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     

High-power-factor electronic ballast based on a single powerprocessing stage

A new high-power-factor (HPF) electronic ballast is introduced in this paper. The proposed topology is based on a single power processing stage, and provides a high-frequency voltage to the fluorescent lamps in addition to presenting an HPF to the utility line. The power processing stage is formed by a half-bridge circuit operating above the resonant frequency, thus providing zero-voltage switching. The self-oscillating technique is employed, which increases the converter reliability with great simplicity. HPF is achieved by using a nonconventional boost stage operating in discontinuous conduction mode, which results in a lower DC-bus voltage than that produced by the conventional boost. Theoretical analysis and experimental results have been obtained for two 40-W fluorescent lamps operating at 40-kHz switching frequency and 220-V line voltage     

A novel single-stage high-power-factor electronic ballast with symmetrical topology

This paper proposes a novel single-stage high-power-factor high-efficiency electronic ballast with symmetrical topology for fluorescent lamps. The circuit topology originates from the integration of two half-wave rectifiers with buck-boost power-factor-correction converters and a half-bridge series-resonant parallel-loaded inverter. A high power factor at the input line is assured by operating the buck-boost converters in discontinuous conduction mode. With symmetrical operation and carefully designed circuit parameters, zero-voltage switching on the active power switches of the inverter can be retained to achieve high circuit efficiency. The design equations are derived from the analyzed results based on fundamental approximation, and then an easy-to-use design tool is provided accordingly under considerations of filament heating and ignition. A prototype circuit designed for two T9-40W rapid-start fluorescent lamps is built and tested to verify the analytical predictions. Satisfactory performance is obtained from the experimental results.     

High frequency electronic ballast provides line frequency lampcurrent

Most electronic ballasts for fluorescent lamps provide a sinusoidal lamp current at the switching frequency. The high-frequency current flowing through the lamp can generate significant radiated noise, which is unacceptable in noise-sensitive applications, such as fluorescent lights in airplanes. Using shielded enclosures for the lamps may solve the problem, but it is expensive. A discontinuous conduction mode (DCM) electronic ballast topology is presented which drives the lamp with line frequency current, just like a magnetic ballast. However, compared to a magnetic ballast, its weight is substantially reduced due to operation at 40 kHz switching frequency. The topology also ensures unity power factor at the input and stable lamp operation at the output     

Design and performance of an electronic ballast for high-pressuresodium (HPS) lamps

An electronic ballast for high-pressure sodium (HPS) lamps was designed and evaluated, theoretically and experimentally. The ballast is based on the half-bridge topology and includes a high-voltage ignitor and dimming capability. It was used to drive and examine the high frequency characteristics of a commercial HPS lamp (NAV-T 150 W (SON-T), OSRAM). The experimental results reveal that, for the frequency range of this study (27-75 kHz), the lamp is free of the acoustic resonance problem. It was also found that, for the present experimental conditions, the lamp is purely resistive, and the resistance is practically independent of the power level and operating frequency. The lamp exhibited stable operation over a very large dimming range, down to about 7% of nominal power. The 2.8-kV ignition pulse was found to be sufficient for both cold and hot startup under the proposed operating conditions     

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.     

Balanced Driving System for Multiple Cold-Cathode Fluorescent Lamps

A novel circuit with dual-high-voltage topology to drive cold-cathode fluorescent lamps (CCFLs) for liquid crystal display (LCD) backlight modules is proposed in this paper. In the proposed circuit topology, all the lamps are connected in series to alleviate the influence of parasitic capacitance induced between the lamps and the aluminum backplank. Balance lamp current and uniform light output can be achieved without using any current balancing circuit. The circuit topology is capable of driving arbitrarily even numbers of lamps with same lamp current while achieving significant reduction in size, weight, and cost. The circuit is verified by experimenting on a backlight module with four L-type lamps in a 19-inch LCD. The experimental results demonstrate the effectiveness and feasibility.      

