基于电流馈电推挽式变换拓扑的变换器电源设计

以提高变换器电源的效率和可靠性为目标,设计了基于电流馈电推挽式变换拓扑的变换器电源。为使变换器电源具备开关管以零电压开关方式通断、开关频率恒定等理想特性,采用电压型推挽全桥逆变器,设计属于电流馈电推挽式变换拓扑结构的变换器电源装置主回路。选择DSSK60-015A全波整流二极管作为变换器电源主回路硬件;通过反馈控制电路调控电压波动时控制端流变化;根据变压器电感、匝数、线径等特性设计变压器绕制结构,完成变换器电源变压过程;设计保护电路,保证电源可靠工作。实验结果表明,所设计的变换器电源的输出电压、电流误差范围均在2%内,开关管实现了零压开通,变换器电源功率因数均保持在0.96以上,且效率高达95%。     

基于二极管-电容倍压单元的DC-DC升压变换器

文章基于二极管-电容倍压单元,提出了一种新型高增益升压变换器。该拓扑在实现高增益的同时可以避免使用极大的占空比,并且有效地降低开关管和二极管的电压应力。分析了变换器的工作原理,推导了变换器工作在连续状态（CCM）和断续状态（DCM）下的电压增益、开关器件的电压应力和电感电流纹波。CCM状态下与传统的Boost变换器相比电压增益是其（5-D）倍,电感电流纹波近似减小为原来的一半。最后通过仿真与样机实验验证了理论分析的正确性,表明提出的变换器具有良好的综合性能。     

基于下垂控制模式的独立微电网小干扰稳定分析

从电力系统的运行原理出发,开展独立微电网系统运行稳定性研究对于促进分布式发电技术的发展具有重要意义。针对独立微电网系统运行稳定性问题,以李雅普若夫判据和特征值分析法为基础,对基于下垂控制模式的独立微电网系统的小扰动问题展开分析。首先,构建基于下垂控制模式的独立微电网系统数学建模,并基于线性化理论进行小扰动线性化分析,得到系统小扰动线性化状态矩阵;其次,基于李雅普若夫判据理论,对系统小扰动线性化状态矩阵的特征值进行分析,并逐一改变系统各个参数取值范围得到状态矩阵特征值变化的根轨迹;最后,基于状态矩阵特征值变化根轨迹确定系统各参数初步优化结果,并对比各参数优化前后的系统状态矩阵特征值分布情况,理论分析及实验验证表明初步优化后的系统运行可靠性增强。该研究成果可为微电网控制参数的优化选取提供思路和方法。     

不同倍率下磷酸铁锂电池模组过充热失控特性研究

随着电化学储能技术在电力系统中的广泛应用,电化学储能技术的安全性越来越受到重视。文中以储能用磷酸铁锂电池模组(8.8 kW·h, 25.6 V,344 A·h)为研究对象,进行3次不同倍率(0.4C,0.5C,1C)的恒流过充试验,研究其在不同充电倍率条件下的过充热失控特性,并辅以starccm+软件进行热场仿真计算。结果表明,电池模组在额定充电倍率0.5C(172 A)和1C(344 A)下持续过充会发生起火,起火时间随着充电倍率增加而减少;充电倍率对磷酸铁锂电池模组过充行为特性影响较大,随着充电倍率的增加,热失控最高温度和峰值电压升高,过充测试时间随着充电倍率的升高而降低;不同充电倍率条件下,电池安全阀首次打开时的电压均为1.7倍额定电压,可以进一步研究以作为电池热失控预警参数。文中研究成果可为规模化储能用磷酸铁锂电池的安全性研究和电池管理系统(BMS)对过充故障的安全管理提供参考。     

光热电站容量效益评估及影响因素研究

光热发电作为一种清洁能源,配置储热后具有良好的调节性能,近年得到大力发展。依据自身经济性,光热电站往往配备较大的储热装置,能够平移所吸收的光热能,且具有跨日调节能力,使得光热机组有一定替代常规机组带负荷的能力,即容量效益。本文提出一种基于等可靠性的光热电站容量效益评估方法,考虑了调峰方式、储热时长、新能源规模、光热电站规模对光热电站容量效益发挥的影响,采用基于数学优化的生产模拟仿真程序,以周为尺度,计算全年8760 h的系统运行状态,计及了机组启停、水电跨日调节、抽蓄跨日调节、光热电站的跨日调节等因素。最后通过对西北地区实际电网的仿真,验证了所提方法的有效性。     

