main project.ppt1

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A NOVEL THREE PHASE TO FIVE PHASE TRANSFORMATION USING SPECIAL

TRANSFORMER CONNECTIONS

CHAPTER 1

INTRODUCTION

of research recently due to th

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1. INTRODUCTION

Multiphase (more than three phase) systems are the

focus eir inherent advantages compared to their three-phase

counterparts applicability of multiphase systems is

explored in electric power generation, transmission, and

utilization. The research on six-phase transmission system

was initiated due to the rising cost of right of way for

transmission corridors, environmental issues, and various

stringent licensing laws. Six-phase transmission lines can

provide the same power capacity with a lower phase-to-

phase voltage and smaller, more compact towers compared

to a standard double-circuit three-phase line.

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As far as multiphase motor drives are concerned, the

first proposal was given by Ward and Harrer way back in

1969. The focus of research on multiphase electric drive is

limited to the modeling and control of the supply systems

Little effort is made to develop any static transformation

system to change the phase number from three to n phase

(where n=3 and odd). The scenario has now changed

proposing a novel phase transformation system which

converts an available three-phase supply to an output five-

phase supply.

Multiphase, especially a 6-phase and 12-phase system

is found to produce less ripple with a higher frequency of

ripple in an acdc rectifier system. Thus 6 and 12-phase

transformers are designed to feed a multi-pulse rectifier

system and the technology has matured. Recently 24-phase

and 36-phase transformer systems have been proposed for

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supplying a multi-pulse rectifier system]. The reason of

choice for a 6, 12, or 24-phase system is that these numbers

are multiples of three and designing this type of system is

simple and straightforward. However increase in the

number of phases certainly enhances the complexity of the

system. None of these designs are available for an odd

number of phases, such as 5, 7, 11, etc.

Normally a no-load test, blocked rotor, and load tests

are performed on a motor to determine its parameters.

Although the supply used for a multiphase motor drive

obtained from a multiphase inverter could have more

current ripple, there are control methods available to lower

the current distortion even below 1%, based on application

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and requirement. Hence, the machine parameters obtained

by using the pulse width-modulated (PWM) supply may

not provide the precise true value. Thus, a pure sinusoidal

supply system available from the utility grid is required to

feed the motor. This paper proposes a special transformer

connection scheme to obtain a balanced five-phase supply

with the input as balanced three phases.

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CHAPTER 2

BLOCK DIAGRAM

.

2. BLOCK DIAGRAM

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The block diagram of the proposed system is shown in

Fig. The fixed voltage and fixed frequency available grid

supply can be transformed to the fixed voltage and fixed

frequency five-phase output supply. The output however

may be made variable by inserting the autotransformer at

the input side.

Fig.2 (a) Block representation of the proposed system

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Fig 2(b) block diagram

.

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CHAPTER 3

WINDING ARRANGEMENT OF FIVE PHASE

STAR OUTPUT



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3. WINDING ARRANGEMENT OF FIVE PHASE

STAR OUTPUT

The input and output supply can be arranged in the

following manner:

1) input star, output star;

2) input star, output polygon;

3) input delta, output star;

4) Input delta, output polygon.

Since input is a three-phase system, the windings are

connected in a usual fashion. The output/secondary side

connection is discussed in the following subsections.



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Three separate cores are designed with each

carrying one primary and three secondary coils, except in

one core where only two secondary coils are used. Six

terminals of primaries are connected in an appropriate

manner resulting in star and/or delta connections and the 16

terminals of secondaries are connected in a different

fashion resulting in star or polygon output. The connection

scheme of secondary windings to obtain a star output is

illustrated in Fig. and the corresponding phasordiagram is

illustrated in Fig3 (a)



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The proposed transformer winding connections and

phasor diagram of proposed transformer connections as

shown below in fig 3(a), 3(b)&3(c)



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Fig 3(a) proposed transformer winding

connection



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Fig 3(b) Proposed transformer winding connection (star).



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Fig. 3(c) Phasor diagram of the proposed transformer

connection (star-star).

3.1 constructional details of winding arrangement:

The construction of output phases with requisite phase

angles of 72 between each phase is obtained using

appropriate turn ratios, and the governing phasor equations

are illustrated below. The turn ratios are different in each

phase. The choice of turn ratio is the key in creating the

requisite phase displacement in the output phases. The

input phases are designated with letters X Y, and Z

and the output are designated with letters A, B, C,



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D, and E. As illustrated in Fig., the output phase A is

along the input phase X. The output phase B results

from the phasor sum of winding voltage c6c5 and

b1b2, the output phase C is obtained by the phasor sum

of winding voltages a3a4 and b3b4. The output phase

D is obtained by the phasor addition of winding voltages

a3a4 and c1c2 and similarly output phase E results

from the phasor sum of the winding voltages c3c4 and

b6b5 . In this way, five phases are obtained. The

transformation from three to five and vice-versa is further

obtained by using the relation given below



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CHAPTER 4

THREE-PHASE ELECTRIC POWER

4. THREE-PHASE ELECTRIC POWER



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4.1 Introduction to three phase electric power:

Three-phase electric power is a common method

ofalternating current electric power transmission. It is a

type ofpoly-phase system and is the most common method

used by electric power distribution grids worldwide to

distribute power. It is also used to power large motors and

other large loads. A three-phase system is generally moreeconomical than others because it uses less conductor

material to transmit electric power.

