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Condition monitoring of inverter power devices based on electromagnetic acoustic emissions
Fei Liu,Chenghao Zeng,Liang Cheng,Yunze He,Yun Bai,Xuefeng Geng,Songyuan Liu,Dantong Ren,Lei Wang 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.12
Unlike conventional voltage and current sensing, this paper studies the use of acoustic emission signals to detect the condition of the power device for a DC–AC inverter. As a relatively new method for monitoring power devices, there are some unknown phenomena in acoustic emissions (also called mechanical stress wave). Therefore, the authors present an experimental setup that is used to analyze acoustic emission signals. Based on experimental results, some interesting points have been found: (1) The generation of a mechanical stress wave is verified for the first time. (2) The time-domain peak value, energy, and rise time of the mechanical stress wave at the turn-on time of a power device are barely affected by the load. Meanwhile, these values decrease with an increase of the load at the turn-off time. (3) The frequency-domain peak value of the mechanical stress wave tends to decrease with an increase of the load, and the peak frequency is barely affected by the load. These mechanical stress analysis results can be utilized for condition monitoring in many applications.
Yan, Changzeng,Xue, Xiaolan,Zhang, Wenjun,Li, Xiaojie,Liu, Juan,Yang, Songyuan,Hu, Yi,Chen, Renpeng,Yan, Yaping,Zhu, Guoyin,Kang, Zhenhui,Kang, Dae Joon,Liu, Jie,Jin, Zhong unknown 2017 Nano energy Vol.39 No.-
<P><B>Abstract</B></P> <P>To produce hydrogen and oxygen from photocatalytic overall splitting of pure water provides a promising green route to directly convert solar energy to clean fuel. However, the design and fabrication of high-efficiency photocatalyst is challenging. Here we present that by connecting different nanostructures together in a rational fashion, components that cannot individually split water into H<SUB>2</SUB> and O<SUB>2</SUB> can work together as efficient photocatalyst with high solar-to-hydrogen (STH) energy conversion efficiency and avoid the use of any sacrificial reagent. Specifically, Te/SnS<SUB>2</SUB>/Ag artificial nanoleaves (ANLs) consist of ultrathin SnS<SUB>2</SUB> nanoplates grown on Te nanowires and decorated with numerous Ag nanoparticles. The appropriate band structure of Te/SnS<SUB>2</SUB> p-n junctions and the surface plasmon resonance of Ag nanoparticles synergistically enhance the quantum yield and separation efficiency of electron-hole pairs. As a result, Te/SnS<SUB>2</SUB>/Ag ANLs enable visible-light driven overall water-splitting without any sacrificial reagent and exhibit high H<SUB>2</SUB> and O<SUB>2</SUB> production rates of 332.4 and 166.2μmolh<SUP>−1</SUP>, respectively. Well-preserved structure after long-term measurement indicates its high stability. It represents a feasible approach for direct H<SUB>2</SUB> production from only sunlight, pure water, and rationally-designed ANL photocatalysts.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Te/SnS<SUB>2</SUB>/Ag ANLs heterostructure is prepared to catalyze overall water splitting. </LI> <LI> The catalyst show impressive H<SUB>2</SUB> and O<SUB>2</SUB> production rate under visible light. </LI> <LI> The structure and efficiency of catalyst shows no degradation after 10 days. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>