April 25, 2011 Electric Railway Traction

7. Other types of propulsion systems

Current Source inverter

R

S

T

T1

T2

T3

T4

T5

T6

D1

D2

D3

D4

D5

D6

Id

a)

R

S

T

T1

T2T6

D1

D2D6

–C

Id

+

Id

b)

R

S

T

T1

T2T6

D1

D2D6

C

Id

–

+

Id

c)

R

S

T

T1

T2T6

D1

D2D6

C

Id

Id

u c

-u c

u ci

t r = turn-off time

t 1 t 2

i

t c = total commutation time

t

t

diode commutation

i T

i S i T

i S

-I d

April 25, 2011 Electric Railway Traction

7. Other types of propulsion systems

Motor voltage when power is supplied from a current source inverter

uST

t

terminal voltage u ST ( )

voltage, lower capacitor group u CST ( )

April 25, 2011 Electric Railway Traction

7. Other types of propulsion systems

Machine quantities at steady-state

torque T

phase voltages

phase curents

t

t

e R e S e T

i T i R i S

s

I d

-I d

April 25, 2011 Electric Railway Traction

7. Other types of propulsion systems

DC voltage fed system with input converter and current source inverter

Motor

Generator

R

S

T

April 25, 2011 Electric Railway Traction

7. Other types of propulsion systems

Synchronous motor drive with current source inverter

eR,S,T

T1

T2

T3

T4

T5

T6

uR

S

T

dI dL

April 25, 2011 Electric Railway Traction

7. Other types of propulsion systems

The mmf wave’s six directions

T1-T6

T5-T4

T3-T4

T3-T2

T1-T2

Fr

T5-T6

s

sF

April 25, 2011 Electric Railway Traction

7. Other types of propulsion systems

Voltages and torques under ideal conditions

T1

T2

T3

T4

T5

T6

induced stator voltages

e R e S e T

excitation sequence, upper thyristor group

excitation sequence, lower thyristor group

t 1 t 2 t 3 t 4 t 5 t 6

T= u d I d s

u d

s t

April 25, 2011 Electric Railway Traction

7. Other types of propulsion systems

Commutation from thyristor T1 to thyristor T3

R

S

T

T1

T2

T3 R,S,Te

RSe

Id

RiSi

Id

e R e S e T

s t

t

commut at ing

volt age

e R S = e R - e S

e R S at no-load

i R

i S

i S

i R

= current delay angle

u = overlap angle

t hyrist or’s reverse recovery t ime

( tq)

respect angle

t T 3

t

t u

t 3

s t

Induced phase voltages

Possible commutation interval

current

e,TT

s

u

t

t

Id

-Id

iR

iT

iS

eR

eT

eS

i

DC link pulsation and forced commutation

1'

2'

3'

4'

1

2

3

4

5

6

1

2

3

4

5

6

Thyr com1

Thyr com2

+ - T1

T4

T1'

T4'

Id

April 25, 2011 Electric Railway Traction

7. Other types of propulsion systems

Example synchronous motor drive (France)

April 25, 2011 Electric Railway Traction

7. Other types of propulsion systems

Synchronous motor drive at 1.5 kV DC

April 25, 2011 Electric Railway Traction

7. Other types of propulsion systems

Synchronous motor drive at 25 kV, 50 Hz AC