周期电气信号测量中软件同步采样方法的研究

软件同步采样是周期电气信号微机测量中最常用的采样方式,但它采样的同步精度和时间间隔均匀程度都不够高,影响测量精度.通过对软件同步采样实现过程的分析,找出了影响采样同步和导致采样间隔不均匀的主要原因,并提出了三个相应的解决方法.方法一是在采样过程中动态调整采样时间间隔,使实际采样时刻最大限度地逼近理想均匀同步采样时刻;方法二是在采样后用线性插值方法修正采样值,使实际采样序列逼近理想的均匀同步采样序列;方法三是实时跟踪测量信号周期和校正采样周期.三种方法均具有计算量小,易于实现,实用有效的特点.对电功率和谐波测量的仿真分析结果,证实了所提方法对提高微机测量精度的有效性.     

GPS同步采样装置中防止干扰GPS秒脉冲信号的措施

为削弱和消除干扰对基于GPS同步采样装置的影响,在简要介绍GPS同步采样装置的基础上,根据秒脉冲总是位于2 s交界处的特点,提出了防止干扰GPS秒脉冲信号的软硬件措施。其中,软件鉴别法简单可行,适用于CPU内部资源充足的情况下;而硬件措施节约了CPU的片内资源,适用于CPU负担较重的应用场合。试验结果表明,该方法可有效地克服干扰信号对GPS同步采样装置的影响。     

基于混合量测状态估计的配电网故障定位方法

微型相量测量单元(micro-phasor measurement unit, μPMU)为配电自动化的进一步升级提供了良好的量测基础,但现阶段电网中μPMU数量有限,难以满足传统配电网故障定位的需求。针对该问题,结合电网中μPMU与智能电表等量测设备,并基于虚拟节点的多重状态估计方法,提出了一种基于混合量测状态估计的故障定位方法。首先,通过等效变换将μPMU和智能电表的测量信息输入到故障状态估计器当中。然后,利用μPMU将网络划分为不同的区域。根据状态估计结果计算故障电流,缩小故障搜索区域以减少计算复杂度。为了识别区域内的故障位置,通过设置附加虚拟故障节点形成多种特定的故障拓扑结构并执行多重状态估计,计算出用于识别故障位置的加权测量残差指标,以确定故障位置。最后,在实时仿真系统(real-time digital simulation, RTDS)中进行仿真测试,结果表明所提方法在不同故障场景下均能准确有效地定位故障,且对量测误差具有较好的鲁棒性。     

超宽带脉冲信号的一种频域采样和接收方法

对纳秒级的超宽带脉冲信号进行采样需要设计采样速率高达数十GHz,且必须具有较低功耗的超高速模数变换器,提出了一种频域模数变换的方法,使超宽带脉冲信号通过一个频域滤波器组,并采用一组低速模数变换器在频域对脉冲信号并行采样,大大地降低了接收机对前端模数变换器采样速率的要求。并给出了频域同步、频域信道估计和频域解调的设计算法,计算机仿真结果证明了在能够大大降低采样速率的情况下,频域采样超宽带脉冲通信接收机具有和传统时域高速采样接收机相近的误码率性能。     

电网工频信号非整周期采样误差分析

交流信号采样过程中存在着很多误差源,非整周期采样是一种重要的误差源,由于电网频率的波动,实际工程应用中整周期采样难以实现,用非整周期交流采样测量正弦信号的有效值和有功功率的大小,存在着比较大的测量误差。本文从时域角度对其研究,推导非整周期采样时域误差公式,建立非整周期交流采样测量电压电流信号有效值和有功功率的误差数学模型,分析每个参量变化对同步误差影响的大小,找出主导因素,为减少测量误差提供理论依据。     

A feature extraction method for the signal sorting of interleaved radar pulse serial

In this paper, a new feature extraction method for radar pulse sequences is presented based on structure function and empirical mode decomposition. In this method, 2-D feature information was constituted by using radio frequency and time-of-arrival, which analyzed the feature of radar pulse sequences for the very first time by employing structure function and empirical mode decomposition. The experiment shows that the method can efficiently extract the frequency of a period-change radio frequency signal in a complex pulses environment and reveals a new feature for the signal sorting of interleaved radar pulse serial. This paper provides a novel way for extracting the new sorting feature of radar signals. Translated from Journal of Harbin Institute of Technology, 2006, 38(1): 130–133 [译自: 哈尔滨工业大学学报]     

