基于温度测量法的光伏阵列失效组件监测系统的设计

为了解决光伏阵列电站中的光伏组件由于各种原因产生失效,不能及时发现、维护而导致较大的经济损失问题,提出了一种通过在PV组件接线盒上安装无线温度传感器,动态的监控旁路二极管温度间接监测失效组件的新方法,该方法能够在不影响光伏组件结构的情况下及时发现、定位光伏阵列中失效的光伏组件;文中对热斑效应形成和温度测量法的联系以及异常数据点的处理做了较为详细的阐述,设计了温度采集和无线传输系统的硬件电路,电路简单、可靠,成本低廉易于实现,采集精度符合设计要求;并编写了PC端的的监测系统的程序,通过对PV组件失效进行遮挡验证,结果表明基于温度测量法的光伏阵列失效组件监测系统检测结果可靠温度,易于使用。     

混合储能系统在弱光充电系统中的仿真研究

光伏阵列的输出特性受光照强度影响很大,在弱光下光伏电池的最大功率点跟踪控制算法无法达到蓄电池的充电要求。为了最大限度利用光伏阵歹tl的输出功率,采用超级电容减小光照变化对蓄电池充电的影响。针对独立光伏发电系统的特点,设计了一种有源式混合储能方案,在保证光伏电池获得最大功率跟踪的同时,也能满足蓄电池的充电要求,建立的Simulink／MATLAB仿真模型验证了该设计方案的有效性。     

光伏电池组件隐式、显式单二极管模型准确性对比研究

光伏电池组件非线性输出特性的物理建模及其优化参数的准确提取是光伏发电系统设计计算、性能评估及优化控制的重要前提.相对于传统的隐式单二极管模型,该文在光伏电池显式单二极管模型的基础上利用Lambert W函数推导了光伏组件的显式单二极管模型,提出一种基于重启边界约束Nelder-Mead单纯形算法的参数提取方法rbcNM,并利用两种典型光伏电池组件的实测数据对隐式、显式单二极管模型的准确性进行了对比测试和验证.结果表明:rbcNM算法可以快速准确的提取隐式、显式单二极管模型的优化参数,计算结果与实测数据具有很好的一致性,相对于已有文献在准确度上取得了大幅度的提升;显式单二极管模型的准确性显著高于隐式单二极管模型,对光伏电池组件的电流-电压和功率-电压特性曲线具有更高的拟合精度.     

平板微热管式相变蓄热装置蓄放热特性研究

本文提出一种基于平板微热管阵列的低温相变蓄热装置。该装置以平板微热管阵列为核心传热元件,以月桂酸为相变蓄热材料。搭建实验测试系统对该相变蓄热器在不同空气流量和进口温度的工况下进行蓄放热试验,对蓄放热过程中平板微热管阵列的均温性能、蓄热器内部的温度变化及蓄放热功率进行了实验研究及分析。结果表明;微热管阵列组件在蓄热、放热过程中表现出良好的均温性,工作高效且稳定;相变蓄热装置的实际蓄放热性能优良,平均蓄热、放热功率分别为418 W和353 W。     

自适应遗传算法在光伏发电系统中的应用

针对光伏阵列在受到阴影遮挡时光伏发电系统总功率大幅下降的问题,采用分布式光伏阵列与光伏逆变器的群控方法,通过开关矩阵将多个光伏阵列与多台光伏逆变器相连,形成灵活多变的光伏发电网络拓扑结构,并根据该网络拓扑结构的工作原理,提出了相应的自适应遗传算法来实现分布式光伏阵列与光伏逆变器之间的群控管理.仿真及实验结果表明,光伏阵列受到阴影遮挡时,该算法使得光能的转换效率明显优于常规典型的分布式光伏发电方式,为有效利用光能提供了思路.     

两级式光伏并网逆变器建模与非线性动力学行为研究

本文首先建立了两级式光伏并网逆变器严格的分段光滑状态方程, 分析级联情况下光伏阵列电压对光伏并网逆变器非线性动力学行为的影响, 然后探讨拓展两级式光伏并网逆变器输入电压范围的策略, 并研究前后级电路内部参数变化引起并网逆变器输出电流的快变尺度分岔和慢变尺度分岔现象. 研究发现: 若对光伏阵列电压进行分段控制, 可以有效展宽两级式光伏并网逆变器的输入电压范围; 适当增加前级输出电容值、电感量, 可以避免系统产生混沌运动, 而后级参数的取值需避开多个不连续的混沌区域. 研究结果对提高光伏发电系统的效率与稳定性有较重要的参考价值.     

