Self-oscillating Electronic Ballast Research Articles

Tubular Fluorescent Lamps Detection Based on the Self-Oscillating Electronic Ballast

In this paper, the detection of T5 tubular fluorescent lamps (FLs) is carried out with a self-oscillating electronic ballast. The developed topology identifies and operates different lamps with their rated powers. A single-ended primary-inductor converter (SEPIC) is used for power factor correction (PFC), with a half-bridge inverter to supply the lamps. The lamps detection is realized by means of an analog electronic circuit. The command of the switches of the PFC and inverter stages is accomplished by the self-oscillating circuit. Experimental results, as well as an analysis of the data referring to compliance with the technical standard NBR 14418 are presented in relation to preheating of the T5 FLs electrodes.

Reconhecimento de Lâmpadas Fluorescentes Empregando o Reator Eletrônico Auto-Oscilante

Neste trabalho é realizado o reconhecimento de lâmpadas fluorescentes tubulares T5 com o reator eletrônico auto-oscilante. A topologia desenvolvida identifica e opera diferentes lâmpadas com sua potência nominal. Um conversor SEPIC é empregado para correção do fator de potência, juntamente com um inversor meia- ponte para alimentar as lâmpadas. A identificação das lâmpadas é realizada com o auxílio de um circuito eletrônico analógico. O circuito de comando auto-oscilante é utilizado para o acionamento dos interruptores dos estágios inversor e de correção do fator de potência. São apresentados resultados experimentais e uma análise dos dados referentes ao atendimento da norma técnica NBR 14418, relativa ao preaquecimento dos eletrodos de lâmpadas fluorescentes T5.

Iterative Method for Analysis of Dimmable Self-oscillating Electronic Ballast Under Bus Voltage Control

This paper presents a predictive method of the self-oscillating electronic ballast (SOEB) behavior under dimming conditions. This work is focused on the bus voltage variation dimming method, where a closed analysis is not possible to carry out without considering the interaction among inverter bus voltage, fluorescent lamp power/resistance nonlinear behavior, and frequency operation of the SOEB. Thus, an iterative method is proposed in order to predict the oscillating frequency related with the fluorescent lamp power under bus voltage variation. Experimental results for a T8 32 W fluorescent lamp are obtained in order to compare simulation results, and verify the feasibility of the proposed method

Comparative Analysis of Self-Oscillating Electronic Ballast Dimming Methods With Power Factor Correction for Fluorescent Lamps

This paper presents a comparative analysis of the performance characteristics among different dimming methods for electronic ballasts using the self-oscillating half-bridge (HB) inverter with a power factor correction (PFC) stage. Initially, a review of common dimming methods presented in the literature is presented, and a general analysis of each dimming method is carried out. Furthermore, the operation of the dimmable self-oscillating electronic ballast with a PFC stage is analyzed in order to evaluate the performance of each different dimming methods used. Finally, a comparison among the different dimming methods implemented with the self-oscillating HB inverter and PFC stage is carried out.

Investigation and Improvement of Self-Oscillating Electronic Ballast for Local Fluorescent Emergency Light

This paper presents an analysis and improvement of self-oscillation electronic ballast for local emergency light. The improvement circuit has been presented by replacing the original BJTs with MOSFETs as a switching device. Also, 555-timer has been used to drive the MOSFETs instead of the ballast feedback in the original circuit. This electronic ballast start and regulate fluorescent lamps by converting a DC supply to high ignition AC voltage by a rectifier circuit with switching frequency in the range of 20 kHz -1MHz. Operation at high frequency has two advantages; an improved efficiency and elimination of flickering in the lamps. The simulation has been done by using PSIM Simulink software and its results have been compared with experimental results. The results shows that by using MOSFETs as a switching device, the Total Harmonic Distortion (THD) has been reduced and the brightness of lamp tube has been increased greatly.

Feedforward Regulation Method for Self-Oscillating Electronic Ballast for Fluorescent Lamps

This paper presents a feedforward fluorescent lamp power regulation method for self-oscillating electronic ballast for different line voltages. The proposed method consists in maintaining the lamp power regulated through the feedforward switching frequency variation using the output resonant filter feature and self-oscillating gate driver circuit. Experimental results demonstrate the feasibility of the proposed solution that allows regulating the lamp power in a wide input voltage range (110 to 220 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> ) with an error of up to 12%.

Analysis and Design of Self-Oscillating Full-Bridge Electronic Ballast for Metal Halide Lamp at 2.65-MHz Operating Frequency

This paper presents the analysis and design of the self-oscillating full-bridge electronic ballast for the metal halide lamp at 2.65-MHz operating frequency. In order to avoid the acoustic-resonance problem of the metal halide lamp and meet the electromagnetic interference limitation by International Electrotechnical Commission (IEC) regulation, the self-oscillating full-bridge electronic ballast is operated at 2.65-MHz radio frequency (RF). However, the effect caused by the gate-to-source capacitor Cgs of the mosfets on the self-oscillating gate-drive network becomes significant to influence the design of the operating frequency at RF. Therefore, the gate-to-source capacitor Cgs of the mosfets is considered to derive the design equation of the magnetizing inductor for the current transformer in the self-oscillating gate-drive network. Finally, based on the prototype circuit of a 35-W self-oscillating full-bridge electronic ballast with constant-lamp-current control and no-lamp-protection scheme at 2.65-MHz operating frequency, the SIMPLIS simulation and experimental results are used to validate the effect from gate-to-source capacitor Cgs, the proposed design equation, and the design criteria.

