SIMULATION OF REDUCED SWITCH INVERTER BASED UPQC WITH FUZZY LOGIC AND ANN CONTROLLERS

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SIMULATION OF REDUCED SWITCH INVERTER BASED UPQC WI TH

FUZZY LOGIC AND ANN CONTROLLERS

SHAIK. MABUSUBANI 1 & SURESH KORNEPATI 2

1PG Student, Department of EEE, Sri Mittapalli College of Engineering, Guntur, Andhra Pradesh, India 2Associate Professor, Head, Department of EEE, Sri Mittapalli College of Engineering, Guntur, Andhra Pradesh, India

ABSTRACT

This paper presents a new methodology to reduce harmonic distortion in UPQC using artificial neural network

and fuzzy logic controller. So this paper main aim is improve power quality by using UPQC with ANN and FLC. The most

purpose of the proposed (ANN & FLC) is capable of providing good static and dynamic performances compared to PI

controller. The UPQC is to control on voltage flicker/unbalance, reactive power and harmonics. In different words, the

UPQC has the potential of up power quality at the purpose of installation on power industrial power systems.

The appliance of computing is growing quick within the space of power electronics and drives. From olden days to now

days we are using twelve switches used in back to back configuration. But now we are using nine switches instead of 12

switches. In 9 switch UPQC converter given the most useful benefits compared to 12 switches power converter. The nine

switches UPQC converter gets the best results by using of three methods. They are one is PI controller technique, ANN

controller technique and FLC controller technique. By contrast PI, FLC and ANN, ANN is better than (FLC & PI) for

power quality enhancement and voltage sag and voltage swell mitigations. The factitious neural network (ANN) is taken

into account as a replacement tool to style management electronic equipment for power-quality (PQ) devices. A whole

simulation study is administrated to analysis the performance of the ANN controller and compares its performance with the

quality FLC & PI controller’s results. The nine-switch convertor has already been proved to possess sure benefits,

additionally to its part saving topological feature. Despite these benefits, the nine-switch convertor has thus far found

restricted applications because of its several perceived performance tradeoffs like requiring associate degree outsized

dc-link capacitance, restricted amplitude sharing, and unnatural part shift between its 2 sets of output terminals. Rather

than acceptive these tradeoffs as limitations, a nine-switch power conditioner is projected here that nearly “converts” most

of those topological short comings into fascinating performance benefits. Aiming more to cut back its switch losses,

Harmonics, Voltage Sag & Swell associate degree acceptable discontinuous modulation theme is projected and studied

here thoroughly to doubly make sure that top reduction of commutations is achieved. With associate degree suitably

designed management theme with PI and ANN with Fuzzy logic controller then incorporated, the nine-switch convertor is

shown to favorably raise the general power quality in Simulation, thus justifying its role as an influence conditioner at a

reduced value.

KEYWORDS: ANN, Active Power Filters, PI Controller, Nine Switch Converter, Power Quality, UPQC

INTRODUCTION

The prime objective of power utility companies is to provide their consumers an uninterrupted sinusoidal voltage

of constant amplitude [1]-[5]. In addition to this, adherence to different power quality standards laid down by different

International Journal of Electrical and Electronics Engineering Research (IJEEER) ISSN(P): 2250-155X; ISSN(E): 2278-943X Vol. 4, Issue 6, Dec 2014, 77-94 © TJPRC Pvt. Ltd.

78 Shaik. Mabusubani & Suresh Kornepati

Impact Factor (JCC): 5.9638 Index Copernicus Value (ICV): 3.0

agencies has become a figure of merit for the power utilities [6]. Unfortunately, this is becoming increasingly difficult to

do so, because

The size and number of non-linear and poor power Factor loads such as adjustable speed drives, computer power

supplies, furnaces, power converters and traction drives are finding its applications at domestic and industrial levels.

These nonlinear loads draw non-linear current and degrade electric power quality. The quality degradation leads to low

power-factor, low efficiency, overheating of transformers and so on [2]. The power electronic devices as a result of their

inherent non-linearity draw harmonic and reactive power from the availability. In 3 phase systems; the reactive power

burden, injected harmonics, excessive neutral currents and unbalance cause low system potency and poor power factor.