一个实用电声脉冲法的空间电荷测量系统

空间电荷的测量对于电介质材料的研究有重要的意义。本文介绍了与日本学者联合制作的用于平板型试品的电声脉冲法即PEA法空间电荷测量系统。在介绍了系统的原理和硬件结构以及相应的重要参数之后,对于使用该套系统对高密度聚乙烯试品进行的一些试验结果进行了介绍和分析。结果表明,高密度聚乙烯的微观形态影响其空间电荷积聚特性,总的来说,结晶度越小,越有利于空间电荷的积累。试验证明,该套系统可以较好地完成空间电荷分布的测量。     

蓄电池组单个电池电压测量方法

蓄电池组单元电池测量面临电压高、点数多和生产成本难控制等问题,一般情况下难以准确对单个电池进行精确测量。通过对实际生产和测量电路性能的详细分析,提出了一种基于串联电阻分压法再加标定步骤的新方法。     

A parallel prefiltering approach for the identification of a biased sinusoidal signal: Theory and experiments

The problem of estimating the amplitude, frequency, and phase of an unknown sinusoidal signal from a noisy‐biased measurement is addressed in this paper by a family of parallel prefiltering schemes. The proposed methodology consists in using a pair of linear filters of specified order to generate a suitable number of auxiliary signals that are used to estimate—in an adaptive way—the frequency, the amplitude, and the phase of the sinusoid. Increasing the order of the prefilters improves the noise immunity of the estimator, at the cost of an increase of the computational complexity. Among the whole family of estimators realizable by varying the order of the filters, the simple parallel prefilters of orders 2 + 2 and 3 + 3 are discussed in detail, being the most attractive from the implementability point of view. The behavior of the two algorithms with respect to bounded external disturbances is characterized by input‐to‐state stability arguments. Finally, the effectiveness of the proposed technique is shown both by comparative numerical simulations and by a real experiment addressing the estimation of the frequency of the electrical mains from a noisy voltage measurement. Copyright © 2015 John Wiley & Sons, Ltd.     

冲击脉冲型探地雷达等效采样方法的研究

提出一种对探地雷达回波信号这种高频率的信号进行采集的方法,即等效时间采样方法．并设计实现了等效时间采样的具体电路,包括产生步进采样脉冲的高精度步进系统、采样门电路等,通过实验证明该方法的有效性。     

A virtual instrument for determining basic parameters of sinusoidal signals in stationary modes

A virtual instrument is proposed for determining the frequency, amplitude, and initial phase of sinusoidal signals of voltage and current, as well as the angle of phase shift between the voltage and current, that is created in the LabVIEW development environment. Comparative analysis of errors of the proposed instrument and the standard virtual instrument Extract Single Tone Information VI from the LabVIEW package was performed, which has shown that the proposed instrument determines the signal parameters more accurately than the standard one if the signals are exposed to industrial noise and interferences.     

An algebraic continuous time parameter estimation for a sum of sinusoidal waveform signals

In this paper, a novel algebraic method is proposed to estimate amplitudes, frequencies, and phases of a biased and noisy sum of complex exponential sinusoidal signals. The resulting parameter estimates are given by original closed formulas, constructed as integrals acting as time‐varying filters of the noisy measured signal. The proposed algebraic method provides faster and more robust results, compared with usual procedures. Some computer simulations illustrate the efficiency of our method. Copyright © 2016 John Wiley & Sons, Ltd.     

基于自适应滤波的信号分离与窄带干扰抑制

变电站复杂的电磁环境有时会对变电站电气试验工作产生干扰。基于对干扰信号的分析,讨论了自适应滤波器的基本原理,围绕最小均方误差准则以及最小均方(LMS)算法,设计了一种自适应信号分离器,并基于自适应信号分离器研究了低频窄带干扰抑制,利用快速傅里叶分解(FFT)进行了频域分析,进而实现了窄带干扰抑制,研制了一种变电站用电磁环境净空间生成装置。实验仿真结果验证了所提设计的可行性和装置的有效性,南京地区220 kV以上变电站的现场试验表明,基于该方法研制的变电站用电磁净空间生成装置能可靠抑制干扰信号,有效提升试验效率。