High-Voltage Optically-Activated Wide-Bandgap Rapid Fault Isolation Device

从可靠性、稳定性、电能质量和容量利用率的角度来看，传统和/或新兴交直流电力系统中的快速故障隔离(RFI)已经成为一个极其重要的问题。该项目旨在开发一种基于碳化硅的光学激活门极关断晶闸管(SiCOA-GTO)，有望改变RFI的游戏规则，基于全新的创新，具有明显的设备和系统级优势。SIC OA-GTO还将为几个主要应用带来明显的好处，包括脉冲功率系统、传输开关、用于中压驱动的高压电力电子转换器、能量存储、太阳能和风能的无升压变压器集成以及灵活的交流输电系统(FACTS)等等。这个国家科学基金会(NSF)项目将提供研究生和本科生水平的研究和教育机会，包括少数族裔和跨学科学生的重要代表。每年暑假将向一名中学生提供指导。这项研究的成果将被纳入欧洲经委会442课程(电力半导体器件和集成电路)。该项目的技术目标如下：1)合成一种用于实现快速故障隔离装置(即，SiCOA-RFID)的高增益单片单片光学激活(OA)门控晶闸管(即，SiCOA-GTO)。预计SiCOA-RFID将支持高击穿电压、高额定电流和浪涌电流、高转换速率、低导通正向降、高结温，以及使用低平均光触发功率进行操作；2)为SiCOA-GTO设计最佳光子封装，然后使用它实现SiCOA-RFID，以解决寄生电感降低的问题，因为它存在大的di/dt、热稳健性，并且通过最佳束流局部化来均匀有效地触发和缓解电流丝化；以及3)为了性能验证，在封装水平上对所制作的原型器件进行了实验I-V和开关表征。用于OA-RFID的SiCOA-GTO器件具有几个关键特征：a)单片SiC器件结构，其减少了产生高di/dt的寄生电感；b)由于新颖的光激励和单位增益关断而快速开启和关闭；c)由于晶闸管动作和电导率调制而非常低的光功率需求；d)低正向降；e)无缝电压和电流调节；f)高电压阻断和电流传导；g)高导热性；h)简化开关的新颖光触发；以及i)不依赖氧化层。与领先的高压硅和碳化硅器件不同，新的光学单偏置器件具有抗噪声能力、增强的可靠性和由于直接光生而减少的延迟。此外，光学触发消除了与负栅极参考相关的复杂性。该光学器件增强了SiCOA-GTO功率级和低压控制级之间的隔离。器件的光子调制使得能够动态控制SiCOA-GTO的器件动态，从而减少了延迟并改善了通态和关态特性。

Rapid Fault Isolation (RFI) in legacy and/or emerging AC and DC power systems has emerged as an extremely important issue from the reliability, stability, power quality, and capacity utilization viewpoints. This project seeks to develop a silicon-carbide based optically-activated gate-turn-off thyristor (SiC OA-GTO) that is expected to be a game changer in RFI, with clear device and system level benefits based on radically new innovations. The SiC OA-GTO will also have clear benefits for several major applications including pulsed-power systems, transfer switches, high-voltage power electronic converters for medium-voltage drives, energy storage, step-up-transformerless integration of solar and wind energy, and flexible AC transmission systems (FACTS), to name a few. This National Science Foundation (NSF) project will provide graduate- and undergraduate-level research and education opportunities, including a significant representation of minority and cross-disciplinary students. Guidance will be provided to one middle-school student each summer. The results of the research will be integrated into the course ECE 442 (Power semiconductor devices and integrated circuits). The PI will leverage his demonstrated mechanisms of research dissemination (for his ongoing and prior NSF projects) to support this NSF project.The technical objectives of this project are as follows: 1) To synthesize a high-gain monolithic SiC based optically-activated (OA) gate-turn-off thyristor (i.e., SiC OA-GTO) for realization of a Rapid Fault Isolation Device (RFID) (i.e., SiC OA-RFID). The SiC OA-RFID is expected to support high breakdown voltage, high rated and surge currents, high slew rate, low on-state forward drop, high junction temperature, and operation using low average optical triggering power; 2) To design an optimal photonic package for the SiC OA-GTO and then using it realize a SiC OA-RFID to address reduced parasitic inductance given the presence of large di/dt, thermal robustness, and uniform and efficient triggering and mitigation of current filamentation by optimal beam localization; and 3) Experimental I-V and switching characterizations of the fabricated prototype device at package levels for performance validations. The SiC OA-GTO device for the OA-RFID incorporates several key features: a) a monolithic SiC device structure that mitigates parasitic inductances yielding high di/dt; b) rapid turn-on and turn-off due to novel optical excitation and unity-gain turn off; c) very low optical power requirement due to thyristor action and conductivity modulation; d) low forward drop; e) seamless voltage and current scaling; f) high-voltage blocking and current conduction; g) high thermal conductivity; h) novel optical triggering that simplifies switching; and i) no dependence on oxide layer. The new optical single-bias device, unlike leading high voltage Si and SiC based devices yields immunity against noise, enhanced reliability, and reduced delay due to direct photogeneration. Additionally, optical triggering eliminates complexity associated with negative gate referencing. The optical device enhances isolation between the SiC OA-GTO power stage and the low-voltage control stage. Photonic modulation of the device enables dynamic control of device dynamics of the SiC OA-GTO yielding reduced delay and improved on-state and off-state characteristics.