This work was part of Research Work that we did under the Guidance of Dr. Praveen Kumar, Dept of EEE , IIT Guwahati from Feb'12 - May-2012. The Paper was then Published in IEEE Indiconn 2012, Kochin, Kerela as Conference Proceedings.

1. TechEnvince 1.0
Vivek Gunawat
Dharmendra Prajapati
Final Year Undergraduate, EEE, IITG

2. Authors
Authors
Webmail IDs
[@iitg.ac.in]
Mahesh Kumar
k.mahesh
Vivek Gunawat
v.gunawat
Surendra Swami
s.swami
Dharmendra Prajapati
d.prajapati

3. Title
“Analysis of Implementing the Electric
City Bus and its Coordination with the
Grid”

4. The Idea
• The idea can be divided into two parts:
• Part-1: Using supercapacitors as a power source
• Part-2: Using Energy Storage System at the bus
stops [Eg. VRBs]

5. The Concept
• Proposing an eco-friendly Transportation
system where Electric Bus would be the means
of transportation.
• Each Bus Stop will have Vanadium Redox
Batteries as the source for powering up the EVs.
• VRB (Vanadium Redox Batteries) are used for
dual purpose of supporting the grid and as well
as use it to support the transportation System

6. The Bus
• The Electric Vehicle that will be used will have
the following dimensions:
• Capacity : 20-30 Passengers
• Weight = 10,000 Kg
• Battery Type: Ultra/Super Capacitors
• Li-Ion Battery Pack for Emergencies

7. Why Supercapacitors ?
•
•
•
•
•
•
They have long life of >15 years
High Charging Rate/ Discharging Rate
Best Efficiency
Low System Costs
Easy to Maintain
Light Weight System

8. Why Supercapacitors ?
Image Courtesy : Maxwell Technologies

9. Supercapacitors
Image Source : Vina Technology Co. Ltd (South Korea), Maxwell Corp

10. Applications of Super Capacitors
Image Courtesy : Maxwell Technologies

11. The Capabus
Image Courtesy : MAN Truck & Bus AG, Munich, Germany

12. The Bus Stop
• There will be in total 30 Bus stops on the
proposed ring road of 47.5 Km
• Each Bus Stop will have VRBs installed.
• VRBs will be charged through 33kV or 11kV
connection from the main grid.
• Grid Peak Hours are from (0800-1200 hrs.) and
(1600-2000hrs.)
• Grid off-Peak Hours are from (2200-0700 hrs.)

13. Ring Road
• As described, the ring road will be in total of 47.5
Km, covering the area of Guwahati Electric
Circle -1 and Electric Circle -2 which covers 80%
of Urban and 80% of Rural areas of Guwahati
City Respectively.
• The proposed ring road is from Jalukbari
Chowk- maligaon – Fancy Bazar – Ullubari –
Dispur- Khanapara- Lalmati – LokhraSajusajai- and back.

14. The Ring Road
Image Courtesy : Vivek Gunawat

15. Problem Formulation
• There was a need for calculation of different
parameters such as Energy Requirement for the
Bus, and then deciding the capacities of VRBs
and Super Capacitors accordingly.
• These will be discussed in the following slides
under:
• Calculation of Energy using NYCC
• Calculation of Total Energy for the System

16. Calculation of Energy using NYCC
• The energy required by a Capabus is calculated
by assuming the mass of the bus is 10 tons
(10,000 kg), its length is 10 m, width is 2m and
height is 3m.
• The Movement of the bus between two stops will
depend on the traffic condition of the city. If
traffic is high then rapid acceleration and
braking is necessary.

17. Time Graph of NYCC
The figure : Test simulations of low speed urban driving with frequent
stops
Image Courtesy : EPA New York City Cycle

18. Time Graph of NYCC
• Graph shows the speed of the Capabus with
respect to time. The duration of one cycle is 600
seconds, distance travelled is 1.90 km and
average speed is 11.4 km/hr.

19. Calculation of Energy using NYCC
• Motion of the bus will be opposed by various
resistive forces which are mentioned below.
(Assumption: road angle (  is zero)).
1. Rolling Resistance
Froll  fr gM
• Where M = 10,000 Kg [Mass of the Bus]
• g = 9.8 m/s2 [Gravitational Acceleration
Constant]
• fr  0.01 [rolling resistance coefficient]

20. Calculation of Energy using NYCC
2. Aerodynamic resistance (Faero)
Faero
1
 Af Cd V 2
2
Where
•  - Density of air
• Af - Frontal Area of the bus
• Cd - Drag Coefficient

21. Calculation of Energy using NYCC
3. Acceleration Resistance (Facce)
Facce
dV
 M
dt
Where,
•  Is the Rotational Inertia = 1.1.
• M is Mass of the Bus.
• dV Is the acceleration of the bus.
dt

22. Calculation of Energy using NYCC
• Work done by the engine against aerodynamic
force is 0.023kWh
• Work done Against rolling resistance is
0.223kWh and against acceleration resistance is
1.663kWh.
• The total work done by the engine to travel 1.9
km is equal to 1.304kWh [Assuming 40% Kinetic
Energy is recovered during braking].

