ISSN 2394-3777 (Print)
ISSN 2394-3785 (Online)
Available online at www.ijartet.com
International Journal of Advanced Research Trends in Engineering and Technology (IJARTET)
Vol. II, Special Issue XIII, March 2015
Modified Bridgeless Resonant Converter with
Power Factor Correction for LED Applications
V. Velmurugan1, Dr.A. Gnanasaravanan2, R. Arul Jose3
PG Scholar, Power Electronics and Drives, SCAD College of Engineering and Technology, Tirunelveli, India 1
Professor, SCAD College of Engineering and Technology, Tirunelveli, India 2
Assistant professor, SCAD College of Engineering and Technology, Tirunelveli, India 3
Abstract: In the past decade, there is growing awareness about line pollution and deteriorating power factor due to all
pervading inductive and non-linear loads. In many real time applications, the conventional diode rectifiers are used to
provide a DC supply. The diode rectifiers are non linear in nature and consequently generate harmonic currents in AC line
power resulting in low power factor and high percentage total harmonic distortion (THD). The harmonic distortion has
several detrimental effects including poor power factor, low percentage efficiency and interfere with the communication,
control circuits nearby. This project proposes a novel single-stage Light-Emitting Diode (LED) driver for street-lighting
applications with power-factor-corrections. The presented driver integrates a modified bridgeless power-factor-correction
(PFC) AC-DC converter with a half-bridge-type LLC DC-DC resonant converter into a single-stage conversion circuit
topology. The proposed AC-DC resonant driver provides input current shaping, and it offers attributes of lowered switching
losses to the soft-switching functions obtained on two power switches and two output-rectifier diodes. The proposed driver
features cost-effectiveness, high circuit efficiency, high power factor and low input current total-harmonics-distortion THD.
I. INTRODUCTION
Light emitting diodes (LEDs) have favourable features of
smaller size, longer lifetime, lower maintenance costs,
greater strength against breakage, and being mercury free
and therefore less harmful to our environment than
traditional lighting sources. Thus, LEDs have become
increasingly common in our daily lives. They are well suited
to indoor and outdoor energy saving lighting applications,
such as traffic lighting, background lighting, displays, street
lighting, automotive automotive and motorcycle lighting,
decorative lighting, and so on.
The installation of street lights is closely related to
the development of one area or region, and they represent
the financial success of a city. For street lighting
applications, the traditional lighting sources are high
intensity discharge (HID)
high striking voltage for starting the lamp up and an extra
high ignition voltage in the hot restart status, and that they
offer a long lifetime in comparison to their traditional
counterparts. Table I shows some comparisons between
traditional and new lighting sources for street-lighting
applications. The traditional lighting source is a high
pressure sodium lamp (such as a 150W OSRAM NAV-E
lamp), and the new one is an LED lamp (a 144W AcBel
LM9003-003 G/GT lamp for example) as an alternative
option for street lighting circumstances. The LED lamp
consumes less power and has better color rendering index
and longer lamp life than the traditional one. Instead of
traditional HID lighting sources such as high pressure
sodium lamps and high pressure mercury lamps, LED,
which offers features of satisfying lighting efficiency,
reduced power consumption, and long lifetime, will play an
important role for streetlight applications in the future.
II. A BRIDGELESS POWER FACTOR CORRECTION
Lamps, such as high-pressure sodium lamps and
CONVERTER USING LLC RESONANCE CONVERTER
high- pressure mercury lamps. Recently, LEDs are
commonly being used as new sources for street lighting
The proposed driver for powering an LED street-lighting
applications due to their attractive characteristics of good
module
with a rated LED power of larger than 70 W is
color rendering index (CRI), energy savings, being mercury
presented.
It combines a modified bridgeless PFC AC-DC
free, quickly turning on and off, that they do not require a
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ISSN 2394-3777 (Print)
ISSN 2394-3785 (Online)
Available online at www.ijartet.com
International Journal of Advanced Research Trends in Engineering and Technology (IJARTET)
Vol. II, Special Issue XIII, March 2015
converter with a half-bridge-type LLC DC-DC resonant
converter into a single stage of power conversion.
Fig.2. The simplified single-stage operational modes.

