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1.
Huang‐Jen Chiu Yu‐Kang Lo Shih‐Jen Cheng Yeong‐Chang Yan Hung‐Chi Lee Kuan‐Hung Wu Chung‐Yi Lin Shao‐Shih Ho Ming‐Hsiang Tseng Fu‐Hsien Huang 《International Journal of Circuit Theory and Applications》2011,39(11):1161-1175
In this paper, we study the feasibility of a single‐stage lighting LED lamp driver with low DC bus voltage. The operating principles and design considerations for the LED lamp driver in this study are analyzed and discussed in detail. A laboratory prototype has been built and tested. Using the prototype, high efficiency, high‐power factor and LED current control were achieved using a wide AC input voltage range from 90 to 270 V. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
2.
Xiaohui Qu Siu‐Chung Wong Chi K. Tse 《International Journal of Circuit Theory and Applications》2012,40(8):759-775
To emit high‐quality LED light, one or a bin of LED lamp(s) is normally driven by a PWM‐controlled constant current source to minimize device variation and achieve accurate brightness control. Powered from offline AC mains, the front‐end power converters should provide a relatively low DC voltage bus for the inputs of post‐end LED current regulators. To match the long lifetime of LEDs, the whole LED driver (ballast) should work as durably as the LEDs. However, the lifetime of the driver is usually limited by the high‐voltage electrolytic charge storage capacitors used in conventional PFC pre‐regulators. In this paper, our previously proposed resonant current‐fed isolated PFC pre‐regulator is extended to operate in discontinuous conduction mode (DCM). It allows the use of the low‐voltage storage capacitors on the transformer secondary, and therefore extends the overall lifetime of the LED lighting system. A detailed procedure for finding the expected lifetime of the low‐voltage electrolytic capacitor is given. As before, the high‐voltage stress on the main switches, which is typical in current‐fed isolated converters, is reduced substantially by taking advantage of the transformer leakage inductance necessary for resonance. Additionally, high efficiency is ensured by the use of dual non‐cascading structures. Steady‐state state‐space averaging analysis is performed for designing the converter in DCM operation. A prototype converter is built to verify performance of the proposed PFC LED pre‐regulator. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
3.
Hongbo Ma Jih‐Sheng Lai Quanyuan Feng Wensong Yu Cong Zheng 《International Journal of Circuit Theory and Applications》2013,41(5):514-534
The AC–DC power supply for LED lighting application requires a long lifetime while maintaining high‐efficiency, high power factor and low cost. However, a typical design uses electrolytic capacitor as storage capacitor, which is not only bulky but also with short life span, thus hampering performance improvement of the entire LED lighting system. In this article, a SEPIC‐derived power factor correction topology is proposed as the first stage for driving multiple lighting LED lamps. Along with a relatively large voltage ripple allowable in a two‐stage design, the proposal of LED lamp driver is able to eliminate the electrolytic capacitor while maintaining high power factor and high efficiency. To further increase the efficiency of LED driver, we introduced and used the twin‐bus buck converter as the second‐stage current regulator with Pulse Width Modulation (PWM) dimming function. The basic operating principle and the deign consideration are discussed in detail. A 50‐W prototype has been built and tested to verify the proposal. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
4.
Kuan‐Hung Wu Huang‐Jen Chiu Yu‐Kang Lo 《International Journal of Circuit Theory and Applications》2014,42(1):96-109
An alternating‐current light‐emitting diode (AC‐LED) driver is implemented between the grid and lamp to eliminate the disadvantages of a directly grid‐tied AC‐LED lamp. In order to highlight the benefits of AC‐LED technology, a single‐stage converter with few components is adopted. A high power‐factor single‐stage bridgeless AC/AC converter is proposed with higher efficiency, greater power factor, less harmonics to pass IEC 61000‐3‐2 class C, and better regulation of output current. The brightness and flicker frequency issues caused by a low‐frequency sinusoidal input are surpassed by the implementation of a high‐frequency square‐wave output current. In addition, the characteristics of the proposed circuit are discussed and analyzed in order to design the AC‐LED driver. Finally, some simulation and experimental results are shown to verify this proposed scheme. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
5.
