True Rms Converter Essays

I was so shocked that we can't use the brown vs board of education case in the thematic essay for the u.s regent today. #usregents #regnets

why do we write research papers ks2 hamza alavi essays about love. Taupunkt berechnen beispiel essay missing you shu ting analysis essay dissertation conclusion francais imageanzeige beispiel essay hypodermic needle theory essays data mining research papers 2016 camaro native american assimilation essay, pollution essay 50 words that sound oklahoma teacher of the year essays on education tunnelier 4 50 portable essays essay on harmful effects of unclean food places and eating joints? oklahoma teacher of the year essays on education handbook of personality theory and research paperback book death of a salesman setting essays essay on irish immigration to america you need to be doing that 10 pg essay shawty thanksgiving break essays essay quaid azam mohammad ali jinnah sociopolitical analysis essay english semester reflection essay bikes papel mojado analysis essay autoportrait courbet descriptive essay essay on addiction to drugs the intentional fallacy essay essay on railway track cross self introduction in korean essays words for essay small essay about divorce essay on unemployment problem in bhutan gemeinsam etwas planen beispiel essay american politics essay ap us history dbq essay american revolution research papers cyber security ap world history ccot essay 2006 gmc how to write an essay for us university common app essay violin radical essays on this thing called god individual reflective essay introduction Seeing how we see. New research paper on natural visual sensory input in cats � research papers on employee stress. An american president essays neural networks research papers list claudine movie essay on malcolm suny application essay letters, glass ceiling research paper list critical lens essay a raisin in the sun research paper on lgbt rights how to teach students to write an essay loanl'art philosophie terminale s dissertation short essay on nature dissertation marking quizzes, essay dancers shaw essay 2 carpet @redbull a well needed red bull to finish this essay!! when i am teaching i have my students read the uni trilateral commission papers and research those families who remain from manifest destiny is a four paragraph essay acceptable tv need help writing an essay quotations history essay introduction argument essay against smoking gunilla fincke dissertation writing abgabe dissertation uni frankfurt. Essay on role of media in english essay attention grabbers restaurants the great debate does god exist essay., disloyalty essay truth is evergreen essay research paper prospectus zodiac water the cycle of life essay 1500 word essay pages quotes *sneaks a couple Frozen and Walking Dead references into my essay* research papers on rice bran oil. moh diga essays what is mapping in essay writing capsim presentation essay apollo 11 research paper notebook propaganda ww2 essays website that writes essay for you name dr ezekiel emanuel atlantic essay 13 days film analysis essay essay on addiction to drugs dissertation conclusion francais different essays 4 main causes of world war 1 essay paper essay person who inspires me the most 500 words essay about myself essay 50 great essays pdf essayons wallpaper stores the abolitionist movement essay writing uw proctored essay 2016 ford how many pages for 500 word essay movie essays for college my goals in life essays wwu admissions essay for college? how many pages for 500 word essay, drawing on swachh bharat abhiyan essay quotes suggesting hamlet is mad essay assignment on argumentative essay, the best argumentative essay youtube my goals in life essays how long should a body paragraph be in a research paper. a picnic party essay 2nd year Essays marked. I guess that means it's time to graduate. See you soon, Sydney. carmilla le fanu analysis essay finance research paper proposal introductory paragraphs for argumentative essays on school truth and lies essay writer discovering myself essay for engineeringLyra belacqua descriptive essay the best moment essay causes of cold war essay the seagull reader essays key 2017 argument essay against smoking cod engine research paper My ENG 111 classes will be discussing this essay tomorrow: On Impact � via @newyorker major parts of research paper keshavn research papers to buy writing a good conclusion to a research paper used how to write an introductory paragraph essay help writing a thesis statement for a research paper uk. global regents thematic essay imperialism essays writers quote optometry essays merger and acquisition dissertation letter really good college essays zoning maps. Best persuasive essays ever written a mother in mannville essay dissertation lmu psychologie magazine. 500 days of summer genre analysis essays truth and lies essay writer? usc full time mba essay for engineers a good dissertation is a done dissertation pdf how to write essay for college application january 2017 abstracts for research papers year 2 natural selection short essay research paper on recycling waste list comparative words essays about love bressay field statoil austin harvard research papers journalism fauces de haakon analysis essay They're Here! College Application Essay Prompts from Yale, University of Chicago, and University of Texas � criterion video essay problems with social security essay. inanimate object essays lennie small character essay research paper of mechanical engineering vacancy 2017. Asa cover page for research paper writing for life paragraphs and essays 4th edition pdf. eid milan party essay iness ending words for essays research papers on rice bran oil capsim presentation essay impressive words to use in an argumentative essay 1981 hunger strike essay business administration degree essay persuasive essay linking words for opinion? soundscape essay in urban design? 5 year plan essay quotations writing a good thesis statement for a compare contrast essay powerpoint lnat essay student room oxford, essay on religious conversion should college essays be double spaced green card essay on time is a great healer lana del rey essay random block design analysis essay Hahah get this- my history exam was to write an in class 8 pg essay in an hour & my prof leisurely strolls in 10 min late. College is so fun sections of a dissertation graphs the secret life of bees coming of age essay judith lorber gender stratification essay is a four paragraph essay acceptable tv buy custom essay uk writers essay why want to be teacher essay on my achievements how to write an introduction for a summary essay news west point application essays propaganda ww2 essays discipline essay assignment greenberg modernism essays my best friend ever essay writer how to write a critical essay in higher english manchester dissertation binding taken essay why want to be teacher 3 article dissertation texting and driving research paper notes finding essays from scholar online submission of research papers research paper wikipedia query the luncheon short story analysis essay essay writing service review zoom 7 paragraph essay videos 12 essay 2 paragraphs about football essay essay on personal identity concussions in sports essay writing nature research papers youtube capitalism vs socialism essay newspaper how to write a medical research paper with answers pdf persuasive essay about responsibility how to write a lit review for a dissertation lawsuit.. Death of a salesman setting essays wood decay fungi research paper 12 essay chaucer canterbury tales research paper self introduction in korean essays save water essay 250 words liberty bell essay how to live a successful life essay steps to write a good essay zone research paper on comparative politics lord of the flies essay civilization vs savagery conclusion paragraph research paper on rain technology, peace train song analysis essays claremont mckenna supplement essay 2016 ford how to write a good essay for college xls? science project research paper expressions cybercrime essay conclusion help osu okc nursing admissions essay bcbsil 2016 application essay, mendelssohn scottish symphony analysis essay She started her essay with "college is no joke!!" Im crying pros and cons of gay marriage essay pdf buy dissertation online kijiji essay about bungee jumping florida thumb uni jena dissertation meaning? english essayists of romantic age how to write a timed persuasive essay merit and demerit of dowry system essay the merchant of venice shylock villain essay true life story essays custom essay writing service really good college essays zoning maps springboard american dream essays humans are inherently violent essay language is everything essay help comparative essay useful phrases in english about child abuse essay introduction @garyvee Your interview with Ryan H. inspired me to make a video essay on facing death, it features a clip of you 5 year plan essay quotations stem cell research argumentative essay key? frank walter steinmeier dissertation abstracts mill essay on bentham pdf.

