Research On Intermittent Fault Diagnosis For Electronic Circuit

With the great improvement of Electronic Engineering Technology in lots of fields,circuit plays a vital role in electronic equipment.With the improvement of fault detection and diagnosis technology,a special kind of fault,intermittent fault,occurs in the operation of the system.It has a short duration and is easy to be hidden,so it is a potential hazard source in the electronic circuit system.Intermittent fault is a temporary failure caused by instantaneous external factors and internal degradation of components.It may occur under the trigger of external conditions and recover in a limited time without treatment.Its characteristics are strong randomness,short duration and changeable characteristics.There are many kinds of components in electronic circuits,and their failure modes are different.Moreover,the structure and functions of electronic systems are more complex,which makes it difficult to acquire and transmit signals,process signals and extract features,diagnose and make decisions when electronic circuits occur intermittent faults,so it is easy to cause false alarm.At present,the difficulties in the study of intermittent faults in electronic circuits mainly focus on the lack of mechanism model,deterministic detection of intermittent faults,location of intermittent faults and the lack of diagnostic methods for the characteristics of intermittent faults.In view of these difficulties and the existing problems in the research,this paper mainly includes the following contents.In view of the fact that the mechanism of circuit intermittent fault is not very clear at present,the mechanism and law of intermittent fault induced by environmental stress and degradation of circuit components are analyzed in combination with the characteristics and evolution law of intermittent fault.Then establishing the singularity signal model of intermittent faults.The singularity signal is used to represent the intermittent faults such as uncertain fluctuation of the system,and the detection of intermittent faults is converted to the detection of singularity signals.Finally,the detection of intermittent faults in circuits is realized by the detection method of wavelet transform modulus maxima.Considering the characteristics of dynamic non-stationarity,strong randomness,singularity and sparsity of intermittent faults,combined with the characteristics of singularity signals in intermittent faults,the refined invariant features of signals are extracted by LMD multi-scale entropy.The method based on DHMM can deal with the transition relationship between states in time series and identify dynamic non-stationary signals.At the same time,due to the singularity and sparsity of intermittent faults.The diagnosis based on SRC can effectively reconstruct the intermittent fault signal by learning the decomposition coefficients of dictionary.Therefore,combining the advantages of the two methods,a method of circuit intermittent fault diagnosis based on DHMM-SRC joint decision-making is proposed,and the effectiveness of the method is verified by experiments.Aiming at the problem that it is difficult to locate intermittent faults in circuits,this paper collects the data of various states of different fault points and identifies which fault point produces intermittent faults by diagnostic algorithm,thus realizing the line location of intermittent faults in circuits.Finally,taking the circuit of FOUR-OPAMP band-pass filter as the object,the proposed method can be validated effectively by building a circuit intermittent fault diagnosis platform,from circuit construction,intermittent fault simulation,data acquisition to algorithm verification.Compared with other algorithms,the results show that the proposed algorithm for batch fault diagnosis of electronic circuits is effective.