7,268 research outputs found

    Razvoj robusnog diskretnog regulatora za silazni pretvaraÄŤ s dvostrukom frekvencijom preklapanja

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    A discrete controller is designed for high efficiency double frequency buck converter. This double frequency buck converter is comprised of two buck cells: one works at high frequency, and another works at low frequency. It operates in a way that current in the high frequency switch is diverted through the low frequency switch. Thus, the converter can operate at very high frequency without adding any additional control circuits. Moreover, the switching loss of the converter remains small. The proposed converter exhibits improved steady -- state and transient response with low switching loss. A digital compensator further improves the dynamic performance of the closed loop system. Simulation of digitally controlled double frequency buck converter is performed with MATLAB / Simulink. Experimental results are given to demonstrate the effectiveness of the controller using LabVIEW with a Data Acquisition Card (NI - 9221).Dikretni regulator je projektiran za postizanje visoke efikasnosti silaznog pretvarača s dvostrukom frekvencijom preklapanja. Ovaj silazni pretvarač s dvostrukom frekvencijom preklapanja sastoji se od dvaju ćelija: po jedna za rad na visokim i niskim frekvencijama preklapanja. Regulator funkionira tako da se struja preklapanja na visokim frekvencijama preusmjerava kroz prekidač za preklapanje na niskim frekvencijama. Tako pretvarač može funkcionirati na vrlo visokim frekvencijama bez dodatnih upravljačkih krugova. štoviše, gubici prekidanja pretvarača ostaju mali. Prikazani pretvarač pokazuje poboljšanja kod odzivu u ustaljenom stanju te u prijelaznim pojavama uz male gubitke prilikom prekidanja. Digitalni kompenzator nadalje poboljšava dinamičke performanse sustava u zatvorenom krugu. Simulacije digitalno upravljanog silaznog pretvarača s dvostrukom frekvencijom preklapanja su provedene korištenjem MATLAB / Simulink-a. Eksperimentalni rezultati su prikazani kako bi se demonstrirala efikasnost regulatora korištenjem LabVIEW-a i kartice za prikupljanje podataka (NI - 9221)

    Double-frequency buck converter as a candidate topology for integrated envelope elimination and restoration applications in power supply of RFPAs

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    This paper proposes the use of double-frequency (DF) buck converter architecture consisting of a merged structure of high and low frequency buck cells as a candidate topology for envelope elimination and restoration (EER) applications and integrated power supply of RF power amplifiers (RFPA) to obtain favorable tradeoffs in terms of efficiency, switching ripple, bandwidth, and tracking capability. It is shown that having two degrees of freedom in designing the DF buck helps to achieve high efficiency, low output ripples, and tracking capability with low ripples, simultaneously. A comparison analysis is done with regards to the mentioned performance indexes with the standard and three-level buck converters; in addition, the results are validated in HSPICE in BSIM3V3 0.35-µm CMOS process.Peer ReviewedPostprint (author's final draft

    PWM Control of a Buck Converter with an Amorphous Core Coil

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    Pulse-width modulation is widely used to control electronic converters. One of the most topologies used for high DC voltage/low DC voltage conversion is the Buck converter. It is obtained as a second order system with a LC filter between the switching subsystem and the load. The use of a coil with an amorphous magnetic material core instead of air core lets design converters with smaller size. If high switching frequencies are used for obtaining high quality voltage output, the value of the auto inductance L is reduced throughout the time. Then, robust controllers are needed if the accuracy of the converter response must not be affected by auto inductance and load variations. This paper presents a robust controller for a Buck converter based on a state space feedback control system combined with an additional virtual space variable which minimizes the effects of the inductance and load variations when a not-toohigh switching frequency is applied. The system exhibits a null steady-state average error response for the entire range of parameter variations. Simulation results are presented

    Multiport power electronics circuitry for integration of renewable energy sources in low power applications : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Electrical Engineering at Massey University, Palmerston North, New Zealand