In a three-phase system, three circuit conductors carry

three alternating currents (of the same frequency) which

reach their instantaneous peak values at different times.

Taking one conductor as the reference, the other two

currents are delayed in time by one-third and two-thirds of

one cycle of the electric current. The delay between phases

has the effect of giving constant power transfer over each

http://en.wikipedia.org/wiki/Alternating-current_electric_powerhttp://en.wikipedia.org/wiki/Electric_powerhttp://en.wikipedia.org/wiki/Polyphase_systemhttp://en.wikipedia.org/wiki/Electric_power_distribution_gridhttp://en.wikipedia.org/wiki/Electric_motorhttp://en.wikipedia.org/wiki/Three-phasehttp://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Electric_powerhttp://en.wikipedia.org/wiki/Polyphase_systemhttp://en.wikipedia.org/wiki/Electric_power_distribution_gridhttp://en.wikipedia.org/wiki/Electric_motorhttp://en.wikipedia.org/wiki/Three-phasehttp://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Alternating-current_electric_power


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cycle of the current and also makes it possible to produce a

rotating magnetic field in an electric motor.

Three-phase systems may have a neutral wire. A

neutral wire allows the three-phase system to use a higher

voltage while still supporting lower-voltage single-

phase appliances. In high-voltage distribution situations, it

is common not to have a neutral wire as the loads can

simply be connected between phases (phase-phase

connection).

4.2 properties of three phase electric power:

http://en.wikipedia.org/wiki/Electric_motorhttp://en.wikipedia.org/wiki/Ground_and_neutralhttp://en.wikipedia.org/wiki/Single-phase_electric_powerhttp://en.wikipedia.org/wiki/Single-phase_electric_powerhttp://en.wikipedia.org/wiki/Electric_motorhttp://en.wikipedia.org/wiki/Ground_and_neutralhttp://en.wikipedia.org/wiki/Single-phase_electric_powerhttp://en.wikipedia.org/wiki/Single-phase_electric_power


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Three-phase has properties that make it very desirable in

electric power systems:

The phase currents tend to cancel out one another,

summing to zero in the case of a linear balanced

load. This makes it possible to eliminate or reduce

the size of the neutral conductor; all the phase

conductors carry the same current and so can be the

same size, for a balanced load.

Power transfer into a linear balanced load is

constant, which helps to reduce generator and motor

vibrations. Three-phase systems can produce a magnetic field

that rotates in a specified direction, which simplifies

the design of electric motors.



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CHAPTER 5

TURNS RATIO

5. TURNS RATIO



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5.1 Turns ratio:

Transformers are used in a wide array of electrical or

electronic applications, providing functions that range from

isolation and stepping up or stepping down voltage and

current to noise rejection, signal measurement, regulation

and a host of functions particular to specific applications.

In order to test that a transformer will meet its design

specification, a number of functions should be tested and

one of the most commonly used tests is turns ratio.

5.2 Basic theory on turns ratio:

The turns ratio of a transformer is defined as the

number of turns on its secondary divided by the number of

turns on its primary. The voltage ratio of an ideal

transformer is directly related to the turns ratio.

( 1)



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The current ratio of an ideal transformer is inversely related

to the turns ratio:

(2)

Where

Vs = secondary voltage, Is = secondary current, Vp =primary voltage, Ip = primary current,

Ns = number of turns in the secondary winding and Np =

number of turns in the primary winding.

The turn ratio of a transformer therefore defines the

transformer as step-up or step-.down.

Step up transformer:



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A step-up transformer is one whose secondary voltage

is greater than its primary voltage and a transformer that

steps up voltage will step-down current.

Step down transformer:

A step-down transformer is one whose secondary

voltage is lower than its primary voltage and a transformer

that steps down voltage will step-up current.

5.3Voltage current turns ratio:



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5.4 Factors Affecting Turns Ratio Measurements:

In ideal transformer, the ratio of the physical turns

on any winding could be established simply by measuring

the rms output voltage on one winding, while applying a

known rms input voltage of an appropriate frequency to

another winding. Under these conditions, the ratio of the

input to output voltages would be equal to the physical

turns ratio of these windings.

In real transformers a number of electrical

properties that result in a voltage or current ratio that may

be not equal to the physical turns ratio. The following

schematic diagram illustrates the electrical properties of a

real transformer, with the ideal transformer component

shown in the center, plus the electrical components thatrepresent various additional properties of the transformer.



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Fig 5(e) winding connections of real transformer

5.5 Electric properties of real transformer:

L1, L2 and L3 represent the primary and secondary

leakage inductance caused by incomplete magnetic

coupling between the windings.

