A project Report on
Grid connected Photo-voltaic active power filter
By
Mote Mahesh
(19891D5403)
Under guidance of
G. Srikanth
Assistant professor
Dr. D. Suresh
Assistant professor
Department of Electrical and Electronics Engineering
Vignan institute of technology and science, Deshmukhi
CONTENTS
CHAPTER 1:
CHAPTER 2:
CHAPTER 3:
Chapter 4:
REFERENCES
CHAPTER I
INTRODUCTION
1. Introduction
Normally the sources of harmonics are divided into four categories. [1-3] [4] as shown in the
table I.
Table I. Source of harmonics
Power electronics converters
Arcing equipment
Saturable
devices
Adjustable speed drives
Arc
furnaces Transformers
Uninterruptable power supplies
Induction
motors
switch mode power supplies
furnaces welders
Generators etc.
static
converters
thyristor Lighting etc.
converter systems,
diode bridges induction furnaces
based power electronics etc.
Control devices
static
VAR
compensators,
power
factor
correction capacitors
The increased use of power semiconductor devices in wide variety of loads has given
birth to numerous power quality problems in the electric power networks. These power quality
problems (pq) such as voltage regulation, power factor deviation, harmonics and current
unbalance etc. Threats posed by these power quality problems are being mitigated by installing
filters in shunt with nonlinear loads [3]. Earlier, passive filters were in use, but owing to
drawbacks pretense by them viz. large size, resonance and fixed compensation [9], the focus of
power engineers has shifted towards APFS. APFS are capable enough to provide the solution
related to harmonic compensation, reactive power compensation, balancing three-phase line
currents, damping of oscillation in currents and voltage regulation. Since, shunt APFS are
connected in parallel with the load, and thus, they do not burden the source on account of
displacement power factor and loading.
The accuracy and fast response of active power filter controller depend upon the proper
estimation of reference current, both in quality and configuration. Various control algorithms are
reported in literature [3, 4, 5-13]. Many of them were time relevant. Most of the algorithms
reported in literature need two axis transformations, and hence, augment the complexities in their
implementation. Some direct and indirect controls of APF are also reported in the literature [3,
5]. However, the rising uncertainties in ac electrical system and increasing dynamics and
nonlinearity of loads have attracted more attention of engineers/researchers to evolve improved
methods. This leads to evolution of universal control technique of compensation having
substantially improved transient performance balanced/under unbalanced load conditions. In
addition to above, in most of the industrial environment the distortion in utility voltage is
escalating at a very fast rate. It is experienced that the performance of active power filter has
deteriorated under distorted supply voltage conditions [1]. Under distorted supply voltage, the
harmonics are generated in the load current despite the linear load. Among these the sum of all
frequency components of utility harmonic current is defined as total conforming current, which
have similar shape as that of the voltage due to same relative level of harmonics. It is the current
that the customer should be allowed to draw from a non-sinusoidal supply voltage network. On
the other hand, the sum of frequency components of customer generated harmonic current is the
harmonic current, which is generated by the customer and should be compensated by active
power filter [12].
As a consequence, firstly, there is a need to develop a method which attributes the
responsibilities of the customer and utility at the point of common coupling. Secondly, there is a
need to develop controller for active power filter that works properly and compensates generated
harmonics from the nonlinear load.
1.1. Active power filter
The active power filter is prime device, which will maintain the grid voltage and current in
sinusoidal by supplying reactive power or drawing reactive power. The power electronics based
converter used for transmission voltage termed as static compensator. Now days active power
filter application has been extended to the distribution level and converter used at distribution
voltage level termed as distributed static compensator.
1.1.1. Basic Compensation Principle of active power filter
Active power filter consists of three parts
1. Measuring devices
2. Power inverter circuit
3. Active power filter controller
The inverter circuit used to draw the compensating current from power supply. The
compensating current is drawn from power supply in phase opposition with the load current.
Therefore, inverter is responsible for compensating current. The active power filter controller is
used for control scheme implementation and generation of gate pulses for switching devices of
the inverter. These switching pulses continuously supplied to the gate driver of switching
devices. The active power filter power circuit diagram is shown in Fig.9. A voltage source
inverter with necessary passive components is used as an active power filter and is connected in
parallel at the point-of-common coupling (PCC).
VSa
iSa
iLa
Lac
VSb
iSb
iLb
Lac
VSc
iSc
iLc
Lac
Threephase,
Three-wire
Non-linear
Load
iCa iCb iCc
Lc
Cdc
Figure 1. Topology Of active power filter
The compensation characteristics of active power filter are shown in the Fig. 10. The current IL
represents the load current, waveform IC represents the compensation current injected by the
active power filter, waveforms VS represents the voltage waveform and IS represent the source
current. The active power filter control scheme is implemented on the processor to generate the
firing pulses and passed to the switching device.
Fig. 2.Basic compensation principle of APF.
The firing pulses are passed to active power filter to draw the compensating current IC from the
ac power supply. The active power filter is inject the compensating current to cancels the
reactive and harmonic current contained in the load current IL. After compensation with active
power filter the source current (IS) is sinusoidal and in synchronous with its respective source
voltage waveform (VS).
