Reliability Assessment Of Power Conditioning System In High Pulsed Power Supply

Inertial confinement fusion laser diver is used to start the thermonucleal fusion reaction under laboratory conditions using high power laser.The construction of laser driver facility represents scientific research,power sector and national defense industry construction.The SG-? inertial confinement fusion laser driver facility is a significant national science project.As an important part of the laser device,the reliability of power conditioning system is directly related to the main technical indicators,the reliability and the system shot success ratio of the laser driver facility.Therefore,in engineering practice,it is essencial to conduct reliability analysis for the power conditioning system.Most reported reliability assessment work for complex system are based a premise that the failure rate of component is constant and the failure processes of components are independent.The power conditioning system has complex and precise structure,various fault modes,unstable and rigorous working conditions,and a large number of redundant designs,the failure processes of component are dependent,possess time-varying failure mechanism and multiple failure modes.This dissertation devotes to implement Fault Modes Effect and Criticality Analysis and Fault Tree Analysis for system,conduct reliability modeling of multi-component systems with common cause failure and dynamic working environment,assess the reliability and opitimize the structure of load sharing multi-component system.The primary research contributions and innovative outcomes are summarized as follows:Fault Modes Effect and Criticality Analysis and Fault Tree Analysis for power conditioning system.Firstly,the system structure and function is analyzed deeply,and the FMECA method is adopted to identify the fault modes of each component and its influence on the system,finds out the weakness and critical components of system.Secondly,based on the analysis results,the FTA is conducted for the critical subsystems.The results show that the thyristor switch in the main discharge switch subsystem and the capacitor in the capacitor energy storage subsystem possess the highest criticality,are the most important components,which need to be analyzed detailedly.Reliability evaluation of system with common cause failure by using dynamic Bayesian networks.By taking into account of the dependent failure processes among components caused by the same environment and/or redundant design,a reliability evaluation model for system with common cause failure is put forth.The proportional hazard model is used to capture the effects of dynamic working environment on components' failure mechanism.The dynamic Bayesian networks model is employed to model the common cause failure phenomena and estimate the system reliability.As demonstrated by a set of numerical examples,the reliability would be overestimated when the working environment is ignored,meanwhile,the reliability would be underestimated while the failure processes are modeled independently.Reliability assessment and optimization for load-sharing multi-component systems.The proposed inference method generally consists of three steps.Firstly,the inherent relation between component's transition intensity and suffered loads is characterized by a Proportional Hazard model,and the failure process of the system is modeled by a Markov model.Secondly,the Phase-Type distribution and aggregated Markov model are employed to compute the analytical solution of reliability function.Thirdly,a reliability optimization model for load-sharing system is proposed,a single-objective and a multi-objective optimization problems are formulated,the Particle Swarm Optimization algorithm is used to obtain the optimal solution of system structure and components' state transient intensity.Compared with the solution obtained from Monte Carlo simulation,the proposed model can estimate reliability efficiency and accurately.