Application of an Active DC Link to Commercial LED Driver

This paper explores practical implementation of an active decoupling device integrated into a commercial 120-watt LED driver. The device, employing a series-stacked buffer (SSB)-active DC link, replaces the traditional DC-bus electrolytic capacitor. Utilizing an auxiliary total capacitance smaller than a third of the original capacitance, the device effectively emulates the low-frequency characteristics of a significantly larger capacitance. The central obj ective of this study is to showcase the feasibility of incorporating small electrolytic auxiliary capacitors instead of ceramic class two capacitors and to design a high-power-density, compact electronic board capable of effectively replacing a large electrolytic capacitor. It is essential to note that the objective was not to optimize the physical size or cost of the proposed device but to emphasize its ability to operate identically or even improve the performance of a commercial product. Constraints on applicable auxiliary capacitors, including their rated voltage and maximum ripple current, are also considered. The Total Harmonic Distortion (THD) of the input mains current and DC-bus voltage ripple was compared between the original and modified LED drivers.