R1, R2 and R3 represent the resistance (or copper loss)

of the primary and secondary windings. C1, C2, and C3 represent the interwinding

capacitance.



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Lp represents the magnetizing inductance core loss.

Rc represents the core loss of which three areas

contribute, eddy current loss (increases with

frequency), hysteresis loss (increases with flux

density) and residual loss (partially due to resonance).

CHAPTER 6



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FIVE-PHASE SYSTEM

6. FIVE-PHASE SYSTEM

Variable speed electric drives predominately utilise

three-phase machines. Since multi-phase machines offersome inherent advantages over three-phase counterpart.

Major advantages of using a multi-phase machine instead

of a three-phase machine are:



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i. Higher torque density

ii. Greater efficiency.

iii. Reduced torque pulsations.

iv. greater fault tolerance

v. reduction in the required rating per inverter leg

.

Noise characteristics of multi-phase drives are better

when compared three-phase drive. Higher Phase number

yield smoother torque due to the simultaneous increase of

the frequency of the torque pulsation and reduction of the

torque ripple magnitude. Higher torque density in a multi-

phase machine is possible because fundamental spatial

field harmonic and space harmonic fields can be used to

enhance total torque. This advantage of enhanced torque

production stems that vector control of the machines fluxand torque produced by the interaction of the fundamental

field component and the fundamental stator current



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component requires only two stator currents (d-q current

components).

In a multi-phase machine, with at least five phases or

more, there are additional degrees of freedom, which can

be utilised to enhance the torque production through

injection of higher order current harmonics. The stability

analysis of five-phase drive system for harmonic injection

scheme is carried for both concentrated winding and

distributed winding machines.

6.1 Applications of five phase system:

i. Ship propulsion.



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ii. Traction, electric vehicles and in safety critical

applications requiring high degree of redundancy.

iii. water pumping in remote

iv. Weak grid locations where the power quality is not

adequate for operating sophisticated microprocessor

based controllers.

6.2 Need of five phase system:

The question arises why five-phase drive is at all

required not conventional three-phase drive. Five phase

drive has fault tolerant characteristic, reliable and higher

efficiency compared to three-phase drive. The power

electronic converters supplying multi-phase drives are

controlled using advanced digital signal processors (DSP)

and Field programmable Gate Arrays (FPGA).

6.3 Five phase drive structure:



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A simple open-loop five-phase drive structure is

elaborated in Fig6(a). The dc link voltage is adjusted from

the controlled rectifier by varying the conduction angles of

the thyristors. The frequency of the fundamental output is

controlled from the IGBT based voltage source inverter.

The inverter is operating in the quasi square wave mode

instead of more complex PWM mode. Thus the overall

control scheme is similar to a three-phase drive system.

Since the inverter is operating in square wave mode the

analogue circuit based controller is much simpler and

cheaper compared to more sophisticated digital signal

processor based control schemes. This type of solution is

very cheap and convenient for use in coarse applications

such as water pumping.The power quality of the remote

locations in developing countries such as Indian

subcontinents are not adequate for reliable and durableoperation of sensitive

microprocessors/microcontrollers/digital signal processors

based controllers.



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Fig 6(a) structure of five phase

drive

6.4 Three phase drive:

The predominant harmonics in a three-phase

induction motor drive are 5th and 7th, with 5th being

backward rotating and 7th being forward rotating both



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leading to 6th harmonic pulsating torques. The expression

for the sixth harmonic pulsating torque is given as;

Eqn 1(a)

An expression is derived for the sixth harmonic pulsating

torque in terms of fundamental voltage and equivalent

circuit parameter and is obtained as:

Eqn1(b)

Where

and y mk is the peak of kth harmonic

mutual flux,

V1 is the fundamental applied voltage, Xeq is the

equivalent leakage reactance and P is the number of poles

of induction machine.



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Where

Thus the ratio of pulsating torques for a typical motor in

two conduction modes is obtained as;

The relations show there is reduction in torque

ripples in five phase motor at 144 conduction mode by



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10% (approx) when compared with 180 conduction mode

of five phase motor, 700% when compared with 180

conduction modes of five phase motors, and 778% when

compared with 180 conduction mode of three phase motor

and 144 conduction mode of five phase motor.

6.6 Comparison of output performance on 5&6 phase

machine:

To provide basis for comparing the output current of

the 3, 5, and 6-phase machines, it is convenient to represent

the coupling of the rotor to stator windings through back-

emf.



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Fig 6(b) Five phase

machine

In general, winding harmonics coupled with

permeance harmonics due to stator slots and rotor saliency

lead to a back-emf with significant harmonic content.

Although important for evaluating acoustic noise, to

compare the output of the machined rectifiers it is

convenient to neglect harmonics and assume each of the

machines has a phase-o back-emf of the form

Where the amplitude e is a function of field flux linkage

and rotor speed.

