改进型双馈风力发电机最大功率点跟踪策略

针对传统双馈风力发电机最大功率点跟踪极值搜索策略将正弦信号作为搜索信号而很难将正弦信号从总的输出信号中区分出来的问题,提出了一种利用风湍流作为极值搜索信号的改进型最大功率点跟踪策略。该改进策略对叠加风湍流的叶尖速比和功率系数进行傅里叶变换,获得相位差信息,从而确定叶尖速比变化方向,使双馈风力发电机达到最佳运行工作点。仿真结果表明,该改进策略可控制风力发电机转速较好地跟踪风速变化,实现了额定风速以下运行区域的最大风能捕获。     

半导体温差模块在热缺陷监测中的应用

通过对变电站运行设备大电流回路连接点发热原因及环境的分析,提出了一种利用半导体温差发电模块结合充电泵和升压型DC-DC变换电路,以单片机测温电路为负载,采用间歇工作的方式为现场测温电路提供电源。重点解决了在半导体温差发电模块输出电压不稳定、压差较小时,DC-DC变换器超低压启动的难题,并结合实际应用环境对现场独立供电和测温装置的组成以及工作方式做了进一步探讨。     

一种穿戴式系统电源控制器设计与实现

设计了一种穿戴系统电源控制器,是基于单片机控制的电源控制器,为穿戴式系统提供电源管理功能。具有双电池的充电/供电管理,内置单片机,电源开关软控制,并可遥控关机,可实时监控并指示控制器各工作状态,可指示电池电量信息,与上位机通信上传工作状态及电池电量等信息。具有充满保护、过流保护、短路保护、输入反接保护、双电池并接工作等保护功能。具有效率高、体积小、操作简单、功能全、双电池配置灵活、金属外壳电磁兼容性好、可靠性高等优点。可以用太阳能电源或手摇发电机通过控制器给电池充电,提高其野外使用适应性。     

Maximum power point tracking (MPPT) system of small wind power generator using RBFNN approach

A novel approach of combination of radial basis function neural network (RBFNN) and particle swarm optimization (PSO) is proposed to achieve the maximum power point tracking (MPPT) in this study. The measured data of the small wind generator (250 W), including wind speed, generator speed and output power of wind power generator, are applied to estimate the wind speed and output power by the proposed wind speed ANN_wind and power estimation ANN_Pe-PSO modules, respectively. Using the predicted results by the two modules of Matlab/Simulink, the MPPT point can be obtained by manipulating the generator speeds. The experimental results show that the proposed RBFNN-based approach can increase the maximum output power of the wind power generator even if the wind speed and load varies.     

Pervasive power: a radioisotope-powered piezoelectric generator

A long-lasting radioisotope micropower generator for self-powered sensor microsystems promises to make pervasive computing systems more reliable. Its higher energy conversion efficiency enables microsystems with small amounts of radioactivity to realize sensor and basic computation operations. The goal is to achieve power sources that operate over a wide temperature range and for extended time periods with high reliability. To reach this goal, researchers have investigated technologies for miniature micropower applications and developed radioisotope power generators. We've created a power source employing radioactive thin films and piezoelectric unimorphs, using a nonthermal energy conversion cycle that enables much higher energy conversion efficiency.     

Simulation of a steam generator leak detection experiment in the CCTL

A simulation study to predict the response of leak detectors in the CCTL (Core Components Test Loop) experiment at the Argonne National Laboratory was carried out. A mathematical model was developed for the sodium-water interaction and the subsequent distribution o f the reaction products in a liquid metal steam generator loop. The detectors and the appropriate instrumentation were also modeled and their response to a series o f designed experiments was calculated. The simulation program and the specific CCTL leak detection experiment will be used to identify parameters o f importance for leak detection in LMFBR. Preliminary experimental results show good agreement with the theoretical predictions.     

On the size of critical graphs with small maximum degree

In this paper, we give some new properties of edge chromatic critical graphs, and give new lower bounds for the average degree of Δ-critical graphs with Δ=11, 12 by the use of these properties.     

