基于BTS629的自动调光装置的设计实现

为了实现自动调光,简要分析BTS629电路,并采用脉宽调制技术(PWM)对照明灯具及LED的功率进行连续控制以实现自动调光的工作原理.应用该IC芯片和光敏电阻设计了能够实现灯光自动调节的电路,并通过实测光敏电阻参数给出调光比较电位设计的方法.该装置可广泛应用于建筑、街道、汽车等照明应用场合,节能效果显著.     

基于档位智能控制的城市节能照明调光系统

传统城市节能照明调光系统无法实时预测交通车流量,导致城市电能消耗量仍然较大。为此,设计基于档位智能控制模型的城市节能照明调光系统。设计城市节能照明调光系统硬件电路,并通过CC2530最小系统、控制器等外围电路完成系统硬件设计。在系统软件部分,采用档位智能控制模型预测车流量,调节城市节能照明,实现基于档位智能控制模型的城市节能照明调光系统设计。实验结果表明,文中研究的基于档位智能控制模型的城市节能照明调光系统有效减少了城市电能消耗,并降低了照明调节时长,具备实际应用意义。     

基于C8051F350冷阴极荧光观片仪调光系统设计

提出一种基于单片机C8051F350的冷阴极荧光灯（CCFL）观片仪的全自动调光系统,当环境光强发生变化后自动调节观片仪背景照明光源的亮度,使观片仪亮度与环境光强比值达到最佳,系统闲置时,自动进入节能状态,大大提高了观片仪的使用寿命。实验表明该系统很好地实现了观片仪亮度动态调节,具有功耗低、稳定性好等特点。     

基于RT8482的大功率LED驱动电路设计

根据发光二极管的V-I特性,设计了一款基于RT8482芯片的升压恒流大功率LED驱动电路,其输出电压自适应。该电路主要包括输入电源反接保护单元、LED升压恒流驱动单元、PWM数字调光与变阻模拟调光单元、扩流输出单元等,电路同时还具有过压保护、过流保护等功能。测试结果及实际使用表明：该电路在12V输入电压下驱动84w大功率白色LED灯珠阵列时输出电流恒定,其效率可达89．16％,且亮度调节范围宽、精度高,适用于通用与景观照明、汽车照明、室内装饰及电子设备背光等大功率LED照明应用领域。     

无汞平面荧光灯数字调光电路的设计与实现

对无汞平面荧光灯的调光方法进行了分析与研究,实验结果表明,采用脉冲密度调制的数字调光方式不仅可以实现大范围的亮度调节,而且可以降低电路设计的成本和难度。依据上述调光方法,设计并制作了一种基于12寸无汞平面荧光灯的调光电路,试验证明,本文所设计的电路不仅能够降低电路成本,同时能够实现100％～10％宽范围的亮度输出。     

基于单片机的LED自适应调光系统

随着社会的发展人们对照明的要求越来越高,照明越来越普遍化、多样化、耗能化,能源缺乏问题也随之成为社会关注的焦点,LED作为一种新型光源,具有高效节能、绿色环保、使用寿命长等优点,代表着未来照明技术的发展方向。本设计是一种基于单片机STC12C5A60S2的LED自适应调光系统,通过光敏传感器感知外界光强,单片机系统依据此信号以PWM控制方式联合大功率LED驱动芯片ULN2003实现LED灯亮度调节的设计,从而实现光线强度的自动调节,以达到节能的目的。     

基于智能调光的光纤导光照明系统设计

为了更好地利用太阳能资源,提出一种基于智能调光的光纤导光照明系统设计方案。通过对集光器进行优化设计、采用两级定位跟踪模式来提高太阳自动跟踪器的跟踪精度等措施,系统能最大程度地将太阳光导入到光纤以提高系统的光利用率;同时,通过提高跟踪器的跟踪稳定性和增设智能调光功能等措施,使之能克服天气多变、跟踪抖动等因素所导致的光强波动问题,系统的光强稳定度得到了提高。实验测试表明,系统可以获得较好的照明品质,具有一定的应用推广价值。     

电流调光模式对LED液晶模组光学性能的影响

对LED液晶模组,采用模拟调光ADIM和数字调光PWMDIM两种电流控制模式,对比测试了模组的亮度、CIE色坐标、LED焊脚温度数据.实验数据表明,相同整机系统下,平均电流相同时模拟调光比数字调光亮度高、LED芯片温度低.随着平均电流的减小,数字调光的亮度下降幅度比模拟调光明显.数字调光模式CIE y坐标变化比模拟调光小,但x坐标差异不大.通过对以上两种模式下光谱图中RGB各波段的光强变化比以及主波长情况进行分析,认为半导体材料温度变化引起的能带差异以及电光转换效率不同是主要原因.     

