基于复模型的模拟电路故障诊断

参数故障诊断和容差问题是模拟电路故障诊断的两个主要难题。该文从故障建模入手，提出一种新的复数域参数故障统一建模方法。模拟电路输出电压的实部和虚部都是故障元件参数的函数，联立实部和虚部函数，并消掉被建模元件参数，得到与参数无关的函数。该函数只由电路结构、故障元件位置和无故障元件的参数确定。因此，以它作为故障模型就与参数无关，能描述任何参数漂移、开路和短路故障。该模型函数是二次函数，除了无故障点之外，不同元件的模型函数会在复平面上相交于第二个点，称为混叠问题。该文采用多频方法来消除此混叠现象。仿真结果验证了方法的有效性。

Complex Fault Modeling Based Analog-Circuit Fault Diagnosis

Parameter fault and tolerance are two challenging problems in analog circuit fault diagnosis. This paper proposes approaches to solve such problems. First, a new fault modeling method and its theoretical proof are presented. In analog circuits, both the real part and the imaginary part of output voltage are the functions of fault component parameters. By eliminating component parameters from the simultaneous formulas, a new equation is achieved. It is independent from the value of component parameters and uniquely determined by the component locations and the topological structure. Hence, the function can be used as the fault model, which is applicable to both hard (open or short) and soft (parametric) faults. It is also applicable to either linear or nonlinear analog circuits. Then, the parameter tolerance is taken into consideration. A frequency selection method is proposed to maximize the difference between fault signatures. Hence, the aliasing problem arise from tolerance can be mitigated. The effectiveness of the proposed approaches is verified by simulated results.