High-Density Active Silicon Carbide Power Electronics: Enabling Responsive Power Conversion

为了实现净零碳排放，必须开发提高能源转换效率和可靠性的技术，例如电动汽车的动力传动系统和快速充电器。考虑到这一点，重型电动汽车的电池尺寸更大（例如，在800 V和440 A时，电池功耗更高，为350千瓦时）和远程驾驶特性，要求无处不在地使用350千瓦的极快充电器，以避免在经济上合理的充电延迟。这些建议通过高频固态变压器（SST）直接连接到11千伏馈线，需要能量密集的快速电源模块。文献表明，宽带隙半导体器件，特别是碳化硅器件的出现，使我们能够提供超高效可靠的转换器，实现下一个飞跃。然而，由于高dV/dt、共模干扰和退化等问题，宽带隙电力电子技术目前发展缓慢。这意味着宽带隙器件的全部潜力还远未得到充分发挥。IEEE国际宽带隙功率半导体技术路线图（ITRW）指出，要释放这一潜力，必须在2028年之前突破这些限制。由于英国将在2030年之前禁止销售新的汽油和柴油发动机，从而引领汽车电气化，因此英国需要在本地开发这项技术，甚至更早，以保持在“推动电动革命”方面的全球竞争对手地位。对SiC器件的研究表明，它们容易逐渐退化，具有“记忆”效应，导致电热参数偏离数据表值。这可能导致长期操作失败。然而，证明了在一定条件下，如果器件受到特定的电和热条件，器件可以恢复到接近初始状态。简而言之，该提案旨在利用这些发现来探索使用非接触式传感器控制和逆转器件退化的方法，这些传感器将信息馈送到智能有源栅极驱动器，从而控制功率器件的恢复。为此，这项新研究者奖项目旨在使这些电源转换器的电力电子核心对操作条件和功能退化做出响应。这将通过关闭检测SiC器件变化和如何通过其门控制器件之间的环路来实现。这将允许SiC器件以更高的开关速度安全运行，从而提高效率，而不是当前数据表限制所允许的。这是因为数据表的标称值是保守的，以便考虑到每一种情况，而新的态势感知将允许在适当的时候安全地超过这些限制。这是非常重要的，特别是在SiC功率转换的情况下，因为虽然它成功地取代了硅，但众所周知，SiC的潜在性能比今天的系统高一个数量级。能够安全地突破这些标称限制将使汽车和飞机的转换器体积减少2倍或更多，并在风能和太阳能发电中带来类似的功率损失减少。也许最重要的是，当设备老化或过热时，它可以通过切换到更安全的驾驶模式来降低操作风险。例如，这将以更低的损坏风险产生更多的电力，从而降低海上风力发电的成本，并允许先发制人地进行维护。在未来，具有操作条件和退化意识的响应式功率转换可以让电动汽车检测到驱动故障的开始，并激活安全模式将人们送回家。

In pursuit of Carbon net-zero, it is imperative to develop technologies that enhance the efficiency and reliability of energy conversion, e.g. in drivetrain and rapid chargers of electric vehicles (EVs). To put this into context, the larger battery size (i.e. 350 kWh at 800 V & 440 A for higher consumption) and long-range driving nature of heavy-duty EVs mandate ubiquitous access to extremely fast chargers at 350 kW for financially justifiable charging delays. These are proposed to directly connect to 11 kV feeders by high-frequency solid-state-transformers (SST), needing energy-dense fast power modules. Literature indicates that the emergence of wide-bandgap semiconductor devices, especially Silicon Carbide devices, enables us to deliver ultra-efficient reliable converters that deliver the next leap.Wide-bandgap power electronics is, however, currently being slowed down due to issues such as high dV/dt, common-mode interference and degradations. This means the full potential of wide-bandgap devices is still far from being obtained. The IEEE International Technology Roadmap for Wide-Bandgap Power Semiconductors (ITRW) has indicated that to unlock this potential, these limitations must be broken-through by 2028. As the UK is leading toward automotive electrification with a ban on the sale of new petrol & diesel engines by 2030, the UK needs to develop this technology locally, and earlier than this, to remain a global competitor in 'driving the electric revolution'.Research on SiC devices has shown that they are prone to progressive degradations, with a 'memory' effect that leads to a drift of electrothermal parameters away from the datasheet values. This can lead to failures in long-term operations. Nevertheless, it is demonstrated that under certain conditions the devices can recover to close to the initial state, if the devices are subjected to specific electrical and thermal conditions. This proposal, in a nutshell, aims to take advantage of these findings to explore ways of controlling and reversing degradation in devices using non-contact sensors which feed information to smart, active gate drivers, which, in turn, control the recovery of the power devices.To this end, this New Investigator Award project aims to make the power electronic core of these power converters responsive to operating conditions and functional degradations. This will be achieved by closing the loop between detection of change in SiC devices and how devices are controlled via their gates. This would permit SiC devices to be operated safely at higher switching speeds and thus efficiencies, than current datasheet limits allow. This is because datasheet nominal values are conservative in order to take every situation into account, whereas new situational awareness will allow these limits to be safely exceeded when appropriate. This is so important, particularly in the case of SiC power conversion, because whilst it is successfully taking over from silicon, it is also known that the potential performance of SiC is over an order higher than today's systems. Being able to safely break through these nominal limitations will reduce converter volume in cars and aircraft 2x or more, and bring a similar reduction in power loss in wind and solar power generation. Perhaps most importantly, it will reduce operational risk, by changing to safer driving modes as devices age or overheat. For example, this will reduce the cost of offshore wind power generation by generating more power at a lower risk of damage, and allow maintenance to be pre-empted. In the future, responsive power conversion with awareness of operating conditions and degradation could allow electric vehicles to detect the onset of drive failure, and activate a safe mode to get people home.