IRJET- Hybrid Feed Forward Control for Power Factor Correction Rectifier

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 05 Issue: 03 | Mar-2018 www.irjet.net p-ISSN: 2395-0072
© 2018, IRJET | Impact Factor value: 6.171 | ISO 9001:2008 Certified Journal | Page 2083
HYBRID FEED FORWARD CONTROL FOR POWER FACTOR CORRECTION
RECTIFIER
kavipriya.R1, Chitravalavan2
1P.G Student, Dept. of ECE, A.V.C College of Engineering, Mayiladuthurai, TamilNadu
2Professor, Dept. of ECE, A.V.C College of Engineering, Mayiladuthurai, TamilNadu
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Abstract - Simple control architecture is realized using
hybrid feed forward control for a Power Factor Correction
(PFC) rectifier based on a four-switch buck-boost converter.
The converter operates in repeated Conduction Mode, with
gentle changes between the buck and the boost operations
across a line-cycle. To implement the Power FactorCorrection
(PFC) functionality, the controller computes the buck and the
boost duty cycles based on the sensed inductor current and
output voltage. The power converter is simulated in Matlab
Simulink.. The various parameters such as efficiency and
voltage regulations are recorded. This isachievedbydesigning
a controller that controls the load as well as the Single-switch
resonant dc/dc converter. To this end, a FUZZY controller is
designed, which is integrated by a control associated with the
dc load and a control related with the Single-switch resonant
dc/dc converter. The controller works based on the reference
voltage and the output voltage of the converter circuit. The
control allows the constant dc load angular velocity to track a
desired trajectory and also providesthedesiredvoltageprofile
that must be followed by the output voltage of the single-
switch resonant dc/dc converter. The FUZZY controller is
tested through experiments using MATLAB -Simulink. The
obtained results show that the desired voltage trajectory is
well tracked under abrupt variations in the system guideline
and that the controller is robust in such operation conditions,
confirming the validity of the proposed controller.
Key Words: buck-boost converter, digital control ,hysteresis
control, continuous conduction mode, FPGA
1. INTRODUCTION
Operation is based on a voltage or current divider, are
inefficient. They are limited to input voltages greater than
the output voltage. Also, their power density is less because
it needs low-frequency (50 or 60 Hz) line transformers and
filters. Continious regulators, provide a very high aspect
output voltage. Their main area of application is at low
power levels as low drop-out voltage (LDO) regulators.
Electronic devices in continuous regulators conduct in their
active modes. The dc to dc converters can be split into two
main types: hard-switching pulse width modulated (PWM)
converters, and resonant and soft-switching converters.
Advantages of PWM converters include low component
count, high efficiency, constant frequency operation,
relatively simple mastery and economic availability of
integrated circuit controllers, and power to achieve high
alteration ratios for both step-down and step-up
applications.
Pulse-Width Modulation (PWM) or Pulse-Duration
Modulation (PDM) is a modulation method used to encrypt
a message into a pulsing signal. Although this modulation
technique can be used to encode information for
transmission, its main use was to allow the control of the
power supplied to electrical devices, especially to inertial
loads such as motors. In addition, PWM is an one of the two
principal algorithms used in photovoltaic solar battery
chargers, the other being maximum power point tracking.
The average value of voltage and current fed to the load was
controlled by turning the switch betweensupplyandloadon
and off at a fast rate. The longer the switch is oncomparedto
off periods, the higher and total power supplied to the load.
The main advantage of PWM was that power loss in the
switching devices was very low. When a switch is off there
was practically no current, and when it on and power is
being transferred to the load, there is almostnovoltagedrop
across the switch. Power loss, being the product of voltage
and current, is thus in both cases close to zero. PWM also
works well with digital controls, which, because of their
on/off nature, can easily set the needed duty cycle PWM has
also been used in certain communication systems where its
duty cycle has been used to convey information over a
communications channel.
2. BACKGROUND RESERCH AND REVIEW
Most of the present technology and electronic equipment
basically necessitate the function of a switching converter,
particularly DC/DC and AC/DC converters. Switching
converters find application where a fixed and regulated
voltage source is of prime importance to deliverappropriate
power consumption to the systems. Such systems include
communications, computers,mobiletechnology,automobile
industry, and some high-frequency switching converter
applications. The main objective of switching converter is
voltage regulation the ability to keep the output voltage
stable in the event of input voltage and/or load current
variations. Feedback control technique is used to achieve
this goal. The voltage regulation of most DC/DC and AC/DC
converters is dominantlyaccomplishedusinganalogcircuits.
One of the reasons is that analog components can benefit
more from simplicity, high bandwidth, and low cost.
However, unfortunately, most analog circuits are very likely
susceptible to environmental noise. In addition, the fast
proliferation of digital integrated circuits, which requires
lower supply voltage, programmability, lesssusceptibility to
environmental variations, and fewer part counts, so the

