LED DRIVES
| S.NO | TITLES | ABSTARCTS | Year |
| PED-1 | A High Power Factor, Electrolytic Capacitor-Less AC-Input LED Driver Topology With High Frequency Pulsating Output Current | Light emitting diode (LED) lamps with ac-input (50or 60 Hz) usually require an electrolytic capacitor as the dc-linkcapacitor in the driver circuit to: 1) balance the energy between the input and output power, and 2) to minimize the low-frequency component of the output ripple across the LEDs. The lifetime of this capacitor, however, is much shorter than that of a LED. To maximize the potential lifetime of the LED lighting system, a new pulsating current driving LED driver that does not require any electrolytic capacitors or complicated control circuits to minimizethe low-frequency (i.e., 100 or 120 Hz) output ripple is proposed in this paper. The proposed circuit is simple and a single-switch topology is designed to simplify the controller design. The proposed circuit is able to reduce the energy storage capacitance to a few microfarads range, so that film capacitor can be used to replace the unreliable electrolytic capacitor. The circuit operating principles and its theoretical analysis are provided in this paper. Simulation and experimental results are given on a 9-W LED lamp to highlight the merits of the proposed circuit. | 2015 |
| PED-2 | Design and Implementation of a Single-Stage Driver for Supplying an LED Street-Lighting Module WithPower Factor Corrections | This paper proposes a novel single-stage light emitting diode (LED) driver for street-lighting applications with power factor corrections (PFC). The presented driver integrates a modified bridgeless PFC ac–dc converter with a half-bridge-type LLC dc–dc resonant converter into a single-stage conversion circuit topology. The proposed ac–dc resonant driver provides input current shaping, and it offers attributes of lowered switching losses to the soft-switching functions obtained on two power switches and two output-rectifier diodes. The proposed driver features cost effectiveness, high circuit efficiency (>92%), high power factor (>0.99) and low input current total harmonics distortion (<8%). A prototype driver is developed for supplying a 144-W-rated LED street-lighting module with utility-line input voltages ranging from 100 to 120 V, and experimental results demonstrate the functionalitiesof the proposed LED driver. | 2015 |
| PED-3 | Power Flow Analysis and Critical Design Issues of Retrofit Light-Emitting Diode (LED) Light Bulb | For retrofit applications, some high-brightness light-emitting diode (LED) products have the same form factorrestrictions as existing incandescent light bulbs. Such form factor constraints may restrict the design and optimal erformance of the LED technology. In this paper, some critical design issues for commercial LED bulbs designed for replacing E27 incandescent lamps are quantitatively analyzed. The analysis involves power audits on such densely packed LED systems so that the amounts of power consumption in: 1) the LED wafer; 2) the phosphor coating; and 3) the lamp translucent cover are quantified. The outcomes of such audits enable R&D engineers to identify the critical areas that need further improvements in a compact LED bulb design. The strong dependence of the luminous output of the compact LED bulb on ambient temperature is also highlighted. | 2015 |
| PED-4 | Proportional-Integral (PI) Compensator Design ofDuty-Cycle-Controlled Buck LED Driver | A discrete time-domain modeling and design for the duty-cycle-controlled buck light-emitting diode (LED) driver ispresented in this paper. The discrete time-domain equation representing the buck LED driver is derived and linearized about the equilibrium state. Also the switching control law, the proportional integral (PI) compensator is used here as an example of the error amplifier, is liberalized about the equilibrium state. The liberalized buck LED driver and the control law are then combined to arrive at a liberalized duty-cycle-controlled buck LED driver. The root locus method is employed to analyze the dynamic performance of the closed-loop system. Based on the modeling result, a practical design equation for the PI compensator is derived. Experimental results are presented to verify the validity of the proposed PI compensator design. | 2015 |
| PED-5 | A Current-Sourced LED Driver Compatible With Fluorescent Lamp Ballasts | A light-emitting diode (LED) driver compatible with fluorescent lamp (FL) ballasts is presented for a lamp-only replacement without rewiring the existing lamp fixture. Ballasts have a common function to regulate the lamp current, despite widely different circuit topologies. In this paper, magnetic and electronic ballasts are modeled as non ideal current sources and a current sourced boost converter, which is derived from the duality, is adopted for the power conversion from ballasts. A rectifier circuit with capacitor filaments is proposed to interface the converter with the four-wire output of the ballast. A digital controller emulates the high-voltage discharge of the FL and operates adaptively with various ballasts. A prototype 20- W LED driver for retrofitting T8 36-W FL is evaluated with both magnetic and electronic ballasts. In addition to wide compatibility, accurate regulation of the LED current within 0.6% error and high driver efficiency over 89.7% are obtained. | 2015 |
| PED-6 | Filter Capacitor Minimization in a Flyback LED Driver Considering Input Current Harmonics and Light Flicker Characteristics | In this paper, a comprehensive study is conducted on reducing the size of output filter capacitor in an ac–dc fly back converter for driving high-brightness LED strings. To this end, a relationship between the input current harmonics, LED light flicker, and the magnitude of filter capacitor is obtained. It is shown that the size of the filter capacitor is mostly affected by the amplitude of the third and fifth harmonics of input current and the outputlight flicker. Considering the EN61000-3-2 standard for input current harmonics content and ENERGY STAR standard for flicker requirement, a procedure for obtaining the minimum value of filter capacitance is presented. Experimental studies are performed on an ac–dc fly back LED driver using the proposed method and tested on Cree X Lamp XP-G and CR22-32L LED strings. | 2015 |
| PED-7 | A Novel Primary-Side Controlled Universal-Input AC–DC LED Driver Based on a Source-DrivingControl Scheme | A novel primary-side controlled universal-input ac–dc LED driver based on the source-driving control scheme is proposed in this paper, which employs low-voltage control MOSFETM2 to drive high-voltage power MOSFETM1 without an auxiliary winding commonly used in the conventional primary-side controlled scheme. The proposed control IC adopts minimum voltage detection circuit to monitor the zero crossing information of secondary winding current. The demagnetization time signal is generated by demagnetization time detection circuit. In addition, the ratio betweenthe secondary winding demagnetization time TDemag and switching period TS is maintained constant by adopting the intelligent charging and discharging circuit, finally achieving highprecision constant output current. A control IC for the proposed LED driver has been fabricated in TSMC 0.35 μm 5 V/600 V CMOS/LDMOS process. Experimental results of a 3-W circuit prototype show that the constant current precision is within ±1% in a wide range of universal-input ac voltage from 85 to 264 V, and that above 80% efficiency is obtained when driving three 1-W LEDs. The start-up time is only 46 ms under 90 Vac and 60 Hzinput, and the standby power is tested to be lower than 142 mW under 220 Vac and 50 Hz-input. | 2015 |
ieee 2015 power electronics led drives project titles