A Double-Loop Primary-Side Control Structure for HB-LED Power Regulation
| Autor: | Mehrdad Moallem, Ali Shagerdmootaab |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
010302 applied physics
Engineering Switched-mode power supply Flyback converter business.industry 020208 electrical & electronic engineering 02 engineering and technology Power factor LED circuit 01 natural sciences Constant power circuit Control theory 0103 physical sciences 0202 electrical engineering electronic engineering information engineering Constant current Electrical and Electronic Engineering business Power control |
| Zdroj: | IEEE Transactions on Power Electronics. 31:2476-2484 |
| ISSN: | 1941-0107 0885-8993 |
| DOI: | 10.1109/tpel.2015.2434994 |
| Popis: | This paper presents a study of high-brightness LED (HB-LED) strings under power drive control, in which the LED's input power is controlled rather than its current. In the conventional constant current drive technique, any changes in the LED string's forward voltage results in output light variations due to a strong dependence between the LED output light to its input power. Under constant power drive control, the LED string's forward voltage variations due to ambient temperature changes and aging are compensated. To evaluate the power drive control method, an inner–outer-loop control structure is developed by utilizing an ac–dc flyback converter. To this end, a primary-side LED power estimator and controller are proposed to achieve simultaneous output power regulation and input power factor correction. An expression is obtained for the LED power in terms of its input current and ambient temperature that can provide qualitative and quantitative behavior in constant-current and constant-power drive regimes. Experimental results using a Cree CR22-32L LED string are presented and compared with the constant current drive technique for temperature variations in the range 25–80 $^\circ$ C. For the aforementioned temperature range and using similar hardware, the proposed controller results in an 8% reduction of the LED output light when compared to a 13% reduction using the constant current drive technique. |
| Databáze: | OpenAIRE |
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