Design & Development of 40kV/5kA Pseudospark Plasma Switch & Pasotron

(PSC-0101)

Presented By-VARUN PATHANIA

(Project Fellow)

Project LeaderDr. U.N. Pal

Switching characterization of double gap, 40kV/5kA demountable PSS.

Fabrication and assembling of sealed-off double gap PSS.Initial switching characterization of sealed-off PSS.Reservoir characterizationElectrical characterization of ferroelectric trigger source Switching characterization of sealed-off 25kV/5kA PSS.Switching characterization of radial channel 20kV/20kA PSS. Electrostatic analysis of PSS using Omni Trak.Electrostatic and plasma simulation of PSS using COMSOL.

Work Assigned

Switching characterization of double gap, 40kV/5kA demountable PSS

Modular double gap PSS

Schematic circuit

Experimental Set up

Probes

400 nF

5.25

Cathode

Anode

Trigger

Self breakdown voltage measurement at different H2 pressure

Trigger pulse from the pulse generatorRise time: 50 ns, Pulse width: 400 ns

Operating pressure range: 30 – 50 Pa Hold–off voltage for Gap1, Gap 2: > 30 kV Calculated hold–off voltage for Gap1+Gap2: > 60 kV Measured hold–off voltage for Gap1+Gap2: 40 kV (Max)

Switching characterization of double gap, 40kV/5kA demountable PSS

Experimental Results: Breakdown Voltage (BV): 39.5 kV Output Currents: 6, 10 kA Rise time ~ 250ns BV Fall time ~ 228ns Pulse width ~ 2.52µs Delay time > 200 ns

Switching characterization of double gap, 40kV/5kA demountable PSS

Anode and Cathode Sub-assemblies

Intermediate Anode and Cathode Sub-assemblies

Sealed-off double gap 40kV/5kA PSS

183.2 mm

Ø96 mm

Test setup for conditioning of 40kV/5kA PSS

Results Obtained:-Hold off Voltage = 52kV

Parameters:-Gas Used = HydrogenGas Pressure = 30-40 Pa

Experimental Results: Breakdown Voltage(BV): 35.4 kV Output Currents: 7kA Rise time ~ 350ns BV Fall time ~ 50ns Pulse width ~ 1.52µs Delay time > 300 ns

-2 -1 0 1 2 3 4 5 6

0

10

20

30

Volta

ge(k

V)

Time(s)

0

1

2

3

4

5

6

7

8

Cur

rent

(kA)

Switching characterization of double gap, 40kV/5kA sealed-off PSS

Activation, gas loading and characterization of Hydrogen Reservoirs

Reservoir Used:Reservoir used: Non-evaporable Sintered Porous GetterMaterial: Zirconium power and St 707 power (70%Zr +24.6% Vanadium + iron)Reservoir Type: St 172/LHI/9.5-7.5Activation current: 8.3A @ 900oCResistance of Single Reservoir: 259 mΩResistance of two reservoirs in parallel: 129 mΩ

4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.50

20406080

100120140160180200

Pres

sure

(Pa)

Current (A)

Forward Reverse

R

C

Characterization of Ferroelectric Trigger Source

Experimental Results: Trigger voltage nearly same Trigger current decreases with pressure Collector current increases with pressure

0 20 40 60 80 1000.00.51.01.52.02.53.03.54.04.55.0

Trig

ger V

olta

ge(k

V)

Pressure(Pa)

R=50 ohm & D=10mm with diffrent Presure

0246810121416182022

Colle

ctor

Cur

rent

(A)

32

34

36

38

40

Trig

ger C

urre

nt(A

)

0 20 40 60 80 1000

1

2

3

4

Trig

ger V

olta

ge(k

V)

Pressure(Pa)

R=10 ohm & D=10mm with diff pressure range

4

8

12

16

20

24

Col

lect

or C

urre

nt

28

32

36

40

44

Trig

ger C

urre

nt

Characterization of Ferroelectric Trigger Source

0 2 4 6 8

0

5

10

15

20

25

Brea

kdow

n vo

ltage

(kV)

