The United Nations has declared 2012 the ``International Year of Sustainable Energy for All''. A substantial portion of the world's population (some 1.3 billion people) currently live without electricity and development efforts to reach them are progressing relatively slowly. This thesis follows the development of a technology which can enable community owned and operated microgrids to emerge based solely on the local supply and demand of that community. Although this thesis ends with the technical analysis of a DC/DC converter, there is a significant amount of background to cover in order to properly understand the context in which it will be used. After providing an introduction into typical rural electrification efforts and pointing out some of the shortcomings of these projects, this thesis introduces some cutting edge efforts which combine solar home system technology with cellular technology and discusses the benefits of such a marriage of technology. Next, the research proposes some tweaks to this novel technology and provides a high-level economic demonstration of the spread of solar home systems in a community based on these modifications. It then takes this concept even further and proposes the addition of a DC/DC converter which could turn these individual solar home systems into a proper microgrid. This thesis elaborates on the development process of simulating such a microgrid in PSCAD, including the individual components of a solar home system and the specific task of designing the converter which would form the backbone of the proposed microgrid. The final simulations and analyses demonstrate a microgrid that is both technically and economically feasible for developing world applications.

In recent years, there has been lots of emphasis put on the development of renewable energy. While considerable improvement on renewable energy has been made, there are some inherent limitations for these renewable energies. For example, for solar and wind power, there is an intermittent nature. For the fuel cell, the dynamics of electro-chemical reaction is quite slow compared to the electric load. This will not be acceptable for modern electric application, which requires constant voltage of constant frequency. This work proposed and evaluated a new power circuit that can deal with the problem of the intermittent nature and slow response of the renewable energy. The proposed circuit integrates different renewable energy sources as well as energy storage. By integrating renewable energy sources with statistical tendency to compensate each other, the effect of the intermittent nature can be greatly reduced. This integration will increase the reliability and utilization of the overall system. Moreover, the integration of energy storage solves the problem of the slow response of renewable energy. It can provide the extra energy required by load or absorb the excessive energy provided by the energy sources, greatly improving the dynamics of overall system. To better understand the proposed circuit, "Dual Active Bridge" and "Triple Active Bridge" were reviewed first. The operation principles and the modeling were presented. Analysis and design of the overall system were discussed. Controller design and stability issues were investigated. Furthermore, the function of the central controller was explained. In the end, different simulations were made and discussed. Results from the simulations showed that the proposed multi-port DC-DC power converter had satisfactory performance under different scenarios encountered in practical renewable energy application. The proposed circuit is an effective solution to the problem due to the intermittent nature and slow response of the renewable energy.

Three different chip design topics associated with their respective applications are proposed in this thesis. The first topic is the implementation of an FIFO memory design for 8-to-32 data exchange bus. An FIFO memory architecture is proposed to be utilized in data exchange between processing units which possess non-homogeneous bus widths. Neither arbiter logics nor modules are required in such a design to determine input sequences or output sequences. Hence, the delay is drastically shortened. The second topic is focused on the implementation of an analog front-end of digital cordless headset baseband controller. The integrated analog and digital interface IC provides an interface for analog and digital communication. It converts an analog signal into an 8-bit digital signal, which will be processed by the baseband controller. It also converts an 8-bit digital voice data into an analog voice signal. In addition, a built-in oscillator is included in the design, which provides a global clock signal. The third topic is to carry out an DC/DC converter with a built-in voltage detector. The converter can convert 1.5V input voltage to 2.7V output voltage. A portable system can use only one single battery to power on by this circuit. It also contains a voltage detector to indicate whether the output voltage meets the pre-determined level.

In this thesis analysis and design of a wide input range DC-DC converter is proposed along with a robust power control scheme. The proposed converter and its control is designed to be compatible to a fuel cell power source, which exhibits 2:1 voltage variation as well as a slow transient response. The proposed approach consists of two stages: a primary three-level boost converter stage cascaded with a high frequency, isolated boost converter topology, which provides a higher voltage gain and isolation from the input source. The function of the first boost converter stage is to maintain a constant voltage at the input of the cascaded DC-DC converter to ensure optimal performance characteristics with high efficiency. At the output of the first boost converter a battery or ultracapacitor energy storage is connected to take care of the fuel cell slow transient response (200 watts/min). The robust features of the proposed control system ensure a constant output DC voltage for a variety of load fluctuations, thus limiting the power being delivered by the fuel cell during a load transient. Moreover, the proposed configuration simplifies the power control management and can interact with the fuel cell controller. The simulation results and the experimental results confirm the feasibility of the proposed system.

