Failure Analysis And Reliability Optimization Design Of Switching Power Supply

As the application of switching power supply is becoming more and more extensive,its reliability has also gained more and more attention.The fact that how to improve the reliability of switching power supplies as much as possible in consideration of economic costs has become a problem which companies are more concerned about.This paper took the secondary power supply of a servo motor drive system produced by an enterprise as the research object,analysed the cause of the fault,determined the fault-prone components,and simulated and reproduced the fault;built a component degradation model based on tolerance and degradation,build a fast calculation model,conducted failure rate analysis,optimized the design of the circuit,reduced the failure rate of the switching power supply,and finally formed a set of methods to reduce the failure rate of the switching power supply.First of all,the failure rate and failure mechanism of switching power supply is ana-lyzed.the failure rate is calculated,the components with high failure rate are determined,the circuit principle is analysed,the failure mechanism is determined,and the cause of the failure is determined.Based on the physical circuit,the cause of the failure is verified,and the failure analysis idea based on degradation and tolerance is determined.Based on the built simulation model which can replace the physical circuit,the fault phenomenon is reproduced,the above failure mechanism is verified,the stress of each position of the power supply is monitored,and the key nodes in the power supply is determine.Secondly,In consideration of component tolerance and degradation,the reliability of the switching power supply is analyzed.A component degradation model is built.Based on the failure rate statistical results and failure mechanism analysis obtained before,and also based on the orthogonal table,sensitivity analysis on the power supply is performed to determine the key components with high sensitivity.Based on the simulation model built above and sensitivity analysis results,through multiple simulations,the mapping re-lationship between the parameters of sensitive components and the stress of key nodes is determined,and a fast calculation model of the switching power supply is constructed.Based on the stress-strength interference model,the failure probability of each key compo-nents considering degradation and tolerance of those components is calculated.According to the failure probability of each component,the total failure rate of the system is obtained.Finally,based on the above analysis,the reliability design of the switching power supply is optimized.Based on the cost calculation formula and quality optimization crite-ria,quantify the total cost of the power supply;using this as the objective function,based on the particle swarm optimization algorithm,calculate the lowest cost,obtain the opti-mal combination of component parameters and tolerances,get the optimization results,and evaluate the optimization On this basis,the reliability of the switching power supply is optimized.