ADI新的双向电平转换器能在多种电源电压系统中实现无缝数据传输

美国模拟器件公司(Analog Devices,Inc.,简称ADI)最新推出首款数字开关系列产品——ADG3308,它允许用一片集成电路(IC)提供双向的数据传输和电平转换。因为它的8个通道允许同步读和写混合操作以及双向数据传输,所以这种新的总线开关超过需要分立的读和写周期的传统总线开关,从而为设计工程师提供更大的使用灵活性和工作效率。ADG3308的先进集成电路也减少了设计工作量并且节省了印制电路板(PCB)面积。

低电压数字系统电源设计技术

讨论低电压数字系统电源的三种设计技术——低压差线性稳压器、电感开关型DC/DC转换器和电容电荷泵型DC-DC转换器;分析它们各自的特点和应用范围,介绍DC/DC转换器的发展趋势。

低电压电源系统的发展趋势

过去的十年时间里，大多数电子设计人员都逐渐放弃了集中式供电方式，电路板上的砖式DC/DC电源转换器提供了更为灵活的解决方案，现在，这种方法又正在被基于中间总线结构的电源输送系统所代替。

基于ZigBee无线网络的电源电压监控系统

针对当前传感器网络普遍采用的有线连接方式的布线不便、灵活性不高的缺点,提出了一种基于ZigBee无线网络的实时监控系统的实现方法。介绍了利用CC2430芯片搭建系统硬件平台的方法和各节点协议栈的软件设计过程,最后介绍了使用LabWindows/CVI制作上位机界面。最终实现了利用无线网络对电源的监控。实验证明,该系统能够采集ZigBee无线传感器网络内节点的电源电压即时数据。

Power swing and voltage collapse identification schemes for correct distance relay operation in power system

The new techniques were presented for preventing undesirable distance relay maloperation during voltage collapse and power swings in transmission grids. Initially, the work focused on the development of a fast detection of voltage collapse and a three-phase fault at transmission lines by using under impedance fault detector (UIFD) and support vector machine (SVM). Likewise, an intelligent approach was developed to discriminate a fault, stable swing and unstable swing, for correct distance relay operation by using the S-transform and the probabilistic neural network (PNN). To illustrate the effectiveness of the proposed techniques, simulations were carried out on the IEEE 39-bus test system using the PSS/E and MATLAB software.

Modeling of electrode system for three-phase electric arc furnace

To simulate the process of electrode operation, a dynamic model describing the electrode system of three-phase electric arc furnace was developed. This new model can be divided into three submodels in terms of the practical situation. They are the power supply system model the electric arc model and the hydraulic actuator system model. According to the basic circuit theory, the power supply system model where the high voltage transmission circuit and mutual inductances were considered, was set up. The electric arc model, which was novel for the electrode control, served as the electrical load and was connected to the power supply system model. The hydraulic actuator system model consists of the proportional valve part that is modeled to capture the dead-zone nonlinear characteristics and the hydraulic cylinder part where the impact of the load force is taken into account. By comparing simulation data and actual data, the results show that the electrode system model is proved to be accurate.

Flexible Control of Pulsed Power for Biomedical Applications Using PC

This work aims to control pulsed power for biomedical fields, which demands sensitive parameters. The pulsed power consists of a voltage rise time of less than 50 ns and charging energy to 1.0 J/pulse; also, the pulse control area includes pulse interval pulse shot number, output voltage. To achieve this system, a pulsed power system exists including software running on PC, universal serial bus （UgB~ for connection, and FPGA controller. Using the software for complex control of pulsed power will enable expansion into various fields with easy operation.

Norton equivalent circuit for current control loop of grid-connected system

Modeling method for the current control loop of a grid-connected PWM inverter with the LCL output filter was discussed.Firstly,the current control loop with the LCL inverter-side current as feedback was established.Then,parameters of PI controller were calculated on the basis of an equivalent controlled object.Finally,Norton equivalent circuit for the current control loop of grid-connected system was derived by integrating one control equation,which connected the PWM inverter output voltage and the LCL inverter-side current,with two circuit equations,separately using the LCL inverter-side current and the injected current as loop currents.With the induced Norton equivalent circuit,system-level resonant and unstable issues on real grid-connected system applied in weak distributed power systems can be easily analyzed.The validity of substituting Norton equivalent circuit for grid-connected system is verified by simulation and experiment.

