Universidade Federal do Cearà / Este trabalho apresenta a concepÃÃo, projeto e implementaÃÃo de um conversor CC/CC elevador para interligar um painel fotovoltaico a um banco de ultracapacitores para armazenamento de energia em substituiÃÃo Ãs baterias automotivas convencionais. Na saÃda dos ultracapacitores utiliza-se um conversor CC/CC abaixador, que fornece essa energia a um sistema de telecomunicaÃÃo para suprimento de um transceptor monocanal visando ao atendimento do serviÃo de telefonia rural/Internet em comunidades isoladas da rede pÃblica de energia. O sistema pode suprir o serviÃo de comunicaÃÃo para uma comunidade isolada da rede de energia elÃtrica por atà trÃs horas no perÃodo noturno, quando utilizado um equipamento rÃdio com cabos, conectores e antena para transmissÃo e recepÃÃo de sinal de telefonia com potÃncia de consumo de 13 W e com radiaÃÃo solar mÃdia de 5.500 W/m2/dia. Durante o dia, a energia solar à capturada por um painel fotovoltaico e armazenada em ultracapacitores atravÃs de um conversor boost. Este conversor possibilita a carga dos ultracapacitores no ponto de mÃxima potÃncia (MPP) do painel fotovoltaico. O transceptor à ativado quando se tira o fone do gancho e a alimentaÃÃo do sistema vem do painel via ultracapacitores. Caso haja ligaÃÃes durante o dia, o painel fotovoltaico supre as necessidades do equipamento transceptor. à noite, o painel utilizado nÃo gera energia suficiente para alimentar o sistema de telecomunicaÃÃo. No perÃodo noturno, caso ocorra uma chamada telefÃnica para o sistema proposto, o transceptor serà acionado, o assinante deverà retirar o monofone do gancho do aparelho telefÃnico para realizar o atendimento. Durante essa operaÃÃo o transceptor consome aproximadamente 13 W de potÃncia, que à fornecida pelos ultracapacitores, os quais estÃo interligados atravÃs do conversor buck. O sistema proposto à controlado por um microcontrolador e um circuito de controle, que procura o ponto de mÃxima potÃncia (MPP) do painel fotovoltaico, monitora o nÃvel da tensÃo dos ultracapacitores e determina o tempo de funcionamento do conversor CC/CC, que possibilita o fornecimento de energia para o transceptor pelos ultracapacitores. / This work presents the conception, design and implementation of a DC/DC boost converter to connect a photovoltaic panel to a bank of ultracapacitors for energy storage to replace the conventional automotive batteries. In the output of ultracapacitors a DC/DC step-down converter is used. This converter provides power to a telecommunication system for the supply of a single channel transceiver with the purpose of providing the services of rural telephony and Internet in isolated communities from the public energy grid. The system can provide the communication service to a isolated community from the power grid for up to three hours at night when used with radio equipment with cables, connectors and antenna for transmitting and receiving phone signal with consumption power of 13 W and with solar radiation rate of 5.500 W/m2/day. During the day solar energy is captured by a photovoltaic panel and stored in ultracapacitors through a boost converter. This converter enables ultracapacitors to charge at the maximum power point (MPP) of the photovoltaic panel. The transceiver is activated when the phone is taken off the hook and the system power comes from the panel via ultracapacitors. If there are calls during the day, the photovoltaic panel meets the needs of the transceiver. At night, the panel used does not generate enough energy to power the telecommunication system. At night, if there is a phone call to the proposed system, the transceiver will be triggered, and the subscriber should take the handset off the hook to answer an incoming call. During this operation, the transceiver consumes approximately 13 W of power, which is provided by ultracapacitors that are interconnected through the buck converter. The proposed system is controlled by a microcontroller and a control circuit which tracks the maximum power point (MPP) of the photovoltaic panel, monitors the voltage level of ultracapacitors and determines the operating time of the DC/DC converter which enables the provision of power to the transceiver by the ultracapacitors.This work presents the conception, design and implementation of a DC/DC boost converter to connect a photovoltaic panel to a bank of ultracapacitors for energy storage to replace the conventional automotive batteries. In the output of ultracapacitors a DC/DC step-down converter is used. This converter provides power to a telecommunication system for the supply of a single channel transceiver with the purpose of providing the services of rural telephony and Internet in isolated communities from the public energy grid. The system can provide the communication service to a isolated community from the power grid for up to three hours at night when used with radio equipment with cables, connectors and antenna for transmitting and receiving phone signal with consumption power of 13 W and with solar radiation rate of 5.500 W/m2/day. During the day solar energy is captured by a photovoltaic panel and stored in