Single-Stage Led Drivers Based On Integrated Bcm Boost And Llc Converters For Street Lighting

• Main Author: Zawawi, Nurul Asikin
• Format: Thesis
• Language: English
• Published: 2017
• Subjects: T Technology; TK1-9971 Electrical engineering. Electronics. Nuclear engineering
• Online Access: http://eprints.usm.my/46439/1/Single-Stage%20Led%20Drivers%20Based%20On%20Integrated%20Bcm%20Boost%20And%20Llc%20Converters%20For%20Street%20Lighting.pdf; http://eprints.usm.my/46439/

Electrical lighting has been an important technology to modern society. Given the increasing concerns about environmental and energy saving issues, light-emitting-diode (LED) has become the research focus due to the features of mercury elimination and high energy efficiency compared to conventional lamps. Performance aspects of LED lighting are related with LED driver, thus an appropriate converter should be designed to power up the LEDs with good input power factor and high efficiency. To achieve these elements, single-stage alternating current to direct current (AC-DC) converter with power factor correction (PFC) is proposed as LED driver for application in street lighting. In this topology, a pair of boost circuits which share a single inductor are combined as a PFC stage and then integrated with half-bridge LLC resonant converter. Three kinds of rectifier circuits are proposed for the secondary-side rectification; full-wave bridge rectifier, full-wave voltage doubler rectifier and dual half-wave rectifiers. All rectifier circuits have their own advantages and remove the requirement of center-tapped transformer in circuit design. The power switches are driven by a high-voltage resonant controller IC L6598 with nearly 0.5 duty cycle and a small dead time. All proposed LED drivers have been tested in the laboratory for supplying 12 high-power LEDs from ac input voltage of 240-V. From the comparison results, LED driver using full-wave voltage doubler rectifier has shown the best performances, followed by LED driver using full-wave bridge rectifier and then LED driver using dual half-wave rectifiers. The highest power factor measured is almost unity at 0.99, the lowest total harmonic distortion (THD) is 13.8%, the highest efficiency is 93.39% and the lowest bus voltage is 330-V. The power factor correction was successfully achieved and high conversion efficiency was obtained due to soft-switching characteristics of the LED driver. The voltage stress on bus capacitor is considerably reduced to 1.36 times of the input-peak-voltage. The dimming capability was also accomplished. Lastly, the minimization of storage capacitance was successful with an acceptable range of output current ripple for flicker-less LED lighting.