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DEVELOPMENT OF CHARGING SYSTEM FOR ADVANCED
VEHICLE
RAYMOND JOSEPH
A report submitted in partial fulfillment
of the requirements for the award of the Degree of
Bachelor of Mechanical Engineering
Faculty of Mechanical Engineering
Universiti Malaysia Pahang
.-PERPUSTAKAAN
UNIVE1STI MALAYSIA PAHANG No. Paroehan No. Pacogflun
037844 TL - Tarikh
P2Juli2MAY 2008
ABSTRACT
Development of charging system for advanced vehicle becomes so
much important nowadays. Every manufacturer is competing against each
other to get the best design of the charging machine. In the development, the
optimum design of the rotor and the control were considered. Most alternators
for the charging system nowadays already upgraded into Integrated Alternator
Starter, which combining the starter motor and alternator. This configuration
has the best yield and after further researches, the technology has been
implemented to manufacture better engines such as the hybrid engine. The
technology is actually to improve the electric ability of most vehicles. Since
the charging system was improved, the battery capacity was also expanded to
store more power. Furthermore, hybrid vehicle can be more reliable same as
the conventional vehicle which uses fuel as their main vitality.
ABSTRAK
Kemajuan dalam sistem pengecasan untuk kenderaan moden menjadi
sangat penting ketika i. Setiap pengilang dan pembuat saling berlumba untuk
mendapatkan rekabentuk yang terbaik bagi sistem pengecasan kenderaan.
Dalam usaha itu, rekabentuk untuk rotor dan kawalan motor adalah
dititikberatkan. Kebanyakan alternator untuic sistem pengecasan path hari liii
telah ditambah nilai kepada Integrated Alternator Starter iaitu gabungan
motor penghidup dan alternator. Konfigurasi mi mempunyai had yang terbaik
dan selepas kajian yang lebihjauh dijalankan, teknologi mi diguna pakai untuk
pembuatan enjin yang lebih baik seperti enjin hibrid. Teknologi seperti ml
sebenamya adalah untuk menambahbaik keupayaan elektrik untuk banyak
kenderaan. Oleh kerana sistem pengecasan telah ditambah balk, kapasiti bateri
juga boleh ditambah untuk menyimpan lebih tenaga. Lebih-lebih lagi,
kenderaan hibrid boleh diharapkan sama seperti kenderaan konvensional yang
menggunakan minyak sebagai bahan utama.
vi
vii
TABLE OF CONTENTS
TITLE PAGE
STUDENT DECLARATION I'
DEDICATION In
ACKNOWLEDGEMENT
iv
ABSTRACT V
ABSTRAK vi
TABLE OF CONTENT 'Tn
LIST OF TABLE In
LIST OF FIGURE XII'
LIST OF SYMBOLS xiv
viii
CHAPTER TITLE
1
INTRODUCTION
1.1 Background
1.2 Problem Statement
1.3 Objective of the project
1.4 Project Scopes
2
LITERATURE REVIEW
2.1 Introduction
2.1.1 Starting
2.1.2 Starting Alternator Criteria
2.1.3 Conventional Starter motors and circuit
2.1.4 Principal of Operation
2.1.5 DC motor characteristics
2.1.6 Permanent Magnet Starters
2.2 Charging System
2.2.1 Overview
2.2.2 Charging System Principles
2.2.2.1 Basic Principles
2.2.2.2 Vehicle Electric Loads
2.2.2.3 Charging Voltages
2.3 Alternator Principles
2.3.1 Rotor
2.3.2 Stator
2.3.2.1 Star Wound
2.3.2.2 Delta Wound
2.3.3 Calculation of Frequency
2.4 Permanent Magnet Machines
2.5 Trapezoidal PMAC
PAGE
1
2
2
2
3
3
7
7
8
8
10
11
11
12
12
12
12
13
14
14
15
16
17
17
18
ix
2.6 Sinusoidal PMAC 18
2.6.2 Rotor Type for Sinusoidal PMAC 20
2.6.2.1 Surface Mounted PM Type 20
2.6.2.2 Interior Permanent Magnet 21
2.6.2.3 Unique interior Permanent Magnet 22
2.7 Coil Pitch 24
2.7.1 Full Pitch Winding 24
2.7.2 Fractional Pitch Winding 25
