Research On Automotive Headlamp Electronic Ballast Using Full-digital Controlled Mode

Xenon lamp is one kind of High Intensity discharge (HID) lamps, and it has the advantages of high stability, long life time and energy saving. Xenon lamp has been selected the most popular automotive headlamp right now, and its demand on market is keeping increasing. As a result, the research on automotive headlamp electronic ballast attracts many electrical engineers. Automotive headlamp electrical ballast has many control ideas, compared to the conventional analog and digital-analog control methods, full-digital control method has the highest flexibility, and it becomes the developing trend in this research area.Chapter 1 first gives the brief introduction about lighting and HID lamps, then introduce the physical and electrical characteristics of HID lamp. At the end of this chapter, the history, application status and developing trend of headlamp has been discussed. The important meaning of the thesis also has been given.Chapter 2 mainly gives some research result about HID electronic ballast including basic ballast topology, key problems of HID electronic ballast. The automotive headlamp electronic ballast is one kind of low-frequency square-wave HID electronic ballast, so this chapter pays more attention to low-frequency square-wave electronic ballast. Two-stage low-frequency square-wave electronic ballast has been included.Chapter 3 gives some research results about key technical problems about headlamp electronic ballast based on formal chapter's research results. These key technical problems are: the startup technical problems of xenon, the DC/DC converter, the igniter circuit and all kinds of control methods. Because full-digital control method has been chosen, the full-digital control technical has been discussed very carefully.Chapter 4 is the design process of all system parts, including hardware stage design, software stage design, parameter calculation of transformer and system waste calculation, control method of whole control process. By the implement of automotive headlamp electronic ballast prototype, experiment results have been given. These results show the rationality of the system design and do show full-digital control method has been successfully implemented.