Compares Design of the 3 KW with 350 Watt Electric Motor Cycle

H. Helmi Rangkuti

, R. Harahap

, Suherman

, and Yusmartato

Electrical Engineering Department, Universitas Sumatera Utara, Indonesia

Faculty of Engineering, Universitas Islam Sumatera Utara, Medan, Indonesia,

Keywords: electric motorcycle, design, electrical wiring.

Abstract: This paper presents an initial design of the electric motor that employed maximum power source of 3 kW.

The research found that initial motor capacity is not easy found as torque is affected by mechanic and

passenger masses and the rotation per minute (rpm) is affected by gear arrangement. However, initial device

collection has been conducted including a battery size determination, motor controller, mechanics, and

speedometer as well as wiring requirement. Design is started by the power source calculation, the electric

motor specification, electric motor controller, electrical wiring, motor-wheel connection and transmission,

and mechanical frame. Further work will focus on the assessment of motor capability to move electric

motorcycle with given passenger and motor weight.

1 INTRODUCTION

As the essential transport, motorcycle is commonly

used in tropical country such as in Indonesia as the

weather is not friendly for pedestrian as well as

providing small transport capacity. Number of

motorcycle runs in the Indonesian road reaches 85

million according to the AISI (AISI, 2018).

It can be said that all the running motorcycle in

Indonesia use petrol as the power source. It was

found that the petrol requirement in Indonesia

reaches 1.6 million barrel per day (B. Migas, 2017).

It can be thought that the usage of the fossil energy

is inefficient as its greater than national product

about 834 thousand barrel per day(B. Migas, 2017).

Therefore alternative solutions are required. A more

friendly fuel is needed. The liquid gas based public

transport has been provided by the government. It

can be found that some buses available in Jakarta

use liquid gases. However, the secure of this fuel

usage remains a problem. Despite, this challenge,

efforts should be made continuously as fossil energy

source decreases continuously.

The electric vehicles have been a warm issue in

efficient renewable energy driven transports. Many

researches exist and more are coming. Electric car

has been proposed in many ways, and the

competition challenges are also conducted in many

countries. For instance, Universitas Sumatera Utara

as the oldest University in Sumatra Island of

Indonesia, has been the winner some minimum

energy usage car competition (Ambarita; Siregarand

Kawai, 2018). The electrical engineering within this

university also participates in electrical vehicle

competition (Howlader, A. H; Chowdhury, N. A;

Faiter, M. M. K; Touati, F and Benammar, M. A,

2014).

This paper focuses on electrical motorcycle

design for student laboratory activities. Despite the

absence of the novel method, the implementation is

rather practical and useful for student experiment

purpose. The more academic research has been

conducted in (Buja, G; Bertoluzzo, M and Mude, K.

N, 2015); (Paterson, S; Vijayaratnam, P; Perera, C

and Doig, G, 2016). The designed motorcycle is

aimed at power source of 3 kW. In order to do so,

device components requirement is analyzed, starting

from the battery to the mechanical frame.

2 RESEARCH METHODS

In order to realize the expected electric motorcycle,

Figure 1 shows the design steps involved in this

research. Design is started by the power source

calculation, the electric motor specification, electric

motor controller, electrical wiring, motor-wheel

connection and transmission, and mechanical frame.

Rangkuti, H., Harahap, R., Suherman, . and Yusmartato, .

Compares Design of the 3 KW with 350 Watt Electric Motor Cycle.

DOI: 10.5220/0008882100410045

In Proceedings of the 7th International Conference on Multidisciplinary Research (ICMR 2018) - , pages 41-45

ISBN: 978-989-758-437-4

Figure 1: Research step.

The next step is component purchasing and

finally component assembly. By the time this paper

written, the designed electric motorcycle is not yet

finished and tested.

3 COMPONENT SELECTION

AND RESULTS

The next step is component purchasing and finally

component assembly. By the time this paper written,

the designed electric motorcycle is not yet finished

and tested. The torsion moment (momen putir, MP)

is calculated based on Equation 1 considering input

power P and rotation per meter (n):

 

60  

2  

1

The output power is determined by the work

done by the electric motor and the speed achieved.

Equation 2 shows the formula. The efficiency is

given by Equation 3.





  

(2)













(3)

The battery capacity is determined by the

Equation 4 where the charging duration (t) depends

on battery capacity (ampere hour, AH), battery

voltage (V) and the required power (P).





/

(4)

Battery should be able to store enough charge to

produce current for a specific time. Further battery

should not add significant mass to motor. In order to

do so, this research arranges 13 series and 5 parallel

Lithium battery of 3.7; 5AH to produce 48 V; 25

AH. Figure 2 shows the packed battery. And to

allow charging, a commercial 48 V and a 2 A

charger was purchased.

Multiphase brushless direct current (BLDC)

(Salehifar, M; Moreno-Eguilaz, M; Putrus, G and

Barras, P, 2016) is commonly motor used for

electric vehicle. BLDC motor does not use brush for

current supply. Permanent magnet (Figure 2) acts as

rotor. In order to move phase current, the motor

requires hall sensors to detect magnetic position. As

s result, BLDC requires a specific controller. Some

advantages of BLDC motor are, smooth torsion,

high efficiency, long lifetime, smooth working on

any speed.

Figure 2: BLDC motor.