Additionally to the present, the ability system is subjected to numerous transients like voltage sags, swells, glints etc.

These transients would have an effect on the voltage at distribution levels. Excessive reactive power of loads would

increment the generating capability of generating stations and increment the transmission losses in lines. Thus provide of

reactive power at the load end becomes essential.

Power Quality (PQ) chiefly deals with problems like maintaining a set voltage at the purpose of Common

Coupling (PCC) for varied distribution voltage levels regardless of voltage fluctuations, maintaining close to unity power

issue power drawn from the supply, obstruction of current and voltage unbalance from passing upwards from varied

distribution levels, reduction of current and voltage harmonics within the system and suppression of excessive provide

neutral current.

Nowadays equipments exploitation power semiconductor devices, usually called active power filters (APF’s),

Active Power Line Conditioners (APLC’s) etc. are used for the power quality problems owing to their dynamic and

adjustable solutions [10]. This paper is intended to provide a comprehensive review on the topic of UPQC. Over 10

publications [1]-[11] are critically reviewed to get proper idea about different intelligent controller used with UPQC.

Beside this, this paper also discusses the most significant concepts that are utilized to control the UPQC.

Since its initial introduction, static power convertor development has full-grown quickly with several convertor

topologies currently pronto found within the open literature. Incidental this development is that the equally speedy

identification of application areas, wherever power converters will contribute absolutely toward raising the general system

quality [1], [2]. In most cases, the known applications would need the ability converters to be connected nonparallel [3] or

shunt [4], looking on the operational situations into consideration. Additionally, they have to be programmed with voltage,

current, and power regulation schemes in order that they will swimmingly make amends for harmonics, reactive power

flow, unbalance, and voltage variations. For even additional tight regulation of provide quality, each a shunt and a series

convertor square measure more with one amongst them tasked to perform voltage regulation, whereas the opposite

performs current regulation. nearly always, these 2 converters square measure connected in an exceedingly back to-back

configuration [5], victimization twelve switches in total and sharing a typical dc-link capacitance, as mirrored by the

configuration drawn in Figure 1(a). Wherever obtainable, a small supply may be inserted to the common dc link, if the

intention is to supply for distributed generation in an exceedingly small grid [6], while not considerably impacting on the

long proved correct functioning of the succeeding configuration.

Presenting a much better reduced semiconductor different for top quality series–shunt compensation, this paper

proposes one stage integrated nine-switch power conditioner, whose circuit association is shown in Figure 1(b). As its

name roughly inferred, the planned conditioner uses a nine-switch convertor with 2 sets of output terminals, rather than the

Simulation of Reduced Switch Inverter Based UPQC with Fuzzy Logic and ANN Controllers 79


same old twelve switch back-to back convertor. The nine-switch convertor was earlier planned in [7] and [8] at regarding a

similar time, and was counseled for twin motor drives [9], rectifier–inverter systems, and uninterruptible power provides

[10]. Despite functioning as supposed, these applications are burdened by the restricted part shift and strict amplitude

sharing enforced between the 2 terminal sets of the nine-switch convertor.

During voltage sags, the second set of management schemes conjointly has the flexibility to endlessly keep the

load voltages inside tolerable vary. This sag mitigation ability, along with different abstract findings mentioned during this

paper however not within the open literature, has already been verified in experiment with favorable results discovered.

Figure 1: (a) Back-To-Back and (b) Nine-Switch Power Conditioners

POWER QUALITY

Power Quality (PQ) connected problems are a unit of most concern today. The widespread use of equipment, like

info technology instrumentality, power physical science like energy-efficient lighting, adjustable speed drives (ASD), PLC,

diode to a whole modification of electrical hundreds nature. These hundreds area unit at the same time the key causers and

also the major victims of power quality issues [8]. Because of their non-linearity, of these hundreds cause disturbances

within the voltage undulation. Alongside technology advance, the organization of the worldwide economy has evolved

towards globalization and also the profit margins of the many activities tend to decrease [11]. The magnified sensitivity of

the overwhelming majority of processes (services, residential and even industrial) to PQ issues turns the provision of

electrical power with quality an important issue for fight in each activity sector. The foremost crucial area units are the

continual method trade and also the info technology services. Once a disturbance happens, immense money losses could

happen, with the ensuing loss of productivity and fight. Though several efforts are taken by utilities, some shoppers need

tier of PQ beyond the extent provided by fashionable electrical networks. This means that some measures should be taken

so as to attain higher levels of Power Quality.



