Arguments for increased efficiency of a Xe excimer DBD by pulsed instead of sinusoidal excitation

Transcription

1 Arguments for increased efficiency of a Xe excimer DBD by pulsed instead of sinusoidal excitation Mark Paravia, Michael Meisser, Klaus Trampert, Wolfgang Heering Light Technology Institute University Karlsruhe 1/16/28 M.Paravia, GEC 28, 1/16/28, p. 1

2 Introduction Dielectric Barrier Discharge plane gas discharge Xenon excimer nonequilibrium plasma Efficiency gain due to pulsed instead of sinusoidal excitation [1] plasma efficiency up to 65 % [2] [1] Mildren, Carman, J. Phys. D: Appl. Phys. 34 (21) [2] Vollkommer, Hitzschke, US56441A (1994) M.Paravia, GEC 28, 1/16/28, p. 2

3 Outline 1. Experimental setup 2. Sinusoidal and pulsed excitation 3. Separation of energies 4. Conclusion M.Paravia, GEC 28, 1/16/28, p. 3

4 Experimental setup glass plate glass solder electrode gas gap spacer Measurements: lamp luminance L time resolved NIR emission (823 nm, 828 nm) external and internal electrical values gas gap: 2 mm xenon: 125 mbar active area: 5 cm² frequency: 4 khz v lamp(max) : kv M.Paravia, GEC 28, 1/16/28, p. 4

5 Internal values i lamp v lamp plasma barrier v C gap C barrier i blind i plasma z plasma v measurement of internal values: analogue measurement of plasma current plasma power without blind component Roth, M., Neiger, M., 21. IDRC, Nagoya, 21, p M.Paravia, GEC 28, 1/16/28, p. 5

6 Experimental setup 15 sinusoidal 15 pulsed lamp voltage/v 5-5 lamp voltage/v time/µs Electrical excitation 1. sinusoidal ECG resonant pulse ECG with variable pulse length time/µs M.Paravia, GEC 28, 1/16/28, p. 6

7 Sinusoidal excitation voltage/v ignition glow phase 823 nm 828 nm p plasma sinusoidal v lamp plasma power density/w/cm² NIR/a.u. sinusoidal excitation: one ignition per half-wave glow phase after ignition power consumption during glow phase filaments still burning 5 1 time/µs f = 4 khz, v lamp : = 93 Vrms, P = 33 mw/cm², η = 19 lm/w M.Paravia, GEC 28, 1/16/28, p. 7

8 Pulsed excitation 2 ignitionglow phase pulsed 15 pulsed excitation voltage/v p plasma 823 nm 828 nm v lamp plasma power density/w/cm² NIR/a.u. first and second ignition per pulse short glow phase after ignition discharge still burning during glow phase time/µs -15 f = 4 khz, pulse length 2.8 µs, P = 64 mw/cm², η = 17 lm/w M.Paravia, GEC 28, 1/16/28, p. 8

9 Pulsed excitation voltage/v t pulse = 2.1 µs t pulse = 2.8 µs time/µs pulsed excitation variation of pulse length pulse length.6 µs to 5.1 µs constant pulse shape V lamp(max) = kv 1.8 t pulse = 2.1 µs t pulse = 2.8 µs IR/a.u time/µs M.Paravia, GEC 28, 1/16/28, p. 9

10 Pulsed excitation luminace/cd/m² pulse length/µs power density/mw/cm² 4 2 luminance power η pulse length/µs lamp efficiency/lm/w pulse length/µs pulsed excitation luminance up to 3 cd/m² for t pulse =.6µs lamp efficiency rising up to 3 lm/w power density P = 5-62 mw/cm² M.Paravia, GEC 28, 1/16/28, p. 1

11 Separation of energies 2 CDI-5 Füllung 4 - Pplasma x plasma power power density/w/cm² density/w/cm² 1 plasma power plasma energy 1. Ignition 2. Ignition plasma energy energy density/j/cm² time/s time/µs x 1-6 Ignition phase: excitation of Xe* and Xe** generation of VUV radiation glow phase: Xe + heating, negligible generation of Xe*, Xe** Simplification: no VUV radiation is generated M.Paravia, GEC 28, 1/16/28, p. 11

12 Separation of energies energy density/nj/cm² E total energy density/nj/cm² pulsed ElampE lamp E total Eplasma E ignition sinusoidal f = 4 khz 2 E Ignition =E 1.Ignition +E 2. Ignition Separation of energy: t pulse ignition energy rises with decreasing t pulse ratio of ignition energy to total lamp energy depends on pulse length M.Paravia, GEC 28, 1/16/28, p. 12

13 Separation of energies Luminance/cd/m² pulsed Lumiance rlo E igntion L E ignition Eplasma sinusoidal f = 4 khz Eigntion/nJ/cm² Eigntion/nJ/cm² lamp efficiency/lm/w pulsed efficiency lamp P_ignition/P_a E igntion /EE total lamp sinusoidal f = 4 khz η E ignition /E total Eigntion/Elamp t pulse /µs t pulse /µs. good correlation between light and ignition energy: high efficient excitation during ignition losses during glow phase Conclusion: reduce glow phase energy by short pulses M.Paravia, GEC 28, 1/16/28, p. 13

14 Summary Compared sinusoidal and pulsed excitation Separation into ignition and glow phase Correlation: L E ignition η E ignition /E total High efficiency due to reduction of glow phase losses M.Paravia, GEC 28, 1/16/28, p. 14

15 GEC 28 Thank you for your attention. M.Paravia, GEC 28, 1/16/28, p. 15