In order to determine the motor requirement, the

power is calculated based on the approximated

passenger and motor masses. In this case, the

passenger mass is assumed to be one person with

65kg mass. The motor mass depends on the

mechanic, motor and battery masses. After making a

brief survey, this paper approximates the motor mass

is 20 kg. As the selected mechanic frames as shown

in Figure 3 with gear diameter 10 cm and 14 cm, 3 is

about 51.3 kg, the total approximated motorcycle

mass is 71.5 kg. There will be rotational per minute

ICMR 2018 - International Conference on Multidisciplinary Research

changes. The expected reduced rpm is

71.4%xRPM

motor

Figure 3: Motor mechanics.

The torque required [Nm] at the wheels is

Maximum force[N] x radius of the wheel [m]

T(wheel) = F x r

This has to be converted to the torque required at

the machine side, which is a ratio. Ignoring all

losses, power in = power out, but one can generally

allow for a loss of about 2% therefore,

T(motor) x w(motor) = T(wheel) x w(wheel)

where T is in Nm and w (angular velocity) is

measured in radians per second.

To include gearbox efficiency of 98% this

becomes

0.98 T(motor) x w(motor) = T(wheel) x w(wheel)

(you will need more torque at the motor side to

overcome the inefficiencies)

To convert rpm to radians per second: w = rpm x

2Pi / 60.

Without considering the weight of the motor

mechanics and the gear, the torque offered by BLDC

can be approximated as (Torque calculation, 2018):

  

/2

(5)

The total mass of passenger and motor is about

136.5 kg. This mass and torque relation is hardly

found as the efficiency changes to load. However,

by considering these problems and the expected

average speed of 35 km/h, initial decision is to

purchase a 400 rpm, 3 kW BLDC motor as shown in

Figure 4.

Figure 4: The 3 kW 48 V BLDC motor.

Battery should be able to store enough charge to

produce current for a specific time. Further battery

should not add significant mass to motor. In order to

do so, this research arranges 13 series and 5 parallel

Lithium battery of 3.7 5AH to produce 48 V 25

AH. Figure 5 shows the packed battery. And to

allow charging, a commercial 48 V and a 2 A

charger was purchased.

Compares Design of the 3 KW with 350 Watt Electric Motor Cycle

Figure 5: The packed Lithium battery and a charger.

Since BLDC requires hall sensor control, the

pulse width modulation controller in purchase to

enable duty cycle controlling as depicted in Figure 6.

Additional devices that have been purchased,

include a speedometer, motor cycle lighting and

other components.

Figure 6: BLDC controller.

BLDC motor control A BLDC motor can

overcome the shortcomings of the DC motor. The

basic structure of BLDC motor is different as

compared to DC motor because it has no mechanical

commutator (brush). In a BLDC motor, the coil is

wound on the stator, the rotor has surface-mounted

permanent magnets, and the brush commutator is

replaced with the electronic commutator. The

external rotor (some motors are internal) has four

pole pairs and consists of the permanent magnet.

The stator consists of three-phase windings (A, B,

and C). It is easy and intuitive to analyze magnetic

field of the stator using this schematic.The MCU and

the control circuit is the commutator.

The stator windings can generate the magnetic

field when powered, which will attract or repel the

permanent magnet (rotor), as a result of which the

rotor spins. See the following figure. Basic theory of

motor control BLDC Motor Control with Hall

Sensors Based on FRDM-KE02Z, Rev 0, 07/2013

Freescale Semiconductor, Inc. 5 Figure 6. Internal

magnetic force The following figure shows how to

generate the magnetic field in the stator. Here, the

positive current is defined as the current flowing into

a specific phase, or coming out of a specific phase.

Figure 7. Magnetic field generation Similar to the

DC motor, if the MCU and control circuit in a

BLDC motor do not change the direction of the

magnetic field generated by the stator windings in

ICMR 2018 - International Conference on Multidisciplinary Research

time, the rotor won’t spin. In BLDC motor, a

rotating magnetic field should be generated by the

windings. Therefore, there must be a way to

conform the position of commutation and change the

direction. For this purpose, the Hall sensor method is

discussed in this application note. 3 Basic theory of

six-step commutation method

4 CONCLUSIONS

This paper has reported the initial work on designing

a 3kW electric motorcycle. Initial motor purchased

BLDC is based on approximation as mathematical

analysis effected by the load and mechanical masses.

Battery, controller and mechanics have also been

collected. Further work will focus on the assessment

of motor capability to move electric motorcycle with

given passenger and motor weight.

ACKNOWLEDGEMENT

This research has been supported by the Penelitian

Talenta, funded by Universitas Sumatera Utara.

REFERENCES

AISI, “Domestic Distribution in 2018,” Indones. AISI -

Asos. Ind. Sepedamotor.

Ambarita, H., Siregar, M. R., and Kawai, H. 2018, March.

Study on aerodynamics characteristics an urban

concept car for energy-efficient race. In IOP

Conference Series: Materials Science and Engineering

(Vol. 343, No. 1, p. 012025). IOP Publishing.

B. Migas, “Konsumsi BBM Nasional,” 2017.

Buja, G., Bertoluzzo, M., and Mude, K. N. 2015. Design

and experimentation of WPT charger for electric city

car. IEEE Transactions on Industrial Electronics,

62(12), 7436-7447.

Howlader, A. H., Chowdhury, N. A., Faiter, M. M. K.,

Touati, F., and Benammar, M. A. 2014, March.

Development of energy efficient battery electric car

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Ene.

Paterson, S., Vijayaratnam, P., Perera, C., and Doig, G.

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Salehifar, M., Moreno-Eguilaz, M., Putrus, G., and Barras,

P. 2016. Simplified fault tolerant finite control set

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Compares Design of the 3 KW with 350 Watt Electric Motor Cycle