Free fatty acids esterification catalyzed by acid Faujasite type zeolite Daniel Marcos Dal Pozzo, José Airton Azevedo dos Santos, Edward Seabra Júnior, Reginaldo Ferreira Santos, Armin Feiden, et al. Rsc Advances, 2019 FFA esterification pre-treatment catalyzed by a Faujasite type zeolite.
Dimmable flicker-free power LEDs lighting system based on a SEPIC rectifier using a regenerative snubber Ismael Burgardt, Eloi Agostini Junior, Carlos H. Illa Font, Claudinor B. Nascimento Iet Power Electronics, 2016 This study presents a universal‐input AC electronic lighting system using a non‐isolated SEPIC PFC rectifier to drive and control power light emitting diodes (LEDs). One energy regenerative snubber is proposed to reduce the converter switching losses aiming to improve the overall system efficiency. A linear current regulator is employed to provide the features of flicker‐free and dimming capability for the lighting system. The operation stages as well as the theoretical waveforms and main equations at steady state of the proposed SEPIC rectifier using the regenerative snubber are described in details. To reduce the efficiency impairment, the conditions for achieving minimum energy loss in the current regulator are also detailed. A control loop designed using the results from the small‐signal analysis presented in the study is proposed to track the optimal current regulator operating point in real‐time. Experimental results of a prototype operating from 90 to 265 V and output power from 15 to 100% for 35 LEDs / 42 W are presented to verify the analyses carried out.
