响应分析

通过理论计算和有限元仿真,研究舰用雷达阵面在不同冲击环境下的响应。文中将冲击载荷作用下舰用雷达阵面的受力模型简化为基础激励的多自由度系统,通过对受力模型的边界模态进行虚拟约束的方法计算了不同冲击环境下的响应。结果表明:舰用雷达阵面响应基本不受冲击谱参数中谱加速度变化的影响,而谱位移和谱速度对舰用雷达阵面响应影响较大。分析结果可为冲击环境下舰用雷达阵面的响应分析和影响评估提供参考。

Analysis of tidal and residual currents across semi-enclosed bay mouth based on shipboard ADCP measurements

Based on 25 hours shipboard ADCP measurements across semi-enclosed bay mouth（Kemen Channel）, time series of tidal currents over 12 sites, which distribute evenly along the transect, were constructed to improve our understanding of tidal characteristics and residuals in this region. The tidal currents in Kemen Channel were identified as the regular semidiurnal and reversing tidal flows, with its behaviour more like standing waves. Moreover, the flood currents in the lower layers were found to be ahead of that in the upper layers and vice versa for ebb tides. The major of tidal ellipse for M2 constituent was found to be larger close to the southern side of the channel, with its incline also increasing toward the south. The signs of M4 constituent were also found mainly nearby the end points of this transect, indicating the importance of nonlinearity in tidal dynamics due to the shallower topography. A two-layer structure was found for the residual currents in Kemen Channel, flowing northeastwardly out of the Bay in upper 20m and southwestwardly into the bay in the lowers. Besides approximate 4.81×10^8 m^3 water exchanges were determined between the Luoyuan Bay and outer seas by the calculation of tidal flux through Kemen Channel.

船舶中压直流综合电力系统(一):系统结构和电力电子变换器

船舶中压直流综合电力系统具有高功率密度、高运行灵活性等优势,是我国实施海洋强国战略的重要基础。该论文的第一部分首先分析了船舶电力系统的发展趋势,从拓扑结构、电压等级、接线形式、接地方式等角度梳理了船舶中压直流综合电力系统的特殊系统结构;然后,根据现有文献详细阐述了发电侧整流器、推进变流器、DC-DC变换器等船舶中压直流综合电力系统关键电力电子变换器的研究现状,并进行了详细对比;最后,总结了船舶中压直流综合电力系统与陆上直流微电网的典型差异,并梳理了国内外相关技术标准。

基于数据-知识驱动的高精度海底地形绘制:以南海为例

海底地形具有非常重要的商业、工程、军事和科学研究价值。目前,常用重力场数据反演海底地形,如自由空气重力异常和垂直重力梯度。然而,由于现有方法反演海底地形具有较强的多解性,仍然无法准确获取高精度的海底地形。该文提出了重力-密度法与随机森林结合的数据-知识驱动新方法,以重建准确的海底地形。该方法在中国南海海域进行了测试,并与重力-密度法、随机森林以及现有的SIO模型进行了对比分析。反演结果显示,数据-知识驱动提供了更好的反演性能,随机森林和重力-密度法次之,SIO模型最差。相比于重力-密度法,数据-知识驱动的平均绝对误差、平均相对误差和均方根误差分别降低了21%、25%和7%;而相比于随机森林,它们分别也降低了20%、20%和20%。此外,数据-知识驱动模型与船载测深数据具有较高的一致性,其差值大约有72%分布在±10 m范围内,占比高于其他三种模型。该结果证明了数据-知识驱动方法在海底地形反演中的可行性和有效性,有助于加快高精度海底地形的绘制。

基于BP-SA混合学习策略优化的舰载消磁系统在役考核评估方法

装备在役考核是验证装备服役后的作战与保障效能,促进装备迭代升级的重要手段。针对舰载消磁系统在役考核工作特点和常规考核评估方法的不足,从作战效能、适用性、可靠性、维修性以及测试性等5个方面建立了舰载消磁系统在役考核指标体系。在传统BP神经网络的基础上,引入模拟退火策略随机寻找更优解,提高了神经网络的收敛性和稳定性。评估模型经过70组舰载消磁系统数据样本的训练、测试和验证,最终得到剩余预测残差RPD为9.3093的实验结果,表明了该模型不仅克服了传统BP神经网络算法局部极小、拟合效果差等问题,且对于舰载消磁系统在役考核结果具有很好的预测与评估能力。

北斗三号新型船载终端设计

针对北斗二代卫星导航系统终端在精度、可靠性和智能化程度等方面存在缺陷,提出采用北斗三号卫星导航系统新技术,设计出新型船载终端。采用北斗三号卫星导航系统的定位技术和通信技术,对终端的硬件结构和软件系统进行设计和实现。结果表明,结合物联网等通信技术,采用高精度北斗定位结合GIS地理信息技术,将北斗+物联网通信技术相互兼容,结合计算机数据库管理和电子海图技术,利用北斗三号卫星导航系统特点可以设计出新型船载终端。终端设计能提高海上船舶实时动态监管和应急救助处置能力,构建快捷高效的应急救助体系。