Duke mba essay help essay on match fixing in ipl 2016 live match acknowledgements dissertation parents write a dissertation in a week numberbeauty of nature essay in marathi language essay writing on small scale industries pictures george orwell essays summary of the odyssey how to write a good essay in two hours. was it necessary to drop the atomic bomb on japan essay vues d en haut expository essays swot analysis of restaurant essays the merchant of venice shylock villain essay ramses ii essay true life story essays online relationships essay media critique essay school is kinda pointless now because they're setting our grades this week and I've handed in almost all my essays, I'm ready to graduate drunk driving opinion essay essay why want to be teacher karl marx essay graphic essay on borderline personality disordercauses and effects of world war 1 essay najoua belyzel docteur gel explication essay history essay introduction linking words for expository essays on mexico axinja hachfeld dissertation abstracts chorus in henry v analysis essay iness ending words for essays essay on dvaita philosophy perfume writing a hook for an essay powerpoint championnat karting lessay fair small essay about divorce myself essay in english for college students charles wheelan essays., writing a good science essay. Child centred education essay teachers critical lens essay on the bluest eye literary analysis essay of a poem extension 1 after the bomb essay lomba essay ip box positive and negative effects of imperialism essay hook good and bad leadership experiences essay research paper on recycling waste shayne higson euthanasia essay calc 1 final review essay debate speech on co education essay outsourcing food essay sarah michelson group experience essay cezaya dissertation, doing a research paper xls borreria hispida descriptive essay masculinity essay jokes masters dissertation writing book air guitar essays on art & democracy i love my country moldova essays. 5 year plan essay quotations alte dissertationen finden fr., want change world essay 5 movements to save environment essay.

Good and bad leadership experiences essay child and adolescent mental health dissertation, how to write a critical essay in higher english human computer interaction research papers qld dissertation on education us air guitar essays on art & democracy A beautiful essay on growing up & facing death. maharani gayatri devi school jaipur admissions essay l'art philosophie terminale s dissertation, research paper postpartum depression essay tommy morrison three words to describe yourself essay to enroll the best argumentative essay youtube becoming a teacher essay videos quotations in research papers zip code Writing a good poem is already tough. What more if you're going to understand critical essays of Freud, Lacan, Nietzsche, Barthes. taking notes for a research paper uk importance of study in dissertation broader perspectives essay issue 2011 movie? that moment when you need to finish an essay about friendship but you just had a fight with your best friend how to write a medical research paper with answers pdf stiff as a board light as a feather rakoff essays concluding an essay words introduction essay on difference between hollywood and bollywood look front page of research paper year compare and contrast essay on two common collector amplifier analysis essay, deckblatt eines essays online I have to write and Outline/Essay on "The Influence of Hip Hop on Youth". So anyone who wants to add a little input. Speak Up concluding an essay words introduction epromos analysis essay essay writing planner essay thesis for pride and prejudice characters how to write a personal essay about myself suny application essay letters quotations in research papers zip code nomos verlag dissertation meaning


Rated 4.7/5 based on 8034 customer reviews

Abstract
Now a days ,the issue of power quality is a major concerned area of research in
the power sector. With the advancement in technology, now it is possible to keep power
sector free from pollution. In the past few years, a lot of work have been done for the
reduction of the total harmonic distortion using different concepts and applications.
As a fundamental three-phase controllable ac-dc converter, the six-pulse
SCR rectifie is widely used in industry. However, it generates high Total Harmonic
Distortion (THD) in the line current. One of the solutions is to use multi-pulse rectifiers.
Multi-pulse rectifiers could be classified into the 12-, 18- and 24-pulse configurations.
Application examples include high voltage direct current transmission systems, high power
battery chargers and load commutated current source inverter powered motor drives.
Harmonics treatment can be performed by two methods: filtering and
cancellation. In filtering, the filters have their own harmonic so harmonic doesn’t reduce
much 3-phase Thyristor rectifiers have been used in industries for obtaining a variable DC
voltage, but they have a problem of including large lower order harmonics in the input
current. Various literatures have given idea that power quality can be improved with multi
pulse converter i.e. 12, 18 , 24 , 30 , 36 , 48 pulse converter. It consists of identical six pulse
converter units and may involve phase shifting transformers. By increasing number of pulse
we can reduce more harmonics.