6.7 Operation of 5&6 phase:

As conduction begins, the switching of each of the

rectifiers is a function of the back-emf waveforms and is

consistent with the numbering of the diodes. If one



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assumes equal back-emf amplitudes for the three machines,

the speed where conduction begins (the line-to line emf

exceeds the battery voltage) is lower for the 5-phase

machine. The 6-phase machine is constructed as two 3-

phase machines offset by 30 electrical degrees. Therefore,

the line-line emf of the 3 &6 phase machines is found from

the vector sum of two phases displaced by I20 degrees,

which is equal to . The line-line emf of the 5-phase

machine, in contrast is found the vector sum of two phases

displaced by 144 degrees, which is equal to 1.902ee. Thus,

for a given speed, one would expect a line-to-line emf that

is roughly 10% higher for the 5-phase machine compared

to the 3- and 6-phase machines. For a given number of

rotor poles and stator slot/pole/phase, 5-phase and 6-phase

machines will have 513 and twice the number of slots as

the. Carter's coefficient provides a starting point. For thegeometry studied, the resultant Carter coefficients are

shown in Table.



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Table: Carters coefficients for 3, 5 and 6 phase machines

These values were calculated assuming similar

slot openings and stator inner diameters for each of the

designs. Comparing values, the impact of the additional

slots is clear; the flux linkage for the 5 and 6-phasemachines will be reduced compared to the 3-phase

machine.

As the rotor speed increases above cut-in, the effect of

the source inductance is significant. To illustrate, the

modes of the 5-phase machine converter with a battery load

are shown in Fig5 (d).



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Fig 6 (c).

Operational modes of 5-phase machine

6.8 Modes of operation of 5&6 phase machines:

From the fig5 (d) it can be seen that between

rotor speeds of 1060-6000 rpm there are 8 distinct

conduction patterns of the rectifier. At speeds between

1060 and 1076 rpm, a sequence of 0-2 diodes are

conducting (mode 1): at speeds between 1076 and 1079



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rpm a sequence of 0-2-3-2 diodes are conducting (mode 2).

These modes are not shown due to their short durations. As

the rotor speed increases more diodes conduct and above

2563 rpm 5 diodes are always conducting.

To model the 5 and 6-phase machines, the back-emf

and magnetizing inductance obtained from the model of the

3- phase machine at each operating point are used.

Specifically, the values from the 3-phase machine are

multiplied by the ratio of Carter's coefficient of the 3-phase

machine to that of the 5and 6-phase machine to generate

the respective 5and 6-phase machine parameters. The stator

leakage inductance for each machine is calculated from the

respective slot geometry. The purpose of using the 3-phase

data to generate 5 and 6-phase machine parameters is to

assess the accuracy of using the ratio of Caner's coefficientto compare the performance of the three machines. The

simulated performance of the simplified machine models

are shown in Fig 6(d).



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Fig.6 (d) Simulated response using simplified machine

models

6.9 Comparison of cost:

In comparing the 5 and 6-phase machines, the 5-phase

concept offers some advantages in terms of product

performance as well as manufacturability that translate to

lower cost. For one, the 5-phase is comprised of fewer

slots. This helps not only the cost but also the machine

performance. A 5-phase machine, wound with one

slot/poly phase requires five stator slots per pole whereas a



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6-phase machine with one slot/pole/phase requires six slots

per pole. The added slots of the 6-phase also present

possible performance drawbacks. The flux will drop as a

result of the larger effective air gap. An additional concern

of the added slot count is the increase in eddy current

losses on the unlaminanted rotor pole pieces. If a

continuous assortment of diode current ratings were

available, one could select a diode for the 6-phase with

5/6th the current rating of the 5-phase generator.



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CHAPTER 7

MATLAB



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7. MATLAB

Mat lab is a high-performance language for

technical computing. It integrates computation,

visualization, and programming in an easy-to-use

environment where problems and solutions are expressed

in familiar mathematical notation. Typical uses include

Math and computation Algorithm development Data

acquisition Modeling, simulation, and prototyping Data



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analysis, exploration, and visualization Scientific and

engineering graphics Application development, including

graphical user interface building.

Matlab is an interactive system whose basic data

element is an array that does not require dimensioning.

This allows you to solve many technical computing

problems, especially those with matrix and vector

formulations, in a fraction of the time it would take to write

a program in a scalar no interactive language such as C or

FORTRAN.

The name matlab stands for matrix laboratory.

Matlab was originally written to provide easy access to

matrix software developed by the linpack and eispackprojects. Today, matlab engines incorporate the lapack and



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blas libraries, embedding the state of the art in software for

matrix computation.

Matlab features a family of add-on application-specific

solutions called toolboxes. Very important to most users of

matlab, toolboxes allow you to learn and apply specialized

technology. Toolboxes are comprehensive collections of

matlab functions (M-files) that extend the matlab

environment to solve particular classes of problems. Areas

in which toolboxes are available include signal processing,

control systems, neural networks, fuzzy logic, wavelets,simulation, and many others.

