Static compression test on the Honeycomb sandwich structure with surface core defect carry out in this paper. The specimen divided into four groups, one had no defect, one had circle defect, the other two groups had r...Static compression test on the Honeycomb sandwich structure with surface core defect carry out in this paper. The specimen divided into four groups, one had no defect, one had circle defect, the other two groups had rectangular defect in different direction. In the process of loading the strain gauge which located on the specimen surface in each group record the strain transformation of the specimen surface. Through the Static load test on the fatigue testing machine, fracture load of each specimen was record. According to the data, how the size and shape of the defect influence the compression static strength of Honeycomb sandwich was discussed, and inspecting defects direction how to affect the structural static slrength by means of theoretical analysis and data fitting, meanwhile the shape of the defects in structure how to effect buckling was discussed too.展开更多
直流微电网中Buck变换器常被用于变换高压母线直流电压,其中电解电容是最易失效的元件。电容退化参数分析表明,等效串联电阻ESR(equivalent series resistance)是电解电容的最佳健康指标,因此在线实时监测ESR的变化十分关键。针对Buck...直流微电网中Buck变换器常被用于变换高压母线直流电压,其中电解电容是最易失效的元件。电容退化参数分析表明,等效串联电阻ESR(equivalent series resistance)是电解电容的最佳健康指标,因此在线实时监测ESR的变化十分关键。针对Buck变换器提出1种基于输出电压的非侵入式在线监测输出电容ESR的方法。该方法利用驱动信号拟合出电感电流交流分量,并结合输出电压交流分量建立ESR的实时在线计算模型。该方案无需额外的电流传感器和高精度的触发采样装置,只需采样输出电压,结合开关管驱动信号,就可实现不同工作状态下Buck电路输出电容ESR的精确计算。最后,搭建了1台ESR监测系统实验平台并进行了实验验证,实验结果证明了所提方法的有效性。展开更多
A multi-phase stacked interleaved buck converter(SIBC)is suitable for large-power water electrolysis applications due to its merits of high current output capability and zero output current ripple.However,the auxiliar...A multi-phase stacked interleaved buck converter(SIBC)is suitable for large-power water electrolysis applications due to its merits of high current output capability and zero output current ripple.However,the auxiliary converter used to compensate for the current ripple still has to withstand high voltage stress.This paper proposes a new multi-phase SIBC applied in the multicarrier energy system integrating electricity,heat,and hydrogen.A resistor-capacitor voltage divider is used to provide the input voltage of the auxiliary converter and as a heater for the thermal loads.Thus,the voltage stress of the auxiliary converter can be reduced at a low cost,and the size of the filter inductor can be reduced.With accurate voltage and current analysis and appropriate parameter design,the voltage stresses of both the switches and capacitors in the auxiliary converter can be further limited within an expected range.The experimental results verify the correctness of the topology,modulation,analysis,and design methods.A comparison with the conventional method is made in terms of cost,volume,and efficiency to show the advantages of the proposed method.展开更多
文摘Static compression test on the Honeycomb sandwich structure with surface core defect carry out in this paper. The specimen divided into four groups, one had no defect, one had circle defect, the other two groups had rectangular defect in different direction. In the process of loading the strain gauge which located on the specimen surface in each group record the strain transformation of the specimen surface. Through the Static load test on the fatigue testing machine, fracture load of each specimen was record. According to the data, how the size and shape of the defect influence the compression static strength of Honeycomb sandwich was discussed, and inspecting defects direction how to affect the structural static slrength by means of theoretical analysis and data fitting, meanwhile the shape of the defects in structure how to effect buckling was discussed too.
文摘直流微电网中Buck变换器常被用于变换高压母线直流电压,其中电解电容是最易失效的元件。电容退化参数分析表明,等效串联电阻ESR(equivalent series resistance)是电解电容的最佳健康指标,因此在线实时监测ESR的变化十分关键。针对Buck变换器提出1种基于输出电压的非侵入式在线监测输出电容ESR的方法。该方法利用驱动信号拟合出电感电流交流分量,并结合输出电压交流分量建立ESR的实时在线计算模型。该方案无需额外的电流传感器和高精度的触发采样装置,只需采样输出电压,结合开关管驱动信号,就可实现不同工作状态下Buck电路输出电容ESR的精确计算。最后,搭建了1台ESR监测系统实验平台并进行了实验验证,实验结果证明了所提方法的有效性。
基金supported in part by the National Natural Science Foundation of China(52077190)Cultivation Project for Basic Research and Innovation of Yanshan University(2021LGQN007)Science and Technology Project of Hebei Education Department(QN2024202).
文摘A multi-phase stacked interleaved buck converter(SIBC)is suitable for large-power water electrolysis applications due to its merits of high current output capability and zero output current ripple.However,the auxiliary converter used to compensate for the current ripple still has to withstand high voltage stress.This paper proposes a new multi-phase SIBC applied in the multicarrier energy system integrating electricity,heat,and hydrogen.A resistor-capacitor voltage divider is used to provide the input voltage of the auxiliary converter and as a heater for the thermal loads.Thus,the voltage stress of the auxiliary converter can be reduced at a low cost,and the size of the filter inductor can be reduced.With accurate voltage and current analysis and appropriate parameter design,the voltage stresses of both the switches and capacitors in the auxiliary converter can be further limited within an expected range.The experimental results verify the correctness of the topology,modulation,analysis,and design methods.A comparison with the conventional method is made in terms of cost,volume,and efficiency to show the advantages of the proposed method.