23. Power Curve

24. Specification of VRBs
Variable
Energy
Capabus)
Value
ratings
(For 1.373 KWh
Energy ratings of one stack 90 KWh
of VRB
Rated DC Voltage
125V
Rated DC current
370 A
DC Voltage Range
100-155V

25. Dimension of One Supercapacitor
• C = 70F
• Operating Voltage = 2.1 V dc
• 0.1 Ohm, at 1 KHz
• Physical Dimensions:Diameter - 18mm
Length – 50mm

26. Method of Charging between
Charging Station & Capabus
• The charging of EVs is done using the method
of 'Contactless Charging' or 'Inductive
Charging' in which the super-capacitors in
the EVs would be charged by the VRBs using
this technique.
• The Energy here will be transferred through
inductive coupling from VRBs at the charging
station to supercapacitors inside EVs.

27. Inductive Charging System

28. Result & Analysis
• This system implementation shows that there is
an improvement of the load profile because of
valley filling and peak shaving.

29. Curve of Voltage per unit(Vpu)

30. Conclusion and Future Works
-The Need
• Current Vehicles uses fuels like Petrol, Diesel,
CNG etc..
• The natural resources are depleting day by day
and there is an immediate need to find
alternative solutions for powering up the
Vehicles which are eco-friendly in nature
• Hybrid Vehicles are examples of solutions, but a
totally independent solutions are Electric vehicle

31. Conclusion and Future Works
• The intention of using VRBs and super
capacitors in this work is that both are energy
efficient, has high charge transfer rate and are
economically viable as well as environmentally
safe.
• VRBs will also be used to support the grid during
peak hours

32. Conclusion and Future Works
• Our next work, the detailed design of the
Capabus and charging station will be studied
along with the analysis of the grid support by
Vanadium Redox Batteries during peak hours.
• The feasibility of the VRBs and the Capabuses
will be analysed for the real time
implementation on the city of Guwahati, the
state capital of Assam

33. References
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[1] Sekyung Han,student member IEEE, Soohe Han, member,IEEE, and Karou sezaki, member
IEEE, “Development of an Optimal Vehicle-to-Grid Aggregator for Frequency regulation,” in
IEEE TRANSACTIONS ON SMART GRID,VOL.1, NO.1,JUNE2010.
[2] Vuhic, Vukan R. “Urban transit system and technology,” John Wiley & sons, Hoboken,
NJ.2010.p.69.
[3] A. F. Burke, “Cost-effective combinations of ultra- capacitors and batteries for vehicle
applications”, presented at the Second Int. Advanced Battery Conf., Las Vegas, NV, Feb. 4–7,
2002.
[4] Super capacitor specifications Cornell Dubilier Inc.
www.cde.com/catalogues.
[5] IC Illinois, Super capacitors”www.illcap.com”.
[6] M. Singh, P Kumar, and I Kar “Implementation of Vehicle to Grid Infrastructure Using
Fuzzy Logic Controller",IEEE Transaction on Smart Grid, Vol. I, issue 1, pp. 565-575, March 2012.
[7] J.Chavan, C. Abbey, M.Chamberland, G.Joos, “Battery Storage System Modelling , Design
and Operation for Wind Energy Integration in Power Systems,” CIGRE Canada Conference on
Power Systems, Aug-2007.
[8] M.H. Li, T. Funaki and T. Hikihara, “A Study of Output Terminal Voltage Modelling for
Redox Flow Battery Based on Charge and Discharge Experiments,” Fourth power conversion
conference, April,2007, pp.221-225.
[9] Bus Specification (pg-16)Tindo Electric Bus and Recharging Infrastructure.pdf.

34. References
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[10] Hao Qian, student Member, IEEE, Jianhui Zhang, JihSheng(Janson) Lai, Fellow, IEEE, and Wensong Yu, Member, IEEE, “A High Efficiency Grid-Tie
Battery Energy Storage System,” in IEEE transactions on power electronics , vol.26, no.3, march 2011.
[11] Y.S. Lee and M.W. Cheng, “Intelligent control battery equalization for series connected lithium-ion
battery strings,” IEEE Trans. Ind.Electron.,vol.52,no.5,pp. 1297-1307, Oct.2005.
[12] [Online] www.technologyreview.com/news/415773/next-stop-ultracapicitor-buses/
[13] P.F. Ribeiro, B.K. Johnson, M.L. Crow, A.Arory, Y.Liu, “Energy Storge Systems for advanced power
applications,” peoceedings of the IEEE, vol.89, Issue 12,Dec.2001 pp.1744-1756.
[14] Y.Zhong; J. Zhang; G. Li; A. Liu “Research on Energy Efficiency of Supercapacitor Energy storage
system,” International conference on power system technology, power Con 2006, Oct.2006,4 pp.
[15] A. Payman, S. Piefederici, and F. Meibody-Tabar, “Energy Management in a fuel cell/super capacitor
multisource/multi load electrical hybrid system,” IEEE Trans. Power Electron., vol.24, no. 12, pp.26812691, Dec. 2009.
[16] ASEB, Assam State Electricity Board Guwahati, India. Available: http://aseb.in/, 2012.
[17] Guwahati Electric Circle-1 and Guwahati electric
circle-2 taken from assam power
distribution company limited ”http://www.mybijulibill.com/about_GEC1_profile.jsp”.
[18] EPA New York City Cycle (NYCC),”www.dieselnet.com”.
[19] For the VR Battery specifications, CESI Italy, www.iset.unikassel.de/dispower_static/documents.

35. Publication
• Paper was presented at INDICON – 2012,
Kochin, Kerela
• And Published in IEEE Conference Proceedings,
available on IEEE Xplore

36. Thank You
Questions are Welcomed