大规模容差模拟电路多故障诊断法

本文研究了大规模容差模拟电路的多故障诊断问题,针对交流、直流线性电路和非线性直流电路,考虑了测试点数目有限以及元件容差存在的情况下的电路故障诊断,采用了一种基于线性程序概念的子网络级故障诊断算法来确定元件的实际参数是否在容差范围内或者某些元件是否有故障.文中提及的几个测试方程在定义可能的故障元件中起了关键性作用,并详细阐述了二重故障的诊断原理,且给出了三重故障的诊断公式.该方法大大减少了大规模网络故障诊断计算量,快速有效的定位故障元件.最后用实例说明了该法的有效性.     

A generalized fault diagnosis method in dynamic analogue circuits

Fault diagnosis of analogue circuits is essential for analogue and mixed‐signal systems testing and maintenance. A new method is proposed in this paper for multiple fault diagnosis of linear analogue circuits in frequency domain. The Woodbury formula is applied to the modified nodal equation to construct the fault diagnosis equation, which relates the limited measured circuit responses with the multiple faults inside the circuit in a linear way. A recently developed ambiguity group locating technique is modified here to identify the faulty parameters directly. Computation cost is reduced compared to combinatorial search in traditional fault verification methods. Only one node is needed for voltage measurement, but multiple excitations on accessible nodes are required for fault identification. Parameter evaluation can provide the exact solution to the deviated values of faulty parameters. The faulty parameter deviations can have any finite values. Example circuits are provided to illustrate the proposed method. Two other methods for multiple analogue fault diagnosis sharing the same mechanism as the method proposed in this paper are also briefly described. The proposed method is extremely effective for the circuit with very limited accessible nodes and is also computationally efficient. Copyright © 2002 John Wiley & Sons, Ltd.     

A method for fast simulation of multiple catastrophic faults in analogue circuits

The paper offers an efficient method for simulation of multiple catastrophic faults in linear AC circuits. The faulty elements are either open circuits or short circuits. The method exploits the well‐known Householder formula in matrix theory to find the node voltages deviations due to the perturbations of some circuit elements. The main achievement of the paper is a systematic method for performing the simulation of all combinations of the multiple catastrophic faults. The method includes two new procedures enabling us to find very efficiently the node impedance matrix of the nominal circuit and inverses of some matrices corresponding to different fault combinations. The procedures are the crucial point of this approach and make it very efficient. Consequently, the amount of the computing power needed to carry out all the simulations is significantly reduced. Numerical examples illustrating the proposed approach are provided. Copyright © 2008 John Wiley & Sons, Ltd.     

Nullator-norator approach to analogue circuit diagnosis using general-purpose analysis programmes

In this paper a decomposition approach to diagnosis and fault prediction in large analogue and switched capacitor circuits is proposed, reduced to an analysis of the corresponding nullator-norator models at a single test frequency. Algorithms for isolation of faulty nodes and subcircuits are presented. the topological conditions for performing diagnosis of faulty nodes and for identification of faulty elements have been considered. the element tolerance variations and measurement errors have been taken into account. the possibilities of the general-purpose programmes for frequency and worst-case analysis have been used in the practical implementation of diagnosis and fault prediction. Diagnosis of benchmark circuits has been performed and the results of a computer simulation using the programme PSpice are presented.     

Multiple catastrophic fault diagnosis of analog circuits considering the component tolerances

This paper deals with the diagnosis of multiple catastrophic faults, being cuts (open‐circuits) of some connecting paths and/or short‐circuits of some pairs of points in analog circuits. A method enabling us to detect and identify the faults, taking into account the deviations of the circuit parameters within their tolerance ranges, is developed. The method exploits an appropriate fault dictionary. The fault dictionary is used only for preliminary identification of the faults, because it is based on the analysis of the circuits with nominal parameters. The crucial point of the method is a verification procedure, proposed in this paper, based on the linear programming approach. It leads to the results considering the component variations within their tolerance ranges. In addition, a procedure for selecting appropriate test points, employing some evolutionary techniques, is developed. Although the approach presented in this paper is described in detail for linear circuits, it can be directly generalized to nonlinear circuits. Three numerical examples, including two linear and one nonlinear circuits, illustrate the proposed method and show its efficiency. Copyright © 2011 John Wiley & Sons, Ltd.     

