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

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.

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

Energies ◽

10.3390/en11113030 ◽

2018 ◽

Vol 11 (11) ◽

pp. 3030 ◽

Cited By ~ 7

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.

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Variable Frequency Constant Current Control Method for Switched-Capacitor Converter Based Automotive LED Driver

IEEE Access ◽

10.1109/access.2019.2907983 ◽

2019 ◽

Vol 7 ◽

pp. 42094-42106

Author(s):

Lei Yang ◽

Wenqian Yu ◽

Jiaxiang Zhang

Keyword(s):

Control Method ◽

Current Control ◽

Constant Current ◽

Variable Frequency ◽

Switched Capacitor ◽

Led Driver ◽

Switched Capacitor Converter

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Choice of power and control coupling elements for dimmable led driver for smart lighting networks

IECON 2013 - 39th Annual Conference of the IEEE Industrial Electronics Society ◽

10.1109/iecon.2013.6700109 ◽

2013 ◽

Cited By ~ 2

Author(s):

Olegs Tetervenoks

Keyword(s):

Led Driver ◽

Smart Lighting ◽

Power And Control ◽

And Control

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Modelling and Control of Two Stage High PFC LED Driver Circuit using Average Current Control Method Driven by Vienna Rectifier

2020 IEEE 9th Power India International Conference (PIICON) ◽

10.1109/piicon49524.2020.9113062 ◽

2020 ◽

Author(s):

Vinod Kumar Yadav ◽

Arun Kumar Verma ◽

Udaykumar R. Yaragatti

Keyword(s):

Control Method ◽

Current Control ◽

Two Stage ◽

Led Driver ◽

Vienna Rectifier ◽

Driver Circuit ◽

Average Current ◽

Average Current Control ◽

And Control

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ZVS Analysis and Control Strategy for Back-Stage of Single-Phase AC-DC-DC Converter With Low-Frequency DC-Link Voltage Ripple

10.1109/iciea51954.2021.9516166 ◽

2021 ◽

Author(s):

Linzhe Li ◽

Linghui Meng ◽

Shuai Zhang ◽

Tianxiang Wang ◽

Zeliang Shu

Keyword(s):

Control Strategy ◽

Single Phase ◽

Low Frequency ◽

Voltage Ripple ◽

Back Stage ◽

And Control

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LLC LED Driver with Current-Sharing Capacitor Having Low Voltage Stress

Energies ◽

10.3390/en14010112 ◽

2020 ◽

Vol 14 (1) ◽

pp. 112

Author(s):

Wen-Zhuang Jiang ◽

Kuo-Ing Hwu ◽

Jenn-Jong Shieh

Keyword(s):

Low Voltage ◽

Light Emitting Diode ◽

Input Voltage ◽

Current Control ◽

Constant Current ◽

Resistive Load ◽

Led Driver ◽

Current Sharing ◽

Voltage Stress ◽

The Difference

In this paper, an LLC light-emitting diode (LLC LED) driver based on the current-sharing capacitor is presented. In the proposed LED driver, the LLC resonant converter is used to step down the high input voltage, to provide galvanic isolation, to offer a constant current for LEDs. Moreover, the current-sharing capacitor connected to the central-tapped point of the secondary-side winding is used to balance the currents in two LED strings. By doing so, the voltage stress on this capacitor is quite low. Above all, the equivalent forward voltages of the two LED strings are generally influenced by the temperature and the LED current, and this does not affect the current-sharing performance, as will be demonstrated by experiment on the difference in number of LEDs between the two LED strings. In addition, only the current in one LED string is sensed and controlled by negative feedback control, while the current in the other LED string is determined by the current-sharing capacitor. Moreover, this makes the current control so easy. Afterwards, the basic operating principles and analyses are given, particularly for how to derive the effective resistive load from the LED string. Eventually, some experimental results are provided to validate the effectiveness of the proposed LED driver.

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Research on Dual-Carrier Pulse-Train-Controlled Buck Converter

Journal of Control Science and Engineering ◽

10.1155/2019/7514621 ◽

2019 ◽

Vol 2019 ◽

pp. 1-9

Author(s):

Ming Qin ◽

Shiwei Li

Keyword(s):

Pulse Train ◽

Output Voltage ◽

Low Frequency ◽

Buck Converter ◽

Control Technique ◽

Operating Characteristics ◽

Low Frequency Oscillation ◽

Switching Converter ◽

Controlled Switching ◽

Voltage Ripple

In order to solve the low-frequency oscillation of pulse-train- (PT-) controlled switching converter operating in a continuous conduction mode (CCM), a dual-carrier pulse-train (DCPT) control technique is proposed in this paper. With the CCM buck converter as an example, the operational principle, pulse control law, and output voltage ripple of the DCPT-controlled converter are studied. The experimental results are provided to verify the theoretical analysis and simulation results. Compared with the PT-controlled converter, the DCPT-controlled CCM buck converter enjoys much better operating characteristics and smaller output voltage ripple.

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Simple LED driver with Constant Current Control

Journal of international Conference on Electrical Machines and Systems ◽

10.11142/jicems.2014.3.4.422 ◽

2014 ◽

Vol 3 (4) ◽

pp. 422-427

Author(s):

Seong-Mi Park ◽

Sung Geun Song ◽

Sang Hun Lee

Keyword(s):

Current Control ◽

Constant Current ◽

Led Driver

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Design and Implementation of a Dimmable LED Driver with Low-Frequency PWM Control

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.284-287.2538 ◽

2013 ◽

Vol 284-287 ◽

pp. 2538-2542

Author(s):

Hung Liang Cheng ◽

Chun An Cheng ◽

Chao Shun Chen ◽

Kuan Lung Huang

Keyword(s):

High Frequency ◽

High Efficiency ◽

Low Frequency ◽

Buck Converter ◽

Duty Ratio ◽

Buck Converters ◽

Resonant Converter ◽

Switching Loss ◽

Led Driver ◽

Frequency Pulse

This paper proposes a high-efficiency dimmable LED driver for light emitting diodes (LED). The developed LED driver consists of a full-bridge resonant converter and six buck converters. The function of the full-bridge resonant converter is to obtain a smooth dc-link voltage for the buck converters by phase-shift modulation (PSM) while that of the six buck converters is to drive six LED modules, respectively. The gate voltage of the active switch of each buck converter is a combination of high-frequency and low-frequency pulses. The duty ratio of the high-frequency pulse controls the LED voltage and thereby, controls the amplitude of LED current. LEDs are dimmed by low-frequency pulse-width modulation (PWM) to vary the average current flowing through LED. Circuit equations are derived and circuit parameters are designed. High circuit efficiency is ensured by operating the active switches at zero-voltage switching-on to reduce the switching loss. Finally, a prototype circuit was built to verify the accuracy and feasibility of the proposed LED driver.

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