容差模拟电路参数故障诊断

Parameter fault diagnosis on analog circuits with tolerance

针对测试点有限条件下的容差模拟电路参数故障诊断问题,该文提出一种状态检测、故障隔离和状态验证及参数辨识的分步诊断策略。将容差电路的故障状态检测转化为线性规划方程最优解的存在性判断;采用Woodbury公式推导出不同电流源激励下测点处电压增量比值,将其作为故障特征,并证明容差条件下的电路故障特征值与标称参数下的仿真值是相同的;通过修正规划方程中疑似故障参数的偏差限,验证前期诊断结论的正确性并计算故障元件参数。直流、交流和非线性电路实例验证该理论的正确性和方法的有效性。该方法操作简单、可行性高,适用于大规模模拟电路的故障诊断和故障参数辨识。

Focusing on the fault diagnosis with limited test points on analog circuits withtolerance, a stepwise diagnosis strategy for fault detection, fault isolation, state verification and parameter identification is put forward. Firstly, a linear programming concept is developed to transform fault detection of circuit with limited accessible terminals for measurement to check existence of a feasible solution under tolerance constraints. The Woodbury formula is deduced under different excitation current source measuring point voltage increment ratio as the faultfeature, and prove that the simulation circuit fault tolerance characteristics under the condition of value and nominal values are the same. Lastly, fault detection of the circuit with reviseddeviation restriction for suspected faulty components is proceeded to locate faulty element andestimate its parameter. Correctness of the theory and effectiveness of the proposed method are verified by DC, AC and nonlinear circuit experimental results. The proposed method is simple and feasible and suitable for large -scale analog circuits fault diagnosis and fault parameter identification.