Huang‐Jen Chiu Shih‐Jen Cheng 《International Journal of Circuit Theory and Applications》2009,37(8):928-940
This paper presents a single‐ended primary inductance power‐factor‐correction converter (SEPIC PFC) for driving multiple lighting LED lamps. With the aid of this converter, high power factor and high efficiency can be achieved by a simple single‐stage circuit with low device stress features. A burst‐mode dimming method is used to regulate the current and brightness of multiple LED lamps. A laboratory prototype is also built and tested. With the prototype, high power factor can remain under universal input voltage operation and individual lamp brightness control. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
6.
Kasi Ramakrishnareddy Ch Shunmugam Porpandiselvi Neti Vishwanathan 《International Journal of Circuit Theory and Applications》2019,47(12):2019-2031
New power control is introduced in the full-bridge dc-dc converter to drive an LED lamp in this paper. LEDs are semiconductor devices that behave like a constant voltage load with low equivalent series resistance (ESR). Hence, they require precise control for current regulation. In the proposed driver, the LED lamp is driven by two voltage sources connected in series through a series resonant circuit. It processes the majority of lamp power through the full-bridge diode rectifier and supplies small power through a center-tapped rectifier. The LED lamp current is controlled at the selected operating current by using center-tapped rectifier output voltage. In addition, pulse-width modulation (PWM) dimming is implemented. The proposed topology features zero-voltage switching (ZVS), regulation of lamp current, dimming operation, and high efficiency. The working principle, performance, and prototype validation are given for the proposed LED driver. 相似文献
7.
LED灯具有节能环保、寿命长、光电效率高等优点。近年来,LED技术飞速进步,白光LED的发光效率不断提升,LED在室内照明、道路照明及广告牌显示等方面得到了广泛应用。但在光电转换效率指标上,LED灯相比荧光灯仍较低。利用LED专用驱动芯片NCP5009,设计了一款LED恒流驱动电源,其光电转换效率高,并可控制电流稳定输出,提高LED管的发光寿命。 相似文献
8.
Chun‐An Cheng Tsung‐Yuan Chung 《International Journal of Circuit Theory and Applications》2016,44(11):1942-1958
This paper proposes a single‐stage light‐emitting diode (LED) driver that offers power‐factor correction and digital pulse–width modulation (PWM) dimming capability for streetlight applications. The presented LED streetlight driver integrates an alternating current–direct current (AC–DC) converter with coupled inductors and a half‐bridge‐type LLC DC–DC resonant converter into a single‐stage circuit topology. The sub‐circuit of the AC–DC converter with coupled inductors is designed to be operated in discontinuous‐conduction mode for achieving input‐current shaping. Zero‐voltage switching of two active power switches and zero‐current switching of two output‐rectifier diodes in the presented LED driver decrease the switching losses; thus, the circuit efficiency is increased. A prototype driver for powering a 144‐W‐rated LED streetlight module with input utility‐line voltages ranging from 100 to 120 V is implemented and tested. The proposed streetlight driver features cost‐effectiveness, high circuit efficiency, high power factor, low levels of input‐current harmonics, and a digital PWM dimming capability ranging from 20% to 100% output rated LED power, which is fulfilled by a micro‐controller. Satisfying experimental results, including dimming tests, verify the feasibility of the proposed LED streetlight driver. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
9.
Mitsuhiro Kadota Hiroyuki Shoji Atsushi Hatakeyama Keiji Wada 《Electrical Engineering in Japan》2019,209(3-4):26-34
This article proposes an LED driver that consists of a ceramic‐capacitor‐input rectifier and a buck‐boost converter. The LED driver has an advantage of long life because it does not contain any electrolytic capacitors. However, the issue with electrolytic capacitor‐less LED driver is that the ripple of the smoothed voltage becomes large due to insufficient capacitance of the smoothing capacitor. The proposed method, which uses the discontinuous current mode of a buck‐boost converter, reduces the output current ripple under such conditions. Experimental results using a 5.7 W LED driver prototype demonstrate that the proposed method reduces the output current ripple and that the percent flicker becomes 4.4%, which is smaller than the recommended upper limit of 8%. 相似文献
10.
