一种新型回路电阻测试仪的研究与设计

针对传统低压回路电阻测试仪只能在被测设备停电时使用的一大限制,本文提出并设计了一种新型低压回路电阻测试仪。该仪器可在低压设备运行状态下对其回路电阻进行测量,在保证测量精度的前提下减少了设备停电率,大大提高了工作效率。     

低压直流供电电路中高压直流的产生

在由低压直流电源供电的电路中,往往电路的某些部位需要使用高于电源所供的电压,将电源所供的低压转换为较高的电压,常用的方法有3种:自举升压、电感升压、逆变升压。结合实际应用电路对各种升压方法从器件选择、升压原理、升压结果等诸方面进行分析、探讨,解决了总体供电电压不变时,局部高压产生的关键性问题。它对电子电器电路的设计人员有一定的启发作用,对优化电路、遴选器件有较强的参考价值。     

济钢120t转炉二次烟气除尘设计

济钢120t转炉二次烟气除尘设备选用长袋低压脉冲除尘器,风机采用液力偶合器,并设计将加料系统除尘风量直接加入转炉二次烟气除尘系统。系统投产后,每炉钢节电1200kW,烟气排放浓度为47mg/m3,烟气温度在110℃以下。实践证明,该系统具有节能、捕集率高、排放浓度低、自动化程度高等特点。     

Parallel feedforward class-AB control circuits for low-voltage bipolar rail-to-rail output stages of operational amplifiers

A new family of class-AB control circuits for bipolar rail-to-rail output stages of operational amplifiers is presented. Step by step, we report the development of five simple class-AB control circuits showing the advantages of using parallel feedforward. The circuits have been designed in such a way that temperature, supply voltage and process parameters have little influence. To test the output stages, one of them has been implemented in a very simple two-stage operational amplifier on a semi-custom chip. Measurements show a bandwidth of 2.5 MHz, a gain of 40 dB, a quiescent current of 23µA and a maximum output current of 250µA. Simulation results of three other simple operational amplifiers with the new class-AB control circuits are shown, which have a higher gain and maximum output current.     

采用磁集成技术的低压大电流DC/DC变换器的仿真

运用回转器一电容模型可以很好的理解磁性器件，特别是复杂的集成磁件。文章运用磁导电容类比建模法建立了磁件的回转器一电容模型。在回转器一电容模型中，磁路由容性电路来模拟，绕组由双端口的回转器来代替。进行了采用磁集成技术的低压大电流DC／DC变换器的仿真。仿真电路拓扑是原边不对称半桥、副边倍流整流电路。磁集成变压器的结构是Wei Chen提出的原边绕于中柱的只在侧柱开气隙的倍流整流磁集成结构。建立了用SPICE语言描述的回转器仿真模型。仿真软件是MULTISIM2001。     

光伏发电接入对配电网低压台区线损的影响

随着可再生能源的不断开发,越来越多的光伏发电接入配电网,而光伏发电的不稳定性会对配电网的稳定造成影响。为此,针对光伏发电对配电网低压台区线损的影响,建立了电源接入模型并进行了仿真计算。     

Event-driven,pattern-based methodology for cost-effective development of standardized personal health devices

Experiences applying standards in personal health devices (PHDs) show an inherent trade-off between interoperability and costs (in terms of processing load and development time). Therefore, reducing hardware and software costs as well as time-to-market is crucial for standards adoption. The ISO/IEEE11073 PHD family of standards (also referred to as X73PHD) provides interoperable communication between PHDs and aggregators. Nevertheless, the responsibility of achieving inexpensive implementations of X73PHD in limited resource microcontrollers falls directly on the developer. Hence, the authors previously presented a methodology based on patterns to implement X73-compliant PHDs into devices with low-voltage low-power constraints. That version was based on multitasking, which required additional features and resources. This paper therefore presents an event-driven evolution of the patterns-based methodology for cost-effective development of standardized PHDs. The results of comparing between the two versions showed that the mean values of decrease in memory consumption and cycles of latency are 11.59% and 45.95%, respectively. In addition, several enhancements in terms of cost-effectiveness and development time can be derived from the new version of the methodology. Therefore, the new approach could help in producing cost-effective X73-compliant PHDs, which in turn could foster the adoption of standards.     

制备工艺和添加剂对TiO2体系陶瓷的复合功能特性的影响

TiO2体系复合功能陶瓷是一种兼有压敏功能和介电性能的新型功能陶瓷材料,具有压敏电压低、非线性系数高、介电常数大等优点,在微小型电子设备与器件中有广泛的用途。本文从制备工艺、添加改性等方面分析了TiO2体系复合功能陶瓷的研究现状,并对其发展方向进行了展望。     

三相光伏发电系统在小型低压配网中的应用研究

研究了光伏电池的数学模型,采用扰动观察法实现在光照变化时的最大功率跟踪.将多组光伏电池串并联,通过boost升压电路连到三相逆变器的直流侧,逆变器的交流侧通过LC滤波器直接连到电网.三相逆变器采用PQ解耦的控制策略,在Matlab/Simulink中建立其详细模型.研究三相光伏发电系统在0.4kV小型低压配网中的应用,分析了低压配网在并网和孤岛运行时的功率电压特性,验证了这种应用的可行性.     

基于量测数据质量的低压台区拓扑识别结果可信度评价

在没有先验拓扑连接关系的情况下,基于数据分析法的低压拓扑识别准确率无法量化评估.为此从数据分析法所需的量测数据质量着手,提出了一种根据高级量测体系(AMI)量测质量评价出数据分析法识别结果可信度的方法.首先,通过剖析基于二次规划的数据分析法的工作原理,推导数据质量对识别准确率的影响机理.其次,从数据完整性、数据差异性和数据时间尺度3个方面出发,建立与识别准确率关联的数据质量评价模型,量化了所需数据的质量.然后,以数据质量评价分数和相应的拓扑识别准确率为训练样本,搭建可根据AMI量测质量评价出数据分析法识别准确率范围的模型.最后,以中国广东省3个典型低压台区的数据构建测试集,验证了所提模型的有效性和实用性.