UNIFIED POWER QUALITY CONDITIONER

The Unified Power Quality Conditioner may be a custom power device that is used within the distribution system

to mitigate the disturbances that have an effect on the performance of sensitive and/or essential load. It is a kind of hybrid

APF and is that the solely versatile device which might mitigate many power quality issues connected with voltage and

current at the same time thus is multi functioning devices that compensate numerous voltage disturbances of the ability

offer, to correct voltage fluctuations and to stop harmonic load current from getting into the ability system. The system

configuration of a single-phase UPQC is shown in Figure 2. Unified Power Quality Conditioner (UPQC) consists of 2

IGBT primarily based Voltage supply converters (VSC), one shunt and one series cascaded by a typical DC bus. The shunt

convertor is connected in parallel to the load. It provides power unit support to the load and provides harmonic currents.

Whenever {the offer the availability the provision} voltage undergoes sag then series convertor injects appropriate voltage

with supply [2]. Therefore UPQC improves the ability quality by preventing load current harmonics and by correcting the

input power issue. the most elements of a UPQC square measure series and shunt power converters, DC capacitors,

low-pass and high-pass passive filters, and series and shunt transformers the most purpose of a UPQC is to catch up on

offer voltage power quality problems, such as, sags, swells, unbalance, flicker, harmonics, and for load current power

quality issues, such as, harmonics, unbalance, reactive current, and neutral current. The key elements of this technique

square measure as follows.

• 2 inverters —one connected across the load that acts as a shunt APF and different connected nonparallel with the

road as that of series APF.

• Shunt coupling inductance Lsh is employed to interface the shunt electrical converter to the network. It conjointly

helps in smoothing this wave. Generally associate isolation electrical device is employed to electrically isolate the

electrical converter from the network.

• a typical dc link that may be fashioned by employing a condenser or associate inductance. In Figure 2, the dc link

is accomplished employing a condenser that interconnects the 2 inverters and conjointly maintains a continuing

independent dc bus voltage across it.

• Associate LC filter that is a passive low-pass filter (LPF) and helps to eliminate high-frequency switch ripples on

generated electrical converter output voltage.

• Series injection electrical device that is accustomed connect the series electrical converter within the network.

An acceptable flip magnitude relation is commonly thought-about to scale back the voltage and current rating of

series electrical converter.

In principle, UPQC is associate integration of shunt and series APFs with a typical independent dc bus. The shunt

electrical converter in UPQC is managementled in current management mode such it delivers a current that is adequate to

the set price of the reference current as ruled by the UPQC control algorithmic program. To boot, the shunt electrical

converter plays a vital role in achieving needed performance from a UPQC system by maintaining the dc bus voltage at a

group reference price. So as to cancel the harmonics generated by a nonlinear load, the shunt electrical converter ought to

inject a current. Similarly, the series electrical converter of UPQC is managementled in voltage control mode such it

generates a voltage and injects nonparallel with line to realize a curved, free from distortion and at the required magnitude

voltage at the load terminal. Within the case of a voltage sag condition, actual supply voltage can represent the distinction



between the reference load voltage and reduced offer voltage, i.e., the injected voltage by the series electrical converter to

take care of voltage at the load terminal at reference price. Altogether the reference papers on UPQC, the shunt electrical

converter is operated as controlled current supply and also the series electrical converter as controlled voltage supply

except during which the operation of series and shunt inverters is interchanged.