7.1 Main parts in mat lab:

The matlab system consists of five main parts:

Development Environment: This is the set of tools

and facilities that help you use matlab functions and files.

Many of these tools are graphical user interfaces. It



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includes the matlab desktop and Command Window, a

command history, an editor and debugger, and browsers for

viewing help, the workspace, files, and the search path.

Matlab Mathematical Function Library: This is a

vast collection of computational algorithms ranging from

elementary functions, like sum, sine, cosine, and complex

arithmetic, to more sophisticated functions like matrix

inverse, matrix eigenvalues, Bessel functions, and fast

Fourier transforms.

Matlab Language: This is a high-level

matrix/array language with control flow statements,

functions, data structures, input/output, and object-oriented

programming features. It allows both "programming in thesmall" to rapidly create quick and dirty throw-away



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programs, and "programming in the large" to create large

and complex application programs.

Matlab has extensive facilities for displaying vectors

and matrices as graphs, as well as annotating and printing

these graphs. It includes high-level functions for two-

dimensional and three-dimensional data visualization,

image processing, animation, and presentation graphics. Italso includes low-level functions that allow you to fully

customize the appearance of graphics as well as to build

complete graphical user interfaces on your matlab

applications.

The matlab Application Program Interface (API):

This is a library that allows you to write C and FORTRAN

programs that interact with matlab. It includes facilities for

calling routines from matlab (dynamic linking), calling

matlab as a computational engine, and for reading and

writing MAT-files.



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Tool boxes of mat lab:

Signal processing:

The Signal Processing Blockset extends Simulink

with efficient frame-based processing and blocks for

designing, implementing, and verifying signal processing

systems. The blockset enables you to model streaming

data and multirate systems in communications,

audio/video, digital control, radar/sonar, consumer and

medical electronics, and other numerically intensive

application areas.

Embedded target for Motorola mp 555:

The Embedded Target for Motorola MPC555 lets

you deploy production code generated from Real-Time

Workshop Embedded Coder directly onto MPC5xx

microcontrollers. You can use the Embedded Target for



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Motorola MPC555 to execute code in real time on the

Motorola MPC5xx for on-target rapid prototyping,

production deployment of embedded applications, or

validation and performance analysis.

Real time window target:

Using Real-Time Workshop, you generate C code,

compile it, and start real-time execution on Microsoft

Windows while interfacing to real hardware using PC I/O

boards. Other Windows applications continue to run

during operation and can use all CPU cycles not needed

by the real-time task.

Real-Time Workshop:



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Real-Time Workshop generates and executes stand-

alone C code for developing and testing algorithms

modeled in Simulink. The resulting code can be used for

many real-time and non-real-time applications, including

simulation acceleration, rapid prototyping, and hardware-

in-the-loop testing.

Real-Time Workshop Embedded:

Real-Time Workshop Embedded Coder generates C

code from Simulink and State flow models that has the

clarity and efficiency of professional handwritten code.

The generated code is exceptionally compact and fast

essential requirements for embedded systems, on-target

rapid prototyping boards, microprocessors used in mass

production, and real-time simulators. You can use Real-

Time Workshop Embedded Coder to specify, deploy, and

verify production-quality software



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CHAPTER 8

SIMULINK

8. SIMULINK

8.1 Introduction to simulink:



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Simulink is a software add-on to matlab which is a

mathematical tool developed by The Math works a

company based in Natick. Matlab is powered by extensive

numerical analysis capability. Simulink is a tool used to

visually program a dynamic system (those governed by

Differential equations) and look at results. Any logic

circuit, or control system for a dynamic system can be built

by using standard building blocks available in Simulink

Libraries. Various toolboxes for different techniques, such

as Fuzzy Logic, Neural Networks, dsp, Statistics etc. are

available with Simulink, which enhance the processing

power of the tool. The main advantage is the availability of

templates / building blocks, which avoid the necessity of

typing code for small mathematical processes.

8.2 Concept of signal and logic flow:

In Simulink, data/information from various blocks

are sent to another block by lines connecting the relevant



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blocks. Signals can be generated and fed into blocks

dynamic / static).Data can be fed into functions. Data can

then be dumped into sinks which could be scopes, displays

or could be saved to a file. Data can be connected from one

block to another, can be branched, multiplexed etc. In

simulation, data is processed and transferred only at

discrete times, since all computers are discrete systems.

Thus, a simulation time step (otherwise called an

integration time step) is essential, and the selection of that

step is determined by the fastest dynamics in the simulated

system.



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Fig 8(a) Simulink library browser

8.3 Basic Elements:



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There are two basic

elements in simulink:

I) Blocks:are used to generate, modify,combine, output, and display signals.

ii)Lines: are used to transfer signals fromone block to another.

Blocks: There are several general classes of blocks:

Sources:Used to generate various signals

Sinks:Used to output or display signals

Linear: Linear, continuous-time system elements and

connections (summing junctions, gains,

etc.)

Nonlinear:Nonlinear operators (arbitrary functions,

saturation, delay, etc.)