Key words: Multi-pulse SCR rectifier, harmonic elimination, line current THD.
Sarvajanik college of engineering and technology, Surat 4
List of Figures:
Figure No Figure Description Page No
3.2.1 Six Pulse Rectifier 16
3.2.2 Waveform of the idealized six pulse SCR rectifier 18
Operating at alpha=0
3.3.1 Twelve Pulse Rectifier Circuit 19
3.3.2 Block diagram of Twelve Pulse Rectifier 19
3.3.3 Current waveform of the 12-pulse SCR rectifier 21
3.4.1 Current waveforms in the 12-pulse series-type rectifier 24
3.4.2 Harmonic spectrum of the rectifier currents 25
3.5 Typical current waveforms and harmonics contents of the 26
12- pulse SCR rectifier
3.6 Primary line current THD and input PF of the 27
12-pulse SCR rectifier.
4.1 Six Pulse Rectifier Simulation 28
4.1.1 Waveform of Six pulse Rectifier 29
4.2 Twelve Pulse Rectifier Simulation 30
4.2.1 Waveform of Twelve pulse Rectifier for alpha=0 31
4.2.2 Waveform of Twelve pulse Rectifier for alpha=30 32
4.2.3 Waveform of Twelve pulse Rectifier for alpha=60 33
4.2.4 Waveform of Twelve pulse Rectifier for alpha=90 34
4.3 Harmonic spectrum of current 35
4.4 MATLAB : Harmonic spectrum 36
5.1 TYN 612 38
5.2.1 TCA 785 39
5.2.2 Pin diagram of TCA 785 40
5.3.1 Hardware of six – pulse converter 41
5.3.2 Power circuit of six – pulse converter 42
5.3.3 Control circuit of six-pulse converter 43
5.4.1 Output voltage waveform for alpha = 0 degree 44
5.4.2 Output voltage waveform for alpha = 60 degree 44
Sarvajanik college of engineering and technology, Surat 5
5.4.3 Output voltage waveform for alpha = 130 degree 45
5.4.4 Output voltage waveform for alpha = 170 degree 45
5.4.5 Saw tooth waveform(Control part) 46
Sarvajanik college of engineering and technology, Surat 6
Table of Contents
Acknowledgement 3
Abstract 4
List of figures 5
Literature survey 9
CHAPTER-1: INTRODUCTION 10
1.1 Problem statement 10
1.2 Introduction to Power Quality Improvement 10
1.3 methods of eliminating harmonic current 12
1.4 Major Factors Contributing to Power Quality Issues 12
CHAPTER-2: POWER ELECTRONIC CONVERTER 14
2.1 Introduction 14
2.2 Types of Converters and Description 14
CHAPTER-3: MULTI-PULSE CONVERTER 15
3.1 Introduction 15
3.2 Six Pulse Converter 16
3.3 Twelve Pulse Converter 19
3.4 Input current waveform and Harmonic spectrum 23
3.5 Effect of Line and Leakage Inductance 26
3.6 THD and PF 27
CHAPTER-4: MATLAB SIMULATION 28
4.1 Six Pulse Converter 28
4.2 Twelve Pulse Converter 30
4.2.1 Waveform for alpha=0 degree 31
4.2.2 Waveform for alpha=30 degree 32
4.2.3 Waveform for alpha=60 degree 33
Sarvajanik college of engineering and technology, Surat 7
4.2.4 Waveform for alpha=90 degree 34
4.3 Current Waveform 35
4.4 THD 36
CHAPTER-5: HARDWARE IMPLEMENTATION 38
5.1 TYN 612 Thyristor 38
5.2 TCA 785 IC 39
5.3 Implementation of six-pulse converter 41
5.4 Output voltage waveforms for different firing angle 44
APPLICATION 47
RESULT ANALYSIS 48
REFERENCES 49
PPRs 50
BUSINESS MODEL CANVAS 52
BMC REPORT 53
Sarvajanik college of engineering and technology, Surat 8
LITERATURE SURVEY
 Power electronic converter harmonics : Multi-pulse methods foe clean power by
DEREK A. PAICE
 Ned Mohan, Tore M. Undeland and William P. Robbins,” Power Electronics:
Converter, Applications, and Design” Wiley, 3 edition (October 12,2002).
 P.S Bimbhra ,”Power Electronics”, Khana Publishers,New Delhi, 3rd Edition 2006.
 Power electronics: IEEE papers.
Sarvajanik college of engineering and technology, Surat 9
CHAPTER-1: INTRODUCTION
1.1 Problem statement:
To improve system power quality by reducing harmonics using multi-pulse converter.
1.2 Introduction to Power Quality Improvement
The IEEE defines POWER QUALITY as the ability of a system or an equipment to function
satisfactorily in its electromagnetic environment without introducing intolerable
electromagnetic interferences to anything in that environment.
Power quality plays an important role in supplying electricity effectively to the consumers.
The perfect power supply will be one which is like
(1)Any time available
(2)Good voltage and frequency within tolerances
(3)Has noise free sinusoidal wave shape.
As power becomes more essential and treasures resource for the entire world, it is important
to maintain its quality at all levels of usage for reliable working of apparatus.
IEEE standard defines electrical power quality as “the concept of powering and grounding
sensitive electronic equipment in a manner suitable for the equipment with precise wiring
system and other connected equipment”. It is deviation of voltage and currents from the ideal
or actual waveforms.