A unified power quality conditioner (UPQC) may be a device .The UPQC, sort of a UPFC, employs 2 voltage

supply inverters (VSIs) that area unit connected to a standard dc energy storage condenser. One among these 2 VSIs is

connected serial with the AC line whereas the opposite is connected in shunt with an equivalent line. A UPFC is used in an

exceedingly power gear mechanism to perform shunt and series compensation at an equivalent time. Equally a UPQC may

perform each the tasks in an exceedingly power distribution system. However, at now similarities within the operational

principles of those 2 devices finish. Since an influence cable typically operates in an exceedingly balanced, distortion

(harmonic) free surroundings, a UPFC should solely give balanced shunt or series compensation. An influence distribution

system, on the other hand, could contain unbalance, distortion and even dc elements. Thus a UPQC should operate below

these surroundings whereas providing shunt or series compensation.

The UPQC may be a comparatively new device and not a lot of work has been reported thereon however. It has

been viewed as an integration of series and shunt active filters. It has been shown that it may be accustomed attenuate

current harmonics by inserting a series voltage proportional to the road current. Instead, the inserted series voltage is

supplemental to the voltage at the purpose of common coupling specified the device will give a buffer to eliminate any

voltage dip or flicker. It is additionally potential to control it as a mixture of those 2 modes. In either case, the shunt device

is employed for providing a path for the important power to flow to assist the operation of the series connected VSI.

Additionally enclosed during this structure may be a shunt passive filter to that all the comparatively low frequency

harmonics area unit directed.

Figure 2: UPQC General Block Diagram

OVERALL CONTROL CIRCUIT CONFIGURATION OF NINE SWITC H UPQC

Reference Generation (Phase Locked Loop)

Reference currents and voltages square measure generated victimization part secured Loop (PLL).

The management strategy is predicated on the extraction of Unit Vector Templates from the distorted input provide.

These templates are going to be then adore pure curving signal with unity (p.u.) amplitude. The 3-ph distorted input supply

voltage at PCC contains basic element and distorted element. To induce unit input voltage vectors Uabc, the input voltage

is perceived and increased by gain adequate to 1/Vm, wherever Vm is adequate to peak amplitude of basic input voltage.



These unit input voltage vectors square measure taken to part secured loop (PLL). With correct part delay, the unit vector

templates square measure generated.

The extraction of unit vector templates is

sin( )

sin( 120 )

sin( 120 )

a

b

c

U wt

U wt

U wt

== − °= + °

Multiplying the height amplitude of basic input voltage with unit vector templates of above equation offers the

reference load voltage signals,

* .abc m abcV V U=

Figure 3: Extraction of 3-Φ Reference Voltages Unit Vector Templates

In order to own distortion less load voltage, the load voltage should be adequate to these reference signals.

The measured load voltages square measure compared with reference load voltage signals. The error generated is then

taken to a physical phenomenon controller to get the desired gate signals for series APF. The unit vector templates are

often applied for shunt APF to compensate the harmonic current generated by non-linear load. The shunt APF is employed

to catch up on current harmonics likewise on maintains the dc link voltage at constant level. To realize the higher than

mentioned task the dc link voltage is perceived and compared with the reference dc link voltage. A PI controller then

processes the error. The signal from PI controller is increased with unit vector templates of equation (1) giving reference

supply current signals. The supply current should be adequate to this reference signal. So as to follow this reference current

signal, the 3-ph supply currents square measure perceived and compared with reference current signals. The error

generated is then processed by a physical phenomenon current controller with appropriate band, generating gating signals

for shunt APF.

CONTROL STRATEGY OF NINE SWITCH UPQC

Static Shunt Compensator Using PI

Nine Switch UPQC consists of shunt compensator and series compensator. The shunt compensator is

managementled by a PWM current control formula, whereas the series convertor is managementled by a PWM voltage

control formula. In step with the adopted management theme, these 2 components of 9 Switch UPQC have totally different

functions as follows:



Figure 4: Control Block Diagram of Shunt Inverter Using PI

Shunt electrical converter management in interconnected mode: Mode one of shows UPQC shunt voltage supply

electrical converter dominant diagram applying synchronous coordinate system theory technique wherever sensitive load

currents area unit Ia, Ib and Ic

00

dqldq abc abcI T I=

(1)

