International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 3, Issue 2, February 2013)
Development of Unity Power Factor Electronic Ballast
Kiran Bathala1, Dr. Sunil Kumar T K2
1
Asst.Prof. SRIT Anantapur, A.P-515701, India. Email: kiran0219@gmail.com
2
Assoc.Prof. NIT Calicut, Kerala- 673601, India Email: tksunil@nitc.ac.in
aging and it in turn reduces the lamp life, low input power
factor, over current risk due to ballast saturation caused by
ballast saturation caused by rectifying effect of some
discharge lamps at the end of their life, not suitable for DC
applications(emergency and automobile lighting) and
flickering and stroboscopic effects are the disadvantages of
the electromagnetic ballast. As the advancements of power
electronic takes place, then the design, fabrication and size
of the equipment becomes compact are the added
advantages to the product. In this paper an Electronic
Ballast is designed and implemented in simulink/Matlab
software and hardware. Basically the proposed circuit
consists of the ac input, PFC Boost converter and a high
frequency series resonant parallel loaded inverter.
Section II explains the proposed circuit of Electronic
Ballast and its principle of operation, Section III explains
the design and analysis of the various components that are
present in the total circuit, Section IV explains the
simulation diagram of the total circuit, Section V explains
the Simulation analysis, Section VI explains the hardware
implementation and hardware results analysis and Section
VII explains the conclusion for the total work done in this
paper.
Abstract- Electronic Ballast is used for the Compact
fluorescent lamp (CFL). The present work focus on
development of Electronic Ballast having almost unity power
factor (UPF) improved power quality. The electronic ballast
consists of a PFC (power factor corrected) Boost converter,
which operates in discontinuous conduction mode (DCM), and
a high frequency DC-AC inverter. It overcomes the drawback
of [1] operating the boost converter in open loop by operating
the boost converter in closed loop to provide a constant power
to the load within in the specified ratings irrespective of the
changes in the load. It uses less number of inductors and
capacitors which reduces the cost of the total equipment,
especially at high voltage ratings capacitor and inductor cost
becomes more and overcomes the drawback of [2] high cost at
higher voltage ratings.
In the Series Resonant Parallel Loaded Inverter zero
voltage switching is achieved by keeping the switching
frequency more than the resonance frequency, which reduces
the switching losses and improves the efficiency of the
Electronic Ballast. The simulation is carried out in MATLAB
SIMULINK software. The High Frequency Electronic Ballast,
a SRPLI is used to feed constant current to lamp for specified
voltage range applications. The power quality indices are
calculated such as total harmonic distortion (THDi) of ac
mains current, and power factor (PF) for the analysis of Unity
Power Factor Electronic Ballast
KeywordsBallast,
Compact
Fluorescent
Lamp,
Discontinuous Conduction Mode (DCM), Series Resonant
Parallel Loaded Inverter, Zero Voltage Switching, Unity
Power Factor (UPF).
II. THE PROPOSED CIRCUIT OF ELECTRONIC BALLAST
I. INTRODUCTION
Light is defined as visually evaluated radiant energy,
which stimulates man‟s eyes and enables him to see. Man
has always sought to counter the influence of the darkness
by creating artificial light. The discovery of electric power
and the possibility of transmitting it in a simple manner
facilitated the development of modern lamps. Compact
fluorescent lamps offer higher efficacy, longer life and
have negative impedance characteristics, for that we need
to supply a constant current in order to avoid the damage of
the lamp. Generally we use electromagnetic type of
ballasts, which are rugged in construction and have many
disadvantages like low efficiency, low reliability for
ignition and re-ignition, difficulty in controlling the
dimming of the lamp, lamp operating point changes due to
In the proposed topology, the power conversion takes
place at two levels by using power electronic converters,
whenever power electronic devices come into the picture
then harmonic contents in the circuit will increase and
source current waveform gets distorted. The Power factor
Corrected Boost converter is used to boost up the voltage,
which is essential to ignite the electrodes during the starting
time of the lamp.
