Atualmente há grande investimento por parte das empresas em sistemas que não podem parar e, conseqüentemente, em sistemas de gerenciamento para perceber a ocorrência de falhas ou prevê-las e evitar que elas aconteçam. Para amenizar os efeitos de falhas no fornecimento de energia elétrica, que são ainda comuns no país e em boa parte do mundo, são utilizados os no-breaks. Esses equipamentos são projetados para garantir o fornecimento de energia por um tempo definido e limitado nos momentos em que a concessionária de energia elétrica interrompe esse fornecimento. O objetivo principal do presente trabalho é investigar uma solução de gerenciamento de no-breaks que possui como grande diferencial a utilização do paradigma de gerenciamento distribuído por delegação, com o uso do protocolo SNMP, apresentando as vantagens desse paradigma. Para a distribuição de tarefas, a solução utiliza a MIB Script e uma implementação deste padrão (JASMIN – Java Script MIB Implementation) de forma que toda a interatividade com a ferramenta e a automatização dos processos que compõem a solução foi implementada com o uso das ferramentas livres Apache e PHP. O trabalho apresenta uma breve descrição sobre o funcionamento dos no-breaks e destaca a UPS-MIB, MIB padrão para gerenciamento desses equipamentos, além de objetos importantes disponibilizados em outras MIBs proprietárias utilizadas para o gerenciamento de no-breaks. Além disso, o presente estudo sugere o uso de ferramentas para que o sistema de gerência seja responsável pelas estações alimentadas pelos nobreaks, ou seja, quando identificado que está próximo o momento do no-break não conseguir mais alimentar a carga, deve-se desligar a carga com segurança para que não ocorra uma perda de dados maior nem haja danos em componentes. Nota-se que o gerenciamento utilizado neste trabalho, realizado através da ferramenta desenvolvida, facilita a detecção de falhas no sistema de fornecimento de energia, de modo a interagir satisfatoriamente com no-breaks para verificar condições da rede elétrica e tomar decisões pró-ativas com o intuito de manter uma rede de computadores em funcionamento, sem que haja percalços por problemas de falta de energia. / Nowadays most companies are investing in non-stop systems, which leads to investments in management systems to know when a fault occurs or to foresee and avoid them. To reduce the effects of power supply faults (which are common in Brazil and in other parts of the world), people use UPS systems. These equipments are designed to guarantee the power supply for a pre-defined limited time, just in case the power company interrupts the supply. The main goal of this work is to present the implementation of a management application for UPS systems, which has the differential of using the management-bydelegation paradigm, based on SNMP, showing the advantages of this paradigm. The application uses Script MIB and an implementation of this standard (JASMIN - Java Script MIB Implementation) for task distribution, in such a way that all the tool interactivity and process automation was done using the free tools Apache and PHP. The work also presents a brief description about the UPS functioning, and shows UPS-MIB, the standard MIB for UPS management. Additionally the work presents some important objects available in some custom MIBs that are used for UPS management too. This study suggests the use of a set of tools to make the management system responsible for the workstations plugged on the UPS, which means that when the UPS is about to be unable to maintain the load, it should be turned off safely to avoid data losses or hardware faults. One can note that the management done in this work through the developed tool makes easy the fault detection in the power supply system. This leads to a good interaction with the UPS to verify the conditions of the power network in order to take decisions to maintain the computer network running safely.

