Integrated Drive System with Modularised Energy Storage for Automotive Applications

点击翻译按钮获取中文摘要

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