for a 1.5-MW Magnetron Application* Development of a 45...

KAPRA 2004, Cheorwon Cityhall, Gangwon (July 9-10) Electrical Engineering Group ([email protected])

S. D. Jang, Y. G. Son, J. S. OhPohang Accelerator Laboratory

Pohang University of Science and Technology(POSTECH)

H. G. Lee, Y. S. Bae, H. G. Lee, M. H. Cho, and W. Namkung

Pohang University of Science and Technology(POSTECH)

San 31, Hyoja-dong, Pohang,Kyungbuk 790-784, S. KOREA

Development of a 45-kV Pulse Transformerfor a 1.5-MW Magnetron Application*

* This work is partially supported by KBSI and KSTAR project by MOST.


Introduction

Microwave heating system of KSTAR consists of ECH and LHCD. ECH and LHCD offer the reliability of operation in the beginning of plasma formation and non-inductive current drive for long time steady state operation, respectively. LHCD demands C-band microwave system with a frequency of 5 GHz. A pulse generator with a power of 3.6 MW, 4 , 200pps is required to drive a high-power magnetron. The pulse transformer producing a pulse with a peak voltage of 45 kV is required to produce a 5-GHz microwave source in a 1.5-MW magnetron. We have designed the high power pulse transformer with 1:4 step-up turns ratio. The peak power handling capability is 3.6-MW (45 kV, 90 A at load side with 4 pulse width). In this paper, the results of the high power pulse transformer design and performance characteristics are presented.

* This work is partially supported by POSCON and KSTAR project by MOST.


Simplified Equivalent Circuit

Pulse Transformer

Lw

CDLPRE

RG

+

Load

VG

RL

LL

CL

Pulse Generator

SG

VG : Charging Voltage of Storage Capacitor

SG: Thyristor SwitchRG: Primary ImpedanceLW: Wiring Inductance

LL: Leakage Inductance

RE: Core Resistance

LP: Primary Inductance

CD: Distributed Capacitance

CLoad : Load CapacitanceRL : Load Impedance


Wave Shape Definitions

0000

Pulse length ττττp

TimeTr

Overshoot :CD, LL, γγγγ

Load Voltage

Backswing : CD, LE, RL, RE

Return backswing : CD, LL, Impedance mismatch

Tf

V0 0.9 V0

Fall time

0.1V0

Source Voltage

Rise time Tr : CD, LL

TTCLSrT )(2 σπ=

Droop : Lp, RL , ττττp

D = RL ττττw /(2 LP)Lp = 4ππππµeNP

2 Ae / Lm [nH]


Normalized Rising Pulse Waveform

0.94

0.96

0.98

1.00

1.02

1.04

1.06

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0S

y(t)

σσσσ=0.7σσσσ=0.8



0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 0.5 1 1.5 2S

y(t)

σ=0.5σ=0.5σ=0.5σ=0.5σ=0.6σ=0.6σ=0.6σ=0.6σ=0.7σ=0.7σ=0.7σ=0.7σ=0.8σ=0.8σ=0.8σ=0.8σ=0.9σ=0.9σ=0.9σ=0.9σ=1.0σ=1.0σ=1.0σ=1.0σ=1.1σ=1.1σ=1.1σ=1.1σ=1.2σ=1.2σ=1.2σ=1.2σ=1.3σ=1.3σ=1.3σ=1.3


Given parameters(Requirements)

Parameters Designed

peak load voltage(kV) 40 (negative)Peak load current(A) 96 (max)Load resistance(Ohms) 470 (Secondary) Primary RMS current(A) 26.93 (max)Secondary RMS current(A) 6.73 (max)Pulse width(µµµµs) 4Turns ratio 1:4 Pulse repetition rate 200 ppsLoad capacitance 31.4 pF

Design Parameters of the 1:4 Pulse Transformer

Designed parameters(Results)

Parameters Designed Measured

Turns ratio 4 3.87Primary turns 10 -Leakage inductance(µµµµH) 37 42.2Distributed capacitance(pF) 12.8 38.7primary inductance(mH) 21.6 19.85(LCR)Core material thick.(µµµµm) 50 -Magnetic flux swing(T) 0.68 -Effective permeability 800 803Gap length(µµµµm) 24 -Effective core cross-section(cm²) 66 -Mean magnetic path length(cm) 50.3 -Core weight(kg) 47 -


