Siemens-Basics_AC_Drives Working principle's

Siemens-Basics_AC_Drives

1. SITRAIN Training Documents - © Siemens AG 2012. All rights reserved.
Basics Of Electrical
Drives

2. Siemens AG © 2012 Page 1 - 2
SITRAIN
Course DR-BD
Application Examples
Printing machinesPumps
Converter technology
Rolling machine drives
Individual drives
“Superior“
single drives
Large drives
Cable carsElevators Compressors
“Superior“
single drives
Paper machines

3. Siemens AG © 2012 Page 1 - 3
SITRAIN
Course DR-BD
Overview
Electrical
machine
Gearbox
controller
converter
Voltage
Current
Frequency
Supply
DC or AC
Asynch. or Synch.
Motor Gen.
Load
Active, passive
characteristic
curve

4. Siemens AG © 2012 Page 1 - 4
SITRAIN
Course DR-BD
Electric motors and generators work by converting electrical energy into mechanical energy (motor)
and mechanical energy into electrical energy (= generator).
This process can be reversed such that almost any motor can also function as a generator.
This reversal principle applies to DC, induction and synchronous motors.
Reversing the flow of energy may need to be restricted or even special equipment installed to protect
frequency converters should they be used.
Example:
Electrical
energy
Mechanical
energy
Motor operation
Basic principles
of electromagnetic energy transfer

5. Siemens AG © 2012 Page 1 - 5
SITRAIN
Course DR-BD
DC Motor types

6. Siemens AG © 2012 Page 1 - 6
SITRAIN
Course DR-BD
Rectifier
Converter
Inverter
I
1
U
1
f
1
I
4
U
4
f
4
I
2
U
2
I
3
U
3
DC
chopper
controller
Converter types
DC converters

7. Siemens AG © 2012 Page 1 - 7
SITRAIN
Course DR-BD
U
N(t) U
d
(t)
Uncontrolled B2 circuit
Bridge circuits
L1
L2
D4
D3
D2
D1
RU
d
I
d
U
N
L1
L2
D4
D3
D2
D1
R
I
d
L1
L2
D4
D3
D2
D1
R
Id

8. Siemens AG © 2012 Page 1 - 8
SITRAIN
Course DR-BD
One series for all performance ranges
Rated connection voltage 50/60 Hz
- Arma-
ture
400V / 480V
3AC
400V / 480V / 575V
3 AC
400V / 480V/
575V / 690V
3AC
400V / 480V/
575V / 690V / 830V
3 AC
400V / 480V / 575V /
690V / 830V / 950V
3 AC
Rated current
- Arma-
ture
15A,
30A
60A - 125A,
210A - 280A
400A - 600A 720A - 850A 950A - 1200A 1600 - 3000A
- Field3A (325V/375V=)
5A (325V/375V=)
10A (325V/375V=)
15A (325V/375V=)
25A (325V/375V=)30A (325V/375V=) 40A (375V=) 40A (375V=)
15-30A 60-280A 400-600A 720-850A 1500-3000A950-1200A

9. Siemens AG © 2012 Page 1 - 9
SITRAIN
Course DR-BD
DC MOTOR /DRIVE ???????? AC MOTOR/DRIVE !!!!!!!!!!!
 
 


1 Simple control circuit 1. Complex Control-ciruits
2 Motor-Drive capital cost cheap 2. Motor drive Capital cost more
3.DC Motor has a FLAT and Steady Characteristics 3. AC Motor has non steady Characteristics
AC Squirrel Cage induction motor
5.Commutator Cleaning ,Carbon Brush Changing ,Brush alignment
Etc Was a Maintenance Problems
4.AC motor has no extra or external components
hence Squirrel Cage motor was maintenance free.
6. Motor-Drive Running cost HIGH 5. Motor drive running cost low
7 - DC . High accuracies ,Fine resolutions & Excellent dynamic
response for
-cold rolling mills
-few extruders (low speed high torques)
Paper calendar lines (Exceptional )
Polyester Film lines (Exceptional)
7 – Changeover from DC to AC.
Spinning Machines ,Pre-heater fan ,Packaging,
Cement, Kilns, Spindles, Press, Printing
6.AC . medium Accuracies ,Normal Resolutions , Average
Dynamic Response
- Fans ,Blowers(Energy Saving)
- Centrifugal/Reciprocating Pumps
- Belt Conveyors
- Compressor
- Agitator ,mixers,Centrifuges
- Crane Hoist ,Trolleys, Extruders
-,Hot rolling mills, Wire drawing
Comparison Between DC Drive and AC Drive System

10. Siemens AG © 2012 Page 1 - 10
SITRAIN
Course DR-BD
AC Motor Types
AC Motor
Asynchronous
Motor
Synchronous
Motor
Servo Motor
Squirrel Cage
IM
Slip Ring
IM
Synchronous
Servo
Asynchronous
Servo
With Brush With Out Brush

