Dr Geoff V. Merrett
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Two Papers Accepted for Publication in IEEE Transactions

26th September 2011

Our paper on supercapacitor modelling
Our paper on supercapacitor modelling
We have recently had two papers related to our work on Energy Harvesting electronics accepted for publication in the IEEE Transactions on Circuits and Systems. Both publications are a result of the EPSRC project on 'Holistic Energy Harvesting'.

The first paper, 'Accurate Supercapacitor Modeling for Energy-Harvesting Wireless Sensor Nodes' investigates supercapacitors, often used in energy-harvesting wireless sensor nodes (EH-WSNs) to store harvested energy. Until now, research into the use of supercapacitors in EH-WSNs has considered them to be ideal or over-simplified, with non-ideal behavior attributed to substantial leakage currents. In this brief, we show that observations previously attributed to leakage are predominantly due to redistribution of charge inside the supercapacitor. We confirm this hypothesis through the development of a circuit-based model which accurately represents non-ideal behavior. The model correlates well with practical validations representing the operation of an EH-WSN, and allows behavior to be simulated over long periods..

The second paper, 'Photovoltaic Sample-and-Hold Circuit Enabling MPPT Indoors for Low-Power Systems' presents an ultra low-power maximum power point tracking (MPPT) circuit with a novel sample-and-hold and cold-start arrangement, enabling efficient indoor MPPT (which has not been reported, or considered possible, before). The circuit is validated in practice, and the sample-and-hold behaviour analysed using real light data.

For more information, click here.

Other Articles

Energy Harvesting Book Chapter
30th June 2010
The Cover of the Book
My book chapter on "Wireless Devices and Sensor Networks," that I co-authored with Dr Alex Weddell and Dr Nick Harris has just been published! The book, titled "Energy Harvesting for Autonomous Systems", is published by Artech House, and edited by Professor Neil White and Dr Steve Beeby. The majority of my chapter is (at least currently) available to read on Google Books. The chapters of the book are: Introduction Wireless Devices and Sensor Networks Photovoltaic Energy Harvesting Kinet... [more]

Haptics Research in Government Report
11th July 2011
FAST Government Report, 2011
Our research on haptic devices for stroke rehabilitation has been featured in an annual government report on assistive technology. Our bit can be found on page 51 of the report (follow the link at the bottom of this news item). The report is prepared by FAST (the Foundation of Assistive Technology), and is an annual publication by the Department of Health (UK Government). The report has a number of uses (including giving researchers an overview of other work in the field, and service provider... [more]

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