Research On Fault Diagnose And Toelerant Control Strategy Of Aviation VIENNA Rectifier

With the development of more-electric and all-electric aircraft,the requirements of aviation power supply systems are becoming higher and higher.In the aviation power supply system,rectifier plays the role of converting AC into DC power,whose performance will influence the secondary power supply system.The Vienna rectifier has been widely used for high efficiency,low THD and low voltage stress.In order to meet the requirements for high reliability,high power density,low failure rate and low fuel consumption,it is necessary to improve the reliability and power density of Vienna rectifier.For the requirement of high reliability,this paper analyzes the effects of small,medium and large vectors on the DC bus voltage based on SVPWM method.The principle of vector synthesis of the SVPWM and the duty of each switch are described.Combined with the simulation analysis,the current characteristics of the Vienna rectifier under open-circuit fault of the switches are obtained.Based on the characteristics under open-circuit fault,a fault diagnose method which dectects the current slew rate at specified angle is proposed.Additionally,a fault-tolerant control method is proposed based on the fault type,that is: redundant small vectors are used to replace the corresponding vector to maintain threelevel operation in area where just small vectors are ineffective,uncontrolled rectifier is used to replace three-level control where medium vectors are ineffective.Considering the effect of small vectors,the areas for the balance of DC bus voltage are added.Finally,the simulation and experimental results verify the effectiveness and feasibility of proposed method.In order to meet the requirement of high power density,the switches of Vienna rectifier are selected for 115V/400 Hz applications.GaN HEMTs from three different companies are analyzed based on power loss,driving characteristics,safe operation space and price for better performance of the rectifier.Based on the analysis above,the advice for selction under different applications can be achieved.Finally,the simulation and experimental results verify the selection method.