Análise e projeto de uma topologia de dois estágios otimizada aplicada à iluminação pública com leds

Abstract

This work presents the analysis and implementation of a connection between two power converters, applied to street lighting with LEDs. This connection is called optimized cascade. The main idea of this connection is the reduction of the processed energy by the second converter, increasing this way the system efficiency. Besides that, the electrolytic capacitor is eliminated, aiming the life-span increase of the converter. To do that, the capacitance is reduced, causing a low frequency ripple, which is compensated by the second converter. This way, it is possible to unify high eficiency with long life-span on this converter. Such characteristics are considered fundamentals on LED driver. To prove the idea, two prototypes were built, one based on feedback control scheme and the other on a feedback plus feedforward control scheme. Both had shown good results, however the feedback plus feedforward controller proved to be more effiective on the active compensation of the low frequency ripple. In the end, a comparison between the two most used topologies on LED driver with the optimized cascade was performed. The results had shown a possible application range, advantages e limitations of this idea.