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.

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

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.

Self-oscillating dimmable 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.

A Design Methodology for a Self-Oscillating 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.

http://ieeexplore.ieee.org/iel5/8075/22360/01044111.pdf

Resonant filter applications in electronic ballast

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.

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

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

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

This paper presents two simple alternatives of electronic ballast operating in self sustained oscillating mode with dimming capability for fluorescent lamps. A simple modification in the drive circuit allows dimming of the lamp. The describing function method and the extended Nyquist criterion are used in the analysis and the design. Experimental results from two 40 W electronic ballasts are presented to demonstrate the performance and to validate the analysis carried out.

R.K. Pavao

Papers

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

Self-oscillating dimmable electronic ballast