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DC fault is one of the most important and critical challenges for stable operation of DC microgrids. Resistive type superconducting fault current limiter (R-SFCL) is an ideal protective solution to limit DC fault current. However, the effect of only using SFCL may further deteriorate the DC bus voltage stability. This paper first analyzes the effect of R-SFCL on DC microgrid under different operation modes and different fault locations, and then presents a coordinated control method of SMES-battery hybrid energy storage system (HESS) and SFCL in ground fault. This method can not only reduce the fault current level but also regulate the DC bus voltage. Finally, the comparative study is conducted in PSCAD/EMTDC, the feasibility and superiority of the proposed method is verified. [ABSTRACT FROM AUTHOR]

In this letter, we report an in-situ pre-deposition plasma nitridation process, which is adopted to remove the GaN surface oxygen-related bonds and reduce surface dangling bonds by forming Ga-N bonds prior to the low-pressure chemical vapor deposition (LPCVD)-Si3N4 deposition. It demonstrates that the V \sf {th} hysteresis and current collapse of the device were dramatically improved due to high-quality LPCVD-Si3N4/GaN interface. The MIS-HEMTs using this in-situ pre-deposition plasma nitridation exhibit a very-low V \sf {th} hysteresis of 186 mV at V \text {G-sweep} = (−30 V, +24 V), a high breakdown voltage of 881 V with the substrate grounded. Meanwhile, the MIS-HEMT dynamic R \mathrm{ ON} is only 18% larger than the static R \mathrm{ ON} after OFF-state V \sf {DS} stress of 600 V (the OFF to ON switching time interval is set to 200~\mu \texts ). [ABSTRACT FROM PUBLISHER]

In this paper, we systematically investigated the leakage and breakdown mechanisms of the low-pressure chemical vapor deposition (LPCVD) silicon nitride thin film deposited on AlGaN/GaN heterostructures. The LPCVD-SiNx gate dielectric exhibits low leakage and high breakdown electric field. The dominant mechanism of the leakage current through LPCVD-SiNx gate dielectric is identified to be Poole–Frenkel emission at low electric field and Fowler–Nordheim tunneling at high electric field. Both electric-field-accelerated and temperature-accelerated time-dependent dielectric breakdown of the LPCVD-SiNx gate dielectric were also investigated. [ABSTRACT FROM PUBLISHER]

We present a design study of the Deep Insights Anywhere, Anytime (DIA2) platform, a web-based visual analytics system that allows program managers and academic staff at the U.S. National Science Foundation to search, view, and analyze their research funding portfolio. The goal of this system is to facilitate users' understanding of both past and currently active research awards in order to make more informed decisions of their future funding. This user group is characterized by high domain expertise yet not necessarily high literacy in visualization and visual analytics-they are essentially casual experts-and thus require careful visual and information design, including adhering to user experience standards, providing a self-instructive interface, and progressively refining visualizations to minimize complexity. We discuss the challenges of designing a system for casual experts and highlight how we addressed this issue by modeling the organizational structure and workflows of the NSF within our system. We discuss each stage of the design process, starting with formative interviews, prototypes, and finally live deployments and evaluation with stakeholders. [ABSTRACT FROM PUBLISHER]

In this letter, silicon nitride (SiNx) film deposited at 780 °C by low-pressure chemical vapor deposition (LPCVD) was employed as gate dielectric for GaN-based metal–insulator–semiconductor high-electron-mobility transistors. The LPCVD-SiNx exhibit improved gate dielectric performance than the plasma enhanced chemical vapor deposition-SiNx, including smaller forward and reverse gate leakage, and higher forward gate breakdown voltage. [ABSTRACT FROM AUTHOR]

A novel double-gate AlGaN/GaN HEMT, in which an additional top-gate covers the adjacent regions of a normal gate, was proposed and fabricated for the first time to compare the dynamic characteristics of AlGaN/GaN HEMTs with a source field plate (SFP) and a gate field plate (GFP). During the dynamic characterization, the device was configured in two operation modes: One is the SFP mode with the top gate biased at 0 V, and the other is the GFP mode applying the gate pulse signal on the top gate at the same time. Compared with an AlGaN/GaN HEMT without field plates, both GFP and SFP much improve the dynamic performances. Compared with the SFP, the GFP shows better dynamic performances with a \sim34% reduction of switch-on delay time and \sim6% reduction of dynamic on-state resistance. Studying the dynamic characteristics and applying negative voltage on the top gate during the off state, the mechanism differences between the GFP and the SFP are discussed in detail. [ABSTRACT FROM AUTHOR]