基于MATLAB/SIMULINK的电压波动及闪变测量研究

以国际电工委员会(IEC)推荐的闪变测量原理框图及设计规范为依据,讨论了系统框图中各环节的传递函数,并利用双线性变换法,将各模拟滤波器变换为数字滤波器,研究了电压波动及闪变测量的数字化计算方法.最后利用MATLAB/SIMULINK软件搭建了仿真模型,对电压波动分量、瞬时闪变视感度S(t)及短时间闪变值Pst进行测量.仿真结果符合IEC闪变测量精度要求,为进一步构建电压波动及闪变测量仪提供一定的理论基础.     

基于MATLAB／SIMUUNK的电压波动及闪变测量研究

本文以国际电工技术委员会（IEC）推荐的闪变测量原理框图及设计规范为依据,首先讨论了系统框图中各环节的传递函数,然后利用双线性变换法,将各模拟滤波器变换为数字滤波器,并研究了电压波动及闪变测量的数字化计算方法。最后利用MATLAB／SIMULINK软件搭建了仿真模型,对电压波动分量、瞬时闪变视感度S（t）及短时间闪变值Pst进行测量。仿真结果符合IEC闪变测量精度要求,为进一步构建电压波动及闪变测量仪提供了一定的理论基础。     

电压波动与闪变的测量方法研究

为了简化电压波动与闪变的测量过程,避免国际电工委员会(IEC)推荐的测量方法中的多次滤波运算,利用LabWindows/CVI虚拟仪器开发平台,实现了基于快速傅里叶变换的电压波动与闪变测量。给出了测量软件的流程图和用户操作界面,并对测量结果进行了误差分析。通过与国际电工委员会推荐的测量方法对比,证实了此测量方法是一种准确、简便、实用的离散化计算方法。     

动态闪变电压检测及电机智能自启动系统设计

为迅速准确地提取闪变电压的特征值,克服电压闪变对生产造成的损失,设计了一种智能自启动防护系统.该系统通过对闪变跌落电压实时性检测方法的分析,运用"abc-bq"变换的检测算法,检测出闪变电压波动起止时刻和有效值.同时,系统对闪变电压跌落造成的生产设备停机可以实行自动恢复或报警,为连续性生产工艺提供了一种有效的防护.     

交流电压下电力设备绝缘计算机检测方法

提出了一种新的交流电压下电力设备绝缘计算机检测方法 ,并阐述了这种方法的测量原理、采样数据处理方法。     

航空设备端口信号测试技术研究

从测试端口信号分析设备功能的实际工作中,总结出测试工作的步骤、方法和要点.叙述了从端口测试大电流、高电压、模拟信号和数字信号的方法;研究出从两台设备之间的连线上测出信号流向的技术,给出了用于指示该流向的电路.基于端口信号测试,可分析出设备的性能,完成功能替代研制,实现进口设备的国产化.     

基于DB小波变换的多频时变电压闪变检测仿真研究

电压波动与闪变是评价电力系统电压质量的重要参数,因此电压闪变的检测分析对于电力系统的运维至关重要。为了验证Daubechis(DB)小波变换在电压闪变检测方面的有效性与可行性,采用MATLAB搭建了电压闪变信号模型,采用DB小波变换对多频时变电压闪变信号的检测进行了仿真分析,并将仿真结果与基于平方检测法的仿真结果进行了比较。结果表明,DB小波变换不仅能够检测出电压闪变分量的幅值与频率信息,而且能够根据小波变换的模极大值确定电压闪变发生与结束的时刻,而基于平方检测法的电压闪变信号检测无法直接分离出多个电压闪变分量,也无法检测出电压闪变的起止时刻。仿真结果验证了DB小波变换用于电压闪变检测的有效性与可行性。     

航天器地面供配电设备接口设计技术

航天器地面供配电设备必须要确保供电控制的可靠和测量的准确。概述了该设备的基本组成和功能，对设备和航天器之间的控制信息、状态信息和测量信息的接口设计技术作了较详细地论述，并且结合有代表性的示例给出了参考电路图和说明。     

闪变FFT检测算法的误差分析及修正

快速傅里叶变换(FFT)是在实际应用中测量闪变最常用的一种算法, 但是传统的快速傅里叶变换算法对于测量含多个调幅波所引起的闪变结果与国际电工委员会(IEC)推荐的测量闪变的方法相比不够准确, 存在比较大的误差。为了准确测量闪变, 提出了一种基于改进的快速傅里叶变换算法。以单频率调幅波和双频率调幅波为闪变检测输入信号, 对FFT法检测闪变的各实现环节与IEC方法进行对比分析, 发现FFT检测算法所得的瞬时闪变值与IEC所得的瞬时闪变值有一定的差距, 从而找出FFT检测法的误差来源, 通过修正瞬时闪变值来达到准确检测的目的。通过MATLAB仿真分析可以看出, 基于改进FFT的闪变检测结果与IEC法基本一致, 达到IEC闪变测量精度要求。该检测方法实现简单, 并且可以拓展应用于含三个及以上的调幅波的闪变检测。     

