IRJET- Reducing Harmonics in Micro Grid Distrubution System using APF with PI Controller

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 05 Issue: 12 | Dec 2018 www.irjet.net p-ISSN: 2395-0072
© 2018, IRJET | Impact Factor value: 7.211 | ISO 9001:2008 Certified Journal | Page 345
REDUCING HARMONICS IN MICRO GRID DISTRUBUTION SYSTEM USING
APF WITH PI CONTROLLER
KADIKUNTA NAVEEN KUMAR1, J. MURALI KRISHNA2, P. NAGENDRA3, M. RAVI KUMAR4
--------------------------------------------------------------------***---------------------------------------------------------------------
ABSTRACT:- In distribution systems, the load has been a
sudden increase or decreases and it is like as nonlinear
loads so the load draws non-sinusoidal currents from the
AC mains and causes the load harmonics and reactive
power, and excessive neutral currents that give pollution
in power systems. Most pollution problems created in
power systems are due to the nonlinear characteristics
and fast switching of power electronic devices. Shunt
active filter based on current controlled PWM converters
are seen as a most viable solution. This report presents the
harmonics and reactive power compensation from 3P4W
micro-grid distribution system by IP controlled shunt
active. The technique which is used for generate desired
compensation current extraction based on offset
command instantaneous currents distorted or voltage
signals in the time domain because compensation time
domain response is quick, easy implementation and lower
computational load compared to the frequency domain.
1. INTRODUCTION
Renewable generation affects power quality due
to its nonlinearity, since solar generation plants and
wind power generators must be connected to the grid
through high-power static PWM converters. The non
uniform nature of power generation directly affects
voltage regulation and creates voltage distortion in
power systems. This new scenario in power distribution
systems will require more sophisticated compensation
techniques.
Although active power filters implemented with
three-phase four-leg voltage-source inverters (4L-VSI)
have already been presented in the technical literature,
the primary contribution of this report is a predictive
control algorithm designed and implemented specifically
for this application.
2. PHOTOVOLTAIC TECHNOLOGY
Photovoltaic's is the field of technology and research
identified with the devices which directly convert
sunlight into power utilizing semiconductors that exhibit
the photovoltaic impact. Photovoltaic impact includes
the making of voltage in a material upon presentation to
electromagnetic radiation. The photovoltaic impact was
first noted by a French physicist, Edmund Becquerel, in
1839, who discovered that specific materials would
create little measures of electric current when presented
to light. In 1905, Albert Einstein depicted the idea of light
and the photoelectric impact on which photovoltaic
technology is based, for which he later won a Nobel prize
in physics. During the 1960s, the space business started
to make the primary genuine utilization of the
technology to give power on board rocket. Through the
space programs, the technology propelled, its
unwavering quality was established, and the cost started
to decay. Amid the vitality emergency during the 1970s,
photovoltaic technology gained acknowledgment as a
source of power for non-space applications.
The solar cell is the rudimentary building square
of the photovoltaic technology. Solar cells are made of
semiconductor materials, such as silicon. One of the
properties of semiconductors that makes them most
helpful is that their conductivity may effectively be
adjusted by bringing debasements into their precious
stone grid. For example, in the manufacture of a
photovoltaic solar cell, silicon, which has four valence
electrons, is blessed to receive increment its
conductivity. On one side of the cell, the contaminations,
which are phosphorus iotas with five valence electrons
(n-contributor), give feebly bound valence electrons to
the silicon material, making abundance negative charge
carriers.
On the other side, molecules of boron with three
valence electrons (p-benefactor) make a more
prominent fondness than silicon to pull in electrons.
Since the p-type silicon is in personal contact with the
type silicon a p-n junction is established and a
dissemination of electrons happens from the district of
high electron concentration (the n-type side) into the
area of low electron concentration (p-type side). When
the electrons diffuse over the p-n junction, they
recombine with holes on the p-type side.
However, the dispersion of carriers does not
happen inconclusively, in light of the fact that the
unevenness of charge instantly on either sides of the
junction begins an electric field. This electric field shapes
a diode that elevates current to stream in just a single
direction.
.

