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Course Number:
ELEC 6491
Instructor:
Dr. Maher Al Badri
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Assignment
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Individual submission
Lab Report
Software
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Name:
Md. Sami Refayet
ID No:
27668600
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8-11-2016
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DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING
ELEC 6491: CONTROLLED ELECTRIC DRIVES
DESIGN OF AN ELECTRIC DC MOTOR VEHICLE
Submitted By
Name
ID
Course No
: Md. Sami Refayet
: 27668600
: ELEC6491
Submitted To
Submitted on
: DR. MAHER AL-BADRI
: 27/11/2016
3|P age
Table of Contents:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
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23.
24.
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28.
Abstract
……………………………………………………………….
Introduction
……………………………………………………………....
Machine Parameter
……………………………………………………………….
Vehicle Specifications
……………………………………………………………….
Acceleration Profile
……………………………………………………………….
Drive Cycle Definition
……………………………………………………………….
Inertia (linear & rotational)
……………………………………………………………….
Torque Component
……………………………………………………………….
Operating Envelope
……………………………………………………………….
Ratings of the component ……………………………………………………………….
Controller
……………………………………………………………….
DC-DC Boost Converter
……………………………………………………………….
DC-DC Buck Converter
……………………………………………………………….
Cable Size and Length Specification ………………………………………………………….
Sensor and Transducers
……………………………………………………………….
Selection of gear ratio
……………………………………………………………….
Schematic Diagram
……………………………………………………………….
Battery Bank
……………………………………………………………….
System Wiring Diagram
……………………………………………………………….
Parts Lisl
……………………………………………………………….
Controller Design
……………………………………………………………….
DC motor Block Diagram ……………………………………………………………….
Simulation on Matlab Simulink
……………………………………………………………….
Outputs (Voltage, Current, speed) ……………………………………………………………
Discussion
……………………………………………………………….
Conclusion
……………………………………………………………….
References
……………………………………………………………….
Data Sheets
………………………………………………………………
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List of Figures
Sl.No.
Description
Page number
1.1
The Route considered for the Drive cycle
8
1.2
Speed Distance curve of the Vehicle
9
1.3
(a)Speed Torque curve of the motor, (b)– Speed Torque curve of
11
the Vehicle
1.4
Schematic Diagram of the Electric Vehicle
12
1.5
Wiring Diagram of the Electric Vehicle
13
1.6
Block Diagram of Dc Motor
14
1.7
Matlab- Simulink model of current loop
15
1.8
Matlab- Simulink model of voltage output
16
1.9
Matlab- Simulink model of current
17
1.10
Output waveform of the armature speed
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Abstract:
In this report for a given motor specification an electric vehicle needs to be designed. We find out
the working gear transmission system in order to accelerate the vehicle. The operating envelope and
the drive cycle of the designed vehicle is determined. The second part of the report describes how the
electrical components such as the DC- Dc converter, sensor and controller are selected based on the
vehicle parameters. Then battery bank is selected based on the vehicle load requirement. In the
third part of the report the current loop of the vehicle is simulated and which shows the current and
voltage components.
Introduction:
Now a days motor drives are used almost in every moving electric drives. High performance position
controlled drives in robotics and variable speed drives andfor adjusting flow rates in pumps, we can
find the motor drives. In all drives, where the speed and position are controlled, a power electronic
converter is needed as an interface between the input power and the motor. In many applications,
open-loop operation of d.c. motors may not be satisfactory because the speed changes if the firing
angle is kept constant and the torque applied to the d.c. motor is increased. However, if the drive
requires constant-speed operation the firing angle has to change to maintain a constant speed. This
can be achieved in a closed-loop control system. The closed-loop control system has the advantages
of improved accuracy, fast dynamic response, and reduced effects of load disturbances and system
nonlinearities.
When the drive requirements include rapid acceleration and deceleration, closed-loop control is
necessary. The system can be made to operate at constant torque over a certain speed range. In
practice, most industrial drive system operates on closed-loop feedback system.
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Part-1 Design Specification
Machine parameters ( Motor Specifications) :
Rated Speed
3500 Rpm
Power Rating
40HP
Armature Rated Current
141 A
Armature Resistance
0.045Ω
Armature Voltage
230 V
Armature Inductance
0.73mH
Rotational Inertia (J)
0.156Kg.m2
Frictional Co-efficient (B)
0.015 N.m.s/rad
Maximum Gradient, G
0.06
Vehicle Specifications
Back Emf (Ea) = VT–IaRa = 230 – 141*.045 = 223.655 V
Rated torque (T) = P/Wb = 29840/366.52 = 81.414 N-m
Mass of the Vehicle
650 kg
Mass of one wheel
9 kg
Radius of the Tire®
.18m
Number of motors (n1)
1
Number of axels (n2)
2
Number of wheels
4
Number of motors
1
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Acceleration profile:
Presuming that the Vehicle is accelerating to the maximum speed of 80Km/hr. in 20 seconds, then
V−Vo
Acceleration (a)
=
𝑡
=
80 Km/hr
20𝑆𝑒𝑐
=
22.22
20
=
1.11 m/s2
Drive Cycle Definition:
The selected electric car is taken to a test drive from Guy Concordia metro to Atwater Metro.