Analysis and Design Method for High-Frequency Self-Oscillating Electronic Ballasts

In this paper, the analysis and design methodology of a high-frequency self-oscillating (SO) electronic ballast with lamp current control are presented. SO electronic ballasts have two important drawbacks: First, the lamp current varies according to the ac input voltage, causing undesired effects in the lamp brightness, and second, the design method lacks precision at very high frequency operation (greater than 200 kHz) mainly due to the parasitic capacitance. The ballast is modeled by using the descriptive function method and the extended Nyquist criterion; the model of the ballast includes a control circuit and takes into account the high-frequency effect of the MOSFET parasitic capacitance. Finally, experimental results of a 38-W SO electronic ballast prototype with lamp current control for high-intensity discharge lamps are presented to validate the analysis and the proposed methodology. The switching frequency is selected at 2 MHz in order to avoid the acoustic resonance problem.

Novel Single-Stage Self-Oscillating Dimmable Electronic Ballast With High Power Factor Correction

A novel self-oscillating electronic ballast with dimming capability and high power factor correction (PFC) is proposed in this paper. The single-stage electronic ballast integrates a buck-boost PFC stage with a half-bridge LCC series-parallel resonant inverter. The buck-boost semistage operating in discontinuous conduction mode inherently has high PFC. The inverter is dimmable in self-oscillation mode, which is achieved using pulsewidth modulation and variable-frequency controls. The dimming circuit is simple and low cost. The self-sustained oscillation of the dimmable electronic ballast for fluorescent lamps was verified using the dual-input describing function method. A prototype of a 10-W dimmable electronic ballast was implemented to verify the theoretical analysis.

Designing of Protection Circuit for Self-Oscillating Electronic Ballast that Connected Two Wires to Fluorescent Lamp

Designing of Protection Circuit for Self-Oscillating Electronic Ballast that Connected Two Wires to Fluorescent Lamp

A Design Methodology for a Self-Oscillating Electronic Ballast

This paper presents a design methodology and analysis of electronic ballast employing the self-oscillating-command circuit. The self-oscillating electronic ballast is represented as a relay control system in order to determine its parameters using the describing-function method and an extended Nyquist stability criterion. Simulation and experimental results of the electronic ballast supplying a 40-W fluorescent lamp are presented in order to confirm the feasibility of the performed design methodology.

2.65-MHz Self-Oscillating Complementary Electronic Ballast With Constant-Lamp-Current Control for a Metal Halide Lamp

This paper presents the design and implementation of the 2.65-MHz self-oscillating complementary electronic ballast with a constant-lamp-current control for a metal halide lamp. In order to avoid the inherent acoustic-resonance problem of metal halide lamps, the ballast's switching-frequency level was selected to be 2.65 MHz, which satisfies higher magnitudes of maximum electromagnetic interference (EMI) limitation at frequencies of between 2.5 to 3.0 MHz, within the EMI/electromagnetic compatibility frequency range ldquochimney,rdquo for RF lighting systems. With the constant-lamp-current control scheme, the lamp current can be regulated to be less dependent on the input ac voltage. Finally, a 20-W prototype ballast is implemented to demonstrate the ability to avoid the acoustic-resonance and to provide constant levels of lamp current.

2.65-MHz Self-Oscillating Electronic Ballast With Constant-Lamp-Current Control for Metal Halide Lamp

This paper presents the 2.65-MHz self-oscillating electronic ballast with constant-lamp-current control for metal halide (MH) lamps. To avoid the inherent acoustic-resonance problem of MH lamps, the switching frequency is chosen to be above 1MHz. Furthermore, in order to satisfy higher magnitudes of maximum electromagnetic interference limitation at frequencies of between 2.5 to 3.0MHz, the ballast's switching-frequency level was selected to be 2.65MHz, which falls within the frequency range chimney, for radio-frequency lighting systems, such as electrode-less fluorescent lamps. The conventional self-oscillating electronic ballast is disadvantageous because the lamp current varies according to the input voltage. This difference in lamp current causes poor color rendering index for the lamp. In order to solve this issue for the self-oscillating electronic ballast, the constant-lamp-current control circuit is proposed to provide constant lamp current. Finally, a 20W self-oscillating ballast with the proposed constant-lamp-current control for MH lamps is implemented in order to demonstrate the ability to avoid acoustic resonance and to provide constant levels of lamp current

Reator eletrônico auto-oscilante com alto fator de potência para alimentação de quatro lâmpadas fluorescentes independentes

Este artigo descreve um reator eletrônico auto-oscilante, com freqüência de operação fixa, para alimentar quatro lâmpadas fluorescentes independentes, com alto fator de potência. Para a correção do fator de potência foram estudadas várias modificações do filtro valley-fill, existentes na literatura, selecionando uma que atendesse à norma internacional IEC 61000-3-2 quanto à distorção harmônica da corrente de entrada. Para o acionamento dos interruptores foi desenvolvida uma modificação do comando auto-oscilante, inédita na literatura, tornando-o independente da carga. Deste modo, foi montado o protótipo e feitas as aquisições experimentais.