11. Siemens AG © 2012 Page 1 - 11
SITRAIN
Course DR-BD
Fan
Terminal box
Terminal board
Bearing shield
Fan cover
Shaft
Rotor
Stator windings
Drive end Non-drive end
Asynchronous motor
Design

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SITRAIN
Course DR-BD
Stator, when fed with three-phase current,
generates a rotating field
Rotor with cage winding
Design
Stator and rotor

13. Siemens AG © 2012 Page 1 - 13
SITRAIN
Course DR-BD
The three-phase currents in the stator winding generate
a rotating field - the stator field.
The rotating field induces voltages in the rotor bars,
which can develop currents by way of the cage winding.
The currents in the cage winding then produce a
magnetic rotating field - the rotor field.
The induction effect in the rotor becomes greater the larger
the difference in speed between the rotating field
and rotor speed.
When the rotor turns at the frequency of the rotating field, no voltage is
induced in the rotor. This called synchronismen or synchronous speed
The position of both fields (stator and rotor field)
in relation to each other and the magnitude of the fields
determines the torque achieved.
Principle
Rotor

14. Siemens AG © 2012 Page 1 - 14
SITRAIN
Course DR-BD
Rotor leakage
inductance
L‘
SR
Stator leakage
inductance
L
SS
Magnetizing
inductance
Rotor
resistance
R‘
R/s
Stator Rotor
R
S
R
R
L
R
L
S
Stator
resistance
R
S
L
h
Equivalent circuit diagram

15. Siemens AG © 2012 Page 1 - 15
SITRAIN
Course DR-BD
Why we require Variable Voltage?
Ns = 120 F / P
Torque is proportional to Flux and Armature current .
T α Φ x I
The e.m.f induced in rotor is
E = 4.44 x F x Φ x Z
F – Supply Frequency
Φ – Flux Density
Z – NO of Conductors
Φ V Fα
Thus if we reduce only frequency ,then flux
will also reduce.Therefore we need to
reduce voltage proportional to reduction in
frequency.

16. Siemens AG © 2012 Page 1 - 16
SITRAIN
Course DR-BD
Torque-Speed Characteristics Of Induction Motor

17. Siemens AG © 2012 Page 1 - 17
SITRAIN
Course DR-BD
Voltage
Frequency
Current
Speed
Power factor
Power
Asynchronous motor
Rating plate

18. Siemens AG © 2012 Page 1 - 18
SITRAIN
Course DR-BD
Requirement of Modern Machine
Conventional Technology
Requirement of Modern Machines
Control over Torque & Speed of the motor ?
Control over Torque & Speed of the motor ?
NO !
YES !
Electric
Supply
Starter Motor Gear Box Load
Electric
Supply
Power Converter Motor Load
DRIVE

19. Siemens AG © 2012 Page 1 - 19
SITRAIN
Course DR-BD
Few Expectation of Drive
 Variable speed at the motor shaft maintaining torque producing capability of the motor
 Speed regulation
 Controlled acceleration & deceleration
 Quick & safe reversal and braking
 Protection against abnormal conditions
 Auto-optimization
 Easy fault diagnostics
Communication capable
Energy Saving

20. Siemens AG © 2012 Page 1 - 20
SITRAIN
Course DR-BD
Power Block Diagram
Rectifier Inverter
+
-
3 Φ Constant Voltage
Constant Frequency
3 Φ Variable Voltage
Variable Frequency

21. Siemens AG © 2012 Page 1 - 21
SITRAIN
Course DR-BD
Rectifier Section
Uncontrolled Bridge Rectifier
Output DC Voltage
Input AC Voltage

22. Siemens AG © 2012 Page 1 - 22
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Course DR-BD
Without precharging:
- Rectifier diodes, fuses, DC-link
capacitors destroyed
- Supply system loaded
Precharging - Circuit versions:
5.
1.
4.
2. 3.
DC link
DC link pre-charging

23. Siemens AG © 2012 Page 1 - 23
SITRAIN
Course DR-BD
M
Motor
Direct on DC link:
> For receiving regenerative energy
> For bridging temporary supply interruptions
> Loading the precharging input circuit of the infeed too
M
Motor
With separate precharging input circuit:
> For bridging longer supply interruptions
> Larger capacitances possible
DC link
DC link capacitor modules

24. Siemens AG © 2012 Page 1 - 24
SITRAIN
Course DR-BD
M
Motor
Balancing and
discharge resistors
Typical circuit design:
Electrolytic capacitors
each with U
n
= 350 V
where U
Z
= 600 V
U
DC
t
approx. 5 min
Caution when working on the DC link!
Always check the voltage with a
measuring instrument!
Never cause a short-circuit.
(e.g. with a non-insulated tool)!
60 V
DC link
DC link discharging

