International Journal of Innovations in Engineering and Technology (IJIET)
http://dx.doi.org/10.21172/ijiet.114.09
A Novel DC-DC Boost Converter Based on
Voltage-Lift Technique
Nihala K Shereef1, Neena Mani 2, Neetha John 3
1
Post Graduate Student, Department of EEE, Mar Athanasius College of Engineering,
2,3
Kothamangalam , Kerala India
Assistant Professor, Department of EEE, Mar Athanasius College of Engineering,
Kothamangalam , Kerala India
Abstract—Nowadays, DC-DC converters are widely used. These types of power electronic converters are controlled
using pulse width modulation (PWM) and switching frequency. Different topologies of converters are introduced to
improve the efficiency. Here a new structure of non-isolated boost DC-DC converters based on voltage-lift (VL) technique
is explained. This converter is designed with less number of components. In comparison with conventional non-isolated
boost DC-DC converters, the defined converter generates higher voltage gain. The voltage and current waveforms of all
elements in continuous conduction mode (CCM) are observed. Then, the critical inductance and stress of switch current
are extracted. Switching pulse is generated using PIC16F877A. The validity of all the theories is examined experimentally.
The prototype of the hardware is implemented and output voltage of 35V is observed with an input voltage of 5V.
Keywords— DC-DC Converter, Continuous Conduction, Critical inductance, Voltage Lift
I. INTRODUCTION
The requirement for High voltage dc power supplies has become necessary in renewable energy systems, in electric
vehicles, X-rays systems etc. But this could not be met with conventional DC-DC converters because they require
high duty ratio operation, sometimes transformer for stepping up the voltage and also they do not support high
switching frequencies. To reduce the size of the dc-dc converter, one of the solutions is to operate the converter at
high switching frequency so that this results in the small size of the inductor and capacitors. The converters that
switching is controlled by PWM technique are classified into two isolated and non-isolated groups. In the structure
of non-isolated DC-DC converters such as buck, boost, buck-boost, CUK, and SEPIC converters, there is no high
frequency transformer and as a result, non-isolated DC-DC converters have lower price, smaller size and lower
switching losses and high efficiency.
Among non-isolated DC-DC converters, the conventional non-isolated boost converter due to high voltage gain,
direct connection of inductor at input, and lower input capacitance at output and smaller filter size, switch protection
against over voltage and electromagnetic interference(EMI), lower power stress on the elements, higher transient
response ratio, higher efficiency and power density has many applications in LED lighting systems, auxiliary
equipment of hybrid cars and green energy systems such as fuel cell systems, PV systems and WT systems.
In these applications, the non-isolated boost converter acts as an interface between low-voltage sources and high
voltage load and plays an important role in increasing the output voltage gain from low voltage. Assuming that the
converter is ideal in theory, and is in CCM, very high voltage gain would be achieved of a conventional non-isolated
boost converter for high duty cycle ratio. However, due to substantial switching and conduction losses of the diodes
and decrease in efficiency with increase of the voltage gain, especially in high loads, restoring the problem in the
high voltage EMI of elements and high voltage stress of switching, rate of duty cycle is about 0.8 and voltage gain is
almost limited to four times. Therefore, the use of conventional non-isolated boost converters in high voltages would
not be appropriate. To overcome these problems and improve the profile of these converters many methods and
techniques have been presented in recent years. Here, a new structure for non-isolated boost DC-DC converter based
on VL technique is presented that has higher voltage gain. In the followings, equations for elements of the non-
isolated boost DC-DC converter in CCM and DCM are extracted, and the voltage gain and critical inductance
between CCM and DCM for DC-DC converters are calculated. Then, the current stress of switch in CCM and DCM
is evaluated
II. A NOVEL DC-DC BOOST CONVERTER BASED ON VOLTAGE-LIFT TECHNIQUE
Voltage Lift Technique is a popular and effective technique for increasing the output voltage gain that has been used
extensively in the power electronics circuits. Using this technique, characteristics of conventional non-isolated boost
DC-DC converters are well improved. Using this method, the input voltage increases step to step to transfer high
voltage gain to load. The performance of VL technique is based on energy storage elements (inductor and capacitor).
High power density, high efficiency, simple structure and cheapness compared to other techniques and small output
Volume 11 Issue 3 November 2018 61 ISSN: 2319-1058
International Journal of Innovations in Engineering and Technology (IJIET)
http://dx.doi.org/10.21172/ijiet.114.09
voltage ripple, especially for high voltage values are the features of this technique. In addition, the lack of additional
switches that lead to the complexity of the control system of a dc-dc converter is an important feature of this
technique.
