Power Service GmbH Satic frequency convertersPage 1 19.07.2002

Static Frequency Converters

Rolf Kramer SER/EIG

Power Service GmbH Satic frequency convertersPage 2 19.07.2002

Basics Static Frequency Converter

BASIC

Principle of operation

Static Frequency Converter

(SFC / LCI.ST)

Date: 19.07.2002

Power Service GmbH Satic frequency convertersPage 3 19.07.2002

AC

AC

SMGT

ie

Tr

1. LCI DRIVE SYSTEMS Today

Frequency starting with Static Frequency Converter (SFC)

Other terms are:

LCI = Load Commutated Inverter

SSD = Static Starting Device

U

Power Service GmbH Satic frequency convertersPage 4 19.07.2002

1. LCI DRIVE SYSTEMS Basic circuit

Control and protection system

Starting excitation system

Rectifier SRN Inverter SRM

DC link reactor

Power supply side

Static frequency converterStatic starting system

id

ie

SM

Isolating transformer

Power Service GmbH Satic frequency convertersPage 5 19.07.2002

1. LCI STARTING SYSTEMS

6/6-pulse

12/12-pulse

6/6-pulse withstep-up trafo

Power Service GmbH Satic frequency convertersPage 6 19.07.2002

1. LCI DRIVE/STARTING SYSTEMS

Standard converter configurations and options.

Converter for Drives( DR )

Soft Starter( SO )

Gas Turbine Starter ( ST )

Configuration6/6-pulse

12/12-pulse2x6/6-pulse

6/6-pulse12/12-pulse 6/6-pulse

ThyristorCooling

Block integra-ted Excitation

AC-Controlleror

6-pulse Rectifier

6-pulse Rectifieror none 6-pulse Rectifier

AirWater

AirWater Air

Power Service GmbH Satic frequency convertersPage 7 19.07.2002

6. Run up to synchronous speed

L1

L2

L3

e

L1

L3

i

Id

e Magnetic flux produced by rotor windingsi Magnetic flux produced by stator windings

Power Service GmbH Satic frequency convertersPage 8 19.07.2002

L1

L2

L3

6. Run up to synchronous speed

L1

L3

ieeeeeeeeee

60°Id

e Magnetic flux produced by rotor windingsi Magnetic flux produced by stator windings

Power Service GmbH Satic frequency convertersPage 9 19.07.2002

L1

L2

L3

6. Run up to synchronous speed

Id = 0

e

Power Service GmbH Satic frequency convertersPage 10 19.07.2002

L1

L2

L3

6. Run up to synchronous speed

L2

L3

i

e eee

ee

60°

Id

e Magnetic flux produced by rotor windingsi Magnetic flux produced by stator windings

Power Service GmbH Satic frequency convertersPage 11 19.07.2002

L1

L2

L3

6. Run up to synchronous speed

Id = 0

e

Power Service GmbH Satic frequency convertersPage 12 19.07.2002

L1

L2

L3

e

6. Run up to synchronous speed

L2

L1

i

Id

e e ee60°

Repeat startup

e Magnetic flux produced by rotor windingsi Magnetic flux produced by stator windings

Power Service GmbH Satic frequency convertersPage 13 19.07.2002

6. Run up to synchronous speed

0 naSpeed

SM

idMachine

converter

SM

idMachine

converter

Fluxcalculation

t

160° (i.e. 20°)MC

t

id

uuiut

tid

=180° (i.e. = 0°)MC

uu iu

Pulse mode operation Machine commutated operation

Control from flux calculation Control from machine voltages

Power Service GmbH Satic frequency convertersPage 14 19.07.2002

6. SFC start to turn mode (70 rpm) pulse mode

DC Link current -Idx: UAC 326-A19 -5V= 1280 VDC

Excitation current Iex: UAC 326-AIC 5V= 350 ADC

Speed nx: UAC 326-AO7 10V= 3000rpm

Machine voltage Urt comp: SA9923-X12 7V= 1800 VAC

Power Service GmbH Satic frequency convertersPage 15 19.07.2002

6. Machine Voltage at 1165 rpm machine commutation

Machine Voltage: URT: SA9923-X4 7V=1800 VAC

Machine volatage: URtcomp: SA9923-X127V=1800 VAC

Power Service GmbH Satic frequency convertersPage 16 19.07.2002

Machine commutated mode

Pulsing mode

Machine Torque produced by SSD

Line Voltage, Line Frequency

Machine Current, DC-Current

Machine Voltage, Machine Power

Breaking Torque produced byCompressor

Ignition of theGas Turbine

Excitation Current

Field-weakening mode

nRated Speed

8. Start sequence

Self sustaining speed