Este trabalho tem como objetivo reunir, registrar, estudar e comparar as estratégias de controle utilizadas em inversores para fontes ininterruptas de energia, efetuado através de levantamento bibliográfico, englobando estratégias antigas (implementadas muitas vezes na forma analógica) e recentes (com implementação digital). É realizada comparação dos desempenhos, determinados analiticamente por modelamento e/ou por simulação computacional, entre algumas estratégias de controle. É apresentado um método para a implementação digital de um inversor monofásico para fontes ininterruptas de energia com transformador na saída. O método utilizado consiste de: Análise e modelagem dos controladores e planta, adotando-se critérios para o ajuste dos respectivos parâmetros; Simulação no modo de tempo contínuo; Roteiro da discretização para possibilitar implementação digital; Simulação em tempo discreto; Implementação em protótipo experimental. O controle é realizado com uma estratégia de múltiplas malhas, usando três malhas: uma malha interna de corrente usando controlador proporcional com compensação feedforward da perturbação da tensão de saída no controle da corrente e uma malha externa de tensão com um controlador proporcional + ressonante. Uma terceira malha de controle externa a malha de tensão é adicionada para prevenir a saturação do núcleo do transformador. O inversor é implementado através de um arranjo físico de baixa potência, possibilitando comparação dos resultados de simulação e experimentais. / This dissertation intends to collect, register, study and compare control strategies used in inverters for uninterrupted power supplies. Older control strategies, which use analogical control, as well as contemporary ones, which use digital control, were studied. A performance comparison between some strategies is made using analytical modeling and computational simulation. It is proposed a method for implementation of digital controller for a one-phase inverter with output transformer for uninterruptible power supplies applications. The method consists on: Analysis and modeling of plant and controllers, adopting criteria for parameters adjust; Continuous time computational simulation; Discretization guide for digital implementation; Discrete time computational simulation; Experimental prototype implementation. Control uses a multiloop approach, with three control loops: An internal current loop with proportional controller and feed-forward output voltage disturbance compensation, an external voltage loop using a proportional + resonant controller, and a third external loop to prevent the saturation of the output transformer. A low power experimental setup of the inverter is implemented, allowing comparison of simulated and experimental results.

Abstract not available

<p>Switch Mode Power Supplies are very important components in present day electronics and have continued to thrive and grow over the past 25 years. This thesis looks inside how the SMPS have evolved over the passage of years with special emphasis to the Synchronous Buck Converter. It also discusses why there is a strong potential to further the study related to designs based around a Synchronous Buck Converter for portable applications. The main objective of the thesis is to look into the controller design for minimizing size, enhancing efficiency and reliability of power converters in portable electronic equipment such as mobile phones and PDAs. The thesis aims to achieve this using a 90 nm process with an input voltage of 1.55V and an output of 1V with a power dissipation of 200mW.</p>

Power and timing requirements are becoming more and more stringent as applications move from less mobile devices to more mobile ones. As such, it is important to optimize these applications as much as possible in order to provide the best solution that is low power and low latency. Although there are many different techniques to achieve a low power, low latency solution, this thesis focuses specifically on low power scheduling at the behavioral level where resource-constrained scheduling is the technique of choice since it directly considers the resource limitations of mobile devices. Conventional resource-constrained scheduling schemes are concerned with minimizing the latency or improving the speed of an algorithm--represented by a data flow graph (DFG)--given a limitation on resources. However, these conventional resource-constrained scheduling schemes are no longer applicable since power has grown to be a major issue, especially in mobile devices. Hence, the conventional resource-constrained scheduling schemes gave way to current resource-constrained scheduling schemes that utilize multiple voltages, which work to find a balance between speed and power. These current multiple voltage schemes use various techniques to balance and meet the speed and power requirements. But while they do a good job of meeting these requirements, they fail to address a new issue that is beginning to surface the number of memory registers needed. Therefore, to address this new arising issue, this paper presents a novel resource-constrained scheduling scheme that balances the speed, power, and register requirements. This algorithm is compared to both a conventional resource-constrained scheduling scheme and a current resource-constrained scheduling scheme with multiple voltages to show that it performs better in finding a scheduling solution. Benchmark results show that, on average, our algorithm has a better power savings while keeping the maximum number of registers needed and the latency low compared to conventional resource-constrained scheduling schemes and current resource-constrained scheduling schemes utilizing just multiple voltages. / Graduation date: 2004

