水流发电机在防长流水自关闭自动控制阀中的应用研究

防长流水自关断自动控制阀由水流发电机、脉冲电磁阀、控制器等构成,该阀能自动识别长流水并及时关断水流。小型水流发电机在是阀的关键部件,可将水流信号实时转变成相应的电压信号,经系统处理后可作为阀的水流流量信号,还可将发电电能通过充电电路对阀的充电电池进行充电,给阀供电。本文主要讲解水流发电机即作为阀的流量传感器又为系统供电的设计。     

基于太阳能的电动汽车充电站的研究

目前,电动汽车电池的续航能力有限是制约EV发展的重要因素,因此EV的充电方式成研发的重点。针对充电不确性情,提出一个潜在模型,重点研究将太阳能电力输送到电动汽车充电站的路线设计。本文使用MATLAB和SIMULINK设计一个包含电气控制系统的专用系统,用于改善电动汽车充电端与电池存储系统之间的相互作用,其中电气控制系统协助开发正确的占空比,以便DC/DC变换器稳和调节电压。所实现的电气控制系统在对电网的电能管理和减少EV的充电时间方面有着显著的效果。无论太阳能发电和负载的波动如何,该充电系统始终可以给负载端提供稳的电压。     

一种新型电梯用节能回馈与应急平层供电装置

提出了一种新型电梯用超级电容器节能与应急平层供电装置。该装置可以将电梯重载下行或是轻载上行时产生的势能转化为电能储存起来．并在电动机处于电动工况时作为辅助电源与市电并行供电。这样既减少了电梯运行所需的电能损耗又降低了电动机工作温度．同时在停电时还能作为应急平层供电装置,驱动轿厢就近平层开门。     

基于摩擦热的低压温差发电系统研究

通过实验设计了一套基于摩擦热的低压温差发电系统研究,它是由摩擦热能收集器,半导体温差发电器和散热冷源耦合而成。本装置将温差发电片的贴合在摩擦产生热量的导体上,另外一端连接散热片,以提高电片两端的温差,从而提高发电的电压和电流。并将发出的电通过升压电路升压后为蓄电池充电,蓄电池经稳压模块后可为一些要求不高的用电场合供电,如照明用电等一些低功耗的用电场合。     

蓄电池电解液结冰原因分析

寒冷地区的有些用户反映，装载机使用的蓄电池电解液在冬季有结冰现象，造成发动机无法启动，有的甚至因电解液结冰导致蓄电池壳体破裂。笔者查阅了有关蓄电池的一些资料，结合徐工装载机蓄电池电解液的使用情况，从原理上对蓄电池电解液结冰的原因进行分析，并提出一些预防措施。1蓄电池的有关理论１．１蓄电池的基本原理蓄电池的工作原理就是化学能与电能的相互转化。在外加电场作用下，将电能转化为化学能储存起来的过程叫充电过程；在使用时，将化学能转变为电能供用电设备使用的过程叫放电过程。铅蓄电池的充电过程和放电过程是一种可…     

临近空间大型可移动平台的供电系统关键技术研究

本文研究临近空间大型可移动平台的供电系统方案,分析了基于太阳能电池、蓄电池、超级电容、电能传输母线和供电终端的供电系统架构方案。文中对供电系统中的高压直流电能传输和无线充电等关键技术进行研究。通过对供电系统架构方案及其关键技术的研究,可满足临近空间大型可移动平台的供电需求,实现对平台设备的可靠供电。     

蓄电池室消防对策初探

蓄电池作为一种直流备用电源,通过反复的充电和放电,使化学能、电能相互转换,停电情况下为供电设备提供直流应急电源,维持重要用电设备工作的连续性随着科技发展,各类生产设备生产工艺日益复杂,控制操作程序逐步自动化,对供电负荷等级要求越来越高,蓄电池在工业、电力、电信、金融等行业自动控制及高层、地下建筑的火灾报警、安全疏散上得到了广泛利用。蓄电池的结构及工作原理蓄电池是靠化学作用工作的,它与我们日常生活中使用的电池不同,电池使用是将其积蓄的化学能通过放电转化成电能的过程。而蓄电池不仅可通过放电将化学能转…     

分布式光储互补无线充电系统研究

提出分布式光储互补无线充电系统为电动汽车提供电能,该系统采用分布式光伏发电与储能互补的方式,从根本上解决了电动汽车的清洁问题;同时,采用无线充电的方式替代有线充电,实现了电动汽车全自动化充电过程。从长远来看,分布式光伏储能无线充电系统将是电动汽车的最佳配电及充电选择方式,是无人驾驶和车联网的必然匹配技术。     

室内热湿环境营造系统的热学分析框架

初步构建了该框架.根据室内外温差合理配置传热能力是利用围护结构传热的关键;室温与热源或热汇的温差驱动空调系统的热量传递,选取热源或热汇时在满足热量传递需求的基础上减少各环节的温差消耗是降低系统能耗的问题所在;通过分析各环节温差消耗的影响因素,得到了降低温差消耗的可能途径;讨论了湿度传递驱动力(湿度差)与热量传递驱动力(温差)之间的相互转换.     

