Hybrid fuzzy PI controlled multi-input DC/DC converter for electric vehicle application

Power electronic interface with its effective control scheme plays a major role in the utilization of energy sources for electric vehicle application. For this purpose, a hybrid fuzzy PI based control scheme for a multiple input converter (MIC) topology is proposed. The proposed hybrid fuzzy PI controller includes a conventional PI controller at steady state and fuzzy PI at transient state. Also, the proposed control design helps in tracking a predefined speed profile to have complete realization of electric vehicle. Detailed simulation study and performance comparisons with conventional controller are performed. The results show that the developed control scheme is robust providing bidirectional power management, fast tracking capability with less steady state error, better dynamic response by enhancing the flexibility and proper utilization of energy sources. Simulation in MATLAB/SIMULINK environment is carried out to verify the performance of the multi-input converter with the developed control scheme. An experimental set-up is constructed to validate the same

Design and Modeling for DC Nanogrids

Smart grids were constructed as a means of communication to the electric grid through computer and other information technologies. This line of communication acts as gauge for a more accurate reading of power consumed. A nano grid is a model version of a smart grid with the ability to function as separate power generator. Such feature allows for this grid to power single loads and apply for special applications. A DC-DC converter was designed to apply to a nano grid which is a form of a smart grid. The converter was a single-input-multi-output converter which is taking one dc voltage and applying it to two dc output voltages. This boost converter takes the inputs and increases its voltages, leading to the outputs respectively. The nano grid utilizes this proposed converter to carry out its special characteristics. Procedures carried out in this research showed the success of the converter. Further steps include the designing of a ring and radial architecture nanogrid to form a microgrid. A comparison of results are made showing the efficiency and reliability of ring architecture layout microgrids Doing this creates a more complex system, and provide relief to multiple sources to prevent outages

Design of dual-input two phase dc/dc converter with modified pulse width modulation (mpwm)

Recently, hybrid energy source/renewable energy has attracted interest as the next-generation energy system capable of solving the problems of global warming and energy exhaustion caused by increasing energy consumption. Energy sources such as wind turbines and photovoltaic (PV) systems are intermittent, unpredictable and unregulated. For such systems, the use of multiple-input converter (MIC) has the advantage of regulating and controlling multiple-input sources. With multiple Pulsating Voltage-Source Cells (PVSC) configurations, the proposed converter can deliver power to the load individually and simultaneously. Also, it has the capability of operating either in buck, boost or buck–boost mode of operation. In addition, by proposing the enhanced Modified PWM (MPWM) switching scheme, it is able to solve the issues of the overlapping unregulated input sources. Furthermore, with the proposed multiphase configuration, the input current stresses in the switching devices are reduced and it has the benefit of a reduction in conduction losses. In addition, Zero-Voltage Switching (ZVS) technique is also employed in the proposed converter to reduce the switching loss. The proposed converter circuit is simulated by using MATLAB/Simulink and PSpice software programs. The duty cycle employed to regulate output voltage is reached from Altera DE2-70 board through dSPACE DS1103 board using by Proportional-Integral (PI) controller. The dual-input converter circuit model specification with output power at 200 W, input voltages that range from 10 to 60 V, and operating with dual switching frequencies of 50 kHz and 100 kHz is simulated to validate the designed parameters. Design guidelines, simulation and experimental results are presented. The results show that the proposed two-phase DC/DC converter with ZVS technique achieves 94% efficiency for all ranges of loads compared with the multiphase hard-switching. The total power losses across the power switches are reduced by approximately 37% in the proposed converter. Thus, the proposed converter circuit model offers advantages on input current stress and switching loss reductions. The proposed circuit configuration can be used in a standalone hybrid energy system under unregulated DC input voltages. However the major disadvantages of resonant circuit are increased peak current and voltage stress and not suitable for variable frequency operation

SIDO coupled inductor-based high voltage conversion ratio DC–DC converter with three operations

Abstract Here, a single‐input, dual output (SIDO) coupled inductor‐based high voltage conversion ratio DC–DC converter is proposed. The proposed converter has the capability of operating as a SIDO converter in a way that the terminal of the input voltage source is exchangeable among the three ports. Therefore, there are three different operation modes for the proposed converter. The voltage conversion ratios of the high voltage ports over the low voltage port can be improved by increasing the turn ratio of the coupled inductors. The main advantage of the proposed converter is achieving high voltage gains with lower number of components for the whole range of duty cycles comparing to the conventional multi‐port high voltage gain converters. Moreover, two output voltages of the proposed converter can be simultaneously regulated on different constant levels with a good precision. In this study, the voltage conversion ratios, the inductors’ average currents, the voltage and current stress on the switches are calculated theoretically. Finally, an experimental prototype of 30 V input and 410, 260 V outputs with the power 510 W is implemented and the results are verifying the theoretical ones

