Although savannas are fire-adapted ecosystems, prescribing fire for biodiversity conservation remains controversial at least in some regions where occur. Faced with uncertainty, many decision makers and even scientists still reluctant to prescribe purposes fire-prone invoking the precautionary principle. Knowledge gaps on ideal regime, such as how when burn, especially fear of losses, among main arguments against management applied remnants native savanna vegetation. To inform this debate,...

This paper presents a quadratic boost converter using single quasi-resonant network to reach soft commutation. A resonant inductor, capacitor, and an auxiliary switch form the main operates in zero-current-switching way. complete analysis of this is presented. According simulation experimental results, provides larger conversion ratio than that provided by conventional (for given duty D), optimum performance, which with soft-switch commutation network.

High switching frequency associated with soft commutation techniques is a new trend in converters. Following this trend, the authors present buck pulsewidth modulation converter, where DC voltage conversion ratio has quadratic dependence on duty cycle, providing large step-down. By introducing two resonant networks, attained, highly efficient operating conditions for wide load range at high frequency. Contrary to most of converters that apply soft-switching techniques, switches presented are...

In recent years, light emitting diodes (LEDs) have become a viable alternative to conventional sources. The LEDs are now approaching performance levels that make them attractive for use in several illumination applications. One of the main advantages is their very long life it also related directly with maintenance LED current, preventing device overheating. To contribute LEDs, same ones need efficient drivers optimized control circuitry. focus this paper improve driver characteristics using...

This paper presents an improved regenerative soft turn-on and turn-off snubber applied to a boost pulsewidth-modulated (PWM) converter. The soft-single-switched converter proposed, which has only single active switch, is able operate with switching in PWM way without high voltage current stresses. achieved by using auxiliary inductor, magnetically coupled the main inductor of In order illustrate operating principle this new converter, detailed study, including simulations as well...

The authors consider a family of DC-to-DC power converters using the lossless commutation pulse-width-modulation (PWM) source feeding resonant disconnecting circuit cell with cycle interruption (LC-PWM-SF-RDC) to overcome problems present in quasi-resonant (QRCs) and QRCs-PWM. most important property this devices is ability regulate output voltage by PWM, constant operating frequency, without load limitation, sacrificing commutation. principle design-oriented analysis, characteristics,...

Abstract The conversion of natural habitats into anthropogenic uses is a key driver global biodiversity loss, but effects can vary among taxa and diversity metrics. This has important implications for the use bioindicators in land management. We evaluated local‐scale responses multiple faunal to land‐use change Brazilian Cerrado measuring different aspects (taxonomic functional) levels (alpha beta) diversity. compared ant, dung beetle bird assemblages inhabiting remnants habitat (savanna...

High-switching frequency associated with soft commutation techniques is a trend in switching converters. Following this trend, buck pulsewidth modulation (PWM) converter presented. The DC voltage conversion ratio of has quadratic dependence on duty cycle, providing large stepdown. This new PWM soft-single-switched converter, having only single active switch, provides high efficient operating condition for wide load range at high-switching frequency. In order to illustrate the principle...

This paper presents a PWM boost power converter, where the DC voltage conversion ratio has quadratic dependence on duty cycle, providing large step up (from 24 V to 160 V). By introducing two resonant networks, soft switching is achieved, highly efficient operating conditions for wide load range at high frequencies.

This digests deals with the study of a stand-alone photovoltaic system, which is able to extract maximum power from array for all solar intensity conditions and provide output voltage regulation. The proposed system consists DC-DC converter in combination battery energy storage simple structure. Operating principle control strategy are described. Digital simulation included, supporting validity concept.

This paper presents a PEM fuel cell dynamic modeling, to be employed with electronic circuit simulator software - PSIM. Simulations of the proposed model for fuel-cell, supplying step-up DC-DC converter are presented. Comparisons existing models also made. Practical results presented in this Ballard 1.2kW Nexa Power Module theoretical-experimental comparisons.

This paper presents a high power factor electronic ballast used to startup fluorescent lamps employing single stage and single-switch. topology was obtained combining of Boost converter new inverter with coupled inductors. The use active switch reduces the number components in control circuits. equations for designing proposed reactor choosing semiconductor devices are presented. A prototype operating at 50kHz built 40-W lamps.