1.1.2. Solution methodologies
Many harmonic mitigation devices, like passive filter, active filter and distribution static
compensator, have been designed and installed in power networks to improve the quality of
power. For appropriate design and optimal placement of these harmonic mitigation devices,
analysis of harmonic is essential. Harmonics analysis is basically the process of calculating the
magnitude and phases of the fundamental and higher order harmonics of a given periodic wave.
The resulting series, known as Fourier series, establishes a relation between the time domain and
frequency domain of a given function. The complete power system harmonic study can be
described by the different techniques for harmonic analysis, identification of harmonic sources,
monitoring of harmonics and their mitigation methods.
From the literature review, it is apparent that a lot of work has been carried out in the area of
harmonic power flow studies. Different algorithms for carrying out harmonic analysis have been
proposed in the literature, with some of them even being commercialized. Due to continuous
advancement in technology and invention of newer power electronic devices for a more efficient
operation, nature of harmonics generated by the loads is also changing. In this changing
behavioral environment of loads, it is necessary to update the power system planners and
operators with recent harmonic trends, nature and patterns. Thus, there is still a need for regular
harmonic measurements and analysis, so that one can identify the causes and effects, and take
appropriate remedial action accordingly.
In this work, instantaneous reactive power theory has been used for the active power filter to
estimate reference current. The active power filter with IRPT method eliminates harmonics of
nonlinear load.
Chapter II
Grid connected neutral point clamped inverter based Photo-voltaic active power filter
Abstract: In this paper, the diode bridge rectifier based the grid integrated active neutral point
clamped converter based APF presented for elimination of harmonics caused by the nonlinear
load and injection of active power harvested from photo-voltaic arrays. It is well-known
multilevel converters can possess great advantages such as low switching losses and reduced size
of filter requirement. The instantaneous reactive power theory based reference current estimation
is presented with maximum power point (MPPT) tracking. The MPPT algorithm based on
perturb and observe is integrated with instantaneous reactive power theory. The simulated
response of the NPC based APF is show effective for injecting active power from photo voltaic
system.
2.1. INTRODUCTION
The increased use of power semiconductor devices in wide variety of loads has given birth to
numerous power quality problems in the electric power networks. These power quality problems,
their causes and effects on the power system components are explicated in this chapter. Threats
posed by these power quality problems are being mitigated by installing APF in shunt with
nonlinear loads. Earlier, passive filters were in use, but owing to drawbacks pretense by them
viz. large size, resonance and fixed compensation, the focus of power quality engineers has
shifted towards APF. APFs are capable enough to provide the solution related to harmonic
compensation, reactive power compensation, balancing three-phase line currents, damping of
oscillation in currents and voltage regulation. Since, APFs are connected in parallel with the load
and thus, they do not burden the source on account of displacement power factor and extra
loading effect.
The most of the APFs are based on shunt coupled active power filter, which is used for
compensation of harmonics and volatile power of the nonlinear load. The family of APFs
referred with single name that is custom power devices. The custom power devices are APF,
dynamic voltage restorer and compensator of integrated power quality etc. The APF is
multifunctional device which provide the harmonics elimination, reactive power compensation,
voltage regulation, power factor correction, load balancing and termination of the line.
The execution of the APF to a great extent relies upon the ongoing estimation of the
remuneration current. The most usually utilized strategies in literature are instantaneous and
synchronous theory-based detection of the compensation current. Because of its ease of
calculation of harmonics currents and self-learning ability, adaptive control scheme gain
attention in the estimation of reference currents [13]. In this chapter, IRPT algorithm is arrived
for harmonics current estimation.
Now a day, the grid integration of renewable energy based generation is increasing with
improved power quality feature such as harmonics elimination, reactive power compensation and
load balancing. In recent studies the two and three level inverters are compared based on
semiconductor losses and filter consideration and evaluated that three level inverter possess
lower semiconductor losses for higher switching frequencies than the two level counterparts
because three level inverters have only one device commutate at each transition. In addition to
that, ac output waveform of a multilevel inverter possess a lower harmonic and reduced sizes of
the ac filter components are possible[1]-[4].
2. 2. Diode bridge rectifier based battery charger
2.3. CONFIGURATION OF APF TOPOLOGY
The APF configuration based on diode clamped multilevel inverter is shown in the Fig. 3.1. The
DCMLI seems to be most suitable inverter topology for photo-voltaic application without
separate inverter. The DCMLI inverter has common dc bus for easy integration of photovoltaic
cell. The overall power circuit of APF consist of PV array on dc side, DCMLI inverter,
interfacing inductor and dc link capacitor. The interfacing inductor used to suppress the
switching high frequency harmonics. The APF connected at point of common coupling through
interfacing inductor.
Fig. 2. 1. Topology of PV cell integrated APF.
2.3. : Instantaneous reactive power theory
IRPT theory (p-q or IRP theory) depends on the set of instant power defined in the time domain
[2]. The IRPT can be used for four wire system with modification.
Given system terminal voltages
vSa d  vm dcost 
2

