Research On HID Lamp Rectifying Effect

High Intensity Discharge (HID) Lamp is widely used in the field of roadway, square, workshop and other lighting area because of its high efficiency, long life, and good color rendering. However, Rectifying effect will appear in most HID lamps at the end of their lives. This will lead to overload in the ballast and relative components. Therefore, proper methods should be taken to protect the lighting system from being destroyed.Some fluorescent lamps with rectifying effect of different levels are found through observation of many fluorescent lamps which are at the end of their lives. Therefore, a new simulating experimental circuit is invented by the author according to the analysis of the rectifying effect waveforms and the mechanism of rectifying effect. Compared with the traditional simulating experimental circuit, the new simulating experimental circuit has the advantages of high accuracy, simple structure and convenient debugging. Also as the gas discharge lamps, HID lamps with rectifying effect can be studied with the aid of this.For further study of the rectifying effect, combining with the new simulating experimental circuit, the author discusses the influence of rectifying effect separately when the HID lamps are working with the ballasts of different topological structure. Also, the phenomenon of power exceeding is explained. Finally, the reasons of different phenomenon caused by rectifying effect are analyzed.Simultaneously, the HID lamp model is built by using the electrode modeling. The accuracy of this model is also confirmed by means of system simulation. Moreover, the starting characteristic models of HID lamps are built separately through the linear fitting method and the stepped curve fitting method. And then the model of rectifying effect is built according to the mechanism of rectifying effect. Then the system and starting characteristic simulations of rectifying effect are preceded. The influences caused by rectifying effect are interpreted preliminarily. The modeling of HID lamps with rectifying effect will play a crucial role for further study of rectifying effect on the impact of the lighting system and the popularization of the electronic ballast. To eliminate the impact of the lighting system caused by rectifying effect, the inspection and protection ways for this phenomenon are presented through the influence of rectifying effect. Then the experimental results prove the feasibility of this method. Finally, based on the control chip MC68HC908KX8, the 250W HPS lamps electronic ballast with anti-rectifying effect function is designed and the experimental results satisfy the design requirement.