Publications
390 results found
Boyle D, Kiziroglou ME, Mitcheson P, et al., 2016, Energy provision and storage for pervasive computing, IEEE Pervasive Computing, Vol: 15, Pages: 28-35, ISSN: 1536-1268
Soon, pervasive computers will enormously outnumber humans. Devices requiring sufficient energy to operate maintenance-free for periods of years and beyond render today's technologies insufficient. With the gap between energy requirements of embedded systems and achievable levels of harvested power reducing, viable hybrid energy and power management subsystems have emerged that combine harvesting with finite, rechargeable energy buffers. Coupled with advances in wireless power transfer and energy storage, the authors suggest that an energy design space is emerging. There are, as yet, no tools or systematic methods for design space exploration or engineering in this context. It's important to develop such a methodology, and critical to link it with methodologies for system design and verification. The authors discuss key factors such an energy design methodology should incorporate, including size, weight, energy and power densities; mobility; efficiencies of harvesters and buffers; time between charges, (dis)charge speeds, and charge cycles; and availability and predictability of harvestable energy. This article is part of a special issue on energy harvesting.
Pu SH, Darbyshire DA, Wright RV, et al., 2016, RF MEMS Zipping Varactor With High Quality Factor and Very Large Tuning Range, IEEE ELECTRON DEVICE LETTERS, Vol: 37, Pages: 1340-1343, ISSN: 0741-3106
Fu H, Cao K, Xu R, et al., 2016, Footstep energy harvesting using heel strike-induced airflow for human activity sensing, 13th IEEE International Conference on Wearable and Implantable Body Sensor Networks (BSN), Publisher: IEEE, Pages: 124-129, ISSN: 2376-8886
Body sensor networks are increasingly popular in healthcare, sports, military and security. However, the power supply from conventional batteries is a key bottleneck for the development of body condition monitoring. Energy harvesting from human motion to power wearable or implantable devices is a promising alternative. This paper presents an airflow energy harvester to harness human motion energy from footsteps. An air bladder-turbine energy harvester is designed to convert the footstep motion into electrical energy. The bladders are embedded in shoes to induce airflow from foot-strikes. The turbine is employed to generate electrical energy from airflow. The design parameters of the turbine rotor, including the blade number and the inner diameter of the blades (the diameter of the turbine shaft), were optimized using the computational fluid dynamics (CFD) method. A prototype was developed and tested with footsteps from a 65 kg person. The peak output power of the harvester was first measured for different resistive loads and showed a maximum value of 90.6 mW with a 30.4 Ω load. The harvested energy was then regulated and stored in a power management circuit. 14.8 mJ was stored in the circuit from 165 footsteps, which means 90 μJ was obtained per footstep. The regulated energy was finally used to fully power a fitness tracker which consists of a pedometer and a Bluetooth module. 7.38 mJ was consumed by the tracker per Bluetooth configuration and data transmission. The tracker operated normally with the harvester working continuously.
Pillatsch P, Yeatman EM, Holmes AS, et al., 2016, Wireless power transfer system for a human motion energy harvester, Sensors and Actuators A: Physical, Vol: 244, Pages: 77-85, ISSN: 1873-3069
Human motion energy harvesting as an alternative to battery powering in body worn and implanted devices is challenging during prolonged periods of inactivity. Even a buffer energy storage system will run out of power eventually if there is no external acceleration to the harvester. This paper presents a method to actuate the rotor inside a previously presented rotational piezoelectric energy harvester wirelessly via a magnetic reluctance coupling to an external driving rotor with one or more permanent magnet stacks attached. This makes it possible to recharge a battery or super-capacitor even if a patient is not moving. The use of a permanent magnet coupling has potential advantages compared to traditional inductive or ultrasonic methods, e.g. in terms of tissue damage and transmission depth. Simulation results show the achievable coupling torque for different configurations of magnet geometries and relative positions between the driving magnet stack(s) and the harvester. It is shown that using a single magnet stack yields better results than using two diametrically opposite stacks. Measurements are performed with different magnets, driving frequencies and orientations of the harvester. The results are discussed and successful energy transfer was achieved regardless of the orientation of the device with respect to gravity, which is desirable for real world applications. Lateral misalignment between the harvester and the driving magnet can also be overcome. The largest distance of power transfer reached was 32 mm with the largest magnets tested, and the optimal power output into a resistive load was over 100 μW at a frequency of 25 Hz. The functional volume of the harvester is 1.85 cm3 – similar to the size of a wristwatch.
