A Study On Key Technology Of Electronic Ballast For High Intensity Discharge Lamps

Because of the shortage of non-renewable energy,energy saving has become a world-wide topic. Being part of it,green lighting projects are attracting more and more attention. As a high efficacy long life time lighting source,High Intensity Discharge (HID) lamp plays an important role in it. 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 operation principles of HID 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.Acoustic resonance is a serious problem of the HID lamps when operating under highfrequency. Chapter n investigates the mechanism of acoustic resonance,its effects and itscharacteristics. All kinds of methods to eliminate acoustic resonance are introduced and analyzed by theory and experiments.Voltage source half bridge resonant ballast are widely used because of its simple control strategy and easy starting. Detail design process of a 380V/250W ballast for High PressureSodium lamp is given in Chapter M. It's verified by simulation and experiment.Easy to dim is a superiority of electronic ballast to EM ballast and the lamp should be dimmed in many circumstances due to different intentions. Chapter IV summarizes all kindsof dimming methods and studies the characteristic of the lamp under dimming. Experimental results of variable switching frequency scheme and variable voltage scheme are provided to analyze their strongpoint and drawbacks. A novel dimming method is also proposed in this chapter with verification of simulation and experiment.At the end of the paper,a novel two-stage low frequency square wave electronic ballast for HID lamps is proposed with detail design process. Simulation and experimental results are provided to verify its superiority.