Experiments in adaptive power control for truly wearable biomedical sensor devices

Emerging body-wearable devices for continuous health monitoring are severely energy constrained and yet required to offer high communication reliability under fluctuating channel conditions. Such devices require very careful management of their energy resources in order to prolong their lifetime. In the earlier work the authors had proposed dynamic power control as a means of saving precious energy in off-the-shelf sensor devices. In this work the authors experiment with a real body-wearable device to assess the power savings possible in a realistic setting. The authors quantify the power consumption against the packet loss and establish the feasibility of dynamic power control for saving energy in a truly-body-wearable setting.     

Three-dimensional texture generator supervised by a small number of parameters

In this paper we give a method for generating surface appearances with a maximum number of 15 supervising parameters. Surfaces are made up of fast spatial changes (high spatial frequencies) and slow spatial changes (low spatial frequencies). The generator is a mixture of several techniques generally used in image synthesis, image animation, in CAD and in signal processing. A model for generating fish scales is actually under development. The flexibility of the method makes it suitable for many other applications, such as 3D regular patterns, tissue-like texture, etc.     

碳纳米管薄膜气流热电发电机性能测试分析

基于碳纳米管薄膜的热电特性,设计了一种新型的薄膜式气流热电发电机。当热气流在碳纳米管薄膜材料表面流动时,在薄膜平面内形成温度梯度,通过塞贝克效应将热能直接转换为电能。利用浮动催化化学气相沉积法制备了导电性较好的透明碳纳米管薄膜,建立了气流热电发电机实验模型,对其输出电压进行了测试。实验表明:与传统的固定热源热电发电机相比,该气流热电发电机的输出电压较高。提出了集流体动力、流固耦合换热、热电效应于一体的多物理场耦合发电机制,对该实验结果进行了解释。碳纳米管薄膜气流热电发电机容易集成加工,可解决微光机电系统的电源问题,具有广阔的应用前景和实用价值。     

降低最大距离测试码输入功耗研究

伪随机测试在数字系统的故障测试中已经得到了多年的应用,但传统的伪随机测试存在着效率比较低的缺陷。针对该缺陷提出了在伪随机测试方法中引入测试码之间距离的概念。根据测试码之间距离越大,能检测到不同故障的数目概率也越大的假设,基于测试码之间距离的随机测试法（简称基于距离测试法）可以生成一组测试码序列。但是由于基于距离测试法所生成的测试码相邻间距离的变大,将造成相邻输入码之间的跳变次数增多,使得输入测试码时所需要的功耗急剧增大。针对该情况,提出对伪随机测试法生成的测试码输入顺序进行重新排序和调整的概念,从而达到降低测试功耗的最终目标。     

Automatic feed control of steam generator in the power unit of a nuclear power plant: Modeling and optimization

The paper presents the mathematical model of automatic feed control in the power unit of a nuclear power plant (NPP). As initial data for model design, archival information about industrial process in the power unit is used. We obtain the transfer function of a shaping filter for random signal generation with a required autocovariance function. The results of simulation studies and optimization of automatic control system’s parameters using a genetic algorithm are produced.     

Multimodal interaction with a wearable augmented reality system

An augmented reality system enhances a mobile user's situational awareness and provides new visualization functionality. The custom-built multimodal interface provides access to information encountered in urban environments. In this article, we detail our experiences with various input devices and modalities and discuss their advantages and drawbacks in the context of interaction tasks in mobile computing. We show how we integrated the input channels to use the modalities beneficially and how this enhances the interface's overall usability.     

Optimal control of generator resynchronisation in electric power systems

Optimal control techniques are discussed for the resynchronisation of a steam turbine unit in an electric power system after it has lost synchronism. A time optimal control is derived and the resulting bang-bang control law is first simulated on an analogue computer and then implemented on a physical generator in a model power system. Aspects of implementation on a full scale power system are discussed, and the proposed controller is shown to be quite general and applicable to all turbine generators and systems.     

