An investigation into new control methods for electronic ballasts

Abstract

Nowadays, fluorescent lamps have become the most favored lighting sources in many applications. In this thesis, a new Universal High Frequency Electronic Ballast design is presented. With the new design, a single electronic ballast design can be used for fluorescent lamps of different power levels. As a result, damage caused by power mismatch of fluorescent lamp or electronic ballast can be prevented. A high frequency electronic ballast design with the capability of low radiated and conducted EMI over a wide dimming range is also described in this thesis. This ballast overcomes some limitations of traditional electronic ballasts that use frequency variation for dimming control. It allows the lamp power to be controlled from 100% to less than 10%. This thesis also reviews the various circuit topologies used in modern electronic ballast designs. An improved mathematical modeling technique for electronic ballast design has been developed for the optimum serial resonant tank network components. Using such modeling method as a simulation tools, development time of the electronic ballast can be shortened. Note: Part of the materials of this thesis (Chapter 6) has appeared in the IEEE transactions on P.E. [66]. A copy of the paper is included in the appendix. A U.S. patent on the control method described in Chapter 5 has also been filed [67].