Taizhi Zhang Qinsong Qian Shen Xu Shengli Lu Weifeng Sun 《International Journal of Circuit Theory and Applications》2015,43(12):2025-2038
Here, we propose a single‐stage alternating current/direct current electrolytic capacitor‐less light‐emitting diode (LED) driver, which applies interleaving flyback topology to reduce the peak‐to‐average ratio of LED driving current. With this approach, the peak current through LEDs is reduced, so the lifetime requirement of LEDs can be satisfied for an electrolytic capacitor‐less LED driver. A new transformer with two interleaving auxiliary windings is applied to this driver. Based on this approach, compared with other electrolytic capacitor‐less LED drivers, an important advantage of this driver is that it can be easily created, without additional control circuits. We will explain the operation principle and control strategy of the proposed driver in detail and will use experimental results taken from a 24‐V 350‐mA prototype to demonstrate its performance. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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12.
针对LED灯输出电流恒定的工作特性,提出了DC/DC变换器电感电流工作在不断续模式(DCM)下的双输出反激变换器驱动LED的控制方法。主要分析了两路LED灯负载的工作过程,用一个磁性元件实现LED灯两路控制器恒流输出。通过小信号模型分析了系统的稳态、动态和高频干扰抑制能力,最后通过实验验证了所提出的拓扑电路结构和控制方法的可行性。 相似文献
13.
《International Journal of Circuit Theory and Applications》2017,45(11):1801-1813
Bidirectional DC–DC converter with phase‐shift control is commonly used for hybrid electric vehicle and fuel‐cell vehicle applications. This converter is characterized by simple circuit topology and soft‐switching implementation without additional devices. Despite these advantages, the efficiency is poor at light load condition because of high switching and conduction losses caused by high RMS inductor current. To achieve zero‐voltage switching (ZVS) for all power MOSFETs, a constant offset inductor current is maintained to conduct the antiparallel body diodes before MOSFETs turn on. A control strategy of combining duty ratio and phase‐shift modulation is proposed to reach the constant offset current. By reaching the constant offset current, the RMS inductor current can be reduced significantly, and ZVS can be achieved in all load variation ranges, resulting in high efficiency. A 2.5‐kW prototype is implemented to verify the control scheme, and a minimum efficiency of 97.3% is achieved at light load condition. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
14.
Kasi Ramakrishnareddy Ch Shunmugam Porpandiselvi Neti Vishwanathan 《International Journal of Circuit Theory and Applications》2019,47(7):1173-1187
A three-leg resonant converter is proposed to drive two light emitting diode (LED) lamps of different power ratings. This may be required when both main and local lighting are essential. The proposed converter is operated simultaneously at two different frequencies. Two series resonant circuits are used to allow two different frequency currents. Each lamp is powered through a series resonant circuit and is controlled independently. LED lamp currents are regulated at the desired operating current by using phase-modulation control and asymmetrical duty ratio control. In addition, pulse-width modulation (PWM) dimming control is implemented for two LED lamps independently. The proposed topology has advantages of zero-voltage switching (ZVS), regulation of lamp currents, independent illumination control, and high efficiency. A 126-W prototype has been developed experimentally to confirm its working principle, performance, and validity. 相似文献
15.
Huang‐Jen Chiu Yu‐Kang Lo Yu‐Liang Lin Gwan‐Chi Jane 《International Journal of Circuit Theory and Applications》2015,43(3):307-317
This paper presents a novel cost‐effective pulse‐width‐modulation (PWM) dimming method for light‐emitting diode (LED) lighting applications. High efficiency, high power factor, circuit simplicity, and low cost can be achieved by a Flyback power factor correction converter with the studied adaptive PWM dimming method. The operation principles and design considerations of the proposed LED dimming method are analyzed and discussed. A 45 W laboratory prototype has been built and tested to verify the feasibility of the proposed scheme. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
16.
