Discharge Lamp Electronic Ballasts

The electrodeless fluorescent lamp was new product explored in the 1990'last century. Compared with the traditional fluorescent lamp, because of long life, high light efficiency, green and environment protection, the electrodeless fluorescent lamps, which had bright future of great market, were accepted with public and road illumination. Furthermore, researchers and experts world-wide were strenuously working to develop electrodeless lamps and relevant electronic ballasts. But due to the cost, electro magnetic interference (EMI), heat elimination and so on, electrodeless lamps were not prevalent in lighting applications for its reliability and acoustic resonances.This paper firstly introduced the background and status at home and abroad of electrodeless lamps. Based on the principles of the lamps and the relevant literature, built the transformer model of electrodeless lamps and through circuit equivalent, acquired L-R circuit model. Combined with half-bridge inverter, the paper analyzed the circuit character of reactive and capacitive load. Since the electrodeless lamps work at very high frequency, so as to be hard to find the relevant IC (integrated circuit) to drive half bridge inverter, the paper introduced some driver schemes and tested the corresponding IC. Through analyses of LC resonant tank, the discriminance of load character and design approaches of LC parameters were given, which put the theoretic base for the rear experiment.Considering the high cost of electrodeless lamps, the paper presented a single-stage single-switch electronic ballast topology through the integration of a buck power-factor-correction (PFC) and class E resonant inverter with only one power switch to save switches and control circuits, to simplify the circuit structure. In the fourth chapter, Pspice simulation, including fluorescent lamps model and electrodeless lamps model, proved to be in consistence with theoretic analysis and could be content with IEC 16000 class c standard.Finally, based on the former mentioned designing method, a electronic ballast was developed for the 23W electrodeless lamp. Designing process in detail were given in the paper, including EMI circuit, half-bridge resonant inverter circuit, driver circuit composed of NE555 and IR2111. Experimental waveform proved the validity of the model for electrodeless lamps.