Goverdovsky V, Yates DC, Willerton M, et al., 2016, Modular Software-Defined Radio Testbed for Rapid Prototyping of Localization Algorithms, IEEE Transactions on Instrumentation and Measurement, Vol: 65, Pages: 1577-1584, ISSN: 1557-9662
A fully synchronized modular multichannel software-defined radio (SDR) testbed has been developed for the rapid prototyping and evaluation of array processing algorithms. Based on multiple universal software radio peripherals, this testbed is low cost, wideband, and highly reconfigurable. The testbed can be used to develop new techniques and algorithms in a variety of areas including, but not limited to, direction finding, source triangulation, and wireless sensor networks. A combination of hardware and software techniques is presented, which is shown to successfully remove the inherent phase and frequency uncertainties that exist between the individual SDR peripherals. The adequacy of the developed techniques is demonstrated through the application of the testbed to super-resolution direction finding algorithms, which rely on accurate phase synchronization.
Kiziroglou ME, Elefsiniotis A, Kokorakis N, et al., 2016, Scaling and super-cooling in heat storage harvesting devices, Microsystem Technologies, Vol: 22, Pages: 1905-1914, ISSN: 0946-7076
Aircraft sensors are typically cable powered, imposing a significant weight overhead. The exploitation of temperature variations during flight by a phase change material (PCM) based heat storage thermoelectric energy harvester, as an alternative power source in aeronautical applications, has recently been flight tested. In this work, the applicability of this technology to use cases with smaller and larger size specifications is studied by fabrication, testing and analysis of a scaled-down and a scaled-up prototype. Output energy of 4.1 J/g of PCM from a typical flight cycle is demonstrated for the scaled-down device, and 2.3 J/g of PCM for the scaled-up device. The higher energy density of the scaled down prototypes is attributed to the reduction in temperature inhomogeneity inside the PCM. The impact of super-cooling on performance is analyzed by employing a simulation model extended to include super-cooling effects. It is found that super-cooling may be beneficial for scaling down, in applications with slow temperature fluctuations.
Fu H, D'Auria M, Dou G, et al., 2016, A dynamic regulating mechanism for increased airflow speed range in micro piezoelectric turbines, 2016 IEEE 29th International Conference on Micro Electro Mechanical Systems (MEMS), Publisher: IEEE, Pages: 1220-1223
The paper reports the design and fabrication of amicro-planar spring for a dynamic regulating mechanismto decrease the cut-in (start-up) airflow speed of apiezoelectric turbine. This mechanism is implemented byadjusting the magnetic coupling between the turbine rotorand a piezoelectric cantilever using the spring. Variedspring shapes and dimensions were analyzed with the finiteelement method (FEM) to optimize the structure. A microspring with an ultra-low spring constant of 0.78 N/m wasfabricated from titanium foil by laser machining. Thespring was installed into a miniaturized air turbine toachieve the self-regulation. The cut-in speed was 2.34 m/s,showing a 30% improvement against a non-regulatedturbine.
Fu H, Xu R, Seto K, et al., 2015, Energy Harvesting from Human Motion Using Footstep-Induced Airflow, PowerMEMS, Pages: 012060-012060
This paper presents an unobtrusive in-shoe energy harvester converting foot-strike energy into electricity to power wearable or portable devices. An air-pumped turbine system is developed to address the issues of the limited vertical deformation of shoes and the low frequency of human motion that impede harvesting energy from this source. The air pump is employed to convert the vertical foot-strike motion into airflow. The generated airflow passes through the miniaturized wind turbine whose transduction is realized by an electromagnetic generator. Energy is extracted from the generator with a higher frequency than that of footsteps, boosting the output power of the device. The turbine casing is specifically designed to enable the device to operate continuously with airflow in both directions. A prototype was fabricated and then tested under different situations. A 6 mW peak power output was obtained with a 4.9 Ω load. The achievable power from this design was estimated theoretically for understanding and further improvement.
