Square-Shape Current-Mode Supply for Parametric Control of the DBD Excilamp Power

Abstract

With the aim of providing a power supply for the study of dielectric barrier discharge (DBD) excimer lamps (excilamps), a current-mode converter that allows for an accurate adjustment of the electrical power injected into one of those lamps is designed and implemented. Starting from the electrical model of the DBD lamps, the convenience of using a current-mode supply to control the lamp power is demonstrated. With the proposed converter, the current supplied to the lamp has a trapezoidal almost-square shape controlled by means of three parameters, namely, amplitude, duty cycle, and frequency, which provides full control of the lamp electrical power. Implementation is made considering a step-up transformer interfacing the high-voltage lamp with the converter. Experiments demonstrate the operating principle of this converter, including ultraviolet power measurements for a DBD XeCl excilamp. The capabilities of the converter are used to analyze the lamp behavior under different combinations of these three parameters, illustrating its capabilities for finding the optimal operating point of a DBD reactor.Index Terms-Current control, dielectric, dielectric barrier discharge (DBD), excimer lamp (excilamp), ultraviolet (UV).

Optimizing the Operation of DBD Excilamps

“…As proposed in [19], this current 0093-3813 © 2016 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission.…”

“…A detailed study concerning the design and operation of this DBD power supply topology can be found in [19] and [20].…”

Parametric study of dielectric barrier discharge excimer UV lamps supplied with controlled square current pulses

“…All the bulbs are filled with the same Xe-Cl mixture, with the same pressure. According to the classical model [5], based on the electrical equivalent circuit (Figure 1-c), the electrical properties of each bulb can be derived: the parameters of this model are: Cg and Cd, the capacitances of the gas gap and of the quartz walls (series connected), and Vth, the threshold voltage, i.e. the minimum value of the gas voltage required to turn on the plasma.…”

“…The power supply which has been selected to carry out the experiments is a square shape current source (the topology is presented on Figure 2[5], together with the main equations), already detailed in [5]: it presents a cascaded structure, associating a DC current source with a current inverter, aimed at controlling the shape of the square current pulses. Its main advantage is the availability of 3 independent degrees of freedom (DOF) to control the ilamp current pulses injected into the bulb: their magnitude I, their frequency f, and their duty cycle D, or their duration D/2f, as shown on 4.…”

“…The applicability of these DBD excilamps has been demonstrated; today, studies are oriented toward the improvement of their performance. This can be achieved by means of the bulb design (geometry, filling mixture, pressure and materials) [2], [3] and also by selecting the most performing electrical operating conditions [4], [5].These both optimization paths are the purpose of this paper: the characteristics of the candidate bulbs, which performances will be experimentally compared, are presented in §2 and an estimation of the parameters of their equivalent circuit model is displayed. Associated to this set of lamps, the selected power supply, by means of a square shape current source generator is presented in §3: the operating principles of this topology, together with its performances are presented; elements for the design of the actual generator, specifically developed for this study are also proposed.…”