2.7.3 Calculating Pitch Factor 26
2.7.4 Minimizing Harmonic Content 26
2.8 Reduction of Cogging Torque 27
2.8.1 Cogging Torque 27
2.8.2 Optimum Ratio of Pole-arc to Pole-pitch 27
2.9 Summary 28
3
METHODOLOGY
3.1 Overview 29
3.2 Project Methodology 29
3.3 Combining the Alternator and Starter system 30
3.4 The Suggested Method 30
3.4.1 Rotor Selection 31
3.4.2 Magnet Selection 32
3.4.3 Stator Selection 33
3.5 The New Design of Interior Permanent Magnet Motor 34
3.6 Theoretical Estimation 36
4 RESULT AND DISCUSSION
4.1 introduction 40
4.2 Result 41
4.3 Discussion 41
4.4 Summary 42
REFERENCES
APPENDICES
APPENDIX A Details of design drawing APPENDIX B The theoretical calculation APPENDIX C Technical Paper
xi
LIST OF TABLE
TABLE NO. TITLE PAGE
2.1 Description of motor 9 2.2 Comparison of machines 19 2.3 Comparison of rotor 23 4.1 Result on data and operating characteristic 41
xli
LIST OF FIGURE
FIGURE NO. TITLE PAGE
2.1 Motoring Characteristics 4
2.2 Conventional Engine System 5
2.3 Integrated Alternator Starter 6
2.4 Basic Circuit for starting system 7
2.5 DC Motor Characteristics 8
2.6 Principle of a three-phase alternator 13
2.7 Rotor 14
2.8 A) Stator B) Real stator 14
2.9 Star-Wound 15
2.10 Delta-wound 16
2.11 Rotor of Surface Mounted motor 20
2.12 Rotor of Interior Permanent Magnet 21
2.13 Rotor with Unique Configuration 22
2.14 Full Pitch 24
2.15 Fractional Pitch 25
2.16 Definition of pole-arc to pole pitch 27
2.17 The Selected Machine 28
3.1 Suggestion Method 30
3.2 Interior Permanent Magnet Rotor 31
3.3 Pole-arc, pole-pitch and coil span 32
3.4 Stator with 5/6 pitch coil configuration 33
3.5 The 2D view of the New IPM 34
3.6 The 3D view of the New IPM 34
3.7 The exploded view of the new design. 35
xlii
LIST OF SYMBOLS
Vag Air gap permeance
Op Angular width,of pole pitch
P0 Magnetic constant
/ Active length
Ld Direct-axis Inductance
Lq Quadrature-axis Inductance
1d Direct-axis current
1q Quadrature-axis Inductance
Xd Direct-axis Per-unit Reactance
xq Quadrature-axis Per-unit Reactance
xiv
CHAPTER 1
INTRODUCTION
1.1 Background
Most manufacturers are making incremental improvements to existing
technology. However, electronic control continues to be used in more areas of
the vehicle. The main 'step change' in the near future will be the move to 42 V
systems, which opens the door for other developments. Development of the
Charging System for Advanced Vehicle is a process of producing new
charging system for the advanced vehicle including electric and hybrid cars.
This includes any transportation units that are wheeling on the road such as
cars, trucks, buses and motorcycles. Modem transportation units nowadays
require a better charging system so that they will work enhanced.
1.2 Problem statement
The need to improve the starting and charging system seems to
increase nowadays because higher efficiency of these systems will reduce
emission, reduce fuel consumption and adding ability to vehicle to bear higher
loads. If the emission is reduce, the rate of pollution caused by vehicles will
drop as well as peoples health. The major issue of fuel pricing will also drop
because people are less depending to the fuel anymore. Thus, combining the
starter and alternator will reduce the components in the engine in addition to
reduce the complexity and weight of the whole engine system.
1.3 Objective of the project
1. To combine the starter and alternator for advance vehicle.
2. To extract the output data for the new design of Integrated
Alternator Starter.