A single‐stage integrated bridgeless AC/DC converter for electrolytic capacitor‐less LED lighting applications
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Hongbo Ma Cong Zheng Wensong Yu Jih‐Sheng Lai 《International Journal of Circuit Theory and Applications》2015,43(6):742-755
In this paper, a single‐stage integrated bridgeless AC/DC converter is proposed. As compared to its counterpart that is composed of totem‐pole boost power factor correction (PFC) cascade fly‐back DC/DC converter, the studied circuit has less components number while overcoming the limits of the totem‐pole type. Thus, it is suitable to the low‐power LED lighting applications. Furthermore, when both PFC inductors Lb and magmatic inductance Lm of the transformer TR1 operate at discontinuous current mode, the bus voltage vCB can be used to decouple the ac input and constant dc output power. Thus, the approach of increasing bus voltage ripple is employed to eliminate electrolytic capacitors and obtain long operation lifetime. Additionally, it is able to be compatible with our studied twin‐bus configuration for increasing the overall efficiency. A 50‐W hardware prototype has been designed, fabricated, and tested in the laboratory to verify the proposed converter validity. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
17.
Analysis and implementation of a high‐efficiency zero‐voltage‐zero‐current‐switching DC–DC converter
Hyun‐Lark Do 《International Journal of Circuit Theory and Applications》2013,41(9):889-903
A high‐efficiency zero‐voltage‐zero‐current‐switching DC–DC converter with ripple‐free input current is presented. In the presented converter, the ripple‐free boost cell provides ripple‐free input current and zero‐voltage switching of power switches. The resonant flyback cell provides zero‐voltage switching of power switches and zero‐current switching of the output diode. Also, it has a simple output stage. The proposed converter achieves high efficiency because of the reduction of the switching losses of the power switches and the output diode. Detailed analysis and design of the proposed converter are carried out. A prototype of the proposed converter is developed and its experimental results are presented for validation. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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19.
Automatic current‐sharing extendable two‐channel LED driver with non‐pulsating input current and zero dc flux
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K.I. Hwu W.Z. Jiang W.H. Chen 《International Journal of Circuit Theory and Applications》2018,46(8):1462-1484
A 2‐channel LED driver is presented herein, which possesses non‐pulsating input current and automatic current sharing. There are 4 features in the proposed LED driver. First, due to an input inductor, the input current is non‐pulsating, which makes the life of the renewable energy module or input capacitor longer. Second, each coupled inductor winding has a capacitor connected in series. Therefore, the dc magnetizing bias current is zero, and this can improve the iron core utilization, making the core loss and size reduced. Third, the number of LED channels can be extended by increasing windings. Fourth, the LED currents can be almost identical even if there are different LED numbers in LED strings. Eventually, the proposed LED driver is verified by simulation and experiment. 相似文献
20.
Yu‐Liang Lin Chung‐Ming Leng Jian‐Min Wang 《International Journal of Circuit Theory and Applications》2016,44(3):683-692
This paper aims to investigate the low dimming switch stress of a light‐emitting diode (LED) driver. Most dimmable LED drivers contain a series dimming switch with a LED string to implement a pulse‐width modulation‐dimming function. However, this setup causes the dimming switch to suffer from high voltage stress in the dimming interval. To reduce the voltage stress of a dimming switch, a low switch stress scheme is presented. The dimming circuit is parallel with the LED string. Using proper arrangement and design of the parameters, the dimming circuit changes the feedback status, which results in the output driving voltage varying between a constant current and a fixed voltage operation. These two operating conditions also make the LED string turn on/off alternately and consequently and perform the dimming function. The dimming switch acts by altering the feedback path instead of cutting off the main power flow; hence, it does not need a power level switch. Details of the operating principles and design considerations are discussed in this study. A prototype boost converter was developed to verify the feasibility of the proposed low dimming switch stress LED driver. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献