用于电弧检测的电力专用SoC设计

针对传统的电弧电路故障检测结果不准确的问题,设计用于电弧检测的SoC系统,并且在55nm工艺下进行流片验证。采用包含两种结构的模数转换器的片上电压源,设计了锁相环以及复位电路,精度最高可达8.67 bit。验证结果表明,本设计可提高电弧检测的准确性。     

碳酸性侵蚀与AAR作用下纳米混凝土的耐久性

地铁混凝土处于地下空间,容易受到地下水的碳酸性侵蚀；碱集料反应 (AAR)是一种严重的混凝土耐久性问题,既难以发现又难以修补,由两者共同作用引起的混凝土耐久性降低严重影响地铁隧道的正常使用.为研究纳米材料对地铁混凝土在碳酸性侵蚀和AAR共同作用下耐久性的影响,在普通混凝土中掺入适量纳米SiO₂和纳米Fe₂O₃,利用自行研制的碳酸性侵蚀试验箱进行试验,采用碳酸性侵蚀深度、膨胀率和声速作为测试指标来评价纳米混凝土在碳酸性侵蚀和AAR共同作用下的耐久性.试验结果表明:掺入纳米颗粒后,混凝土的膨胀率和侵蚀深度有了明显降低,而声速有了明显提升,说明纳米混凝土的耐久性优于普通混凝土；在182 d龄期时,掺量为2%的纳米SiO₂混凝土耐久性改善最明显,侵蚀深度和膨胀率最小,声速最大且声速下降幅度最小；其次是掺量为1%的纳米Fe₂O₃混凝土.由于纳米颗粒特殊的物理化学性质,改善了混凝土内部的微观结构和孔溶液的化学组成,使碳酸性侵蚀和碱集料反应共同作用下混凝土的耐久性得到了提高.     

计及RSC控制的DFIG短路电流直流分量解析表达

现有文献针对计及转子变流器(RSC)控制的双馈感应风电机组(DFIG)定子短路电流解析表达,将定子磁链当作一阶直流衰减分量或忽略功率外环控制。基于DFIG电压、磁链和RSC控制方程,得到定子电流关于定子电压和定子功率的传递函数,提出定子电流的精确解析表达式。基于RSC内、外环PI参数关系,推导直流分量衰减时间常数和角频率关于PI参数的表达式。分析了RSC内外环PI参数对定子电流直流衰减分量的影响。仿真结果验证了解析表达式的准确性,为PI参数选取和保护装置测量、整定提供依据。     

不锈钢管气体保护焊接工艺研究

为了确保不锈钢管道的焊接质量，通过分析不锈钢焊接及焊接保护气体的特点，对焊接工艺进行了设计，并对某项目规格为Φ323.9 mm×25.4 mm奥氏体不锈钢管道背面充氩焊接工艺进行了分析介绍。结果表明，采用可靠的充气工装使焊缝背面得到有效的保护（残余氧含量按不超过1%的水平），防止焊缝背部出现氧化现象；选取合理的气体流量和压力，能确保焊缝内部成形，满足焊缝质量要求；采用合适的焊接工艺与背面保护措施，可获得满足要求的焊接接头性能。     

A new controller for boost dc–dc converters based on a novel sliding surface

ABSTRACT

In this paper, two control schemes for boost converters affected by uncertainties in input voltage and load are proposed. The boost converter dynamics is redefined in terms of new state variables to facilitate the use of a disturbance observer that can estimate matched and unmatched disturbances. A sliding surface, which is new in the context of boost converters, is proposed to enable tracking and regulation of output voltage without requiring measurement of input voltage and load current. The stability of the overall system including the disturbance observer, the sliding variable and the output is proved. The performance of the schemes is assessed for regulation of output voltage and tracking of reference voltage by simulation as well as experimentation in which various types of uncertainties and various types of reference voltages are considered.     

交错巷道巷间围岩承载结构稳定性分析

针对普遍存在的矿井交错巷道围岩体稳定性及支护问题,运用极限平衡分析和弹塑性力学建立交错巷道巷间围岩稳定性分析判别方程,探讨了交错巷道巷间围岩稳定性主要影响因素,并进行了工业性试验。结果表明:交错巷道巷间围岩体受围岩水平应力集中叠加影响,围岩破坏自巷间围岩体上下表面向中部延伸,加之巷间围岩体尺寸有限,一旦破坏贯通将致使巷间围岩承载存在失稳隐患;交错巷道巷间距越小,越近乎平行布置都会加剧巷间围岩破坏且诱发巷间围岩破坏贯通,合理设计断面尺寸及下方巷道合理支护强度可有效控制并维持围岩稳定;现场采用交错巷道联合支护方案后,交错位置上巷道断面完整无较明显变形且下巷道围岩最大变形量小于100 mm,支护效果显著。     

