Implementation of a Dimmable LED Driver with Extendable Parallel Structure and Capacitive Current Sharing

A dimmable LED driver along with an extendable series structure and interleaved capacitive current sharing is presented herein, the LED connection of which is changed from the traditional series structure to the proposed parallel structure. The number of LED strings can be extended. As the number of LED strings is increased, the output voltage of this LED driver and the voltage stress on the main switch are ideally not influenced. Moreover, only one current sensor is needed to achieve current control and dimming. In this paper, the basic operating principle of the proposed LED driver is described and analyzed. Finally, the effectiveness of this LED driver is demonstrated by experiment based on the field-programmable gate array (FPGA).

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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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Implementation of Coupled Inductor Based 7-level Inverter with Reduced Switches

International Journal of Power Electronics and Drive Systems (IJPEDS) ◽

10.11591/ijpeds.v8.i3.pp1294-1302 ◽

2017 ◽

Vol 8 (3) ◽

pp. 1294 ◽

Cited By ~ 1

Author(s):

R. Palanisamy ◽

K. Vijayakumar ◽

Aishwarya Bagchi ◽

Vachika Gupta ◽

Swapnil Sinha

Keyword(s):

Output Voltage ◽

Control Algorithm ◽

Harmonic Distortion ◽

Current Control ◽

Output Current ◽

Hysteresis Current Control ◽

Common Mode Voltage ◽

Voltage Stress ◽

Dsp Controller ◽

Switching Devices

<p>This paper proposes implementation of coupled inductor based 7 level inverter with reduced number switches. The inverter which generates the sinusoidal output voltage by the use of coupled inductor with reduced total harmonic distortion. The voltage stress on each switching devices, capacitor balancing and common mode voltage can be minimized. The proposed system which gives better controlled output current and improved output voltage with diminished THD value. The switching devices of the system are controlled by using hysteresis current control algorithm by comparing the carrier signals with constant pulses with enclosed hysteresis band value. The simulation and experimental results of the proposed system outputs are verified using matlab/Simulink and TMS320F3825 dsp controller respectively.</p>

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Rogowski Coil for Current Measurement in a Cryogenic Environment

Measurement Science Review ◽

10.1515/msr-2015-0012 ◽

2015 ◽

Vol 15 (2) ◽

pp. 77-84 ◽

Cited By ~ 1

Author(s):

Tao Ma ◽

Shaotao Dai ◽

Jingye Zhang ◽

Lianqi Zhao

Keyword(s):

Output Voltage ◽

Rogowski Coil ◽

Measurement Precision ◽

Current Measurement ◽

Current Sensor ◽

Coil Current ◽

Large Bandwidth ◽

Current Sharing ◽

Primary Current ◽

Better Than

Abstract A Rogowski coil based sensor for current measurement in a cryogenic environment and results of its application for paralleled high temperature superconducting (HTS) coil current sharing are presented. The current sensor consists of a Rogowski coil and an integrator, where the coil output voltage is proportional to the derivative of primary current and the integrator transfers the differentiation to normal state. The Rogowski coil has promising applicability at cryogenic circumstance because its body is made of low temperature materials. The integrator ensures a large bandwidth with feasible magnitude, which is vital for dynamic current measurement during the quench of the HTS coil. The proposed current sensor is used for current sharing measurement of two paralleled Bi2223 HTS coils, and the experimental results show that the measurement precision is better than 0.5%.

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Nonisolated Two-Phase Interleaved LED Driver With Capacitive Current Sharing

IEEE Transactions on Power Electronics ◽

10.1109/tpel.2017.2695006 ◽

2018 ◽

Vol 33 (3) ◽

pp. 2295-2306 ◽

Cited By ~ 10

Author(s):

K. I. Hwu ◽

W. Z. Jiang

Keyword(s):

Two Phase ◽

Led Driver ◽

Capacitive Current ◽

Current Sharing

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Comparison of Dc-Dc SEPIC, CUK and Flyback Converters Based LED Drivers

Light & Engineering ◽

10.33383/2018-70 ◽

2020 ◽

pp. 99-107

Author(s):

Erdal Sehirli

Keyword(s):

Integrated Circuit ◽

Closed Loop ◽

Input Voltage ◽

Open Loop ◽

Current Sensor ◽

Switching Frequency ◽

Led Driver ◽

Advantages And Disadvantages ◽

Led Drivers ◽

Conduction Mode

This paper presents the comparison of LED driver topologies that include SEPIC, CUK and FLYBACK DC-DC converters. Both topologies are designed for 8W power and operated in discontinuous conduction mode (DCM) with 88 kHz switching frequency. Furthermore, inductors of SEPIC and CUK converters are wounded as coupled. Applications are realized by using SG3524 integrated circuit for open loop and PIC16F877 microcontroller for closed loop. Besides, ACS712 current sensor used to limit maximum LED current for closed loop applications. Finally, SEPIC, CUK and FLYBACK DC-DC LED drivers are compared with respect to LED current, LED voltage, input voltage and current. Also, advantages and disadvantages of all topologies are concluded.

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Development of an Induction-Free Current Sensor for Application in Spot-Welding Current Control

IEEJ Transactions on Industry Applications ◽

10.1541/ieejias.132.58 ◽

2012 ◽

Vol 132 (1) ◽

pp. 58-66

Author(s):

Yoshiaki Takasaki ◽

Tatsunori Munesada ◽

Toshikatsu Sonoda

Keyword(s):

Spot Welding ◽

Welding Current ◽

Current Control ◽

Current Sensor ◽

Free Current

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Novel High-Efficiency High Step-Up DC–DC Converter with Soft Switching and Low Component Voltage Stress for Photovoltaic System

Processes ◽

10.3390/pr9071112 ◽

2021 ◽

Vol 9 (7) ◽

pp. 1112

Author(s):

Yu-En Wu ◽

Jyun-Wei Wang

Keyword(s):

High Voltage ◽

Output Voltage ◽

High Efficiency ◽

Low Voltage ◽

Leakage Inductance ◽

Power Switch ◽

Half Wave Voltage ◽

Half Wave ◽

Voltage Stress ◽

Voltage Doubler

This study developed a novel, high-efficiency, high step-up DC–DC converter for photovoltaic (PV) systems. The converter can step-up the low output voltage of PV modules to the voltage level of the inverter and is used to feed into the grid. The converter can achieve a high step-up voltage through its architecture consisting of a three-winding coupled inductor common iron core on the low-voltage side and a half-wave voltage doubler circuit on the high-voltage side. The leakage inductance energy generated by the coupling inductor during the conversion process can be recovered by the capacitor on the low-voltage side to reduce the voltage surge on the power switch, which gives the power switch of the circuit a soft-switching effect. In addition, the half-wave voltage doubler circuit on the high-voltage side can recover the leakage inductance energy of the tertiary side and increase the output voltage. The advantages of the circuit are low loss, high efficiency, high conversion ratio, and low component voltage stress. Finally, a 500-W high step-up converter was experimentally tested to verify the feasibility and practicability of the proposed architecture. The results revealed that the highest efficiency of the circuit is 98%.

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