Simulation of Single Phase Active Power Factor Pre Regulator

International Journal of Trend in Scientific Research and Development (IJTSRD)
Volume 6 Issue 7, November-December 2022 Available Online: www.ijtsrd.com e-ISSN: 2456 – 6470
@ IJTSRD | Unique Paper ID – IJTSRD52594 | Volume – 6 | Issue – 7 | November-December 2022 Page 1291
Simulation of Single Phase Active Power Factor Pre-Regulator
Dr. G. Madasamy
Lecturer, Department of Electrical and Electronics Engineering,
P.A.C. Ramasamy Raja Polytechnic College, Rajapalayam, Tamil Nadu, India
ABSTRACT
The objective of active power factor correction is to make the input
to a power supply look like a simple resistor. An active power factor
corrector does this by programming the input current in response to
the input voltage. As long as the ratio between the voltage and
current is a constant the input will be resistive and the power factor
will be unity. When the ratio deviates from a constant, the input will
contain phase displacement, harmonic distortion or both and either
one will degrade the power factor. The most common definition of
power factor is the ratio of real power to apparent power. A boost
regulator is an excellent choice for the power stage of an active
power factor corrector, because the input current is continuous and
this produces the lowest level of conducted noise and the best-input
current waveform. The boost regulator input current must be forced
or programmed to be proportional to the input voltage waveform for
power factor correction. Feedback is necessary to control the input
current and either peak current mode control or average current mode
control may be used. Both techniques may be implemented with the
UC3854.
KEYWORDS: Power Factor Correction (PFC), Active Power Factor
Correction (APFC), Average Current Mode Control (ACMC)
How to cite this paper: Dr. G.
Madasamy "Simulation of Single Phase
Active Power Factor Pre-Regulator"
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of Trend in
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and Development
(ijtsrd), ISSN: 2456-
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INTRODUCTION
Most switching power supplies operates from a 50 or
60 Hertz AC line with a capacitive input filter. This
type of filter draws current from the line only when
the line voltage exceeds the filter capacitor voltage,
and the filter capacitor is charged to near the peak
level of the input line voltage. This means that the
input current only flows for a short period near the
peak of the input voltage waveform, causing the
current to flow as a series of short, narrow pulses
rather that the smooth, sinusoidal current that would
result from a resistive load.
How does PFC work?
The goal of power factor correction is to make input
current look like input voltage on a moment by-
moment basis, the same as it would with a resistive
load. Fig.1 Shows line voltage and line current with
and without power factor correction.
Power Factor Correction Techniques:
In recent years, single-phase switch-mode ac-to-dc
power converters have been increasingly used in the
industrial, commercial, residential, aerospace, and
military environment due to the advantage of high
efficiency and smaller size and weight. However, the
proliferation of the power converters draw pulsating
input currents from the utility line, this not only
results in poor power factor of the converters but also
injects a significant amount of harmonic current into
the utility.
Fig.1 Effect of PFC on Line Current
The power factor correction methods are classified as:
(a) Passive power factor correction techniques and
(b) Active power factor correction techniques
Passive Power Factor Correction Technique:
In this method an L-C filter is inserted between the
AC mains line and the input port of the diode rectifier
of ac-to-dc converter. This technique is simple and
rugged but has bulky size and heavy weight and
power factor cannot be very high.
IJTSRD52594

International Journal of Trend in Scientific Research and Development @ www.ijtsrd.com eISSN: 2456-6470
Active Power Factor Correction Technique:
In this method, power electronics techniques are used
to shape the input current drawn by the ac-to-dc
converter in to a sinusoidal waveform and in phase
with the input voltage. Thus, the power factor can
reach almost unity and the ac to dc interface of the
power converter emulates a pure resistor.
Active Power Factor Correction:
A boost regulator is the most popular choice for the
power stage of an active power factor corrector,
because the input current is continuous and this
produces the lowest level of conducted noise and the
best-input waveform. The output voltage must be
greater than the highest expected peak input voltage.
Boost regulator input current must be forced or
programmed to be proportional to the input voltage
waveform for power factor correction. Feedback is
necessary to control the input current and either (i)
peak current control or (ii) average current mode
control may be used. Both techniques may be
implemented with the UC3854
Principle of Average Current Mode Control:
Average current mode control is based on a simple
concept. An amplifier is used in the feedback loop
around the boost power stage so that input current
tracks the programming signal with very little error.
This is the advantage of average current mode control
and it is what makes active power factor correction
possible. Average current mode control is relatively
easy to implement.
Basic Scheme of PFP with Average Current Mode
Control:
Fig.2 shows a boost PFP with average current control.
The large bandwidth current error amplifier Gi(s)
forces the input current, sensed by resistor Rs, to
follow as close as possible a suitable sinusoidal
reference signal. This latter is generated by
multiplying a scaled version of rectified voltage Vg
by the output of the voltage error amplifier. Thus, the
voltage loop adjusts the current reference amplitude
to keep the output voltage constant and equal to VREF.
The third input of multiplier M1 is fed by a signal
proportional to the line voltage RMS value obtained
from vg by using a low-pass filter.
This feed forward action helps the system response to
line variations: in fact, with constant output power, an
increase of the input voltage must correspond to a
proportional decrease of the input current, which is
provided by the feed forward path without need of
voltage loop intervention.
In the assumption of unity power factor and
negligible input inductor energy, the fluctuating input
power causes a low-frequency voltage ripple ∆vo
across Co which depends only on the load current and
is given by:
Where is the line angular frequency (rad/s) and Po
the output power. This holds provided that the voltage
loop has a bandwidth well below the line frequency,
in order to avoid variation of IREF (t) within the line
cycle, which would cause input current distortion. To
this purpose, a standard controller has a voltage loop
bandwidth in the range 10-20Hz. This fact, gives a
poor dynamic response to load variations.
Fig.2 Basic Scheme of the Boost PFP with Average Current Mode Control