25. Siemens AG © 2012 Page 1 - 25
SITRAIN
Course DR-BD
Frequency converter for 4-quadrant operation
4-quadrant operation
Speed/
voltage
Clockwise
rotation
Braking
Clockwise
rotation
Driving
Torque/current
Counterclockwise
rotation
Driving
Counterclockwise
rotation
Braking
Single quadrant
M
M
Energy flow
in single-quadrant operation:
Energy flow
in four-quadrant operation:

26. Siemens AG © 2012 Page 1 - 26
SITRAIN
Course DR-BD
Frequency converter for 4-quadrant operation
Basic circuit
Line-side
inverter
Motor-side
inverter
Supply:
400V
50Hz
U
V
W
iINV
INiN1
iC
L1
L2
L3
Line-side
filter
DC link
capacitors
Motor-side
filter
(optional)

27. Siemens AG © 2012 Page 1 - 27
SITRAIN
Course DR-BD
Power Switching Devices
TRANSITOR MOSFET IGBT
Driving Ckt Complex Simple Simple
Switching Frequency Medium High High
Conduction Losses Low Medium Low

28. Siemens AG © 2012 Page 1 - 28
SITRAIN
Course DR-BD
PWM Technique

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Course DR-BD
Power Converter Output

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Course DR-BD
 Effects of voltage and current
harmonics
t
Mains-fed operation:
-Sinusoidal voltages and currents
-Frequency and voltage amplitude
are constant
Converter-fed operation:
-Frequency and voltage
can be set as required,
-but harmonics occur
Pulse width modulation at the frequency converter

31. Siemens AG © 2012 Page 1 - 31
SITRAIN
Course DR-BD
Single drive
M
Motor
DC link (DC busbar):
capacitors with rectified supply
voltage
approximately 1.35 to 400 V = 540 V
Variable frequency
and voltage
U
t
U
t
U
t
Three-phase supply, e.g.
3 AC, 400V, 50 Hz
InverterRectifier Capacitor
Closed-loop control
U
t

32. Siemens AG © 2012 Page 1 - 32
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Course DR-BD
Specifications of Inverter Duty Motor

33. Siemens AG © 2012 Page 1 - 33
SITRAIN
Course DR-BD
Ready-to-use
cabinet units for
high power ranges
(Cabinet)
Flexible
built-in units for
high power ranges (Chassis)
Modular
booksize units for
small and medium
power ranges
Compact
blocksize units for
small and medium
power ranges
Compact
booksize units for
small and medium
power ranges
SINAMICS overview
Various formats

34. Siemens AG © 2012 Page 1 - 34
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Course DR-BD
Overview SINAMICS
price

35. Siemens AG © 2012 Page 1 - 35
SITRAIN
Course DR-BD
The drives family SINAMICS
low voltage V and G
Low voltage
Basic
performance
General Performance
V20
G120C/G120/
G120P/G120P
Cabinet
G110D/G120D/
G110M
G130/G150 G180
012 .. 30 kW 0,37 … 630 kW 0,37 … 7,5 kW75 … 2700 kW 2,2 … 6600 kW
Pumps, fans,
conveyor belts,
compressors,
mixers, mills ,
Textile machines
Pumps, fans,
compressors,
conveyortechnology,
mixers, mills and
extruders
G120:single axis
positioining
applications
G120D
conveyor
technology:
single-axis
positioning
applications
Pumps, fans,
conveyor belts,
compressors,
mixers, mills
and extruders
Industry specific
for
pumps, fans,
compressors,
extruders,
mixers, mills,
kneaders,
centrifuges,
separators

36. Siemens AG © 2012 Page 1 - 36
SITRAIN
Course DR-BD
The drives family SINAMICS
low voltage S, DCM and medium voltage
Low voltage converters Direct voltage
Medium voltage
conv.
For Basic Servo
applications
High Performance DC applications
Applications with high
outputs
S110 S120 S150 DCM
GH180/GM150/
SM150/GL150/ SL150
0,12 … 90 kW 0,12 … 5700 kW 75 … 1200 kW6 kW… 3 MW 0,15 … 120 MW
Single-axis
positioning
applications for
machine
and plant
engineering
Packaging
and textile
machines,
printing
presses,
machine tools,
plants,
process lines,
rolling mills
Test stands,
cross cutters,
centrifuges
Rolling mill
drives,
wiredrawing
machines,
extruders and
kneaders,
cableways and
elevators, test
stand drives
Rolling mill
drives, wiredrawing
machines,
extruders and
kneaders,
cableways and
elevators, test
stand drives

37. Siemens AG © 2012 Page 1 - 37
SITRAIN
Course DR-BD


M
Power unit
=
Power Module PM
Control
=
Control Unit CU
Operator panel
=
Operator Panel OP
Inverter
Modular inverter
Design of the SINAMICS G120