The structure of the converter is shown in Figure 3.1. According to Figure 3.1, the structure of the converter consists
of one power switch, two inductors, three capacitors and three diodes. For the convenience of analysis, the following
assumptions are made: (a) The converter is analyzed in the steady state, (b) The output voltage is constant, (c) The
capacitors are large enough, so, the voltage of capacitors is assumed to be constant in each switching cycle, d) The
switch and diodes are ideal. The volt- age and current relations of each element in continuous conduction
mode(CCM)and discontinuous conduction mode(DCM) are determined in the following.
Fig. I: Voltage lift technique based DC-DC converter proposed in [1].
Fig. II: Proposed voltage lift technique based DC-DC boost converter
III. OPERATING PRINCIPLE
Equivalent circuits and the key waveforms of the converter under continuous conduction mode (CCM) is explained
in the following section. The CCM consists of two operating mode including Ton and Toff. The operating modes are
discussed in detail as follows.
3.1. Mode I
In this mode of operation the switch is turned on diodes D1 and D2 are reverse biased. Current flows through both
the inductors. Capacitor C1 is charging and C2, C3 are discharging in nature.
Fig. III: Operating circuit of mode I
Volume 11 Issue 3 November 2018 62 ISSN: 2319-1058
International Journal of Innovations in Engineering and Technology (IJIET)
http://dx.doi.org/10.21172/ijiet.114.09
3.2. Mode II
In this mode of operation the switch is turned on. Diodes D1 and D2 are forward biased. Current flows through both
the inductors. Capacitor C1 is discharging and C2, C3 are charging in nature.
Fig. IV: Operating circuit of mode II
IV. COMPARISON OF DIFFERENT BOOST CONVERTERS
Table I Comparison of different boost converters
Conventional boost converter VL technique based converter Modified VL based converter
No. of diodes 1 3 2
No. Of inductors 1 2 2
No. Of capacitors 1 3 3
Output voltage 24V 36V 35V
Voltage gain 2 3 2.9
Voltage stress
across MOSFET 12V 24V 22V
Voltage ripple 0.12V 0.025V 0.035V
Efficiency 76% 94% 92%
From the above comparison it is evident that the modified converter gives better performance than other converters.
V. DESIGN OF COMPONENTS
In this converter an input voltage of 12V is used and switching frequency is 10 kHz. Load resistance is assumed to
be 100 ohm. Duty ratio of 50 % is chosen.
5.1. Inductor Design
(5.1)
(5.2)
5.2. Capacitor Design
(5.3)
VI. SIMULATION PARAMETERS
Table II Simulation parameters
System parameters Specifications
Duty cycle 50%
Switching frequency 10KHz
Volume 11 Issue 3 November 2018 63 ISSN: 2319-1058
International Journal of Innovations in Engineering and Technology (IJIET)
http://dx.doi.org/10.21172/ijiet.114.09
Input voltage 12V
Inductor L1,L2 1.2Mh
Capacitor C1, C2 110µF
Capacitor C 3 63µF
Load resistance 100Ω
VII. SIMULATION MODEL AND RESULT
Fig. V: Simulation model of the proposed converter
A model of the modified converter is set up and the following waveforms are obtained in Simulink.
Fig.VI shows gate pulse given to switch and voltage stress across switch. Stress across switch is around two third of
the output voltage.
Fig. VI: (a) Gate pulse (b) Voltage stress across switch
Fig.VII shows the current waveforms in continuous conduction mode. Current through inductors never become zero
and thus the continuous mode of operation.
Fig. VII: (a)Current through L1 (b)Current through L2
Volume 11 Issue 3 November 2018 64 ISSN: 2319-1058
International Journal of Innovations in Engineering and Technology (IJIET)
http://dx.doi.org/10.21172/ijiet.114.09
Fig.VIII shows the voltage across C3 which is the output voltage itself.
Fig. VIII: (a)Voltage across C1 (b)Voltage across C2 (c)Voltage across C3
Fig.IX shows the input voltage and output voltage in continuous conduction mode. For an input voltage of 12V, an
output voltage of 33.3V is obtained.
Fig. IX: (a) Output voltage (b) Output current
VIII. ANALYSIS OF THE CONVERTER
(a)
(b)
Fig.X: (a) Voltage gain Vs Duty ratio (b) Voltage ripple Vs duty ratio
The voltage gain and the ripple in output voltage increases with the duty ratio. Above 0.5 duty ratio the voltage
ripple increases beyond the limit.
