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

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 42094-42106
Author(s):  
Lei Yang ◽  
Wenqian Yu ◽  
Jiaxiang Zhang

This article discusses a switched capacitor-based converter to drive high power light emitting diodes (LEDs). The current pulse is provided by a switched capacitor, which is differing from that of conventional constant current dc drivers. The proposed approach differs from the traditional switched-capacitor-based one, because it uses a small inductor to improve the switching behaviour of the converter. The effects of switching devices on the proposed converter are evidenced and evaluated, based on the charge control analysis.Experimental results are presented and discussed to demonstrate the technical feasibility of the proposed MSC converter applied as LED driver through Matlab simulation and hardware result.


2018 ◽  
Vol 46 (8) ◽  
pp. 1485-1502 ◽  
Author(s):  
Juan C. Castellanos ◽  
M. Turhan ◽  
Marcel A.M. Hendrix ◽  
Arthur van Roermund ◽  
Eugenio Cantatore

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3389 ◽  
Author(s):  
Chivon Choeung ◽  
Meng Leang Kry ◽  
Young Il Lee

This paper presents a robust control technique for three-phase chargers under unbalanced grid conditions. The control method consists of inner-loop robust grid-current control and outer-loop proportional integral control for constant current (CC) and constant voltage (CV) control. A dual-current control for the inner-loop positive and negative sequence is employed to eliminate the unbalanced current caused by the grid so that a constant current and voltage can be provided to the batteries. The inner-loop robust controllers utilize state feedback with integral action in the dq-synchronous frame. A linear matrix inequality-based optimization scheme is used to determine stabilizing gains of the controllers to maximize the convergence rate to steady state in the presence of uncertainties. The uncertainties of the system are described as the potential variation range of the inductance and resistance in the L-filter.


Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 112
Author(s):  
Wen-Zhuang Jiang ◽  
Kuo-Ing Hwu ◽  
Jenn-Jong Shieh

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.


Author(s):  
Seong-Mi Park ◽  
Sung Geun Song ◽  
Sang Hun Lee

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