Switch Mode Power Supplies are very important components in present day electronics and have continued to thrive and grow over the past 25 years. This thesis looks inside how the SMPS have evolved over the passage of years with special emphasis to the Synchronous Buck Converter. It also discusses why there is a strong potential to further the study related to designs based around a Synchronous Buck Converter for portable applications. The main objective of the thesis is to look into the controller design for minimizing size, enhancing efficiency and reliability of power converters in portable electronic equipment such as mobile phones and PDAs. The thesis aims to achieve this using a 90 nm process with an input voltage of 1.55V and an output of 1V with a power dissipation of 200mW.

The primary focus of this thesis is to present a simple and practical implementation of an optimal-time response controller for multiphase interleaved dc-dc SMPS. This novel solution enables equal current sharing between phases not only in steady-state, but also during load transients, as well as bump-less transition between those two states. A digital voltage loop and multiple analog peak current programmed mode current loops are combined to implement a capacitor charge balance control algorithm with fairly simple hardware. This algorithm provides recovery from a disturbance in a single on-off switching action, which is performed in virtually the fastest possible time. The hybrid interface between the loops is provided through a structure combining a sample-and-hold circuit and a relatively slow successive-approximation DAC that provides control signals for all the loops in the system. Furthermore, for operation under light load conditions, the controller automatically switches into simply implemented pulse-frequency mode of operation.

Environmental concerns have renewed the interest in electric vehicles. To gain widespread use, electric vehicles will also have to offer good performance and be reasonably priced. AC drive systems using modern semiconductors can provide efficient operation at the required power levels, but their cost at present is still too high. This paper discusses the development of an AC induction motor drive system which potentially lowers cost by using a digital controller. The controller is shown to implement a high performance field-oriented control, while keeping a low parts count by maximizing use of interface circuits which are integrated onto the microprocessor chip. Cost is further reduced by designing the system to reuse motor control components for battery charging and eliminate the need for external circuits. Experimental results are presented for a low power prototype system. / Graduation date: 1994

The primary focus of this thesis is to present a simple and practical implementation of an optimal-time response controller for multiphase interleaved dc-dc SMPS. This novel solution enables equal current sharing between phases not only in steady-state, but also during load transients, as well as bump-less transition between those two states. A digital voltage loop and multiple analog peak current programmed mode current loops are combined to implement a capacitor charge balance control algorithm with fairly simple hardware. This algorithm provides recovery from a disturbance in a single on-off switching action, which is performed in virtually the fastest possible time. The hybrid interface between the loops is provided through a structure combining a sample-and-hold circuit and a relatively slow successive-approximation DAC that provides control signals for all the loops in the system. Furthermore, for operation under light load conditions, the controller automatically switches into simply implemented pulse-frequency mode of operation.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 253-261). Available also in a digital version from Dissertation Abstracts.

Informational equipment are difficult systems which performance reliability depends on a number of internal and external factors. One of the most important external factors is the quality of supplied electricity. Dependence of performance reliability of informational equipment upon the quality of supplied electricity, the impact of equipment themselves on the feeding system/net are discussed in this work. The standards of quality of electricity are overviewed, the deviations of voltage and their influence over informational equipment are evaluated. Means of increase of reliability, their structure and course of performance are described, their advantages and weaknesses are specified. Electrical ground system has major influence over reliable performance. In case of incorrect installation of the system it is possible to cause system foul-ups or even put a human life at risk. The influence of informational equipment over feeding net/system is evaluated in this work, the example of calculation of workload is presented.