Partiendo de un conjunto de modelos de pequeña señal discretos, correspondientes a varios regímenes de trabajo de un convertidor continua-continua, una base de reglas borrosas se encarga, según esta propuesta, de realizar la generalización de la descripción dinámica de dicho sistema para cualquier punto de trabajo. Para la obtención del conjunto representativo de regímenes de dimensión óptima, se propone una metodología de selección. Este modelo generalizado permite plantear una propuesta de control de estos sistemas a partir de la selección por inferencia borrosa de la ganacia óptima de realizmentación basándose en el conjunto correspondiente de leyes de control locales. Para el lazo cerrado obtenido, se plantea una condición suficiente de estabilidad. Se ha realizado un estudio de aplicación de esta propuesta sobre el convertidos de topología Buck, comparándose los resultados de distintas pruebas con los obtenidos con otros esquemas de regulación, como el control en modo corriente, observándose notables mejoras en las prestaciones obtenidas con el controlador propuesto. / Carbonell Cortés, PJ. (1999). Técnicas de control borroso basadas en modelos locales aplicadas a convertidores dc/dc conmutados. Aplicación al convertidor buck [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/4641 / Palancia

abstract: This work analyzes and develops a point-of-load (PoL) synchronous buck converter using enhancement-mode Gallium Nitride (e-GaN), with emphasis on optimizing reverse conduction loss by using a well-known technique of placing an anti-parallel Schottky diode across the synchronous power device. This work develops an improved analytical switching model for the GaN-based converter with the Schottky diode using piecewise linear approximations. To avoid a shoot-through between the power switches of the buck converter, a small dead-time is inserted between gate drive switching transitions. Despite optimum dead-time management for a power converter, optimum dead-times vary for different load conditions. These variations become considerably large for PoL applications, which demand high output current with low output voltages. At high switching frequencies, these variations translate into losses that contribute significantly to the total loss of the converter. To understand and quantify power loss in a hard-switching buck converter that uses a GaN power device in parallel with a Schottky diode, piecewise transitions are used to develop an analytical switching model that quantifies the contribution of reverse conduction loss of GaN during dead-time. The effects of parasitic elements on the dynamics of the switching converter are investigated during one switching cycle of the converter. A designed prototype of a buck converter is correlated to the predicted model to determine the accuracy of the model. This comparison is presented using simulations and measurements at 400 kHz and 2 MHz converter switching speeds for load (1A) condition and fixed dead-time values. Furthermore, performance of the buck converter with and without the Schottky diode is also measured and compared to demonstrate and quantify the enhanced performance when using an anti-parallel diode. The developed power converter achieves peak efficiencies of 91.7% and 93.86% for 2 MHz and 400 KHz switching frequencies, respectively, and drives load currents up to 6A for a voltage conversion from 12V input to 3.3V output. In addition, various industry Schottky diodes have been categorized based on their packaging and electrical characteristics and the developed analytical model provides analytical expressions relating the diode characteristics to power stage performance parameters. The performance of these diodes has been characterized for different buck converter voltage step-down ratios that are typically used in industry applications and different switching frequencies ranging from 400 KHz to 2 MHz. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2020

The power requirements for microprocessors have been increasing per Moore's Law. According to International Technology Roadmap (ITRS), Voltage Regulator Module (VRM) for microprocessors will be about 200 W at 1 V output in 2010. With the VRM’s topology of synchronous buck, serious technical challenges such as small duty cycle, high switching frequencies, and higher current demands, contribute to decreased power density and increased cost. This thesis proposes a Continuous Input Current Multiphase Interleaved Buck topology to solve the technical challenges of powering future microprocessors. This new topology is aimed to improve past topologies by providing continuous input current and improved efficiency. An open loop system of the proposed new topology is simulated using OrCAD PSpice to evaluate the performance criteria of the VRM. A hardware prototype of a four-phase Continuous Input Current Multiphase Interleaved Buck Converter is constructed and tested to assess the targeted improvements.

The future of microprocessors is unknown. Over the past 40 years, their historical trend has been for adopting smaller and more powerful designs that drive the world that we live in today. The state of the microprocessor business today faces a crossroad, wishing to continue on the historical trend of doubling the number of transistors on a chip every 18 months (Moore’s Law) but also facing the realistic task of needing to power these sophisticated devices. With the low voltages and high currents that are required for these microprocessors to operate, it poses a difficult task for the future designers of the voltage regulators that are used to power these microprocessors. The technique that has been widely adopted as the preferred method to power these devices is called a multiphase buck converter, or multiphase voltage regulator. This thesis is a continuation of and is aimed to improve previous work done by two former Cal Poly students, Kay Ohn and Ian Waters. A new design that uses an interleaving control scheme, careful component selection, an input LC filter, and a reduction in board size seeks to improve the efficiency, input current noise, and increase the current density of the original design. Research was first conducted to determine how to best make such improvements. The design phase ensued, which used design calculations and simulations to test if the proposed multiphase topology was plausible. Once the theory was fully proven, a real hardware circuit was created and tested to confirm the results. The results yield a multiphase design with improved input noise filtering, greater efficiency, more equal current sharing, and higher current density as compared to previous topologies in this field. Parameters such as output voltage ripple, load and line regulation, and transient response remained excellent, as they were with the previous work.

