Ultrawide Bandgap AlGaN Power Electronics - Transforming Solid-State Circuit Breakers (ULTRAlGaN)

迫切需要新的电力电子技术来支撑向净零的过渡。联合国政府间气候变化专门委员会在其2021年发布的科学报告中强调了我们地球面临的迫在眉睫的风险，称我们目前的状况是人类驱动的全球变暖的红色代码。在可再生发电系统中部署电力电子设备，可以实现对电网的智能控制和高效的能源利用。交通运输也是如此，这反过来将支持大幅减少目前全球浪费的72%的一次能源消耗。在这项计划拨款(PG)中，我们开发了变革性的下一代氮化铝(AlGaN)固态断路器(SSCB)，其效率大大提高，电压范围更大，适用于许多KV，与继续使用当前技术相比，实现了预期的全球节能20%。断路器是安全、可靠的电力系统的关键部件，包括电力电子密集型电网，但需要在性能上进行阶梯式变化。根据主要电力电子公司ABB/日立能源的说法，SSCB是“下一代电力基础设施中最薄弱的一环”。市场上现有的机械断路器响应时间较慢，有可能损坏敏感设备。基于硅(Si)的SSCB的替代使用，虽然提供了比机械断路器(&gt；100微秒)更高的开关速度(&lt；1微秒)，并提供了高性能配电所必需的快速电路保护，但目前受到高导通损耗的影响，单个芯片的安全运行通常最多限制在4-5千伏。在越来越复杂和多样化的应用领域，包括电动飞机和船舶，需要更高的电压范围。例如，如果仅在全球邮轮行业实施，硅基SSCB的低效将导致每年额外高达600万吨的二氧化碳排放。该公司的愿景和抱负是通过开发新的SSCB来解决目前电力电子领域的障碍。使用超宽带隙AlGaN SSCB可以在很大程度上消除现有技术中的限制，这种超宽带隙AlGaN SSCB的效率比现有商业高压器件(如硅绝缘栅双极晶体管和碳化硅(SiC)金属氧化物半导体场效应晶体管)保守地提高了100倍，从而实现了高效、紧凑、冷却要求最低的SSCB。预计在20年内，这些高效的超宽带隙AlGaN电力电子元件将取代所有其他技术，如用于大电流高压用途的硅和碳化硅，例如在火车、海运和飞机等配电和运输领域，帮助实现碳中和社会。使用AlGaN带来巨大好处的潜在物理原因是，与Si(1.1 eV)和SiC(3.2 eV)相比，AlGaN的带隙(高达6.2 eV)要大得多。AlGaN的常用电力电子学优点系数(即材料对电力电子设备的适用性)接近1,800，而Si为1，SiC为340，这使得电力电子将能够提供一场革命。许多相互关联的技术挑战需要解决，包括AlGaN材料的生长，以及实现足够大的层厚度的方法，以及开发和制造新的器件概念，以实现高性能和可靠的AlGaN SSCB。PG将由变革性设备原型的实现推动，在PG过程中不断增加的复杂性、挑战和创新，最终推动英国在这一领域的研究转向最终应用原型。高功率应用的空间是巨大的，开发将通过让终端用户参与SSCB原型的共同创造角色来指导。

There is an urgent need for new power electronic technologies to underpin the transition to net zero. The imminent risks for our planet have been highlighted by UN's Intergovernmental Panel on Climate Change calling our current status 'code red' for human driven global heating in its scientific report published in 2021. Deploying power electronics in renewable generation systems enables smart control of grid networks and efficient energy utilization. This is also true of transportation, which in turn will support a dramatic reduction of the 72% of global primary energy consumption currently wasted world-wide.In this programme grant (PG), we develop a transformative next generation of Aluminium Gallium Nitride (AlGaN) Solid-State Circuit Breakers (SSCBs), with greatly improved efficiency and greater voltage range, to many kVs, enabling anticipated global energy savings >20% compared to continuing with current technologies. Circuit breakers are critical components for safe, reliable electrical power systems, including for power-electronics-dense grids, but a step-change in performance is needed. According to the major power electronics company ABB / Hitachi Energy, SSCBs are 'the weakest link in next-generation electricity infrastructure'. The slow response time of existing mechanical circuit breakers available on the market risks damaging sensitive equipment. The alternative use of Silicon (Si) - based SSCBs, although providing superior switching speed (<1 microseconds) versus mechanical circuit breakers (>100 microseconds), and offering the fast circuit protection critically needed for high-performance power distribution, presently suffer from high conduction losses and are often limited at best to 4-5 kV safe operation for a single chip. Higher voltage ranges are required in increasingly more complex and varied application areas including electric planes and ships. For example, Si-based SSCB inefficiencies would contribute up to an additional 600 Mtons of CO2 emissions per year if implemented in the global cruise liner industry alone.The vision and ambition is to address current roadblocks in power electronics by developing new SSCBs. The limitations in existing technologies can be largely eliminated using ultrawide bandgap AlGaN SSCBs, which conservatively have a 100x improvement in efficiency compared to existing commercial high-voltage devices such as Si insulated-gate bipolar transistors and Silicon Carbide (SiC) metal oxide semiconductor field effect transistors, to enable efficient, compact SSCBs with minimal cooling requirements. In 20 years, it is expected that these highly efficient ultrawide bandgap AlGaN power electronic components will have displaced all other technologies such as Si and SiC for high-current high-voltage uses, e.g. in power distribution and transportation such as in trains, maritime and planes, helping enable a carbon neutral society. The underlying physical reason for the great benefit of using AlGaN is its much greater bandgap (up to 6.2 eV) compared to Si (1.1 eV) and SiC (3.2 eV). The commonly used power electronics Baliga Figure of Merit, i.e. the suitability of a material for power electronics, of AlGaN is nearly 1,800 compared to 1 for Si and 340 for SiC, enabling a revolution in what power electronics will be able to deliver.Many interlinked technological challenges need to be addressed, including AlGaN materials growth, and methods to enable large enough layer thicknesses, alongside the development and fabrication of new device concepts to achieve high performance and reliable AlGaN SSCBs. The PG will be driven by the realization of transformative device prototypes, with ever increasing complexity, challenge and innovation during the course of the PG, ultimately driving UK research in this area towards end-application prototypes. The high-power application space is huge, and developments will be steered by involving end-users in a co-creation role for the SSCB prototypes.