Wireless Sensor Networks (WSNs), in addition to enabling monitoring solutions for numerous new applications areas, have gained huge popularity as a cost-effective, dynamically scalable, easy to deploy and maintainable alternatives to conventional infrastructure-based monitoring solutions. A WSN consists of spatially distributed autonomous wireless sensor nodes that measure desired physical phenomena and operate in a collaborative manner to relay the acquired information wirelessly to a central location. A wireless sensor node, integrating the required resources to enable infrastructure-less distributed monitoring, is constrained by its size, cost and energy. In order to address these constraints, a typical wireless sensor node is designed based on low-power and low-cost modules that in turn provide limited communication and processing performances. Data and computation intensive wireless monitoring applications, on the other hand, not only demand higher communication bandwidth and computational performance but also require practically feasible operational lifetimes so as to reduce the maintenance cost associated with the replacement of batteries. In relation to the communication and processing requirements of such applications and the constraints associated with a typical wireless sensor node, this thesis explores energy efficient wireless sensor node architecture that enables realization of data and computation intensive applications. Architectures enabling raw data transmission and in-sensor processing with various technological alternatives are explored. The potential architectural alternatives are evaluated both analytically and quantitatively with regards to different design parameters, in particular, the performance and the energy consumption. For quantitative evaluation purposes, the experiments are conducted on vibration and image-based industrial condition monitoring applications that are not only data and computation intensive but also are of practical importance. Regarding the choice of an appropriate wireless technology in an architecture enabling raw data transmission, standard based communication technologies including infrared, mobile broadband, WiMax, LAN, Bluetooth, and ZigBee are investigated. With regards to in-sensor processing, different architectures comprising of sequential processors and FPGAs are realized to evaluate different design parameters, especially the performance and energy efficiency. Afterwards, the architectures enabling raw data transmission only and those involving in-sensor processing are evaluated so as to find an energy efficient solution. The results of this investigation show that in-sensor processing architecture, comprising of an FPGA for computation purposes, is more energy efficient when compared with other alternatives in relation to the data and computation intensive applications. Based on the results obtained and the experiences learned in the architectural evaluation study, an FPGA-based high-performance wireless sensor platform, the SENTIOF, is designed and developed. In addition to performance, the SETNIOF is designed to enable dynamic optimization of energy consumption. This includes enabling integrated modules to be completely switched-off and providing a fast configuration support to the FPGA.  In order to validate the results of the evaluation studies, and to assess the performance and energy consumption of real implementations, both the vibration and image-based industrial monitoring applications are realized using the SENTIOF. In terms of computational performance for both of these applications, the real-time processing goals are achieved. For example, in the case of vibration-based monitoring, real-time processing performance for tri-axes (horizontal, vertical and axial) vibration data are achieved for sampling rates of more than 100 kHz. With regards to energy consumption, based on the measured power consumption that also includes the power consumed during the FPGA’s configuration process, the operational lifetimes are estimated using a single cell battery (similar to an AA battery in terms of shape and size) with a typical capacity of 2600 mA. In the case of vibration-based condition monitoring, an operational lifetime of more than two years can be achieved for duty-cycle interval of 10 minutes or more. The achievable operational lifetime of image-based monitoring is more than 3 years for a duty-cycle interval of 5 minutes or more.

This assignment was given by Nordic Semiconductor. In this project a radio frequency energy harvesting system able to harvest ambient power at 900 MHz (GSM) was simulated and designed. A Villard voltage multiplier, boost converter and power management circuit was implemented for the harvesting system. The intention was to implement a system which would give sufficient output power and voltage to supply a load (nRF52810) at all times. The nRF52810 is a power efficient multi protocol SoC made by Nordic Semiconductor. Since the power harvested by the antenna is of AC power, a recti er was needed. A Villard voltage multiplier was proposed as the most suitable application. It not only recti es the voltage, but the voltage doubles for every stage. A 2-stage Villard voltage multiplier was proposed with the advantage that in theory the output voltage should be four times higher in magnitude than the input voltage. There exists several other ways to boost a voltage, a voltage boost converter was combined with the Villard Voltage multiplier. According to calculations the boost converter should boost the voltage up to 2.3 V. Since the assumed power from the harvesting system may be lower than the power consumed by the load, a power managing circuit was also needed, which would avoid the load to drain the current from the storage element before the voltage level was sufficient. Different solutions for a power management circuit was proposed using different variations of MOSFETs. A real-life design was implemented, but the Villard voltage multiplier gave out a much lower e efficiency than expected from simulations. The output power of the VVM was too low to supply the load (nRF52810).

Fuel cell technology has reached commercialisation of fuel cells in application areas such as residential power systems, automobile engines and driving of industrial manufacturing processes. This thesis gives an overview of the current state of fuel cell-based technology research and development, introduces a μCHP system sizing strategy and proposes methods of improving on the implementation of residential fuel cell-based μCHP technology. The three methods of controlling residential μCHP systems discussed in this thesis project are heat-led, electricity-led and cost-minimizing control. Simulations of a typical HT PEMFC -based residential μCHP unit are conducted using these control strategies. A model of a residential μCHP system is formulated upon which these simulated tests are conducted. From these simulations, equations to model the costs of running a fuel-cell based μCHP system are proposed. Having developed equations to quantify the running costs of the proposed μCHP system a method for determining the ideal size of a μCHP system is developed. A sizing technique based on industrial CHP sizing practices is developed in which the running costs and capital costs of the residential μCHP system are utilised to determine the optimal size of the system. Residential thermal and electrical load profile data of a typical Danish household are used. Having simulated the system a practical implementation of the power electronics interface between the fuel cell and household grid is done. Two topologies are proposed for the power electronics interface a three-stage topology and a two-stage topology. The efficiencies of the overall systems of both topologies are determined. The system is connected to the grid so the output of each system is phase-shifted and DC injection, harmonic distortion, voltage range and frequency range are determined for both systems to determine compliance with grid standards. Deviations between simulated results and experimental results are recorded and discussed and relevant conclusions are drawn from these.

