scholarly journals High Voltage, Low Current High-Power Multichannel LEDs LLC Driver by Stacking Single-Ended Rectifiers with Balancing Capacitors

Electronics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 529
Author(s):  
Kang Hyun Yi
Keyword(s):  
High Voltage ◽  
High Power ◽  
Low Voltage ◽  
Driving Voltage ◽  
Led Driver ◽  
Leakage Inductance ◽  
Voltage Stress ◽  
Driver Circuit ◽  
In Series ◽  
The Difference

In this paper, a new LLC converter for series-connected, high-voltage LEDs is proposed. The proposed LLC converter consists of two stacked, single-ended rectifiers and one balancing capacitor, to compensate for the current deviation of two individual LED strings. The proposed LLC LED driver can use a diode with low voltage stress, even if the secondary LED is connected in series to have a high driving voltage. In addition, even if several series-connected LEDs are changed into two-stacked structures, the balancing capacitor can compensate for the current deviation of the two separated LEDs, as well as the difference in leakage inductance of the two stacked single-ended rectifiers. The balancing capacitor can be made equal to the voltage tolerance of the stacked, single-ended rectifier diodes. The proposed circuit can be easily extended to a series channel LED driver circuit, without increasing the voltage stress. To verify the characteristics and operation of the proposed LLC LED driver, a 260W high-power LED driver is implemented.

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

Processes ◽  
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%.

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

Energies ◽  
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.

A High-Voltage ZVZCS DC--DC Converter With Low Voltage Stress

2008 ◽  
Vol 23 (6) ◽  
pp. 2630-2647 ◽  
Author(s):  
Ting-Ting Song ◽  
Huai Wang ◽  
H.S.-H. Chung ◽  
S. Tapuhi ◽  
A. Ioinovici
Keyword(s):  
High Voltage ◽  
Low Voltage ◽  
Voltage Stress

scholarly journals High Step-up Coupled Inductor Inverters Based on qSBIs

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 3032 ◽  
Author(s):  
Hongchen Liu ◽  
Xi Su ◽  
Junxiong Wang
Keyword(s):  
Steady State ◽  
High Voltage ◽  
Low Voltage ◽  
Duty Ratio ◽  
Voltage Gain ◽  
Passive Components ◽  
Steady State Analysis ◽  
High Voltage Gain ◽  
Voltage Stress ◽  
Working Principle

In this paper, two types of high step-up coupled inductor inverters based on qSBIs (quasi- switched boost inverters) are proposed. By applying the coupled inductor to the qSBIs, the voltage gain of the proposed inverter is regulated by turn ratio and duty ratio. Thus, a high voltage gain can be achieved without the circuits operating at the extreme duty cycle by choosing a suitable turn ratio of the coupled inductor. In addition, the proposed circuits have the characteristics of continuous input current and low voltage stress across the passive components. A boost unit can be added to the proposed inverters for further improvement of the voltage gain. In this paper, the working principle, steady state analysis, and the comparisons of the proposed inverter with other impedance-source inverters are described. A 200 W prototype was created and the experimental results confirm the correctness of the analysis in this paper.

A scalable strategy toward compliant tandem yarn-shaped supercapacitors with high voltage output

2021 ◽  
Author(s):  
Juan Zhang ◽  
Qingli Xu ◽  
Xiangyu Qian ◽  
Xinhou Wang ◽  
Kun Zhang
Keyword(s):  
High Voltage ◽  
Aqueous Electrolyte ◽  
Low Voltage ◽  
Voltage Output ◽  
In Series

Yarn-shaped supercapacitors (YSSCs) based on aqueous electrolyte exhibit relatively low voltage output due to the low decomposition voltage of water (~1.23 V). Applying organic-based electrolyte or connecting YSSCs in series...

A Single-Stage LED Driver Based on Flyback and Modified Class-E Resonant Converters With Low-Voltage Stress

2019 ◽  
Vol 66 (11) ◽  
pp. 8463-8473 ◽  
Author(s):  
Yijie Wang ◽  
Fang Li ◽  
Yuping Qiu ◽  
Shanshan Gao ◽  
Yueshi Guan ◽  
...  
Keyword(s):  
Low Voltage ◽  
Single Stage ◽  
Resonant Converters ◽  
Led Driver ◽  
Voltage Stress ◽  
Class E

scholarly journals Experimental Investigation of the Prestrike Characteristics of a Double-Break Vacuum Circuit Breaker under DC Voltages

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3217
Author(s):  
Yun Geng ◽  
Xiaofei Yao ◽  
Jinlong Dong ◽  
Xue Liu ◽  
Yingsan Geng ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Direct Current ◽  
Experimental Work ◽  
Low Voltage ◽  
Circuit Breaker ◽  
Circuit Breakers ◽  
Vacuum Circuit Breaker ◽  
In Series ◽  
The Difference ◽  
Single Break

The prestrike phenomenon in vacuum circuit breakers (VCBs) is interesting but complicated. Previous studies mainly focus on the prestrike phenomenon in single-break VCBs. However, experimental work on prestrike characteristics of double-break VCBs cannot be found in literature. This paper aims to experimentally determine the probabilistic characteristics of prestrike gaps in a double-break VCB consisting of two commercial vacuum interrupters (VIs) in series under direct current (DC) voltages. As a benchmark, single-break prestrike gaps were measured by short-circuiting one of the VIs in a double break. The experimental results show that the 50% prestrike gap d50 of each VI in a double break, which is calculated with the complementary Weibull distribution, was significantly reduced by 25% to 72.7% compared with that in a single break. Due to the voltage-sharing effect in the double-break VCB, scatters in prestrike gaps of each VI in a double break was smaller than that in a single break. However, without the sharing-voltage effect, d50 of the low-voltage side in the double break was 65% higher than that of the same VI in the single break, which could be caused by the asynchronous property of mechanical actuators, the difference of the inherent prestrike characteristics of each VI and the unequal voltage-sharing ratio of VIs.

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