UPFC系统的变压器差动保护分析

并联变压器和串联变压器是统一潮流控制器(UPFC)的核心交流器件,差动保护作为这两类变压器的主保护,受UPFC特殊的运行工况影响,在不同的运行条件和不同类型的故障下会表现出不同的特性。为分析评估UPFC中各类故障对差动保护的影响,文中以实际UPFC工程的控制系统为基础,讨论了各类故障下可能对并联、串联变压器差动保护灵敏性及可靠性产生影响的因素;根据变压器区内外典型故障的仿真结果,分析了差动保护在此类故障下的行为特征,形成差动保护的适应性分析,验证了保护配置的有效性;从保护设备的角度出发,讨论了阀控制保护与交流继电保护的关系,从防误和防拒两方面为UPFC工程的交流继电保护实施提供技术参考。     

Pressure Response through Valve for Continuous Oil-Water Separation Based on a Flexible Superhydrophobic/Superoleophilic Thermoplastic Vulcanizate Film

Highly efficient oil-water separation shows urgent demand in industrial applications, especially in oil-spill accidents and organic solvent separation. Herein, a novel method is proposed for continuous oil-water separation by a pressure response through valve, which is loaded in a flexible convolute superhydrophobic/superoleophilic film based on low-density polyethylene (LDPE)/ethylene-propylene-diene terpolymer (EPDM) thermoplastic vulcanizate (TPV). The superhydrophobic/superoleophilic LDPE/EPDM TPV film (with contact angles of oil and water are 0° and 161.9°± 2.2°) is prepared only via a molding process where sandpaper is used as the template. The superhydrophobic/superoleophilic property of the TPV film shows robust performance in the activity endurance test. More importantly, the flexible LDPE/EPDM TPV film can be easily rolled up and loaded in through valve, which is the pressure response channel in oil-water separation. The typical separation pressure of oil and water is 3.01 and 6.17 kPa, which means the oil can be completely separated from the oil-water mixture under proper pressure in the pressure response through valve.     

电网故障处置预案文本中的命名实体识别研究

电网故障处置预案是电网故障处置的重要参考,对电网故障处置预案文本中各类电力设备、名称编号等细粒度的关键实体信息进行抽取,是实现计算机学习理解预案内容并进一步支撑故障处置智能化的重要基础。文中提出一种基于深度学习的电网故障处置预案文本命名实体识别技术,首先采用字向量表征预案文本,然后将注意力机制以及双向长短期记忆网络相结合,有所侧重地提取实体词深层字符特征,最后采用条件随机场求解最优序列化的标注。算例表明:文中所提预案文本命名实体识别模型不依赖人工特征,能够自动高效地提取文本特征,准确识别预案文本中细粒度的实体词,满足预案文本中关键实体信息精确定位和识别的要求。     

A Strategy of Liquid-Grafted Slippery Sponges with Simultaneously Enhanced Absorption and Desorption Performances for Crude Oil Spill Remediation

Crude oil spill accidents pose a worldwide environmental threat. Oleophilic and hydrophobic absorbents that can selectively absorb oil from water have shown promising application potential in oil spill remediation. Simultaneous optimization of the absorption and desorption speed of absorbents towards oil is highly desirable for their recyclable usage, but remains a great challenge, because these two properties are generally conflicting. Here, a facile and ingenious strategy is proposed to tackle the above challenge via surface modification of porous sponges with highly flexible linear polydimethylsiloxane (LPDMS) brushes. The LPDMS brushes feature liquid-like properties at room temperature owing to its extremely low glass transition temperature, and act as a covalently-grafted lubrication layer throughout the 3D network channels of the sponge, which can minimize contact angle hysteresis and reduce friction between oil and sponge channel. Compared to the prevalent cross-linked polydimethylsiloxane (CPDMS) modification strategy, sponges modified with LPDMS brushes not only shows significantly enhanced absorption speed, but also exhibits superior desorption dynamics towards viscous crude oils. The design strategy of slippery sponges with liquid-like molecules may open a new avenue for developing advanced absorbents with simultaneously enhanced absorption and desorption performances for liquid separation and purification applications.     

Preparation and Bioactivity of Iridium(III) Phenanthroline Complexes with Halide Ions and Pyridine Leaving Groups

A series of half-sandwich structural iridium(III) phenanthroline (Phen) complexes with halide ions (Cl⁻, Br⁻, I⁻) and pyridine leaving groups ([(η⁵-Cp^X)Ir(Phen)Z](PF₆)_n, Cp^x: electron-rich cyclopentadienyl group, Z: leaving group) have been prepared. Target complexes, especially the Cp^xbiph (biphenyl-substituted cyclopentadienyl)-based one, showed favourable anticancer activity against human lung cancer (A549) cells; the best one ( Ir8 ) was almost five times that of cisplatin under the same conditions. Compared with complexes involving halide ion leaving groups, the pyridine-based one did not display hydrolysis but effectively caused lysosomal damage, leading to accumulation in the cytosol, inducing an increase in the level of intracellular reactive oxygen species and apoptosis; this indicated an anticancer mechanism of oxidation. Additionally, these complexes could bind to serum albumin through a static quenching mechanism. The data highlight the potential value of half-sandwich iridium(III) phenanthroline complexes as anticancer drugs.