Sarvajanik college of engineering and technology, Surat 10
Quality of the power is decided by the end users. If the power apparatus works satisfactorily
for given supply then power is at good quality. If it doesn’t roles well or fails to work, then
power quality is poor.
Reasons for poor power quality or power quality issues are:
1. Harmonics
2. Transients
3. Voltage Fluctuations such as Voltage Sags & Swells
4. Interruptions e.g. Outages & Blinks
Power quality difficulties can produce significant problems in situations that include:
•important business applications (banking, inventory control, process control)
•critical industrial processes (programmable process controls, safety systems, monitoring
devices)
•essential public services (paramedics, hospitals, police, air traffic control)
Harmonic
Harmonics are sinusoidal voltages or currents having frequencies that are integer multiples
of the frequency at which the sup-ply system is designed to operate (termed the fundamental
frequency; usually 50 or 60 Hz). Harmonic distortion levels are described by the complete
harmonic spectrum with magnitudes and phase angles of each individual harmonic
component. It is also common to use a single quantity, the total harmonic distortion (THD),
as a measure of the effective value of harmonic distortion.
Sarvajanik college of engineering and technology, Surat 11
1.3 Methods to eliminate Harmonic Current:
To meet the restriction of IEEE Standard 519-1992, many methods could be applied to
eliminate or reduce harmonic currents generated by rectifiers. For example,
1) Using passive filters. Line reactors (inductors) are often used in conjunction
with capacitors in a rectifier to filter specific harmonic currents. However, the
connection of capacitors could cause resonance conditions that can magnify harmonic
current at certain frequency to a harmful level.
2) Using certain switching techniques. Switching techniques, for instance the
pulse width modulation technique, could be used to eliminate harmonic currents. In
high power applications, the premise for using these techniques is that the switching
devices must be the gate-turn-off type, such as GTOs or IGBTs .
3) Using multi-pulse rectifiers. Multi-pulse rectifiers are designed based on
phaseshifting transformers, which enable certain harmonics to be cancelled from the
rectifiers’ line currents. This method is especially practical for harmonic elimination
in high power applications.
1.4 Major Factors Contributing to Power Quality Issues:-
The three major factors contributing to the problems associated with power quality are:
(1) Use of Sensitive Electronic Loads
The electric utility system is designed to provide reliable, efficient, bulk power that is suitable
for the very large majority of electrical equipment. However, devices like computers and
digital controllers have been widely adopted by electrical end-users. Some of these devices
can be susceptible to power line disturbances or interactions with other nearby equipment
Sarvajanik college of engineering and technology, Surat 12
(2) The Proximity of Disturbance-Producing Equipment
Higher power loads that produce disturbances – equipment using solid state switching
semiconductors, arc furnaces, welders and electric variable speed drives – may cause local
power quality problems for sensitive loads.
(3) Source of Supply
Increasing energy costs, price volatility and electricity related reliability issues are expected
to continue for the foreseeable future. Businesses, institutions and consumers are becoming
more demanding and expect a more reliable and robust electrical supply, particularly with the
installation of diverse electrical devices. Compatibility issues may become more complex as
new energy sources and programs, which may be sources of power quality problems, become
part of the supply solution. These include distributed generation, renewable energy solutions,
and demand response programs
Utilities are regulated and responsible for the delivery of energy to the service entrance, i.e.,
the utility meter. The supply must be within published and approved tolerances as
approved by the regulator. Power quality issues on the “customer side of the meter” are the
responsibility of the customer. It is important therefore, to understand the source of power
quality problems, and then address viable solutions.
Sarvajanik college of engineering and technology, Surat 13
CHAPTER-2: POWER ELECTRONIC CONVERTER
2.1 Introduction:
The term “Converters” is used to refer a system which transforms one form of electrical
energy into another form of electrical energy.
The Power electronics converters uses a matrix of power semiconductor switches to convert
electrical power at high efficiency. The converter system consists of
(1)Switches (include two terminal devices such as diodes and three terminal devices such as
Thyristors).
(2) Reactive components L, C
(3) Transformer
These converters (also known as controllers) are generally classified into the following four
broad categories:
1) Rectifiers:
Conversion: From Fixed AC to Variable DC
2) Choppers:
Conversion: From Fixed DC to Variable DC
4) Inverters :
Conversion: From Fixed DC to AC of variable frequency and of Fixed or variable magnitude
5) AC to AC converters :
AC Regulators:
Conversion: From Fixed AC to variable AC at same frequency 17)-
Cyclo converters :
Conversion: From AC at one frequency to AC at another frequency through
one stage conversion.
Sarvajanik college of engineering and technology, Surat 14
Chapter-3: Multi-pulse rectifiers
3.1 INTRODUCTION:
Three phase 12 pulse controlled rectifiers are extensively used for converting AC to
DC. Higher pulse number means fewer input harmonics (better power factor), and smoother
output (smaller smoothing components).In phase controlled rectifiers though the output
voltage can be varied continuously the load harmonic voltage increases considerably as the
average value goes down. The magnitude of harmonic voltage is lower in 3-phase converter
compared to the 1-phase circuit.
Since the frequency of the harmonic voltage is higher than smaller load inductance leads
to continuous conduction. Input current wave shape become rectangular and contains higher
order odd harmonics. The displacement angle of the input current increases with firing angle.
The frequency of the harmonic voltage and current can be increased by increasing the pulse
number of the converter which can be achieved by series and parallel connection of basic
6pulse converters.
