一种具有充电功能的交直流转换电路的设计与实现

介绍了一种具有充电功能的交直流转换电路的设计方法,分别对交直流转换电路、直流电压转换电路和电池充电电路进行设计。实际应用表明:在有220V(AC)或电池的情况下,电源都可以稳定输出24、12、3.3V直流电压。     

火灾自动报警系统直流供电线路电压损失研究

工业企业的火灾自动报警系统确认火灾发生后,联动开启消防报警设备,警示、引导、组织现场作业人员疏散。直流24V电源供电线路延长后,线路上的电压损失导致直流24V电源供电消防报警设备出现了延迟动作、动作不稳定与拒动作的情况。本文结合工程举例,针对直流24V电源供电线路的电压损失,从直流供电线路设计与直流供电技改进行分析,并提出了工程解决方案。     

充电截止电压对锂离子电池化学性能的影响

主要研究了不同截止电压对锰酸锂离子电池的放电容量性能、工作电压和恒流/恒压充电容量等电池性能的影响,结果表明:对于锰酸锂材料锂离子电池,放电容量、中值电压和稳定电压都随着充电截止电压的升高而提高,电池的充电截止电压只要不低于4.15 V,电池放电容量损失就不会超过6%;当充电截止电压为4.15 V时,电池的恒流充电容量占总充电容量的85%以上,与4.20 V相比变化不大。这一结论为牺牲小部分容量、提高电池的安全性能设计提供了实验依据。     

焊接触电事故的原因分析及防范措施

我国国产电焊机电源为220／380V工频交流电电源,其空载电压为55-90V。焊工常常带电进行更换焊条、调节焊接电流、清理工件等操作,再加上电焊机和电缆室外工作受风吹、日晒、雨淋、粉尘的腐蚀等影响,绝缘层易老化变质,容易出现漏电现象。因此,电焊操作中极易发生触电事故。     

钛板为负极载体的酸性二次电池性能研究

在国内首次自组装了以Pt／C气体扩散电极为正极,Ti板为负极材料的新型酸性锌空气电池,进行了新电池性能测试。结果如下,实验以电流密度为20mA／cm。来恒流充放电,首次放电压平台在0．92V,充电平台在2．65V左右,充电电压在不断上升,可能是由于氧气析出后破环了Pt／C电极结构引起;在新型锌空电池的锌负极表现出优良的性能,在整个电池性能改变时,锌负极的沉积与溶出所需电压基本维持稳定状态,实验进行了七个循环,显示出酸性锌空气电池是可行的。     

LX88系列累积计时器

LX88系列累积计时器是深圳新安龙兴电子厂的产品。这种计时装置计时准确,工作可靠,使用交流220V、36V、24V、12V、6V、3V或直流24V、12V、6V、3V、1.5V等各种电源。主要用于工业设备、电力、特种机械、化工环保、理化试验及产品例试等场合下,连续或间断性工作进行累积计时,考核实际工作时间,提供时间依据。主要技术性能及参数: (1)显示方式:五位字轮显示,其中前四位为整数小时,末位小数时。     

变压吸附电磁阀控制回路改造

<正>1存在的问题山东晋煤明水化工集团有限公司明泉化肥厂现有1套145 kt/a处理能力的变压吸附装置,运行2年后,现场电磁阀出现不能准确开闭的问题。现场测量发现:部分电磁阀阀端控制电源电压降低到16 V左右(24 V控制电源),因控制电源电压较低,导致阀门不能准确动作,使生产系统受到影响。该套变压吸附装置共有170多只电磁阀,安装时选用的1.5 mm2电源线,DCS控制柜到现场     

聚丙烯装置低压配电间母联备自投程序的优化

某30万t/a聚丙烯装置低压配电间母联备自投功能由LOGO!24RC PLC实现,但在运行中发现原程序存在设计缺陷,当一段进线电源失电时,LOGO!24RC PLC程序缺少检测另一段进线电源电压正常工作的环节,母联就执行自投功能,容易扩大事故范围。针对该问题,对母联备自投逻辑程序进行优化,并对优化程序进行仿真调试。     

辅助变压器式软开关电镀电源的设计

研制了零电压零电流开关电镀电源,其超前臂实现了零电压开关,滞后臂实现了零电流开关.通过采用辅助变压器网络,在原边施加一个与环流电流方向相反的电压,使环流电流迅速衰减到零;并且阻断环流电流的反向通道,使原边电流保持为零,实现了滞后臂的零电流开关.试验结果表明:系统工作正常稳定,其输出电压可在0～12 V可调,输出电流最大可达1 000 A,大大改善了功率开关器件工作环境,降低了开关损耗,提高了工作效率和电镀质量.     

电解法生产硫酸亚锡工艺研究

研究了锡电解生产硫酸亚锡的过程，考察了电解电压，外冷却和电解液浓度等对电解过程的影响，提出了用反向脉冲充电来消除电极表面钝化现象，通过实验得到以下优化工艺条件：电解电压１．５Ｖ，电流密度５００Ａ／ｍ＾２，反向脉冲充电间隔０．５ｍｉｎ／４０ｍｉｎ，电解液ＳｎＳＯ４浓度１００ｇ／Ｌ。     

Simulative Approach for Linking Electrode and Electrolyte Properties to Supercapacitor Performance

Supercapacitors as energy storage devices show distinct advantages like high power density and high cycle stability. While in current applications, mainly the high power density is leveraged, future non‐mobile storage devices could also benefit from the robustness and materials employed, while lower charging/discharging time constants are acceptable. In this study, a simulative approach is employed to investigate the complex interplay of mass transfer, electric losses, double layer capacitance for different electrode thicknesses, electrode and electrolyte conductivities as well as charging/discharging time constants. Within the simulation cyclic voltammetry, galvanostatic cycling as also electrochemical impedance spectroscopy experiment could be realized, showing the dependency of achievable maximum capacitance and voltage efficiency on various properties.     