Design of Pulse Transformer(1:4) for 1.5 MW Magnetron

30

Primary winding : 10 turns with 2 parallel on each leg x Ф 1.6 x 4.15 Space (l c : 83)

83

65

100 200

221Ao= 75 Cm2 (25 x 3)Ae= 66 Cm2 (22 x 3)Lm = 50.3 Cm∆01= 8, ∆12= 10,∆23=10, corona gap=9Ns : 40 turnsCorona ring :all secondarywinding end point(dia. 5)

unit : mm

Secondary winding I: 40 turns x Ф1.8 x 2 Space (l c : 78), 78+15+7 =100

Secondary winding II: 10 turns x Ф 1.8 x 3. Space (l c : 27)

78

Designed by S.D. JangOctober 30, 2003


Coil Geometry and Winding Configuration

b

Isolated and bifilar winding(1:4)

30 83

65

100

221

78

Core(50x50.4)

Primarywinding

Secondarywinding

a = 181b = 66lC = 78∆12 = 10

a


Specification and Electrical Parametersof Pulse Transformer

Specification and Electrical Parametersof Pulse Transformer

1Pulse Droop[%/µµµµs]

0.4Rising Time [µµµµs]

1 : 4Step of Ratio

200Pulse Repetition Rate [Hz]

3.2Plat Top pulse width [µµµµs]

470Output Impedance []

45Secondary Voltage [kV]

96Secondary Current [A]

22.5Primary Voltage [kV]

375Primary Current [A]

1.2681.271Primary Inductance [mH]

19.8520.342Secondary Inductance [mH]

Measured ValueModel calculated ValueItem

38.744.2Distributed Capacitance [pF]

42.279.3Leakage Inductance [µµµµH]

Peak Voltage [kV] 45Peak Current [A] 96Load Impedance [Ω] 470HV Pulse Length [µs] 4Pulse Energy [J] 17.3Repetition Rate Max [Hz] 200Step-up Ratio 4PFN Charging Voltage [kV] 25PFN Impedance [Ω] 29.37PFN Section Cap [nF] 10PFN Section Inductance [µ H] 8.63PFN Section Number 7Charging Resistance [Ω] 100Thyratron ( CX1191D ) 8 MW, 35 kV, 500 A,

Design Parameters of ModulatorDesign Parameters of Modulator


7.5Winding length [cm]

50.3Mean Magnetic Path Length [cm]

10Primary Turn Number

1Distance between layers [cm]

800Effective magnetic Permeability

28.7Mean circumference between layers [cm]

0.68Total magnetic flux density swing [T]

0.88Core Packing factor [%]

66Magnetic Cross section Area[cm2]

40Secondary Turn Number

Parameters of Pulse TransformerParameters of Pulse Transformer

s

loadr L

RD2

τ=

s

s

BNVA∆

= τ

m

ses l

NAL2

0 ⋅= µµ

s

m

se

loadr N

lV

RBDµµ02⋅∆=

42 DL

rCL

T⋅

=π

c

sL l

NuL2

0 ⋅⋅∆= µ

nnuN

cT srr

12

−= επ

20 1

−∆

⋅=n

nluC crD

εε

VoltageSecondaryVWidthPulse

s ::τ


Dong-A 403

C-Band1.5MW MagnetronPulse Modulator

High VoltageSwitched ModePower Supply

Tyratron

Driver Circuit

Tyra tronHeater PowerSupply

MagnetronHeater

Power Supply

Magnetron Beam Voltage MonitorMagnetron Beam C urrent Monitor

EOLC

Protection Diode

ThyratronE2V

CX1191D

Tail Clipper

SurgeDespiker

Pulse Transformer

1:4

ResistorDivider

Dong-A 403Output Voltage 25 kVCharging Rate Peak 5 kJ/s Average 4.0 kJ/s

High VoltageCoaxialCable

MagnetronPulse Transformer

Tank

Frequency 5100 MHzOutput Power 1.5 MWRepetiton Rate 200 ppsEffic ieccy 52 %Beam Voltage 39 kVBeam Current 83 ARF Pulse Width 4.0 µµµµs

Peak Power 3.6 MWCharging Voltage 22.5 kVPFN Output Voltage 11.25 kVPFN Output Current 382 AHV Pulse Width (70% Voltage) 4.0 µµµµsRepetition Rate 200 pps

Pulse Modulator 7 Stage PFN

PFN impedance 29.37 ΩΩΩΩTotal Capacitance 68.26 nFTotal Inductance 51.6 µµµµHSingle Capacitance 10 nF