The rectifiers can be configured as 12-, 18- and 24-pulse rectifiers, powered by a phase
shifting transformer with a number of secondary windings. Each secondary winding feeds a
six-pulse diode rectifier. The main feature of the multi pulse rectifier lies in its ability to
reduce the line current harmonic distortion. This is achieved by the phase shifting
transformer, through which some of the low-order harmonic currents generated by the sixpulse
rectifiers are canceled. In general, the higher the number of rectifier pulses, the lower
the line current distortion is. The rectifiers with more than 30 pulses are seldom used in
practice mainly due to increased transformer costs and limited performance improvements.
The multi pulse rectifier has a number of other features. It normally does not require any LC
filters or power factor compensators, which leads to the elimination of possible LC
resonances. The use of the phase-shifting transformer provides an effective means to block
common-mode voltages generated by the rectifier and inverter in medium voltage drives,
Sarvajanik college of engineering and technology, Surat 15
which would otherwise appear on motor terminals, leading to a premature failure of winding
insulation.
3.2 Six Pulse Rectifier:
Fig (3.2.1): Simplified circuit diagram of a six-pulse SCR rectifier
Figure (3.2.1) shows a simplified circuit diagram for the six-pulse SCR rectifier, where RC
snubber circuits for the SCR devices are nomitted. The line inductance Ls represents the total
inductance between the utility supply and the rectifier, including the equivalent inductance of
the supply, the total leakage inductance of isolation transformer if any, and the inductance of
a three-phase line reactor that is often added to the system for the reduction of line current
THD. On the dc side of the rectifier, a dc choke Ld is used to smooth the dc current. The
choke is normally constructed with a single magnetic core and two coils, one coil in the
Sarvajanik college of engineering and technology, Surat 16
positive dc bus and the other in the negative bus. Such an arrangement is preferable in
medium-voltage drives since it helps to reduce the common-mode voltage imposed on the
motor without increasing the manufacturing cost of the choke. To simplify the analysis, it is
assumed that the inductance of the dc choke Ld is sufficiently high such that the dc current Id
is ripple-free.
Idealized Six-Pulse Rectifier:
Let’s consider an idealized six-pulse SCR rectifier, where the line inductance Ls in Fig. (3.2.1) is
assumed to be zero. Fig. (3.2.2) shows typical waveforms of the rectifier, where va, vb, and vc
are the phase voltages of the utility supply, ig1 to ig6 are the gate signals for SCR switches S1 to S6,
and α is the firing angle of the SCRs, respectively. During interval I (π/6 + α < ωt < π/2 + α) va is
higher than the other two phase voltages (vb and vc), making S1 forward-biased. When S1 is fired
at ωt = π/6 +α by its gate signal ig1, it is turned on. The positive dc bus voltage vP with respect to
ground G is equal to va. Assuming that S6 was conducting prior to the turn-on of S1, it continues
to conduct until the end of interval I, during which the negative bus voltage vN is equal to vb. The
dc output voltage can be found from vd = vP – vN = vab. The dc current Id flows from va to vb
through S1, the load, and S6. The three-phase line currents are ia = Id, ib = –Id, and ic = 0 as
shown in Fig. (3.2.2)
Sarvajanik college of engineering and technology, Surat 17
Fig (3.2.2): Waveforms of the idealized six-pulse SCR rectifier operating at α = 30°
Sarvajanik college of engineering and technology, Surat 18
3.3: 12- PULSE RECTIFIER
Fig (3.3.1) Circuit diagram of 12-pulse SCR rectifier:
Fig (3.3.2) Block diagram of a 12-pulse SCR rectifier:
Sarvajanik college of engineering and technology, Surat 19
The block diagram of a 12-pulse SCR rectifier is shown in Fig. 3.3.2 It is composed of a phaseshifting
transformer and two identical six-pulse SCR rectifiers. The transformer has two
secondary windings, one connected in star and the other in delta. The line-to-line voltage of the
secondary windings is normally half of its primary-currents, I’a and I’ã are the primary currents
referred from the secondary side, and iA is the primary line current given by iA = I’a + I’ã,
respectively.
The secondary line current ia can be expressed as
Where ω= 2πf1 is the angular frequency of the supply voltage. Since the waveform of ia is of halfwave
symmetry, it does not contain any even-order harmonics. In addition ia does not contain any
ripple harmonics either due to the balanced three phase system. The other secondary current iã
leads ia by 30°, and its Fourier expression is
The waveform for the referred current I’a in Fig. 3.3.3is identical to ia except that its magnitude
is halved due to the turns ratio of the Y/Y-connected windings. The current I’a can be expressed
in Fourier series as
Sarvajanik college of engineering and technology, Surat 20
Fig (3.3.3) Current waveforms of the 12-pulse SCR rectifier (Ls = Llk = 0) :
When the current iã is referred to the primary side, the phase angles of some harmonic
currents are altered due to the Y/Δ connected windings. As a result, the referred current I’ã
does not keep the same wave shape as iã.
Sarvajanik college of engineering and technology, Surat 21
The line current iA can be found from,
where the two dominant current harmonics, the 5th and 7th , are canceled in addition to the 17th
and 19th. The THD of the secondary and primary line currents ia and iA can be determined by
The THD of the primary line current iA in the idealized 12-pulse rectifier is reduced
approximately by 50% compared with that of the secondary line current ia.
Sarvajanik college of engineering and technology, Surat 22
3.4 Input current waveform and Harmonic spectrum:
Harmonic distortion:
 Description: Voltage or current waveforms assume non-sinusoidal
shape. The waveform corresponds to the
sum of different sine-waves with different magnitude and phase, having
frequencies that are multiples of
power-system frequency.
