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MPhil in Engineering for Sustainable Development

global challenges, engineering solutions

Improve Power Efficiency by means of Designing and Testing of Power Conditioning and Impedance Matching Circuitry


Energy harvesting has witnessed a rapid increase of interest in both academic and industrial circles during the past decade. The decentralized and self-sustaining nature of energyharvesting provides a convenient on-board supplement to batteries for a prolonged lifetime of  remote and wireless devices. However, at the moment, there is a gap between the harvester  nd the application, namely, the power conditioning circuitry and electrical impedance matching. The ‘ideal’ result is that once connected to an application (i.e. a wireless sensor mote), the  harvester is able to provide power with minimal compromises in the mechanical-to-electrical interface. Hence, this dissertation looks at the ways in which we can improve power efficiency by means of SPICE design, as well as experimental testing of potential power conditioning and  impedance matching circuitry.

After experimental testing of power conditioning and impedance matching circuitry, the results show  that circuit models 3 and 5 produced results showing a good agreement with  experimental results, with a mean percentage error of 6.9% in peak voltages induced. The output voltages produced in the simulation showed results that are  relatively  good  agreement with  the  experiments, yielding  a  smoothed  ripple voltage which could be considered as an almost constant DC supply.

As for the comparison made between sinusoidal waveform (sine wave from function generator (FG)) and  piezoelectric vibrations energy harvester (V25W) experimental results, irregularities observed  between the aforementioned results validates the instability of vibrations i.e. non-linearities  compared to the simulated voltage source through sine wave.

Course Overview


The need to engage in better problem definition through careful dialogue with all stakeholder groups and a proper recognition of context.


An ability to work with specialists from other disciplines and professional groups acknowledging that technical innovation and business skills also must be understood, nurtured and combined as precursors to the successful implementation of sustainable solutions.


An understanding of mechanisms for managing change in organisations so future engineers are equipped to play a leadership role.


An awareness of a range of assessment frameworks, sustainability metrics and methodologies such as Life Cycle Analysis, Systems Dynamics, Multi-Criteria Decision making and Impact Assessment.