基于ARM和FPGA的线阵CCD测径系统的设计

设计了一种基于ARM微处理器LPC2214与线阵CCD的在线动态测径仪,该测径仪采用FPGA实现对线阵CCD时序脉冲的驱动;以ARM微处理器为测径仪的核心,实现图像信息的处理和对整个系统的控制,保证动态、实时、准确的测量线缆直径.介绍了该仪器的基本原理,详细给出了系统硬件方案和软件流程.     

Flicker visibility and related visual discomfort in 3‐D displays with LED backlight

Abstract— In this paper, the perception of flicker in time‐sequential or field‐sequential 3‐D LC TVs driven by LED backlights is described. The seriousness of the perceived flicker and its influence on visual discomfort is investigated for various backlight operational modes. Results show that display backlights presenting different temporal light distribution have significant contribution to flicker visibility and visual discomfort. The display dimension, 2‐D or 3‐D, affects visual discomfort but not flicker visibility. The relationship between visual discomfort and flicker visibility is proportional when rendering 2‐D images, but not in the case of 3‐D images. Finally, a simple model is presented to evaluate visual discomfort related to flicker in 2‐D rendering.     

A design method for flicker‐free liquid crystal display panels based on indium‐gallium‐zinc‐oxide thin‐film transistors

This paper proposes a design method to reduce the flicker of liquid crystal display panels based on indium‐gallium‐zinc‐oxide (IGZO) thin‐film transistors (TFTs). The proposed design method employs a human factor model to convert the flicker measured at low frame frequency (F _FRAME) to a modification value of the measured flicker (MVMF ) having a frequency sensitivity of flicker, which can distinguish between no blinking and weak blinking. To investigate the causes and characteristics of flicker, the frequency component and increase factor of flicker are analyzed using the checkerboard and solid images. The increase factor in flicker is examined using IGZO TFTs with different antenna ratios (AR s) that cause the variation in threshold voltage of IGZO TFT. To verify the proposed design method, two test panels are implemented with asymmetric and symmetric AR s. The MVMF s of the 15 Hz component at a low F _FRAME of 30 Hz show that the solid image with a symmetric AR has an MVMF of ?62.9 dB, which is improved by 24.3 dB compared to that with an asymmetric AR . Therefore, the proposed method is applicable for a flicker‐free liquid crystal display panels at a low F _FRAME.     

Intercross scanning control with double driver for micro-LED display

This paper proposes a control chip for micro-light emitting diode (μLED) applied on real-time display system. The μLED control system has the video transmitter and the LED display matrix. The transmitter includes interface control, memory management, image format conversion. For LED display unit, we present the intercross scanning, memory management, PWM output controller, gamma correction for LED brightness control. TheμLED display is controlled by the intercross drivers to reduce the flicker and promote the sweeping speed with two FPGA controllers, where two parallel SPI data is adopted. The micro LED components are mounted on a PCB with mass-transfer techniques successfully. The FPGA controller can drive about 10 k light-emitting diodes with 12-bit colors for displaying system with PWM method. The passive-matrix micro LED (PMLED) driving can achieve 384 refresh rates with 50 MHz clocking frequency. The experiments result low flicker achieved, which the SVM index is only 1.5 with a photometer measurement.     

Ka频段飞行器测控与通信系统设计

传统基于S频段的统一载波测控通信系统受工作频率低、占用频带窄的特点限制,无法满足现代及未来飞行器测控与通信系统对于高速数传、通信带宽、安装空间、克服“黑障”及抗干扰性等方面日益增长的需求,提出一种Ka频段直接序列扩频体制的飞行器测控与通信系统以解决上述问题;利用Ka频段频带宽、空间选择性好、减小“黑障”影响等特点,同时采用直接序列扩频通信体制实现遥测、外测和遥控等不同功能点频统一和信道统一,简化系统结构、减小设备体积;介绍了系统架构及主要设备组成,阐述了基带数据综合设备、Ka频段一体化终端设备等单机的详细设计及天线的选择,并给出了地面测试系统方案;该系统具备体积小、频带宽、扩展性好等特点,可满足未来飞行器测控与通信系统的设计与应用需求。     