Which is a 650m in length.This is a straight line so the vehicle is accelerated at starting point
with an acceleration of 1.11 m/s2.There will be a free run after it reaches is speed of 1.11 m/s and
then it will brake to stop and therefore there will be the deceleration speed. The drive cycle is
show below in the following graph.
Fig:1.1
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Speed distance curve- (Fig- 1.2)
Inertia (linear and Rotational)
Moment of Inertia Exerted on the wheel (J)
Load Inertia
Total Inertia
Inertia Referred to load side
Total Inertial referred to the load side
1
=
=
=
=
=
=
n*2*Mw* r2
4 * 0.5 * 9 * (0.18)2
0.5832 Kg.m2
m * r2
650 * (0.18)2
21.06 Kg.m2
=
=
=
=
=
Load inertia + Inertia due to wheel
18.62 + 0.392
21.64 Kg.m2
(1⁄3) ^2 * 21.64
2.4 Kg.m2
=
Inertia of the gear + Total inertia
Referred to load side
0.156 + 2.4
2.556 Kg.m2
=
=
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Torque Component
The Torque at the Motor Coupling Tm required to accelerate the vechice horizontally with the
acceleration of 1.08m/s2
Tm
=
m*a*r
=
650 * 1.11*0.18
=
129.87 N.m
Gradient Torque
The Gradient torque is Given by
TG
=
=
=
Gmgr
0.06* 650* 9.8* 0.18
68.80Nm
Rolling Torque
The Rolling Resistance of ordinary car tires on concrete lies between(0.01 to0.015).
The Rolling/Airgap Torque
Tr
=
=
The Torque exerted on the axle of the wheel Tw
=
=
Frictional torque
TF
=
=
=Cr * m * g * r
0.013*650*9.8*0.18
14.9Nm
𝐽∗𝑎
𝑟
0.5832∗1.11
0.18
= 3.5964 N.m
B*ω
0.015∗3500∗2𝜋
60
=5.5 N.m
The Total load torque required to accelerate the vehicle
TL
= Tm+ Tg+ Tr+ Tw + Tf
= 129.87 + 68.80 + 14.9+3.5964 +5.5
= 222.66 Nm
Gear Ratio:
=
=
𝐿𝑜𝑎𝑑 𝑇𝑜𝑟𝑞𝑢𝑒
𝑀𝑜𝑡𝑜𝑟 𝑇𝑜𝑟𝑞𝑢𝑒
222.66
81.414
= 2.73 ≈ 3
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Operating Envelope:
Speed Torque Curve of Motor
90
81.414
80
81.414
77.01
73.06
69.5
66.27
63.32
60.63
58.15
Torque (N/m)
70
60
50
40
30
20
10
0
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
Speed (RPM)
Fig1.3(a): Speed torque curve for motor
Speed Torque Curve of the vehicle
300
244.242
244.242
231.03
219.18
208.5
198.81
189.96
181.89
174.45
Torque (N/m)
200
100
0
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
-100
-174.45
-181.89
-189.96
-198.81
-208.5
-219.18
-231.03
-244.242
-200
-242.242
-300
Speed (RPM)
Fig 1.3 (b)
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Fig: Speed torque curve of the vehicle
Part-2
Component Specification
DC-DC Boost Converter:
We need a Boost converter after the battery to step up the voltage. The reason is that the battery
doesn’t provide enough voltage to fed the motor, Hence a Boost converter1 is used to boost the
voltage level. The converter is selected such that it works properly according to the specified
voltage and current ratings. 5 Volt is required to supply the controller, the buck converter is used
supply the power to the
converter from the auxiliary battery
Battery:
Batteries are used to supply the electrical power to drive the vehicle. Rechargeable batteries are
used in the electric vehicle. The Lithium ion Batteries2 are used owing to long life cycle and high
density
We have provide large amount of power supply as continuous basis. Thus we use a series
connection of battery for entire module as a battery bank
Rated current of the motor
= 141A
Converter efficiency from the data sheet
= 92%
Wiring efficiency
= 97%
Depth of discharge
= 80%
Battery efficiency
= 95%
Current rating at the controller
= 0.80∗0.92∗0.95∗0.97
141
= 207.9
Page | 8
Consider a 24V 180 Am of 7 such batteries are connected in series to increase the battery bank
output voltage to 120V. If we charge the battery fully, it will approximately operate for 48 minutes.
