Ferroelectric capacitors for discharge lamp ballast circuits

Abstract

Abstract Discharge-lamp ballast circuits of the type commonly used in the USA utilize an organic ballast capacitor. We have shown that substituting a ferroelectric ceramic capacitor with its dielectric nonlinearity improves the performance of the ballast circuit. Fluorescent and other discharge lamps operate more efficiently, and the ballast transformer circuit power losses are reduced. We will show that the ballast related characteristics of such nonlinear capacitors can be described by six parameters of an equation which represents the nonlinearities as well as hysteresis. A high-precision computer simulation was used to optimize the ballast-capacitor combination and find the shape of optimum nonlinearities. A tolerance study was also performed on the capacitor parameters. Extensive in-circuit testing of several different materials was used to define system and material requirements.