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Abstract In the Laboratory of Kathmandu University first timein Nepal research on Battery Powered three wheeler was conductedto encourage the use of clean and green energy. The performance ofthe vehicle is also studied. The fabricated vehicle uses a 750W/ 48VBLDC Hub motor that is powered by four 12 Volt, 40 AH batteries.A six-step motor controller controls the operation of the motor,

braking and acceleration system are also associated with the motorcontroller which aids in the operation of the motor. The performanceof the vehicle was found to be satisfactory for the load of two peoplein 10 degree gradient surfaces with the average speed of 20 km/h.However, it still needs modifications and improvements.

Keywords EV , Inverter & BLDC.

I. I NTRODUCTIONHE fossil fuel such as petrol and diesel have beenextracted and used in an erratic and expensive way. The

use of fossil fuel based vehicles is one of the major ways thathas accelerated the extraction of these non-renewableresources in an unsustainable way. Further, transportation ofthese fuel to rural communities itself has become a major

problem. Therefore, it is high time for researching andengineering new technology for replacing the current practicewith the alternative energy such as solar power. Therefore, thestudents of Kathmandu University (KU) have developed aresearch project to build a Solar- Powered Vehicle (SPV)which is expected to be economical than to the petrol runningvehicles but here it will be emulated by 48Volt battery. Solar-

powered vehicle will be a power generating and storingvehicle. It will use solar panels to extract the solar energythrough photo voltaic cells. The generated energy will bestored in Lead-acid batteries and these batteries will be pairedup in series to increase the capacity and thus the mileage ofthe Vehicle. These Vehicles are expected to ensure a mileageof 50 km with 48 Volts of battery with full capacity.

The solar-powered Vehicle will include a solar panel, ahub motor, battery storage, charge controller, motor speed

controller circuit and a power electronic circuit allowingdifferent switching as well as an access to external AC powerwhich would help the vehicle to charge during the night. Thewise side of this project will be the inclusion of pre-existing

1Aasish Pradhan , M.Sc. Student University of New South Wales, Kensington NSW 2052 Australia. Email [email protected] 1Bibek Man Shrestha , M.Tech. Student J.N.T.U ,Kakinad, Andra Pradesh,

India, Email [email protected] 2 Lalit Bickram Rana Phd Student in Lappeenranta University of Technology,Lappeenranta, Finland Email. [email protected]

pedal (considering a tricycle or rickshaw) which will allowthe rider to use the Vehicle the old-school way. In order tomake it a commercial product it can also include a headlight, amobile charging circuit, and other luxuries if possible.

II. SYSTEM OVERVIEW The Fig.1 represents an overall view of the electrical system

of SPV. The DC power supply of this system consists of twodifferent supplies. Amongst these, one is the DC powerderived from solar panel and another is the rectified ACsupply. The power supply is connected to the battery bankthrough the charge controller.

Fig. 1 Overall View of the System

The charge controller is also connected to the motorcontroller which is connected to the motor. The chargecontroller controls the Depth of Discharge (DOD) of the

battery in order to maintain the life of the battery. The motorcontroller can be used to control both the speed and itselectrical braking. These functions could be achieved withelectrical throttle and electric braking switch.

III. MOTOR DRIVE FOR THE VEHICLE

Selection of electric motor drives for EVs is a veryimportant step that requires special attention. The basicrequirements are summarized as follows: high instant power and a high power density high torque at low speed for starting and climbing, as well

high power at high speed for cruising very wide speed range with constant-power region fast torque response high efficiency over the wide speed range with constant

torque and constant power regions high efficiency for regenerative braking downsizing, weight reduction, and lower moment of inertia

Development of Small Battery Powered ThreeWheeler Using PM Hub Motor Prototype I

A.Pradhan 1, B. M. Shrestha, 1, L.B.Rana 2

TBatteryBank

ChargeController

MotorController PMBLDC

DC PowerSupply

Accelerator

ElectricalBraking

International Conference on Electrical, Electronics and Civil Engineering (ICEECE'2011) Pattaya Dec. 2011

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the battery voltage reaches at 54 V while charging, thecharging circuit is cut off. While supplying power to themotor when the voltage reaches 44 V, the supply to the motoris cut off and the charging circuit is connected again.

Fig..3 Charge Controller

VI. MOTOR CONTROLLER

The simple motor-drive model of a BLDC motor-headerconsists of a three-phase power stage plus a brushless DCmotor as shown in Fig.4. The power for the system is

provided by a voltage source (U d ). Six semiconductorswitches (SA/B/C t/b) allow the rectangular voltagewaveforms to be applied. The semiconductor switches anddiodes are simulated as ideal devices. The trapezoidal controlof the BLDC motor is based on energizing only two phases ata time.

This means that one top and one bottom semiconductorswitch are turned on, each in a different phase. Thus the last

phase has both top and bottom switches switched off and is

disconnected from the voltage source. Considering all possibilities, it will provide six possible combinations toenergize two phases in the three-phase system. Therefore thistechnique is also called a six-step control. The most commonway to control a BLDC motor is to use hall sensors todetermine the rotor position.

The control system senses the rotor position and the propervoltage pattern are applied to the motor. The motor andcontroller used in EV is a three phase BLDC Hub motor

produced by Electro herm Limited of India.

VII. PRODUCT DESCRIPTION The chassis in Fig. 5 has been designed to support the

weights given in Table II. The chassis designed is an invertedT-shaped structure with one front tire and two rear tires. Thesteel that has been used is a 4 cm square hollow steel. Thesekinds of steels have been extensively used in heavy duty metalworks. These steels also have the advantage of less weight dueto the hollow space inside the main frame. The chassis has alength of 150 cm and a breadth of 80 cm. The peak output

power of the motor is 750 Watts and runs at a voltage of 48Volts shown in Fig.6. The motor has a diameter of 23cm anda thickness of 50 mm.