Mode 1:
The input utility-line voltage VAC is defined
as
When vds1 decreases to zero at time instant t0, this
mode begins. The power switch S1 turns on with zerovoltage switching (ZVS). The utility-line voltage VAC
charges the inductor Lb through the diode D1. The inductor
The single-stage driver consists of a filter inductor Lf, a current i linearly increases, and it is given by:
Lb
filter capacitor Cf, an inductor Lb, two diodes D1 and D2,
two power switches S1 and S2, a DC-linked capacitor CB, a
resonant capacitor Cr, an inductor Lr, a centre-tapped
transformer T1 with two output windings, two diodes D3 and
D4 and a capacitor Co, along with the LED street-lighting
module. Fig. 4.2 also shows the block diagram for
controlling the single-stage LED driver, and the presented
control circuit is shown in, a constant-voltage and constantcurrent (CV-CC) controller (IC1 SEA05) is adopted to sense
the output voltage through resistors Rvs1 and Rvs2, while
simultaneously sensing the output current through the
Fig.3. Mode 1
resistor Rcs for supplying the rated voltage and current to
The inductors Lm and Lr provide energy to Cr and
the experimental LED street-lighting module. The output
C through the body diode of S1, and to capacitor Co along
signal of the CV-CC controller feeds into the high-voltage B
with the LED street-lighting module through diode D3. At
resonant controller (IC3 L6599) through a photo-coupler
time instant t1, the inductor current iLr becomes zero. In
(IC2 PC817). Two gate-driving signals vgs1 and vgs2
addition, the DC-linked capacitor CB provides energy to Cr
generating from the resonant controller regulate the output
and Lr through the switch S1, and the magnetic inductor Lm
voltage and current of the LED street-lighting module by
provides energy to the capacitor Co along with the LED
utilizing variable-frequency control scheme. Moreover, the
street-lighting module through diode D3. At time instant t2,
inductor Lb is designed to be operated at discontinuousthe inductor current iLm increases to zero. Moreover, the DCconduction mode (DCM) for naturally achieving power
linked capacitor CB provides energy to Cr, Lr and Lm through
factor corrections.
the switch S1, and to the capacitor Co along with the LED
street-lighting module through diode D3. When iD3 decreases
III. MODES OF OPERATION
to zero, Mode 1 ends.
Fig. 5.1 presents the simplified single-stage LED
 Mode 2:
driver for supplying the street-lighting module used to
At t3, the utility-line voltage vAC still charges the
analyze the operational modes for the positive utility-line
inductor Lb through the diode D1. Current iLb reaches its
half cycle (the analysis for the negative one is similar).
maximum values iLb-pk(t), and can be respectively expressed
as
Fig.1. LLC DC-DC Converter
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International Journal of Advanced Research Trends in Engineering and Technology (IJARTET)
Vol. II, Special Issue XIII, March 2015
Where TS and D are the switching period and duty
cycle of two power switches, respectively.
Fig.4. Mode 2
The DC-linked capacitor CB provides energy to Cr, Lr
and Lm through the switch S1. The capacitor Co supplies
energy to the LED street-lighting module. When iLM is equal
to iLr, Mode 2 ends.
 Mode 3
The utility-line voltage vAC and the inductor Lb
provide energy to the capacitor CB through the diode D1, and
iLb starts to linearly decrease at t4. The DC-linked capacitor
CB along with the intrinsic capacitor CS2 provides energy to
Cr, Lr and Lm. The capacitor Co still supplies energy to the
LED street-lighting module. When vds2 decreases to zero at
t5, Mode 3 ends.
The magnetic inductor Lm provides energy to Cr
and Lr through the body diode of S2, and to capacitor Co
along with the LED street-lighting module through diode D4.
When S2 turns on, Mode 4 ends.

