| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 9.05 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
O uso de lĂąmpadas LEDs de corrente alternada (CA) Ă© considerada uma boa solução para a sistemas de iluminação. Algumas caracterĂsticas como alta queda de tensĂŁo e uma baixa corrente de transmissĂŁo atravĂ©s de uma resistĂȘncia, permite que os LEDs CA sejam conectados diretamente a uma fonte. Entretanto o LED produz uma alta distorção harmĂŽnica na corrente de entrada, nĂŁo cumprindo os requisitos exigidos pela norma IEC 61000-2-3 classe C. O objetivo deste trabalho Ă© a apresentação de um sistema de potĂȘncia eletrĂŽnica com correção do fator de potĂȘncia (PFC) para alimentar as lĂąmpadas LED CA. O conversor SEPIC operando em MCD Ă© responsĂĄvel pela correção do fator de potĂȘncia e a regulação do barramento CC. A alimentação em corrente alternada Ă© feita pelo inversor Half-Bridge onde os mosfets sĂŁo comandados atravĂ©s de uma modulação com pulsos assimĂ©tricos, como por exemplo: a modulação I-LFSQW (Low Frequency Square Wave Current). De forma alternativa ao estudo do conversor SEPIC MCD sĂŁo estudados os conversores SEPIC MCCr (Modo de Condução CrĂtica) e Boost MCCr, para a correção de fator de potĂȘncia e regulação do barramento CC.
The use of LEDs that operate on alternating current (AC) has been considered a good solution for lighting system applications. With high direct breakdown voltage and lower driving current through a resistor element, the AC LED can be connected directly to a supply source. However, this produces a high harmonic distortion in the input current, not meeting with the requirements of the IEC 61000-2-3-class C Standard. This way, this thesis presents a power electronic system with Power Factor Correction (PFC) to drive AC power LEDs. The PFC and the DC bus voltage regulation is carried out by a SEPIC converter operating on DCM (Discontinuous Conduction Mode). AC power is supplied by the Half-Bridge Voltage Inverter operation with asymmetric command pulses, i.e., using ILFSQW (Low Frequency Square Wave Current) technique. As an alternative to the SEPIC DCM, the SEPIC BCM (Boundary Conduction Mode) and Boost BCM rectifiers are studied to PFC and DC bus regulation.
The use of LEDs that operate on alternating current (AC) has been considered a good solution for lighting system applications. With high direct breakdown voltage and lower driving current through a resistor element, the AC LED can be connected directly to a supply source. However, this produces a high harmonic distortion in the input current, not meeting with the requirements of the IEC 61000-2-3-class C Standard. This way, this thesis presents a power electronic system with Power Factor Correction (PFC) to drive AC power LEDs. The PFC and the DC bus voltage regulation is carried out by a SEPIC converter operating on DCM (Discontinuous Conduction Mode). AC power is supplied by the Half-Bridge Voltage Inverter operation with asymmetric command pulses, i.e., using ILFSQW (Low Frequency Square Wave Current) technique. As an alternative to the SEPIC DCM, the SEPIC BCM (Boundary Conduction Mode) and Boost BCM rectifiers are studied to PFC and DC bus regulation.
Description
Keywords
Correção do Fator de PotĂȘncia SEPIC Modo de Condução Descontinuo LEDs Inversor de FrequĂȘncia Power Factor Correction Discontinuous Conduction Mode Inverter