 Causes: Classic sources: electric machines working above the knee
of the magnetization curve (magnetic
saturation), arc furnaces, welding machines, rectifiers, and DC brush motors.
Modern sources: all non-linear
loads, such as power electronics equipment including ASDs, switched mode
power supplies, data processing
equipment, high efficiency lighting.
 Consequences: Increased probability in occurrence of resonance,
neutral overload in 3-phase systems,
overheating of all cables and equipment, loss of efficiency in electric machines,
electromagnetic interference
with communication systems, errors in measures when using average reading
meters, nuisance tripping of
thermal protections.
Figure 3.4.1 shows a set of simulated current waveforms of the rectifier operating
under the rated conditions. The line inductance Ls is assumed to be zero, and the total leakage
inductance Llk is 0.05 pu, which is a typical value for a phase-shifting transformer. The dc current
id is continuous, containing 12 pulses per cycle of the supply frequency. At any time instant
(excluding commutation intervals), the dc current id flows through four diodes simultaneously,
two in the top six-pulse rectifier and two in the bottom rectifier.
Sarvajanik college of engineering and technology, Surat 23
Fig. 3.4.1 Current waveforms in the 12-pulse series-type rectifier (Ls = 0, Llk = 0.05 pu, and IA1 =
1.0 pu).
The dc current ripple is relatively low due to the series connection of the two six-pulse rectifiers,
where the leakage inductances of the secondary windings can be considered in series. The
waveform of the line current ia in the star connected secondary winding looks like a trapezoidal
wave with four humps on the top. The waveform of iã in the delta-connected winding is identical
to ia except for a 30° phase displacement and is therefore not shown in the fig. The currents and
iã in
Figure. 3.4 is the secondary line currents ia and iã referred to the primary side. Since both primary
and top secondary windings are connected in star, the waveform of the referred current is identical
to that of ia except that its magnitude is halved due to the turns ratio of the two windings. When iã
is referred to the primary side, the referred current does not keep the same waveform as iã. The
changes in waveform are caused by the phase displacement of the harmonic currents when they
are referred from the delta-connected secondary winding to the star-connected primary winding. It
is the phase displacement that makes certain harmonics, such as the 5th and 7th, in out of phase
with those in .As a result, these harmonic currents are canceled in the transformer primary
winding and do not appear in the primary line current, given by
Sarvajanik college of engineering and technology, Surat 24
Fig. (3.4.2) shows the harmonic spectrum of the rectifier currents
Figure. (3.4.2), where, I’ãn, and IAn are the nth order harmonic currents (rms) in I’a, Iãn, and iA,
respectively. The harmonic content of the referred currents I’a and I’ã is identical, although their
waveforms are quite different. This is understandable since the harmonic content should not alter
when a secondary current is referred to the primary side. The magnitude of the 5th and 7th
harmonics is 18.6% and 12.4%, respectively, which are much higher than other harmonics. The
THD of the primary line current iA is only 8.38% in comparison to 24.1% of the secondary line
current ia. The substantial reduction in THD is owing to the elimination of dominant harmonics by
the phase-shifting transformer.
Sarvajanik college of engineering and technology, Surat 25
3.5: Effect of Line and Leakage Inductances :
Figure 3.5 shows typical current waveforms for the 12-pulse rectifier taking into account the
transformer leakage inductance Llk.
The rectifier operates under the condition of α= 0°, IA1 = 1 pu, Ls = 0 and Llk = 0.05 pu.
The waveform for the secondary line current ia is close to a trapezoid and contains the 5th
and 7th harmonics with a magnitude of 18.8% and 12.7%, respectively. However, these two
harmonics are canceled by the phase-shifting transformer, and thus they do not appear in the
primary line current iA. Due to the effect of the leakage inductance, the THD of iA is reduced
from 15.3% in the idealized rectifier to 8.61 %.
Fig 3.5 shows Typical current waveforms and harmonic contents of the 12-pulse SCR
rectifier with Ls = 0 and Llk = 0.05 p
Sarvajanik college of engineering and technology, Surat 26
3.6: THD and PF :
The THD of the primary line current iA as a function of IA1 and Ls is
illustrated in Fig 3.6. Compared with the six-pulse SCR rectifier, the 12-pulse rectifier has a
much better THD profile. The input power factor of the rectifier varies greatly with the firing
angle as shown in ,
Fig 3.6 Primary line current THD and input PF of the 12-pulse SCR rectifier.
Sarvajanik college of engineering and technology, Surat 27
Chapter-4: Matlab simulation
4.1 : Six – Pulse simulation :
Sarvajanik college of engineering and technology, Surat 28
Result:
4.1.1: Voltage waveform of the six pulse controlled
rectifier
Sarvajanik college of engineering and technology, Surat 29
4.2: twelve- Pulse simulation:
Sarvajanik college of engineering and technology, Surat 30
Output Voltage waveform:
4.2.1 Waveform for alpha=0 degree
Sarvajanik college of engineering and technology, Surat 31
4.2.2 Waveform for alpha =30 degree
Sarvajanik college of engineering and technology, Surat 32
4.2.3 Waveform for alpha=60 degree
Sarvajanik college of engineering and technology, Surat 33
4.2.4 Waveform for alpha=90 degree
Sarvajanik college of engineering and technology, Surat 34
4.3 Harmonic spectrum of the rectifier currents :
Figure where, I’ãn and I an are the nth order harmonic currents (rms)
in I’a, Iãn, and iA, respectively.
Sarvajanik college of engineering and technology, Surat 35
4.4: MATLAB simulation of harmonics:
Sarvajanik college of engineering and technology, Surat 36
4.5 Solution of power quality problems:
The mitigation of PQ problems may take place at different levels: transmission, distribution
and the endues equipment. As seen in Fig. 4.5 several measures can be taken at these levels.