Fu H, Yeatman EM, 2015, A Miniature Radial-Flow Wind Turbine Using Piezoelectric Transducers and Magnetic Excitation, PowerMEMS, Pages: 012058-012058
This paper presents a miniature radial-flow piezoelectric wind turbine for harvesting airflow energy. The turbine’s transduction is achieved by magnetic “plucking”of a piezoelectric beam by the passing rotor. The magnetic coupling is formed by two magnets on the beam’s free end and on the rotor plate. Frequency up-conversion is realized by the magnetic excitation, allowing the rotor to rotate at any low frequency while the beam can vibrate at its resonant frequency after each plucking. The operating range of the device is, therefore, expanded by this mechanism. Two arrangements of magnetic orientation have been investigated, showing that the repulsive arrangement has higher output power. The influence of the vertical gap between magnets was also examined, providing guidance for the final design. A prototype was built and tested in a wind tunnel. A peak power output of 159 μW was obtained with a 270 kΩ load at 2.7 m/s airflow speed. The device started working at 3.5 m/s and kept operating when the airflow speed fell to 1.84 m/s.
Fu H, Yeatman EM, 2015, A miniaturized piezoelectric turbine with self-regulation for increased air speed range, Applied Physics Letters, Vol: 107, ISSN: 1077-3118
This paper presents the design and demonstration of a piezoelectric turbine with self-regulation for increased air speed range. The turbine's transduction is achieved by magnetic “plucking” of a piezoelectric beam by the passing rotor. The increased speed range is achieved by the self-regulating mechanism which can dynamically adjust the magnetic coupling between the magnets on the turbine rotor and the piezoelectric beam using a micro-spring. The spring is controlled passively by the centrifugal force of the magnet on the rotor. This mechanism automatically changes the relative position of the magnets at different rotational speeds, making the coupling weak at low airflow speeds and strong at high speeds. Hence, the device can start up with a low airflow speed, and the output power can be ensured when the airflow speed is high. A theoretical model was established to analyse the turbine's performance, advantages, and to optimize its design parameters. A prototype was fabricated and tested in a wind tunnel. The start-up airflow speed was 2.34 m/s, showing a 30% improvement against a harvester without the mechanism.
Kiziroglou ME, Boyle D, Wright SW, et al., 2015, Acoustic energy transmission in cast iron pipelines, The 15th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS 2015), Publisher: Institute of Physics (IoP), Pages: 1-5, ISSN: 1742-6588
In this paper we propose acoustic power transfer as a method for the remote powering of pipeline sensor nodes. A theoretical framework of acoustic power propagation in the ceramic transducers and the metal structures is drawn, based on the Mason equivalent circuit. The effect of mounting on the electrical response of piezoelectric transducers is studied experimentally. Using two identical transducer structures, power transmission of 0.33 mW through a 1 m long, 118 mm diameter cast iron pipe, with 8 mm wall thickness is demonstrated, at 1 V received voltage amplitude. A near-linear relationship between input and output voltage is observed. These results show that it is possible to deliver significant power to sensor nodes through acoustic waves in solid structures. The proposed method may enable the implementation of acoustic - powered wireless sensor nodes for structural and operation monitoring of pipeline infrastructure.
