LIGHT emitting diodes, ALTERNATING currents, ELECTRIC current regulators, ELECTRIC current converters, PULSE width modulation, ELECTRIC resistors, ELECTRICAL engineering, and MICROFABRICATION
A compact-size and high-conversion-efficiency regulator used to stabilize the luminous flux of alternating-current-operated light-emitting diodes (ACOLEDs) is proposed. The presented regulator is composed of a full-bridge rectifier and a power switch to supply directly from ac power source for the ACOLEDs without any ac/dc converter. Commonly adopted pulsewidth modulation techniques are utilized to regulate the input power fed into ACOLEDs. Design guidelines and experimental results of the prototyping regulator for an 8-W ACOLED operating under different input ac voltages (110 \pm 10\ \Vrms, 60 Hz) are provided. According to the experimental results, the advantages of the proposed regulator include simplified design, compact size, high conversion efficiency, and low cost. Since no magnetic component is required in the presented system, therefore, it can easily be fabricated into the same ACOLED chip in the future. [ABSTRACT FROM AUTHOR]
Karimi, Shahram, Gaillard, Arnaud, Poure, Philippe, and Saadate, Shahrokh
IEEE Transactions on Industrial Electronics. Dec2008, Vol. 55 Issue 12, p4299-4308. 10p. 4 Black and White Photographs, 5 Charts, 17 Graphs.
WIND power, ELECTRIC current converters, WIND energy conversion systems, FIELD programmable gate arrays, ELECTRIC machinery, and POWER electronics
This paper discusses the design, implementation, experimental validation, and performances of a field-programmable gate array (FPGA)-based real-time power converter failure diagnosis for three-leg fault tolerant converter topologies used in wind energy conversion systems (WECSs). The developed approach minimizes the time interval between the fault occurrence and its diagnosis. We demonstrated the possibility to detect a faulty switch in less than 10 μs by using a diagnosis simultaneously based on a "time criterion" and a "voltage criterion." To attain such a short detection time, an FPGA fully digital implementation is used. The performances of the proposed FPGA -based fault detection method are evaluated for a new fault tolerant back-to-back converter topology suited for WECS with doubly fed induction generator (DFIG). We examine the failure diagnosis method and the response of the WECS when one of the power switches of the fault tolerant back-to-back converter is faulty. The experimental failure diagnosis implementation based on "FPGA in the loop" hardware prototyping verifies the performances of the fault tolerant WECS with DFIG. [ABSTRACT FROM AUTHOR]