Volume 11 Issue 3 November 2018 65 ISSN: 2319-1058
International Journal of Innovations in Engineering and Technology (IJIET)
http://dx.doi.org/10.21172/ijiet.114.09
(a)
(b)
Fig. X: (a) Efficiency Vs R Load (b) Efficiency Vs RL Load
The efficiency of the converter is higher with resistive load. Efficiency increases initially and then tends to decrease.
Thus a load resistance of 100Ω is used for optimum efficiency. The efficiency with RL load remains almost constant
with varying inductance.
IX. EXPERIMENTAL SETUP AND RESULTS
The experimental setup of DC-DC boost converter based on voltage lift technique is done through two stages. First
the program is written in micro C for generating gate pulses for switching devices. The program is verified and
frequency is checked by simulating it in the Proteus software. The program is burned to the microcontroller
(PIC16F877A) using the software micro programming suit for PIC. The switches used are MOSFET IRF540 along
with its driver TLP250.
Table II Components used for prototype
Components Rating
Inductors 1.2mH
Capacitor 110µF
Diode IN5819
Controller PIC16F877A
MOSFET IRF540
Driver IC TLP250
A prototype of DC-DC boost converter based on voltage lift technique is implemented. Control pulses for MOSFET
switch is generated using PIC microcontroller. Control pulse is amplified by driver circuit composed of TLP250. It
also provides isolation between control and power circuit. The experimental setup is shown in Fig.XI. It consist of
control circuit, driver circuit and power circuit. Control circuit is composed of PIC microcontroller and its power
supply. The pulses from microcontroller is amplified by driver circuit composed of TLP250. Power circuit the DC-
DC boost converter based on voltage lift technique
Volume 11 Issue 3 November 2018 66 ISSN: 2319-1058
International Journal of Innovations in Engineering and Technology (IJIET)
http://dx.doi.org/10.21172/ijiet.114.09
Fig. XII: Switching pulse waveform
Fig. XI: Experimental setup
Fig. XIII: Output voltage waveform
The converter gives an output of 33.8V. Fig.XIII shows the output voltage waveform DC-DC boost converter based
on voltage lift technique.
X. CONCLUSIONS
A new structure for non-isolated DC-DC boost converters with voltage-lift technique is introduced, its voltage and
current equations of elements and semiconductor devices were extracted in continuous conduction mode and
discontinuous conduction mode, and critical inductance relations were calculated. Following, the structure of
converter and its efficiency was analyzed from the standpoint of number of switches, inductors, capacitors and
diodes, and voltage gain at CCM. Considering Vi=12V, f=12KHz, D=50% and D'=50% , the average load voltage in
CCM mode is 33.3V, which the theoretical and simulated results confirm fairly each other. Given that these voltage
gain is achieved just by only one switch which turned on and turned off by specified duty cycle (dependent on
voltage gain), then special controller system is not required.
Volume 11 Issue 3 November 2018 67 ISSN: 2319-1058
International Journal of Innovations in Engineering and Technology (IJIET)
http://dx.doi.org/10.21172/ijiet.114.09
XI. ACKNOWLEDGMENT
I would like to express my heartfelt gratitude to Prof.Neena Mani, EEE Department, MA College of Engineering,
for providing me guidance and motivation to accomplish my work. She has been very patient and has given me
immense freedom during the course of work. I would also like to thank Prof. Neetha John for her support and
motivation throughout the completion of this work.
XII. REFERENCES
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pp1633-1642, Mar.2017.
[2] N.P. Papanikolaou and E.C. Tatakis, “Active voltage clamp in flyback converters operating in CCM mode under wide load variation", IEEE
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[3] Y.M. Ye and K.W.E. Cheng, “Quadratic boost converter with low buffer capacitor stress", IET Power Electron., vol. 7, no. 5, pp. 1162-
1170, May 2014.
[4] F.L. Luo, Luo-converters, “A series of new dc-dc step-up (boost) conversion circuits", in Proc. Power Electron. and Drive Syst., 1997, pp.
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[5] A.L. Masich, H.V. Blavi, J.M.B. Moncusi and L.M. Salamero, “A high- voltage sic-based boost PFC for LED applications", IEEE Trans.
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[6] F.M. Shahir, E. Babaei, M. Sabahi and S. Laali, \A new dc-dc converter based on voltage lift technique", International Trans. Elec. Energy
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[7] A.L. Masich, H.V. Blavi, J.M.B. Moncusi and L.M. Salamero, “A high voltage sic-based boost PFC for LED applications, IEEE Trans.
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