This master thesis describes the design of a DC/DC converter for one photovoltaic panel with a 250 W peak power. The master thesis is divided into parts dealing with detailed design of power electronics, analog circuit design, description of control MPPT algorithms and software for control circuit. The chapter with the mathematical modeling of the converter created in the Matlab Simulink was added beyond the assignment.

The thesis focuses on the power management support of battery systems in charging mode and charging systems for electric vehicles in the LV network. The thesis includes an overview of the distribution network of the Czech Republic, means of voltage regulation and the existing legislative framework for the connection of charging systems. The thesis describes the methods of active and reactive power control depending on the voltage and frequency. The practical part focuses on the simulation of grid support at different penetration levels of BESS and EVC in MATLAB Simulink and the verification of the support function on a laboratory system. In the last part, the methods of implementing the control system for BESS and EVC operating in the LV grid are specified.

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Satellite power management systems play a crucial role in ensuring the operational success andlongevity of satellite missions. As satellites operate in the harsh environment of space, efficient powermanagement is essential to maximize energy utilization, maintain stability, and extend mission lifespans.Within the framework of the Avionics department, CNES has acquired the Power Conditioning andDistribution Unit (PCDU) GOMSPACE P60, in order to demonstrate the reliability of Commercial Offthe Shelf (COTS) products and viability of a low-cost satellite architecture. In this thesis, the integrationand characterization of the GOMSPACE P60 PCDU is presented. This internship consisted of mainlythree objectives. The development of the software needed to control the equipment, the development ofa graphics unit interface (GUI) for housekeeping data visualisation and the preparation, carrying out andreporting of different performance tests. Some of the main characteristics of the system assessed, includethe high adaptability that it has based on the mission requirements. The equipment appeared to notprovide easy access to the design after delivery, but it functions nominally upon delivery. It is robust inlow or high temperatures as well as in harsh (electromagnetic interference) EMI perturbations. Thiselectrical power system (EPS) allows for high control of its board parameters and observability of thetelemetry data. However, this command control is hard to integrate based on the supplied C libraries andthere were occasional unexpected behaviours from the system. Based on the assessment done duringthis internship, it could replace previously used PCDUs that have lesser performance and higher cost infuture nanosatellites low cost missions such as student or proof of concept missions. However, thelimited information and details provided in the data package by the distributor, makes the equipmentinsufficient for larger missions. Higher level of analysis and qualification is required for this scope,based on the common requirements and standards followed by the agency.

Distributed generators (DGs) with integration of renewable resources (RRs) such as photovoltaic (PV) and wind turbine have been widely considered to reduce the dependency on conventional power generation systems along with enhancement of the quality and sustainability of the power system. Recently, DC microgrid has gained popularity in many real-world applications such as rural electrification due to its simplicity and low power losses. However, the power variability of renewable resources and continuous change in load demand imposes risks of power mismatch in standalone DC systems that increase the chances of stability and reliability issues. Therefore, complementary generation and/or storage systems are coupled with standalone DC microgrid to mitigate the power fluctuations and maintain a power balance in the system. This dissertation presents a power management strategy (PMS) based on model predictive control (MPC) for a standalone DC microgrid. A control scheme for a standalone DC microgrid system with RRs, storage, and load is desired to have the capability of effective power management that maximizes the extraction of energy from renewable generators, minimizes the transients in the system during disturbances, and protects the storage from over/under charging conditions. As a part of the proposed MPC, an optimization problem is formulated to meet the voltage performance in the system with respect to operating conditions and constraints. The proposed PMS uses the ARIMA prediction method to forecast the load and environmental parameters. The predicted parameters are utilized to estimate the future performance of the system by solving the dynamic model of the system, and a cost function is optimized to generate suitable control sequences. This research also presents detailed mathematical models of the considered systems. This dissertation presents an extensive simulation-based analysis of the proposed approach. With the proposed control, maximum utilization of the renewable generators has been achieved, and the DC bus voltage is regulated at nominal value with minimum transients under various load/environmental disturbances. Moreover, the research investigates the proposed MPC based on ARIMA prediction by comparing the performance of different types of prediction methods. The dissertation also measures the effectiveness of the proposed MPC by comparing its performance with a conventional PI controller.