Evaluation of suitable locations for the installation of solar thermoelectric power plants

The aim of the present paper is to determine the best location to host a solar thermoelectric power plant. We will seek to show how Geographic Information Systems (GIS) and Multi Criteria Decision Making (MCDM) such as the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS method) and Analytic Hierarchy Process (AHP), are an excellent combination to solve complex locations problems. The coast of the Region of Murcia in the southeast of Spain has been chosen as the study area to carry out this evaluation.The GIS will be shown to be a very useful tool, since GIS are able to generate a database which serves as a starting point for conducting any decision support system. The posed problem will be resolved using restrictions to reduce the area of study, and the criteria that will influence the decision-making. These criteria will be of different natures; with quantitative criteria (numerical values) coexisting with qualitative criteria (labels and linguistic variables). In this article, AHP will be used to obtain the weights of the criteria, and the fuzzy TOPSIS method for the evaluation of the alternatives. In order to compare the results obtained with TOPSIS, the ELECTRE-TRI methodology will be applied.     

Improving power network stability and unit stress with adaptive generator control

The ‘steady state stability’ of the French power transmission system has been greatly improved by supplying additional signals to the voltage regulator. The control system parameters, including the additional signals, have been chosen in order to cover all the possible operating conditions and network configurations. These additional signals lead to an increase in the ‘steady state stability’ domain even with a regulator having constant parameters. Better results have been obtained using the model reference adaptive control method with an adjustable regulator. A method based on the ‘hyperstability’ approach has been used for the design of the adaptive control system because of its efficiency. Moreover, the adaptive control of generator excitation, using voltage, speed and active power as input signals, reduces the oscillations of the H.P. turbine valves when the generator is affected by network perturbations. Therefore, the wear of the units, in particular of nuclear units, could be reduced. The principles of this new type regulator are discussed and experimental results are presented.     

Robust control of electric generator in the case of time-dependent mechanical power

The problem of control of electric generator whose model is described by a third-order differential algebraic equation with a priori unknown parameters under uncontrollable external disturbance defined by an unknown time-dependent power is solved. When the problem is solved, it is assumed that the relative speed of the generator’s rotor can be measured. A control algorithm ensuring small amplitude of the rotor vibrations in the quasi-steady-state mode due to changes in the voltage at the excitation coil of the rotor is proposed. This algorithm also ensures the stable operation under emergency conditions caused by changes in the reactive resistance of the power transmission line. Numerical examples and the results of computer simulation are presented to illustrate the performance of the proposed control algorithm.     

A small sample comparison of maximum likelihood, moments and L-moments methods for the asymmetric exponential power distribution

Three methods of estimation, namely maximum likelihood, moments and L-moments, when data come from an asymmetric exponential power distribution are considered. This is a very flexible four-parameter family exhibiting variety of tail and shape behaviours. The analytical expression of the first four L-moments of these distributions are derived, allowing for the use of L-moments estimators. A simulation study compares the three estimation methods in small samples.     

光伏系统最大功率跟踪方法的研究及其仿真

在分析光伏阵列的数学模型和输出特性的基础上,提出了自适应扰动控制算法。对该算法进行了理论分析,建立了光伏系统的仿真模型,并在Matlab/Simulink环境下进行仿真。仿真结果表明,系统能够快速地跟踪到最大功率点,在光照强度突变的情况下也能快速追踪到最大功率点,具有较好的控制性能。     

风力发电机实验测试系统的设计与实现

设计了一种可同时测试多个参数,功能综合的风力发电机测试系统。分析了两种A/D芯片与DSP的连接电路,在系统前端对待测的高电压与高电流进行信号调理,实现A/D芯片与DSP芯片之间并行的连接方式。利用DSP定时器中断来触发A/D芯片进行数据采集,同时利用CPLD控制A/D芯片同步采样。采用内部软件滤波,要求滤除干扰的奇次谐波,实验结果证明滤波效果明显。