Connections:Multiplex; Demultiplex, System Macros,

etc.



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. Blocks have zero to several input terminals and

zero to several output terminals. Unused input terminals

are indicated by a small open triangle. Unused output

terminals are indicated by a small triangular point. The

block shown below has an unused input terminal on the

left and an unused output terminal on the right.



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Lines: Lines can never inject a signal into another line;

lines must be combined th rough the use of a block such as

a summing junction

8.4: Connecting blocks:

Fig8(b) Connecting blocks



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Simulink is a graphical extension to MATLAB for

modeling and simulation of systems. In Simulink, systems

are drawn on screen as block diagrams. Many elements of

block diagrams are available, such as transfer functions,

summing junctions, etc., as well as virtual input and Output

devices such as function generators and oscilloscopes.

Simulink is integrated with MATLAB and data can be

easily transferred between the programs. When it starts,

Simulink brings up two windows. The first is the main

Simulink window, which appears as:



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The second window is a blank, untitled, model

window. This is the window into which a new model can

be drawn.



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A signal can be either a scalar signal or a vector signal.

For Single-Input, Single-Output systems, scalar signals

are generally used. For Multi-Input, Multi-Output

systems, vector signals are often used, consisting of two

or more scalar signals. The lines used to transmit scalar

http://www.library.cmu.edu/ctms/ctms/simulink/basic/split.mdl


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and vector signals are identical. The type of signal carried

by a line is determined by the blocks on either end of the

line.

Simple Example:



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The simplemodel (from the

model file section) consists of three blocks: Step, Transfer

Fun, and Scope. The Step is a source block from which a

step input signal originates. This signal is transfered

through the line in the direction indicated by the arrow to

the Transfer Function linear block. The Transfer Function

modifies its input signal and outputs a new signal on a

line to the Scope. The Scope is a sink block used to

display a signal much like an oscilloscope.

Modifying Blocks:

A block can be modified by double-clicking on it. For

example, if you double-click on the "Transfer Fun" block

in the simple model, you will see the following dialog

box.



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This dialog box contains fields for

the numerator and the denominator of the block's transfer

function. By entering a vector containing the coefficients

of the desired numerator or denominator polynomial, the

desired transfer function can beentered. For example, to

change the denominator to s^2+2s+1, enter the following

into the denominator field:



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[1 2 1]

And hit the close button, the model window will change

to the following,

This reflects the change in the denominator of the transfer

function.

The "step" block can also be double-clicked, bringing up

the following dialog box.



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The default parameters in this dialog box generate a

step function occurring at time=1 sec, from an initial level

of zero to a level of 1. The most complicated of these

three blocks is the "Scope" block. Double clicking on this

brings up a blank oscilloscope screen.



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When a simulation is performed, the signal which feeds

into the scope will be displayed in this window. Detailed

operation of the scope will not be covered in this tutorial.

The only function we will use is the autoscale button,

which appears as a pair of binoculars in the upper portionof the window.



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Running Simulations:

To run a simulation, we will work with the following

model file:

Before running a simulation of this system, first open the

scope window by double-clicking on the scope block.

Then, to start the simulation, either select Start from theSimulation



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The simulation should run very quickly and the

scope window will appear as shown below:



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Note that the simulation output (shown in yellow) is

at a very low level relative to the axes of the scope. To fix

this, hit the autoscale button (binoculars), this will rescale

the axes as shown below.

. Besides variable signals, and even entire systemscan be exchanged between MATLAB and Simulink.

Simulink is a platform for multinomial

simulation and Model-Based Design for dynamic systems.

It provides an interactive graphical environment and a

customizable set of block libraries, and can be extended for

specialized application blocks, left-click and drag the



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mouse from the output of one block to the input of another

block.

Sources and sinks:

The sources library contains the sources of data/signals

that one would use in a dynamic system simulation. One

may want to use a constant input, a sinusoidal wave, a step,

a repeating sequence such as a pulse train, a ramp etc. One

may want to test disturbance effects, and can use the

random signal generator to simulate noise. The clock may

be used to create a time index for plotting purposes. The

ground could be used to connect to any unused port, to

avoid warning messages indicating unconnected ports

The sinks are blocks where signals are terminated or

ultimately used. In most cases, we would want to store theresulting data in a file, or a matrix of variables. The data

could be displayed or even stored to a file. The stop block



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could be used to stop the simulation if the input to that

block (the signal being sunk) is non-zero. Figure 3 shows

the available blocks in the sources and sinks libraries.

Unused signals must be terminated, to prevent warnings

about unconnected signals.

Fig 8.(c) Sources and sinks



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Continuous and discrete systems: All dynamic systems

can be analyzed as continuous or discrete time systems.

Simulink allows you to represent these systems using

transfer functions, integration blocks, delay blocks etc.