0

2 2cos cos cos

3 3

2 2 2sin sin sin

3 3 3

1 1 1

2 2 2

dqabcT

π πθ θ θ

π πθ θ θ θ θ

− +

= − −

(2)

,ld ld ld lq lq lqI I I I I I= + = +% %

(3)

Where, Id is active and IQ is reactive a part of power. An AC and DC component is extracted by an occasional

pass filter. In this case:

l s cI I I= + (4)

In Eq. 4, Is is that the supply current, Il is that the load current and Ic is that the compensating current injected by

shunt electrical converter. If compensation reference currents area unit thought-about as follow:

* *,fd ld fq lqI I I I= =% %

(5)

In this case, the system`s currents are:

,s d ld s q lqI I I I= = (6)

In the Eq. 6, simply the load current harmonics area unit remunerated. If power issue is taken into account too, the

reference currents would be as follow:



* *,fd ld fq lqI I I I= =%

(7)

Then system currents are:

, 0s d lq s qI I I= = (8)

* *,cd ld dc cq lqI I i I I= + =% (9)

Static Shunt Compensator Using ANN

In Figure 5 the fast current of the nonlinear load is expanded into three terms. The primary term is that the load

functions sent from PLL (Phase latched Loop) in accordance with equation.(3)

0

0d q

L d q a b c L a b cI T i= (10)

By this remodel, the basic positive sequence parts area unit remodeled into dc Quantities in d and letter of the

alphabet axes, which may simply be extracted by low-pass, filter (LPF).

Figure 5: Control of the Shunt Converter of the Nine Switch UPQC Using ANN

All harmonic parts area unit remodeled into ac quantities with a harmonic shift

Lq LqLqI i i= +%% (11)

Since L s ci i i= + (12)

Series Inverter Control Using PI

The duty of series electrical converter is compensating voltage distortions that are caused by fault in distribution

grid. Series electrical converter management calculates the voltage reference values, that are injected to grid by series

electrical converter.



Figure 6: Control Block Diagram of Series Inverter Using PI

In order to regulate series electrical converter of UPQC, load curving voltage dominant strategy is projected.

During this condition, UPQC series electrical converter would be controlled during a approach that it compensates the total

distortions and helps the voltage of load voltage keep (balanced curving 3-phase). so as to succeed in this aim, synchronous

frame of reference theory is applied (11).

* 0 *0 . 0

0

mdq

ldq abc labc

V

V T V

= = (13)

( )( )( )

*

cos

cos 120

cos 120

m

labc m

m

V t

V V t

V t

ω θω θω θ

+ = + − ° + + ° (14)

* *0 0 0fdq ldq sdqV V V= −

(15)

Series Inverter Control Using ANN

The system aspect voltage might contain negative-zero-sequence still as harmonics parts which require to be

eliminated by the series compensator. The management of the series compensator is shown in Figure 7. The system

voltages are detected then reworked into synchronous dq-0 frame of reference exploitation equation (6).

Figure 7: Control Block Diagram of the Series Converter of the UPQC Using ANN



ARTIFICIAL NEURAL NETWORK

Neural networks are simplified models of the biological nervous systems. An NN can be defined as a data

processing system. Consisting of a large number of simple, highly interconnected processing elements (artificial neurons),

in an architecture inspired by the structure of the cerebral cortex of the brain.

An artificial neuron receives n inputs x1, x2…xn with weights w1, w2 ….wn attached to the input links.

The weighted sum of the inputs ( )Iφ .i iw x∑ is computed to be passed on to a nonlinear filter φ called activation

function to release the output( )Iφ . Here, φ could be a step function, signum function, sigmoid function or hyperbolic

tangent function.

Neural networks are models of biological neural structures. The place to begin for many neural networks is a

model nerve cell (neuron).This nerve cell consists of multiple inputs and one output. Every input is changed by a weight

that multiplies with the input worth. The nerve cell can mix these weighted inputs and, with relevance a threshold worth

and activation operate, use these to work out its output. This behavior follows closely our understanding of however real

neurons work.