v  v cos t 
Sbd
md

3

4

v  v cos t 
Scd
md

3









(1)

The IRPT theory starts with three phase voltages and currents transforming into the αβ0
stationary reference frame. Clark Transformation In the immediate voltages in three-phase
instant voltages αβ0-axes vα, vβ and v0, in vSa, vSb, and vSc,

 1
 2
v0d
 

v


   2 1


 dd 
3 

v
0

1
2
1



 v 
 vSad 


 vSbd 
2   Sc 

3   d 
 
2 
1
2
1


2
3
2
(2)

Similarly, instant three-phase currents in the abc-phases, ica, icb, and icc are converted into the
instant two phase currents on the αβ0-axesiα, iβ, and i0 as,
i
0

i

i

d
d
d
 1

 2


2
 
1

3



0


1

2
1
2
3
2
1 
i 
2  ca
1   
  icb 
2   
i
3   cc 



2 
d
d
(3)
d

Since the 3P3W systems do not have a zero-sequence part, the v0and i0 can is eliminated in the
equations and leads to the v0 of equation from the equation
v 
d
v  
  
d
1

1

2 
2

3 0
3


2
1  v 
2   Sad 
 v
3   Sbd 



 v Sc  
2  d 
(4)

Similarly, the zero sequence components i0 also eliminated from the current quantities.
1

i 
1


2
 2 
  
 3
i 
3 0
 d


2
d


1  i 
2  cad 

 icb 
3




 i d 
2   ccd 
(5)
The instantaneous real power (p) and the instantaneous reactive power (q) are defined from
instantaneous phase voltages and load currents on the αβ0 axes as,
pd  vd id  v di d
(6)
qd  v d i d  v di d
(7)
 pd   v
 qd 
 v d
 
 d
(8)
v  i 
vd  id 
d   d 


Instant active and reactive forces P and Q can be classified as an average (DC) and a oscillating
(AC) quantities.