Auxiliary Battery:
In the vehicle there will be some auxiliary components, such as as the head lamp, indicator, horn,
auxiliary speaker etc. We need a separate sets of batteries a auxiliaries since these electronic
components require less lower. We might a buck converter to steup down the auxiliary voltage
while needed or we can directly use the voltage to the required equipments.
Motor Speed Controller:
It is as electronic microprocessor based circuit, where it is used to vary and control the flow of
power from the battery to the motor and hence the motor speed[4].
Fuse:
A Fuse is a type of low resistance resistor that acts as a sacrificial device to provide overcurrent
protection. A fuse interrupts an excessive current so that further damage by overheating or fire is
prevented. Usually 125% of the rated current value is selected as the fuse rating.
Description
Battery bank to the Converter
Ampere Rating
220-440
Manufacturer Details
CANADIAN FUSES
CLASS H
power converter to the motor
80-1120
Cooper Buss-man
Low-Peak™ 250V Class RK1
Auxiliary battery to components
1.5A
Little-fuse
ATO® Blade Fuse
Page | 9
Driver circuit:
A driver circuit is used to control the duty cycle of the boost converter. A Mosfet based driver
circuit is used in this case to enable smooth switching in the boost circuit. Some boost
converter modules are equipped with in- built driver circuits. The duty cycle can be fixed or varied
in order to suit the voltage requirement.
2. Cable size and length specification:
Three different types of wires are used in order to carry the power for different components.
Size
AWG
6
mm2
13.302
22
14
2.081
Diameter
(Inch)
Resistance Resistance Voltage Output Voltage
Percentage
@25○C
(V)
Loss(%)
for Length Drop
(Ohm/km) (Ohm)
(Volt)
0.1871
1.302
0.00238
0.4760
11.5240
3.976%
0.744
54
0.10800
7.884
222.116
3.428%
0.0740
8.450
.01521
0.30420 11.6958
2.535%
Table - Cable specification.
3. Sensors and transducers selection:
Speed Sensor:
This sensor will sense the motor speed and it will give the vehicle speed in terms of Mph/Kph on the
car dashboard. The Speed on the motor shaft needs to be fed to the Motor controller as a feedback
and for control operation. The 906 or 907 XP (explosion proof) Hall Effect sensors is used in this
vehicle. Here, The Input voltage (Vdc) is 4.5 to 25 volts. O/ P voltage is 0.4 - 0.6 volts.
Page | 10
Voltage Sensor:
This sensor will be used to connect the two batteries one is normal battery and other is emergency
battery. Whenever the voltage across the main battery falls below 65% this battery will be cut off
from the system and emergency battery will be providing the backup power.
Function
Range
Resolution
(Volts) voltage
rating
200V
0.1mV
2V
1mV
Accuracy
±(0.8% reading+3.5 digits)
Current Sensor:
Current sensor is used to detect electric current in a wire, and generates a signal proportional to
it. The generated signal is fed to the controller for control of the motor so that the motor can be
operated within the safety limits. Honey Well - DCT 500 to 1200A Large Aperture is used in this
vehicle. The Rated current is 25Amps. The response time is less than 0.2 µs. Operating temperature
range is between -40 °C to 85 °C.
Speed-meter:
It is used to measure and displays the instantaneous speed of a vehicle. At any point of time the
driver need to know the speed he is travelling as required by the local transport law. Hence the
Speedometer measures and displays the speed to the driver. VDO – 1323 is used in this vehicle
Page | 11
Gear Ratio:
It is the ratio of the Input speed to the Output Speed. Gear teeth are designed so that the number
of teeth on a gear is proportional to the radius of its pitch circle, and so that the pitch circles of
meshing gears roll on each other without slipping.
Gear Ratio:
𝐿𝑜𝑎𝑑 𝑇𝑜𝑟𝑞𝑢𝑒
= 𝑀𝑜𝑡𝑜𝑟 𝑇𝑜𝑟𝑞𝑢𝑒
222.66
= 81.414 = 2.73 ≈ 3
In the EV Vehicle, a straight-tooth spur gear is used because they are easier to manufacture and
can transmit high torque loads. The number of teeth on the gear is selected such that, the gear
ration is 3 Hence the number of teeth are selected based on the standard teeth ratios. The Number
of teeth in the driver gear is 12 and the Number of teeth in the Driven Gear is 36.
Schemetic Diagram:
Fig: 1.4 Schematic diagram
Page | 12
5. Wiring Diagram
A wiring diagram is a simplified conventional pictorial representation of an electrical circuit. It
shows the components of the circuit as simplified shapes, and the power and signal connections
between the devices. The Wiring diagram used for this electric vehicle is given below.
