Electronic Ballast For Metal Halide Lamps Based On MCU Control

With the development of society, people's requirements for light source are increasing continuously. The metal halide lamps (MHL) have not only the characteristics of high luminous efficacy, high luminance, and long life as other HID lamps, but also have the characteristic of good color rendering. Therefore, metal halide lamp is a kind of electric light source with fairly ascendant performance. It has a long-range developmental future.For the widely applications of metal halide lamp in the luminous field, the needs of ballast used for metal halide lamp (MHL) are increasing constantly. Conventional inductance type ballast will be washed out as its so many disadvantages, so electronic ballasts are taking the dominant status in ballast market gradually. In order to overcome some problems in analog control, digital control is becoming a hotspot in the research field of electronic ballast.Firstly, different electric light source are classified and compared, HID lamps especially.The MHL's excellences are summarized, the condition of electronic ballast market are also analyzed. Secondly, the lighting principle of metal halide lamps and the start-up process of MHL is achieved based on the discussion of gas discharge elements and gas discharge C-V characteristic.Thirdly, the thesis synthetically researches the realization scheme of electronic ballast used for MHL by the technical lays of basic topology, control strategy, method for free of acoustic resonance, ignition circuit.Finally, the design process of three stage and two stage electronic ballast used for 250W MHL are introduced. Two prototypes for 250W metal halide lamps are presented, and the experimental results are displayed.