Research And Design Of Electronic Ballasts For High Pressure Sodium Lamps

With the development of economy and society, the problems of energy shortage and environmental pollution have become increasingly prominent, and green lighting has become the pursuit of goals. As the third generation of the electric light, High Intensity Discharge (HID) has the advantages of high light efficiency, long life and good light color, it is widely used in traffic lighting systems and industrial lighting systems. Because the inductive ballast has so much shortcomings, the high-performance HID electronic ballast is becoming a hot topic, and will eventually replace the inductive ballast.In many kinds of HID lamps, High Pressure Sodium(HPS) is the most widely used. Therefore, this thesis is armed at researching and designing the electronic ballast of400W HPS lamps.This thesis researches and develops the working principles of the HPS lamps based on the operating characteristics of the HPS lamps. According to the basic principles, the key hardware circuits were designed, including the EMI filter circuit, active power factor correction (APFC) circuit, inverter and start circuit and so on. In this thesis, the EMI filter circuit is based on double-π-type structure, the APFC circuit uses BOOST type circuit topology, the inverter circuit is the half bridge inverter circuit structure, and startup mode uses the pulse start mode, the control circuit uses the digital control chip as the core.The thesis researches the acoustic resonance suppression technology and dimming function. The acoustic resonator is the special characteristics when HPS lamps working in the high-frequency state, it seriously affects the normal work of HPS lamps and electronic ballasts. The subject solves the problem of acoustic resonance through using the adjustment phase modulation technology, ensures normal stable operation of the HPS lamps. The dimming function is a major advantage of the electronic ballast, it can further save energy. The electronic ballast uses the FM dimming technology and achieves the timming dimming and external control dimming function. Based on the above studies, the project successful designed a400W HPS electronic ballast and a dimming type400W HPS electronic ballast. After industrialization experimental verification, the designed electronic ballast has high power factor, high efficiency, low harmonic distortion rate, without acoustic resonator, dimmable, stable and reliable features, successfully achieve the desired objectives.