| Summary: | 碩士 === 國立臺灣科技大學 === 電子工程系 === 98 === This project focuses on the study and implementation of a high-efficiency, high power factor (PF) driver for LED street lamps. The main power circuit is composed of a front-stage active power factor corrector (PFC) and a half-bridge (HB) DC-to-DC series resonant converter (SRC). Both the fixed-frequency average current mode control and the varying-frequency peak current mode control for the PFC are utilized to reduce the input current harmonics and force the input current to be in phase with the source voltage. Therefore, a high PF can be achieved. An SRC control IC is adopted to reduce the switching loss with zero-voltage turn-on of the high- and low-side MOSFET switches. The secondary-side synchronous rectification (SR) replaces a diode with an MOSFET switch to reduce the conduction loss at heavy loads. Two drivers for the LED street lamps are implemented and tested with an input voltage of 90 to 260 Vrms/60 Hz, a DC output voltage of 34 V and an output power of 200 W. The implemented LED drivers also feature constant voltage control, constant current control, start-up and auxiliary powers, over-voltage and over-current protections.
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