An adaptive generation method for electrophoretic display driving waveform design

Electrophoretic display (EPD) technology is attractive when used for reading devices such as e‐paper because of its paper‐like appearance. EPD driving is more complex than other display technologies such as liquid crystal display or organic light emission diode because the driving result of a pixel strongly depends on the initial display state. The particle size and distribution in the EPD film may vary, even if the initial state is the same. Therefore, the display devices vary between different manufacturing batches. Furthermore, different display modes such as videos, pictures or documents need different driving waveforms to achieve an optimal result. EPD manufacturers need to build a customized driving waveform for every manufacturing batch. This is very inconvenient if new applications on EPD are to be developed. And the workload is huge. In this work, an adaptive method is described for automatically creating EPD driving waveforms to fit different conditions. The central idea of this method is generally adjusting the driving time and the voltage state after getting the feedback from a measurement model. In this method, a new driving waveform is used to reduce refresh time and visual flicker. The experimental results show that the proposed approach can automatically and adaptively generate an EPD driving waveform with reasonable quality.     

基于光电传感器的液位检测方法与装置

针对液位检测中液面气泡的干扰问题,提出一种基于双光电传感器和动态阈值的液位检测方法与装置。分析了该液位检测方法的基本原理,阐述了该光电液位检测装置的结构和测试过程。经过实验与数据分析,结果表明：该光电液位检测方法简单实用,具有较高的精度,在待测液体液面有大量气泡情况下检测精度仍可达0．2mm,特别适用于液面易产生气泡液体的液位检测。     

基于云计算的智能测试保障体系构建

针对当前武器装备系统复杂以及测试保障难度大的问题,提出基于云计算的装备智能测试保障体系。该体系以云化智能测控网及运行其上的人工智能算法组成的云计算平台为基础,结合装备的自主保障流程,设计一种基于认知的智能测试与保障方法,实现装备的智能测试与自主保障。基于认知的智能测试以装备的测试性设计为前提,包含机内测试和机外测试两种方式,其运行原理相同,通过云化智能测控网,依托云计算,对获得的历史数据和实时数据进行自组织学习,实时调整装备测试机制、数据传输机制和数据分析与故障预测机制,为实现装备的自主保障提供智能决策支持。     

光电码盘技术在尾矿库高程测量中的应用

干滩高程测量是矿山企业尾矿库监测系统中一项重要的检测内容,用于检测矿山尾矿(废料)排放湖面的高度。尾矿库一般都地处偏远山区,要求检测设备具有很强的恶劣环境适应能力,因而迫切需要开发出一种新的测量技术,以用于满足数字化矿山建设的需要。光电码盘计数测距法就是为了满足这项实际需求而研发的。文章介绍了此项技术的工作原理、电路实现方法,并对波形处理、精度控制、数据处理等几方面也做了详细的阐述。     

两阶段设备维护策略选择的灰靶决策模型

针对设备的最佳维护策略选择问题,首先提出6种设备运维目标,同时给出两阶段设备运维策略选择的加权智能灰靶决策模型的架构图以及建模算法流程;然后采用德尔菲调查法与层次分析法相结合确定不同目标的权重.结合某半导体面板制造企业的设备运行现场实际数据,对于成本型目标和适中型目标,分别采用相应的效果测度函数计算出设备在不同运行状态下的一致效果测度矩阵以及综合效果测度矩阵.通过运用两阶段设备维护的灰靶决策模型,最终得到设备不同状态下的最佳维护策略.所提出方法对正确选择半导体面板设备维护策略、提高设备运维效率、降低维护成本具有实际指导意义.     

An artificial neural network method for remaining useful life prediction of equipment subject to condition monitoring

Accurate equipment remaining useful life prediction is critical to effective condition based maintenance for improving reliability and reducing overall maintenance cost. In this paper, an artificial neural network (ANN) based method is developed for achieving more accurate remaining useful life prediction of equipment subject to condition monitoring. The ANN model takes the age and multiple condition monitoring measurement values at the present and previous inspection points as the inputs, and the life percentage as the output. A function generalized from the Weibull failure rate function is used to fit each condition monitoring measurement series for a failure history, and the fitted measurement values are used to form the ANN training set so as to reduce the effects of the noise factors that are irrelevant to the equipment degradation. A validation mechanism is introduced in the ANN training process to improve the prediction performance of the ANN model. The proposed ANN method is validated using real-world vibration monitoring data collected from pump bearings in the field. A comparative study is performed between the proposed ANN method and an adapted version of a reported method, and the results demonstrate the advantage of the proposed method in achieving more accurate remaining useful life prediction.