Analysis of Power Quality in Complex DC Power Networks

Protecting the environment for future generations to enjoy is a key priority for the international community. Emissions from all forms of transport systems, and land based power generation are being addressed by ambitious targets, such as decarbonising both the UK's road transport and power generation sectors by 2050 (A strategy for ultra-low emission vehicles in the UK, 2013, Dept. of Trans., & Delivering our low carbon future, 2011, HM Gov.), and the Flightpath 2050 target of a 75% reduction in CO2 emissions per passenger kilometre relative to an aircraft built in 2000 (Europe's vision for aviation, 2011, EU Comm.). A key challenge to achieving these targets is developing low carbon technologies, and this is being enthusiastically embraced by researchers, with power electronic based systems being widely proposed due to their high efficiency, controllability, flexibility and reliability. This high concentration of power electronic converters, often in small DC networks, can adversely affect system stability; power converters employ sophisticated control and protection functions which are sensitive to changes on the network, these changes can easily be triggered by normal operation of another power converter, and can result in another power converter unnecessarily going offline, which may compromise network security. This project aims to develop a fundamental understanding of power quality in complex DC power networks, and then examine a diverse range of real world scenarios to evaluate power quality using a 100kW DC power network demonstrator system. A key outcome of this project will be to enable systems which have high concentrations of power converters to be designed with confidence, enabling low carbon technologies to be fully exploited in future electric vehicles, aircraft and smart grids.

The principal beneficiaries of this research will be system designers of low carbon transport applications (aircraft, marine, automotive, commercial vehicles and rail) as well as future smart grids. The designers will have the ability to evaluate the stability of new configurations of complex DC power networks with high concentrations of power converters. For the transport sector this will allow the more-electric concept to be realised, bringing system level benefits of reduced fuel consumption per passenger-km, which will lower the environmental impact. Understanding power quality in complex DC power network will enable more-electric concepts to be fully embraced, enabling both a significant increase in the number of more-electric vehicles and also an increase in the number of power converter systems, which will yield manufacturing opportunities for diverse areas of the UK supply base across the entire transport sector. Society in general will benefit from lower cost travel and reduced emissions, which will reduce the environmental impact and enable a more sustainable use of resources. Similar benefits will be apparent in smart grids, where UK manufacturing and consumer load / source revenue opportunities will both be enhanced by higher uptake of the technology.

The applicant's well-established links with Rolls-Royce and the company's involvement in the proposed project will provide a natural mechanism for technology transfer into the aerospace and marine sectors. In addition the Power Conversion Group has well established links with companies in the automotive sector such as Prodrive. Beyond this, commercial exploitation of the research, will be handled by the University's Knowledge and Technology Transfer Office. Once IP from the project has been protected then the material will be published in international conferences and journals. The publications will stimulate further research in the transport sector, smart grid and associated application areas by academic and industrial researchers. Dissemination events are planned at other UK universities and in industry to broaden knowledge of the work and stimulate further research and collaborations in the area. A dedicated project website will be used to support dissemination to the public and wider scientific community, and the project will link with the university wide themes of Energy at Manchester and the Aerospace Research Institute (UMARI).