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Miss Sophie Draper

Research Postgraduate – Electrical Power Node

Research Postgraduate – Electrical Power Node in the Department of Engineering 



Sophie (she/her) is a PhD researcher specialising in Electrical Engineering in the Department of Engineering. Her PhD investigates and tests unconventional generator possibilities for wind turbine applications. The PhD project is funded by the Engineering and Physical Sciences Research Council as part of UK Research Innovation. She holds a BEng (Hons) in General Engineering, with a Mechanical specialism. Sophie’s MSc degree in New and Renewable Energy Engineering from Durham University was sponsored by Ørsted (formerly DONG Energy). Her research project investigated the viability of using ferrites to replace rare earth (Neodymium Iron Boron) permanent magnets in 5-10MW Permanent Magnet Synchronous Generators (PMSG) by testing and optimising three flux concentrating topologies. Sophie is a member of the Durham Energy CDT and Engineering Department Strategic Advisory Board.

Whilst Sophie’s research focuses on electrical machines and offshore wind, she also has an interest in energy use within buildings, with industry experience as a Building Services Engineer. Sophie recently completed a side-project with the Church of England and Energy CDT, providing recommendations to decarbonise a notable Durham Church. Sophie was a member of the Durham Castle Middle Common Room Executive Committee for two years in the roles of Communications Officer and Ball Chair. Sophie was lead organiser of the 2021 Castle Charity Ball. Sophie was a finalist in the 2020 Durham Student Art Prize: Heroism.

Presentations and Conferences
  • EAWE (European Academic Wind Energy) 15th PhD Seminar, Nantes 2019
  • Energy CDT May 2020
  • UKMS (UK Magnetics Society) August 2020
  • Durham Castle MCR Sunday Seminar Series January 2021
  • DSE (Durham Student Energy) February 2021
  • Energy CDT May 2021
  • WESC (Wind Energy Science Conference) Hannover 2021
  • Castle Conference: Power, Privilege and Possible Futures 2021
  • Durham Castle MCR Sunday Seminar Series November 2021
Research Project

The direct drive permanent magnet synchronous generator (DD-PMSG) is the favoured offshore multi-MW wind turbine (WT) generator solution due to its availability and high power density. Rapid installation of PMSGs in the last 5 years within Europe has meant they have already overtaken the total number of alternating current induction WT generators installed offshore, such as the SCIG or DFIG. However, PMSGs are problematic due to the large quantities of rare-earth permanent magnets required which are costly with geo-political concerns. Furthermore, synchronous DD machines require fully rated converters which are expensive and contribute to significant downtime if they fail. The popular commercial transition to using PMSG WTs alongside the high costs of machine testing has encouraged further conservatism in the design of generators. Lack of bespoke WT drive train and generator design could impact potential levelised cost of energy, particularly with emerging technologies, including floating offshore WTs. Certain unconventional electrical machines have characteristics which could make them advantageous in WT applications; such as the brushless doubly fed induction machine and ferrite based multistage axial flux machines. However, electrical machines for high power WT applications are often not compared quantitatively or objectively within research. A far improved comparison can be achieved by fixing the desired power output of the machine and modelling the generators using the same method across different machines.

Sophie is thus producing a comparison model featuring a number of parallel steady-state analytical sub-models. Design equations are derived from the respective per-phase electrical equivalent circuit (EEC). Peak values for flux density in the machines are identified in a recurring manor when the simulations are running using a link to static finite element analysis (FEA) in Simcenter MAGNET. Multi-objective optimisation of the machines is implemented using the genetic algorithm. The models have so far shown to produce accurate results when conducting objective comparisons between multi-MW novel generators and the commercially favoured generators in non-exhaustive process.

Research interests

  • Design and Optimisation of electrical machines
  • Electrical power conversion
  • Offshore wind turbines and farms