高效黑硅电池组件反光板角度的模拟研究

传统的光伏组件为了实现发电功率最大化,安装时具有一定倾角,但在使用过程中仍有一部分光会被组件表面反射到空中造成浪费.本文设计了一种带反光板结构的高效黑硅太阳能电池组件,多角度吸光的黑硅组件配合反光板结构可以充分利用反射光线.对反光板和黑硅组件夹角进行了模拟计算,结果表明,当光伏组件安装倾角为34时,反光板安装角度为16.5最佳,同等光照条件下使得电池的发电功率增加了约39%.     

全碳太阳能热光伏系统

太阳能热光伏发电是太阳能利用的重要途径之一。碳纳米材料具有优异的物理化学特性,因此是极具吸引力的太阳能热光伏系统材料。本文提出一种基于碳纳米材料的全碳太阳能热光伏(CSTPV)系统,竖直排列多壁碳纳米管阵列作为吸收器;堆木头结构多壁碳纳米管薄膜作为发射器。堆木头结构使发射器在两种偏振条件下都具有与光伏电池能带间隙匹配的波长选择发射率。本文结合能量平衡模型和等效电路模型建立了可靠的CSTPV系统理论模型,并对CSTPV系统进行表征。当发射器吸收器面积比为3,太阳能聚光倍数为3000时,系统效率达到最大值16.2%,比相同条件下钨发射器太阳能热光伏系统最大效率(12.4%)提高了30.6%。     

面向电容式微机械超声换能器器件的32通道收发 电路设计与测试*

针对以电容式微机械超声换能器(CMUT)阵列为探头的超声成像系统,设计了一种兼具现场可编程门阵列(FPGA)控制、脉冲驱动以及微弱电流信号检测功能的电路。利用FPGA产生64路控制信号,控制脉冲信号的频率、脉冲个数、占空比等参数;脉冲电路在FPGA以及直流电压的控制下,产生32路脉冲信号;接收电路通过跨阻放大结构实现32路电流信号检测;32通道收发电路利用脉冲产生芯片内自带的T/R开关进行高压隔离。通过搭建测试平台,对收发电路功能及一致性进行测试,并连接CMUT进行自发自收测试。测试结果表明,32通道收发电路具有良好的一致性,电路可以实现基于CMUT阵列的32通道超声信号的发射,检测回波信号,并对CMUT器件的带宽进行测试。电路具有功能完善,结构稳定的优点,为基于CMUT阵列的超声成像系统的应用提供了硬件支持。     

基于模型辨识的BP神经网络在光伏系统MPPT中的应用

光伏电池作为光伏发电系统的重要组成部分,研究其模型的准确性并对其最大功率点进行预测与跟踪,对于光伏发电效率的提高具有重大意义。本文首先根据光伏电池的内部结构和伏安特性建立其数学模型,并对所建立的模型进行参数辨识,进而得到模型输出与测量信息偏差最小的参数值,验证模型的准确和有效性。根据模型所反映的规律,将温度和光照强度作为输入变量,最大功率点对应的电压作为输出变量,构建了用于MPPT的神经网络模型。神经网络经训练后对最大功率点电压进行预测与跟踪,结果表明构建的神经网络具有良好的适应性。     

Design and electrical characteristics of a modular plasma torch

A modular system for constructing an atmospheric pressure plasma source is presented and studied. The design and construction of the plasma torch module by modifying and reassembling the structural components of two different models of spark plugs are first described. Each module can produce a torch plasma of 1 cm radius and 6 cm height and having a peak density exceeding 10¹³ cm^-3. A set of modules, each connected in series with a ballasting capacitor in the circuit, can be operated as an array sharing a common power source to produce a dense and large-volume plasma. The electrical characteristics of the module are studied for the case of a single module and two capacitively coupled modules. The discharge can be maintained, with the aid of ballasting capacitors, in a stable diffuse arc. Furthermore, the coupled discharges in an array of modules are operated with the maximum power efficiency as indicated by a near one power factor seen by the power line     

