Parameter Monitoring of High-Frequency Electronically Operated Discharge Lamp Systems

Abstract

Discharge lamps require high ignition voltage from typically one to several kilovolts for cold-start, but have low onstate voltage of typically 100 V. For discharge arc monitoring purposes, it is difficult or uneconomical to implement voltage sensor to cover such a wide range of voltage. In this paper, a nonintrusive and electrically isolated method, based on the single-sensor principle, is used to derive the system parameters and variables for system monitoring and control purposes. Unlike the traditional resistive potential divider for voltage feedback, the proposed method is nondissipative. Only one coupled winding is used to derive the converter inductor voltage, from which the lamp power, lamp arc resistance and inverter dc link voltage can be accurately derived. The proposal is verified with good agreement between derived values and measurements in an electronic ballast-fluorescent lamp system. The proposal can be useful in applications in which sensing the voltage across the load is either difficult or costly.

Realization of an dimmable electronic ballast for a discharge lamps fed by an LSCSCP circuit and a PFC stage

“…It is widely acknowledged that the variation of the power of discharge lamps can be done in two different ways, namely through the variation of the frequency or else through the variation of the DC voltage applied at the input of the inverter. In recent past, a number of researchers [24], [25] have carried out a comparison between the two methods and found out that the second one is more advantageous as it allows having a more linear operation of the lamp.…”