This paper is an improved version of a previous study that described boost pulse-width-modulated (PWM) soft-single-switched power converter, which, having only single active switch, able to operate with soft switching in PWM way without high voltage and current stresses. In addition, such converter can work at high-switching frequencies for wide load range. order illustrate the operating principles this detailed study, including simulations experimental tests, carried out. The validity...

A novel soft-commutation cell capable of providing zero current switching (ZCS) operation keeping the main switch equal to load is presented. Substituting typical pulse width modulation found in classic power converter structures by presented ZCS and taking account invariance principle, a new family could be achieved it also here. The properties this are included. theoretical approach for design proposed applied DC–DC buck corroborated experimental results with an 800 W laboratory prototype.

This paper presents a boost converter with nondissipative snubber which provides soft switching operation. approach allows the main switch to work in ZVS way and auxiliary ZCS way. The is composed by two capacitors (resonant capacitors), one inductor inductor), (auxiliary switch) diodes, series other switch. complete operating principle, relevant equations, simulation results experimental are presented.

Usually, a set of resistors is taken to be load for DC-DC converter in "burn-in" evaluation. As consequence, the required energy test dissipated. This paper proposes boost operating without losses commutation used as an active implement tests which returned equipment capacitor instead returning AC system feed. So, consumption during reduced. Certainly, economical advantages reduction will reflected final cost under test. It simple structure with control strategy, and at same time allows...

The proposed DC-DC system introduced in this work provides output voltage regulation and control of energy flow between a battery bank the DC bus. A simple structure, composed by converter storage, is able to compensate power fluctuations supply grid provide protection against outages. operates various modes operation, according load needs limitations, suitable for alternative applications. general concept formulated. Operating principle theoretical analysis are described. Digital simulation...

This work presents a comparison between analog and digital (PIC16c73a) control types applied to the boost converter with nondissipative snubber. Both use bang-bang hysteresis current waveshaping technique in order achieve quasi-unity power factor. The presented high factor (0.998), efficiency (92.87%), low harmonic distortion [total of (THDI =2.84% total (THDV) =2.83%]. (0.990), (92.46%), (THDI=5.09% THDV=2.84%).

This work presents the operation and design of an AC-DC boost interleaved power factor correcting preregulator circuit using a nondissipative snubber operating at 100 kHz per cell. By converters, one can obtain overall reduction inductor, together with reduced switching losses. The complete principles, theoretical analysis, relevant equations simulation results are presented. Experimental prototype rated 500 Watts, input AC voltage 150 Vrms and, output 250 Vdc has been obtained in laboratory.

The aim of this paper is to introduce a dc-dc converter that can be used in an online uninterruptible power supply (UPS). proposed provides uninterrupted, reliable and voltage regulation for critical loads, as well factor correction systems. Operating principles, theoretical analysis, control strategy are described. Digital simulation experimental results included, supporting the validity concept.

The paper proposes a current controlled inverter operating in zero voltage switching (ZVS) mode for an induction machine drive. Operation with no stress the DC link bus is achieved. Together soft operation, fixed frequency bang-bang control technique also implemented to allow accurate shaping of sinusoidal currents feed motor. As result, ripple free torque profile steady state operation With it possible operate conventional IGBTs at 40 kHz. A detailed analysis circuit presented. feasibility...

The authors describe a novel half-bridge quasi-resonant converter, which is regulated by pulse-width modulation, in contrast to the frequency modulated converters reported literature. concept of zero-voltage-zero-current switching proposed. It provides commutation under zero current switch inverter leg and voltage other one. operating principle, design-oriented analysis, design procedure, simulations, experimental results are presented. As consequence constant operation, proposed converter...

This paper presents a new family of PWM soft-single-switched power converters which, having only single active switch, are able to operate with soft switching in pulse width modulation way. In addition, such can work under high frequencies for wide range load without great duty cycle limitations. order illustrate the operating principle these converters, detailed study, including simulations and experimental tests is carried out. The validity guaranteed by obtained results.