Modern Electrical Power Source on New System of Dissipation and Renewable Energies Sources

This paper presents some solutions of modem renewable energy system applied actually in dissipation energy source： wind turbine, solar panel battery charge, SSS （support set system）, and standby diesel generator cooperated in series, parallel and hybrid system with main energy system. Its solution enable obtain independent individual energy source in different work exploitations. One of problems concerned with alternative energy source is changes of output voltages and output power dependence of climatic conditions. Possible solution is application of decoupled adjustable speed generation system in renewable energy generation. The decoupled generation system consists of： alternative energy source, internal combustion engine drives permanent magnet generator and DC/AC, or AC/AC converter. Performance of single decoupled generation set is discussed supported by results of laboratory tests. To provide high quality voltage is applied an additional energy storage, made from super capacitor and bidirectional DC/DC convert. Such system performs very stiff voltage in any load condition. Integration of solar battery panels or renewable wind energy system is provided via DC link of the variable speed decoupled autonomous generation system. Results of computer simulation and laboratory experiments are presented in the paper.

Optimum Energy Harvesting for Series-Connected Power Sources with Uniform Voltage Distribution

This paper presents a power system architecture where SIPO （series-input parallel-output） converters are controlled to achieve uniform inpt voltages across their respective series-connected power sources while also tracking the system optimum power point; the system optimum power point is the maximum power drawn from the series-connected power sources while their voltages are kept uniformly distributed. With proper uniform input voltage distribution control, near maximum use of the power sources is achieved by employing only one MPT （maximum power tracking） controller instead of multiple MPT controllers dedicated for their respective power sources. Provided that the maximum power point voltages of the input power sources are similar, the resulting system architecture offers near-maximum power transfer with a lower parts count. A feasibility study using computer simulation has successfully validated two SIPO power architectures and their control concepts for optimum power transfer.

Reliability Investigation of PCs＇ SMPSs

Today reliability is one of the serious requirements of electronic systems. The numbers of system failures, repair cost, guarantee, etc. are estimated by reliability estimation. In this paper reliability of a switching power supply, which is used for personal computers, is evaluated. It will show that the most of failure rates depends on power circuit because of more stresses and dissipations. Derating effect of devices on the failure rate is discussed. A prototype power supply＇s waveforms are used for stress detection and calculation of dissipations.

Research on the control method for voltage-current source hybrid-HVDC system

The hybrid-HVDC topology,which consists of line-commutated-converter(LCC)and voltage source converter(VSC)and combines their advantages,has extensive application prospects.A hybrid-HVDC system,adopting VSC on rectifier side and LCC on inverter side,is investigated,and its mathematic model is deduced.The commutation failure issue of the LCC converter in the hybrid-HVDC system is considered,and a novel coordinated control method is proposed to enhance the system commutation failure immunity.A voltage dependent voltage order limiter(VDVOL)is designed based on the constant DC voltage control on the rectifier side,and constant extinction angle backup control is introduced based on the constant DC current control with voltage dependent current order limiter(VDCOL)on the inverter side.The hybrid-HVDC system performances under normal operation state and fault state are simulated in the PSCAD/EMTDC.Then,system transient state performances with or without the proposed control methods under fault condition are further compared and analyzed.It is concluded that the proposed control method has the ability to effectively reduce the probability of commutation failure and improve the fault recovery performance of the hybrid-HVDC system.

Self-powered electrochemical anodic oxidation： A new method for preparation of mesoporous Al2O3 without applying electricity

Anodic oxidization （AO） is one of the most important methods available for fabricating mesoporous Al2O3 , which can be conducted at either high potential or low potential; however, the need for an external electricity power source limits its applications. In this work, a novel self-powered electrochemical anodic oxidization （SPAO） system was introduced for preparing mesoporous Al2O3 , by using newly-invented triboelectric nanogenerator （TENG） arrays driven by wind power. Using the controllable voltage output of the TENG arrays, the SPAO system was shown to regulate the pore depth and pore size of the mesoporous Al2O3 . In contrast to traditional AO systems, this technique takes advantage of the high output voltage of TENG arrays without any additional energy costs. In addition, the SPAO system can be used for the preparation of other mesoporous materials.