High-efficiency LED driver without electrolytic capacitor for street lighting

High-Brightness Light Emitting Diodes (HB-LEDs) are considered as a remarkable lighting device due to their high reliability, chromatic variety and increasing efficiency. As a consequence, a high number of solutions for supplying LED strings are coming out. One-stage solutions are cost-effective, but their efficiency is low as they have to fulfill several purposes with only one converter: Power Factor Correction (PFC), galvanic isolation (in some cases) and current regulation. Two-stage and three-stage solutions have higher efficiency as each stage is optimized for just one or two tasks and they are the preferred option when supplying several strings at the same time. Nevertheless, due to their higher cost in comparison to one-stage solutions, they are used when high-efficiency, high-performance and the possibility of supplying several strings are the main concerns. Besides, they are also used when high reliability is needed and electrolytic capacitors cannot be used. In this paper, a three-stage solution and its complete design guideline for LED-based applications is proposed. PFC is achieved by a Boost converter while the galvanic isolation is provided by an Electronic Transformer (second stage). The third stages (one for each LED string) are designed following the TIBuck schematic, but taking advantage of the load characteristics (i.e., the high value of the LED string knee voltage, approximately equal to half the string nominal voltage). Besides, a variation of the analog driving technique is also proposed. Experimental results obtained with a 160-W prototype show an efficiency as high as 93% for the whole topology and 95% for the cascade connection of the second and third stage

Development of Multiport Single Stage Bidirectional Converter for Photovoltaic and Energy Storage Integration

The energy market is on the verge of a paradigm shift as the emergence of renewable energy sources over traditional fossil fuel based energy supply has started to become cost competitive and viable. Unfortunately, most of the attractive renewable sources come with inherent challenges such as: intermittency and unreliability. This is problematic for today\u27s stable, day ahead market based power system. Fortunately, it is well established that energy storage devices can compensate for renewable sources shortcomings. This makes the integration of energy storage with the renewable energy sources, one of the biggest challenges of modern distributed generation solution. This work discusses, the current state of the art of power conversion systems that integrate photovoltaic and battery energy storage systems. It is established that the control of bidirectional power flow to the energy storage device can be improved by optimizing its modulation and control. Traditional multistage conversion systems offers the required power delivery options, but suffers from a rigid power management system, reduced efficiency and increased cost. To solve this problem, a novel three port converter was developed which allows bidirectional power flow between the battery and the load, and unidirectional power flow from the photovoltaic port. The individual two-port portions of the three port converter were optimized in terms of modulation scheme. This leads to optimization of the proposed converter, for all possible power flow modes. In the second stage of the project, the three port converter was improved both in terms of cost and efficiency by proposing an improved topology. The improved three port converter has reduced functionality but is a perfect fit for the targeted microinverter application. The overall control system was designed to achieve improved reference tracking for power management and output AC voltage control. The bidirectional converter and both the proposed three port converters were analyzed theoretically. Finally, experimental prototypes were built to verify their performance

Pregled AC-DC i DC-DC pretvarača za primjene u LED rasvjeti

High-Brightness Light Emitting Diodes (HB-LEDs) are considered the future trend in lighting not only due to their high efficiency and high reliability, but also due to their other outstanding characteristics: chromatic variety, shock and vibration resistance, etc. Nevertheless, they need the development of new power supplies especially designed for boosting and taking advantage of their aforementioned characteristics. Besides, their behaviour is completely different from the rest of lighting devices and, consequently, it should be also taken into account in the design of the converters used to drive them. As a result, many well-known topologies have been optimized or redesigned in order to be used in LED–lighting applications and many new topologies have come up in the recent years with the same purpose. In this paper, the main HB-LED characteristics will be explained, highlighting how they influence the design of their power supplies. After, the main topologies will be presented from the simplest to the most complex ones, analysing their advantages and disadvantages.Svjetleće diode s visokom razinom svjetline (HB-LED) smatraju se budućim trendom u rasvjeti zahvaljujući ne samo visokom stupnju efikasnosti i pouzdanosti, nego i njihovim izvanrednim svojstvima: raznolikost boja, otpornost na udarce i vibracije i sl. Ipak, s ciljem potpunog iskorištenja prethodno spomenutih svojstava, potrebno je razviti nove, posebno osmišljene izvore napajanja. Osim toga, ponašanje im se posve razlikuje od ostalih tipova rasvjete što je potrebno uzeti u obzir pri projektiranju pretvarača za njihovo napajanje. Kao posljedica toga, mnoge su poznate topologije pretvarača optimirane ili preoblikovane posebno za primjenu u LED rasvjeti, a zadnjih nekoliko godina mnoge nove su se tek pojavile. U ovom članku objašnjena su osnovna HB-LED svojstva naglašavajući njihov utjecaj na razvoj izvora napajanja. Uz to, prikazane su osnovne topologije, od najjednostavnijih do najsloženijih, ujedno analizirajući prednosti i nedostatke pojedinih

NASA Tech Briefs, November 1993

Topics covered: Advanced Manufacturing; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences

Techniques for the realization of ultra- reliable spaceborne computer Final report

Bibliography and new techniques for use of error correction and redundancy to improve reliability of spaceborne computer