Research On Testability Design Of Switching Mode Power Supply Considering Conducting Electromagnetic Interference

Switching mode power supply is an important energy conversion equipment in electronic system.Its reliable operation can ensure the stable work of the electronic system.When the power supply fails,good testability design can realize the rapid detection and isolation of the fault,which can effectively improve the reliability of the power supply.Therefore,it is of great significance to carry out testability design for switching mode power supply to ensure the safe operation of power supply and even the whole system.However,there is a lot of electromagnetic interference in the switching mode power supply.In the process of testability design,if the internal electromagnetic interference is ignored,the accuracy of testability design will be seriously affected,so that the accuracy of testability design will be seriously affected and the results of testability design will be deviated.In this paper,a DC/DC converter is taken as the research object,and its testability optimization design is carried out considering the influence of its internal conducting electromagnetic interference.Firstly,the working principle of the power supply is analyzed,the SABER simulation model is established,and the sensitivity is analyzed;According to the sensitivity analysis results and the failure rate of components,the key components of the power supply are obtained,and the main fault modes of the power supply are determined;The traditional multi-signal flow diagram modeling method is combined with fault injection simulation to model the testability of the power supply under the assumption of perfect test conditions: the power supply structure is divided according to the function,the key basic unit modules are determined,and the primary test nodes are selected.Based on Saber Monte Carlo analysis,the fault injection simulation of power supply was carried out,the test parameters of each primary test node were extracted,and the test parameter set affected by each fault mode was summarized.The fault-test correlation matrix under perfect test is constructed and its inherent testability is analyzed.Secondly,modeling and simulation of the conduction electromagnetic interference of switching mode power supply are carried out.The high frequency modeling of switching power supply is divided into two parts: one is the high frequency modeling of circuit components;The second is to extract the parasitic parameters of the power PCB board in ANSYS Q3D to construct the high-frequency model of the power supply.And the high frequency model is imported into SABER for conducting electromagnetic interference simulation.Finally,according to the simulation results of conducted EMI and testability modeling under perfect test,the fault-test correlation matrix under conducted EMI is constructed;According to the matrix,the binary particle swarm optimization algorithm was used to optimize the test,and the optimal test set conforming to the testability index was found;The optimal fault diagnosis tree was obtained by sequential diagnosis based on AO~* algorithm on the basis of optimized and screened test sets;A testability verification platform was built to verify the results of testability optimization selection.