基于NCP3065的LED升压驱动电路设计

高效稳定的恒流驱动电路是LED照明工程设计的关键之一。应用新型驱动器件NCP3065设计了一款LED升压恒流驱动电路。介绍了电路的工作原理和元件参数的详细计算过程。所设计电路包含DC-DC升压驱动部分和PWM调光部分,可以驱动5个1 W串联的LED,驱动电压达16 V,电流达350 mA。实测结果表明,电路整体效率高达87.5%,并且具有调光线性度好,性能稳定、可靠等优点,适用于各种大功率LED的照明应用。     

基于LM3402的LED调光电路设计

为提高LED照明电路的使用性能和适用范围,提出了一种基于恒流驱动电路LM3402的调光电路控制系统.由1个LM3402电路驱动一串高亮度白光二极管,根据设定的亮度需求,微处理器P891.PC932通过脉宽调制(PW M)进行调节.实践证明:该系统能够满足多种场合照明的各项要求.工作德定可靠,在同等照度下功耗较白炽灯降低90%以上.     

Dimmable electronic ballasts by variable power density modulation technique

Dimming can be accomplished commonly by switching frequency and pulse density modulation techniques and a variable inductor. In this study, a variable power density modulation (VPDM) control technique is proposed for dimming applications. A fluorescent lamp is operated in several states to meet the desired lamp power in a modulation period. The proposed technique has the same advantages of magnetic dimming topologies have. In addition, a unique and flexible control technique can be achieved. A prototype dimmable electronic ballast is built and experiments related to it have been conducted. As a result, a 36WT8 fluorescent lamp can be driven for a desired lamp power from several alternatives without modulating the switching frequency.     

带调光功能的RCC电路分析

RCC电路即自激式反激变换器,具有电路简单、成本低廉等优点,常用于小功率开关电源中。如今随着LED照明的快速发展,RCC电路也被广泛应用于LED照明的驱动电源设计中。但很多LED照明应用要求LED灯具有可调光的功能,而普通的RCC电路无法与调光器兼容,本文研究如何在RCC电路中加入可与调光器兼容的电路,并对其工作原理进行分析。     

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.     

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.     

A Novel Discrete Dimming Ballast for Linear Fluorescent Lamps

A novel discrete dimming ballast for linear fluorescent lamps is proposed in this paper. A proposed dimming control circuit is combined with a ballast module for multiple lamps to realize control of three discrete lighting levels. Compared with conventional step dimming or on– off control methods, the proposed discrete dimming method has the following advantages: 1) digital signal is generated by the dimming control circuit to control the lamps' turn- on and -off, which makes the system more reliable and integrated; 2) the proposed discrete dimming system replaces relays, which are necessary in conventional lamp on–off control, and therefore decreases the system cost; 3) the proposed dimming ballast can be installed by keeping the original wiring system. This makes the upgrading of a lighting system more effective and efficient; 4) the dimming control circuit also provides a good isolation for operating the low-voltage wall switches by hand safely. Both theoretical, simulation, and experimental results are in good agreement.      

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.     

Comparative Analysis and Experiments of Resonant Tanks for Magnetically Controlled Electronic Ballasts

This paper presents a comparative analysis and experiments of resonant tanks for magnetically controlled electronic ballasts, focusing on their behavior and performance when driving hot cathode fluorescent lamps. Four different resonant tanks are analyzed: LC, LCC, capacitive impedance inverter, and CLL. The analysis is performed using a 36-W fluorescent lamp, which has been previously tested and modeled experimentally. The lamp model is used to derive the dimming characteristics of the different resonant tanks when using the resonant inductance as a control parameter. Analysis and experiments showed that instabilities appear when the lamp power is decreased below a minimum value, which effectively limits the dimming range of the ballast. Nevertheless, the proposed control method can be used to control lamp power in an adequate range provided that the resonant tank should be selected and designed properly.      

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.     

无汞平面光源区域调光方法的设计与实现

为了提高无汞平面光源(FFL)的发光效率和避免放电收缩,设计并制作了一种新型的具有弧形电极结构的无汞平面光源,该结构光源在单极性脉冲作用下具有高亮度、高发光效率以及高工作余度等特性;另外,设计了一种可实现区域调光的电极结构,基于该结构光源,提出了一种调光方法及调光电路;最后,完成了基于81 cm(32 in)无汞平面光...     

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.