Fig 1 SOLAR CELL
Ohmic metal-semiconductor contacts are made
to both the n-type and p-type sides of the solar cell, and
the cathodes are prepared to be associated with an
outside load. When photons of light fall on the cell, they
exchange their vitality to the charge carriers. The electric
field over the junction isolates photo-generated positive
charge carriers (holes) from their negative partner
(electrons). In this way an electrical current is extricated
once the circuit is shut on an outside load
The photovoltaic impact was first announced by
Edmund Becquerel in 1839 when he seen that the
activity of light on a silver covered platinum terminal
submerged in electrolyte delivered an electric current.
After forty years the primary strong state photovoltaic
devices were built by specialists researching the as of
late found photoconductivity of selenium. In 1876
William Adams and Richard Day discovered that a
photocurrent could be created in an example of selenium
when reached by two heated platinum contacts. The
photovoltaic activity of the selenium varied from its
photoconductive activity in that a current was created
suddenly by the activity of light.
3. INVERTERS
The fundamental goal of static power converters
is to deliver an air conditioner output waveform from a
dc power supply. These are the kinds of waveforms
required in customizable speed drives (ASDs),
uninterruptible power supplies (UPS), static var
compensators, active filters, adaptable air conditioning
transmission systems (FACTS), and voltage
compensators, which are just a couple of uses. For
sinusoidal air conditioning outputs, the size, frequency,
and phase should be controllable. As per the kind of air
conditioning output waveform, these topologies can be
considered as voltage source inverters (VSIs), where the
autonomously controlled air conditioning output is a
voltage waveform.
These structures are the most generally utilized
in light of the fact that they normally behave as voltage
sources as required by numerous modern applications,
such as customizable speed drives (ASDs), which are the
most well known utilization of inverters; see Fig. 6.1. So
also, these topologies can be found as current source
inverters (CSIs), where the freely controlled air
conditioning output is a current waveform. These
structures are still generally utilized in medium-voltage
modern applications, where high-quality voltage
waveforms are required.
Static power converters, particularly inverters,
are built from power switches and the air conditioner
output waveforms are therefore comprised of discrete
values. This prompts the generation of waveforms that
highlight quick changes rather than smooth ones. For
example, the air conditioner output voltage delivered by
the VSI of a standard ASD is a three-level
Fig: 2 Adujustable speed drive
Basic designs:
In one simple inverter circuit, DC power is
connected to a transformer through the centre tap of the
primary winding. A switch is rapidly switched back and
forth to allow current to flow back to the DC source
following two alternate paths through one end of the
primary winding and then the other. The alternation of
the direction of current in the primary winding of the
transformer produces alternating current (AC) in the
secondary circuit.
The electromechanical version of the switching
device includes two stationary contacts and a spring
supported moving contact. The spring holds the movable
contact against one of the stationary contacts and an
electromagnet pulls the movable contact to the opposite
stationary contact. The current in the electromagnet is
interrupted by the action of the switch so that the switch
continually switches rapidly back and forth. This type of
electromechanical inverter switch, called a vibrator or
buzzer, was once used in vacuum tube automobile
radios. A similar mechanism has been used in door bells,
buzzers and tattoo. As they became available with
adequate power ratings, transistors and various other

