CAREER: A Universal Block of "Series Connected SiC MOSFET" for Medium/High voltage converter

目前，电力电子系统在电动汽车、可再生能源、数据中心、医疗设备、照明和其他工业或消费应用中得到了广泛的发展。这些应用中的系统需要缩小系统组件，同时实现轻量化和高效率。电力电子系统的这些目标可以通过对功率模块的多种改进来实现，例如更低的损耗、更高的频率、更高的温度和小型化。为了突破这些对功率模块的需求，重要的是将器件材料从硅（Si）替换为硅碳（SiC）或氮化镓（GaN）等下一代材料。尽管随着市场对SiC技术采用的迅速增加，低压SiC功率器件有望取代硅器件，但在高压大功率应用中，硅器件仍占主导地位。本研究的目标是在现有商用器件技术的基础上开发高压大电流SiC模块，使基于SiC的半导体能够在高压大功率转换系统中使用。诸如提高效率，减少零件数量以及减小尺寸和重量等系统优势应该使该技术在这些应用中具有吸引力。该项目的综合性质也将支持多方面的研究培训计划，对研究生和本科生都有影响。该项目的成果将通过本科和研究生课程传播，为学生未来的职业生涯做好准备。本CAREER项目的目标是显著提高高压大功率转换系统的效率和功率密度。为了实现这一目标，本文提出的方法是用串联和并联的低压SiC mosfet （1.2kV, 1.7kV）取代高压Si IGBT （3.3kV, 4.5kV, 6.5kV）。具体而言，将开发具有良好的动态电压/电流共享和高可靠性的“串并联SiC MOSFET”标准块，以改变游戏规则并普遍适用。为了实现这一目标，值得注意的是，多个器件的串并联连接具有以下必须解决的设计挑战：不均匀的静态和动态电压/电流共享，这通常是由于器件之间的参数变化、门回路寄生差异、门电阻容差、隔离电平差异和信号传输通道到通道的延迟；对传统短路失饱和保护的抗扰性；由于设备之间连接的母线所产生的额外环路电感而引起的过电压振铃。为了克服这些挑战，建议将先进的方法集成到区块中。标准模块的可行性和优势将在降功率中压驱动、中压光伏电源转换、极限快速充电（XFC）站中压电源转换原型中得到验证。除此之外，该技术还将应用于GaN器件，形成与单SiC MOSFET竞争的高压大电流GaN模块，并将展示其效率/密度优势。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

CAREER: A Universal Block of Series-Parallel Connected SiC MOSFETs for High Voltage High Power Conversion System Power electronic systems are widely developed nowadays in electrical vehicles, renewable energy, data center, medical equipment, lighting, and other industrial or consumer applications. The systems in these applications need to shrink system components and achieve light weight and high efficiency simultaneously. These goals of power electronic systems can be accomplished by multiple improvements of power modules such as lower loss, higher frequency, higher temperature and downsizing. In order to make breakthrough in these demands for power modules, it is important to replace the device material from Silicon (Si) to the next generation ones such as Silicon-Carbon (SiC) or Gallium Nitride (GaN). Although the low voltage SiC power device is expected to replace the Silicon device with the rapid increase of market adoption of SiC technology, Silicon device are still dominant in high-voltage high-power applications. The goal of this research is to develop the high voltage high current SiC module based on the existing commercially available device technology to enable the use of SiC-based semiconductors in the high-voltage high-power conversion systems. System benefits such as improved efficiency, reduced part count along with reduced size and weight should make this technology attractive for adoption in these applications. The comprehensive nature of this project will also support a multi-faceted program of research training, with impact at both the graduate and undergraduate levels. The outcome of this project will be disseminated through the undergraduate and graduate courses to prepare the students for future careers. The goal of this CAREER project is to significantly improve the efficiency and power density of high-voltage high-power conversion systems. To achieve the goal, the proposed approach is to replace the high voltage Si IGBT (3.3kV, 4.5kV, 6.5kV) by series and parallel connected low voltage SiC MOSFETs (1.2kV, 1.7kV). Specifically, a game changing and universally applicable standard block of "series-parallel connected SiC MOSFET" will be developed with excellent dynamic voltage/current sharing and high reliability. In order to reach this objective, it is worth noting that the series-parallel connections of multiple devices have the following design challenges that must be addressed: unequal static and dynamic voltage/current sharing which is normally due to the part-to-part device parameter variations, the gate loop parasitic differences, the gate resistor tolerance, the isolation level differences and the signal transmission channel to channel delays; immunity to the conventional de-saturation protection for short-circuit failure; excessive voltage ringing due to the additional loop inductance contributed by the connected bus bars between devices. The advanced methods are proposed to be integrated into the block to overcome these challenges. The feasibility and advantages of the standard block will be demonstrated in the power-down-scaled medium voltage drive, medium voltage PV power conversion, Extreme Fast Charging (XFC) station medium voltage power conversion prototypes. Except for that, the technology will be applied to GaN device to form high voltage high current GaN module competing with the single SiC MOSFET as well and the efficiency/density benefits will be demonstrated.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.