Characterization of a Low-Cost Millinewton Force Sensor for Ionic Polymer Metal Composite Actuators

Ionic polymer-metal composites (IPMCs) have become an area of interest in the past decade for their unique properties as actuators. Conventional IPMCs require the use of rare earth metals for electrodes making the fabrication of these materials expensive, time consuming to produce, and not suitable for large scale manufacturing. Due to the low actuational forces, in the millinewton scale, characterization of IPMCs is costly and often requires expensive force sensors and data acquisition (DAQ) systems. This thesis explores the capabilities of a low cost, two dimensional millinewton force sensor fabricated out of nitinol #1 wire and orthogonally mounted strain gauge pairs in half bridge configurations. An Arduino microcontroller based DAQ system and a modular test stand were developed to facilitate calibration of the force sensor and testing of IPMCs. The overall system cost, approximately $200 USD, was able to achieve a force resolution of 0.49 mN. Calibration of the force sensor was accomplished gravimetrically and the data was processed in an Arduino-LabVIEW™ interface. An ionic polymer-carbon composite (IPCC) fabrication concept was also developed that utilizes buckypaper (BP) electrodes, electrospun nanofibrous Nafion mats, and EMI-Tf ionic liquid for hydration. The IPCC concept has the potential to achieve faster actuation rates, larger deflections, and longer operations in air compared to IPMCs. The IPCC fabrication process developed takes a fraction of the time compared to conventional IPMC fabrication and can be applied to IPMC fabrication for production on an industrial scale

Mixed-source charger-supply CMOS IC

The proposed research objective is to develop, test, and evaluate a mixer and charger-supply CMOS IC that derives and mixes energy and power from mixed sources to accurately supply a miniaturized system. Since the energy-dense source stores more energy than the power-dense source while the latter supplies more power than the former, the proposed research aims to develop an IC that automatically selects how much and from which source to draw power to maximize lifetime per unit volume. Today, the state of the art lacks the intelligence and capability to select the most appropriate source from which to extract power to supply the time-varying needs of a small system. As such, the underlying objective and benefit of this research is to reduce the size of a complete electronic system so that wireless sensors and biomedical implants, for example, as a whole, perform well, operate for extended periods, and integrate into tiny spaces.Ph.D

Control Design for Micro Tubular Solid Oxide Fuel Cells, Demonstrating Lifetime and Performance Efficiency

Emerging techniques are being researched to introduce new environmentally friendly devices such as fuel cells to reshape the world into net zero carbon emissions. Currently there are different categories of fuel cells available, each category has its benefits, for this project a micro tubular solid oxide fuel cell (μSOFC) provided by the industrial partner Adelan Ltd. was used. The Adelan specific tubular design offers faster warm up, higher thermal flexibility and better sealing capabilities. However, Adelan Ltd wants a more robust control technique in the three core stages of the fuel cell which are start-up, warmup and shutdown. Cycling through these stages it is believed to damage the fuel cell significantly as thermal conditions inside the fuel cell core fluctuate the most. In this research a novel electronic control unit (ECU) is designed to improve efficiency and lifetime of the μSOFC. Furthermore, the controller is complying to the safety concerns arisen from using a high temperature device, for the product to be commercialised. The proposed controller KJ101 is designed using a four-layer PCB to reduce electrical noises and comply with CE (or UKCA for United Kingdom). This board was able to carry over the existing Adelan control technique and make further improvement and innovation. The controller is programmed in a low-level language (AVR-C using the GCC compiler) to ensure a critical oversight of the functionality while also being able to find and eliminate critical bugs early on. This method allows to have full control to the microcontroller’s functionalities and configuring them to the way that it is required for this project. A fuel cell is currently an expensive device and highly nonlinear device therefore a mathematical model was created to understand thermal responses of a fuel cell. The firmware for the ECU was calibrated and verified using an experimental μSOFC unit, this board showed that the system was able to have flexible smooth and well controlled start up and shut down processes. The proposed controller was able to improve operation by stabilizing the fuel cell at a target setpoint (such as 700°C) while also offering a flexible option of setpoints when being under operation. The temperature variation was another equivalent important topic that was improved by a proposed firmware technique. Finally, this controller was to offer multi-input multi-output control, where the fuel input was adjusted to reach the required power all while the temperature remained at a specific given setpoint by the manipulation of the cooling fans