Fig : 1.5 Wiring Diagram
Parts List:
Table– Parts list used
Parts
Qty Manufacturer
Battery Bank -24V,180Ah
7
Lithium battery 24V 180Ah
DC-DC Converter160/230V
1
BRUSA BSC614-24V DC/DC Converter
DC-DC Converter –12/5 V
1
Murata Power Solutions -OKX-T/10-D12x-C
Motor Controller
1g
Speed Sensor
1
Battery Temperature Sensor
2
Page | 13
bgbcb
Cytron
5-25V
Single DC
Motor
906 or13A,
907 XP
(explosion
proof)
HallController
Effect sensors
Xantrex – TRUECharge2
Current Sensor
1
DCT 500 to 1200A Large Aperture
Speedometer
1
VDO -1323
Break relay
1
YU JIE - RC0-600-482
Head lamp, Tail Lamp
4
ANZO/H4
Horn
1
Wolo – 330
Fuse
3
Auxiliary Battery 12V/160Ah
1
Cooper Bussmann
Low-Peak™ 250V Class
POLINOVEL
- PL12-150
RK1
Controller Design:
The applied voltage amplitude controls the motor speed. The O/P speed is controlled by a speed
controller. Here, it is implemented as a conventional proportional-integral (PI) controller. We
calculated the boost converter transfer function by using below equation
Duty Cycle of the converter (D)
= Ton / Ts = (230-120)/ 230
= 0.478
If the efficiency is 97% then D
=
0.478
0.97
= 0.493
The Constant Kt
=
223.655
81.414
= 2.75
Required current to induce Ia
𝑇
=𝐾
=
81.414
0.61
= 29.60 A
Assume efficiency of the motor is
= 97%
So, the current Ia1
=
29.60
0.97
= 30.52A
Page | 14
Thus, inductance (L)
=
(230−120)(1−0.493)
30.52×8500
= 2.15*10-4 H or .215mH
Therefore, we can use 0.215mH inductor.
𝑉𝑜
𝑉𝑠
=
(1−𝐷)𝑉𝑜 −(𝐿𝐼𝑙 )𝑆
𝐿
𝑅
(𝐿𝐶)𝑆 2 + 𝑠+ (1−𝐷)2
Here, D=0.478
𝑉𝑜
So, 𝑉𝑠 =
(1−0.478)230−(.215𝑒−3∗141)𝑆
𝑇
222.66
KW = 𝑤 =366.52 = 0.61
..215𝑒−3
(.215𝑒−3∗.125)𝑆 2 +
𝑠+ (1−0.478)2
0.045
120.06−(6.7257𝑒−5)𝑆
= 5.96𝑒−8𝑆2 +1.06𝑒−5𝑠+ 0.272
Fig: 1.6- DC motor.
Now,
1
Transfer function1 = 0.156+0.015
Page | 15
1
Transfer function2 = .045+(0.73∗10−3 )𝑆
Simulation on Matlab Simulink:
Fig: 1.7 Simulation
Outputs:
Output Voltage waveform (Fig: 1.8)
1
6
Output current waveform (Fig: 1.9)
Output Speed waveform (Fig: 1.10)
1
7
Discussion:




The output voltage waveform tentatively shows that required output voltage is 230V. It got
stability after increasing exponentially.
From the current waveform we see it has started increasing rapidly and then it changes it
course. After that current waveform goes for stable situation for particular time period. Again
it went up rapidly and reached constancy at around 90A, which is not very close to the rated
current 141A. The current waveform doesn’t fully comply with the expected value
The speed curve looks fine as it started with exponential increase and exceeded the rated
speed and then it came back close to 3500 rpm.
I think I partially succeeded as well as partially failed with the project as my current rating
doesn’t really comply with the expected result, whereas the voltage and speed ratings look
just fine. Anyway, I learned a lot doing this project and it will be really useful in the future.
Conclusion:
The vehicle is designed approximately as per the given value. The torque required to drive the vehicle
is calculated. The required gear ratio is calculated carefully in order to accelerate the vehicle
smoothly. Then the drive cycle of the vehicle was designed and the torque curves are drawn based
on this torque speed curves are plotted. The electronic components and the controllers are selected
based on the motor rating and the current loop simulation of the vehicle is performed. Later we
design the corresponding wiring diagram, schematic diagram and select the battery bank. Before
that we select the rated component (e.g. capacitor, diode, IGBT switch) according to inductance
from the websiteFrom the simulation results we can conclude that the theoretical colocation are
almost similar to that obtained from the simulation. Hence the design of the desired electric vehicle
is somewhat successful.
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References:
1. http://www.metricmind.com/products/brusa-bsc614-24v/
2. https://www.victronenergy.com/batteries/lithium-battery24v-180ah
3. http://www.thomasnet.com/ccpcontent.html?ccpid=40784
4. http://www.robotshop.com/en/cytron-13a-5-30v-single-dcmotor-controller.html
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