M. E. Schlittler

Analysis and Design of a Single-Stage High-Power-Factor Dimmable Electronic Ballast for Electrodeless Fluorescent Lamp

A methodological study of an electronic ballast for electrodeless fluorescent lamps (EFLs) including design and development issues is presented in this paper. The ballast is intended to feed a 100-W EFL at 250 kHz with dimming feature. The proposed topology is composed of a single-ended primary-inductance converter, used as power-factor (PF)-correction stage, integrated with a resonant half-bridge inverter, used as lamp-power control stage. The integration of both stages is proposed in this paper, in order to reduce the number of active switches, as well as to simplify the required driving and control circuitry for this application. Experimental results demonstrate the feasibility of the proposed solution that achieves 54% lamp-power dimming (46 W). The implemented topology attained very high PF (0.989) and low line-current total harmonic distortion (14.929%), without using electromagnetic interference filter, while the measured efficiency was 87% at nominal lamp power.

A Comparative Performance Investigation of Single-Stage Dimmable Electronic Ballasts for Electrodeless Fluorescent Lamp Applications

This paper presents a comparative investigation, design and development issues about six different single-stage topologies, applied as electronic ballasts, for electrodeless fluorescent lamps. The ballast is intended to feed a 100 W lamp at 250 kHz, with dimming feature. The proposed topologies use different converters for the power factor correction (PFC) stage: Buck-Boost, SEPIC, Zeta, Cúk, Flyback, and Boost. All of them operate in discontinuous conduction mode. A resonant half-bridge inverter is used as lamp power control (PC) stage. The integration of both stages (PFC and PC) is proposed in this paper. In this way, it is possible to reduce the number of active switches, as well as simplify the required driving and control circuitry. Experimental results demonstrate the feasibility of the proposed dimming technique that achieved around 56% lamp power dimming, from 100 W down to 44 W. The implemented topologies attained high average power factor (>0.98), and low line current average total harmonic distortion (<;15.3%). A comparison among all the proposed topologies in terms of power factor, harmonic distortion, efficiency and number of components is presented. Finally, a comparison between an integrated and a nonintegrated SEPIC half-bridge converter is also performed.

Single-stage high-power-factor dimmable lighting system for electrodeless fluorescent lamp

The use of the electrodeless fluorescent lamps has been increasing, because of their features such as lifetime and lumen efficiency, when compared to conventional fluorescent and high pressure sodium lamps. The single-stage high-power-factor electronic ballast for electrodeless fluorescent lamp with dimming feature is presented on this paper. It is obtained by integrating a SEPIC converter with a Half-Bridge asymmetric LCC resonant inverter, which can effectively regulate the lamp power. Experimental results are shown, in order to validate the proposed idea. The implemented topology presented a power factor of about 0.995, a total current harmonic distortion of 9.61% and an efficiency of 86%.

Dimmable high power factor single-stage electronic ballast for electrodeless fluorescent lamps

Dimmable high-power-factor electronic ballast is proposed in this paper. The electronic ballast is intended to feed a 100 W electrodeless fluorescent lamp (EFL) at 250 kHz. The proposed topology consists of a buck-boost converter, as power factor correction (PFC) stage, associated with a resonant halfbridge inverter, used as lamp power control (PC) stage. In this work, the integration of both stages is proposed in order to reduce the number of active switches, as well as to simplify the required driving and control circuitry for this application. The dimming system is employed by the shared switch duty ratio control, the power variation oscillated from 100W to 44W. The implemented topology achieved a high power factor (PF), varying between 0.992 and 0.979, the line current total harmonic distortion (THD) varied from 10.016% to 6.78%, while the measured efficiency was around 80%.

Electrodeless fluorescent lamps model operated at high frequency

This paper presents an induction electrodeless fluorescent lamp model for simulation, which employs electric equivalents variables inductor and resistance. Because of the lamp negative impedance feature, it is necessary an electrical equivalent model to perform the lamp behavior in simulations. The induction lamp may be represented by an equivalent inductor in parallel with an equivalent resistance. In this paper the resistance uses exponential and the inductance polynomial fitting. The model was implemented in OrCAD/PSpice. Simulation results and experimental data are presented to verify the model feasibility and accuracy.

