Flicker‑free single‑stage LED drivers based on load current feedback strategy


Vol. 23, No. 11, pp. 1767-1777, Nov. 2023
10.1007/s43236-023-00661-9




 Abstract

The traditional AC/DC light-emitting diode (LED) driver with high power factor causes LED flicker because of the imbalance between the fluctuating instantaneous AC input power and the DC output power. Large electrolytic capacitors are commonly connected in parallel as an energy storage element on the load side to absorb the output ripple and restrain LED flicker. However, the electrolytic capacitor’s short lifespan and high temperature instability reduce the reliability of LED drivers. To realize a new flicker-free LED driver with low cost and high reliability, a series second harmonic current compensation circuit (series SHCC) powered by double vice-side windings is adopted based on single-stage resonant LLC converter in this study, and a new control strategy based on load current feedback is proposed. The proposed load current feedback strategy (LCFS) is analyzed and optimized from the perspective of closed-loop output impedance to minimize the output current ripple and suppress LED flicker. The proposed LCFS is applicable to LED load, and the main-stage PFC based on LLC and the SHCC based on Buck can share the same current sampling circuit, which can evidently simplify the control circuit to achieve a low-cost design. Finally, a 240W experimental LED driver prototype with a wide input and output range is established. The experimental results demonstrate that under rated power, the output current fluctuation depth ( Mod_I(%) ) of the LED driver can be reduced to 3.93%, and the storage capacitance can be decreased by 89.7% under the same fluctuation depth.


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Cite this article

[IEEE Style]

Y. Zhou, Q. Lou, X. He, R. Yuan, "Flicker‑free single‑stage LED drivers based on load current feedback strategy," Journal of Power Electronics, vol. 23, no. 11, pp. 1767-1777, 2023. DOI: 10.1007/s43236-023-00661-9.

[ACM Style]

Yuefei Zhou, Qiongya Lou, Xueru He, and Runzhi Yuan. 2023. Flicker‑free single‑stage LED drivers based on load current feedback strategy. Journal of Power Electronics, 23, 11, (2023), 1767-1777. DOI: 10.1007/s43236-023-00661-9.