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    The increasing demand for electricity and the global concern about environment has led energy planners and developers to explore and develop clean energy sources. Under such circumstances, renewable energy sources (RES) have emerged as an alternative source of energy generation. Immense development has been made in renewable energy fields and methods to harvest it. To replace conventional generation system, these renewable energy sources must be sustainable, reliable, stable, and efficient. But these sources have their own distinguished characteristics. Due to sporadic nature of renewable energy sources, the uninterrupted power availability cannot be guaranteed. Handling and integration of such diversified power sources is not a trivial process. It requires high degree of efficiency in power extraction, transformation, and utilization. These objectives can only be achieved with the use of highly efficient, reliable, secure and cost-effective power electronics interface. Power electronics devices have made tremendous developments in the recent past. Numerous single and multi-port converter topologies have been developed for processing and delivering the renewable energy. Various multiport converter topologies have been presented to integrate RES, however some limitations have been identified in these topologies in terms of efficiency, reliability, component count and size. Therefore, further research is required to develop a multiport interface and to address the highlighted issues. In this work, a multi-port power electronics circuitry for integration of multiple renewable energy sources is developed. The proposed circuitry assimilates different renewable sources to power up the load with different voltage levels while maintaining high power transfer efficiency and reliability with a simple and reliable control scheme. This research work presents a new multiport non-isolated DC-DC buck converter. The new topology accommodates two different energy sources at the input to power up a variable load. The power sources can be employed independently and concurrently. The converter also has a bidirectional port which houses a storage device like battery to store the surplus energy under light load conditions and can serve as an input source in case of absence of energy sources. The new presented circuitry is analytically examined to validate its effectiveness for multiport interface. System parameters are defined and the design of different components used, is presented. After successful mathematical interpretation, a simulation platform is developed in MATLAB/Simscape to conduct simulations studies to verify analytical results and to carry out stability analysis. In the final stage, a low power, low voltage prototype model is developed to authenticate the results obtained in simulation studies. The converter is tested under different operating modes and variable source and load conditions. The simulation and experimental results are compiled in terms of converter’s efficiency, reliability, stability. The results are presented to prove the presented topology as a highly reliable, stable and efficient multiport interface, with small size and minimum number of components, for integration of renewable energy sources

    Passive Power Filters

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    Power converters require passive low-pass filters which are capable of reducing voltage ripples effectively. In contrast to signal filters, the components of power filters must carry large currents or withstand large voltages, respectively. In this paper, three different suitable filter structures for d.c./d.c. power converters with inductive load are introduced. The formulas needed to calculate the filter components are derived step by step and practical examples are given. The behaviour of the three discussed filters is compared by means of the examples. Practical aspects for the realization of power filters are also discussed.Comment: 25 pages, contribution to the 2014 CAS - CERN Accelerator School: Power Converters, Baden, Switzerland, 7-14 May 201

    Morphing Switched-Capacitor Converters with Variable Conversion Ratio

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    High-voltage-gain and wide-input-range dc-dc converters are widely used in various electronics and industrial products such as portable devices, telecommunication, automotive, and aerospace systems. The two-stage converter is a widely adopted architecture for such applications, and it is proven to have a higher efficiency as compared with that of the single-stage converter. This paper presents a modular-cell-based morphing switched-capacitor (SC) converter for application as a front-end converter of the two-stage converter. The conversion ratio of this converter is flexible and variable and can be freely extended by increasing more SC modules. The varying conversion ratio is achieved through the morphing of the converter's structure corresponding to the amplitude of the input voltage. This converter is light and compact, and is highly efficient over a very wide range of input voltage and load conditions. Experimental work on a 25-W, 6-30-V input, 3.5-8.5-V output prototype, is performed. For a single SC module, the efficiency over the entire input voltage range is higher than 98%. Applied into the two-stage converter, the overall efficiency achievable over the entire operating range is 80% including the driver's loss

    Driving electronics for OLED lighting

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    This paper proposes the concept of integrating an OLED (foil) and its driving electronics into one module. A complete light system consisting of these modules is the ultimate goal of this work. The main focus in this article is on the design of the driver chip and the circuit implementation. The measurement results confirm that it is possible to control the light output of the different modules

    A three-switch high-voltage converter

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    A novel single active switch two-diodes high-voltage converter is presented. This converter can operate into a capacitor-diode voltage multiplier, which offers simpler structure and control, higher efficiency, reduced electromagnetic interference (EMI), and size and weight savings compared with traditional switched-mode regulated voltage multipliers. Two significant advantages are the continuous input current and easy isolation extension. The new converter is experimentally verified. Both the steady-state and dynamic theoretical models are correlated well with the experimental dat
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