Pem fuel cell modeling and converters design for a 48 v dc power bus

Fuel cells (FC) are electrochemical devices that directly convert the chemical energy of a fuel into electricity. Power systems based on proton exchange membrane fuel cell (PEMFC) technology have been the object of increasing attention in recent years as they appear very promising in both stationary and mobile applications due to their high efficiency, low operating temperature allowing fast startup, high power density, solid electrolyte, long cell and stack life, low corrosion, excellent dynamic response with respect to the other FCs, and nonpolluting emissions to the environment if the hydrogen is obtained from renewable sources. The output-voltage characteristic in a PEMFC is limited by the mechanical devices which are used for regulating the air flow in its cathode, the hydrogen flow in its anode, its inner temperature, and the humidity of the air supplied to it. Usually, the FC time constants are dominated by the fuel delivery system, in particular by the slow dynamics of the compressor responsible for supplying the oxygen. As a consequence, a fast load transient demand could cause a high voltage drop in a short time known as oxygen starvation phenomenon that is harmful for the FC. Thus, FCs are considered as a slow dynamic response equipment with respect to the load transient requirements. Therefore, batteries, ultracapacitors or other auxiliary power sources are needed to support the operation of the FC in order to ensure a fast response to any load power transient. The resulting systems, known as FC hybrid systems, can limit the slope of the current or the power generated by the FC with the use of current-controlled dc-dc converters. In this way, the reactant gas starvation phenomena can be avoided and the system can operate with higher efficiency. The purpose of this thesis is the design of a DC-DC converter suitable to interconnect all the different elements in a PEMFC-hybrid 48-V DC bus. Since the converter could be placed between elements with very different voltage levels, a buck-boost structure has been selected. Especially to fulfill the low ripple requirements of the PEMFCs, but also those of the auxiliary storage elements and loads, our structure has inductors in series at both its input and its output. Magnetically coupling these inductors and adding a damping network to its intermediate capacitor we have designed an easily controllable converter with second-order-buck-like dominant dynamics. This new proposed topology has high efficiency and wide bandwidth acting either as a voltage or as a current regulator. The magnetic coupling allows to control with similar performances the input or the output inductor currents. This characteristic is very useful because the designed current-controlled converter is able to withstand shortcircuits at its output and, when connected to the FC, it facilitates to regulate the current extracted from the FC to avoid the oxygen starvation phenomenon. Testing in a safe way the converter connected to the FC required to build an FC simulator that was subsequently improved by developing an emulator that offered real-time processing and oxygen-starvation indication. To study the developed converters and emulators with different brands of PEMFCs it was necessary to reactivate long-time inactive Palcan FCs. Since the results provided by the manual reactivation procedure were unsatisfactory, an automatic reactivation system has been developed as a complementary study of the thesis.En esta tesis se avanzo en el diseño de un bus DC de 48 V que utiliza como elemento principal de generación de energía eléctrica una pila de combustible. Debido a que la dinámica de las pilas de combustible están limitadas por sus elementos mecánicos auxiliares de control una variación rápida de una carga conectada a ella puede ocasionar daños. Es por esto que es necesario utilizar elementos almacenadores de energía que puedan suministrar estas rápidas variaciones de carga y convertidores para que gestionen de una forma controlada la potencia del bus DC. Durante la realización de pruebas de los convertidores es de gran importancia utilizar emuladores o simuladores de pilas de combustibles, esto nos permite de una forma económica y segura realizar pruebas criticas antes de conectar los convertidores a la pila. Adicionalmente una nueva topologia de convertidor fue presentada y ésta gestionará la potencia en el bu

Hybrid Electric Fuel Cell for Portable Electronics

Final report and team photo for Project 26 of ME450, Winter 2009 semester.Harris Corporation is interested in developing a hybrid fuel cell-battery system using a Direct Methanol Fuel Cell to power a cellular phone. Our task is to develop such a system and resolve the packaging issues regarding heat management and structural durability to ensure the product’s safety. This will involve characterizing the power needs of a specific cell phone and creating a hybrid system using off-the-shelf components in combination with custom circuitry and packaging.Patrick Pendell (Harris Corp.); Mentors: Jerry Betteridge, Michael Sternowski, Ron Jonas (Harris Corp.)http://deepblue.lib.umich.edu/bitstream/2027.42/62478/2/ME450 Winter2009 Team Photo - Project 26 - Hybrid Portable Power Cell.jpghttp://deepblue.lib.umich.edu/bitstream/2027.42/62478/1/ME450 Winter2009 Final Report - Project 26 - Hybrid Portable Power Cell.pd

Integrated By Design: An Investigation into Solid-State Battery Processing & the Elucidation of Reaction Mechanisms

Among the portable electronics market, Li-ion batteries remain the preferred choice for many applications, due to their high specific energy. However, current battery technologies have flaws associated with both their chemistries, manufacturing methods and architecture. Battery and device architectures are regularly kept as separate entities during product design, and only put together in the final design, unnecessarily increasing device footprint, costs and weight. Herein, we explore an alternative approach to these limitations, by developing an integrated battery antenna system. The three main components of the battery: the cathode, the electrolyte and the anode are investigated with an aim to design an all-solid-state flexible, wearable, body conformable antenna battery system. Li2FeSiO4 is explored as a high capacity, environmentally benign cathode material. Utilizing in-operando XAS and ex-situ XRS to explore the origin of the materials' additional capacity associated with the removal of >1Li+ per unit formula. It is found that oxygen contributes, reversibly, as a charge compensation mechanism to the additional capacity. A PEGDA based solid polymer electrolyte membrane (PEM) is explored as a high performance, high conductivity, flexible, stretchable and thermally stable alternative to liquid electrolytes. The PEM is found to be stable up to 4.7V vs Li/Li+ and yield a conductivity of 1.4x10-3Scm-1, which places it securely into the "superionic" region. For the first time, this system has been applied to a full-cell configuration, yielding strong cycling performance throughout, with full-cell capacities reaching as high as 151mAhg-1at room temperature. PEDOT:PSS is a mixed conductive polymer, assessed as a potential anode material. The material was deposited using three different techniques:(I) tape casting (II) spray-coating (III) inkjet printing. It was found that cycling performance was heavily dependent on the manufacturing technique employed. Inkjet printed, binder free films exhibited the greatest performance with capacities stable across all 50 cycles tested. Finally, the PEDOT:PSS anode was incorporated into an on-body electronic device - an RFID antenna, utilizing the antenna architecture as a dual purpose component. The antenna powered by the integrated battery exhibited strong performance characteristics, matching those of a commercial coin cell battery