1.4 Project scopes
1. To understand the work of alternator and the starter motor.
2. To select the type of Alternator Starter machine for this project.
3. To design the Alternator Starter rotor and stator.
CHAPTER 2
LITERATURE REVIEW
2.1 Introduction
2.1.1 Starting
An internal combustion engine has to fulfill criteria such as the
combustible mixture, compression stroke, form of ignition and the minimum
starting speed (about 100 rev/mm) in order to start and continue running. In
order to attain these, the minimum starting speed must be achieved. The ability
to reach this minimum speed is again dependant on a numbers of factors.
• Rated voltage of the starting system
• Lowest possible temperature at which it must still be possible to start
the engine. This is known as the starting limit temperature.
• Engine cranking resistance. In other words the torque required to
crank the engine at its starting limit temperature (including the initial
stalled torque).
• Battery characteristics
• Voltage drop between the battery and the starter.
• Minimum cranking speed of the engine at the starting limit
temperature.
4
The typical starter motor can possibly be viewed as an isolated
component within the vehicle electrical system. The battery in particular is of
prime importance.
Another particularly important consideration in relation to engine
starting requirements is the starting requirement is the starting limit
temperature. Figure shows how, as temperature decreases, starter torque also
decreases and the torque required cranking the engine to its minimum speed
increases.
Typical starting limit temperatures are - 180C to -250C for passenger
cars and -150C to -20°C for trucks and buses. Figures from starter
manufacturers are normally quoted at both +20 0C and -200C.
ST = Starter torque ET Engft torque
(crankinZ = Crsnkng speed
21M 201C 240 20T ST
ET
C
Cs
Cs
so too
Figure 2.1: Motoring Characteristic [25]
Starter: Cranking (80-200 rpm)
Engine: Accelerating up to the idle speed (500 - 800 rpm)
I Belt driven I
Alternator/Generator: Battery: Generate electric power , Charging / starting from idle range to redline of 3500 to 6500 rpm
Figure 2.2: Conventional Engine System
The conventional engine system can be simplified to Figure 2.2. It can
be identified that the system used starter and alternator as different
component.
5
Starter Alternator: Battery: Cranking (80-200 rpm) 4 Starting/charging Generate electric power from idle range to redline of 3500 to 6500 rpm.
Belt driven
Engine: Accelerating up to idle speed (500 - 800rpm)
Figure 2.3 : Integrated Alternator Starter
In this project, to make sure the objective of combining the alternator
and starter is achieved, the basic design of the engine system will be slightly
modified. The proposed design for the Starter Alternator in the engine system
is shown in the Figure 2.3.
7
2.1.2 Starter Alternator criteria
The criteria for this machine are that it has the ability of a starter and
the ability of an alternator. The machine is belt driven and connected to the
engine crankshaft same as the default conventional alternator. The next
explanation will mention both the conventional type of starter and alternator
used in the automotive these days. Considering the strength and weaknesses
of different motors and alternators, this project could carry out the best type
of starter will combine with the best type of alternator and will be renamed as
Starter Alternator.
2.1.3 Conventional Starter motors and circuit
In comparison with most other circuits on the modem vehicle, the
starter circuit is very simple. The problem to be overcome, however, is that of
volt drop in the main supply wires. The starter is usually operated by a spring-
loaded key switch, and the same switch also controls the ignition and
accessories. The supply from the key switch, via a relay in many cases, causes
the starter solenoid to operate, and this in turn, by as set of contacts, controls
the heavy current. In some cases an extra terminal on the starter solenoid
provides an output when cranking, which is usually used to bypass a dropping
resistor on the ignition or fuel pump circuits. The basic circuit for starting
system is shown in Figure 2.4
HeaTT CLUTent Utre
l; - - . Solenoid Svcitth
E4 fflery
L
Figure 2.4 : Basic Circuit for starting system
8
2.1.4 Principle of operation
The simple definition of any motor is a machine to convert electrical
energy into mechanical energy. The starter motor is no exception. When
current flows through a conductor placed in a magnetic field, a force is
created acting on the conductor relative to the field. The magnitude of this
force is proportional to the field strength, the length of the conductor in the
field and the current flowing in the conductor.
