Monitoração de tensão em equipamentos alimentados por bateria

Neste projeto é implementado um sistema de monitoração da tensão de bateria de equipamentos alimentados por essa fonte de energia. O objetivo principal deste projeto é disponibilizar uma leitura de fácil entendimento das condições da bateria, disponibilizado as informações em um display LCD. Desta forma, a verificação desta fonte de energia pode ser realizada em qualquer instante, sendo possível antever imprevistos. Para isto, é utilizado um microcontrolador PIC 16F876, programado em linguagem C e Assembler. A aplicação dos sinais é controlada pelo microntrolador. O microcontrolador monitora as informações da fonte de alimentação utilizada, medindo sua corrente, tensão e a quantidade de carga existente na fonte no momento exato da conexão ao dispositivo pelo usuário.Neste projeto é implementado um sistema de monitoração da tensão de bateria de equipamentos alimentados por essa fonte de energia. O objetivo principal deste projeto é disponibilizar uma leitura de fácil entendimento das condições da bateria, disponibilizado as informações em um display LCD. Desta forma, a verificação desta fonte de energia pode ser realizada em qualquer instante, sendo possível antever imprevistos. Para isto, é utilizado um microcontrolador PIC 16F876, programado em linguagem C e Assembler. A aplicação dos sinais é controlada pelo microntrolador. O microcontrolador monitora as informações da fonte de alimentação utilizada, medindo sua corrente, tensão e a quantidade de carga existente na fonte no momento exato da conexão ao dispositivo pelo usuário

Design and Performance Evaluation of a Battery Simulator

The increasing demand on alternative fuel vehicles, especially electric vehicles (EVs), has created an enormous market, as well as great opportunities for further improvements, for battery industry. However, using battery packs as the energy source in the design/development process of new electric vehicles, is not an optimal choice, due to high cost and cycle life reduction of battery cells. Utilizing a battery simulator, with bidirectional power transactions with the grid, which can emulate different battery cell chemistries and battery pack sizes, is a viable solution to the problem. In this work, a battery simulator is proposed which has the potential of providing a high power DC supply, while emulating multiple types of battery cell chemistries, including Li-ion, lead-acid, NiCd, NiMH, and polymer-lithium. The proposed battery simulator consists of two main parts. The first part is the battery model that generates the reference signal for the DC terminal voltage of the battery simulator according to the present value of the load current. The second part is a voltage-source converter (VSC) that controls its DC-side voltage according to the reference signal provided by the battery model. Different battery modelling approaches are introduced and compared to select the most appropriate model to be realized. The control strategy and controller tuning method are also discussed following a systematic approach. Simulations under various loading conditions are carried out and extended simulation results are presented to verify the expected capabilities of the proposed battery simulator

Application priority framework for fixed mobile converged communication networks

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The current prospects in wired and wireless access networks, it is becoming increasingly important to address potential convergence in order to offer integrated broadband services. These systems will need to offer higher data transmission capacities and long battery life, which is the catalyst for an everincreasing variety of air interface technologies targeting local area to wide area connectivity. Current integrated industrial networks do not offer application aware context delivery and enhanced services for optimised networks. Application aware services provide value-added functionality to business applications by capturing, integrating, and consolidating intelligence about users and their endpoint devices from various points in the network. This thesis mainly intends to resolve the issues related to ubiquitous application aware service, fair allocation of radio access, reduced energy consumption and improved capacity. A technique that measures and evaluates the data rate demand to reduce application response time and queuing delay for multi radio interfaces is proposed. The technique overcomes the challenges of network integration, requiring no user intervention, saving battery life and selecting the radio access connection for the application requested by the end user. This study is split in two parts. The first contribution identifies some constraints of the services towards the application layer in terms of e.g. data rate and signal strength. The objectives are achieved by application controlled handover (ACH) mechanism in order to maintain acceptable data rate for real-time application services. It also looks into the impact of the radio link on the application and identifies elements and parameters like wireless link quality and handover that will influence the application type. It also identifies some enhanced traditional mechanisms such as distance controlled multihop and mesh topology required in order to support energy efficient multimedia applications. The second contribution unfolds an intelligent application priority assignment mechanism (IAPAM) for medical applications using wireless sensor networks. IAPAM proposes and evaluates a technique based on prioritising multiple virtual queues for the critical nature of medical data to improve instant transmission. Various mobility patterns (directed, controlled and random waypoint) has been investigated and compared by simulating IAPAM enabled mobile BWSN. The following topics have been studied, modelled, simulated and discussed in this thesis: 1. Application Controlled Handover (ACH) for multi radios over fibre 2. Power Controlled Scheme for mesh multi radios over fibre using ACH 3. IAPAM for Biomedical Wireless Sensor Networks (BWSN) and impact of mobility over IAPAM enabled BWSN. Extensive simulation studies are performed to analyze and to evaluate the proposed techniques. Simulation results demonstrate significant improvements in multi radios over fibre performance in terms of application response delay and power consumption by upto 75% and 15 % respectively, reduction in traffic loss by upto 53% and reduction in delay for real time application by more than 25% in some cases

Model-based prognostics for energy-constrained mobile systems operating in stochastic environments

Due to development of novel and more efficient energy storage systems we bear witness to the dawn of a new era of mobile systems. They have become sophisticated in terms of hardware components and software applications which have made it possible to develop integrated solutions for a large number of imaginable applications ranging from electric vehicles all the way to fully autonomous systems operating in a wide variety of ecosystems, e.g., service, surveillance or bio-inspired robots. Generally it is expected that a mobile system exhibits a sufficient degree of autonomy in the sense of energy availability such that it at least accomplishes the mission objectives for which it is intended. Nevertheless, such autonomy, is influenced to a large extent by the remaining energy that can be retrieved from its energy storage system and by the environment conditions in which the system operates. Assessing the reliability of a mission requires using systems internal and external situational awareness to determine if the available energy at least meets the energy needs demanded by the future operation of the mobile system in order to determine its remaining useful life (RUL). Having this information as soon as possible may allow the decision maker to apply a contingency plan to intervene and reconfigure the mission execution strategy in order to improve the probability of success, in those situations in which the system becomes incapable of achieving the original mission objectives. Numerous studies have been published for assessing mission reliability and estimating the RUL of mobile systems. However, they deal with structured environment conditions and thus with relatively deterministic loads. Moreover, these approaches neglect the inherent uncertainty which stems from multiple sources such as the lack of knowledge about the true energy available in the mobile system, the noise introduced by sensors or the randomness of the operation environment, just to mention a few. The approach presented in this work is built around the belief that the RUL estimation is formulated as an uncertainty propagation problem. Accordingly, to estimate the RUL multiple sources of uncertainty involved in its estimation are first characterized and then propagated with the aim of computing their combined effect, expressed in terms of a probability density function. The approach developed here achieves this estimation in a Monte-Carlo fashion in which several RUL realizations are simulated in order to accurately estimate its entire probability distribution. The aim of this work is therefore devoted to develop a solution capable of estimating the RUL with application to energy-constrained mobile systems operating in stochastic environments

Discharge Current Steering for Battery Lifetime Optimization

Recent work on battery-driven power management has demonstrated that sequential discharge is suboptimal in multi-battery systems, and lifetime can be maximized by distributing (steering) the current load on the available batteries, thereby discharging them in a partially concurrent fashion. Based on these observations, we formulate multi-battery lifetime maximization as a continuous, constrained optimization problem, which can be efficiently solved by non-linear optimizers. We show that great lifetime extensions can be obtained with respect to standard sequential discharge, as well to previously proposed battery allocation schemes