types of semiconductor switches have been incorporated
into inverter circuit designs.
Output waveforms:
The switch in the straightforward inverter
portrayed above, when not coupled to an output
transformer, delivers a square voltage waveform
because of its basic now and again nature instead of the
sinusoidal waveform that is the typical waveform of an
AC power supply. Utilizing Fourier examination,
occasional waveforms are spoken to as the entirety of an
unbounded series of sine waves. The sine wave that has
indistinguishable frequency from the first waveform is
known as the basic segment. The other sine waves,
considered harmonics that are incorporated into the
series have frequencies that are essential multiples of
the central frequency.
The quality of the inverter output waveform can
be communicated by utilizing the Fourier investigation
information to ascertain the aggregate harmonic
distortion (THD). The aggregate harmonic distortion is
the square base of the total of the squares of the
harmonic voltages separated by the basic voltage:
Fig 3 Fundamental and harmonic wave form
TYPES OF INVERTERS:
Generally inverters are of Two Types:
1. VOLTAGE SOURCE INVERTER
2. CURRENT SOURCE INVERTER
4. FOUR-LEG CONVERTER MODEL
Fig. 4 shows the configuration of a run of the
mill power distribution system with inexhaustible power
generation. It comprises of different kinds of power
generation units and distinctive sorts of loads.
Inexhaustible sources, such as wind and sunlight, are
ordinarily used to generate power for private clients and
little enterprises. Both sorts of power generation utilize
air conditioning/air conditioning and dc/air
conditioning static PWM converters for voltage change
and battery banks for long haul vitality stockpiling.
These converters perform most extreme power direct
following toward concentrate the greatest vitality
conceivable from wind and sun. The electrical vitality
utilization behavior is random and eccentric, and
therefore, it might be single-or three-phase, adjusted or
unequal, and straight or nonlinear. An active power filter
is associated in parallel at the purpose of common
coupling to remunerate current harmonics, current
unbalance, and reactive power. It is formed by an
electrolytic capacitor, a four-leg PWM converter, and a
first-arrange output ripple filter, as shown in Fig. 1.2.
This circuit considers the power system proportionate
impedance Zs, the converter output ripple filter
impedance Zf , and the load impedance ZL .
Fig. 4 Two-level four-leg PWM-VSI topology.
The four-leg PWM converter topology is shown
in Fig. 5.1. This converter topology is like the
conventional three-phase converter with the fourth leg
associated with the impartial bus of the system. The
fourth leg expands switching states from 8 (23) to 16
(24), enhancing control adaptability and output voltage

quality, and is reasonable for The voltage in any leg x of
the converter, measured from the neutral point (n), can
be expressed in terms of switching states, as follows:
The mathematical model of the filter derived
from the equivalent circuit shown in Fig.5. 2 is
where Req and Leq are the 4L-VSI output
parameters communicated as Thevenin impedances at
the converter output terminals Zeq. Therefore, the
Thevenin proportional impedance is dictated by a series
association of the ripple filter impedance Zf and a
parallel course of action between the system equal
impedance Zs and the load impedance ZL
For this model, it is expected that ZL »Zs, that
the resistive piece of the system's comparable
impedance is ignored, and that the series reactance is in
the scope of 3– 7% p.u., which is a satisfactory guess of
the genuine system. At long last, in (2) Req = Rf and Leq
= Ls + Lf.
5. SIMULATION RESULTS
A reenactment model for the three-phase four-
leg PWM converter with the parameters shown in Table I
has been produced utilizing MATLAB-Simulink. The goal
is to check the current harmonic compensation viability
of the proposed control scheme under various working
conditions. A six-pulse rectifier was utilized as a
nonlinear load. The proposed prescient control
algorithm was modified utilizing a S-work obstruct that
permits recreation of a discrete model that can be
effectively actualized in a continuous interface (RTI) on
the dSPACE DS1103 R&D control board. Reproductions
were performed considering a 20 [μs] of test time.
In the recreated results shown in Fig. 6.2, the
active filter starts to remunerate at t = t1. Right now, the
active power filter infuses an output current iou to repay
current harmonic parts, current lopsided, and unbiased
current all the while. Amid compensation, the system
currents is show sinusoidal waveform, with low
aggregate harmonic distortion (THD = 3.93%). At t = t2,
a three-phase adjusted load step change is generated
from 0.6 to 1.0 p.u. The remunerated system currents
stay sinusoidal regardless of the change in the load
current extent. At long last, at t = t3, a single-phase load
step change is presented in phase u from 1.0 to 1.3 p.u.,
which is equal to a 11% current unevenness. Not
surprisingly on the load side, an unbiased current
courses through the nonpartisan conductor (iLn),
however on the source side, no impartial current is
watched (isn). Recreated results show that the proposed
control scheme viably kills uneven currents. Also, Fig. 8
shows that the dc-voltage stays stable throughout the
whole active power filter operation.
Fig.5 APF Control scheme
Fig. 6. APF load voltage, current, filter output
current, load neutral current