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fig 8.(d)continous and discrete systems

Non-linear operators:



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A main advantage of using tools such as Simulink is

the ability to simulate non-linear systems and arrive at

results without having to solve analytically. It is very

difficult to arrive at an analytical solution for a system

having non-linearities such as saturation, signup function,

limited slew rates etc. In Simulation, since systems are

analyzed using iterations, non-linearities are not a

hindrance. One such could be a saturation block, to indicate

a physical limitation on a parameter, such as a voltage

signal to a motor etc. Manual switches are useful when

trying simulations with different cases. Switches are the

logical equivalent of if-then statements in programming.



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fig 8(e) simulink blocks

Mathematical operations:

Mathematical operators such as products, sum, logical

operations such as and, or, etc. .Can be programmed along

with the signal flow. Matrix multiplication becomes easy

with the matrix gain block. Trigonometric functions such

as sin or tan inverse (at an) are also available. Relational

operators such as equal to, greater than etc. can also be

used in logic circuits



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Fig 8(f) Simulink math blocks

Signals & data transfer:

In complicated block diagrams, there may arise the

need to transfer data from one portion to another portion of

the block. They may be in different subsystems. That signal

could be dumped into a goto block, which is used to send

signals from one subsystem to another.



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Fig 8(g) signals and systems

Making subsystems:

Drag a subsystem from the Simulink Library Browserand place it in the parent block where you would like to

hide the code. The type of subsystem depends on the

purpose of the block. In general one will use the standard



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subsystem but other subsystems can be chosen. For

instance, the subsystem can be a triggered block, which is

enabled only when a trigger signal is received. When ports

are created in the subsystem, they automatically create

ports on the external (parent) block. This allows for

connecting the appropriate signals from the parent block to

the subsystem.

Setting simulation parameters:

Running a simulation in the computer always requires

a numerical technique to solve a differential equation. The

system can be simulated as a continuous system or adiscrete system based on the blocks inside. The simulation

start and stop time can be specified. In case of variable step

size, the smallest and largest step size can be specified. A

Fixed step size is recommended and it allows for indexing

time to a precise number of points, thus controlling the size

of the data vector. Simulation step size must be decided

based on the dynamics of the system. A thermal process



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may warrant a step size of a few seconds, but a DC motor

in the system may be quite fast and may require a step size

of a few milliseconds.

SimDriveline :

SimDriveline extends Simulink with tools for

modeling and simulating the mechanics of driveline

systems. These tools include components such as gears,



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rotating shafts, and clutches; standard transmission

templates; and engine and tire models. SimDriveline is

optimized for ease of use and speed of calculation for

driveline mechanics. It is integrated with Math Works

control design and code generation products, enabling you

to design controllers and test them in real time with the

model of the mechanical system.

SimEvents:

SimEvents extends Simulink with tools for

modeling and simulating discrete-event systems using

queues and servers. With SimEvents you can create a

discrete-event simulation model in Simulink to model the

passing of entities through a network of queues, servers,

gates, and switches based on events.

Sim Power Systems:



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SimPowerSystems extends Simulink with tools for

modeling and simulating basic electrical circuits and

detailed electrical power systems. These tools let you

model the generation, transmission, distribution, and

consumption of electrical power, as well as its conversion

into mechanical power. SimPowerSystems is well suited

to the development of complex, self-contained power

systems, such as those in automobiles, aircraft,

manufacturing plants, and power utility applications.



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CHAPTER 9

SIMULATION RESULTS



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9. SIMULATION RESULTS

The designed transformer is at first simulated by using

simpower system block sets of the Matlab/Simulink

software. The inbuilt transformer blocks are used to

simulate the conceptual design. The appropriate turn ratiosare set in the dialog box and the simulation is run. Turn

ratios are shown in Table. Standard wire gauge SWG) is

shown in Table.



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Table: Design of the proposed transformer

A brief design description for the turn ratio, wire

gauge, and the geometry of the transformers are shown in

the Appendix. The simulation model is depicted in first fig

and the resulting input and output voltage waveforms are

illustrated in second fig.



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Fig. 9(a)Geometry of the transformer. Fig

9(b) Matlab/Simulink model of the three- to

five-phase transformation.



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It is balanced three-phase input. Individual output

phases are, also, shown along with their respective input

voltages. The phase Va is not shown because Va=Vx (i.e.,

the input and the output phases are the same). There was no

earth current flowing when both sides neutrals were

earthed. The input and output currents with earth current

waveforms are also shown in Fig. From this, we can say

that the transformer, connected to the X input line, carries

16.77% (19.5/16.7) more current than that of the other two

transformers (or two phases). Due to this efficiency, clearly

seen that the output is a balanced five-phase supply for a

overall transformer set is slightly lower than the

conventional three-phase transformer.



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Fig.9 (c) Input Vy and Vz phases and output Vb phase

voltage waveforms.9(d) Input Vy and Vx phases and

output Vc phase voltage waveforms.9 (e) Input Vz and Vx

phases and output Vd phase voltage waveforms



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CHAPTER 10

EXPERIMENTAL RESULTS

.