新型高重复率脉冲固体激光电源

本文介绍了一种新颖的高重复率脉冲固体激光电源,并从理论上详细分析了其工作机理,该激光电源具有重复频率高,体积小,噪音低,效率高及调节方便等优点,具有较大的应用价值。     

High-power-factor electronic ballast with constant DC-link voltage

This paper presents a high-power-factor (HPF) electronic ballast based on a single power processing stage with constant DC-link voltage. The switching frequency is controlled to maintain the DC-link voltage and the voltage across the switches constant, independently of changes in the AC-input voltage. This control method assures zero-voltage switching (ZVS) for the specified AC-input-voltage range. Besides, with an appropriate design of the fluorescent lamps' drive circuit, the lamps' power can be kept close to the rated value. The power-factor-correction (PFC) stage is formed by a boost power converter operating in the discontinuous conduction mode, which naturally provides HPF to the utility line. The fluorescent lamps are driven by an unmodulated sine-wave current generated from an LC parallel resonant power converter which operates above the resonant frequency to perform ZVS. Theoretical analysis and experimental results are presented for two series-connected 40 W fluorescent lamps operating from 127 V -15% to +10% 60 Hz utility line. The switching frequency is changed from 25 to 45 kHz to maintain the DC-link voltage regulated at 410 V, which leads to a constant output power. The experimental results confirm the high efficiency and HPF of this electronic ballast     

Low Frequency Architecture for Multi-Lamp CCFL Systems With Capacitive Ignition

A low frequency architecture is proposed for driving parallel cold cathode fluorescent lamps (CCFLs) in large screen liquid crystal display (LCD) TV backlighting applications. Key to the architecture is a proposed capacitive coupling approach for aiding lamp ignition. A dc voltage is applied to the lamp electrodes while an ac voltage is applied to an external plate for capacitive coupling. The result is reliable, simultaneous ignition of parallel lamps with a required applied dc voltage near the lamp steady-state operating voltage. The complete system architecture includes a single high voltage converter, a pulse lamp ignition circuit, current control circuits and a single backlight controller. The topology is capable of driving a large number of parallel lamps with independent lamp current regulation, while avoiding ac coupling losses in steady-state operation and achieving significant reduction in reactive components when compared to typical high frequency ac ballast designs. Experimental results are presented for a system of four parallel 250 mm length lamps, demonstrating simultaneous parallel lamp ignition and dc current regulation.     

A high-power-factor electronic ballast using a flyback push-pullintegrated converter

This paper describes a high-power-factor electronic ballast for fluorescent lamps. The converter offers a high power factor and a high-frequency supply to the lamp using a single switch. In spite of its simplicity, an excellent performance concerning load and supply is achieved, ensuring a sinusoidal and in-phase supply current. High power factor is achieved by using a flyback converter operating in discontinuous conduction mode. Operating principle, design equations, component stress, and efficiency are presented. Experimental results have been obtained for one 40-W fluorescent lamp operating at 50-kHz switching frequency and 220-V line voltage     

A Semi-Theoretical Fluorescent Lamp Model for Time-Domain Transient and Steady-State Simulations

Low-pressure discharge lamps obey a set of physical laws that are different from those of high-pressure discharge lamps. In this paper, these differences are addressed. Based on a recently developed HID lamp model frame, a semi-theoretical fluorescent lamp model that can be determined by genetic algorithms and simple electrical measurements is presented. This model does not require any lamp data from lamp manufacturers. Its parameters can be determined from electrical voltage and current measurements of the lamps under AC operation at mains frequency. With the same set of parameters, the model can predict the lamp terminal characteristics accurately under low, medium and high frequency operations. Good simulation results were achieved when the lamp power was reduced to 60% of rated power and when the lamp was operated under step-up and step-down transient processes. Simulation results for different sizes of tubular and compact fluorescent lamps agree well with their experimental results. Particularly, the differences between simulation results and experimental results under rated power are less than 10%. Hence, the proposed model shows a good degree of accuracy: 1) for different types of fluorescent lamps; 2) at different operating frequencies; 3) under different dimming levels; and 4) during step-up and step-down transient processes.     