Simulation Diagram of Single Phase Active Power Factor Pre-Regulator:
SIMULINK is software package for modeling, simulating and analyzing dynamical system. It supports linear
and nonlinear system, modeled in continuous time, sampled time, or a hybrid of the two; system can also be
multirate, i.e., have different parts that are sampled or updated at different rates.
Fig.3 shows the SIMULINK Block Diagram. Fig.4 shows the simulation output waveform. The comparison
results are shown in Table I and the comparison graph is shown in Fig.5.
Fig.3 Simulation Diagram for Single Phase Power Factor Pre-Regulator
Simulation Output Waveform:
Fig. 4 Input Line Voltage and Current Waveform at VIN=220V

Simulation Test Results:
Table I Simulation Results of Various Parameters at VIN=220V (With PFC)
Load (%) Input line current (A) Power factor (p.u) THD (%) Output DC voltage (V)
20 9.20 0.9860 13.37 394
40 9.68 0.9893 12.15 394
60 10.75 0.9915 10.17 394
80 12.25 0.9930 9.75 394
100 13.5 0.9861 15.25 394
Fig.5 Output Power Vs THD for Various Input Voltage with PFC
Conclusion:
Single-phase Active Power factor pre-regulator
simulation using MATLAB SIMULINK for various
input voltages, the input voltage and input current
waveforms are plotted. In converters, the main effort
is devoted to the quality of the input current
waveform but with the simple single switch
topologies like the boost converters, the dynamic
response of the output voltage is sacrificed. This is
due to the input power fluctuation; the output voltage
contains a low frequency ripple at twice the line
frequency that affects the input current waveform
unless the voltage loop bandwidth is kept below the
line frequency (typically 20Hz). Simulation of single
phase Active Power factor Pre regulator for various
input voltage are performed using Simulink. The
simulation results shows that for various input voltage
and input current, power factor is nearly unity. The
harmonics is reduced to 12%. In future, the harmonics
is reduced to 5% such that the quality of input
waveform is increased.
References:
[1] C. Zhou, “Design and Analysis of an Active
Power Factor Correction Circuits, M.S. Thesis,
Virginia Polytechnic Institute and state
University, Sep.1989.
[2] Dixon. U. H, “Average Current Mode Control
of Switching Power Supplies”, Unitrode Power
SupplyDesign Seminar SEM-700, 1990, pp.5-1
to 5-14
[3] N. Mohan, T. M. Undeland and W. P. Robbins,
“Power electronics, converter, application, and
design,” John Wiley & Son, Inc., New York,
1995, 2nd Edition.
[4] P. C. Todd, “UC3854 Controlled Power Factor
Correction Circuit Design”, U-134 Unitrode
Application Note.
[5] V. Ramanarayanan, “Intensive Course
Switched Mode Power Supplies, Analysis,
Modelling and Design”, Center for Continuing
Education, Indian Institute of Science,
Bangalore, India, 1990.
[6] J. B. Williams, “Design of Feedback Loop in
Unity Power Factor Converter,” IEEE
Transaction on Power Electronics, Vol-6, no: 2,
April 1991, pp.179 187.
[7] The Math Works, Inc., “MATLAB Version 6.1
User Guide.
[8] www.powerdesigners.com - Details about
power supply design.
[9] www.ridleyengineering.com - Details about
control loop design.
[10] www.ti.com - Details about IC UC3854.

Simulation of Single Phase Active Power Factor Pre Regulator

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