No description available.

The power consumption of smart camera in car black box varies significantly between light load and heavy load. The high efficiency voltage regulator is necessary in prolong the life of smart camera battery. Since the smart camera only recording the video when car is driving, the most time of the smart camera works in the sleep mode. Hence the light load efficiency is important in this application, however, conventional buck converter usually have high efficiency at heavy load but poor efficiency at light load. To increase the light load efficiency of buck converter, this research continues Yeago's two phase buck converter with optimum phase selection control and Zhao's two mode buck converter to further improve the light load efficiency for the target application. With 5V input voltage and 1.2V output voltage, the proposed two-mode synchronous buck converter can supply the load power from 12mW to 1.44W. To improve the light load efficiency of conventional buck converter, the proposed design applied Wei's baby buck concept to provide another light load power stage to reduce the switching loss and driving loss at light load. Then, the variable frequency ripple-based constant on-time control with discontinuous conduction mode (DCM) in light load is applied to the baby-buck mode to reduce the switching frequency to further reduce the switching loss. Also, the baby-buck mode uses the synchronous buck topology to remove the diode in asynchronous converter to increase the efficiency at light load. Finally, a sensorless mode selector remove the sensing resistor in power stage to increase the efficiency for entire load range, especially for the heavy load. The mode selector can select the optimum mode for different load condition, and the opposite mode would completely shut down to save the loss. The proposed design is implement in CMOS 0.25um technology. The proposed monolithic buck converter which include the power stage of heavy buck mode, baby-buck mode and the controller is fabricated. The measurement result shows the close loop efficiency varies from 70%-83% toward the entire load range. / Master of Science

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / This work presents procedures for modeling a Buck-Boost converter based on offline parametric identification techniques, with employment of black box and gray box models. For the identification of the control-to-output-voltage transfer function, the nonlinear Hammerstein model is employed, a particularly interesting structure to identify DC-DC converters for its ability to incorporate nonlinear static characteristic aside from the dynamic behavior of the plant. The identification of the mentioned transfer function is achieved from input and output data, obtained in simulations. In order to identify transfer function parameters, a restricted least squares algorithm is used. As for the identification of the control-to-inductor-current transfer function, a linear black box first order model is considered, with its parameters being determined from systemâs frequency response. In order to show the modelâs utility, a control system is designed based on the identified expressions. The control system employed is the digital version of type 3 compensator for the voltage loop and type 2 compensator for the current loop, both operating under or logics. The identification results of the system presented excellent agreement between the obtained parametric models and the converterâs behavior, showing the reliability of the identification techniques employed in this work. Furthermore, the control system designed from the identified transfer functions presented good performance, providing stability and quick disturbance rejection, bolstering the validity of parametric identification methods applied to the Buck-Boost converter. / Este trabalho apresenta procedimentos para a modelagem de um conversor Buck-Boost com base em tÃcnicas de identificaÃÃo paramÃtricas offline com emprego de modelos matemÃticos tipo caixa preta e caixa cinza. Para a identificaÃÃo da funÃÃo de transferÃncia que relaciona a tensÃo de saÃda e a razÃo cÃclica, à empregado o modelo nÃo linear de Hammerstein, estrutura particularmente interessante para aplicaÃÃo em identificaÃÃo de conversores CC-CC por incorporar a caracterÃstica estÃtica nÃo linear da planta de forma dissociada ao seu comportamento dinÃmico. A identificaÃÃo da funÃÃo de transferÃncia citada à feita a partir de dados de entrada e saÃda do sistema, medidos em simulaÃÃo. Para determinaÃÃo dos parÃmetros da funÃÃo de transferÃncia que relaciona a tensÃo de saÃda e a razÃo cÃclica, à utilizado um algoritmo de mÃnimos quadrados nÃo recursivo com restriÃÃes. Quanto à identificaÃÃo da funÃÃo de transferÃncia que relaciona a corrente no indutor e a razÃo cÃclica, à empregado um modelo caixa preta linear de primeira ordem, sendo os parÃmetros de tal modelo determinados a partir da resposta em frequÃncia do sistema. Visando mostrar a utilidade dos modelos paramÃtricos, à realizado um projeto de controle com base nas expressÃes identificadas. O sistema de controle adotado à a versÃo digital de um compensador tipo 3 para a malha de tensÃo e de um compensador tipo 2 para a malha de corrente, que operam de forma alternada segundo a lÃgica ou. Os resultados de identificaÃÃo do sistema apresentam uma excelente concordÃncia entre os modelos paramÃtricos obtidos e o comportamento do conversor, mostrando a confiabilidade das tÃcnicas de identificaÃÃo empregadas nesse trabalho. Adicionalmente, o sistema de controle projetado a partir das funÃÃes de transferÃncia estimadas apresentou bom desempenho, garantindo estabilidade e rÃpida rejeiÃÃo a distÃrbios, reforÃando a validade dos mÃtodos de identificaÃÃo paramÃtrica aplicados ao conversor Buck-Boost.

