PET is used in traction system in order to reduce the size and increase performance of traction system

1. REDUCING THE SIZE OF ELECTRIC
RAILWAY LOCOMOTIVE BY USING
POWER ELECTRONICS TRANSFORMER
Submitted to:
Dr. Shushma Gupta
Professor
EE Department
Submitted by:
Rajat Kumar Keshari
172113216
ED

2. CONTENT
INTRODUCTION
HISTORY
BLOCK DIAGRAM OF A TRACTION SYSTEM
FEATURES OF A TRACTION SYSTEM
POWER ELECTRONICS TRANSFORMER(PET)
COMPARISON BETWEEN PET AND LFT
DIFFERENT PET BASED TRACTION SYSTEMS
KEY CHALLENGES
PROS AND CONS
FUTURE SCOPE IN INDIA
CONCLUSIONS
REFERENCES

3. INTRODUCTION
RAILWAY is the one of the most popular and widely used
ways for massive public transportation.
The modern trends towards high speed, distributed
propulsion by electrical multiple units and increased
passenger comfort require traction system with higher
efficiency lower weight and volume.
One of the major obstructs in the conventional line
frequency transformer are bulky and heavy due to the
nature of low operating frequency even with its
efficiency.
Electric traction is meant for locomotive in which the
driving (tractive) force is obtained from electric motors .
For traction purpose mostly three phase induction
motors and dc series motors are used.

4. HISTORY
The year 1881 saw the birth of the first electric railway run by
a German engineer Werner Van Siemens.
In 1953 25 KV dc traction system adopted as standard in
France but at that time Paris already electrified .
In 1990 high speed trains began to use lighter , lower
maintenance three phase AC induction motor.
The world’s first AC locomotive in Valtelina in northern Italy.
With 3 phase 15Hz 3KV AC motor.
In 2012, ASEA Brown Boveri (ABB) successfully tested PET
based Traction system on a locomotive in Switzerland.

5. CONT….
Electric traction was introduced on Indian Railway in
year 1925 on 1.5KV DC and the first electric train ran
between Bombay’s Victoria Terminus and Kurla
along the Harbour line of CR on 3rd February 1925
In the year 1957 Indian Railways decided to adopt
25KV AC traction based on French Railway’s SNCF
technology.

6. PET BASED LOCOMOTIVE
Google Images

7. SCHEMATIC DIAGRAM OF TRACTION
(USING DC MOTOR)
GOOGLE
IMAGES

8. BLOCK DIAGRAM OF LOCO MOTIVE

9. FEATURES OF TRACTION SYSTEM
High starting tractive effort to have rapid acceleration.
Higher power but reduced weight and volume(high
power density).
Higher efficiency.
Better reliability and reduced maintenance.
Easy speed control.

10. POWER ELECTRONIC TRANSFORMER
(PET)
 Conventional transformer is a device which shift a
voltage level to an other voltage level at same frequency
both side.
Induced EMF in a transformer is directly proportional to
supply frequency.
So in a power electronic transformer we increases the
frequency more than line frequency in mid frequency
range (400hz).
The size of this type of conductor reduced much due to
less use of cupper conductor.
The efficiency of transformer also increases .
By using cyclo convertors we can increases the
frequency of line frequency.

11. COMPARISON BETWEEN PET
AND LFT BASED TRACTION
Line transformer based Power electronic transformer based
Reference- 1

12. PET BASED TRACTION SYSTEM
Transformer is operating with mid frequency range
(100HZ-10KHZ)
Since the front end convertor is directly connected to
the catenary ,its need to withstand highest voltage so
need high voltage power devices.
Due to limited switching frequency of high voltage
power devices the terminal voltage of MFT usually are
pulsed but not sinusoidal.

13. PET BASED RAILWAY TRACTION
SYSTEM DEVELOPED IN 1985
Reference- 4

14. CONT…
This pet system is developed by the University of Leoben
Austria for 15KV ,16.6Hz.
 It consists of an input rectifier a matrix convertor , an
MFT an output rectifier and DC –DC booster convertor.
There is no dc bus capacitor after the input rectifier .
Transformer operated at 400Hz and using thyristor.

15. MULTILEVEL PET BASED
TRACTION SYSTEM
1998
Reference- 5

16. CONT…..
This pet concept was developed by Siemens in which
IGBTs are used at the place of thyristors .
IGBT are fully controlled devices while thyristers are
partially controlled device.
However in order to withstand the catenary voltage ,the
input power modules are connected in series and form a
multilevel convertor.
Whole system has input series and output parallel(ISOP)
configuration.

