24
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 P2Juli2 MAY 2008

DEVELOPMENT OF CHARGING SYSTEM FOR ADVANCED VEHICLE RAYMOND JOSEPH

  • Upload
    others

  • View
    2

  • Download
    0

Embed Size (px)

Citation preview

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

CONCLUSION AND RECOMMENDATION

5.1 Conclusion

43

5.2 Recommendation

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