Fig. 7 Non linear Voltage
Fig. 8. Source voltage, Load current, Filter output
currents, load neutral current, system neutral
current, system currents, dclink voltage
6. CONCLUSION
Enhanced unique current harmonics and a
reactive power compensation scheme for power
distribution systems with generation from sustainable
sources has been proposed to enhance the current
quality of the distribution system. Favorable
circumstances of the proposed scheme are identified
with its straightforwardness, modeling, and usage. The
utilization of a prescient control algorithm for the
converter current loop turned out to be a successful
answer for active power filter applications, enhancing
current following ability, and transient reaction.
Reproduced and experimental results have
demonstrated that the proposed prescient control
algorithm is a decent option in contrast to traditional
direct control methods. The prescient current control
algorithm is a steady and robust arrangement.
Reenacted and experimental results have shown the
compensation viability of the proposed active power
filter.
FUTURE SCOPE
Power systems are developed from remote
generators feed their loads to huge interconnected
systems which are spread crosswise over numerous the
nation. Interconnected systems are more dependable
systems, since if there should be an occurrence of
disruption in various parts like one a player in the
system; power can spill out of substitute paths and thus
can keep up coherence of the system. Though, harmonic
distortions which are presented by the nonlinear loads
will engender throughout. These issue might be
fathomed by introducing specific sorts of filters of
appropriately structured appraisals, best case scenario
conceivable areas in the interconnected power system.
The ideal assignment and rating of these shunt active
filters can be resolved with help of developmental
algorithms.
Supportable extension in the power system it is
important to make utilization of the sustainable power
source resources like Wind, Biomass, Hydal power, Co-
generation, and so forth. The expansion of sustainable
power source into the realistic power system
additionally generates and influences power quality
gives such as sudden voltage homeless people,
precariousness, and so forth. Induction generator is
helpful as wind power generator; it requires reactive
power for charge. When the generated active power
generated by APF of an induction generator is differed
because of wind speed, the assimilated reactive powers
and terminal voltages of an induction generator are
hugely influenced. An appropriate controlled scheme in
wind vitality generation system is fundamental under
the typical working condition to let permit the right
control over the active power creation. By and large
Shunt Active Hybrid Filters are recommended for better
enhancing of power quality issues, when generation
quickly changes with wind speed.
REFERENCES
[1] D. D. Sabin and A. Sundaram, “Quality enhances
reliability,” IEEE Spectr., vol. 33, no. 2, pp. 34–41,
Feb. 1996.
[2] M. Rastogi, R. Naik, and N. Mohan, “A comparative
evaluation of harmonic reduction techniques in
three-phase utility interface of power electronic
loads,” IEEE Trans. Ind. Appl., vol. 30, no. 5, pp.
1149–1155, Sep./Oct. 1994.

[3] F. Z. Peng, “Application issues of active power
filters,” IEEE Ind. Appl. Mag., vol. 4, no. 5, pp. 21–30,
Sep../Oct. 1998.
AUTHORS:
1. KADIKUNTA NAVEEN KUMAR,
MASTER OF TECHNOLOGY in POWER ELECTRONICS
to the Jawaharlal Nehru technological university
2. J. MURALI KRISHNA,
Assistant Professor, Department of EEE.
3. P. NAGENDRA,
4. M. RAVI KUMAR.

IRJET- Reducing Harmonics in Micro Grid Distrubution System using APF with PI Controller

More Related Content

What's hot (20)

Similar to IRJET- Reducing Harmonics in Micro Grid Distrubution System using APF with PI Controller (20)

More from IRJET Journal (20)

Recently uploaded (20)

IRJET- Reducing Harmonics in Micro Grid Distrubution System using APF with PI Controller