Time-Varying Threshold and Signed-Rectified Regressor Design of Diagnosis Observer for Analog Circuits With Intermittent Fault

Abstract

Swift and accurate fault diagnosis plays a critical role in analog circuit systems for subsequent disposing and avoiding catastrophic evolution. This work presents a novel time-varying threshold (TvT) design to generate swift detection regarding to both fault alarming and relieving against intermittent faults with elaborated principles of choosing proper parameters, including threshold infimum, metastable threshold, decaying coefficient, and time-domain repartition techniques. Followed by swift detection, a new signed-rectified alarming moment-triggered identification algorithm is proposed to provide an unbiased estimation of unknown faults, holding an essentially persistent excitation (PE) property. Detectability regarding to intermittent fault’s occurrence and relievement is given with analysis in depth. A simulation example with comparisons is given to demonstrate the effectiveness and merits of the proposed algorithms.