TechEnvince - Analysis of Implementing the Electric Bus and its Coordnation with the Grid

TechEnvince 1.0

Vivek Gunawat

Dharmendra Prajapati

Final Year Undergraduate, EEE, IITG

Authors

Authors Webmail IDs [@iitg.ac.in]

Mahesh Kumar k.mahesh

Vivek Gunawat v.gunawat

Surendra Swami s.swami

Dharmendra Prajapati d.prajapati

“Analysis of Implementing the Electric

City Bus and its Coordination with the

Grid”

Title

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]

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

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

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

Why Supercapacitors ?

Image Courtesy : Maxwell Technologies

Supercapacitors

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

Applications of Super Capacitors

Image Courtesy : Maxwell Technologies

The Capabus

Image Courtesy : MAN Truck & Bus AG, Munich, Germany

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.)

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 – Lokhra- Sajusajai- and back.

The Ring Road

Image Courtesy : Vivek Gunawat

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

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.

Time Graph of NYCC

Image Courtesy : EPA New York City Cycle

The figure : Test simulations of low speed urban driving with frequent

stops

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.

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

• Where M = 10,000 Kg [Mass of the Bus] • g = 9.8 m/s2 [Gravitational Acceleration

Constant] • [rolling resistance coefficient]

0.01rf

roll rF f gM

Calculation of Energy using NYCC

2. Aerodynamic resistance (Faero)

Where

• - Density of air

• Af - Frontal Area of the bus

• Cd - Drag Coefficient

21

2aero f dF A C V

Calculation of Energy using NYCC

3. Acceleration Resistance (Facce)

Where,

• Is the Rotational Inertia = 1.1.

• M is Mass of the Bus.

• Is the acceleration of the bus.

acce

dVF M

dt

dV

dt

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].

Power Curve

Specification of VRBs

Variable Value

Energy ratings (For Capabus)

1.373 KWh

Energy ratings of one stack of VRB

90 KWh

Rated DC Voltage 125V

Rated DC current 370 A

DC Voltage Range 100-155V

Dimension of One Supercapacitor

• C = 70F

• Operating Voltage = 2.1 V dc

• 0.1 Ohm, at 1 KHz

• Physical Dimensions:-

Diameter - 18mm

Length – 50mm

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.

Inductive Charging System

Result & Analysis

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

Curve of Voltage per unit(Vpu)

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

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

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

References

• [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.

References

• [10] Hao Qian, student Member, IEEE, Jianhui Zhang, Jih- • Sheng(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.2681-2691, 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.

Publication

• Paper was presented at INDICON – 2012, Kochin, Kerela

• And Published in IEEE Conference Proceedings, available on IEEE Xplore

Thank You

Questions are Welcomed