基于舰艇平台授时技术现状及发展研究

为了解军用授时技术现状及发展,结合基于舰艇平台的授时技术对自身及编队时间统一能力的深刻影响,对国内外军用授时技术发展现状进行了相应的研究。通过对授时基本技术、授时技术在国内舰艇的应用、国外军用授时技术发展等方面的理论研究,概括了基于舰艇平台的授时技术现状及发展情况,最后总结提出了我国未来授时技术的发展方向以及需要大力加强无外部授时源方法研究,旨在为未来军用授时技术的发展研究提供一定的参考。

Optimal Bidding Strategies of Microgrid with Demand Side Management for Economic Emission Dispatch Incorporating Uncertainty and Outage of Renewable Energy Sources

In the restructured electricity market,microgrid(MG),with the incorporation of smart grid technologies,distributed energy resources(DERs),a pumped-storage-hydraulic(PSH)unit,and a demand response program(DRP),is a smarter and more reliable electricity provider.DER consists of gas turbines and renewable energy sources such as photovoltaic systems and wind turbines.Better bidding strategies,prepared by MG operators,decrease the electricity cost and emissions from upstream grid and conventional and renewable energy sources(RES).But it is inefficient due to the very high sporadic characteristics of RES and the very high outage rate.To solve these issues,this study suggests non-dominated sorting genetic algorithm Ⅱ(NSGA-Ⅱ)for an optimal bidding strategy considering pumped hydroelectric energy storage and DRP based on outage conditions and uncertainties of renewable energy sources.The uncertainty related to solar and wind units is modeled using lognormal and Weibull probability distributions.TOU-based DRP is used,especially considering the time of outages along with the time of peak loads and prices,to enhance the reliability of MG and reduce costs and emissions.

舰船电力系统自组织临界特性分析

基于自组织临界理论,以直流潮流为基础,建立了舰船电力系统连锁停电的OPA模型。通过OPA模型模拟了舰船电力系统发生连锁故障的过程并揭示出舰船电力系统发生大停电事故的本质;研究了线路可靠性和线路容量对系统停电分布的影响,结果表明,增强线路可靠性和提高线路容量有利于系统抵御连锁故障。此外,对比环形舰船电网结构和辐射型舰船电网结构的停电规模分布,从系统自组织临界特性的角度验证环形舰船电网结构可靠性更高。

大型舰船补给环境下引信意外跌落冲击响应特性

为了研究舰船在吊装补给转运中全包装引信弹药意外跌落的响应特性问题,通过ANSYS/LS-DYNA软件建立引信弹药包装箱动力学仿真模型,开展了典型跌落环境下引信冲击响应特性分析,获取了引信及安全与解除隔离装置在不同跌落环境下的响应特征规律。搭建了引信包装箱跌落测试环境,测定了典型跌落工况下引信过载数据,验证了引信包装箱动力学仿真模型的准确性。试验验证结果表明引信及包装箱在3 m、12 m水平跌落工况下,仿真与试验过载误差为14.4%、12.0%,脉宽误差分别为2.0%、9.4%。通过进一步仿真计算发现,大高度、垂直,跌落地面为921A舰船甲板的工况下引信安全与解除隔离装置过载峰值最大。不同跌落地面材料下的引信的跌落过载响应大小顺序为:舰船甲板材料921A钢>45号钢板>混凝土。引信的过载响应值随其跌落高度增加迅速增加。引信的安全与解除隔离装置过载响应值随其跌落角度增加先减后增。

舰用电子产品失效机理分析与加速模型构建

舰用电子产品具有高可靠与长寿命的特征,其可靠性水平的快速评估是保障质量的重要手段,文章给出了一种适用于舰用电子产品的加速模型构建方法。首先,收集与分析航行海域气象信息,量化主要海洋环境与应力量值;其次,开展舰用电子产品特征分析和故障机理分析,给出电子产品典型失效模式及其敏感应力;最后,给出了基于故障物理的加速模型构建方法,确定了低温-65 ℃,高温90 ℃,温变速率15 ℃/min的加速应力,加速因子5.6,为快速评价舰用电子设备寿命指标提供了参考。

基于数字孪生的走航式ADCP二维流速场研究应用

河流水文信息的孪生模拟再现是数字孪生流域建设的重要内容与水文信息处理的新方式。为实现走航式ADCP二维流速场数字孪生应用,利用流速分布理论公式,假定二维流速场分布,将走航式ADCP的流速实测值作为样本,运用最小二乘法,推算出流速场分布的线性系数,得到二维流速场分布函数,以代表整个流速场。结果表明:在汉口站、白河站不同水位级、流量级下,得到的流量值与实测流量误差在1.7%以内,说明该方法得到的流速场分布与实测流速场分布基本一致,有利于开展河流水文信息的处理分析。研究成果可为河流断面水文信息数字孪生建设与挖掘实测水文信息及内在分布变化规律等提供参考。