Contributions to the design and control of LCsCp resonant inverters to drive high-power HPS lamps

This paper presents the design criteria for full-bridge series-parallel (LC_sC_p) resonant inverters suitable for driving high-power high-intensity discharge lamps. By using the properties derived from the transfer functions of the inverter, a soft startup method is proposed. The lamp ignition is carried out maintaining the voltage and current variables below prefixed peak values, with the addition of no extra components to the power stage for this purpose. In steady-state operation, the proposed control minimizes the reactive voltamperes in the resonant tank. Moreover, the variation of the power delivered to the lamp, caused by the lamp aging, is limited in order to fulfil the standard. This design provides cost-effective circuits, simplifying the DC-AC power stage of an electronic ballast. The experimental results are given for high-pressure sodium lamps of the Sylvania SHP250W type     

A new hybrid filter to dampen resonances and compensate harmoniccurrents in industrial power systems with power factor correctionequipment

A new hybrid power filter is presented for three phase industrial power systems which include passive power factor correction equipment (PFC). The hybrid filter damps resonances occurring between line impedances and the PFC. In addition, the hybrid filter topology can be used to compensate harmonic currents. The capacitors of the PFC, which generally cause resonant problems in harmonic distorted networks, can be used for passive filtering by connecting a transformer with a low magnetizing inductance in series hence creating a single harmonic trap. The primary side of the transformer is connected to a low VA-rated three-phase current controlled inverter which builds the active part of the hybrid topology. Simulation results and experimental results are presented verifying the damping and harmonic compensation performance of the proposed topology     

基于SP6641的手持设备电源设计

根据心理测评数据采集手持设备的低功耗要求,采用SP6641设计高效、升压DC／DC转换电源电路。详细介绍电路设计方案和外围电路元件的选择,实现手持设备使用2节普通碱性电池升压供电。这种电源电路具有很低的启动电压、超低静态电流、高效率电压转换的特点,可用于单或双电池供电的手持设备应用。     

Primary-side dimming control driver for cold-cathode fluorescentlamps

A novel primary-side dimming control driver for cold-cathode fluorescent lamps (CCFLs) is investigated theoretically and experimentally. This new topology successfully solves the uneven sensitivity of dimming control, and the problem of uneven illumination in a two-lamp system. In particular, the circuit is simple, has a low component count and is highly efficient     

变频技术在气体放电灯调光中的应用

介绍变频技术在荧光灯、节能灯的电子镇流器电路中的应用,变频调光,以及低功率下如何保持荧光灯阴极高发射效率,防止损害灯管的技术方法。     

An improved “charge pump” electronic ballast with lowTHD and low crest factor

The “charge pump” electronic ballast circuit, which employs a charging capacitor and a high-frequency AC source to implement power factor correction (PFC), has become an attractive topology for ballasting fluorescent lamps. However, the basic “charge pump” electronic ballast circuit has the problems of high total harmonic distortion (THD) of the input current and high crest factor (CF) of the lamp current. This paper analyzes the origin of the problems and proposes a novel solution. With the addition of two small clamping diodes, good input current (PF>0.99, THD<5%) and lamp current (CF<1.6) can be obtained with open-loop control. Experimental results are provided for verification     

An improved charge pump power factor correction electronic ballast

An improved charge pump power factor correction (CPPFC) electronic ballast using the charge pump concept is proposed in this paper. Circuit derivation, principle of operation, and the conditions for achieving unity power factor are discussed. The proposed electronic ballast is implemented and tested with two 40 W fluorescent lamps. It is shown that 84% of overall efficiency and 1.6 of crest factor can be achieved with 200-V line input voltage. The measured line input current harmonics satisfy IEC 1000-3-2 Class C requirements. The lamp power variation range is automatically limited within ±15% for ±10% line input voltage variation without feedback control     

太阳能光伏照明系统概述

分别叙述了太阳能在荧光灯、HID灯、LED灯照明系统中的应用。为提高太阳能光伏照明系统的可靠性,介绍了太阳能光伏照明风光互补系统和太阳能光伏照明光电互补系统。并提出太阳能光伏照明系统中应注意的技术问题。