 pd   pd  pd 

 q   q  q 
 d  d
d 

(9)


The oscillation component of active power is eliminated with DSTATCOM. The oscillation part
of active power computed with low pass filter pd  pd  pd . In addition, DSTATCOM replaces
the reactive power q  q  q . It is computed from transformed signals. The DSTATCOM
compensation current estimated with IRPT scheme in are computed αβ0-reference frames as
follows
i* 
v
1
C d
2
 *   v2  v v d
i
C d 
  
 
d


d
d

v    p

d
 (q dq )
v   d
d 
d  
(10)
Due to negative signals in non-compensating powers, the compensation for producing the exact
opposite of the D-STATCOM or the undesirable powers drawn by reactive load is drawn.
Let the compulsory power (ploss) necessary to perform the dc bus voltage to its reference value.
As a result, the equation becomes
i* d 
vd
1
, iC*    2
2 v

 v  v  
d  d
d
C
 d


vd   pC  pLoss 
d
d


v  
q

Cd
d  

These quantities computed in o frame are transformed back to ABC quantities using inverse
Clarke’s transformation as,

(11)

 1
*
iCa
 
1
i*   2 
 Cb 
3  2
i* 
 Cc 
 1
  2



0 
i* 

3  iC
*


2  C 

3 
(12)
2 

The reference current computed with IRPT scheme is depicted in Fig.2.2.
Fig.2.1. Instantaneous reactive power theory.
2.4. Dynamics model of APF
The diode based dynamic model of photo-voltaic cell is shown in Fig.3.4. To obtain the required
level of power from photo voltaic cells, which are connected in series and parallel to form
modules and the modules are connected array to obtain higher voltage and current level.
Fig.2.2. Equivalent circuit of photovoltaic cell
The PV modules can be represented as approximate constant current source. The equation, which
is used to describing the I-V characteristic of a practical PV cell is
I  I I I
 I  I e qVoc    Vout  RS I
1
L
D 
Rsh
 CkT 