Figure 8: Model of Neural

While there is a good understanding of however a private somatic cell(neuron) works, there is still a good deal of

research and largely conjecture concerning the approach neurons organize themselves and therefore the mechanisms used

by arrays of neurons to adapt their behavior to external stimuli. There are an outsized variety of experimental neural

network structures presently in uses reflective this state of continuous analysis.

In our case, we will solely describe the structure, arithmetic and behavior of that structure referred to as the back

propagation network. This can be the foremost current and generalized neural network presently in use.

To build a back propagation network, proceed within the following fashion. First, take variety of neurons and

array them to create a layer. A layer has all its inputs connected to either a preceding layer or the inputs from the external

world, however not each at intervals a similar layer.

A layer has all its outputs connected to either a succeeding layer or the outputs to the external world, but not each

at intervals a similar layer. Next, multiple layers square measure then clad one succeeding the opposite in order that there\'s

Associate in Nursing input layer, multiple intermediate layers and at last Associate in Nursing output layer, as in Figure



three. Intermediate layers that are people who don‘t have any inputs or outputs to the external world, are referred to as

hidden layers. Back propagation neural networks are sometimes totally connected. This implies that every vegetative

cell(neuron) is connected to each output from the preceding layer or one input from the external world if the vegetative cell

is within the initial layer and, correspondingly, every vegetative cell has its output connected to each vegetative cell within

the succeeding layer.

Figure 9: Back Propagation Network

Generally, the input layer is taken into account a distributor of the signals from the external world. Hidden layers

square measure thought of to be categorizers or feature detectors of such signals.

( )j th j jY F U t= + ……… (16)

The output layer is taken into account a collector of the options detected and producer of the response. While this

read of the neural network could also be useful in conceptualizing the functions of the layers, you should not take this

model too virtually because the functions delineate might not be thus specific or localized.

FUZZY LOGIC CONTROLLER

The inherent characteristics of the changing loads, complexity and multi-variable conditions of the power system

limits the conventional control methods giving satisfactory solutions. Artificial intelligence based gain scheduling is an

alternative technique commonly used in designing controllers for non-linear systems. Fuzzy system transforms a human

knowledge into mathematical formula. Therefore, fuzzy set theory based approach has emerged as a complement tool to

mathematical approaches for solving power system problems. Fuzzy set theory and fuzzy logic establish the rules of a

nonlinear mapping. Fuzzy control is based on a logical system called fuzzy logic which is much closer in spirit to human

thinking and natural language than classical logical systems. Nowadays fuzzy logic is used in almost all sectors of industry

and science. One of them is using fuzzy logic controller with UPQC.

The main goal of UPQC in interconnected power systems is to enhance the power quality of the system. The

balance between production and consumption Control algorithms supported fuzzy logic are enforced in several processes.

The appliance control techniques has been motivated by the subsequent reasons: 1) Improved strength over the traditional

linear management algorithms; 2) Simplified control design for difficult system models; 3) Simplified implementation



Low –frequency oscillations are a common problem in large power systems. A power system stabilizer (PSS) can

provide a supplementary control signal to the excitation system and/or the speed governor system of the electric generating

unit to damp these oscillations. Due to their flexibility, easy implementation, and low cost, PSSs have been extensively

studied and successfully used in power systems for many years.

Most PSSs in use in electric power systems employ the classical linear control theory approach based on a linear

model of a fixed configuration of the power system. To improve the performance of UPQC, numerous techniques have

been proposed for their design, such us using intelligent optimization methods (genetic algorithms, neural networks, fuzzy

and many other nonlinear control techniques). It recent years, fuzzy logic Management has emerged as a robust tool and is

beginning to be utilized in numerous grid applications.

The application of fuzzy logic control techniques appears to be most suitable one whenever a well-defined control

objective cannot specified, the system to be controlled is a complex one, or its exact mathematical model is not available.

Recent analysis indicates that a lot of stress has been placed on the combined usage of fuzzy systems and neural networks.

The fuzzy logic controller designed can be of the form shown in Figure 2.

Figure 10: Fuzzy Logic Controller

The fuzzy logic controller is comprised of four main components: the fuzzification, the inference engine, the rule

base, and the defuzzification, as shown in Figure 3.