基于小波分形分析和脊波网络的模拟电路故障诊断方法

提出了一种新型的脊波网络方法来进行模拟电路的故障诊断,这种系统化的方法采用小波分形分析、主元分析和数据归一化作为数据预处理器来进行故障响应信号的预处理,采用脊波网络进行故障元件的分类,并采用主元分析方法选择脊波网络隐层脊波元的数目。仿真结果表明,提出的诊断系统能有效地实现模拟电路的故障诊断,不但能有效地诊断模拟电路的单故障情况,还能诊断多故障情况。     

Multifrequency approach to fault diagnosis

This paper deals with multiple-fault diagnosis for linear analogue circuits. the proposed approach is based on multifrequency measurements of some voltage (transfer function) at the accessible output port and can be used for multiple-fault location. It uses certain algebraic invariant properties of the transfer function with respect to the set of faulty elements. Computationally this approach reduces checking the problem of multiple-fault diagnosis to one of the existence or non-existence of a common solution of two systems of linear equations; this amounts to the finding of the rank of a matrix. These linear equations are derived via symbolic representation of the measured voltage (transfer function) accessible for measurements. A numerical example of the application of such an approach is given.     

一种针对分段线性模型的改进型CCM故障诊断方法

针对非线性模拟电路的故障诊断,提出了一种改进型CCM诊断方法：先建立电路的分段线性化模型,分别在各分段区域内列写CCM故障诊断方程,再通过去除CCM方程中的不敏感元件的影响,降低诊断方程的维数,最后通过计算所有区域的诊断特征值以得到诊断结果。这种方法结合了分段线性模型和CCM诊断方法的优势,减少了CCM诊断方程的运算代价,提高了CCM诊断方法的应用价值。实验证明采用这种方法后在保证诊断准确率不变的前提下效率有明显提高。     

A method for fault diagnosis in linear electronic circuits

A method for fault location and parameter identification in linear AC and DC circuits with limited accessible terminals for excitation and measurement is developed in this paper. Fault location is based on a derived relationship having a general meaning. It requires analyses of the circuit with nominal parameters and distinct excitations as well as measurements of some node voltages in the circuit with perturbed parameters. The fault parameter is identified using a formula obtained on the basis of the Woodbury expression. A decomposition technique is suggested enabling us to apply the method for multiple fault diagnosis. Several numerical examples illustrate the proposed approach and show its effectiveness. Copyright © 2000 John Wiley & Sons, Ltd.     

Fault modeling on complex field using least‐square circle fitting for linear analog circuits

A new fault modeling method using least‐square circle fitting (LSCF ) for linear analog circuits is proposed in this paper. In this method, Monte Carlo simulation is used to obtain the output voltage values when the parameter of one faulty component is changed while those of the other components vary within their tolerance limits. All the output response voltage values for every faulty circuit statue are decomposed into real and imaginary parts on a complex field. Then, LSCF method is adopted to match these data, yielding a corresponding circular curve on complex plane, which also can be expressed with a circular function. Its center coordinates and radius are established as the fault features. During measurements, by calculating the distance from one real output to each circular center coordinate and comparing the distance with each circular radius, a faulty component can be diagnosed. The effectiveness of the proposed approach is verified by experiments. The results show that (i) the proposed fault modeling can accurately locate the fault component, and (ii) it can also simply be a fault dictionary. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

基于多目标线性规划的模拟电路软故障诊断方法

阐述了一种新的容差条件下基于多目标线性规划理论的模拟电路软故障诊断方法。通过灵敏度分析建立电路测试节点电压增量方程,并以元件参数变化量与标称值的百分比作为故障判据。采用多目标线性规划方法求解测试节点方程组来估算电路中各元件在一定故障情况下的参数变化百分比,将方程组的解与各元件容差范围相比较来定位故障元件。仿真结果表明,该方法兼顾故障元件的定位和故障元件参数变化量的估算,可以有效地实现模拟电路元件参数在一定容差范围内变化条件下的软故障诊断。     

基于开关变位信息的电网可疑故障元件集识别方法

根据现有的电网故障诊断过程,提出在建立系统元件的开关变位次序图的基础上,采用变位开关附近的改进深度优先搜索法确定停电区域。通过计算变位开关的拒动级别将可疑故障元件依故障概率的大小按顺序排列,进一步提高了故障诊断速度。对开关变位信息在传输过程中发生畸变的情况进行了分析,给出了相应的停电区域搜索步骤。对于电网的单一故障、多重故障以及存在保护和开关多次不正确动作的严重故障,该方法均能快速准确地定位停电区域,并给出精简后的可疑故障元件集。     

容差模拟电路软故障诊断的神经网络方法

为了提高诊断容差模拟电路软故障的速度与准确性,提出了一种随机算法、灵敏度分析、免疫遗传算法与神经网络相结合的软故障诊断方法.该法首先利用基于随机算法的灵敏度分析来解决电路发生软故障时测试节点与激励信号频率选择困难的问题,然后对待测电路施加所选的激励并在所选择的测试节点处提取节点电压,这些电压值再经主元分析与归一化处理作为故障特征,输入神经网络.为了解决传统BP算法本身固有的易陷入局部最优等缺点,引入免疫遗传算法来进行优化,形成基于免疫遗传算法的BP神经网络,进行故障分类.本文详述了其诊断原理及诊断步骤,并通过电路诊断实例,验证了所提方法的有效性.     