Kaur S, Halvorsen E, Sorasen O, et al., 2015, Characterization and Modeling of Nonlinearities in In-Plane Gap Closing Electrostatic Energy Harvester, JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, Vol: 24, Pages: 2071-2082, ISSN: 1057-7157
- Author Web Link
- Cite
- Citations: 11
Kiziroglou ME, Yeatman EM, 2015, Protection of Electronics from Environmental Temperature Spikes by Phase Change Materials, Journal of Electronic Materials, Vol: 44, Pages: 4589-4594, ISSN: 0361-5235
Protection of electronics from high-temperature environments is desirable inapplications such as harsh-environment industrial sensor networks for continuousmonitoring and probing. In this paper, the use of phase changematerial (PCM) encapsulation of electronics is proposed as protection fromenvironment-induced, probing-induced or electronic power burst-inducedtemperature spikes. An outline of the encapsulation method is given and aheat flow analysis is performed. A lumped element model is introduced and anumerical simulator is implemented. An encapsulation setup is fabricated andtested, allowing an experimental validation of the proposed method andmodel. The numerical simulation model is then used to study particulartemperature spike scenarios. The results demonstrate that at reasonableencapsulation sizes and for commercially available phase change and insulationmaterials, short-term protection from large temperature spikes can beprovided by the proposed method. As an indicative example, for a typicalsensor node normally operating at a 20C environment, PCM encapsulationmay provide protection for 28 s of exposure to 1000C per PCM gram.
Briand D, Yeatman E, Roundy S, 2015, Micro Energy Harvesting, ISBN: 9783527319022
With its inclusion of the fundamentals, systems and applications, this reference provides readers with the basics of micro energy conversion along with expert knowledge on system electronics and real-life microdevices. The authors address different aspects of energy harvesting at the micro scale with a focus on miniaturized and microfabricated devices. Along the way they provide an overview of the field by compiling knowledge on the design, materials development, device realization and aspects of system integration, covering emerging technologies, as well as applications in power management, energy storage, medicine and low-power system electronics. In addition, they survey the energy harvesting principles based on chemical, thermal, mechanical, as well as hybrid and nanotechnology approaches. In unparalleled detail this volume presents the complete picture -- and a peek into the future -- of micro-powered microsystems.
Boyle D, Kolcun R, Yeatman E, 2015, Devices in the internet of things, Journal of the Institute of Telecommunications Professionals, Vol: 9, Pages: 26-31, ISSN: 1755-9278
There are many potential applications in the utilities, critical infrastructure monitoring and control and environmental monitoring. This article charts the device-level technologies used in the creation the IoT, including hardware, software and communications. IoT's emergence coincided with the development of radio frequency identification (RFID) technology offering advantages such as the communicable range, ability to write data to a tag, and the possibility of reading multiple tags more efficiently with a single reader. RFID is now just one of many component IoT technologies. We have arrived at a situation where it is practically trivial to integrate computation and communication into any manufactured thing, and it is equally feasible to connect and technologically perceive natural things using communicable sensors. Furthermore, it is possible to react to, and control the environment using embedded computing devices coupled with actuators. Thorough comprehension of functional and non-functional requirements is necessary to develop an effective, efficient design specification for an IoT device. But given the large design space and complexity, there are numerous barriers to entry. As a result, many types of device have been adopted as practical de facto hardware development platforms across research communities, anc hacker and maker communities. In each case, intermediary 'operating systems', designed to simplify their programming by masking hardware complexity, are typically used. Their technical specifications are often not fully disclosed, but they do rely on well- defined standards to ensure the necessary interoperability. The majority of devices are characterised as single board computers. The final design for a market-ready product will likely be as efficient and cost-effective as possible in terms of design, but include sufficient redundancy to support software updates and potential shifts in standards. Since the early 2000s, the wireless sensor network comm
