scholarly journals Analysis and Control of Electrolytic Capacitor-Less LED Driver Based on Harmonic Injection Technique

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3030 ◽  
Author(s):  
Mahmoud Nassary ◽  
Mohamed Orabi ◽  
Manuel Arias ◽  
Emad Ahmed ◽  
El-Sayed Hasaneen
Keyword(s):  
Power Factor ◽  
Low Frequency ◽  
Buck Converter ◽  
Electrolytic Capacitor ◽  
Injection Technique ◽  
Led Driver ◽  
Harmonic Injection ◽  
Output Capacitor ◽  
And Control ◽  
Led Drivers

AC-DC LED drivers may have a lifespan shorter than the lifespan of LED chips if electrolytic capacitors are used in their construction. Using film capacitors solves this problem but, as their capacitance is considerably lower, the low-frequency ripple will increase. Solving this problem by limiting the output ripple to safe values is possible by distorting the input current using harmonic injection technique, as long as these harmonics still complies with Power Factor Regulations (Energy Star). This harmonic injection alleviates the requirements imposed to the output capacitor in order to limit the low-frequency ripple in the output. This idea is based on the fact that LEDs can be driven by pulsating current with a limited Peak-To-Average Ratio (PTAR) without affecting their performance. By considering the accurate model of LEDs, instead of the typical equivalent resistance, this paper presents an improved and more reliable calculation of the intended harmonic injection. Wherein, its orders and values can be determined for each input/output voltage to obtain the specified PTAR and Power Factor (PF). Also, this harmonic injection can be simply implemented using a single feedback loop, its control circuit has features of wide bandwidth, simple, single-loop and lower cost. A 21W AC-DC buck converter is built to validate the proposed circuit and the derived mathematical model and it complies with IEC61000 3-2 class D standard.

scholarly journals DC-DC converter Topologies for LED Driver Circuit: A Review

2020 ◽  
Vol 14 ◽  
Keyword(s):  
Power Factor ◽  
Power Conversion ◽  
Buck Converter ◽  
Led Driver ◽  
Dc Power ◽  
High Power Factor ◽  
Driver Circuit ◽  
Converter Topologies ◽  
Long Lifetime ◽  
Led Drivers

It has been noticed that in commerciallighting, in terms of efficiency light-lamps based on lightemitting diodes(LEDs) are far better as compared to thosewhere traditional high-pressure sodium (HPS) lampswhich are still in use in major underdeveloped anddeveloping areas worldwide in specifically street lighting.The LED driver is an electrical device which controlspower flow to the single LED or a string of the LEDs orcontrols to the current flowing through the LEDs.Available conventional topologies for LED drivers haveseveral demerits such as flickering issues, high losses,luminance problems, low power factor, more number ofswitches etc. So, the need of the hour is to develop efficient,compact, long lifetime, high power factor and flicker-freeLED drivers. The LED have numerous advantages such ashigh luminous efficiency, life span and it has no mercuryin its composition. Therefore, recently researchers of thisarea has been setting a goal to utilize LED as a goodalternative to save electricity from major parts of thisplanet.In this paper, various topologies of LED drivers arepresented. This paper also portrays simulation of a LEDdriver which is based on the combination of the buckboost converter as power factor correction stage (PFC)and buck converter as dc-dc power conversion (PC) stage.Both the stages are integrated using single switch only so itis basically integrated LED driver circuit.

scholarly journals Optimization of a Series Converter for Low-Frequency Ripple Cancellation of an LED Driver

Electronics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 664 ◽  
Author(s):  
Jorge Garcia ◽  
Sarah Saeed ◽  
Pablo Quintana ◽  
Jesus Cardesin ◽  
Ramy Georgious ◽  
...  
Keyword(s):  
Low Frequency ◽  
Current Control ◽  
Buck Converter ◽  
Constant Current ◽  
Led Driver ◽  
Original Proposal ◽  
Voltage Ripple ◽  
Power And Control ◽  
Optimization Methodology ◽  
And Control

In this paper, the optimization of the power and control stages of a previously proposed topology for an off-line LED electronic driver is presented. The full system avoids the use of electrolytic capacitors at the D C link, therefore increasing the lifespan and reliability of the driver. As a consequence of having a relatively small capacitance, the D C link operates with a large Low-Frequency ( L F ) voltage ripple. This work presents a design optimization for the power and control stages of a current-fed bidirectional buck converter, operating as the LED current control stage. As this block processes only the A C power arising from the L F voltage ripple, it can increase the system efficiency against the typical two-stage solution. In the original proposal, the main drawback was the high inductor losses due to the resulting large inductor currents and large inductance value. The proposed optimization ensures an enhanced design of the inductor while keeping a constant current through the LEDs. A new optimization methodology is proposed and the theoretical results have been validated in a built prototype for a 40 W LED lamp.

High‐power‐factor dimmable LED driver with low‐frequency pulse‐width modulation

2016 ◽  
Vol 9 (10) ◽  
pp. 2139-2146 ◽  
Author(s):  
Hung‐Liang Cheng ◽  
Yong‐Nong Chang ◽  
Chun‐An Cheng ◽  
Chien‐Hsuan Chang ◽  
Yu‐Hung Lin
Keyword(s):  
Power Factor ◽  
High Power ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Low Frequency ◽  
Led Driver ◽  
High Power Factor ◽  
Frequency Pulse

Design of a high-power factor offline led driver employing a Ćuk-based low frequency pre-regulator

2017 ◽  
Author(s):  
Fernando J. Nogueira ◽  
Lucas H. G. Resende ◽  
Edmar S. Silva ◽  
Felipe B. Marinho ◽  
Cristiano G. Casagrande ◽  
...  
Keyword(s):  
Power Factor ◽  
High Power ◽  
Low Frequency ◽  
Led Driver ◽  
High Power Factor

scholarly journals ESR Estimation Schemes of Output Capacitor for Buck Converter from Capacitor Perspective

Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1596
Author(s):  
Lei Ren ◽  
Lei Zhang ◽  
Chunying Gong
Keyword(s):  
Buck Converter ◽  
Electrolytic Capacitor ◽  
Equivalent Series Resistance ◽  
Power Electronic Converters ◽  
Aluminum Electrolytic Capacitor ◽  
Advantages And Disadvantages ◽  
Optimal Period ◽  
Current Characteristics ◽  
Output Capacitor ◽  
Conduction Mode

The aluminum electrolytic capacitor (AEC) is one of the most vulnerable parts in power electronic converters and its reliability is crucial to the whole system. With the growth of service time, the equivalent series resistance (ESR) increases and the capacitance (C) decreases due to the loss of electrolytes, which will result in extra power loss and even damage to transistors. To prevent significant damages, the AEC must be replaced at an optimal period and online health monitoring is indispensable. Through the analysis of degradation parameters (ESR and C), ESR is proved to be a better health indicator and therefore is determined as the monitoring parameter for AEC. From the capacitor perspective, ESR estimation schemes of output capacitors for a Buck converter are studied. Based on the voltage–current characteristics, two ESR calculation models are proposed, which are applicable for both continuous conduction mode (CCM) and discontinuous conduction mode (DCM). From the point of implementation view, the advantages and disadvantages of the two estimation schemes are pointed out, respectively. A Buck prototype is built and tested, and simulation and experimental results are provided to validate the proposed ESR estimation schemes.

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