地板送风不同送风温差对冷负荷减小系数的影响

利用数值模拟方法对不同送风温差下地板送风系统房间的总热源和单热源进行流场和温度场的模拟,分析了各单一热源冷负荷减小系数的变化规律,模拟结果表明在相同的送风速度下,除了放置于地面上的热源(主机)冷负荷减小系数基本维持在0.81,其它热源的冷负荷减小系数随着送风温差的增大而增大,且分层高度附近的热源冷负荷减小系数受送风温差的影响最大。     

MOV在交直流电压下耐受能力的试验研究

MOV是限压型SPD的核心器件。限压型SPD在各种非正常工作情况下会出现温度持续上升,引发MOV热崩溃后导致SPD故障,严重时会引发火灾事故。利用热稳定试验箱和压敏电阻直流参数仪进行了多组实验,对试验数据进行了对比分析,结果表明:MOV在交直流电压下的耐受能力主要与MOV的热容量(能量吸收能力)和热阻(散热能力)有关;直流电压下MOV功率损耗产生的热量大于交流电压下产生的热量,其主要原因是直流电流下MOV的荷电率高于交流电压下的荷电率。     

24V/5A太阳能控制器设计

近年来再生能源技术广受重视,而太阳能发电由于有先进的电力电子技术辅助,已成为极具潜力的再生能源之一。文章介绍了太阳能电池的基本原理和伏安特性,提供了一套小24V/5A太阳能控制器的电路。该电路将太阳能电池阵列与蓄电池直接耦合,采用低功耗的单片机P87LPC767作为控制回路的核心,实时测量蓄电池的端电压,通过脉宽调制控制太阳能电池阵列的充电电压,并通过功率管控制蓄电池与负载的通断,实现对蓄电池的放电保护。     

Design and development of battery management system (BMS) using hybrid multilevel converter

ABSTRACT

Batteries that are integrated to the renewable system have to bear a wide range of operational conditions such as varying rates of charge/discharge, depth of discharges, temperature fluctuations and so on. When these batteries are connected in series, after several charging and discharging cycles, the voltage and state-of-charge (SOC) imbalance will occur between different batteries. In the proposed topology, the hybrid multilevel converter is used along with auxiliary battery to get constant output voltage during discharging and store excess power during charging. As a result, the voltage and SOC get balanced and also overcharging and discharging can be avoided. The multilevel output is used to improve the performance of the load and battery lifetime.     

水源热泵在低温地热生活热水系统的应用

提出在常用低温地热生活热水系统中增设回水加热器,以回收生活热水系统的排水。对可选的5种回水加热热源———燃煤锅炉、燃油锅炉、燃气锅炉、电锅炉及水源热泵的节能性、经济性进行了比较,提出水源热泵辅助低温地热生活热水系统。结合工程实例,对常用低温地热生活热水系统与水源热泵辅助低温地热生活热水系统进行了经济性比较。水源热泵辅助低温地热生活热水系统可有效降低生活热水系统排水温度及排水量,节能、节水效果显著。     

基于室内排风的热泵型低温地板采暖系统的节能分析

根据我国的气候特点和能源情况,热泵作为一种典型的节能装置,在我国暖通空调领域有着广阔的应用前景。另外为了进行室内排风的热回收,可以采用室内排风热泵系统。而发展热泵供暖系统最有效的供暖方式是低温地板辐射供暖。本文对基于室内排风的热泵型低温地板辐射采暖系统进行了节能分析。     

Electrical analysis of a hybrid photovoltaic-hydrogen/fuel cell energy system in Denizli, Turkey

In recent years, hybrid photovoltaic-hydrogen/fuel cell energy systems have been popular as energy production systems that are clean, environmental-friendly, modular, and independent from fossil fuels. In February 2007, a clean energy research facility consisting of a 5 kWp photovoltaic system and a 2.4 kWp hydrogen-fuel cell system was built to investigate these energy production technologies at Pamukkale University in Denizli, Turkey. In this hybrid energy system, electricity is generated by photovoltaic panels. Generated electrical energy is stored chemically in batteries and metal hydride hydrogen canisters. Hydrogen electrolyzed from water is transformed to DC electrical energy by two fuel cells in the case of its necessity. DC electricity produced by photovoltaic panels and fuel cells is converted to AC by two inverters for the requirements of the building. In this study, an electrical energy analysis of the building, in terms of energy efficiency, harmonics, voltage changes, voltage and current sags, voltage and current swells, transients, power outage, frequency changes etc., is performed to evaluate the power quality of the hybrid energy system. In addition, some measurements such as insulation resistance, loop impedance, line impedance, grounding resistance, and specific resistance of the ground are measured to obtain the electrical characteristics of the system.     