Figure 11: Components of Fuzzy Controller

The fuzzifier transforms the numeric/crisp value into fuzzy sets; therefore this operation is called fuzzification.

The main component of the fuzzy logic controller is the inference engine, which performs all logic manipulations in a

fuzzy logic controller. The rule base consists of membership functions and control rules. Lastly, the results of the inference

process is an output represented by a fuzzy set, however, the output of the fuzzy logic controller should be a numeric/crisp

value. Therefore, fuzzy set is transformed into a numeric value by using the defuzzifier. This operation is called

defuzzification.



SIMULATION CIRCUITS

Figure 12: Block Diagram of Nine Switch UPQC

Figure 13: Block Diagram of Nine Switch UPQC with PI Controller



Figure 14: Block Diagram of Nine Switch UPQC With ANN Controller

Figure 15: Block Diagram of Nine Switch UPQC with FUZZY Logic Controller

SIMULATION RESULTS

Figure 16: PI Controller with SAG Condition at Load Voltage, Input Voltage, and Injected Voltage



Figure 17: PI Controller with SAG Condition at Load Current, Input Current, and Injected Current

Figure 18: PI Controller with SWELL Condition at Lo ad Voltage, Input Voltage, and Injected Voltage

Figure 19: PI Controller with SWELL Condition at Lo ad Current, Input Current, and Injected Current

Figure 20: ANN Controller with SAG & SWELL Conditio n at Load Voltage, Input Voltage, and Injected Voltage



Figure 21: ANN Controller with SAG & SWELL Conditio n at Load Current, Input Current, and Injected Curr ent

Figure 22: FUZZY Logic Controller with SAG & SWELL Condition at Load Voltage, Input Voltage, and Injected Voltage

Figure 23: FUZZY Logic Controller with SAG & SWELL Condition at Load Current, Input Current, and Injected Current

Figure 24: Utility Side Voltage THD with ANN 1.36% at 3rd Harmonic Order



RESULT TABLE

Table 1

CONCLUSIONS

The UPQC performance principally depends upon however accurately and quickly reference signals are derived.

The simulated result shows that it has considerable response time for yielding effective compensation in the network.

This may not be desirable in modern power system control. Using conventional compensator data, a fuzzy logic controller

(FLC) is tuned with large number of data points. Then conventional compensator was replaced with fuzzy logic controller

and ANN.

The simulation results have shown that the UPQC perform higher with ANN and FLC planned theme

eliminates each voltage similarly as current harmonics effectively. The ANN controller also performs in a similarly with

slightly better voltage compensation It is also observed that the response time for derivation of compensation signals

reduces significantly with improved accuracy.

The response of FUZZY & ANN controllers are THD is minimum and faster for the both the current and voltage

which is evident from the plots comparison compared with PI controller as shown Result Table. Proposed model for the

Nine Switch UPQC is to compensate input current harmonics and voltage harmonics caused by non-linear load. The work

can be extended to compensate the load current and supply voltage imperfections such as swells, sags, voltage imbalance,

current unbalance, interruptions, and flicker.

REFERENCES

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AUTHOR’S PROFILE

Mr. SHAIK. MABUSUBANI is a student of Sri Mittapalli College of Engineering, Guntur, AP. Currently he is

pursuing M. Tech in Power Electronics and Electrical Drives (12U91D5408) from S.M.C.E. He completed B. Tech

(E.E.E.) in Chalapati Institute of Technology. His area of interests include Power Quality by Custom Power Devices,

controllers like Conventional controllers, Artificial intelligence controlling techniques, power Electronics & Drives, Neuro

controller Neuro-fuzzy controllers, renewable energy resources, Fuzzy logic controllers.

Mr. SURESH. KORNEPATI presently working as Associate Professor & Head, Deportment of EEE in Sri

Mittapalli College of Engineering, Guntur, A. P. He having 12 years of Experience in Teaching. Currently he is pursuing

PhD in Andhra University. His area of interests include renewable energy resources, Power Quality by custom Power

Devices, Power System Operation, Control & Stability, Intelligent controlling techniques and Power Electronics & Drives.