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Details of Grant 

EPSRC Reference: EP/P00914X/1
Title: Power flow control in future electric vehicles and dc microgrids with multiple energy sources
Principal Investigator: Dordevic, Dr O
Other Investigators:
Researcher Co-Investigators:
Project Partners:
BMW Infineon Technologies
Department: Engineering Tech and Maritime Operations
Organisation: Liverpool John Moores University
Scheme: First Grant - Revised 2009
Starts: 21 March 2017 Ends: 24 May 2018 Value (£): 100,727
EPSRC Research Topic Classifications:
Control Engineering Electric Motor & Drive Systems
Energy Storage Sustainable Energy Networks
EPSRC Industrial Sector Classifications:
Transport Systems and Vehicles
Related Grants:
Panel History:
Panel DatePanel NameOutcome
04 Oct 2016 Engineering Prioritisation Panel Meeting 4 October 2016 Announced
Summary on Grant Application Form
This research considers control of systems that contain several dc electric energy sources and an electric ac machine. It proposes utilisation of a multiphase machine (with a multitude of three-phase sub-windings) in such systems, with the idea of enabling arbitrary sharing of the energy between the sub-systems connected to the different sub-windings. The targeted applications are the future electric vehicles (EVs) and dc microgrid interconnection. The said machine is the propulsion motor in the former and the renewable energy generator in the latter case.

One way of overcoming the battery size problem in EVs is to design vehicles to use a multitude of different electric energy sources, such as batteries, fuel cells, flywheels, superconducting magnetic energy storage and photo-voltaic systems. If this is to be achieved, a suitable control strategy for the propulsion motor, which would rely on optimal utilisation of these sources, is required. The requirement is that the different sub-windings, connected to the different energy sources, can be controlled independently, so that simultaneous motoring and generating mode of operation of the different sub-windings can be realised. This will enable decoupled power flow control and hence lead to the optimal exploitation of the available energy resources, when observed from the overall system perspective. Independently controllable power sharing will enable transfer of energy from one source in the vehicle to the other in accordance with the external conditions and the driving regime (e.g. solar energy to charge the battery and/or a supercapacitor during vehicle's cruising, a supercapacitor to provide the energy boost during rapid accelerations and decelerations - thus reducing the required size of the battery).

Dc microgrids are foreseen as an important component of the future smart power systems. Commonly, microgrids contain a renewable energy generator, such as wind or hydro generator. Similarly to the EV scenario, the interconnection of dc microgrids, which will become possible through utilisation of the independent and decoupled power flow control of the renewable generator's three-phase winding sets, will eliminate the need to utilise additional power electronic converters (as the current state-of-the-art is) for this purpose. Controlled energy sharing enables simple "peak energy shaving" when the energy consumption peaks do not appear simultaneously in the interconnected microgrids. In simple words, using the proposed algorithms, a microgrid with a surplus of the energy may supply other microgirds that need more energy. Apart from power flow control, additional benefits of this solution are potential cost saving and existence of inherent galvanic isolation between different dc sub-systems.

The research will develop advanced control techniques for multiphase machines with multiple three-phase windings that will enable arbitrary circulation of the power through the machine's three-phase winding sets. This will be achieved by using two different electric machine modelling approaches. The first will use as the starting point a known approach, while the second one will be based on a new machine model transformation with power sharing coefficients that is to be developed in the project. Both approaches will yield models required to obtain subsequently high quality dynamic performance of the machine when used as a variable speed drive/generator. Once the two different approaches are fully developed and verified through the simulations, the final step will be experimental verification and comparison of the devised control strategies in laboratory conditions.

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Organisation Website: http://www.livjm.ac.uk