This thesis comprises two topics : the first one is the design and implementation of FlexRay automotive communication system physical layer. The second part is the design of a high efficiency DC/DC Buck converter with sub-3 ¡Ñ VDD. The first topic discloses the physical layer design comprising the Bus Guardian and the Bus Driver used in an in-vehicle network compliant with FlexRay standards. It is realized in a mixed-signal chip using TSMC 1P6M 0.18 £gm CMOS process. Its core area is less than 0.8 mm2, and power consumption is less than 60 mW. The second topic is to design a DC to DC step-down converter, which can accommodate wide range VDD. By utilizing stacked power MOSFETs, a voltage level converter, a detector and a controller, the design is realized by a typical 1P6M 0.18 £gm CMOS process without any high voltage technology. The core area is less than 0.184 mm2, while the VDD range is up to 5 V. Since the internal reference voltage is 1 V, it can increase the output regulation range. The proposed design attains very high conversion efficiency to prolong the life time of power supply. Therefore, it can be integrated in a system chip to provide multiple supply voltage sources.

Thesis (M.S.)--University of Florida, 2005. / Title from title page of source document. Document formatted into pages; contains 74 pages. Includes vita. Includes bibliographical references.

Thesis (M.Eng.), Memorial University of Newfoundland, 2000. / Bibliography: leaves 105-109.

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002. / Includes bibliographical references (leaves 95-97). Also available in electronic version. Access restricted to campus users.

This thesis is an ongoing project of Ericsson with collaboration of Blekinge Institute of Technology [BTH], and Linneaus University [LNU] to compare the functionality and performance of three controllers Polynomial Pole Placement, PID [Proportional Integral Derivative] and PD controller in third order. This paper presents the state space modeling approach of DC-DC Buck converter. The main aim of this thesis is, by considering the buck converter system of Ericsson BMR450 with the PID, POLYNOMIAL and PD controllers at feedback loop, thus running their Matlab file with their appropiate Simulink block diagram, and comparing the three controllers performance by verifying their appropiate output graphs. The third order controller design is complicated and response is slow. The second order design is easy and gives better responses than third order Polynomial, PID and PD controllers. / As per the results point of view, the polynomial performed well than PID and PD controllers. The simulations show that the polynomial controller reaches the reference voltage very well, were the PID and PD result does not differ very much while meeting with the required reference voltage. Thus we conclude that the Polynomial controller design and results were better than the PID and PD Controllers. If we compare both the second order [4] and third order controller methods, The second order controllers are easy in design and gives better responses than third order polynomial PID and PD controllers. / ERCS.MADHU KIRAN, D.NO: 1/1/131, B.C.COLONY, MUTHUKUR, NELLORE, ANDHRA PRADESH, INDIA. PIN - 524344. THOTA. Partha Saradhi, C/O CH SUVARNA RAJU D.NO: 4-5-47, VEGIVARI CHAVADI, KOTHA PETA, WARD NO:21, KOVVUR, WEST GODAVARI,ANDHRA PRADESH, INDIA PIN - 534350,

This thesis presents the design of a step-up DC-DC converter with on-chip coupled inductors. Circuit theory of DC-DC converters in general is presented, after which a mathematical model of a step up converter is developed. A circuit implementation optimized from results of the mathematical model follows. For a completely integrated step-up converter, the inductor size is reduced by increasing the frequency of operation and using a circuit topology that employs coupled inductors. Spiral inductors are also studied to achieve maximum quality factor and inductance. A fast PWM control system is used to regulate the high-frequency converter. The fabrication was done in standard TSMC 0.18-$\mu$m digital CMOS process for four circuits, including one with a conventional topology and the others with a coupled inductor topology with varying inductor geometries. Measurement results from a fabricated prototype have been presented, demonstrating the functionality of the four circuits with coupled inductors on the fabricated chip and the improvement of the coupled solution over the conventional design. It is demonstrated that the circuits with coupled inductors have a significant improvement in performance based on conversion ratio and efficiency. Finally, the design process is evaluated and recommendations are made for future work. Furthermore, a new self-oscillating and robust control system is proposed that enables simpler and more efficient regulation for high-frequency converters such as one developed for this thesis.