Research On Critical Technique Of Electronic Ballast For Gas Discharge Lamp

As green lighting project has started in 1996, gas discharge lamp such as: fluorescent lamps high pressure sodium lamps metal halide lamps, which presents respective characteristic, have been used in many applications including: home lighting, outdoor lighting and automotive lighting. However, traditional electromagnetic ballasts for these gas discharge lamps cannot satisfy the demand of modern lighting system, due to their drawback including large size, heavy weight, low power factor, flicker, poor power regulation and sensitive to line-voltage dips. As the new efficient lighting electrical appliance, electronic ballast is the critical issue in the green lighting project. From technique, the research of electronic ballast belongs to the field of power electronic ballast. Because of the research object limitation, not more attention had been paid to the development of electronic ballast. With the developing of power electronic semiconductor and control technique, the technologies of electronic ballast are developing at the same time. This dissertation combines the basic characteristic of discharge lamps and aim at the critical technology of their electronic ballast. The study of this subject is of important meaning in theory and the proposed methods also have practical values.After reading a lot of recent published papers, several basic problem of electric ballast such as lamp modeling, resonant converter topology and power factor correction have been reviewed and summarized firstly. Then, some important research topics such as the self-adaptable control of electronic ballast intelligence and network of digital lighting system electronic ballast for new generation lighting source are introduced. The most recent research achievements in this field are reported. The content of this section has important value for studying of electronic ballast.Self-oscillating control technology for fluorescent lamp ballast is a difficult topic because of the nonlinear control characteristic. This paper presents a time domain analysis method. After deducing the mathematical expression of resonant voltage and current under different stimulus, the precise relationship between switching frequency and self-oscillating circuit is obtained. Compared with frequency domain analysis method, proposed method has more accuracy. Considering the parasite capacitor of MOSFET, the proposed method is amended further. A self-oscillating electronic ballast prototype for 36W linear fluorescent lamp is designed ant tested. Experimental results show that the accuracy of amended method is satisfying, which is very useful in the design of self-oscillating electronic ballast.Based on the introduction of basic characteristic of general metal halide lamp, this paper study the critical technology of its ballast such as basic topology start-up and steady control technology. The specific definition of ignitor pulse is put forward. Two approximate equivalent models are used to analyze the influence of ignitor circuit. Anelectronic ballast prototype for 70W metal halide lamp is designed ant tested. Experimental results show that the start-up performance of metal halide lamp not only has relation with ignitor pulse's width and height but with its frequency. By designing ignitor circuit properly, the glow discharge period during lamp start-up can be shortened, resulting in good start-up performance.After the previous research on electronic ballast, this dissertation investigates the ballast technique of a new type ultra-high pressure gas discharge lamp-xeon metal halide lamp (XMHL) used in automotive headlight application. The basic function of its electronic ballast is presented based on the introduction of lamp characteristic. After analyzing the DC/DC technology of its ballast, two methods are presented to prolong the lamp life. The first method is start-up control technology including current auxiliary circuit and DC lighting. With this method, the lamp will not extinguish or operate at glow discharge for long time. So the lamp can be started once and softly res...