| Summary: | 碩士 === 義守大學 === 電機工程研究所 === 83 === In this thesis, the design problem of electric ballast for fluorescent lamp is considered. The proposed electric ballast is operated at high frequency and consists of two parts. The first part is a half bridge rectifier. It performs AC-to-DC conversion and doubles the voltage. Via pulse width modulation, the DC voltage is fed into the second part, a series resonant inverter. The inverter is most important in the design of electric ballast. It provides the starting high voltage to turn on the lamp and then stabilizes the lamp current at steady state. In addition, the relationship among the switching frequency, duty cycle, lamp starting voltage, crest factor and the corresponding component values are discussed mathematically. The design procedures of electric ballast are thus outlined. This is one of the main contribution of this thesis. Finally, the electric ballast for a 40-watt lamp is practically implemented. Experimental results are given to indicate that there is no flicker, the power efficiency is increased about 14%, and the lamp light output is adjustable form 500Lux to 3200Lux.
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