超临界蒸汽参数对燃气蒸汽联合循环性能影响研究

为进一步提高联合循环效率,参考现有燃气蒸汽联合循环12.5 MPa/568℃亚临界蒸汽参数,提出27 MPa/585℃超临界蒸汽参数,根据燃气蒸汽联合循环计算模型,以397 MW燃气轮机联合循环机组为例,计算了超临界蒸汽参数与两种亚临界蒸汽参数的底循环效率和联合循环效率,并分析对比了3种蒸汽参数的底循环效率对联合循环效率的贡献。研究表明:对于同一燃气轮机,超临界和亚临界中低压蒸汽参数不同时,超临界蒸汽参数的底循环效率比亚临界提高了4.3%,蒸汽底循环输出功率占联合循环机组输出功率的百分比由30.21%增加到32.62%,联合循环净效率增加了2.21%,联合循环机组的输出功率增加了20.38 MW;中低压蒸汽参数相同时,超临界蒸汽参数的底循环效率比亚临界提高了2.87%,蒸汽底循环输出功率占联合循环机组输出功率的百分比由31.16%增加到32.62%,联合循环净效率增加了1.44%,联合循环机组的输出功率增加12.5 MW。     

A New Design Methodology for Time-Based Capacitance-to-Digital Converters (T-CDCs)

This paper introduces a 9-bit time-based capacitance-to-digital converter (T-CDC). This T-CDC adopts a new design methodology for parasitic cancellation with a simple calibration technique. In T-CDCs, the input sensor capacitance is first converted into a delay pulse using a capacitance-to-time converter (CTC) circuit; then this delay signal is converted into a digital code through a time-to-digital converter (TDC) circuit. A prototype of the proposed T-CDC is implemented in UMC 0.13 μm CMOS technology. This T-CDC consumes 8.42 μW and achieves a maximum SNR of 45.14 dB with a conversion time of 1 μs that corresponds to a figure of merit (FoM) of 16.4 fJ/Conv.     

Combined constant speed control method for a wind generator equipped with hydraulic energy storage

A wind generator equipped with hydraulic energy storage (WG‐HES) uses hydraulic transmission systems instead of gearbox transmissions, thus eliminating high‐power converters and reducing the tower‐top cabin weight. When there is no wind or the wind speed is extremely low, the pressured oil released by accumulators is used to drive a motor to operate at a constant speed, thereby generating constant‐frequency power. However, few studies have examined the constant speed control characteristics for generating electricity using only an accumulator group. In this study, a combined constant speed (CCS) proportional–integral–derivative (PID) control method based on “variable displacement and throttling” is proposed, which includes two closed loops and one regulating loop. First, a simulation model of the CCS PID control method for a variable motor was established in the Simcenter Amesim program. The influence of different PID parameters on the anti‐interference ability of the constant speed control of the motor was analyzed under a given load step. Then, we obtained the range of control parameter values and a set of optimal values. Second, the effectiveness of the CCS control method and the accuracy of the simulation results were verified on a 600‐kW WG‐HES system prototype. The results verified that the CCS control method has good anti‐interference ability and can meet the requirements of constant speed control for a variable motor under the best PID parameters. These results can provide a basis for developing control strategies for WG‐HESs when there is no wind or at low wind speeds.     

基于高压结合酶法制备的低敏虾制品体内体外致敏性检测的差异性分析

采用高压结合酶法处理凡纳滨对虾的虾蛋白、虾仁泥(虾肉)和虾仁,获得3种低敏虾制品;采用酶联免疫吸附法检测3种虾制品的过敏原性,采用全身性过敏反应(过敏性休克模型)及致敏离体回肠平滑肌收缩实验(Schultz-Dale反应)检测3种低敏虾制品的致敏性,以分析体内与体外方法检测虾制品致敏性的差异性。结果显示:处理前的3种原料过敏原性极高。经高压结合酶法处理的虾蛋白、虾肉和虾仁的过敏原性分别消减97.0%、94.1%和94.5%。而在动物实验中(以磷酸缓冲盐溶液为阴性对照,未处理虾蛋白为阳性对照,以豚鼠为受试对象),未处理虾蛋白组的过敏反应发生率与死亡率均为100%,3种低敏虾制品的过敏反应发生率也为100%,死亡率分别为16.7%(虾蛋白产物)、50%(虾肉产物)和83.3%(虾仁产物)。致敏的离体回肠受到3种低敏虾制品攻击后,收缩力也明显增强,分别达到376.9%、766.2%和1 004.4%。上述结果表明,对高压结合酶法制备的低敏虾制品过敏原性的检测,体外检测与体内检测存在一定的差异性。