Design Of Electronic Ballasts For High Intensity Discharge Lamps

High Intensity Discharge(HID) lamps are high-efficient light sources, which arewidely used in commonality and street lighting applications.To work properly, HID lamps need special current restraining circuit, which iscalled "Ballast". The Ballast restrains the lamp current and makes it work undernormal electrical characteristic. Now HID lamps are generally ignited by thetraditional 50Hz electromagnetic ballast that bears limitations like high energyconsumption, low efficiency and low power factor, etc. Therefore, researchers andexperts world-wide are strenuously working to develop the electronic ballast of HIDlamps.This Paper firstly introduced the principles of high intensity discharging and theelectrical characteristic of HID lamps, pointed out the demand to electronic ballasts.Then the paper analyzed the pop-topics and critical techniques of HID andsummarized the excellent fruits that obtained before. In the end we designed differentelectronic ballasts for High Pressure Sodium (HPS) lamps and Metal Halide (MHD)lamps.Finally, the paper discussed the Electromagnetic Interference (EMI) and thereliability of Ballasts, established the circuit models for conducted EMI and analyzedthe factors the may impact the reliability.