Analysis and design methodology of a self-oscillating system based on integrated sepic half-bridge for LED lightning applications

This paper presents an analysis and design of an integrated self-oscillating power factor correction (PFC) light emitting diode (LED) driver. The PFC is based on a Single Ended Primary Inductance Converter (SEPIC) operating under Discontinuous Conduction Mode (DCM). This converter was chosen because of its low input current distortion characteristic making possible reducing, or eliminating, the electromagnetic interference (EMI) filter. The LED is supplied by asymmetrical Half-Bridge resonant converter (HB) with isolated LLC filter. It is used the leakage inductance of the transformer and the magnetizing inductance in the LLC filter voltage gain, so as to reduce the volume. The integration of these converters is performed in order to reduce the number of components, drivers and consequently the volume and cost of the circuit. A self-oscillating driver circuit is used avoiding the use of integrated circuits. Design and experimental results are presented to demonstrate the feasibility of the proposed LED driver.

Cost comparison between energy consumption and lifetime depreciation for different compact fluorescent lamps starting scenarios

This paper presents an analysis of the benefit-cost ratio of turning off or not a fluorescent lamp in small time intervals, based on the relation between energy consumption and lamp lifetime depreciation. Thus, this paper analyzes compact fluorescent lamp ignition characteristics considering factors such as: electrical performance, lifetime depreciation, power consumption and the relationship between electrical energy cost and lamp lifetime reduction by switching it on/off. The experimental results show the equivalence between the lamp lifetime depreciation and electrical energy cost to keep it on when it is activated for a certain cycled time period.

Analysis and design of a high-power-factor single-stage buck-boost half-bridge electronic ballast for electrodeless fluorescent lamps

In this paper a methodological study of an electronic ballast including design and development issues is presented. The ballast is intended to feed a 100 W electrodeless fluorescent lamp at 250 kHz. The proposed topology consists of a buck-boost converter, as power factor correction (PFC) stage, integrated with a resonant half-bridge inverter, used as lamp power control (PC) stage. The integration of both stages is proposed, in this work, in order to reduce the number of active switches, as well as to simplify the required driving and control circuitry for this application. The implemented topology achieved a high power factor (0.994) and a line current total harmonic distortion (THD) of 8.016%, while the measured efficiency was 85%.

Low-frequency burst modulation applied to single-stage SEPIC half-bridge topology to feed an electrodeless fluorescent lamp with dimming capability

This paper presents the design and development of an electronic ballast for electrodeless fluorescent lamps operating at 250 kHz. In this system, a dimming control based on a low-frequency modulated PWM signal is proposed. The topology is composed of a Single-Ended Primary-Inductance Converter (SEPIC), used as power factor correction stage, integrated with a resonant half-bridge inverter, used as the lamp power control stage. The integration of both stages is proposed in this paper, in order to reduce the number of active switches, as well as to simplify the required driving and control circuit for this application. Experimental results demonstrate the feasibility of the proposed solution that achieves 74% lamp power dimming (from 100 W down to 26 W). The implemented topology achieved a high power factor (0.99) with efficiency around 86%.

Analysis of losses in the core of an electrodeless fluorescent lamp

An investigation of magnetic core losses of an electrodeless fluorescent lamp is presented in this paper. These losses can be divided into two different kinds: static, which is related to hysteresis effects, and dynamical, associated to parasitic effects. Experimental results (at 25° C) demonstrate that the total losses, in nominal condition point, are approximately 3.18 W, what represent 3.18% of the power supplied to the lamp. In this same point, the static losses are approximately 1.31 W and the dynamic losses about 1.87 W. Based on this, the static losses represent about 41% of total loss related to the magnetic core while dynamical losses represents 59% of total loss.