Fig.4.5 solution of power quality problems
Sarvajanik college of engineering and technology, Surat 37
Chapter-5: Hardware Implementation
5.1: TYN612 SCRs:
Description:
Glass passivated ,sensitive gate thyristor in plastic envelope,intended for use in general
purpose switching and phase control applications. These devices are intended to be interfaced
directly to microcontrollers,logic intergrated circuits and other low power gate trigger circuits.
Fig 5.1: TYN612
K: cathode , A:anode , G:gate
Application of tyn612:
 Motor control
 Industrial and domestic lighting
 Heating
 Static switching
Features:
 Blocking voltage to 600 V
 On –state RMS current to 12 A
 Ultra low gate trigger current
Sarvajanik college of engineering and technology, Surat 38
5.2: TCA 785 (Phase Control IC)
Fig 5.2.1: TCA 785
Description:
This phase control IC is intended to control thyristors,triacs and transistors. The trigger
pulse can be shifted within a phase angle between 0 degree and 180 degree.
Application:
 Ac phase control
 Three phase current controllers
Features:
 Reliable recognition of zero passage
 Large application scope
 May be used as zero point switch
 LSL compatible
 Three phase operation possible (3 ICs)
 Output current 250 mA
 Large ramp current range
 Wide temperature range
Sarvajanik college of engineering and technology, Surat 39
Fig 5.2.2: Pin-Diagram of TCA 785:
Sarvajanik college of engineering and technology, Surat 40
5.3: Hardware Implementation of 6 pulse converter:
Fig 5.3.1:
Sarvajanik college of engineering and technology, Surat 41
Fig 5.3.2: Power Circuit(6-Pulse Converter)
Sarvajanik college of engineering and technology, Surat 42
Fig 5.3.3: Control circuit for 6 pulse converter:
Sarvajanik college of engineering and technology, Surat 43
5.4: Output Voltage Waveforms for different firing angle:
Fig 5.4.1: alpha=0 degree
Fig 5.42: alpha = 60 degree
Sarvajanik college of engineering and technology, Surat 44
Fig 5.4.3: alpha = 130 degree
Fig 5.4.4: alpha=170 degree
Sarvajanik college of engineering and technology, Surat 45
Fig 5.4.5: Saw tooth waveform (control part):
Sarvajanik college of engineering and technology, Surat 46
APPLICATION:
➢ Three-phase controlled rectifier have a wide range of applications, from small
rectifiers to large High Voltage Direct Current (HVDC) transmission systems.
➢ They are used for electro-chemical process, many kinds of motor drives, traction
equipment, controlled power supplies and many other applications
➢ In modern power electronics converters, a three-phase controlled converter is
commonly used especially as a rectifier in interfacing adjustable speed drives and renewable
energy in electric utilities.
Sarvajanik college of engineering and technology, Surat 47
RESULT ANALYSIS:
From the results obtained through the simulations of 6-pulse controlled converter
and 12-pulse controlled converter using MATLAB simulink software. We study the various
effects of Load variation on system performance and Power supply system like Factor,
Harmonics etc.
By simulating various conditions we observe the adverse effects and how to
overcome them for optimal system operation. And we also study the relative advantages of
multi pulse converter.
Sarvajanik college of engineering and technology, Surat 48
REFERENCES:
 Power electronic converter harmonics : Multi-pulse methods foe clean power by
DEREK A. PAICE
 Ned Mohan, Tore M. Undeland and William P. Robbins,” Power Electronics:
Converter, Applications, and Design” Wiley, 3 edition (October 12,2002).
 P.S Bimbhra ,”Power Electronics”, Khana Publishers,New Delhi, 3rd Edition 2006.
 M.H Rashid,” Power Electronics: Circuit, Devices and Applications’, Prentice hall.3rd
edition ,2003.
 Power electronics: IEEE papers.
 TYN612:data sheet
Sarvajanik college of engineering and technology, Surat 49
PPRS:
Periodic Progess Report : First PPR
Project: Power Quality Improvement By Multi-Pulse AC-DC Converters: Simulation
,Design & Implementation
Status: Reviewed (Freeze)
1. What Progress you have made in the Project?
Ans :we have made 3 phase transformer and working on the control part.
2. What challenge you have faced?
Ans: we have faced problem in firing of SCR (control circuit)
3. What support you need?
Ans: we need support to understand the working of IC which we are using in project.
4. Which literature you have referred?
Ans: Power electronic converter harmonics : Multi-pulse methods foe clean power by
DEREK A. PAICE
Periodic Progess Report : Second PPR
Project:Power Quality Improvement By Multi-Pulse AC-DC Converters: Simulation,Design
& Implementation
Status : Reviewed (Freeze)
1. What Progress you have made in the Project ?
we are working on control circuit.
2. What challenge you have faced ?
we have faced problem to compare the two waveform to get the gate pulse.
3. What support you need ?
we need support in control circuit.
4. Which literature you have referred ?
Ned Mohan, Tore M. Undeland and William P. Robbins,” Power Electronics: Converter,
Applications, and Design” Wiley,
3 edition (October 12,2002).
Sarvajanik college of engineering and technology, Surat 50
Periodic Progess Report : Third PPR
Project:Power Quality Improvement By Multi-Pulse AC-DC Converters: Simulation,Design
& Implementation
Status : Reviewed (Freeze)
1. What Progress you have made in the Project ?
we are making power circuit .
2. What challenge you have faced ?
we have faced challenge in firing of SCRs.