基于神经网络的线性电路故障诊断非线性L1范数优化方法

本文提出了一处新的模拟电路故障诊断非线性Ｌ１范数优化方法。在Ｂａｎｄｅｒ Ｌ１范数优化方法基础上增加辅助变量即将电路不可及节点电压增量做为辅助优化变量,构造一个新的故障诊断非线性约束Ｌ１范数优化问题,由一次是优化过程理到的解定位最可能故障元件;     

模拟电路的融合智能故障诊断

提出了一种基于遗传算法、神经网络、模糊集理论与数据融合技术相结合的模拟电路故障诊断新方法。该法使用多类电路测试数据来解决由于测试节点不足而带来的故障信息欠缺等问题，采用遗传算法来优化BP网络的结构与初始权值分布。对每类测试信息各用一个独立的所提遗传神经网络进行初步诊断，得到基于各类测试信息的被诊断电路属于不同故障状态的可能性。在充分考虑每个神经网络输出信息重要程度的基础上，采用模糊积分融合方法进行决策融合。文中研究了其故障特征提取、样本选择、诊断系统结构、学习算法及其综合决策方法，并通过电路诊断实例，阐述了该方法的具体实现，验证了所提方法的鲁棒性。诊断结果表明：所提方法对容差模拟电路的多故障与单故障诊断均适用，故障定位准确率高。     

基于智能信息融合的模拟电路故障定位方法

针对模拟电路故障诊断中存在的测试信息不足、故障定位准确性较低等问题,提出了一种应用智能信息融合技术的模拟电路故障定位方法.该法首先分别采用可测点工作电压及不同测试频率下的电路增益,各用一个独立的神经网络依据改进的BP算法对电路实施初级诊断;然后根据初级诊断结果,运用模糊融合诊断方法进行故障定位.所提方法能充分利用故障信息,对模拟电路的软故障与多故障均可进行诊断,故障定位准确率高.     

A new approach for automatic fault diagnosis in analogue circuits

In this paper the problem of fault diagnosis in analogue circuits is addressed by a method which can be regarded as an artificial intelligence approach. the topology of the circuit under test along with the nominal element values, the necessary element models and their possible failure modes are the basic tools used in the procedure. Fault location is accomplished using appropriate DC node voltage measurements under certain DC excitations on the nominal circuit and the faulty one. the detection of signal faults which have DC effects is the goal of the method; cases of faults with non-DC effects are also examined. Demonstrative examples are given to show the applicability of the method on passive and active analogue circuits.     

A method of analogue-digital multiple fault diagnosis

This paper develops an algorithm for multiple fault diagnosis of analogue-digital circuits. By sequentially partitioning the devices into those ‘assumed good’ and those ‘under test’, it is possible to develop a set of fault diagnosis equations which account for the special nature of digital components. A modified Newton-Raphson solution is then described which incorporates a digital state hypothesis testing scheme in the solution of the fault diagnosis equations for each partition. After solving for the input-output characteristics of the devices under test, a Boolean decision algorithm is used to analyse the test results of each partition and thus sequentially arrive at the set of faulty elements. A generic condition for diagnosability in terms of the circuit topology is given. Two examples are included to illustrate the technique.     

基于改进D-S证据理论的智能站保护二次回路故障诊断方法

当智能站继电保护二次回路存在故障时,故障元件难以快速、有效地被识别。为此,提出一种智能站保护二次回路故障诊断方法。首先,根据SCD文件建立二次回路的物理回路和虚回路模型,确立它们的映射关系。其次,利用举证表法获得故障二次回路的可疑故障元件集合。然后,利用改进D-S证据理论对可疑故障元件集合中的元件进行评估,获得各元件导致回路故障的概率,实现故障元件定位。最后,算例分析表明该方法能够解决元件自检告警证据冲突过大的问题,准确识别故障元件,对继电保护运维工作具有参考价值。     

单相级联中点箝位整流器IGBT和传感器的统一故障诊断方法

电力电子牵引变压器(PETT)含有大量易故障的绝缘栅双极型晶体管(IGBT)以及传感器,导致系统可靠性和稳定性降低.以PETT前端的输入级——单相级联中点箝位整流器(SPCNPCR)为对象,研究了一种IGBT与传感器故障的统一故障诊断方法.首先,建立SPCNPCR的混合逻辑动态模型,并通过此模型估计得到网侧输入电流和输...