线性模拟电路软故障建模与诊断策略

A Novel Soft-Fault Modeling and Diagnosis Method in Linear Analog Circuit

针对线性模拟电路软故障诊断问题,提出了一种新的基于解析模型的方法。该方法利用硬故障电压值,构建电路的阻抗-电压方程,以便计算线性模拟电路软故障时系统输出电压,从而形成用于软故障诊断的故障特征向量。该文首先讨论了电路阻抗参数连续变化时,单软故障建模和模拟电路可测性分析的基本结论;其次以多故障中最常见的双故障为例,亦给出了由阻抗-电压方程确立的软故障电压建模;最后形成了相应的故障定位定值策略。在交流信号激励下的例子电路中进行建模与诊断分析,结果表明,提出的软故障建模与诊断策略运行有效,结果准确。

In order to solve the problem of soft fault diagnosis in linear analog circuit, this paper proposes a new analytic model-based method. By using hard-fault voltage value, the impedance-voltage equation is constructed for calculating the circuit output voltage when soft-fault happens and therefore forming the fault characteristic vector for soft-fault diagnosis. The single-fault modeling and testability analysis of circuits are discussed in the condition that the impedance parameter is continuously changed. Taking the most common multiple soft fault-double faults as example, the soft-fault model derived from the impedance-voltage equation is presented. At last, a strategy to determine fault location and identify fault component values is formed. The soft-fault modeling and diagnosis are demonstrated through an example circuit which is driven by an alternating signal. The result shows that the proposed soft-fault modeling and diagnosis algorithm run effectively, and can obtain the accurate fault diagnosis results.