Dimming self-oscillating ballast by variable inductor

A simple new dimming technique for self-oscillating electronic ballasts based on a variable inductance is introduced. The variable inductor is controlled by DC current. The goal is to keep the resonant condition during dimming without utilising any IC or complex control circuits. Dimming is successfully accomplished and theoretical and experimental results are presented on self-oscillated current fed push pull electronic ballast.     

Charge pump power-factor-correction dimming electronic ballast

A voltage-source charge pump power-factor correction (CPPFC) continuous dimming electronic ballast is proposed in this paper. The basic charge pump PFC principle is presented, and its unity power factor condition is then reviewed. Constant lamp power control and crest factor correction technique in dimming mode operation are then discussed. A continuous dimming controller with average lamp current control and duty-cycle modulation is developed so that the lamp is able to operate in constant power and low crest factor from 20% to 100% dimming level. The developed dimming electronic ballast has features of higher than 0.99 power factor, low crest factor, and low-DC-bus voltage     

A novel single-stage constant-wattage high-power-factor electronicballast

A novel single-stage high-power-factor electronic ballast is presented in this paper. The ballast is obtained from the integration of a buck-boost converter and a half-bridge LC resonant inverter. The ballast features lamp power regulation against line voltage fluctuations together with high power factor and dimming capability. The steady-state analysis of the ballast is performed and a low-frequency model of the input stage is derived. A design example, including closed-loop circuitry, is also presented. Finally, some experimental results from a laboratory prototype are shown     

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.     

Single-stage electronic ballast with dimming feature and unitypower factor

Analysis, design, and practical consideration of a single-stage electronic ballast with dimming feature and unity power factor are presented in this paper. The proposed single-stage ballast is the combination of a boost converter and a half-bridge series-resonant parallel-loaded inverter. The boost semistage working in the discontinuous conduction mode functions as a power factor corrector and the inverter semistage operated above resonance are employed to ballast the lamp. Replacing the lamp with the plasma model, analysis of the ballast is fulfilled. The dimming feature is carried out by pulse-width modulation (PWM) and variable-frequency controls simultaneously. The proposed single-stage ballast is suitable for applications with moderate power level and low-line voltage while requiring a high-output voltage. It can save a controller, an active switch and its driver, reduce size, and possibly increase system reliability while requiring two additional diodes over a conventional two-stage system. A prototype was implemented to verify the theoretical discussion. The hardware measurements have shown that the desired performance can be achieved feasibly     

High-power-factor electronic ballast operating in criticalconduction mode

A high-power factor (HPF) electronic ballast, which exhibits low switching losses, is presented in this paper. The proposed topology is based on a single power-processing stage, which provides high-frequency voltage to fluorescent lamps and HPF to the utility line. The lamps are driven by a self-oscillating LC parallel resonant power converter of great simplicity and attendant low cost and increased reliability. HPF is achieved by using a nonconventional boost power converter operating in critical conduction mode. Theoretical analysis and experimental results for two 40-W fluorescent lamps operating at 50 kHz from a 127-V utility line have been obtained, which demonstrate the high efficiency and HPF of this electronic ballast     

Design and analysis of an IC-less self-oscillating series resonant inverter for dimmable electronic ballasts

This paper presents a low-cost solution of 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 resonant inductor in the resonant tank to control the operating point of the saturable transformers for driving the switches in the inverter. The overall implementation does not require any integrated circuit. A 17-W prototype has been built and studied. Theoretical predictions have been verified with experimental results. The lamp can be dimmed down to 10% of the full power.     

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.     

Single-stage electronic ballast with high-power factor

This article proposes a single-stage electronic ballast circuit with high-power factor. The proposed circuit was derived by sharing the switches of the power factor correction (PFC) and the half-bridge LCC resonant inverter. This integration of switches forms the proposed single-stage electronic ballast, which provides an almost unity power factor and a ripple-free input current by using a coupled inductor without increasing the voltage stress. In addition, it realises zero-voltage-switching (ZVS) by employing the self-oscillation technique. The saturable transformer constituting the self-oscillating drive limits the lamp current and dominates the switching frequency of the ballast. Therefore, the proposed single-stage ballast has the advantage of high-power factor, high efficiency, low cost and high reliability. Steady-state analysis of the PFC and the half-bridge LCC resonant inverter are described. The results of experiments performed using a 30 W fluorescent lamp are also presented to confirm the performance of the proposed ballast.     

An analysis into the dimming control and characteristic of discharge lamps

This paper provides some qualitative insights into, and a quantitative analysis of, the interrelationship between the ballast circuit parameters and the physical processes inside the lamp arc under dimming conditions. Qualitative explanation is supported by experimental observations on the dimming characteristics of fluorescent and high-intensity-discharge (HID) lamps. This understanding enables engineers to choose the right combination of dimming technique and electronic ballast topology for different types of discharge lamps. Verified by experiments, the fundamental approximation technique is used to characterize the frequency-control and voltage-control dimming technique for series-loaded and parallel-load resonant circuits.     