ultracapacitors through a boost converter. This converter enables ultracapacitors to charge at the maximum power point (MPP) of the photovoltaic panel. The transceiver is activated when the phone is taken off the hook and the system power comes from the panel via ultracapacitors. If there are calls during the day, the photovoltaic panel meets the needs of the transceiver. At night, the panel used does not generate enough energy to power the telecommunication system. At night, if there is a phone call to the proposed system, the transceiver will be triggered, and the subscriber should take the handset off the hook to answer an incoming call. During this operation, the transceiver consumes approximately 13 W of power, which is provided by ultracapacitors that are interconnected through the buck converter. The proposed system is controlled by a microcontroller and a control circuit which tracks the maximum power point (MPP) of the photovoltaic panel, monitors the voltage level of ultracapacitors and determines the operating time of the DC/DC converter which enables the provision of power to the transceiver by the ultracapacitors.This work presents the conception, design and implementation of a DC/DC boost converter to connect a photovoltaic panel to a bank of ultracapacitors for energy storage to replace the conventional automotive batteries. In the output of ultracapacitors a DC/DC step-down converter is used. This converter provides power to a telecommunication system for the supply of a single channel transceiver with the purpose of providing the services of rural telephony and Internet in isolated communities from the public energy grid. The system can provide the communication service to a isolated community from the power grid for up to three hours at night when used with radio equipment with cables, connectors and antenna for transmitting and receiving phone signal with consumption power of 13 W and with solar radiation rate of 5.500 W/m2/day. During the day solar energy is captured by a photovoltaic panel and stored in ultracapacitors through a boost converter. This converter enables ultracapacitors to charge at the maximum power point (MPP) of the photovoltaic panel. The transceiver is activated when the phone is taken off the hook and the system power comes from the panel via ultracapacitors. If there are calls during the day, the photovoltaic panel meets the needs of the transceiver. At night, the panel used does not generate enough energy to power the telecommunication system. At night, if there is a phone call to the proposed system, the transceiver will be triggered, and the subscriber should take the handset off the hook to answer an incoming call. During this operation, the transceiver consumes approximately 13 W of power, which is provided by ultracapacitors that are interconnected through the buck converter. The proposed system is controlled by a microcontroller and a control circuit which tracks the maximum power point (MPP) of the photovoltaic panel, monitors the voltage level of ultracapacitors and determines the operating time of the DC/DC converter which enables the provision of power to the transceiver by the ultracapacitors.

Rural telephony has historically been a recurring subject of concern for most large developing countries. It is generally considered that rural telephone users do not generate the same level of telephone traffic and, thus, revenue as urban users, lowering the incentives to invest in rural telecommunications. The financial implications of wiring a vast area for low telephone traffic causes most telephone service providers to ignore or delay offering telephone service to those regions. Still, it is known that telecommunications are essential to the economic development of a region, and that traffic increases rapidly as soon as the service is available. A satellite-based telephone network can provide efficient long distance telephone service to remote rural communities at a lower cost than land-based wired networks in most cases. Mobile satellite systems already provide this service, but are limited in capacity and charge high per- minute fees for the satellite link. Small earth stations and GEO satellites can provide this service more efficiently and at lower cost. A methodology to optimize the network performance has been developed. A set of economic models to evaluate different combinations of network topologies and multiple access techniques have been implemented, and a technical-economic assessment has been performed for the different technologies under different traffic scenarios. Traffic intensity, network size and per-minute user costs have been optimized to achieve the network's economic break-even point under different conditions and constraints. The general behavior of fixed-assignment Single Channel per Carrier SCPC), fixed-assignment Multiple Channel per Carrier (MCPC) and demand-assignment SCPC star networks, as well as demand-assignment SCPC mesh networks has been analyzed. Important parameters have been identified in order to improve the process of effective and cost-efficient satellite rural telephone network design. / Ph. D.