L
d
sh
(1)
Where I D the saturation is current, q is the electron charge 1.6 1019 C  , C is the diode
emission factor, k is the Boltzmann constant 1.381023 J/K and T is the temperature.
The power produced will be maximum at the knee point of the I-V characteristics of the PV
module and it is depicted in Fig.3. Voltage and current properties are consistent with the kneepoint of I-V. The maximum power can be obtained from PV modules with Maximum power
point tracking (MPPT) algorithm. The maximum point algorithm is attached with the APF
control scheme. The APF voltage is maintained with the MPPT algorithm at the correct value. In
this project, the incremental conductance method is used for tracking the maximum power from
PV modules [6]. This MPPT mechanism is the power line of the PV MPP point (where dv/dt=0),
on the left is positively, the opposite is negative. In the following equations, dv/di are a sample
delay values V
(2)
(3)
(4)
I
(0, ISC)
CURRENT SOURCE
VOLTAGE
SOURCE
(VSC, 0)
V
Fig.1. V-I characteristics of PV cell.
The DC voltage regulator with MPPT algorithm used for estimation of reference voltage is
shown in Fig.3. The reference DC voltage is estimated with incremental conductance method and
power generated from PV system also estimated for injecting active power from APF to grid. The
active power injected is carry negative sign, which shows that the APF inject active power into
the DG set feeding system.
3.4. DC link voltage regulation
3.5. Simulation results and discussion
The complete system of APF consists of the power source, DCMLI APF and nonlinear load.
Fig.2. Simulated waveform of APF.
Fig.3. Simulated waveform with MPPT.
When APF alone operating without photo voltaic modules connected on its dc side and it is used
for elimination of harmonics caused by the nonlinear load. Before t=0.05 sec., the source current
is consist of integer multiple triplen harmonics current. When APF is connected at t=0.05 sec.
source current tend to sinusoidal and in synchronous with voltage waveform. The source current
total harmonics distortion before compensation is 23.62% and its value after compensation is
found to be 2.04%.
Fig.4. Simulated waveform with power variation.
The simulated response of the DCMLI based APF is shown in Fig.4. Before compensation
with APF source current highly nonlinear and contains harmonics which is result in heating of
armature of the synchronous generator. When PV-APF start injecting active power harvested
from PV module, the source current tends to sinusoidal. The source current is in phase
opposition to source voltage, which shows the active power flow from PV-APF to the load. As
load demand increases on grid, PV-APF compensate the load current demand. This is in turn
results in reduction of fuel consumption. And also, APF compensate harmonics and balance the
current while feeding variety of the load.
The power variation with solar insolation is shown in the Fig.6. The different waveform of
spectrum identified as PV array voltage, PV array current and active power output of the PV
array. With increase in solar insolation, the quantity of output active power also increases. The
increase in power output from PV array the quantity of active power injected at point of common
coupling also increases. This increase in active power can be observed from the Fig.5, the value
of source current gradually increase with increase in compensating current of APF. The active
power injected from PV-APF relieves the loading on the DG set and also compensate the
harmonics and reactive power demand of the nonlinear load connected with DG set.
Fig.5. Source current THD without APF
Fig.6. Source current with APF compensation.
3.4. CONCLUSION
In this project, DCML Inverter is connected to PV APF and is connected to the elimination of
harmonics and reactive power compensation and active power injections. Instant reactive power
theory is connected with the MPPT controller. The algorithm is implemented based on the
incremental conductance method to obtain the maximum power from the PV array. The active
power control calculated from the PV range is used to introduce active power during joint coups
in combination. DCML Investor-based APF's simplest response shows the potential
compensation of active power injection from harmonics, reactive power and PV array.
Chapter III
Active neutral point clamped inverter based grid connected active power filter
In this chapter, diode rectifier based battery charger with active neutral point clamped inverter
(ANPCLI) based active power filter (APF) is presented. The active power filter with
instantaneous reactive power theory simultaneously eliminate harmonic current caused by load
and feed the active power to the source from photo-voltaic modules. The ANPC based active
offer various advantages such as equal distribution switching losses and reduced passive filter
size than that of neutral point clamped converter. The APF reference current tracked with IRPT
method. The IRPT method is combined with maximum power tracking algorithm to optimize the
active power fed to the grid. The incremental conductance based scheme is used as maximum
power point tracking algorithm. The reference estimated scheme is presented with maximum
power point tracking is used for simultaneous compensation of harmonics and active power
injection from the photo voltaic modules without requirement of the separate inverter power
circuit. The computer simulation study is carried out to test the efficacy of the control method for