Fig. 4 VSC Fed PMBLDC

Fig. 5 Chassis of Three Wheeler

Differential action in a vehicular system allows a vehicle toturn both at rest and during motion. These actions are

performed by a differential system present in the vehicle.TABLE II

(WEIGHT OF DIFFERENT PARTS )

Rider 140 Kg (2 persons)

Battery 20 KgOther Parts 2 KgWeight margin 15 KgTotal weight 177 kg

The differential system used in this vehicle consists of thetwo bearing placed at the two rear tires of the system. These

bearing help to obtain the necessary differential action. Whenthe vehicle is turned in left direction, the bearing at the left tirecomes to rest and the bearing at the right becomes free torotate with the inertia and vice-versa. And hence, differentialis obtained. The prototype is shown in Fig.7

Fig. 6 Wheel of Three Wheeler


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Fig. 7 Prototype Developed in Laboratory

The battery charger consists of a transformer of 220/18Vand four batteries each of 12 V. The charging current for eachof the battery lies between 2-3 Amps. Hence for the Powerdrawn by during charging = 144 Watts. Charging duration = 8hrs, Watt-hour rating = 1152 watt-hour = 1.152 KWH

According to Nepal Electricity Authority the tariff forenergy use per KWH is Nrs 7.4. Hence the price to fullycharged vehicle is NRs 8.5248

Here the distance covered by the vehicle in a single day is40 km when the battery is fully charged. Then cost per kmtravelled in a single day for 40 Km will be NRs 0.213 or 20

paisa per km.If the price is compared to petrol driven two wheeler

vehicles, the cost per km travelled will be Nrs 2.1 (considering price of one liter of petrol to be NRs 84, Nepal OilCorporation)

VIII. CONCLUSION

The project on EV has been satisfactorily completed the prototype vehicle can run in normal dry surface with amaximum speed of 30 km/h with a total weight of 177 kg. Thevehicle can show satisfactory results on slope less than 15.When the battery of the vehicle is fully charged it can runcontinuously at an average speed of 20 km/h for two hourswith an average running cost of 20 paisa per km. Further,vehicles such as EV could be made genuinely sustainable bygenerating your own electricity with mounted solar panelarray resulting into zero fossil fuel consumption.

IX. APPENDIXA NALYTICAL COMPUTED VALUES

Total weight 430 kg Radius of wheel 0.33 m Maximumforce

1247.525 N Shaft speed 160 rpm

Force in Plane 386.854 N Max. Power 1.2KW Max.Torque 62.37 Nm Min. Power 0.43KW Min. Torque 21.37Nm Over all Loss 20% Velocity 5.555 m/s Peddling Power 0.212KWSystem Volt 48V Motor Power 1KW

R EFERENCE S[1]Iqbal Husain Electrical and Hybrid Vehicles Design Fundamentals by

CRC PRESS Boca Raton London New York Washington, D.C.[2]T.J.E. Miller Brushless Permanent Magnet and Reluctance Motor Drive

Clarendon Press Oxford 1989[3]Ned Mohan Tore M. Undeland and William P. Robinson Power

Electronics Converters application and Design third edition John Willy& Sons , Inc

[4] Jacek F. Gieras , Rong-Jie Wang and Maarten J. Kamper Axial Flux

Permanent Magnet Brushless Machines Kluwer Academic PublishersDordrecth Boston London[5]Juha Pyrhnen , Tapani Jokinen and Valeria Hrabovcova Design of

Rotating Electrical Machines John Willy & Sons , Inc[6]Jos R. Rodrguez et all PWM Regenerative Rectifiers: State of the Art

IEEE Transactions on Industrial Electronics, Vol. 52, No. 1, February2005

[7]C.m. Ong Dynamic Simulation of Electrical Machinery Using Matlab /Simulink Prentice hall 1998

[8]Wen L. Soong et all Field-Weakening Performance of InteriorPermanent-Magnet Motors , IEEE Transactions on IndustrialApplications, Vol.38, No. 5, September /October 2002

[9]Gi-Taek Kim and Thomas A. Lipo VSI-PWM RectifiedInverter Systemwith a Reduced Switch Count IEEE Transactions on IndustrialApplications,Vol.32,N0. 6, November / December 1996

[10]Thomas Finken et all Comparison and design of different electricalmachine types regarding their applicability in hybrid electrical vehicles,Proceeding of the 2008 International Conference on Electrical MachinePaper ID 988

A. Pradhan has received B.E. Electrical and Electronics from KathmanduUniversity Nepal in 2010. Currently he is M.Sc. Student in School ofElectrical Engineering and Telecom. University of New South WalesKensington NSW 2052 Australia B.M. Shrestha has received B.E. Electrical and Electronics from KathmanduUniversity Nepal in 2010. Currently he is pursuing M .Tech. in High VoltageEngineering, Jawaharlal Nehru Technological University Kakinada AndraPradesh IndiaL.B.Rana has completed his B.Sc. Engineering Electrical and Electronicsfrom the Bangladesh University of Engineering and Technology DhakaBangladesh and M.E with Specialization in Power Electronics and Drivesfrom Anna University Chennai India. His interest is Motor Drive. Currently heis working as Assistant Professor in the EEE Department of KathmanduUniversity Nepal and Phd Student in Lappeenranta University of TechnologyLappeenranta Finland


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