Resonance behaviour of a pulsed electronic control gear

KIT – University of the State of Baden-Wuerttemberg and National Research Center of the Helmholtz Association

Light Technology Institute [LTI], Department of Electrical Engineering and Information Technology

www.kit.edu

Resonance Behaviour of a Pulsed Electronic Control Gear for Dielectric Barrier Discharges

Michael Meisser, Mark Paravia, Wolfgang Heering, Rainer Kling

Light Technology Institute (LTI)2 26.04.2010 Dipl.-Ing. Michael Meisser, PEMD 2010: “Resonance Behaviour of a Pulsed Electronic Control Gear for Dielectric Barrier Discharges”

Dielectric Barrier Discharge Lamps - DBD

coaxial type plane to plane type

applications:

UV - surface modification, lacquer curing

scanner and copying machines e.g. XeFITM (OSRAM, Germany)

ambient lighting

features:

instant-on

long lifetime

areal radiation

various wavelengths

mercury free

Planilum© (Saint-Gobain Glass, France)Xeradex® (OSRAM, Germany)


Dielectric Barrier Discharge Lamps – Set-up

plane to plane type

Characterization:

low power factor – capacitive loads

Requirements:

high AC voltage

pulsed operation

energy recovery


0 5 10 15 20 25 30-2000

-1500

-1000

-500

0

500

1000

1500

2000

vlamp

vla

mp [

V]

time [µs]

Pulsed Operation Mode With Resonant ECG

3 half-wave sinusoidal pulse lamp operation

one lamp ignition per half-wave

fpulse ≈ 200 kHz, frep = 32 kHz


Schematic and Operation Mode

HS

LS

L

Tr

CDC

Vs

D1 D2

ClampDBD

Lm

LsIL

VlampVLS

VL VCDC

CLS

resonant tank excited by half-bridge

waveforms resulting from step answer of RLC-circuit

Paravia, M. et al "Threshold current density for homogeneous excitation of pulsed xenon excimer DBD.“ Int. Conf. on Plasma Science, ICOPS, 2008


10 20 30 40 50 60 70 80 90-2000

-1000

0

1000

2000

time [µs]

vla

mp [

V]

10 20 30 40 50 60 70 80 90-20

-10

0

10

20

i la

mp [

A]

Problem of Parasitic Parallel Resonance

magnetic runaway of magnetic components

peak currents may destruct half-bridge

excessive v-t products


HS

LS

L

Tr

CDC

Vs

D1 D2

ClampDBD

Lm

Ls

CLS

HS

LS

L

Tr

CDC

Vs

D1 D2

ClampDBD

Lm

Ls

CLS

HS

LS

L

Tr

CDC

Vs

D1 D2

ClampDBD

Lm

Ls

CLS

Origin of Parasitic Parallel Resonance

remaining v-t product in transformer

charges on switch output capacitances

stored energy on CDC

level shifting: free swinging

parasitic parallel resonance between Lm and Clamp

HS

LS

L

Tr

CDC

Vs

D1 D2

ClampDBD

Lm

Ls

CLS

HS

LS

L

Tr

CDC

Vs

D1 D2

ClampDBD

Lm

LsCLS


Managing Parasitic Parallel Resonance

damping by adjusting

componentparameters timing

energy left in circuit circuit not clamped

free swinging of damped multi-resonant circuit

Trep


Damping by Parameter Variation

reduction of quality factor of parasitic parallel resonance

HS

LS

L

Tr

CDC

Vs

D1 D2

ClampDBD

Lm

Ls

CLS

HS

LS

L

Tr

CDC

Vs

D1 D2

ClampDBD

Lm

Ls

CLS

HS

LS

L

Tr

CDC

Vs

D1 D2

ClampDBD

Lm

Ls

CLS

lamp capacitance fixed by application

transformer optimized and fixed by v-t rating

transistors fixed by max currents

DC-blocking capacitor

low damping possible to cost of reduced ignition support

HS

LS

L

Tr

CDC

Vs

D1 D2

ClampDBD

Lm

Ls

CLS

HS

LS

L

Tr

CDC

Vs

D1 D2

ClampDBD

Lm

LsCLS


Alternatives

switching pattern

repetition period

parameter variation not an option


0 1 2 3 4 5 6 7

x 10-5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2x 10

-3

t [ s ]

tra

nsfo

rme

r se

co

nd

ary

v-t

pro

du

ct [V

s]

25µs

44µs

60µs

Adjusting Repetition Period

optimize preconditions for next pulse

pulse

pp

rep tf

nT ++++

⋅⋅⋅⋅

++++≈≈≈≈

2

21

therefore meet:

reduced v-t product swing

reduced amplitude of resonance

n = 1

excessive v-t products!

n = 0

pulse start in minimum of volt-second swing – initial VLS minimal


Variation of Switching Pattern

keeping LS on during pulse pause

result:

reduced resonance frequency

vCDC constant and adequate to compensate v-t product

benefits:

lower v-t products reduce losses & prevent saturation of transformer

parasitic parallel resonance tamed


Additional Benefit: ZVS for HS On-Transition

x 10

3x 10

-3

0 0.2 0.4 0.6 0.8 1

x 10-4

0

100

200

300

400

VL

S[V

]

utilization of EL to charge CHS

VLSgate

time [s]

►efficiency increase from 80 % to 82 %

►ZVS turn-on of HS

keeping LS on during pulse pause but opened prior to next pulse

short closing directly before pulse stores energy in L

►tamed resonance


Comparision of switching patterns

0 0.2 0.4 0.6 0.8 1

x 10-4

-2000

-1000

0

1000

2000

0 0.2 0.4 0.6 0.8 1

x 10-4

-1

0

1

2

3x 10

-3

time [ s ] time [ s ] time [ s ] time [ s ]

0 0.2 0.4 0.6 0.8 1

x 10-4

0

100

200

300

400

V V V VLL LL

SS SS [

V ]

[ V

] [

V ]

[ V

]

0 0.2 0.4 0.6 0.8 1

x 10-4

0

100

200

300

400

0 0.2 0.4 0.6 0.8 1

x 10-4

-2000

-1000

0

1000

2000

V V V Vll ll aa aa

mm mmpp pp [

V ]

[ V

] [

V ]

[ V

]

0 0.2 0.4 0.6 0.8 1

x 10-4

-2

-1

0

1

2x 10

-3

time [ s ] time [ s ] time [ s ] time [ s ]

vt-

pro

du

ct

[ V

s ]

vt-

pro

du

ct

[ V

s ]

vt-

pro

du

ct

[ V

s ]

vt-

pro

du

ct

[ V

s ]

transformer v-t product

low-switch voltage VLS

lamp voltage Vlamp

standard switching pattern enhanced switching pattern


To Conclude

serious problem of parasitic parallel resonance

10 20 30 40 50 60 70 80 90-2000

-1000

0

1000

2000

time [µs]

vla

mp

[V

]

10 20 30 40 50 60 70 80 90-20

-10

0

10

20

i la

mp

[A

]

advanced switching scheme tames negative effects and brings additional benefit

x 10

0 0.2 0.4 0.6 0.8 1

0

100

200

300

400

VL

S[V

]

time [s]

►increased reliability & efficiency + 2 %

0 1 2 3 4 5 6 7 8 9

x 10-5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2x 10

-3

t [ s ]

voltage-tim

e p

roduct[ V

s ]

25µs

44µs

51µs

60µs

81µsadaption of repetition period Trep shrinks resonant amplitude

resonant ECG drives DBD lamp


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Resonance behaviour of a pulsed electronic control gear