Theoretical Analysis of a Potentiostat for Studying Microbial Fuel Cells

For many years, Microbial Fuel Cells (MFCs) have been developed as alternatives for generating electricity via the oxidation of organic matter by bacteria. Even though individual MFC units are low in power, significant progress has been achieved in terms of MFC material and configurations, enabling them to generate higher output levels. Nonetheless, MFCs are are mainly produced using conventional laboratory methods that can take up to several months to bring the MFCs to their maximum power aptitudes. In this dissertation, an approach to use a low-cost potentiostat was developed in order to study MFCs comportament. Initially, the work focused on establishing an interface on Node-RED and an interconnection between the living cells in the MFC. In order to achieve that, was used a mbed NXP LPC1768 microcontroller to communicate with the interface created and also with the potentiostat. To fully explore the potentiostat, were studied several electrochemical tests possible to execute in the MFC reactor and the expected results. Finally, is possible to say that the potentiostat is fast, produces low noise and is a versatile instrument, very promising in the study of this emerging renewable energy like is MFCs.Há vários anos, que as Células de Combustível Microbianas têm sido desenvolvidas como alternativas para gerar eletricidade através da oxidação da matéria orgânica por bactérias. Embora as unidades individuais destas células tenham um baixo consumo de energia, tem-se alcançado um progresso significativo em termos de materiais e configurações das células, permitindo-lhes gerar níveis de produção mais elevados. No entanto, estas células são produzidas principalmente através de métodos de laboratório convencionais que podem levar vários meses até que as células alcancem as suas aptidões de potência máxima. Nesta dissertação, uma abordagem para o uso de um potencióstato de baixo custo foi desenvolvida para estudar o comportamento das células de combustível microbianas. Inicialmente, o trabalho concentrou-se em estabelecer uma interface no Node-RED e fazer a ligação entre as células vivas dos reatores. Para tal, foi utilizado o microcontrolador mbed NXP LPC1768 para comunicar com a interface criada e também com o potencióstato. De forma a explorar totalmente o potencióstato, estudamos vários testes eletroquímicos possíveis de executar no reator das células de combustível microbianas e os resultados esperados. Por fim, pode-se dizer que o potencióstato é rápido, produz baixo ruído e é um instrumento versátil, muito promissor no estudo desta energia renovável emergente como são as células de combustível microbianas

Power Management Circuits for Energy Harvesting Applications

Energy harvesting is the process of converting ambient available energy into usable electrical energy. Multiple types of sources are can be used to harness environmental energy: solar cells, kinetic transducers, thermal energy, and electromagnetic waves. This dissertation proposal focuses on the design of high efficiency, ultra-low power, power management units for DC energy harvesting sources. New architectures and design techniques are introduced to achieve high efficiency and performance while achieving maximum power extraction from the sources. The first part of the dissertation focuses on the application of inductive switching regulators and their use in energy harvesting applications. The second implements capacitive switching regulators to minimize the use of external components and present a minimal footprint solution for energy harvesting power management. Analysis and theoretical background for all switching regulators and linear regulators are described in detail. Both solutions demonstrate how low power, high efficiency design allows for a self-sustaining, operational device which can tackle the two main concerns for energy harvesting: maximum power extraction and voltage regulation. Furthermore, a practical demonstration with an Internet of Things type node is tested and positive results shown by a fully powered device from harvested energy. All systems were designed, implemented and tested to demonstrate proof-of-concept prototypes

Energy Management

Forecasts point to a huge increase in energy demand over the next 25 years, with a direct and immediate impact on the exhaustion of fossil fuels, the increase in pollution levels and the global warming that will have significant consequences for all sectors of society. Irrespective of the likelihood of these predictions or what researchers in different scientific disciplines may believe or publicly say about how critical the energy situation may be on a world level, it is without doubt one of the great debates that has stirred up public interest in modern times. We should probably already be thinking about the design of a worldwide strategic plan for energy management across the planet. It would include measures to raise awareness, educate the different actors involved, develop policies, provide resources, prioritise actions and establish contingency plans. This process is complex and depends on political, social, economic and technological factors that are hard to take into account simultaneously. Then, before such a plan is formulated, studies such as those described in this book can serve to illustrate what Information and Communication Technologies have to offer in this sphere and, with luck, to create a reference to encourage investigators in the pursuit of new and better solutions