In this paper,a fault-tolerance wide voltage conversion gain DC/DC converter for More Electric Aircraft(MEA)is proposed.The proposed converter consists of a basic Cuk converter module and n expandable units.By adjusti...In this paper,a fault-tolerance wide voltage conversion gain DC/DC converter for More Electric Aircraft(MEA)is proposed.The proposed converter consists of a basic Cuk converter module and n expandable units.By adjusting the operation state of the expandable units,the voltage conversion gain of the proposed converter could be regulated,which makes it available for wide voltage conversion applications.Especially,since mutual redundancy can be realized between the basic Cuk converter module and the expandable units,the converter can continuously work when an unpredictable fault occurs to the fault-tolerant parts of the proposed converter,which reflects the fault tolerance of the converter and significantly improves the reliability of the system.Moreover,the advantages of small input current ripple,automatic current sharing and low voltage stress are also integrated in this converter.The working principle and features of the proposed converter are mainly introduced,and an experimental prototype with 800 W output power has been manufactured to verify the practicability and availability of the proposed converter.展开更多
Objective:To report a numerical research on the effect of a renal artery arising from false lumen(FL)on the treatment outcome of thoracic endovascular repair(TEVAR)for complicated type B aortic dissection(TBAD).Method...Objective:To report a numerical research on the effect of a renal artery arising from false lumen(FL)on the treatment outcome of thoracic endovascular repair(TEVAR)for complicated type B aortic dissection(TBAD).Methods:The original patient-specific model with the right renal artery(RRA)partially supplied by the FL(TFM)was reconstructed from its postoperative computed tomography images.Two additional models were reconstructed by artificially modifying the RRA either fully arising from the FL(CFM)or true lumen(CTM).Computational fluid dynamics(CFD)simulations were performed.Results:First,for all the models,the flow splits to all the visceral arteries were much less than those of a healthy aorta.Second,the flow split to RRA in the CFM and in CTM was the least and largest respectively.Third,in TFM,the pressure gradient between the true lumen(TL)and FL was negative at the proximal FL and the entire FL was full of active blood flow.In the contrast,in CTM and CFM,the pressure differences between the two lumens remained positive and little flow was present in FL.Finally,both TL and proximal FL of this particular patient expanded and the diameters of all visceral arteries decreased at one-year follow-up.Conclusions:Compared to a healthy aorta,a renal artery arising from FL following TEVAR would result in severe visceral ischemia including RA and superior mesenteric artery(SMA).In addition,our numerical simulation of the postoperative hemodynamics of this particular patient perfectly matched with its TL remodeling,FL expansion and contraction of the visceral arteries at one-year follow-up,and a patient-specific CFD simulation may be adopted to obtain information on visceral perfusion after endovascular repair for TBAD patients.展开更多
基金supported by the National Natural Science Foundation of China(No.51707103)the Hubei Provincial Key Laboratory on Operation and Control of Cascaded Hydropower Station,China(No.2022KJX08).
文摘In this paper,a fault-tolerance wide voltage conversion gain DC/DC converter for More Electric Aircraft(MEA)is proposed.The proposed converter consists of a basic Cuk converter module and n expandable units.By adjusting the operation state of the expandable units,the voltage conversion gain of the proposed converter could be regulated,which makes it available for wide voltage conversion applications.Especially,since mutual redundancy can be realized between the basic Cuk converter module and the expandable units,the converter can continuously work when an unpredictable fault occurs to the fault-tolerant parts of the proposed converter,which reflects the fault tolerance of the converter and significantly improves the reliability of the system.Moreover,the advantages of small input current ripple,automatic current sharing and low voltage stress are also integrated in this converter.The working principle and features of the proposed converter are mainly introduced,and an experimental prototype with 800 W output power has been manufactured to verify the practicability and availability of the proposed converter.
基金This work was supported by grants from National Natural Science Foundation of China(81770471,12072214,1802253)Sichuan Provincial Department of Science and Technology Application Basic Project(2018YYJC,2019YJ0026).
文摘Objective:To report a numerical research on the effect of a renal artery arising from false lumen(FL)on the treatment outcome of thoracic endovascular repair(TEVAR)for complicated type B aortic dissection(TBAD).Methods:The original patient-specific model with the right renal artery(RRA)partially supplied by the FL(TFM)was reconstructed from its postoperative computed tomography images.Two additional models were reconstructed by artificially modifying the RRA either fully arising from the FL(CFM)or true lumen(CTM).Computational fluid dynamics(CFD)simulations were performed.Results:First,for all the models,the flow splits to all the visceral arteries were much less than those of a healthy aorta.Second,the flow split to RRA in the CFM and in CTM was the least and largest respectively.Third,in TFM,the pressure gradient between the true lumen(TL)and FL was negative at the proximal FL and the entire FL was full of active blood flow.In the contrast,in CTM and CFM,the pressure differences between the two lumens remained positive and little flow was present in FL.Finally,both TL and proximal FL of this particular patient expanded and the diameters of all visceral arteries decreased at one-year follow-up.Conclusions:Compared to a healthy aorta,a renal artery arising from FL following TEVAR would result in severe visceral ischemia including RA and superior mesenteric artery(SMA).In addition,our numerical simulation of the postoperative hemodynamics of this particular patient perfectly matched with its TL remodeling,FL expansion and contraction of the visceral arteries at one-year follow-up,and a patient-specific CFD simulation may be adopted to obtain information on visceral perfusion after endovascular repair for TBAD patients.