大容量、智能化高速换向脉冲电镀电源的研究

本电源以逆变器技术和斩波器技术为主要手段,以大功率半导体自关断器件为主开关电器件,按控制电解槽电流和槽压两个档次分别单独采用闭环反馈ＰＷＭ实时控制方式,并由微机软件构成智能化输出的电流、电压流形变换和宽范围的脉冲参数调节系统。     

浅谈电动机的启动方式

电动机是工矿企业最常用的用电设备,为了电动机在启动过程中不引起母线电压下降,影响其他设备的正常运行,我们在设计过程中应尽量使用降压启动方式。电动机降压启动方式有很多种,例如全压直接启动、自耦变压器起动、星一三角起动、软起动器启动、变频器启动等。文中将——阐述,根据生产过程的需求正确选择电动机类型,功率、电压等级及其启动...     

Heat generated during electrochemical double-layer capacitor “self-discharge”

Eight commercial 10F electrochemical double-layer capacitors (EDLCs) were connected together and placed in a container filled with mineral oil. The whole system was placed into a Dewar container. Temperature variation and heat exchanged between the test EDLC and the environment during its charging, discharging, and “self-discharge” were measured, together with voltage U changes. Charge separation during charging was equivalent to a transition into a more ordered system, which results in entropy decrease, while discharging caused entropy increase (the Peltier–Seebeck effect). Consequently, a number of charging/discharging cycles led to a corresponding series of entropy and temperature changes. The final shape of temperature versus time curve during charging/discharging cycles was due to overlapping of irreversible Joule–Lenz and reversible Peltier heats. When charged EDLC was kept under the open-circuit condition, measured heat flow was negligible in comparison to energy loss calculated from potential drop, assuming that energy E accumulated is proportional at any time to voltage to the second power (i.e., E ~ U ²). The result was interpreted assuming that the EDLC “self-discharge” phenomenon is not associated with energy loss by the device, but rather with charge redistribution between EDLC particles characterized by different time constants.     

HC900系统在液氯装置上的应用

介绍HC900系统在液氯装置中的应用,通过对液氯工艺的分析,建立了数学模型,实现了液氯生产及充装的自动控制。     

高精度数控直流稳压电源的设计与实现

基于单片机AT89S51设计了一种高精度数控直流稳压电源,数控部分采用12位高精度D/A转换器TLV5616控制稳压电路的输出电压;采用12位高精度A/D转换器TLC2543测量输出电压;采用矩阵式键盘作为电压的设定装置;采用LCD1602型液晶显示屏显示设定的电压和实际输出电压;电源以电压串联反馈式稳压电路为基础,并在系统中设计了过流保护电路。     

复杂件滚镀光亮铜锡工艺的改进

以某羧酸盐的水溶液作为走位剂(即覆盖能力促进剂),可提高形状复杂的小零件滚镀光亮铜锡时的走位能力。改进后的镀液配方及工艺参数为:CuCN10～20g/L,游离NaCN12～24g/L,SnCl20.5～1.0g/L,Na2HPO490～100g/L,明胶0.1～0.2g/L,走位剂25～35mL/L,温度45～55°C,pH10.5～11.5,电压8～9V,电流300～350A/桶,以电解铜板为阳极。     

膨胀石墨/石蜡复合相变材料的导电及发热特性

采用混合搅拌方法制备膨胀石墨（EG）/石蜡复合相变材料,测试分析了EG含量、施加电压与EG/石蜡复合相变材料体积电阻率的关系,研究了直接自发热和正温度系数（PTC）电阻发热时复合相变蓄热单元的发热特性。结果表明,随着EG含量或施加电压的增大,复合相变材料体积电阻率逐渐减小;施加电压对样品体积电阻率的影响与复合相变材料中EG含量有关,EG含量越高,施加电压对复合相变材料体积电阻率的影响越明显。当施加电压为4.0V时,EG质量分数分别为4%、5%、8%的复合相变材料体积电阻率分别只有0.5V时的0.481倍、0.185倍、0.068倍。基于复合相变材料导电特性,直接负载电压可实现复合相变材料电热转化和相变蓄热;结合PTC电阻发热可灵活控制复合相变蓄热单元加热功率,实现其快速充热。     

20 V stack of aqueous supercapacitors with carbon (−), titanium bipolar plates and CNT‐polypyrrole composite (+)

A 20 V stack of 19 supercapacitors was fabricated from titanium bipolar plates (150 × 150 × 0.1 mm³) coated on each side with carbon nanotubes and polypyrrole composite (+) and pigment carbon black (?), and microporous polymeric separators containing aqueous KCl. Internal sealing of each cell in the stack was achieved by placing a silicone rubber washer between neighboring bipolar plates. The stack was tested by high voltage cyclic voltammetry, galvanostatic charging and discharging, and electrochemical impedance spectroscopy. It approached 25 kW/kg in maximum specific power and 3.64 Wh/kg in specific energy. Performance of the stack through intermittent charging‐discharging tests in a storage period of 10 months (still ongoing) remained fairly stable. For example, it exhibited almost zero decay in capacitance after 1000 continuous galvanostatic charging‐discharging cycles in the first month of storage (10 V), and less than 6% loss in the seventh month (19 V). © 2011 American Institute of Chemical Engineers AIChE J, 2012