Integrated Drive System with Modularised Energy Storage for Automotive Applications

汽车电动化是行业的重大转变，带来了丰富的机遇。标准拓扑结构的电动汽车动力总成是基于一个由大型单电池组供电的两电平逆变器。需要单独的板载充电器、DC-DC转换器和电池管理系统来完成电力电子产品包。虽然电力电子与电机的集成正在积极研究中，但它也可以在电池组内较不苛刻的环境中远离电机进行集成。模块化多电平转换器不仅可以实现模块化电池组和电力电子设计，还可以将逆变器和板载充电器集成到电池组本身中。由于成本和效率仍然是当今和可预见的未来汽车制造商面临的最大挑战，这项研究有可能提供一组不同的设计限制，这可能有利于某些应用。记录并量化汽车动力总成应用中对此类系统的要求和约束2)了解和量化特定拓扑给动力总成成本和效率带来的优点和缺点观察行为：1)模拟TLI和MMC拓扑的行为(电气和热)，以复制文献综述中的观察结果2)开发辅助模型，以帮助模拟多个行业标准驱动周期中的拓扑行为3)确定各种使用案例的最佳拓扑，并确定它们之间的关系创建理论以匹配状态并预测其他状态下的系统行为：1)选择一个有希望的候选2)将此与预测的不良使用案例进行比较(避免假阴性)3)将此与预测的不适合的使用案例进行比较(避免假阴性)测试系统在其他状态下的运行情况并验证预测：1)构建两个候选拓扑的原型并验证它们是否满足要求集(优先考虑第一个候选拓扑)2)使用原型驱动器和负载在HIL试验台上验证仿真结果目的是研究低成本低电压GaN基器件在模块化多电平转换器拓扑中的使用，以确定它们在汽车动力总成应用中的可行性。主要焦点将放在高压、大功率、重型动力总成上。该设计已用于高压直流输电线路，随着一些汽车供应商已经提供基本的3电平变流器，该设计寻求使用串联的低压开关，以获得高压操作能力。研究表明，这些拓扑的更复杂版本能够同时承担逆变器和车载充电器的职责，同时作为电池组的组成部分。研究在TRL3进行，在那里进行分析和实验关键功能和/或特性概念验证工作。这是EPSRC规定的资金TRL职权范围的上端。这项研究的主题是符合AAPS CDT职权范围的汽车电气化，这一概念潜在地允许降低汽车部件成本，更好地管理电池的充电状态和热封，并通过进一步将电子和电池集成到模块化系统中而有利于设计

Vehicle electrification is a major shift in industry bringing a wealth of opportunities. Standard topology EV Powertrains are based on a two level inverter fed by a large single battery pack. Separate onboard charger, DC-DC converter and battery management systems are needed to complete the Power Electronics package. While integration of power electronics with the motor is under active research, it can also be integrated away from the motor in a potentially less harsh environment within the battery pack. Modular Multilevel Converters have the potential not only to allow for modular battery pack and power electronics design but also integration of the Inverter and Onboard Charger within the battery pack itself. As cost and efficiency continue to be the biggest challenges facing vehicle manufacturers today and for the foreseeable future, this research has the potential to offer a different set of design constraints which may benefit certain applications.The aims and objectives areLiterature review: 1) Understand, document and quantify the requirements and constraints placed upon systems like this in an automotive powertrain application2) Understand and quantify the benefits and drawbacks brought to powertrain costs and efficiency by the particular topologyObserve Behaviour:1) Simulate behaviour (Electrical and Thermal) of TLI and MMC topologies (Various submodule designs and number of levels) to replicate observations in Literature review2) Develop auxiliary models to assist in simulating behaviour of topologies over a number of industry standard drive cycles3) Determine optimum topologies for various use-cases and ascertain how these relate to each otherCreate theory to match states and predict system behaviour in other state:1) Pick a promising candidate topology from the above and use simulation to predict operation under new use case2) Compare this against a predicted bad performer (Avoid false positives)3) Compare this against a predicted unsuited use case (Avoid false negatives)Test system in other state and validate predictions:1) Prototype the two candidate topologies and verify they meet the requirements set (Priority on first candidate)2) Validate the simulation results on HiL rig using prototype drives and loadsThe aim is to research the use of low cost low voltage GaN based devices in modular multilevel converter topologies to ascertain their viability in automotive powertrain applications. The main focus would be on high voltage high power heavy duty powertrains. Already used in HVDC power transmission lines, and with some automotive suppliers offering basic 3 level converters already, the design seeks to use low voltage switches in series, to gain High Voltage operating capability. Research has shown more complex versions of these topologies able to simultaneously take on duties of Inverter and on board charger while being an integral part of the battery pack.The research carried out is at TRL3 where analytical and experimental critical function and/or characteristic proof-of concept work is undertaken. This is at the upper end of the EPSRC's defined funding TRL remit. The theme of the research is vehicle electrification in line with the AAPS CDT remit and the concept potentially allows for lowering vehicle component costs, better managing the battery state of charge and thermal envelope, as well as benefiting design by further integrating electronics and battery into modular systems