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10. EXPERIMENTAL RESULTS

This section elaborates the experimental setup

and the results obtained by using the designed three- to

five-phase transformation system. The designed

transformation system has a 1:1 input: output ratio, hence,

the output voltage is equal to the input voltage.

Nevertheless, this ratio can be altered to suit the step up or

step down requirements. This can be achieved by simply

multiplying the gain factor in the turn ratios. In the present

scheme for experimental purposes, three single phase

autotransformers are used to supply input phases of the

transformer connections. The output voltages can be

adjusted by simply varying the taps of the autotransformer.

For balanced output, the input must have balanced

voltages. Any unbalancing in the input is directly reflectedin the output phases. The input and output voltage

waveforms under no-load steady-state conditions are

recorded. The input and output voltage waveforms clearly


0


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show the successful implementation of the designed

transformer. Since the input-power quality is poor, the

same is reflected in the output as well. The output trace

shows the no-load output voltages. Only four traces are

shown due to the limited capability of the oscilloscope.

Further tests are conducted under load conditions on the

designed transformation system by feeding a five-phase

induction motor.

Fig.10 (a) Circuit diagram for a direct-online start of the

five-phase motor

Direct online starting is done for a five-phase

induction motor which is loaded by using an eddy-current


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load system. DC current of 0.5A is applied as the eddy-

current load on the five-phase induction machine. The

resulting input (three-phase) waveforms and the output

(five-phase) waveforms (voltages and currents) under

steady state. The applied voltage to the input peak-to-

peak). The corresponding waveforms of the same phase

A are equal to the input side voltage of 446 (peak-topic),

since the transformer winding has a 1:1 ratio. The power

factor is now reduced in the secondary side and is equal to

0.324 and the steady-state current reduces to 3.3 A (peak-

to-peak). The reduction in steady-state current is due to the

increase in the number of output phases. Thus, once again,

it is proved that the deigned transformation systems work

satisfactorily. The transient performance of the three- to

five-phase transformer is evaluated by recording the

transient current when supplying the five-phase inductionmotor load. The maximum peak transient current is

recorded as 7.04 A which is reduced to 4.32A in the

steady-state condition. The settling time is recorded to be


2


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equal to 438.4 ms. side is 446 V (peak to peak) , the power

factor is 0.3971, and the steady-state current is seen as

scopes


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4


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CHAPTER 11

APPENDIX


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11. APPENDIX

11.1Design of the transformer:

1) The volt per turn


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2) Standard core size of No. 8 of E and I was used whosecentral limb width is 2*2.54=5.08cm =50.8mm.

3) Standard size of Bakelite bobbin for 8 no. core of

3*2.54=7.62cm=76.2 mm was taken which will give core

area of 38.7096cm.

4) Turns of primary windings of all three single-phase

transformers are equal and the enamelled wire gauge is 15

SWG. The VA rating of each transformer is 2000.

Wire gauge was chosen at a current density of 4 A/mm

because enamelled wire was ofthe grade which can withstand the temperature up to 180.

The winding has 15 SWG wire because it carries the sum

of two currents (i.e., times the 5-phase

rated current).


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8


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CHAPTER 12

CONCLUSION

12. CONCLUSION

This paper proposes a new transformer connection

scheme to transform the three-phase grid power to a five-

phase output supply. The connection scheme and thephasor diagram along with the turn ratios are illustrated.

The successful implementation of the proposed connection

scheme is elaborated by using simulation and


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experimentation. A five-phase induction motor under a

loaded condition is used to prove the viability of the

transformation system. It is expected that the proposed

connection scheme can be used in drives applications and

may also be further explored to be utilized in multiphase

power transmission systems.


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CHAPTER 13

BIBILIOGRAPHY


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13. REFERENCES

[1] E. E. Ward and H. Harer, Preliminary investigation of

an inverter-fed 5-phase induction motor, Proc. Inst. Elect.

Eng., vol. 116, no. 6, 1969.

[2] A. Iqbal, Modeling and control of series-connected

five-phase and six-phase two-motor drive, Ph.D.

dissertation, Liverpool John Moores Univ., Liverpool,U.K., 2006.


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[3] G. K. Singh, Self excited induction generator research-

a survey, Elect. Power Syst. Res., vol. 69, pp. 107114,

2004.

[4] O. Ojo and I. E. Davidson, PWM-VSI inverter-

assisted stand-alone dual stator winding induction

generator, IEEE Trans Ind. Appl., vol. 36, no. 6, pp.

16041611, Nov./Dec. 2000.

[5] G. K. Singh, K. B. Yadav, and R. P. Saini, Modeling

and analysis of multiphase (six-phase) self-excited

induction generator, in Proc. Eight Int. Conf. on Electric

Machines and Systems, China, 2005, pp. 19221927.

[6] G. K. Singh, K. B. Yadav, and R. P. Sani, Analysis of

saturated multiphase (six-phase) self excited induction

generator, Int. J. Emerging Elect. Power Syst., Article 5,vol. 7, no. 2, Sep. 2006.


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