Mode 5
While S2 is on at t6, Mode 5 begins. The inductor
Lb still provides energy to the capacitor CB through the diode
D5, and iLb linearly decreases. The inductor Lr provides
energy to Cr through the switch S2, and the magnetic
inductor Lm provides energy to capacitor Co along with the
LED street-lighting module through diode D4. When iLb
decreases to zero, Mode 5 ends
Fig.7. Mode 5

Mode 6
At t7, the inductor current iLb is zero. The
inductor Lr still provides energy to Cr through the switch S2,
and the magnetic inductor Lm still provides energy to
capacitor Co along with the LED street- lighting module
through diode D4. When iLm decreases to zero, Mode 6 ends.
Fig.5. Mode 3
Mode 4
At t5, the inductor Lb provides energy to the
capacitor CB through the diode D5, and iLb linearly decreases
with a down slope of (vAC(t)-VDC)/Lb. The inductor current iLb
is given by

Fig.8. Mode 6

Mode 7
The inductor Lr still provides energy to Cr and
Lm through the switch S2, and to capacitor Co along with the
LED street-lighting module through diode D4 during Mode
7. When iD4 decreases to zero, Mode 7 ends.
Fig.6. Mode 4
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ISSN 2394-3777 (Print)
ISSN 2394-3785 (Online)
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International Journal of Advanced Research Trends in Engineering and Technology (IJARTET)
Vol. II, Special Issue XIII, March 2015
Operational Modes 1 to 9 perform in the positive half-cycle
of input utility-line voltage, while Modes 10 to 18 occurs in
the negative half-cycle.
IV. DESIGN OF CONVERTER
This section presents a design procedure for the proposed
LED street- lighting driver, and a 144W-rated LED streetlighting module with 36V/4A output has been selected as a
design example. The design specifications are listed as
follows.
Fig.9. Mode 7

Mode 8
At t9, the capacitor Cr provides energy to Lr and Lm 1) Input utility-line voltage (rms value): Vac-rms = 100V (Vacthrough the switch S2, and the capacitor Co provides energy MIN) ~120V (Vac-MAX).
to the LED street-lighting module. When S2 turns off at t10, 2) Input utility-line frequency: Fac= 60Hz
Mode 8 ends.
3) Rated power of LED street-lighting module: Po = 144W
4) Rated voltage of LED street-lighting module: Vo = 36V.
5) Rated current of LED street-lighting module: Io = 4A.
Fig.10. Mode 8

Mode 9
The capacitors CS1 and Cr provide energy to Lr,
Lm, CS2, CB and LB2, and the capacitor Co still provides
energy to the LED street-lighting module during Mode 9.
When vds1 decreases to zero at t11, Mode 9 ends and Mode 1
begins again for the next switching period.
Fig.11. Mode 9
V. SIMULATION ANG RESULTS
Fig.12. Simulation circuit of single phase closed loop
resonant converter
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ISSN 2394-3777 (Print)
ISSN 2394-3785 (Online)
Available online at www.ijartet.com
International Journal of Advanced Research Trends in Engineering and Technology (IJARTET)
Vol. II, Special Issue XIII, March 2015
Fig.13. Measured switch voltage (ZVS)
Fig.14. Measured voltage and resonant current
Measured waveform of switching voltage vds2 along with the
switching current ids2 and ZVS is obtained on the power
switch S2. The measured voltage vds2 and resonant current iLr
is shown in above Fig
VI. CONCLUSION
Although many solutions were offered for single-phase
active PFC, three-phase active PFC was seldom considered.
In this project work, the performance analysis of single stage
resonant converter with hysteresis controller has been
simulated achieving voltage regulation and power factor
nearly equal to unity under line and load variations. The
presented LED driver for street-lighting applications have
demonstrated cost- effectiveness, high circuit efficiency,
high power factor, low total harmonic distortion of input
utility-line current, satisfying output voltage ripples and
current ripples at a 230 V input utility-line voltage, zerovoltage switching on power switches, and zero-current
switching on output-rectifier diodes.
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