Jiang H, Kiziroglou ME, Yates DC, et al., 2015, A NON-HARMONIC MOTION-POWERED PIEZOELECTRIC FM WIRELESS SENSING SYSTEM, 18th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS), Publisher: IEEE, Pages: 710-713
- Author Web Link
- Cite
- Citations: 1
Kiziroglou ME, Elefsiniotis A, Kokorakis N, et al., 2015, Scaling of dynamic thermoelectric harvesting devices in the 1-100 cm<SUP>3</SUP> range, Conference on Smart Sensors, Actuators, and MEMS VII 1st SPIE Conference on Cyber-Physical Systems, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
Briand D, Yeatman E, Roundy S, 2015, Introduction to Micro Energy Harvesting, Publisher: WILEY-V C H VERLAG GMBH, ISBN: 978-3-527-31902-2
- Author Web Link
- Cite
- Citations: 62
Pillatsch P, Wright PK, Yeatman EM, et al., 2015, A Wireless Charging Mechanism For A Rotational Human Motion Energy Harvester, IEEE 12th International Conference on Wearable and Implantable Body Sensor Networks (BSN), Publisher: IEEE
Denisov A, Yeatman EM, 2014, Micromechanical Actuators Driven by Ultrasonic Power Transfer, JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, Vol: 23, Pages: 750-759, ISSN: 1057-7157
- Author Web Link
- Cite
- Citations: 9
Pillatsch P, Yeatman EM, Holmes AS, 2014, A piezoelectric frequency up-converting energy harvester with rotating proof mass for human body applications, Sensors and Actuators A: Physical, Vol: 206, Pages: 178-185, ISSN: 0924-4247
Energy harvesting from human motion faces the challenges of low frequency and random excitation. One strategy that has been successful in the past is frequency up-conversion. This paper introduces an inertial device that combines this principle, in the form of piezoelectric beam plucking through magnetic coupling with a rotating proof mass. The advantages rotational systems can have for body movements are discussed. The prototype is described and tested in a real world environment during a running race and later on in a laboratory environment on a custom built linear excitation table. Throughout these tests it is confirmed that such a device can operate over a broad range of frequencies and under varying orientations, making it suitable for this intended application. Across frequencies between 0.5 and 4 Hz and accelerations between 1 and 20 m/s2 power outputs in the range of tens of microwatts were achieved, with a peak value of 43 μW at 2 Hz and 20 m/s2 when the rotor went into a continuous rotation.
Pillatsch P, Yeatman EM, Holmes AS, 2014, Magnetic plucking of piezoelectric beams for frequency up-converting energy harvesters, SMART MATERIALS AND STRUCTURES, Vol: 23, ISSN: 0964-1726
- Author Web Link
- Cite
- Citations: 63
Kiziroglou ME, Wright SW, Toh TT, et al., 2014, Design and Fabrication of Heat Storage Thermoelectric Harvesting Devices, Industrial Electronics, IEEE Transactions on, Vol: 61, Pages: 302-309, ISSN: 0278-0046
Toh TT, Wright SW, Kiziroglou ME, et al., 2014, Inductive energy harvesting from variable frequency and amplitude aircraft power lines, ISSN: 1742-6596
Pillatsch P, Shashoua N, Holmes AS, et al., 2014, Degradation of Piezoelectric Materials for Energy Harvesting Applications, 14th International Conference on Micro- and Nano-Technology for Power Generation and Energy Conversion Applications (PowerMEMS), Publisher: IOP PUBLISHING LTD, ISSN: 1742-6588
- Author Web Link
- Cite
- Citations: 11
Jiang H, Kiziroglou ME, D C Yates, et al., 2014, A Motion-Powered Piezoelectric Pulse Generator for Wireless Sensing via FM Transmission, IEEE Internet of Things Journal, Vol: Under Review
Toh TT, Wright SW, Kiziroglou ME, et al., 2014, Inductive Energy Harvesting for Rotating Sensor Platforms, ISSN: 1742-6596
Jiang H, Kiziroglou ME, Yates DC, et al., 2014, A Piezoelectric Pulse Generator and FM Transmission Circuit for Self-Powered BSN Nodes, Wearable and Implantable Body Sensor Networks (BSN), 2014 11th International Conference on, Publisher: IEEE, Pages: 1-5
Yeatman E, Mitcheson P, 2014, Energy Harvesting and Power Delivery, Body Sensor Networks, Publisher: Springer London, Pages: 237-272, ISBN: 9781447163732
Toh TT, Wright SW, Kiziroglou ME, et al., 2014, A dual polarity, cold-starting interface circuit for heat storage energy harvesters, Sensors and Actuators A: Physical, Vol: 211, Pages: 38-44, ISSN: 0924-4247
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.