50 ΩΩΩΩ

30 ΩΩΩΩ

50 ΩΩΩΩ

G2G1

10 µµµµH

6.3 V12. 5 A

CPI SFD369

1 nF

25 ΩΩΩΩ

P1

P2

M2

M1M3

M4

E1

E2

E3

E2-1 E4 E4-1CT-2

Electron GUNHeater

Power Supply

ElectronGU N

ResistorDivider

Gun Beam Voltage Monitor

Gun Beam Current Monitor

50 ΩΩΩΩ

CT-1

BNC-1 BNC-2 BNC-3 BNC-4

Heater voltage : 6.3 +/_ 0.5 V(Max:6.8 V), 12.5 A

Heater voltage : 5 V +/_ 1 V(Max: 6 V), 28 A

Heater voltage : 9 V+/_ 1 V(Max: 10 V), 10 A

FilterPCB

2 MΩΩΩΩ

Dump SW

8.6 µµµµH

10 nF

DS2124

DS2124

RF-Output

CathodeVane

Anode

Strap

HV Probe

Circuit Diagram of ModulatorCircuit Diagram of Modulator

Charging Circuit Discharging circuit


1100800

PressureGauge/ Valve

5.0-GHz magnetron

Optical cable

Drydummyload

Dry Dummy Load

Dual directionalcoupler E-bend

or H-bendThyratronSwitch / PFN

InverterPowersupply

PulseTransformer

Control Unit(PLC /w pulse gen.)

37 kV

, 70

APFN Pulse Modulator(Max 45 kV, 96 A, 4 µµµµs)

19” rack

Trigger pulse (Internal & External DG535)Interlock signals (Contact Closures)RS232 comm port (for remote control)

Interlock signals-Reflection power > 50 %-Arc signal (in waveguide)-SF6 gas pressure < 30 psig-Magnetron cooling fan off

Heater DC 5 V28 A

FAN

Air cooled magnetron• SFD369• Frequency : 4.9 – 5.1GHz• Peak power output: 1.5MW• Duty Cycle: 0.001 (1 kHz

repetition)• Peak Anode Voltage Max:

40.5 kVPeak Anode Current Max: 90 Amps

• Pulse Width: 0.4~1.4 µµµµs

SF6

WR187 w/g components

• Straight waveguide• E-bend• H-bend• Dual directional

coupler• 4-port circulator

Arc detector

4-portcirculator

Layout of The Test System


Pulsed Magnetron Pulsed Magnetron

CPI SFD-369

5, 28Heater V, I (V, A)

52Efficiency (%)

0.0008Duty1.68Peak Output Power (MW)

4Pulse Width (µµµµs)470Magnetron Impedance ( Ω )83Anode Current (A)

39Anode Voltage ( kV )

Average Output Power (kW)

Frequency (MHz ) 4900-5100


Modulator Test SetupModulator Test Setup

472

Pulse TR

472

Pulse TR

Photographs for LHCD Test System

PFN & HV BoxPFN & HV Box

Pulse TRPulse TR


Test and Simulation ResultsTest and Simulation Results

Ti me

5. 008ms 5. 010ms 5. 012ms 5. 014ms 5. 016ms 5. 018ms- I ( R3)

- 100A

- 50A

- 0A

- 140ASEL>>

V( R3: 2)

- 60KV

- 40KV

- 20KV

0V

Pulse Length : 4 s

Rise Time : 0.5 s

Fall Time : 1.2 s

Flatness :1.8 %

Flattop Pulse width : 2.8 us45 kV

97 A

45 kV

97 A

Rise time 0.4 us

Flatness 1.8 %

Flattop Pulse width 2.8 us


Summary & Future Plan

• Summary

1. Equivalent circuit analysis of the pulse transformer.

2. Normalized rising waveform as function of the damping factor.

3. Design of the 1:4 pulse transformer for a microwave tube.

4. Establishment of the general design procedure, equation

for high-power pulse transformer.

5. Waveform analysis for simulation circuit of the pulse system.

6. Measurement of equivalent circuit parameters for transformer

• Future plan

1. Measurement of pulse characteristics according to specification.

2. HV performance test by using a 5 GHz, 1.6 MW magnetron load for a LHCD system.

3. Optimum design and fabrication for high efficiency.

for a 1.5-MW Magnetron Application* Development of a 45...

Documents

Transcript of for a 1.5-MW Magnetron Application* Development of a 45...