This thesis investigates a relatively new method for harvesting wind energy by using flexible piezoelectric polymers with additional sails to increase their ability to harvest wind energy. This paper also introduces a new topology deemed the “stacked buck” that allows for multiple inputs to a system with a single output. Derivations and analysis detail the workings of the “stacked buck” with a laboratory test to show a working model. This paper also reports another experiment done in a wind tunnel to analyze the capability of the piezoelectric polymers as sources to the “stacked buck” topology with measurements of the power output. The results of this thesis demonstrate that because the design is very modular, it is possible to scale the proposed wind energy harvesting system for small power applications.

<p>The purpose of this degree project was to build laboratory equipment for a new course in power electronics that starts this autumn 2010 at Uppsala University. The equipment is intended for student labs and it covers the most important areas of the course including rectifying, buck-/boost-converters and PWM-modulation. It is built as one sealed unit where all the electronics are built-in but visible and it has a connection board where students safely can connect the different circuits. The project has advanced from theoretical studies of circuit design, choosing of components and simulations to drawing the printed circuit board (PCB), soldering, case building, final testing and troubleshooting - basically most steps from an early idea to a final product. Measurements on the final product gave about the same results as the earlier simulations of the circuits and the result is overall satisfying.</p> / <p>Syftet med det här examensarbetet var att bygga laborationsutrustning till en ny kurs i kraftelektronik som börjar hösten 2010 på Uppsala Universitet. Utrustningen är avsedd för studentlaborationer och den täcker de viktigaste delarna av kursen inklusive likriktning, buck-/boost-omvandlare och pulsbreddsmodulering (PWM). Laborationsutrustningen är byggd som en sluten enhet där all elektronik är inbyggd men synlig och den har en kopplingsplatta där studenterna säkert kan koppla ihop olika kretsar. Projektet har sträckt sig från teoretiska studier inklusive kretsdesign, komponentval och simuleringar till ritande av kretskortet (PCB-kortet), lödning, byggande av höljet, sluttestning och felsökning - i huvudsak de flesta stegen från en tidig idé till en färdig produkt. Mätningar på den färdiga produkten är ganska lika de tidigare simuleringarna av kretsarna och resultatet är totalt sett tillfredställande.</p>

The purpose of this degree project was to build laboratory equipment for a new course in power electronics that starts this autumn 2010 at Uppsala University. The equipment is intended for student labs and it covers the most important areas of the course including rectifying, buck-/boost-converters and PWM-modulation. It is built as one sealed unit where all the electronics are built-in but visible and it has a connection board where students safely can connect the different circuits. The project has advanced from theoretical studies of circuit design, choosing of components and simulations to drawing the printed circuit board (PCB), soldering, case building, final testing and troubleshooting - basically most steps from an early idea to a final product. Measurements on the final product gave about the same results as the earlier simulations of the circuits and the result is overall satisfying. / Syftet med det här examensarbetet var att bygga laborationsutrustning till en ny kurs i kraftelektronik som börjar hösten 2010 på Uppsala Universitet. Utrustningen är avsedd för studentlaborationer och den täcker de viktigaste delarna av kursen inklusive likriktning, buck-/boost-omvandlare och pulsbreddsmodulering (PWM). Laborationsutrustningen är byggd som en sluten enhet där all elektronik är inbyggd men synlig och den har en kopplingsplatta där studenterna säkert kan koppla ihop olika kretsar. Projektet har sträckt sig från teoretiska studier inklusive kretsdesign, komponentval och simuleringar till ritande av kretskortet (PCB-kortet), lödning, byggande av höljet, sluttestning och felsökning - i huvudsak de flesta stegen från en tidig idé till en färdig produkt. Mätningar på den färdiga produkten är ganska lika de tidigare simuleringarna av kretsarna och resultatet är totalt sett tillfredställande.