simultaneous compensation of harmonics and active power injection from photovoltaic (PV)
modules. The PV-APF is used to relieve the source from excessive power demand from the
battery charger. The computer simulation study of system is carried to eliminate the harmonics
current caused by line frequency diode rectifier based battery charger.
3.1. INTRODUCTION
The power quality depends on the load characteristics and are varied with currents. As the load
become complex and sophisticated, current distortion become very costly for the manufacturers
in terms of loss of production, loss of raw materials and damage to the device.
In addition to
this, non-linear characteristics leads to many abnormalities such as voltage regulation, single
phasing and torque pulsation. This overall chapter is dedicated to the detailed computer
simulation study of the distributed static compensator as photo-voltaic grid connected APF with
ANPC based voltage source inverter connected in shunt with the electrical network. The first
part of the chapter describes the operating principle of a APF followed by control scheme used
for the reference current estimation. The second part presents the configurations of distributed
static compensator based on active neutral point clamped converter based three-level voltage
inverter. The third section is used to describe the photo-voltaic APF based on the active neutral
point clamped inverter. Finally, the last part is used to demonstrate the complete computer
simulation studies of APF as active power injection device and harmonics elimination without
any requirement of the separate inverter [1]-[4].
3.2. CONFIGURATION OF APF TOPOLOGY
The power circuit diagram is shown in the Figure1. The APF is connected in shunt with
load and the point of common coupling to eliminates the harmonics current and inject active
power of the photo-voltaic modules. The APF is connected at point of common coupling
through interfacing inductor. However, the size of the inductor depends on the switching
frequency. The dc link capacitor is connected on the dc side of the ANPC APF. The overall
system of the APF power system composed of source block, control of APF, voltage source
inverter and nonlinear load block. The control unit consists of the estimation of the harmonics
current and control of the current inject at the point of common coupling of electrical power
system of APF. The APF block consist of the interfacing inductor and dc link capacitor. The
non-linear load block consists of the bridge rectifier, commutation inductor and resistiveinductive load on the dc side of the bridge. The power circuit
VSa
ISa
VSb
ISb
VSc
ISc
iLa
ICa
iLb
ICb
iLc
ICc
Lc
Three-phase,
Three-wire
Non-linear
Load
Lc
Lc
Photovoltaic
modules
S1a
Vdc1
O
S1b
S2a
S2ac
S2bc
S2b
a
Photovoltaic
modules
S2bc
S2c
b
S2bc
S2ac
S1c
S1a’
S1b’
S2a’
S2b’
c
S2cc
S1c’
Vdc2
S2c’
Fig. 7. Topology of PV cell integrated APF.
3.3. CONTROL SCHEME of APF
The control scheme of PV-APF is given in section.2.2.
3.4. DC link voltage regulation
The outer loop used for voltage control with maximum power point tracking algorithm is shown
in Fig.4. The measured value of photo-voltaic voltage and current is used for the estimation of the
reference voltage. The estimated voltage with incremental conductance method is used for voltage
regulation across the dc link capacitors of the APF. The value of the reference estimated voltage
with maximum power point tracking is depends on the solar irradiations. Then the estimated
voltage is used to decide the active power injected into the grid. The active power injection is
carried out with the ANPC APF. In addition to this, the active power estimated with maximum
power point algorithm also substrated from the harmonics active power of control scheme. The
complete process used for the subsequent computations of the reference currents of the APF.
IP
VP
MAXIMUM POWER
POINT TRACKING
ALGORITHM
PI
controll
er
Fig. 8. DC voltage regulator
3.5. Simulation results and discussion
The complete power system blocks of the grid connected APF is built with
MATLAB/Simulink Simpower system block sets. The complete system of APF consists of the
source block, APF, control unit, and nonlinear load. The three source blocks of the APF block sets
are realized with MATLAB/Simulink Simpower system source block sets. The control unit of the
APF is realized with commonly used Simulink library and control blocks of MATLAB/Simulink
library. The APF and nonlinear load are realized with power electronics and elements of library of
MATLAB/Simulink.
Fig.9. Simulated waveform of APF.
Fig.10. APF Simulated waveform with MPPT.
The computer simulation with MATLAB/Simulink is shown in the Fig.5. The simulated
results of the APF is obtained before connection of photo-voltaic modules. When APF acting
alone without photo-voltaic modules then it eliminates the harmonics caused by the nonlinear
load. Initially, before the t=0.05sec., the source current is in stepped waveform and distorted. The
total harmonics distortion of source current is 23.7%. At the instant t=0.05 sec., when the firing
pulses are given to the APF switches then corresponding to it, APF injecting harmonics current
to eliminate the harmonics current caused by the non-linear load. The total harmonics distortion
of the source current before harmonics elimination is shown in the Fig.8. After the harmonics
current elimination with APF the total harmonics distortion is 2.7% and corresponding total
