庞庞塔煤矿综采工作面恒压供液系统研究

结合庞庞塔煤矿综采工作面的具体应用现状,设计了变频驱动控制的恒压供液系统。在泵出口管道中设置压力传感器、流量计等,同时在每台液压支架乳化液入口处安装一个蓄能器。压力、流量等数值由各种传感器来进行采集,并把监测到的数据反馈给PLC控制器。PLC控制器通过把传感器送来的数据和系统预设好的数值进行比较来判断供液系统是否需要加压或着减压,以此通过变频器来改变电机的转速,以实现供液系统维持恒压状态。     

SC15/182F分体式电驱梭车的研制及应用

梭车是短壁机械化开采技术的重要运输设备。简要介绍了现有梭车的现状及应用局限,详细阐述了分体梭车的主要设计思路,重点介绍了薄壁分体式机架的结构特征,阐述了分体梭车在模块化卷电缆装置、四象限变频驱动等方面的技术升级,并介绍了分体梭车在国内矿区的应用情况。     

Estimating the system efficiency of the multifunctional hydrogen complex at nuclear power plants

The paper deals with the primary current frequency regulation in the energy system (ES) as well as the basic requirements for NPP power units (PUs) under the conditions of involvement into the primary regulation. According to these requirements, NPP operation is related to the unloading and corresponding decrease in efficiency. It has been shown in this connection that combining NPP with a hydrogen complex (HEC) allows excluding the inefficient unloading mode. This enables the steam turbine and reactor equipment to operate in the basic mode at nominal power level. Besides, the conditions for producing and storing hydrogen and oxygen during the day as well as additionally during the night-time of off-peak electrical load may be created, which allows using them for generating peak power.In the paper, the systemic economic benefit as a result of involving NPP combined with HEC into primary regulation of the current frequency in ES with allowance for expending resources for the main equipment has been estimated. In this regard, the paper gives grounds for cyclic loadings of HEC main equipment including metal tanks for storing hydrogen and oxygen, compressors, hydrogen-oxygen combustion chamber (HOCC) for hydrogen-steam superheating of the actuating medium in the NPP steam turbine cycle. Methodological grounds for evaluating the equipment endurance under cyclic loading with involving into the primary frequency regulation by the criterion of the fatigue crack growth rate are described. It has been shown that in terms of HEC equipment, the highest load intensity occurs in HOCC due to high thermal stresses.Also, the systemic economic benefit has been estimated, and the impact of the equipment deterioration under conditions of cyclic loading has been demonstrated. It is shown that when combining NPP PUs with HEC, the efficiency of primary regulation may significantly depend on such factors as the cost of equipment exposed to cyclic loads, the frequency and intensity of cyclic loads, and the relation between the peak electricity tariff and the cost price of electric energy produced by NPP.It has been shown on the basis of novel methods for estimating the efficiency of involving NPP with HEC into the primary frequency regulation with allowance for damage to the equipment, that the use of HEC may provide a considerable economic benefit, as compared to the version of NPP unloading when involving directly into frequency regulation.     

东峡煤矿主煤流运输系统智能化集控设计

通过对东峡煤矿主煤流运输系统的改造,设计了一套智能化集控系统,采用变频驱动,并结合料流传感器,增设无线基站、本安网络摄像仪和语音扩播终端等设备,实现了带式输送机载荷分布的自动调节,提高了系统的可靠性和运行效率,实现了减员、节能、增效的目的。     

汽油缸内直喷喷雾在不同壁温和二次喷射下的附壁油膜特性研究

采用激光诱导荧光(laser induced fluorescence,LIF)法测量缸内直喷喷油器喷雾附壁油膜的厚度分布,研究了附壁油膜质量和平均厚度随不同的壁面温度和喷射策略的变化。结果表明:常温壁面下油膜呈"波浪状",热壁面下油膜的边缘轮廓呈"带状"凸起,在壁面温度为413K时,还出现了聚集的小液滴。保持总喷油量不变,随着壁面温度的增大,单次喷射的附壁油膜质量逐渐减小,二次喷射的附壁油膜质量先减小后增大,单/二次喷射的附壁油膜平均厚度都逐渐增大;相对于单次喷射,相同热壁面温度下的二次喷射附壁油膜平均厚度都较小,在壁面温度同为413K时最多减小了42%。仅增加第二次喷射的喷油脉宽,壁面温度为298K和373K时的附壁油膜质量先增大后减小,壁面温度为413K时附壁油膜质量逐渐增大;相同喷油脉宽下,壁面温度为413K时附壁油膜平均厚度最大,而壁面温度为298K和373K时附壁油膜平均厚度与喷油间隔相关。     

双PWM变频调速系统在矿井提升机中的应用

针对目前大部分矿井提升机仍采用转子串电阻调速方法造成能量浪费的现状,提出了一种双PWM变频调速方案:三相电压型PWM整流器采用电压、电流双闭环控制,其中电流环引入前馈解耦控制,并结合空间矢量脉宽调制(SVPWM)算法来提高直流电压利用率。仿真实验的结果表明,该双PWM变频调速系统控制精度高、动态响应快、抗扰能力强,能有效地实现矿井提升机的节能降耗。     

Effects of electrical parameters and their interactions on plasma electrolytic oxidation coatings on aluminum substrates

Based on orthogonal experiments, the effects of voltage, frequency, duty ratio and their interactions on the thickness and corrosion resistance of coatings prepared by plasma electrolytic oxidation (PEO) on aluminum in an alkaline silicate-containing electrolyte were investigated. The thicknesses of these coatings were obtained by measuring their cross-section using Image J software. Their corrosion resistances were evaluated in HCl and NaCl media through spot test and electrochemical test. The results show that the experimental design of this study is the key to investigate the interactions among these electrical parameters. Additionally, not only each independent factor, but also their interactions exhibit a remarkable influence on the coatings. The combination of high voltage, low frequency and large duty ratio significantly increases the coating thickness and content of the corrosion resistance phase, and thus improves the corrosion resistance of the coating in HNO₃ medium. Conversely, the coating possessing the densest microstructure and best corrosion resistance in NaCl medium is obtained when low voltage and high frequency match with a small duty ratio.     

射频法原油含水率频率参数优化

根据电磁场相关理论研究、水和油两种介质的介电常数差异性较大以及在不同频率下含水率的特性来进行参数优化与设计,选择最优参数来提高含水率测量范围。对不同频率测量下含水率测量的大量实验,可以得出在含水率0%～100%范围内测量下,20MHz频率下幅度的曲线线性度较好,实现参数优化与设计。     

基于功频下垂控制的光伏并网发电系统惯量阻尼机理研究

针对光伏以低惯量、弱阻尼的特征大规模接入电网，给电网稳定性带来不利影响的问题，基于功频下垂控制的光伏并网发电系统，借鉴经典电气转矩分析法，从物理机制层面上分析影响系统惯量、阻尼以及同步能力的作用规律。研究结果表明对于控制参数的影响规律而言，惯量特性主要受功率环的比例系数Kp影响，且随Kp的增大而增强；阻尼特性受频率下垂系数Dp影响比较明显，且随Dp的增大而减弱；同步特性只受功率环的比例积分系数Ki影响，且随Ki的增大而增强。通过仿真验证了理论分析的正确性。