Redução de harmônicos de corrente em sistemas de iluminação à LEDs dimerizáveis

Abstract

The present study proposes solutions to reduce the current harmonics from a dimmable LED illumination system. The purpose is to find an efficient and cheap way to considerably reduce those. It begins with a theoretical fundament about non-linear loads, as well as the operation of the TRIAC device, the component responsible for the switching of alternating current in a circuit. Afterwards it mentions the effect of harmonics in electrical systems, besides indicators and ways of adapting it within standards placed by norms and international recommendations. The application of some mathematical equations is performed as a development of a filter project, considering the physical volume, the efficiency in reducing the harmonics, beyond the economic viability. Computer simulations of the proposed circuits are also performed, followed by the practical implementation in order to prove the theory and check if the harmonic distortion index is within acceptable standards. Judging by the implementation results, the second order low pass filter was the most efficient on the current harmonics reduction. Both of the filters turned the circuit power factors considerably worse, becoming with a capacitive circuit characteristics. In order words, both of the filters made the delayed tension in about 90° regarding the current.