3. What support you need ?
we need support to get clear idea about the TYN612 and its data sheet.
4. Which literature you have referred ?
Power electronics: IEEE papers.
Periodic Progess Report : Forth PPR
Project: Power Quality Improvement By Multi-Pulse AC-DC Converters: Simulation,Design
& Implementation
Status: Reviewed (Freeze)
1. What Progress you have made in the Project?
Ans: we have made the 3 phase transformer and working on power circuit.
2. What challenge you have faced?
Ans: we have faced problem in power circuit.
3. What support you need?
Ans: we need support to understand about the characteristics of tyn612.
4. Which literature you have referred?
Ans: Power electronics: IEEE papers.
Sarvajanik college of engineering and technology, Surat 51
The Business model canvas:
Sarvajanik college of engineering and technology, Surat 52
BMC REPORT:
The Business Model Canvas is a strategic management and lean start-up template for
developing new or documenting existing business models. It is a visual chart with elements
describing a product’s value, infrastructure, customers, and finances. It assists firms in
aligning their activities by illustrating potential trade-offs.
Formal descriptions of the business become the building blocks for its activities. Many
different business conceptualizations exist but the following model proposes a single
reference model based on the similarities of a wide range of business model
conceptualizations. With this business model design template, an enterprise can easily
describe their business model.
The Canvas has nine elements which are as follows:
(1) Value Propositions: It includes problems and needs of the persons that we are going to
solve and satisfy through our product and various reasons for which they would like to
choose our product over the rest.
The various value proposition of our product are as follows:
• Performance.
• Effective cost.
• Power factor improvement
• Smooth dc output voltage
(2) Customer Segments: To build an effective business model, a company must identify
which customers it tries to serve. Various sets of customers can be segmented based on the
different needs and attributes to ensure appropriate implementation of corporate strategy
meets the characteristics of selected group of clients. This section mainly focuses on three
things: Segment Dimensions, Segment composition and Problems, Needs, Habits & Current
Alternatives.
The following are our customer segments:
• SMALL SCALE INDUSTRY
• LARGE SCALE INDUSTRY
(3) Channels: A company can deliver its value proposition to its targeted customers through
different channels. Effective channels will distribute a company’s value proposition in ways
that are fast, efficient and cost effective. An organization can reach its clients either through
its own channels, partner channels or a combination of both.
The channels which we may use are:
 ONLINE SELLING
 WORD OF MOUTH
 TRADE FAIR
Sarvajanik college of engineering and technology, Surat 53
(4) Customer Relationship: To ensure the survival and success of any businesses, companies
must identify the type of relationship they want to create with their customer segments. When
it comes in increasing profits, it\’s tempting to concentrate on making new sales or pursuing
bigger accounts. But attention to your existing customers, no matter how small they are, is
essential to keeping your business thriving.
The following will be our initiatives to build strong Customer Relationship:
• AFTER SALES SUPPORT
• SERVICE ON SITE
(5) Key Activities: These are the crucial things the business needs to do to deliver on its
propositions and make the rest of the business work. For a product-driven business, this
includes ongoing learning about users and new techniques to build better product. If you’re
focused on doing a bunch of things for a particular set of customers, it includes maintaining
superior expertise on the segment(s) and creating or acquiring products and services that are a
good fit, whatever that entails. Similarly for an infrastructure business, it includes keeping the
infrastructure working reliably and making it more efficient.
The key activities of our business model are as follows:
• SELECTION OF RATING OF TRANSFORMER AND SCR
• ASSEMBLY
• TESTING
(6) Key Resources: These are the resources that are necessary to create value for the
customer. They are considered an asset to a company, which are needed in order to sustain
and support the business. These resources could be human, financial, physical and
intellectual. Key resources are the strategic assets you need in place, and you need in place to
a greater or more targeted degree than your competitors.
The following are our key resources:
• MATERIAL
• MACHINING FACILITY
• LABOUR
(7) Key Partners: In order to optimize operations and reduce risks of a business model,
organization usually cultivate buyer-supplier relationships so they can focus on their core
activity. Complementary business alliances also can be considered through joint ventures,
strategic alliances between competitors or non-competitors. Hence identifying Key Partners is
important for any Business Model.
The following constitute as our key partners:
• MATERIAL SUPPLIER
• MACHINE SHOP
• TOOL SUPPLIER
Sarvajanik college of engineering and technology, Surat 54
(8) Revenue Streams: A revenue stream is a form of revenue. It is considered one of the
building blocks of a business model canvas that reveals the earning a business makes from all
the methods by which money comes in. Revenue streams may be characterized. For example,
a revenue stream has volatility, predictability, risk, and return. Thus, a revenue stream is a
way of categorizing the earnings a company makes.
Our revenue stream can be divided into following parts:
• SELLING OF PRODUCT
• PAID SERVICE
• COMPONENT REPLACEMENT
• INHOUSE WORK
(9) Cost structure: This phase describes the most important monetary consequences while
operating under different business models. There are 2 types of Business Structures – Cost-
Driven & Value-Driven, and the cost structure differs accordingly. It includes the various
types of costs (Fixed & Variable) and different activities that contribute to Total cost are to be
included.
Our cost structure segmentation is as follows:
• RAW MATERIAL
• MARKETING
• INFRASTRUCTURE FACILITY
This Business Model Canvas Report takes into account almost every element of the Business
Model Canvas prepared by our team in line with our Business Model Proposal. This Report
may serve as a primary document which may describe our Business Concept Model
Sarvajanik college of engineering and technology, Surat 55

One thought on “True Rms Converter Essays

Leave a Reply

Your email address will not be published. Required fields are marked *