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

传统和/或新兴AC和DC电力系统中的快速故障隔离（RFI）从可靠性、稳定性、电能质量和容量利用率的观点来看已经成为极其重要的问题。该项目旨在开发一种基于碳化硅的光激活门极可关断晶闸管（SiC OA-GTO），该晶闸管有望成为RFI领域的游戏规则改变者，并基于全新的创新技术带来明显的器件和系统级优势。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，转换开关，中压驱动器的高压电力电子转换器，储能，太阳能和风能的升压变压器集成以及灵活的交流输电系统（FACTS），仅举几例。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，包括少数民族和跨学科学生的重要代表。每年夏天将向一名中学生提供指导。研究结果将被纳入课程ECE 442（功率半导体器件和集成电路）。该项目的技术目标如下：1）合成高增益单片SiC基光激活（OA）门极可关断晶闸管（即，SiC OA-GTO）用于实现快速故障隔离器件（RFID）（即，SiC OA-RFID）。 预期SiC OA-RFID支持高击穿电压、高额定电流和浪涌电流、高转换速率、低导通状态正向压降、高结温以及使用低平均光触发功率的操作; 2）设计用于SiC OA-GTO的最佳光子封装，然后使用它实现SiC OA-RFID以解决在存在大di/dt、热鲁棒性的情况下减小的寄生电感，以及通过最佳射束定位来均匀且有效地触发和减轻电流抑制;以及3）在封装级对所制造的原型器件进行实验I-V和开关表征以用于性能验证。用于OA-RFID的SiC OA-GTO器件结合了几个关键特征：a）单片SiC器件结构，其减轻了产生高di/dt的寄生电感; B）由于新颖的光激励和单位增益关断而导致的快速导通和关断; c）由于晶闸管动作和电导率调制而导致的非常低的光功率要求; d）低正向压降; e）无缝电压和电流缩放; f）高电压阻断和电流传导; g）高热导率; h）简化切换的新颖光学触发;以及i）不依赖于氧化物层。新的光学单偏置设备，不像领先的高电压硅和碳化硅为基础的设备产生抗噪声，增强的可靠性，并减少由于直接光生延迟。此外，光学触发消除了与负栅极参考相关联的复杂性。该光学器件增强了SiC OA-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SiC OA-GTO的器件动态，从而产生减小的延迟和改进的导通状态和关断状态特性。

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.