Time (s)

LPT - 05 H2 gas

Reservoir current 5.8 A

0

2

4

6

Disc

harg

e cu

rren

t (kA

)

Parameters used: Load resistance=3.25 Charging capacitance=205nF

Results obtained: Breakdown Voltage: 24.5kV Output Current: 5.2 kA Fall time ~ 150 ns Rise time ~ 300 ns

Schematic Circuit of 25kV/5kA PSS Experimental set up

LPT -05

Switching characterization of 25kV/5kA sealed-off PSS

Experimental set up Schematic Circuit diagram

High current PSS

Schematic view Demountable type PSS

Switching characterization of 20kV/20kA PSS

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

0

5

10

15

Volta

ge(k

V)

Time(s)

Capacitance: 800 nFload resistance: 1

0

5

10

Cur

rent

(kA)

Results obtained : Breakdown Voltage: 15kV Output Current: 13 kA Fall time ~ 100ns Rise time~122ns

0 10 20 30

0

5

10

15

20

Brea

kdow

n vo

ltage

(kV)

Time (s)

Capacitance: 800 nFShort circuit/no load

-20

-10

0

10

20Di

scha

rge

curr

ent (

kA) Results obtained :

Breakdown Voltage: 18.8kV Output Current: 20 kA Fall time ~ 130ns

Switching characterization of 20kV/20kA PSS

Steps in OMNI TRAK SimulationMesh generation

Organizing AMaze simulations by HiPhi.

PHIVIEW generates plots and analyses of solutions from HiPhi.

Electrostatic analysis using OMNI TRAK Soft.

Electrostatic Analysis of Single Gap PSS

Upto 200V

Between 20-40kV

Electrostatic Analysis of Double Gap PSS

Geometry Design.Assign design parameters to geometry.Assign boundaries for electrodes.Assigning parameters for dc discharge.Result analysis.

Steps for COMSOL

Plasma parameter analysis using COMSOL Soft.

Plasma parameter analysis using COMSOL Soft.

Plasma parameter analysis using COMSOL Soft.

PublicationsJournals:

1. H. Rahaman, V. Pathania, D. K. Pal, R. P. Lamba, B. L. Meena, N. Kumar, U. N. Pal, Ram Prakash, “Plasma based Double Gap Pseudospark Switch for Pulsed Power Modulators” Int. J. Electronics and Comm. Tech., vol. 6, issue 1, pp. 134-36, 2015.

2. V. Pathania, D. K. Pal, B. L. Meena, N. Kumar, U. N. Pal, R. Prakash and H. Rahaman, “Switching Behavior of a Double Gap Pseudospark Discharge” in IEEE Trans. Electrical Devices Sci., July. 2015.

3. R.P.Lamba, V. Pathania, B. L. Meena, H. Rahaman, U. N. Pal and Ram Prakash “Investigation of a High urrent Linear Aperture Radial Multichannel Pseudospark Switch” in Rev. Sci. Instrum. Vol. 86, 103508, 2015.

Conferences:

1. V. Pathania, H. Rahaman, B. L. Meena, D. K. Pal, N. Kumar, U. N. Pal and Ram Prakash, "Development of a Plasma based Multi-Gap Pseudo-Spark Switch for 40 KV/10 kA Ratings" 29th National Symposium on Plasma Science and Technology (PLASMA- 2014), 8-11, Dec. 2014, Kottayam, Kerala.

2. V. Pathania, H. Rahaman, D. K. Pal, R. P. Lamba, B. L. Meena, N. Kumar, U. N. Pal and Ram Prakash, “Switching Characterization of Double-Gap 40kV/5kA Pseudospark Switch” National Workshop on Vacuum Electronic Devices and Applications (VEDA- 2014), 20-21 March 2015, School of Physics, Devi Ahilya Vishwavidyalaya, Indore (M.P.).