performance and flexibility can be enhanced, has given the
analog control a significant challenge incapable of achieving
these requirements. Utilizing digital controller IC provides
numerous advantagesthananalogIC.Theresearchofdigital-
controlled power converter design now plays a very
important role in the power electronics field.
The digital control techniques for power quality
improvement have been discussed and also the modeling of
a digitally controlled switching power supply system is
presented. Simulation and experimental results add to the
merits of the paper. Also FPGA module for PWMgenerator is
presented with its advantages. From the research point of
view all the main contributions to digital solutionsforpower
supplies demonstrate control approaches with minimum
hardware resources and reduced complexity. Feasibility of
completely integrated digital controllers is demonstrated.
The authors of the paper deals thatthetechniquespresented
beneficial to designers, users, manufacturers and research
engineers dealing with power quality improvement
research.
The excessive use of computers and
telecommunication equipment has resulted in high demand
for the switch mode power supplies. The fast growing
market of clean and pollution free renewable energy
domains like fuel cell, solar photovoltaic and wind energy
rely on effective and efficient conversion of electrical power.
Hence, the use of power electronic converters has become
very common. In general, DC-DC converters are non-linear
and time varying in nature and are subjected to varying line
voltages and wide range of uncertain load changes. Due to
these conditions, converter's performance deteriorates
significantly. In spite of a lot of research on high
performancecontrol techniquesforDC-DCpowerconverters
there exists a need for effective and flexible controllers
which can perform tight regulation underunpredictableline
and load disturbances. A boost type DC-DC converter in
particular has an RHP zero that depends on the load, which
is highly uncertain. Hence, from the control design
perspective, this makes the control of boost converter a
challenging task for the researchers and imposes limitation
on the achievable performance. The transfer function
approach, employed to mathematically model DC-DC power
converters, is used to design most of the linear controllers.
Methods available for modeling these DC-DC switching
power converters are: (i) State space averaging method; (ii)
Circuit averaging (iii) Averaged switch modeling .
3. Four-Switch Resonant Dc–Dc Converters
Simple control architecture to allow the four switch buck-
boost converter to achieve PFC functionality. The converter
is operated in Continuous Conduction Mode (CCM) across
the line cycle and controlled using hybrid feed forward
control. It is shown that to implement PFC operation, only
two sensors (an inductor current sensor and an output
voltage sensor) are required, as opposed to the requirement
of three sensors in the traditional boost ac-dc converter,
simplifyinghardwarerequirements.Additionally,thecontrol
architecture is relatively simple to implement, achieves
automatic mode transition between the buck and boost
modes with negligible or no input current distortion at the
mode transitions, and can achieve good performance in
terms of power factor and efficiency. The Ideal operation of
the four-switch buck-boost converter acting as a PFC
rectifier. The design criteria for selecting the converter
component values. The converter comprises a buck stage
and a boost that share the same inductor.
Fig.1 Block diagram
When the converter is used for PFC operation, the output
voltage of the converter can beanyvoltagegreaterthanzero,
including lower than the peak input voltage. Thus, the
converter operates in the buck mode when the inputvoltage
is greater than the output voltage of the converter and the
boost mode when the input voltage is less than the output
voltage For ideal operation of this converter, the mode
transition should happen instantaneously when the input
line voltage is equal to the output voltage of the converter.
Two importantconsiderationsassociatedwiththisconverter
topology selection and energy buffering capacitor selection
are discussed below The four switch buck-boost converter
can be realized as a synchronous or as an asynchronous
converter, the converter remains in the Continuous
Conduction Mode (CCM) over the entire line cycle. On the
other hand, in the asynchronous version, the converter can
operate in both CCM and discontinuous conduction mode
(DCM).
3.1 RESISTIVE DC LOAD
The load resistance or, more generally,theloadimpedanceis
the equivalent resistance of the device attached to the
output of a given circuit or system. For instance, the
equivalent impedance of a loud speaker is the "load
impedance" of an audio amplifier. Common room loud
speakers' impedance, but this varies with frequency, and