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International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 3, Issue 2, February 2013)
Once the lamp gets ignited then we need to supply
stable arc current in order to avoid the damage of the
electrodes even when the voltage reduces to a normal
If the switching frequency is kept more than the steadyvalue. Simultaneously. It will maintain nearly unity power
state resonance frequency then the zero voltage switching
factor when PFC boost converter is operated in
(ZVS) is achieved[2]. Considering that
discontinuous conduction mode. In this discontinuous
conduction mode of operation the input sinusoidal current
waveform will follow the source sinusoidal voltage
The relationship between the lamp voltage and the
waveform automatically, to maintain nearly unity power
fundamental
component of the square voltage source is
factor.
given in the frequency domain as,
III. DESIGN AND ANALYSIS
Generally fluorescent lamp at starting time operates as
open circuit and during the steady state they operate as a
resistor. Under the steady state operating condition the
equivalent circuit diagram[2] of the series resonant parallel
loaded inverter can be shown in fig.1
After solving equations [2] the blocking capacitor is
given as,
On solving equations, [2] the parallel resonant capacitor
is as,
On solving above equations, the resonant inductor is
given as,
IV. MATLAB MODEL
Fig.1 Equivalent Circuit of Series Resonant Parallel
Loaded Inverter.
From the above circuit diagram the resonant circuit
parameters are given as
, Cs and Cp which is in parallel
with the resistor
and finally the
is the
resistance of the fluorescent lamp. The capacitor Cs in the
equivalent circuit is to block the DC component Otherwise
they can distort lamp current. At the time of starting, the
self oscillating technique provides a resonance frequency
(
) which is equal to the switching frequency
(
. The relationship between the resonant circuit
parameters and the starting resonance frequency.
Fig. Closed loop simulation model of Electronic
Ballast
In the steady-state operation the resonance frequency is as
,
415
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 3, Issue 2, February 2013)
II. SIMULATION AND SIMULATION RESULTS
Fig. Input Current and voltage at Source Voltage
110V
Fig. Total Harmonic Distortion of Input Current
V. HARDWARE IMPLEMENTATION
The below block diagram shows the overall circuit of the
Electronic ballast. Hardware is implemented at ac input
voltage of Vm= 30 volts. For the PFC boost converter has
operated in closed loop by using a UC3854 IC. Generally It
is used for power factor correction. The output power of
Fig. DBR Output Voltage at Source Voltage 110V
Fig. Block Diagram of the UPF Electronic Ballast
Fig. Output Voltage waveform of the Boost Converter
Fig. Boost converter with UC3854 PFC Controller
Fig. High Frequency SRPLI output voltage and
Current waveforms.
416
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 3, Issue 2, February 2013)
Fig. Total circuit for the hardware implementation
Fig. pulses to the switches M1 and M2 in SRPL Inverter
from TL494
Fig. Source voltage and current at 30V
Fig. Figure 5.12: output voltage and current at 30V
input voltage
Fig. Output voltage of DBR at 30V
Fig. Output voltage of the boost converter at 30V input
voltage
Fig. Hardware setup for UPF Electronic Ballast
417
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 3, Issue 2, February 2013)
APPENDIX
VI. CONCLUSION
The designed values of Boost converter and Resonant
Inverter are given for an input voltage of 110V rms.
Design of Boost Converter Paramaeters :
Output Power :20W
Boost Inductor Lboost -5.676mH
Capacitor Filter Cdc1 - 30nF
Capacitor Cdc -22microF
Design of Resonant Inverter Parameters :
Capacitor C -68nF
Inductor Lr -2.615mH
Rlamp-605ohms
Capacitor Cp -4.7nanoF
Design of Feedbak Controller :
Frequency of the repetitive Sequence 50kH
Proportional Controller(kp) – 0.0028
Integral Controller (Ki) – 0.038
In Hardware Implementation the lamp is wattage is 5watts.
A UPF boost converter based HF electronic ballast is
developed with improved power quality for ac main
voltage. The electronic ballast with PFC boost converter
has shown high performance such as nearly Unity Power
Factor. The dc link voltage has been maintained constant,
which realizes the constant lamp power irrespective of the
changes in the load, with an appropriate design of PFC
boost converter and resonant inverter parameters, the lamp
current has been maintained sinusoidal and close to the
rated value. The developed electronic ballast has THD of
ac mains current under 14.34%. The zero voltage switching
(ZVS) has confirmed because switching frequency has
maintained more than the resonance frequency of the
resonant inverter, which reduces the switching losses and
improves the efficiency of electronic ballast.
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