Reator eletrônico auto-oscilante "valley-fill" com correção do fator de crista utilizando modulação em freqüência

Neste artigo, apresenta-se um reator eletrônico auto-oscilante empregando o filtro valley-fill modificado como método de correção do fator de potência, de modo a atender a norma IEC 61000-3-2 Classe C. Para solucionar o problema do alto fator de crista da corrente na lâmpada fluorescente inerente ao filtro "valley-fill", emprega-se um sistema de modulação em freqüência. Um circuito simples e de baixo custo mantém o fator de crista abaixo do limite de 1,7. São utilizadas as características de ganho do filtro ressonante aliadas à possibilidade de controlar a freqüência do circuito de comando auto-oscilante a partir da característica da tensão de barramento do reator.

High Power Factor Self-Oscillating Electronic Ballast to Supply Four Fluorescent Lamps

This paper presents an innovative modification in the conventional self-oscillating driver, in order to supply variable loads. This modification consists of adding an auxiliary output filter supplying a small power resistor, which also includes the primary winding of the self-oscillating transformer. The analysis for self-sustained oscillations is performed by extended Nyquist criterion, which defines the design equations for the ballast component values. A design example is presented, using the proposed circuit in a high power factor electronic ballast supplying four independent lamps. A passive circuit named valley charge pump is used to perform the power factor correction. The ballast supplies four lamps independently, without considerable frequency changes, with an efficiency of 93%, and reaching IEC 61000-3-2 requirements for the input current distortion.

Self-Oscillating Dimmable Electronic Ballast for Fluorescent Lamps

This letter presents a low-cost solution for converting the popularly adopted nondimmable electronic ballast circuit for fluorescent lamps with self-oscillating series resonant inverter into a dimmable one. The dimming function is achieved by increasing the switching frequency of the inverter from the natural frequency of the resonant tank, so that less energy is coupled to the lamp. Control of the switching frequency is based on deriving an adjustable dc current source from the inductor in the resonant tank to control the operating point of the saturable chokes for driving the switches in the inverter. The overall circuit does not require any integrated circuit. A 17-W prototype has been built and tested. Theoretical predictions have been verified with experimental results. The lamp can be dimmed to 10% of the full brightness.

Estudo e Implementação de Controle Secundário em Microrredes CC

Este trabalho visa no estudo de microrredes CC, devido à crescente utilização de fontes alternativas e renováveis de energia capazes de gerar eletricidade em CC. As microrredes podem ser gerenciadas por uma estrutura hierárquica de controle com ênfase no controle secundário, integrando sistemas de geração distribuída e de armazenamento de energia, bem como cargas genéricas. O controle secundário desempenha funções cruciais de compartilhamento de potência/corrente e regulação da tensão CC no barramento da microrrede. Uma questão essencial abordada neste trabalho é a implementação de uma rede de comunicação entre os conversores que compõem a microrrede CC. Desta forma, este estudo propõe uma abordagem distribuída para o compartilhamento de potência/corrente, melhorando a eficiência de distribuição de alocação de potência e operação da microrrede. O estudo também avalia duas topologias, em anel e linha, de redes de comunicação. Como consequência, os resultados obtidos validaram a estratégia de controle secundário proposta para microrredes CC, bem como concluiu-se que a configuração de comunicação em anel demonstrou maior robustez em comparação à topologia em linha. Tais resultados foram obtidos através de simulações computacionais e testes experimentais, os quais incluíram variações de carga, distúrbios e falhas de comunicação.

Projeto do Reator Eletrônico Auto-Oscilante

Neste artigo é apresentada a análise e o projeto do circuito de comando auto-oscilante empregado em reatores eletrônicos. O reator eletrônico autooscilante é representado por um sistema de controle do tipo relé. Para análise e projeto, são utilizados o método da função descritiva e o critério estendido de estabilidade de Nyquist, dos quais obtêm-se as equações de projeto do mesmo. Resultados de simulação e experimentais para um reator eletrônico de 40 W são apresentados para demonstrar sua performance e validar a análise feita.

Self-oscillating dimmable electronic ballast

This paper presents a simple alternative for an electronic ballast operating in self-sustained oscillating mode with dimming capability for fluorescent lamps. A simple modification in one of the gate drivers side circuit allows the lamp to dim without compromising the simplicity, reliability, and low cost which characterize the self-oscillating electronic ballast (SOEB). A qualitative analysis is presented to explain the behavior of the proposed self-oscillating electronic ballast with dimming feature. In addition, the stability and the key equations for the design are derived using the extended Nyquist criterion and describing function method. Experimental results from two 40-W electronic ballasts are presented to demonstrate the performance and to validate the analysis carried out.