often some resistors and capacitors are attached in parallel
with the loudspeakers to "build" the rated impedance of
8 [math]Omega[/math]. An example of a typical
loudspeakers' impedance curveisbelow:itvariessomewhat
"wildly" with the frequency. So, this is the load impedance
seen by an audio amplifier. As another example, the
equivalent resistance of a toaster is a "load resistance"
attached to your home power grid when you are having tea
and roasting toasts. In general, the loadresistancecanbe the
input impedance of some othercircuitmountedincascadeat
the output of the circuit "which is being loaded". This
happens in multistage amplifiers. The picture below depicts
this general case:the destination block istheloadimpedance
of the source block which models a generator.
4. PRINCIPAL OF WORKING
Fig.2: Implementation Diagram
4.1 EQUIVALENT CIRCUIT
Fig 3: Equivalent Circuit of Resistive DC Load
As in RESISTIVE load the field is produced byresistive;there
is no need of drawing field coils in the equivalent circuit of
resistive dc load. The supply voltage to the armature will
have armature resistance drop and rest of the
supply voltage is countered by back emf of the load.
Hence voltage equation of the load is given by,
Where I, is armature current and R is armature resistance of
the load. Eb is the back emf and V is the supply voltage.
4.2 FUNDAMENTAL OF FRACTIONAL CALCULUS
Fractional calculus is an old mathematical topic since 17th
century. Fractional calculus is a subdivision of calculus
theory which generalizes the derivative or integral of a
function to non -integer order. Fractional calculus helps
evaluating (dny/dtn) n-fold integrals where n is fractional,
irrational or complex. For FUZZY systems n is considered to
be fractional. The number of applications where fractional
calculus has been used rafuzzyly grows.Thesemathematical
phenomena allow describing a real object more accurately
than the classical “integer-order” methods. The real objects
are generally fractional however, for many of them the
fractionality is very low. The main reason for using the
integer -order models was the absence of solution methods
for fractional differential equations. At presenttherearelots
of methods for approximation of fractional derivative and
integral and fractional calculus can be easily used in wide
areas of applications (e.g.: control theory - new fractional
controllers and system models, electrical circuits theory -
factices, capacitor theory, etc.).
The theory of fractional-order derivative was developed
mainly in the 19th century. There are several definitions of
fractional derivative. Two important and widely applied
definitions are: Grunwald-Letnikov definition is perhaps
the best known one due to its most suitable for the
realization of discrete control algorithms.
The Grunwald-Letnikov definition is:
  )jht(f
j
1hlim)t(faD
j
h
at
0j0ht 




 
  




 




Where [x] means the integer part of x and h is time step.
The Riemann-Liouville definition is given as:






d
)t(
)(f
dt
d
)an(
1
)t(f t
a 1nn
n
For a wide class of functions which appear in real physical
and engineering applications, the Riemann-Liouvilleandthe
Grunwald - Letnikov definitions are equivalent.
4.3 FUZZY CONTROL SYSTEM
A FUZZY controller is represented asFIS. It allows us to
adjust derivative (λ) and integral (µ) order in addition to
the proportional, integral and derivative constants where
the values of λ and µ lie between 0 and 1. This also
provides more flexibility and opportunity to better adjust
the dynamical properties of the control system. The
FUZZY controller gives good robustness. The robustness of
fractional controller gets more highlighted in presence of a
non-linear actuator. Fig. 2.2 showstheconceptofa fractionalFUZZY control system.