17. 3-PHASE IGBT BASED MATRIX
PET TRACTION SYSTEM
2001
Reference- 7

18. CONT…….
In this PET system thyristors are replaced by high
voltage IGBTs.
So the drawback of naturally commutation thyristor
convertor such as high switching losses, low switching
frequecy and high line current harmonics can be greatly
avoided .
This system may be single phase or 3 phase ,but 3 phase
preferred due to reduced line current harmonics .
At that time 6.5KV IGBTs are only available.

19. MATRIXCONVERTORBASEDPET TRACTION
SYSTEM
2008
Reference- 10

20. CONT….
This PET traction system was developed by the
University of West Bohemia ,Czech.
The MFT is operated 400Hz and has multiwinding .
The voltage and current waveform during startup steady
state operating and step change of load are validated the
feasibility oh the control algorithm.
It have good dynamic performance and is able to
overcome unbalance voltage fault.

21. CURRENT SOURCE PET BASED
TRACTION SYSTEM
2014
Reference- 2

22. Cont……..
This PET traction system is developed by North Carolina
State University USA.
It is a current source PET traction system.
It consists of the front end and output full bridge
convertors as well as high frequency fly-back
inductor(transformer) and output convertor connected in
parallel.
The galvanic isolation and voltage adoption are realized
by the high frequency fly- back invertor.

23. DIODE CLAMPED 3 LEVEL
MULTIMODUL PET SYSTEM
2015
Reference- 5

24. Cont…….
This PET based traction system developed by Laboratory
of Magnetic Suspension Technology and Maglev Vehicle
And Southwest Jiaoteng University china .
Each module is composed of a 3 level H-bridge ac-dc
rectifier and a half bridge bidirectional dc-dc convertor .
For commercial high power multi level convertors ,CHB-
based designed reach higher voltage and power level as
well as more mature than diode clamped convertors.

25. KEY CHALLANGES
High voltage power devices.
High power MFT.
System topologies.

26. PROS
Greatly reduced the volume and weight of
transformer .
Higher transformer and system efficiency.
Better power quality such as power factor,
harmonics and transient performance.
Improve power flow control, voltage swell and
sag.
Multi –voltage interface and fault isolation.

27. CONS
High input voltage for front convertors.
Higher system cost.
Complex design and manufacturing.
Reduced reliability.

28. FUTURE SCOPE IN INDIA
• In India the total length of railway track 66000
km and 20460km (near about) are electrified
tracks.
• World position is 4th.
• Research Design And Standards
Organization(RDSO) Lucknow are tries to
developed the model of locomotive with
compact size and high speed.
• But due to more costly PET transformer did not
used in India till now.

29. CONCLUSION
Various PET based railway traction system have been
comprehensively reviewed . The pros and cons the state
of art, future trends , challenges and opportunities of
PET based traction system are highlighted.
Although the PET based system are still developing but
they are already superior than the LFT based traction
system in term of power density, efficiency, power
quality, and functionalities and hence will be the future
for railway traction.

30. REFERENCES
1. Jiangua Feng, W.Q. Chu, senior member IEEE, Zixue Zang and Z. . Zhu,
Fellow, IEEE “ POWER ELECTRONICS TRANSFORMER BASED RAILWAY
TRACTION SYSTEM” September 2017.
2. P.Jain, M.Pahlevaninezhad,S.Pan and J. Drobnik “A review of high frequency
power distribution systems for space, telecommunication and computer
applications”, IEEE trans. Power electronics , vol. 29, no. 8, August 2014.
3. J.D. vam wyk and F.C. Lee, “ On a future for power electronics”’ IEEE J.
Emerg. Sel. Topic power electronics, vol. 1,no. 2, June 2013.
4. W. McMurray, “ Power converter circuits having a high frequency link”, U.S.
Patent .June 23 ,1990.
5. T. Strasser , “ A review of architectures and concepts for intelligence in
future renewable electric energy systems,” IEEE Trans. Ind. Electron ,Apr.
2015.
6. K. Harada , F. Anan , K. Yamasaki , M. Jinno , Y. Kawata and T. Nakashima , “
Intellegent transformer,” in proc. IEEE Power Electronics Specialist Conf.
(PESC), June 1996.

31. Continu….
7.R.K. Gupta , K.K. Mohapatra , and N. Mohan, “ A novel three-phase
switched multi-winding power electronic transformer,” in Proc. IEEE
Energy Conversions, September 2009.
8. M. Cacciato , A. Consoli, R. Attanasio, and F. Gennaro , “ Soft
switching converter with Hf transformer for grid-connected
photovoltaic systems,” IEEE Trans. Ind. Electron. Vol. 57, May 2010.
9.J. Taufiq , “ Power electronic technologies for railway vehicles,” in
Proc. Power Convers. Conf. (PCC) , Nagoya, Japan, Apr. 2007.
10. A.Prasai, J. S. Yim , D. Divan, A. Bendre, and S. K. Sul, “ A new
architecture for offshore wind farms ,” IEEE Trans. Power Electron. ,
May 2008.