A very simple control strategy for power factor correctors driving high-brightness light-emitting diodes

• Published in: 2008 Twenty-Third Annual IEEE Applied Power Electronics Conference and Exposition pp. 537 - 543
• Main Authors: Sebastian, J., Lamar, D.G., Arias, M., Rodriguez, M., Hernando, M.M.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.02.2008
• Subjects: Circuits; Feedback loop; Light emitting diodes; Lighting control; Power supplies; Pulse width modulation; Pulse width modulation converters; Reactive power; Switching converters; Voltage control
• ISBN: 9781424418732; 1424418739
• ISSN: 1048-2334; 2470-6647
• DOI: 10.1109/APEC.2008.4522773

This paper presents a new control strategy for Power Factor Correctors (PFCs) used to drive High-Brightness Light- Emitting Diodes (HB-LEDs). This control strategy is extremely simple and it is based on the use of a conventional peak current- mode controller with a suitable selection of the compensation ramp waveform. In these conditions, an almost perfect sinusoidal line current is obtained at full load in the case of a topology based on the Boost converter. If the converter belongs to the Flyback family (Flyback, Buck-Boost, SEPIC, Cuk and Zeta), the line waveform appears notably distorted if the compensation ramp is a linear ramp, but becomes almost sinusoidal if the linear ramp is substituted by a properly chosen exponential waveform. The line waveform is slightly distorted when dimming control is implemented or when the converter works in either over-voltage or under-voltage conditions. However, the waveform maintains a very high Power Factor even in these conditions. Moreover, the line current is cycle-by-cycle controlled due to the peak current- mode control and, therefore, the input current feedback loop is extremely fast, thereby allowing this type of control to be used with high frequency lines (above 400 Hz).