A single-stage electronic ballast with high power factor

A single stage electronic ballast with high power factor (HPF) is proposed in this letter. The single-phase boost-type rectifier provides HPF. A saturable transformer constituting the self-oscillating drive limits the lamp current and dominates the switching frequency of the ballast. Experimental results obtained on a 40 W fluorescent lamp are discussed     

An electronic ballast with wide dimming range, high PF, and low EMI

The authors describe an electronic ballast design with the capability of low radiated and conducted EMI over a wide dimming range. It overcomes some limitations of traditional electronic ballasts that use frequency variation for dimming control. The proposed design allows soft switching of the ballast from full-power operation down to less than 10% power. Low-cost and low-voltage power metal oxide semiconductor field effect transmitters (MOSFETs) can be used in the proposed dimmable electronic ballast. The design approach is described and implemented successfully in a 2×36 W fluorescent lamp system     

Off-line applications with single-stage converters

Offline applications with single-stage power converters (SSCs) are presented in this paper. The approach used in synthesizing the SSCs is first described, and their applications are then introduced. In addition, viable control strategies for the SSCs are addressed. The developed SSCs can fulfill multifunctions, such as input power factor correction, fast output regulation and lamp ballasting, and possess the merits of compact size, simple driver design and high reliability. Prototypes of SSCs, applied to an electronic dimming ballast and a DC regulator, are built which show high feasibility in such moderate power applications     

Analysis and design of a self-oscillating class E ballast forcompact fluorescent lamps

The Class E inverter is the basis for a low-cost high-frequency ballast, but the control system is more complex than the self-oscillating Class D inverter. The added complexity neutralizes any cost savings gained by the single switch inverter. This paper explores a novel self-oscillating Class E ballast from a design perspective. A qualitative analysis shows how this self-oscillating system operates, from startup, through ignition to the steady state. Optimum component values are found from a quantitative analysis of the inverter. This mathematical model is the basis for the design methodology. Analytical results are compared with the physical model     

调光型节能灯电子镇流器专用集成电路概述

分析了电子镇流器第一代到第三代的发展概况及其特点、当今世界上调光型节能灯电子镇流器的一些流行做法和一些相关电器,并且就调光型节以有灯电子镇流器专用控制ＩＣ举出实例。     

Analysis of the self-oscillating series resonant inverter forelectronic ballasts

In this paper, we examine the self-oscillating series resonant inverter for electronic ballast applications from a system point of view. By considering the discharge lamp as a linear resistor in steady state, we derive a time-domain closed-form expression of the circuit state variables. Importantly, we observe that the self-oscillating series resonant inverter with lamp loads can be naturally modeled as a relay system. Based on this formulation, the self-oscillating frequencies of the inverter for variable lamp impedance conditions are found via the Tsypkin's locus. The stability of the self-oscillating frequencies is determined in a sampled-data system framework     

High-efficiency low-stress electronic dimming ballast for multiplefluorescent lamps

An electronic dimming ballast with a lead-lag tank operation (LLTO) having the properties of high efficiency and low stress is introduced in this paper. The ballast is configured with a voltage-fed half-bridge series-resonant parallel-loaded inverter (SRPLI) acting as a lamp driver. It is loaded with resonant tanks which are designed and operated to be capacitive and inductive to theoretically achieve both zero-voltage switching (ZVS) and zero current switching (ZCS) and to eliminate the reactive current circulating through the switches, resulting in low switching and conduction losses. Moreover, the merit of a successive lamp ignition can be attained with the proposed operation scheme so that current stress imposed on the switches can be reduced. With the plasma model of fluorescent lamps, the analysis, operating principle, and dimming control strategy of the electronic ballast are described in detail. On the other hand, the limitations of the proposed scheme are pointed out. Computer simulation results and experimental measurements are used to verify the theoretical prediction and analytical discussion     

Analysis of the class E amplifier used as electronic ballast with dimming capability for photovoltaic applications

The analysis and design of a dimmable electronic ballast based on the class E amplifier and fed from solar cells with 12V backup batteries is described. The class E amplifier uses a capacitive impedance inverter as resonant tank and one diode antiparallel with the switch; these elements allow implementation of a dimming feature for the ballast and ignition of the lamp while maintaining zero voltage commutations in the switch. The designed electronic ballast drives a 21W lamp and operates at a switching frequency of 370kHz. Dimming is implemented using an SG3524 in a voltage-controlled oscillator fashion.     

基于IR21592型控制器的调光电子镇流器的原理与设计

介绍IR21592型调光镇流器控制器的特点,详细阐述基于IR21592的36 W荧光灯调光电子镇流器电路的工作原理与设计.     

数字式荧光灯电子镇流器的研究与设计

荧光灯由于其复杂的启动过程和时序控制要求,传统的模拟控制实现往往显得麻烦且复杂.介绍了一种基于数字控制的通用化荧光灯电子镇流器,它以MC56F8013 DSP作为控制核心,采用Boost电路进行功率因素校正.通过变频控制,实现了荧光灯预热,高压启动与调光功能.与传统模拟电子镇流器相比,该电子镇流器结构简单,控制灵活并易...