Smart fuzzy-based energy-saving photovoltaic burp charging system

This paper focuses on the optimal usage of photovoltaic energy by implementing ‘pulse charging’ technique to charge batteries and to keep the supply from the solar panel continuously without any interruption. The burp-pulse charging technique is used to supply multiple loads. Three different batteries Bp, Ba1 and Ba2 are smart charged concurrently and individually during three kinds of charge statuses controlled by a charge regulation system. The high-frequency input pulses are obtained from an interleaved flyback converter. The charge for prime battery (Bp) is from the positive pulse and that for auxiliary battery-1 (Ba1) is from the break period between the pulses. Finally the third battery, that is, auxiliary battery-2 (Ba2) is incorporated to utilise the negative pulse charge through an inductor when the step-up chopper is closed. This can otherwise be put as, utilising the discharge current of Bp to supply a load. The Ba2 voltage is stepped up to supply a motor load when supply from prime battery Bp is unavailable. The closed loop simulation introduces a fuzzy logic controller which controls the generation of pulses according to the variations in the input source voltage. By this way, a linear and smoother current is available to charge the batteries. Thus, the energy-saving concept is fulfilled by the proposed design. Faster and uninterrupted charging and better battery life are other facets of the proposed system. The closed loop simulation is performed and results are presented.     

三元锂离子电池直径和荷电状态对热失控传播影响研究

随着我国新能源汽车的不断发展,锂离子电池作为新能源电动汽车最重要的储能设备,由于其能量密度高的特点,存在着燃烧迅速、爆炸并触发相邻电池热失控传递的热安全危险,制约着更规模化的应用和推广,严重威胁着人员的生命财产安全。电池的热失控主要与其电池形状、荷电状态、连接方式等有关。而在不同荷电状态和不同直径的耦合条件下的电池热失控研究是提高锂电池安全性能的研究重点。为了探究锂离子电池热失控传播过程的主要影响机制,采用不同直径（10440型、14500型、18650型、21700型、26650型和32650型）和不同荷电状态（50%、70%、100%）的三元锂离子电池为研究对象,考察其在一维线性排列方式下的热失控传播时间及热失控空间传播速率变化特征,进而深入分析电池直径和荷电状态对热失控传播时间及热失控空间传播速率的影响机制。采用实验数据、传热学理论以及无量纲分析相结合的方法建立了阻断电池热失控传播链的计算模型,进而预判电池间的热失控传播时间,结合无量纲分析得到了不同荷电状态（50%、70%、100%）电池热失控传播时间与电池直径（10,14,18,21,26,32 mm）的特征关系,提出了一维排...     

Energy performance assessment of occupied buildings using model identification techniques

Model identification allows the assessment of energy performance of buildings based on measured data. However, model identification of occupied buildings is difficult because the disturbances introduced by the occupants are usually not measured. For office buildings, we propose a method to estimate the occupancy in function of electrical energy consumption. To determine the complexity of the model, SVD is used for the number of thermal zones and statistical analysis is used for the model order. The estimated model was evaluated by simulation, consistency of input–output behaviour and uncertainty analysis. The RMS of the simulation error is less than 0.7 °C for the training data set. The proposed method allows calculating macroscopic parameters of the building (such as thermal loss and time constants), showing the relative weights for heat losses and estimation of energy savings by heating control.     

Evaluation of a prototype active building envelope window-system

Active building envelope systems represent a new enclosure technology that uses solar energy to compensate for passive heat losses or gains through building envelopes. In ABE systems, energy obtained from solar radiation is converted into electrical energy by using photovoltaic cells. This electrical energy is subsequently used to power a series of solid-state thermoelectric modules, which can control the flow of heat through the enclosure. In order to assess the practical feasibility of ABE systems, we have developed a prototype ABE window-system and an outdoor testing room. A testing system was developed to measure the ABE system's temperatures, solar radiation, current and voltage. Theoretical and experimental results are presented and compared. Finally, the performance of the ABE window-system was evaluated.