A. R. Seidel

A practical comparison among high-power-factor electronic ballasts with similar ideas

This paper provides a comparative analysis among four electronic ballast topologies with high power factor, employing the same switch for inverter and power factor correction stage. The analyses done are based on experimental results. A commercial electromagnetic ballast (EMB) is tested to provide a comparison with implemented electronic ballasts. The features of each topology are shown through the discussion of their advantages and disadvantages. The electronic ballasts are made for two 40-W fluorescent lamps at 50-kHz switching frequency and for a 110-V/sub rms/ 60-Hz utility line.

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.

Resonant filter applications in electronic ballast

In this paper an analysis is presented of the resonant filter used in an electronic ballast through the phase angle from the input resonant filter current to the input resonant filter voltage. The proposed analysis allows evaluation of the resonant filter characteristics. The main characteristics that are analyzed are: lamp starting, soft commutation, DC current in the lamp, resonant filter influence in the converters and lamp pre-heating. This work allows a choice of the best filter to employ in an electronic ballast for fluorescent lamps.

Fluorescent lamp model based on the equivalent resistance variation

A circuit model simulating the electrical characteristics of a fluorescent lamp operating at high frequency is proposed. The model is based on exponential approximation that represents the equivalent resistance variation as function of power, constructed by experimental results for several power levels. Simulations and experimental results are presented to verify the feasibility of the model and, moreover, an electronic ballast example using the proposed model is presented to further demonstrate its applications.

Self-oscillating electronic ballast design based on the point of view of control system

This paper presents a design methodology, analysis, and practical considerations of self-oscillating drive circuit for electronic ballasts by considering the self-oscillating electronic ballast as a relay control system. The first section of the paper analyzes the design of resonant elements, the nonlinearity present in the circuit and consideration to apply the methodology proposed. The second section of the paper shows the design of self-oscillating electronic ballast using control tools such as: describing function, extended Nyquist criterion and block diagrams that allows an expression for designing the self-oscillating electronic ballast to be found.

Simple valley-fill self-oscillating electronic ballast with low crest factor using pulse-frequency modulation

This paper presents an alternative to achieve fluorescent lamp current low crest factor, using the valley-fill filter as a passive power-factor-correction method. Pulse frequency modulation is used to reduce lamp current high crest factor. Self-oscillating electronic ballast is employed in order to avoid complex circuitry. The partial smoothing valley-fill DC-link bus voltage is used to control the switching frequency. Crest factor correction is achieved through a low power bipolar transistor, which connects a low power passive circuit parallel within the self-oscillating gate-driver circuit. The switching frequency changes in order to keep the lamp current crest factor lower than 1.7 and a modified valley-fill filter is used to meet IEC61000-3-2 requirements. Simulations and experimental results are presented to demonstrate the simplicity, and feasibility of the proposed system.

An analysis about valley fill filters applied to electronic ballasts

This paper presents a detailed analysis about valley fill filters applied to power factor (PF) correction of electronic ballasts. Comparative results about input current THD are done in this study, verifying if it meets the IEC 61000-3-2 standard requirements, that determines the maximum amplitude of each harmonic component from 2/sup nd/ up to 39/sup th/. Power factor (PF), total harmonic distortion (THD), crest factor (CF), auxiliary circuit losses, and operation principles are also presented.

Constant-Frequency Magnetically Controlled Universal Ballast With SoS Compliance for TL5 Fluorescent Lamps

This paper presents the development of a universal electronic ballast for TL5 lamps. The intent is to efficiently operate the maximum number of TL5 lamps with different power ratings at nominal power, using a resonant variable inductance, provided by a magnetic regulator, while maintaining the switching frequency constant. A microcontroller and additional digital circuitry are used to command a dc-dc buck converter to supply the necessary dc control current to the magnetic regulator and to regulate the switching frequency of the half-bridge resonant inverter that supplies the lamp. The selection of the resonant capacitance is done in order to comply with the SoS limits established for each lamp. Experimental results with lamps ranging from 14 to 49 W, operating with high efficiency and high output, are presented in this paper.

A design method for electronic ballast for fluorescent lamps

This paper presents a new design methodology, analysis, and practical considerations about series parallel resonant filter, LCC, for electronic ballasts employing the self-oscillating driver circuit. Designs equations and graphic methods are presented, obtained by analysis of Fourier series, Tsypkins Locus and stability tests. The lamp high frequency supply is given by the half-bridge converter, and the verification of this approach is guaranteed by simulation and experimental results.

Low cost high-power-factor electronic ballast for compact fluorescent lamps

This paper presents the analysis, design and practical considerations of several low cost high-power-factor ballast for compact fluorescent lamps. The proposed topologies are a combination of a boost converter and a half-bridge parallel resonant converter. The high frequency supply to the lamp is made by a self oscillating half-bridge converter, using integrated circuits IR2151 and IR51HD420. The high-power-factor is guaranteed by using a boost converter operating in discontinuous conduction mode. These topologies have been developed for 20 W compact fluorescent lamps for 110 V, 60 Hz utility line.