双向逆变器的并网控制策略研究

介绍了一种基于纯交流母线供电的风光柴互补发电系统中蓄电池充放电的装置,即双向逆变器,并对它的并网运行模式进行了深入研究,阐述了它在并网运行模式下的拓扑结构、工作原理、控制方案.在此基础上设计出一台2 kW实验样机,实验结果表明该双向逆变器在并网模式下可以实现能量的双向流动,具有较高的功率因数,满足并网运行要求.     

30kW一体式微网光伏储能逆变器拓扑运用研究

随着社会的发展,对电力的需求逐步增加,能源危机、环境污染、智能电网建设以及可再生能源发电建设滞后等因素之间的矛盾,催生出一个新的电力电子解决方案与产品——微网储能系统。微网储能系统通常与光伏结合,是目前比较成熟、可靠、方便的系统解决方案,其中,微网光伏储能逆变器作为关键组成部分,其光伏DC/DC变换器、电池DC/DC变换器、双向并离网DC/AC逆变器的拓扑结构的选择决定系统功能参数与可靠性。通过分析各种拓扑结构优劣势,根据实际需求,选择一套最优化的拓扑结构方案,以此作为类似产品规划设计借鉴。     

微电网运行控制策略研究

该文以深圳职业技术学院微电网工程为研究对象,针对面向可再生能源的微电网系统如何实现分布式电源、储能装置、负荷之间的协调,达到系统的稳定和最优运行,制定了运行控制策略。针对并网运行、离网运行,分多种工况来进行现场试验。测试结果表明,该微电网系统可连续稳定运行,并/离网启动、运行、切换都能满足控制要求。     

小型多模式智能逆变器控制方法研究

针对分布式发电的特点,提出一种多端口输入的新型逆变器拓扑结构,可同时接入两路光伏发电单元和一路储能单元,并实现整个系统的模式切换和智能控制,解决了传统户用逆变器工作模式单一的问题,能够满足更多用户的需求。在充分理论研究的基础上,设计出了多端口逆变器的具体电力电子拓扑,并对硬件设计做了大致介绍,详细说明了每个模块的控制策略和各个模块之间的协调控制策略,并给出控制框图。应用Matlab/Simulink对多端口逆变器的拓扑和控制策略进行仿真,对仿真结果进行介绍和分析。搭建5kVA硬件平台,对拓扑以及算法进行验证。最后通过对实验波形的介绍和分析,说明以上理论的正确性和可行性。     

一种可并网光伏发电逆变器设计

文中介绍了一种可并网式光伏发电逆变器设计方案,给出了光伏发电系统的组成结构,重点对逆变器的核心前级DC/DC升压器与后级DC/AC变换器的拓扑结构和电路相关参数设计进行了详细分析说明。按照此方法设计了电路,并给出了输出电压波形的仿真结果与相关测量数据。实验结果表明:该系统输出电压技术指标满足并入市电电网的要求,达到了并网的目的。     

浅谈某办公楼离网式光伏储能发电系统设计

离网式光伏储能发电系统,在不具备电网接入条件的情况下,可以提供很好的用电解决方案。本文针对某办公楼离网式光伏储能发电系统,从项目特点、系统构成、装机容量计算、主要设备选型、设备布置安装、需注意的相关问题、工程量及项目效益等方面进行了论述,给出了较完善的解决方案,并对离网式光伏储能发电系统的发展进行了展望。     

光储联合发电控制策略研究

讨论并提出电池储能在并网光伏发电系统中的应用模式,基于DIgSILENT仿真平台,建立光伏发电及电池储能系统模型,仿真分析不同应用模式下光伏—储能联合发电系统的运行特性。结果表明:电池储能系统能够有效平抑并网光伏系统的出力波动,有利于减轻光伏发电功率波动对电网的冲击。     

基于台区融合终端的分布式储能型光伏并网电能质量研究

为解决并网光伏发电系统电能质量波动问题,提出了基于台区融合终端的光伏储能并网电能质量系统设计方案。分析了分布式储能型光伏并网的基本框架,说明了电能质量监测的基本参数。设计了台区融合终端电能治理方案,分为融合终端配合储能系统电能治理、融合终端配合储能PCS电能治理和融合终端配合智能光伏隔离开关电能治理3种方案。针对电池储能PCS系统进行设计,说明了智能光伏隔离开关的主要技术原理和微应用总体架构。最后针对某地区电网实际光伏并网进行应用分析。     

一种基于SHE-PWM控制法的单相光伏逆变器设计与研究

设计了单相光伏发电并网逆变器的结构,并采用基于SHE-PWM控制法控制的单相全桥逆变方案,分析计算了SHE-PWM控制法的开关控制角度。通过在MATLAB/Simulink中的仿真可以看出,该逆变器和SHE-PWM控制法能够满足光伏发电单相并网的要求,可以在工程中应用。     

基于DSP的3kW单相光伏并网逆变器设计

基于光伏并网逆变器的基本原理和拓扑结构,提出一种基于DSP的3 k W非隔离型光伏并网逆变器的设计。通过理论分析和计算,进行电路元件参数的设计,包括主电路参数、检测和保护电路、驱动电路的设计。搭建3 k W实验样机一台,样机实验表明,该设计方案满足了逆变器的设计要求,能够实现安全、可靠并网运行,输出电流具有较低的谐波含量。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.