International Electrical Engineering Journal (IEEJ)
Vol. 7 (2016) No.2, pp. 2161-2166
ISSN 2078-2365
http://www.ieejournal.com/

Single Stage Power Conversion with high
power factor for DC Applications
1
Sruthi Nath S, 2S Sathishkumar
Anna University Chennai
Sruthinath54@gmail.com,ersathis@gmail.com
Abstract—This paper presents a single stage single-phase power
factor correction (PFC) converter that has flexible output
voltage and improved conversion efficiency. The proposed PFC
converter features sinusoidal input current, high range of output
dc voltage, and is suitable for high power applications where the
output voltage can be higher than the peak ac input voltage, e.g.,
electric vehicle charging system. The dynamic response of this
regulation loop is very fast and the system is insensitive to
external disturbances. Simulation results have been presented to
show the effectiveness of this converter, efficiency, as well as its
power factor improvement against a conventional two-stage
solution.
Index Terms—AC/DC converter, power factor correction
(PFC), MATLAB
I. INTRODUCTION
C
ONCEPT of PFC
 If load is linear supply voltage and current
waveforms are sinusoidal
 The switching power supplies have diode
rectifier on the front end. The current
waveforms are no longer sinusoidal for them,
and thus the definition for power factor
change for them. It is given by
Where DPF=
THD=
Basically we have filters to convert pulsating dc to pure dc.
Whenever we use filters, our line current distorts nothing but
current harmonics. Due to the harmonics source current also
distort. By using custom power devices we control and
mitigate our harmonics. But those are very complex. That’s
why people prefer single stage conversion.
Some power electronics topologies, mainly DC-DC
converters, offer the characteristic of making any switching
load appear as resistive load with unity power factor. In other
words, these controllers draw the line current proportional to
line voltage.
Single phase ac/dc converters are one of the most
common forms of power conversion system. It can be found in
many industrial as well as residential applications-variable
speed drives, electric vehicle chargers, and power supply for
consumer electronics. Presently single phase power factor
correction (PFC) converters are a very popular solution to
ensure the compliance of such regulation because of their
simplicity, cost effectiveness and current shaping capability.
However, most of the existing single-phase PFC converters
are of boost type and can provide output voltage higher than
the peak voltage of ac input.
II. PROPOSED SYSTEM
Figure 1 shows the block diagram of single stage high
power factor converter. It consists of single phase ac supply
given to rectifier unit, then to the dc-dc converter for active
power decoupling and then to load. The dc-dc converter for
active decoupling consists of power factor correction and
dc-dc converter unit, which is responsible for single power
conversion. With the difference in voltage PWM pulse is
generated. This PWM pulse is given as gate pulses for the
converter. Triggering to both the MOSFET is fed by a single
PWM pulse generator.
2161
Sruthi and Sathishkumar
Single Stage Power Conversion with high power factor for DC Applications
International Electrical Engineering Journal (IEEJ)
Vol. 7 (2016) No.2, pp. 2161-2166
ISSN 2078-2365
http://www.ieejournal.com/
Fig. 1.Block Diagram
Fig. 2.Circuit Diagram for Single stage power conversion with high power
factor
The proposed topology as shown in figure2 is a
discontinuous mode, with 2 boost converter circuit switched
alternatively by 2 MOSFET by a single PWM. Hence dc-dc
conversion and power factor correction occur at a single
stage.
The DC-link capacitor after the diode bridge is usually
set at the voltage above 10%, greater than the peak input
voltage. It must be noted that if the peak input voltage exceed
the controlled capacitor voltage the power factor correction is
not achieved. The input current from main is not chopped
directly, because the inductor is placed in series with the
source and this help with EMI. Fortunately, the series choke
at the input of the PFC circuit helps to absorb the line
transients. Some applications of the proposed converter
circuit are E-cars charging applications and laptop adaptors.
The main features include reduce power losses, maintenance
of power factor load life and efficiency. It is also expected that
the output harmonics and load running noises are less. The
inherent fluctuating power issue in single phase systems can
also be resolved, and the load voltage will be fairly constant
and insensitive to load changes and external disturbances.
2162
Sruthi and Sathishkumar
Single Stage Power Conversion with high power factor for DC Applications
International Electrical Engineering Journal (IEEJ)
Vol. 7 (2016) No.2, pp. 2161-2166
ISSN 2078-2365
http://www.ieejournal.com/
III. SIMULATION MODELLING
capacitor making the whole circuit resistive in nature.
The single PWM generator provides pulses to two
MOSFETS alternatively and this makes room for power
factor correction. The power factor correction is done as a
whole through the MOSFET switching, inductor and
Fig 3. Single Stage power conversion with high power factor converter
2163
Sruthi and Sathishkumar
Single Stage Power Conversion with high power factor for DC Applications
International Electrical Engineering Journal (IEEJ)
Vol. 7 (2016) No.2, pp. 2161-2166
ISSN 2078-2365
http://www.ieejournal.com/
Fig.3.1 Input Voltage and Current
Fig.3.2 Output DC voltage
2164
Sruthi and Sathishkumar
Single Stage Power Conversion with high power factor for DC Applications
International Electrical Engineering Journal (IEEJ)
Vol. 7 (2016) No.2, pp. 2161-2166
ISSN 2078-2365
http://www.ieejournal.com/
Fig 3.3 Power factor
2165
Sruthi and Sathishkumar
Single Stage Power Conversion with high power factor for DC Applications
International Electrical Engineering Journal (IEEJ)
Vol. 7 (2016) No.2, pp. 2161-2166
ISSN 2078-2365
http://www.ieejournal.com/
IV. CONCLUSION
The proposed PFC converter features sinusoidal input
current and boosted output voltage and hence suitable for high
power applications. The single stage power conversion with
improved conversion efficiency is possible. Through proper
control of the boost converter, it is also possible to mitigate
the double line frequency ripple power that is inherent in
single phase ac to dc system, and the resulting load end
voltage will be fairly constant. The dynamic response of this
regulation loop is also very fast and the system is therefore
insensitive to external disturbances. As we are reducing the
number of switching components power loss is also getting
reduced.
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Sruthi and Sathishkumar
Single Stage Power Conversion with high power factor for DC Applications