Electronic Equipment Proposal to Improve the Photovoltaic Systems Efficiency

This paper reports a new technique proposal to improve the photovoltaic systems. It was made to design and implement an electronic system that will detect, capture, and transfer the maximum power of the photovoltaic (PV) panel to optimize the supplied power of a solar panel. The electronic system works on base technical proposal of electrical sweeping of electric characteristics using capacitive impedance. The maximum power is transformed and the solar panel energy is sent to an automotive battery. This electronic system reduces the energy lost originated when the solar radiation level decreases or the PV panel temperature is increased. This electronic system tracks, captures, and stores the PV module’s maximum power into a capacitor. After, a higher voltage level step-up circuit was designed to increase the voltage of the PV module’s maximum power and then its current can be sent to a battery. The experimental results show that the developed electronic system has 95% efficiency. The measurement was made to 50 W, the electronic system works rightly with solar radiation rate from 100 to 1,000 W m^− 2 and the PV panel temperature rate changed from 1 to 75°C. The main advantage of this electronic system compared with conventional methods is the elimination of microprocessors, computers, and sophisticated numerical approximations, and it does not need any small electrical signals to track the maximum power. The proposed method is simple, fast, and it is also cheaper.     

双谐振拓扑高压脉冲电容器充电电源

脉冲电容的充电电源是脉冲功率技术中的关键设备,为研究更高精度的高压脉冲电容充电电源,基于一种较为新颖的双谐振拓扑结构,通过推导传递函数,分析了其电压和电流传输特性。根据双谐振电路存在两个谐振点的特性,提出基于双谐振变换器的充电电源充电方式,即充电阶段采用串联谐振工作模式,到高压保持阶段通过频率调制降低开关频率至接近第二谐振点,实现对脉冲电容自放电压降的动态补偿,从而保证高压充电电源充电精度的同时,极大地提高脉冲电容的高压稳定度。为验证所提出方式的可行性,基于Matlab/simulink搭建仿真模型,分别对串联谐振全桥变换器和双谐振全桥变换器两种拓扑结构进行仿真,实验结果验证了所提出双谐振拓扑的频率调制方式的可行性。     

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The charging characteristic of the capacitor charging power supply was analyzed with practical series resonant topology. The method that setting two current taps and regulating PWM switching frequency was putted forward with close loop controlling algorithm to charge the multi-group capacitor banks with constant current. A capacitor charging power supply with the max output current 6.5A and the max output voltage 2000V is designed. Experimental results show that, this power supply can charge the four capacitor banks to any four different voltages in 1 minute with charging accuracy less than 1%, and meet the requirements of J-TEXT ohmic field power system.     

FANTM: First Article NIF Test Module

Designing and developing the 1.7- to 2.1-MJ power conditioning system (PCS) that power the flashlamps of the main and power amplifiers for the National Ignition Facility (NIF) lasers is one of several responsibilities assumed by Sandia National Laboratories (SNL) and Maxwell Physics International in support of the NIF Project. The NIF is currently being constructed at Lawrence Livermore National Laboratories (LLNL). The test facility that evolved over three years to satisfy the project requirements is called the First Article NIF Test Module (FANTM). It was built at SNL and operated for about 17000 shots to demonstrate component performance expectations over the lifetime of NIF. A few modules are used initially in the amplifier test phase of the project. The final NIF system requires at least 192 modules in the four capacitor bays. The paper briefly summarizes the final design of the FANTM facility and compares its performance with the predictions of circuit simulations for both normal operation and fault-mode response. Applying both the measured and modeled power pulse waveforms as input to a LLNL amplifier gain code indicates that the 20-capacitor PCS can satisfy the NIF requirement for an average gain coefficient of 5.00%/cm and can exceed 5.20%/cm with 24 capacitors     

Study of the static characteristic I-V and the electrical parameters corresponding to the shunt resistance Rsh and series resistance Rs per unit area of a solar cell with grain size

This paper presents a new technique based on the junction recombination velocity (Sf: junction recombination velocity) at the grain size for the evaluation of the series and shunt resistances. The study of the response of the solar cell and the parameters of recombination in grain size, which are the object of the investigation, is related to the study of the static characteristic I-V and electrical parameters Rs and Rsh under a magnetic field. This study has allowed us to address some of the theoretical aspects of the field solar cell in order to draw a conclusion and some perspectives. Based on the results obtained for the photocurrent density and the photovoltage, we will study the I-V characteristic of the solar cell to then be able to propose a model for the determination of the shunt resistance Rsh and the series resistance Rs. Series resistance investigations, including numerical simulations and field data tests, are conducted to examine the energetic behavior of the PV modules for efficiency. Experimental results show that the proposed direct resistance-estimation method allows the PV modules to achieve their maximum power and efficiency under various operation conditions.