Dan Rogers

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Biography: 

Current research

Link to publications.

My research activity is in the design and control of power electronics for electrical distribution and transmission systems, including energy storage, HVDC and FACTS devices. I also work on the development of power electronic systems more generally, including power density optimisation and active gate drives for industrial and transport applications. Some active areas of research are:

  1. Energy storage: The creation of power electronic systems capable of scaling to the independent management of millions of cells. This is recognition of the need to manage high-value energy storage cells (such as lithium-ion cells) proactively; systems of 10MW-1GW scale will require robust distributed management schemes that are tolerant of substantial cell-to-cell variation, can manage uneven cell degradation and cope with eventual cell failure as an on-going process during normal operation of the system. This work is coupled to collaborative efforts to develop whole-system modelling techniques that can be used to predict the performance of a range of energy storage solutions in realistic grid connection scenarios, particularly focussing on the impact of cell balancing control and the reliability of the power conversion system. See EPSRC projects Energy Storage for Low Carbon Grids, Capital Grant for Great Technologies and Multi-scale analysis for Facilities for Energy storage.
  2. Power electronics for transmission, distribution and microgrid systems: The design of ‘thin’ or ‘hybrid’ power electronic systems based on the observation that while power electronics provides extremely flexible control of electrical power, it is very challenging to beat traditional electrical grid plant, for example, relatively low-cost line frequency transformers (capable of 99.7% efficiency, lasting >30 years) and mechanical switches and circuit breakers (with an on-state efficiency of 99.99% or higher). A challenge is to develop hybrid systems that provide the valuable flexibility of ‘full’ power electronic solutions but also meet the demanding capital cost, efficiency and reliability requirements of the grid. This entails the design of systems that combine part-rated power electronic circuits with compact mechanical switches, custom magnetic components etc. as well as developing overall control schemes that coordinate operation of these components. See EPSRC projects Reconfigurable Distribution Networks and Resilient Hybrid Technology for High-Value Microgrids.
  3. HVDC: The design and operation of modular multi-level converters focussing on providing short-term overload capability by exploiting the thermal headroom of large power semiconductor devices. Design of control schemes for large HVDC grids used for the aggregation of renewable energy (particularly offshore wind power). See the FP7 ITN project Multi-terminal DC grid for offshore wind.
  4. Modelling and optimisation of power electronic systems: The development of analytical models of the power density scaling relationships of high-performance power electronic converters in a combined electrical, thermal and mechanical optimisation framework. This framework allows the construction of reduced-order models for the major converter components (inductors, capacitors, semiconductors and thermal management system) based on material physical properties associated with power converter design. When these models are constrained by a set of converter design specifications the framework can be used to explore the gravimetric or volumetric power density figures possible for a given converter. See EPSRC project Investigating the Power Density of Power Electronics and UK Centre for Power Electronics project Optimisable System-Level Thermal Models for Power Electronic Converters.
  5. Digital Active Gate Drives (AGD): This is an interesting cross-disciplinary area of work where that seeks to finely control the switching process of large power transistors (IGBTs) switching at a few tens of kHz using very high bandwidth (1GS/s+) digital signal processing systems. The aim is to achieve optimisation of switching behaviour on-line in large power converters by tracking load current, device temperature DC link voltage etc.

Brief academic history

Energy systems in the developing world

I made several trips to Zambia from 2011-2014 where, working with a team of PhD and undergraduate students, we built a solar photovoltaic and battery energy storage system to provide power for a community computer classroom and a local health post. We learnt several lessons about load growth and the value of even small amounts of electricity in places where there was none before. See trip report 1, report 2 and report 3 for some technical details, and the in-brief Ingenia article for a summary.

Researchers and students

(c) marks current

Postdoctoral Research Associates

  • Amir Eleffendi (c)
  • Lee Thomas (c)
  • Mauro Innocente
  • Alasdair Burchill (c)
  • Padmavathi Lakshmanan

PhD/DPhil students

Visiting scholars

  • Nisal Amarasinghe
  • Upul Dissanayake
  • Jose Dominguez-Garcia
Contact Details: 
Dr Dan Rogers
Department of Engineering Science
University of Oxford
Tel: +44 (0)1865 273109
Email: dan.rogers@eng.ox.ac.uk

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