Fig 4: FUZZY control system
Applying Laplace transform to this equation with null initial
conditions, the transfer functions of the controller.
Taking =1 and µ=1, we can obtain a classical FUZZY
controller. If λ=0 we obtain a PDµ controller, etc. All these
types of controllers are the particular cases of the PIλDµ
controller. Actually, in theory, itself is an infinite
dimensional linear filter due to the fractional order in
differentiator or integrator.
It can be expected that controller may enhance the
system control performance due to more tuning knobs
introduced. Actually, in theory it is an infinite dimensional
linear filter due to the FUZZY.
5. SIMULATION RESULTS OF RESISTIVE CONTROL
USING FUZZY CONTROLLER
5.1 MATLAB
MATLAB is one of the most successful software packages
currently available. It is a powerful, comprehensiveanduser
friendly software package for simulation studies.Avery nice
feature of Simulink is that it visually represents the
simulation process by using simulation block diagram.
Especially, functions are then interconnected to form a
Simulink block diagram that defines the system structure.
Once the system structureisdefined,parametersare entered
in the individual subsystem blocks that correspond to the
given system data. Some additional simulation parameter
must also be set to govern how the computation is carried
out and the output data will be displayed.
5.2 DEVELOPMENT ENVIRONMENT
It incorporates a set of tools and facilities that allows theuse
of MATLAB function and files. Most of these tools are of
graphical user interface in nature. It includes the MATLAB
desktop, a command window, a command history, editor,
debugger and browsers for viewing help, the workspace,
files and the search path.
6. CONCLUSION
Motivated by the FUZZY controller approach applied in the
mobile robotics area, a solution for the voltage trajectory
tracking problem for the Single-switch resonant dc/dc
converter DC load system was presented. According to the
simulation results, the voltage of the load tracks a desired
voltage trajectory. The obtained results have shown the
robustness of the FUZZYcontroller whenuncertaintiesoccur
in the system’s power supply E, the converter load R, the
inductance L, and the capacitance C, as well as in the
coefficient b, control signal ϑ, and load voltage. It is
important to underline that these types of abrupt variations
do not happen in practice at the same time, or with such
large variations regarding their nominal values. However,
this system were undertaken to demonstrate that the
proposed controller presents a good performance under
abrupt variations associated with the system parameters,
which would make possible the introduction of this
controller in practical applications.
7. REFERENCES
[1] Limits for Harmonic Current Emissions (Equipment
input current”16 A per phase), International Standard
IEC 61000-3-2, 2010.
[2] B. Singh, B. N. Singh, A. Chandra, K. Al-Haddad, A.
Pandey and D.P. Kothari, “A review of single-phase
improved power quality AC-DC converters,” IEEE
Transactions on Industrial Electronics, vol. 50, no. 5,
pp. 962– 981, Oct. 2003
[3] S. E. Lyshevski, Electromechanical Systems, Electric
Machines, and Applied Mechatronics. Boca Raton, FL,
USA: CRC Press, 2009.
[4] J. Linares-Flores and H. Sira-Ram´ırez, “A low switch
voltage stress for a DC machine: A flatness based
approach,” in Proc. 1st Int. Conf. Electr. Electron. Eng.,
Acapulco, Mexico, Sep. 8–10, 2014, pp. 589–594.
[5] J Sokira and W. Jaffe, Brushless DC Loads: Electronic
Commutation and Control, Tab Books, USA, 2009.
[6] J. R. Handershot and T.J.E Miller, Design of Brushless
Resistive Loads, Clarendon Press, Oxford, 2014.
[7] J. F. Gieras and M. Wing, Resistive Load Technology –
Design and Application, Marcel Dekker Inc., New York,
2012.
[8] N. Mohan, T. M. Undeland and W. P. Robbins, Power
Electronics: Converters, Applications and Design, John
Wiley and Sons Inc, USA, 2009.
[9] S. Singh and B. Singh, "Voltage controlled PFC Zeta
converter based BLDC LOAD drive for an air-
conditioner," 2010 International Conference on
Industrial andInformationSystems(ICIIS),pp.550-555,
29th July 2010- 1st Aug. 2010.
[10] H. El Fadil and F. Giri, “Accounting of DC-DC power
converter dynamics in DC load velocity adaptive
control,” in Proc. IEEE Int. Conf. Control Appl., Munich,
Germany, Oct. 4–6, 2011, pp. 3157–3162.
FUZZY G
K, T, λ, T, µ
W E U Y

IRJET- Hybrid Feed Forward Control for Power Factor Correction Rectifier

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IRJET- Hybrid Feed Forward Control for Power Factor Correction Rectifier