scholarly journals A Single-Stage High Power Factor Power Supply for Providing an LED Street-Light Lamp Featuring Soft-Switching and Bluetooth Wireless Dimming Capability

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 477
Author(s):  
Chun-An Cheng ◽  
Hung-Liang Cheng ◽  
Chien-Hsuan Chang ◽  
En-Chih Chang ◽  
Wei-Shiang Hung ◽  
...  
Keyword(s):  
Energy Saving ◽  
Power Factor ◽  
High Power ◽  
Power Supply ◽  
Buck Converter ◽  
Single Stage ◽  
Two Stage ◽  
High Power Factor ◽  
Power Switches ◽  
Dimming Control

Light-emitting diode (LED) has the characteristics of environmental protection and energy saving, having become the lighting source of a new generation of street-light lamps. The traditional two-stage power supply for providing an LED street-light lamp is composed of an AC-DC converter with a power-factor-correction (PFC) function at the front stage and a DC-DC converter at the rear stage. The two-stage power supply for an LED street-light lamp has a large number of electronic components and costs, and the circuit efficiency is not high. Therefore, this paper presents a novel single-stage high power factor AC-DC power supply for providing an LED street-light lamp featuring soft-switching and Bluetooth wireless dimming capability through using smart tablets or smartphones to remote control the output power of the LED street-light lamp for achieving energy-saving benefits. The proposed AC-DC LED power supply integrates an interleaved buck converter circuit with coupled inductors and a half-bridge LLC resonant converter circuit into a single-stage power conversion circuit. Moreover, the coupled inductor of the interleaved buck converter circuit is designed to operate in the discontinuous conduction mode, which can naturally achieve PFC. In addition, the two power switches in the novel LED power supply have zero-voltage switching (ZVS) characteristics, which can reduce the switching losses of the power switches. The two output diodes have the characteristics of zero-current switching (ZCS), which can reduce the conduction losses of the power diodes. This paper developed a single-stage prototype circuit for providing an 144 W (36 V/4 A)-rated LED street-light lamp. According to the experimental results of the prototype circuit with an AC input voltage of 110 volts, the presented single-stage LED power supply offers high power factor (PF > 0.99), low input-current total harmonic distortion factor (THD < 3%), and high efficiency (>89%). In addition, this paper used the built-in Bluetooth wireless communication function of a smart tablet or smart phone to fulfill remote dimming control. By changing the duty ratio of the control signal, we could realize remote dimming control of 20% to 100% of the output LED street-light lamp power.

Two-Stage Uninterruptible Power Supply With High Power Factor

2008 ◽  
Vol 55 (8) ◽  
pp. 2954-2962 ◽  
Author(s):  
N. Vazquez ◽  
J. Villegas-Saucillo ◽  
C. Hernandez ◽  
E. Rodriguez ◽  
J. Arau
Keyword(s):  
Power Factor ◽  
High Power ◽  
Power Supply ◽  
Two Stage ◽  
Uninterruptible Power Supply ◽  
High Power Factor ◽  
Uninterruptible Power

scholarly journals A Single-Stage High-Power Factor Converter with Synchronized Self-Excited Technique for LED Lighting

2018 ◽  
Vol 8 (8) ◽  
pp. 1408 ◽  
Author(s):  
Yong-Nong Chang ◽  
Shun-Yu Chan ◽  
Hung-Liang Cheng
Keyword(s):  
Resonant Frequency ◽  
Power Factor ◽  
High Power ◽  
Single Stage ◽  
Switching Frequency ◽  
Resonant Converter ◽  
Switching Loss ◽  
Led Driver ◽  
High Power Factor ◽  
Power Switches

This paper proposes a single-stage, high power-factor light-emitting diode (LED) driver with a self-excited control scheme for the power switches. The self-excited mechanism is accomplished by fetching the driving voltages from a center-tapped transformer. The frequency of the driving voltages is exactly the same as the resonant frequency of the resonant converter, thus synchronizing the resonant frequency with the switching frequency and achieving zero-voltage switching (ZVS) and zero-current switching (ZCS) of power switches. The circuit topology is mainly composed of a half-bridge LC resonant converter, along with a boost-type power-factor corrector (PFC) to fulfill the single-stage structure, meaning that the presented LED driver possesses high power-factor features and low switching loss. Finally, a 40 W prototype circuit is implemented and tested, and the experimental results exhibit a satisfactory performance.

scholarly journals A Novel Single-Switch Single-Stage LED Driver with Power Factor Correction and Current Balancing Capability

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1340
Author(s):  
Yih-Her Yan ◽  
Hung-Liang Cheng ◽  
Chun-An Cheng ◽  
Yong-Nong Chang ◽  
Zong-Xun Wu
Keyword(s):  
Power Factor ◽  
High Power ◽  
Pulse Width Modulation ◽  
Power Factor Correction ◽  
Harmonic Distortion ◽  
Boost Converter ◽  
Single Stage ◽  
Led Driver ◽  
Flyback Converter ◽  
High Power Factor

A novel single-switch single-stage high power factor LED driver is proposed by integrating a flyback converter, a buck–boost converter and a current balance circuit. Only an active switch and a corresponding control circuit are used. The LED power can be adjusted by the control scheme of pulse–width modulation (PWM). The flyback converter performs the function of power factor correction (PFC), which is operated at discontinuous-current mode (DCM) to achieve unity power factor and low total current harmonic distortion (THDi). The buck–boost converter regulates the dc-link voltage to obtain smooth dc voltage for the LED. The current–balance circuit applies the principle of ampere-second balance of capacitors to obtain equal current in each LED string. The steady-state analyses for different operation modes is provided, and the mathematical equations for designing component parameters are conducted. Finally, a 90-W prototype circuit with three LED strings was built and tested. Experimental results show that the current in each LED string is indeed consistent. High power factor and low THDi can be achieved. LED power is regulated from 100% to 25% rated power. Satisfactory performance has proved the feasibility of this circuit.

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