Enhancement of Inductive Power Transfer (IPT) for Wireless EV Charging

通过使用包括电动汽车(EVS)在内的超低排放车辆(ULEV)实现道路交通的脱碳，被视为帮助英国实现其气候变化义务和改善空气质量的关键，尤其是在伦敦等大城市。然而，与化石燃料相比，最先进的电动汽车电池的能量密度要低得多(锂离子电池的能量密度为240瓦时/公斤，是汽油的2%)，这显著影响了行驶里程。在电池技术没有可预见的突破(到2035年能量密度增加4倍)的情况下，频繁和方便的电池充电是使电动汽车成为主要的脱碳交通工具的唯一途径。目前大多数电动汽车的快速充电过程需要司机将连接的电源插座连接到车辆上，这使得司机容易发生危险。有限的充电机会导致每次充电的停留时间较长，并导致里程焦虑。相反，能量可以通过空气中的时变磁场在一次电源侧(地面)和二次电池侧(机载)之间传输，称为感应功率传输(IPT)。由于没有物理连接，充电不会引起注意，也不会带来麻烦。这种模式将从在集中式充电中心进行不频繁的冗长充电转变为分布式充电场所自动进行充电。因此，充电事件可以无缝地融入常规车辆运行，成为日常后台生活的一部分，因此插件遗忘将永远不会再发生。升级集中式充电集线器基础设施的周期长、成本高，可以减少频繁充电降低放电深度，从而延长电池的使用寿命。缺乏人工干预的IPT可以使未来的电动汽车自主运行并为其他机器，如机器人、无人驾驶飞行器或水下飞行器(UAV、UUV)充电。这项研究首次将纳米晶芯线圈用于IPT应用，也是首次将频率和占空比控制与双有源电桥拓扑(DA-IPT)相结合。将探索新的控制算法，如MinAPPT和硬开关缓解技术，以及在DA-IPT的逆变器和整流器中使用SIC MOSFET，以提高未对齐充电条件下的功率密度和效率。使用DA-IPT拓扑和基于纳米晶芯的线圈的组合设计的多目标设计优化过程将为未来的开发和其他相关的电力电子研究而设计并不断改进。研究的目标是在垂直和横向不对准30%的情况下，效率达到92%或以上，功率密度为2kW/kg、4kW/dm~3或以上。将建造7.7千瓦(2级电动汽车充电)原型，并使用仿真模型和设计工具等可交付成果进行实验验证。11千瓦的原型是下一步具有潜在工业投资的项目。这项研究的成功将发掘和验证所提出的想法的理论价值，并为后续的研究奠定坚实的基础，包括V2G的双向功率流动、机械稳健性的提高、EMC以及未来适用的DA-IPT系统的客观抑制方法。

The decarbonisation of road transport through the use of ultra-low emission vehicles (ULEVs), including electric vehicles (EVs), is seen as critical to helping the UK achieve its climate change obligations and to improving air quality, particularly in major cities such as London. However, state-of-the-art batteries for EVs show much lower energy density compared to fossil fuels (240 Wh/kg energy density of Lithium-ion (Li-ion) battery, 2% of petrol's energy density), which significantly compromises the driving range. Without foreseeable breakthroughs (4 times energy density increase by 2035) in battery technology, frequent and convenient battery charging is the only way to enable EVs as the dominant means of decarbonised transportation. Most current fast and rapid charging process for EVs requires drivers to connect the tethered electrical outlet to the vehicle, leaving drivers prone to hazards. Limited charging opportunities cause a long dwell time of each recharge and range anxiety. In contrast, energy can be transferred between the primary source side (on-ground) to the secondary battery side (on-board) by using time-varying magnetic fields through the air, known as the inductive power transfer (IPT). The absence of physical connection offers unobtrusive and hassle-free charging. The paradigm will shift from infrequent lengthy charging at centralised charging hubs to distributed charging places conducting charging automatically. Therefore, charging events can be seamlessly integrated into regular vehicle operation and becomes part of daily background life thus plug-in forgetfulness will never happen again. The long lead-time and large cost of upgrading infrastructure for centralised charging hubs can be reduced and frequent charging reduces the discharge depth, which extends the lifetime of the battery. Lack of human intervention of IPT can enable future autonomous EV operation and charging other machines such as robots, unmanned aerial or underwater vehicles (UAVs, UUVs). This research is the first to use nanocrystalline cores based coils for IPT applications and also the first to combine frequency and duty ratio control with a dual-active bridge topology (DA-IPT). New control algorithms, such as MinAPPT and hard-switching mitigation techniques, will be explored, together with the use of SiC MOSFETs in both the inverter and rectifier of DA-IPT to improve the power density and efficiency in misaligned charging conditions. A multi-objective design optimisation process using a combined DA-IPT topology and nanocrystalline core based coils will designed and continuously improved for future development and other relevant power electronics research. The research aims to achieve 92% efficiency or above, at 30% vertical and lateral misalignment with a power density of 2 kW/kg, 4 kW/dm3 or above. A 7.7 kW (Level 2 EV charging) prototype will be built and experimentally validated with deliverables such as simulation models and design tools. An 11 kW prototype is the next step with potential industrial investment. The success of this research will exploit and validate the theoretical merits from proposed ideas and establish a solid foundation for continuous investigation, including bi-directional power flow for V2G, improvement of mechanical robustness, EMC and objective rejection methods of applicable DA-IPT systems in the future.