Distributed energy is an attractive alternative to typical centralized energy sources specifically for remote locations not accessible to the electricity grid. With the continued advancement into new renewable technologies like solar, wind, fuel cell etc., off-grid standalone systems are becoming more attractive and even compeating on a cost basis for rural locations. Along with the environmental and sustainable movement, these technologies are only going to get more and more popular as time goes on. Power electronic converters are also advancing which will help the shift in electricity options. Creating innovative power electronic systems will be important when moving toward smaller, more e cient and higher power density solutions. As such, this thesis will aim to design and create an integrated power electronic system for an o -grid standalone solar application designed for remote rural locations with no access to electricity, or in locations which could bene t from such a system. It is designed for a DC input source from 24V-40V, such as a solar panel, and can operate four di erent loads; one 12V-24V 100 W DC load, charge a 48V battery, run three 5V cell phone charger outputs and run one 230V, 50Hz, 1 kW AC load. A boost converter, buck converter, phase shifted full bridge isolated DC-DC converter and a single phase inverter are implimented in the integrated system to achieve these outputs. A comparison of similar products on the market are presented and compared with the proposed design by showing the product speci cations, advantages and disadvantages of each. A discussion of each converter in the system is presented and will include operation, design and component selection. An in-depth design process for the inductor within the boost converter is presented and will cover core, winding design and an optimization algorithm using the Genetic Algorithm (GA) is used to compare di erent ferrite based C-C shaped inductors. More speci cally, the core material selected is Ferroxcube 3C97 and the inductor comparions are between di erent Litz bundled windings from New England Wire Tecnologies and a customized rectangular winding. The GA optimizes around the lowest volume by comparing the di erent inductor designs using the di erent Litz winding constructions and the custom rectangular winding constrictuion. The rectangular winding achieves the lowest volume and will be compared with a three phase interleaved boost design implimenting a CoilCraft inductor. The buck converter is the simplest converter and is designed using the traditional methods in literature. An in-depth design process for the phase shifted full bridge converter is also done wherein the zero voltage switching (ZVS) is achieved. The DC-AC inverter is the last converter designed within the integrated system and covers input capacitor sizing, and output lter design. There are speci c distributed energy standards that must be followed when connecting loads to the system and so the purpose of the lter is to lter out the voltage harmonics. The control techniques for each converter is also discussed and shown to operate in both simulation and in experimentally. The losses within the system are discussed and the required equations are de ned / Thesis / Master of Applied Science (MASc)

This thesis examines the development of DC-DC converters that are suitable for Module Integrated Converters, (MICs), in grid interactive photovoltaic (PV) systems, and especially concentrates on the study of the half bridge dual converter, which was previously developed from the conventional half bridge converter. Both hard-switched and soft-switched half bridge dual converters are constructed, which are rated at 88W each and transform a nominal 17.6Vdc input to an output in the range from 340V to 360Vdc. An initial prototype converter operated at 100kHz and is used as a base line device to establish the operational behaviours of the converter. The second hard-switched converter operated at 250kHz and included a coaxial matrix transformer that significantly reduced the power losses related to the transformer leakage inductance. The soft-switched converter operated at 1MHz and is capable of absorbing the parasitic elements into the resonant tank. Extensive theoretical analysis, simulation and experimental results are provided for each converter. All three converters achieved conversion efficiencies around 90%. The progressive increases in the operation frequency, while maintaining the conversion efficiency, will translate into the reduced converter size and weight. Finally different operation modes for the soft-switched converter are established and the techniques for predicting the occurrence of those modes are developed. The analysis of the effects of the transformer winding capacitance also shows that soft switching condition applies for both the primary side mosfets and the output rectifier diodes.

This thesis examines converter topologies suitable for Module Integrated Converters (MICs) in grid interactive photovoltaic (PV) systems, and makes a contribution to the development of the MIC topologies based on the two-inductor boost converter, which has received less research interest than other well known converters. The thesis provides a detailed analysis of the resonant two-inductor boost converter in the MIC implementations with intermediate constant DC links. Under variable frequency control, this converter is able to operate with a variable DC gain while maintaining the resonant condition. A similar study is also provided for the resonant two-inductor boost converter with the voltage clamp, which aims to increase the output voltage range while reducing the switch voltage stress. An operating point with minimized power loss can be also established under the fixed load condition. Both the hard-switched and the soft-switched current fed two-inductor boost converters are developed for the MIC implementations with unfolding stages. Nondissipative snubbers and a resonant transition gate drive circuit are respectively employed in the two converters to minimize the power loss. The simulation study of a frequency-changer-based two-inductor boost converter is also provided. This converter features a small non-polarised capacitor in a second phase output to provide the power balance in single phase inverter applications. Four magnetic integration solutions for the two-inductor boost converter have also been presented and they are promising in reducing the converter size and power loss.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work presents an analysis and design of two Light Emitting Diode (LED) drivers topologies based on static switched converters aiming to avoid using electrolytic capacitors. Considering the low lifetime of electrolytic capacitors compared to LEDs, the topologies aims for reducing the storage capacitance and replaces it by a longer lifetime capacitor, increasing the overall system life span. A Proportional Integral controller is designed to reduce the output current ripple. Consequently, it reduces the bus voltage ripple which allows working with reduced bus capacitances. The input current harmonic distortion limit must be observed. The power factor correction stage is based on a Single Ended Primary Inductance Converter (SEPIC) operating under discontinuous conduction mode (MCD) for both topologies. The power control (PC) stage is performed by a Buck converter for the SEPIC-Buck topology and by a Ćuk converter for the SEPIC-Ćuk topology. These PC converters present output current source behavior, suitable for LED application. Two LED driver prototypes are implemented and the results present high efficiency and a 50% current ripple on the LED. Furthermore a simple dimming strategy is proposed and implemented. / Este trabalho apresenta uma análise e projeto para duas topologias de circuito de acionamento para Diodos Emissores de Luz (LED) utilizando conversores estáticos integrados com o objetivo de evitar a utilização de capacitores eletrolíticos. Considerando a baixa vida útil dos capacitores eletrolíticos, se comparada à dos LEDs, as topologias buscam reduzir a capacitância de barramento tornando possível a utilização de capacitores de maior vida útil, aumentando a vida útil do sistema como um todo. Um controlador Proporcional Integral é projetado para reduzir a ondulação na corrente de saída. Consequentemente, a ondulação da tensão de barramento é reduzida permitindo o uso de capacitâncias de barramento reduzidas. O limite da distorção harmônica da corrente de entrada deve ser observado. O estágio de correção do fator de potência é baseado no Conversor com Indutância Simples no Primário (SEPIC) operando no modo de condução descontínuo (MCD) para ambas as topologias. O estágio de controle de potência (PC) é realizado por um conversor Buck para a topologia SEPIC-Buck e por um conversor Ćuk para a topologia SEPIC-Ćuk. Os conversores do estágio PC apresentam característica de fonte de corrente na saída, conveniente para a utilização de LEDs. Dois protótipos para circuitos de acionamento para LEDs são implementados e os resultados apresentam alta eficiência e uma ondulação de 50% na corrente dos LEDs. Além disso, um circuito de controle da intensidade luminosa de bastante simplicidade é proposto e implementado.