harmonics distortion shown in the Fig.9. The value of total harmonics distortion is reduced from
the 23.7% to 2.7%. The harmonic current caused by the nonlinear load is eliminated to great
extent as depicted in Fig.9. From the waveforms of APF it can be observed from Fig.5. The
source current waveform is tends to almost sinusoidal waveform. After harmonics elimination
with APF, source current is in synchronous with source voltage.
Fig.11. Simulated waveform with power variation.
The simulation study of the photo-voltaic based APF is revealed in Fig.5. It can be
observed from the Fig.3, the simulated response of the APF is same as that of the active power
filter. Before APF operation, source phase current is same as that of load current. After APF
switched-on, source current follows source voltage and leads to sinusoidal as it can be seen from
the Fig.3. When PV-modules are connected on the dc bus of the APF, the MPPT algorithm
estimates the active power from PV-panels. The estimated active power altered the dc bus
voltage reference voltage to injected active power from PV panels to the grid. As this can be seen
from Fig.4, the active power caused by PV modules flow from APF to source is in reverse to the
source current. At the same time, variation in currents waveforms is also observed this variation
is due to the variation in solar insolation.
The APF characteristics with power variation are depicted in the Fig.6. The different
waveform from the spectrum is recognized as photo-voltaic panel voltage, photo-voltaic panel
current and active power generated from PV-panel. The photo-voltaic voltage is same as that of
the dc link voltage of capacitor. The dc side voltage is used for regulating the active power
injected into the grid. As the solar irradiation is constant then the active power generated from
the PV-panel is constant. When the solar insolation increases corresponding increase in the
generated active power is witnessed from the Fig.6. The increase in the active power generated
on dc side of the APF inverter then the corresponding increase in the source current is witnessed
from Fig.5. The peak value of the source phase current increases progressively with injected
compensating current. As the solar irradiance increases then the corresponding sources current
in opposite direction increases, this results in relieving the loading on the source.
Fig.12. Source current THD without APF
Fig.13. Source current with APF compensation.
3.4. CONCLUSION
In this project, photovoltaic inverter based on ANPC is used as a APF. The photo-voltaic APF
is used to eliminate harmonics and carryout active power injection from the photovoltaic system
to the grid. The PV-APF does not require the separate inverter power circuit to for harmonics
eliminations and reactive power compensation to meet the load demand. The reference current
estimation PV-APF is carried out with IRPT method. The maximum power point tracking
algorithm is implemented based on incremental conductance method. The MPPT algorithm is
integrated with IRPT method to track the active power and compensates harmonics currents of
the load. The active power computed from the PV-modules is used to regulate the dc side voltage
of the APF. The reference dc link voltage changes corresponding change in active power injected
to the grid are observed. The ANPC based APF shows the promising results for simultaneous
compensation of harmonics and active power injection without requirement of separate ANPCAPF.
Chapter 4
4.1. Conclusion
This these dealt with diode bridge rectifier based battery charger integrated with photo-voltaic
active power filter. The active power filter is used to eliminate the harmonics current and inject
the active power to the grid and relieve the power demand from the source.
The IRPT control scheme is used for the control of APF to eliminate the harmonics caused by
load. IRPT algorithm. The IRPT algorithm is used to compute the active and reactive power and
eliminates the load of harmonics and reactive power of the load. From simulation results, it can
be confirmed that the active power filter with IRPT method can eliminates the harmonics caused
by the diode rectifier based battery charger. And also feed active power to the source.
Also, the DCMLI and ANPC is used as active power filter to eliminate harmonics current and
fed active power to the source from PV modules. The Dc link control of the IRPT algorithm has
been combined with the MPPT algorithm to track the maximum power from the photo-voltaic
cell. Increasing conducting mechanism is implemented to obtain maximum power from photovoltaic cells.
4.2. Future scope
The grid interconnection of renewable energy is emerging field of power electronics application.
1. Active power filter performance characteristic can be carried with all non-conventional
energy sources such as biomass, solar thermal and photo-voltaic power generation
2. The single-stage conversion with active power filter performance characteristics can be
carried out with integration the renewable energy source without requirement of the
separate inverter circuit.
3. Sliding mode controller can be implemented with neural network is the potential area of
research
4. Different maximum power point tracking algorithm performance can be investigated with
different control scheme.
Acknowledgement
Thanks Science and research board of Department of Science and Technology providing
fund under ECR scheme File No. ECR/2016/000813.
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