A conventional starter must also have some method of engaging with,
and release from, the vehicle's flywheel ring gear. In the case of light vehicle
starters, this is achieved either by an inertia-type engagement or a pre-
engagement method. But in the development of combined starter alternator,
this operation will not be employed because the machine will never released
from the main engine crankshaft through the belt.
2.1.5 DC motor characteristics
^hunt wound motor Permanent
magnet motor
Compound wound motor
Series wound
I I
Figure 2.5: DC Motor Characteristics [25]
Name Diagram Description
Shunt • Field winding is connected
wound in parallel with the
motor armature
Due to the constant
excitation of the fields, the
speed of this motor
remains constant, virtually
-
independent of torque
Permanent • The excitation will remain
magnet constant under all motor operating conditions.
jt4 ] Representation of • Smaller and less weight - permanent magnet
fields
Compound • Combination of shunt and
wound,lcrnc shunt
eries field series wound motor.
motor windings S}1OXt thwt - - -
• Characteristics can vary
depending on how the field hunt f3eld win din windings are connected.
Series • The armature current wound seriesfield passes through the fields motor making it necessary for the
windings to consist usually
of only a few turns of
- heavy wire.
• When start under load the
high initial current,
generates a very strong
initial torque.
Table 2.1: Descriptions of Motor [251
10
2.1.6 Permanent Magnet Starters
The two main advantages of these motors, compared to the
conventional types, are less weight and smaller size. This makes the
permanent magnet starter a popular choice by vehicle manufacturers as, due
to the lower lines of today's car, less space is now available for engine
electrical system. The reduction in weight provides a contribution towards
reducing fuel consumption.
The principle of operation is similar in most respects to the
conventional pre-engaged starter motor. The reduction in weight is in the
region of 15% and the diameter of the yoke can be reduced by a similar
factor.
Permanent magnet provides constant excitation and it would be
reasonable to expect the speed and torque characteristic to be constant.
However, due to the fall in battery voltage under load and the low resistance
of the armature windings, the characteristic is comparable to series wound
motors. In some cases, fluxes concentrating pieces or interpoles are used
between the main magnets. Due to the warping effect of the magnetic field,
this tends to make the characteristic curve very similar to that of the series
motor.
2.2 CHARGING SYSTEM
2.2.1 Overview
The current demands made by modem vehicles are considerable. The
charging system must be able to meet these demands under all operating
conditions and still 'fast charge' the battery.
The main component of the charging system is the alternator and on
most modem vehicles - with the exception of its associated wiring - this is the
only component in the charging system.
The charging system must meet the following criteria (when the engine is
running)
1. Supply the current demands made by all loads
2. Supply whatever charge the battery demands
3. Operate at idle speed
4. Supply constant voltage under all conditions
5. Have an efficient power- to- weight ratio
6. Be reliable, quiet, and have resistance to contamination
7. Require low maintenance
8. Provide an indication of correct operation
11
12
2.2.2 Charging system principles
2.2.2.1 Basic principles
The basic vehicle charging systems are containing three sections, the
alternator, battery, and vehicle loads. When the alternator voltage is less than
the battery (engine slow or not running for example), the direction of the
current flow is from the battery to the vehicles loads. The alternator diodes
prevent current flowing into the alternator. When the alternator output is
greater than the battery voltage, current will flow from the alternator to the
vehicle loads and the battery.
2.2.2.2 Vehicle electrical loads
The loads placed on an alternator can be considered as falling under
three separate headings: continuous, prolonged and intermittent. The charging
system of a modern vehicle has to cope with demands under many varied
conditions. To give some indication as to the output that may be required,
consider the power used by each individual component and add this total to
the power required to change the battery.
2.2.2.3 Charging voltages
The main consideration for the charging voltage is the battery terminal
voltage when fully charged. If the charging system voltage is set to this value
then there can be no risk of overcharging the battery. This is known as the
constant voltage charging technique.
2.3 ALTERNATOR PRINCIPLES
Figure 2.6 Principle of a three-phase alternator
Figure 2.6 shows the basic principle of a three-phase alternator.
Electromagnetic induction is caused by rotating magnet inside a stationary
loop or loops of wire. In a practical alternator, the rotating magnet is an
electromagnet that supplied via two slip rings.
13