ac-dc converters or rectifiers

AC-DC Converters or Rectifiers

Fixed voltage1 or 3- phase ac

Diode rectifierFixed voltage dc

Fixed voltage 1 or 3-phase ac

Fully controlled thyristor rectifier

Variable voltage dc

Fixed voltage1 or 3- phase ac

Half-controlledthyristor rectifier

Variable voltage dc

Fixed voltage 1 or 3- phase ac

Transformer with taps

Diode rectifier

Variable

Voltage dc

Variable Voltage ac

Fixed voltage1 or 3- phase ac

Rectifier with Self Commutated

devices

Variable

Voltage dcFixed voltage1 or 3- phase ac

Diode rectifier

chopperVariable Voltage dc

Fixed voltage dc

Variable voltage dc

Ac motor

Fixed voltage ac

Dc generator

f

Diode rectifier

Variable voltage dc

Ac motor

Fixed voltage

1 or 3-phase ac

Magnetic amplifier

Diode rectifier

variable

Voltage dc

Fixed voltage

3-phase acAmplidyne

variable

Voltage dc

Ac voltage controllers

Fixed voltage

3-phase ac

Autotransformer Of fixed turns

ratio

Lower (fixed)

Ac voltage

Fixed voltage

3-phase ac

Transformer with taps

variable

Voltage ac

Fixed voltage

3-phase acMagnetic amplifier

variable

Voltage ac

Fixed voltage

3-phase ac

Thyristor voltage controllers

variable

Voltage ac

Fixed voltage dc

Semiconductor chopper

variable

Voltage dc

DC supply

chopperSix step inverter

IML

CVd

Filterl d

Dc link

chopperAC supply

Six step inverter

IML

CVd

Filter

Dc link

l d

PWM inverter IML

CVd

Filter

Dc link

l d

DC supply

Diode bridgeAC supply PWM inverter IM

LC

Vd

Filter

Dc link

l d

Ld

Fully controlled

rectifierCSIVd

Dc link Induction

motor

chopper CSIVd

Dc link Induction

motor

DC supply

ACsupply

Vds

3-phase

Ac supply

ldL d

Vdl

T1T

3 T5

T2T6T4

Source side converter Load side converter

Synchronous motor

o

wm

TF

wm

o

Ts

Ts

Tv Tc

TvTc

Tor que

o

+ w

+T

T L

-T

-w

olT

oTl

wmwm

p

t

p

t

p

p

tt

Reverse motion

Forward motion

P

t

P

Motor

IL

v

w

Dry

Friction

Viscous

Fan

Friction

wL

vm

L T

P= f (t)N= f (t)

P= f (N)

N

P

P 2

1

t1 t

2 P, t

Loaded cage

TL I

IV

TL

Counterweight

Loaded cage

ForwardMotoring

CounterweightCounterweight

Emptycage

IIIReverse

Motoring

Load torque with loaded cage

Load torque with empty cage

Counterweight

Emptycage

II

TT1

Fig. 2.10. Motor- load system

Motor Load

TL

TM

W

V

M

Fig. 2.12 Motor-hoist load system

-T -T

TL

TL

Stiction

+i

TL

Fig. 2.2. Speed torque curve of dry friction load Fig. 2.3. Speed torque curves of Viscous friction load.

++

- -

-T +T -T +T

Fig. 2.4. Speed torque curve of a fan type load. Fig. 2.5. Speed torque curve of a constant power load

2

1

hFig.2.6. Forces during the upgradient motion of a train, Fig.2.7. Hoisting .mechanism

F W

Jn, n

M N

i1

i2

in

J1,

1

J2,

2

TL

Fig.2.11. Motor-Load system with gears.

TL

Te

ONE PERIOD

Fig.2. 8. Speed-torque characteristic of a reciprocating compressor.