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/或新兴交流和直流电源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激活栅关断晶闸管（SiC OA-GTO），该晶闸管有望成为RFI的游戏规则改变者，具有基于全新创新的明显设备和系统级优势。SiC OA-GTO还将在几个主要应用中具有明显的优势，包括脉冲电源系统，转换开关，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传输系统（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。每年暑假将为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）。PI将利用他所展示的研究传播机制（为他正在进行的和先前的NSF项目）来支持该NSF项目。本课题的技术目标如下：1)合成基于高增益单片SiC的光激活（OA）门关晶闸管（即SiC OA- gto），实现快速故障隔离装置（即SiC OA-RFID）。SiC OA-RFID有望支持高击穿电压、高额定和浪涌电流、高转换率、低导通状态正向降、高结温和使用低平均光触发功率的操作；2)设计了SiC OA-GTO的最佳光子封装，并利用它实现了SiC OA-RFID，以解决大di/dt，热鲁棒性和均匀有效的触发和减缓电流灯丝的最佳光束定位的存在降低寄生电感；3)封装级制造原型器件的实验I-V和开关特性，用于性能验证。用于OA-RFID的SiC OA-GTO器件包含几个关键特性：a)单片SiC器件结构，可减轻产生高di/dt的寄生电感；B)由于新型光激发和单位增益关断而快速通断；C)由于可控硅作用和电导率调制，光功率要求非常低；D)低前降；E)电压电流无缝缩放；F)高压阻断和电流传导；G)导热系数高；H)简化开关的新型光触发；i)不依赖于氧化层。与领先的高压Si和SiC基器件不同，这种新型光学单偏置器件具有抗噪声、增强可靠性和减少直接光产生的延迟。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SiC OA-GTO功率级和低压控制级之间的隔离。器件的光子调制实现了SiC OA-GTO器件动态控制，从而降低了延迟，改善了通断状态特性。

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.