The Key Technologies Of Metal Halide Lamp Electronic Ballasts

Because of the shortage of non-renewable energy, energy saving has become a worldwide topic. Being part of it, green lighting projects are attracting more and more attention. The High-Intensity-Discharge Lamps (HID) are notable for their high luminous efficacy, good color rendering, and long life. Metal halide lamps (MHL) have the best combination of the above properties and are considered the most ideal light sources. Therefore the development of the drive circuit of the lamp, namely ballast has become an important research point. Because of the excellence in energy saving, light weight, etc., electronic ballast will gradually take the place of traditional electromagnetic (EM) ballast.At the beginning of the thesis, the development process of ballast is presented and the operation principles of discharge lamp as well as the ballast are introduced. Experimental comparison between EM ballast and electronic ballast is conducted to analyze the advantage and disadvantage of each of them.Based on the basic functions of electronic ballast and the start-up characteristics of the HID lamps, different topologies, power control methods and start-up circuits were introduced one by one. And comparative results were given out in the last of each chapter.Finally the design process of a three -stage ballast and a two-stage ballast for 70W ceramic metal halide lamp was presented. Experimental results were given out to verify the theory before.