IJSTE - International Journal of Science Technology & Engineering | Volume 2 | Issue 11 | May 2016
ISSN (online): 2349-784X
Design and Implementation of Super-Lift
Multilevel Inverter using Renewable
Photovoltaic Energy for AC Module Application
Mr. A. Johny Renoald
Assistant Professor
Department of Electrical & Electronics Engineering
Vivekanandha institute of Engineering & technology for
Women, Tiruchengode, Namakkal District-637205.
M. S. Keerthana
PG Scholar
Department of Electrical & Electronics Engineering
Vivekanandha institute of Engineering & technology for
Women, Tiruchengode, Namakkal District-637205.
Abstract
PV installations can operate for 100 years or even more with little maintenance. The solar photovoltaic has the advantage of direct
conversion of sunlight to electricity, So the PV energy is considered as the source for the voltage lift technique. This super-lift
technique is the most outstanding contribution in DC/DC conversion and DC/AC conversion technology. Super -lift Luo converters
can lift the DC input voltage into a higher-level output DC voltage. The increased dc output voltage from super lift luo converter
is converted into ac voltage through super lift multilevel inverter with further increase in voltage. The proposed system can increase
the voltage transfer gain by the super-lift DC/AC converter. When compared with MLI where the harmonic content deteriorates
as the number of levels increases, the super-lift DC/AC converter can reduce the harmonics with reduced the number of levels and
reduced devices. The system design with fuzzy based controllers is proposed for super-lift converters to lift positive input voltage
and output voltage for power quality improvement. The simulation is conceded out by MATLAB/SIMULINK software.
Keywords: PV cells, super lift converter, voltage lift technique, Voltage Transfer Gain, Fuzzy logic controller
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I.
INTRODUCTION
Voltage lift (VL) technique is a popular method widely used in electronic circuit design. It has been successfully employed in
dc/dc converter and dc/ac inverter applications and opened a way to design high voltage gain converters and inverters. There are
three types of MLI structures such as diode clamped, flying capacitor and cascaded H Bridge. The drawback of this converter
topology includes increased number of devices required and control complexity. In the proposed work, super-lift DC/AC converter
is put forth for solar photovoltaic applications which can perform the necessary voltage conversion. They are two types of voltage
lifting technique such as Super lift and Re lifting technique. Fang Lin Luo (2003) introduced “Positive Output Super-Lift and Relift Luo-converters” where the conversion is generally focus on multiple repeating parts, but the proposed system introduces the
development of super- lift multilevel technique which can reduce the repeating components. However, the output voltage increases
in stage by stage just along the arithmetic progression This paper introduces a novel approach—super-lift (SL) technique that
implements the output voltage increasing in stage by stage along the geometric progression. It effectively enhances the voltage
transfer gain in power series. DC-DC conversion technology and DC-AC conversion technology has been developing very rapidly
and have been widely used in industrial applications such as motor drives, computer systems and communication equipments. The
output voltage of pulse width modulation (PWM) based DC-AC multilevel inverters can be changed by changing the duty cycle.
The positive output elementary super lift Luo converter and multilevel inverter is a new series of DC-AC inverters possessing
high-voltage transfer gain, high power density; high efficiency, reduced ripple voltage and current. These converters are widely
used in computer peripheral equipment, industrial applications and switch mode power supply, especially for high voltage-voltage
projects Control for them needs to be studied for the future application of these good topologies. The super-lift technique
considerably increases the voltage transfer gain stage by stage in geometric progression. An approach, positive output elementary
super lift Luo converters, that implements the output voltage increasing in geometric progression with a simple structured have
been introduced. These converters also effectively enhance the voltage transfer gain in power-law terms. Due to the time variations
and switching nature of the power converters, their static and dynamic behavior becomes highly nonlinear. The design of high
performance control for them is a challenge for both the control engineering engineers and power electronics engineers. In general,
a good control for DC-DC converters always ensures stability in arbitrary operating condition. Moreover, good response in terms
of rejection of load variations, input voltage variations and even parameter uncertainties is also required for a typical control
scheme. The static and dynamic characteristics of these converters have been well discussed in the literature.
The fuzzy control technique offers several advantages compared to PID control methods and they are stability, even for large
line and load variations, reduce the steady error, robustness, good dynamic response and simple implementation. In this paper,
state-space model for Positive output elementary Super- lift Luo converter are derived at first and its output is given to the Superlift multilevel inverter and an increased ac voltage is obtained.
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Design and Implementation of Super-Lift Multilevel Inverter using Renewable Photovoltaic Energy for AC Module Application
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A fuzzy control is designed to control the gate signal and reduce the harmonic effect of Super- lift multilevel inverter and the
load is given to the induction motor.
The performance of the system with fuzzy control super lift multilevel inverter is studied in Matlab/ Simulink. Details on
operation, analysis, control strategy and simulation results for super lift multilevel inverter - VSI controlled Induction motor are
presented in the subsequent sections.
The main objective of the project is to design and implementation of super lift DC/AC inverters with positive output super-lift
converter using photovoltaic energy for AC module application and to increase the voltage in geometric progression and to reduce
the harmonic effect. The objectives of this project report are design and implementation of super lift DC/AC converters and to
efficiently increase the voltage.
II. BLOCK DIAGRAM DESCRIPTION
The supply is given to the load (induction motor) through super lift multilevel inverter. The input of the super lift luo converter is
derived from pv source, the super lift luo converter increases the voltage in geometric progression. The increased output voltage
is given as the input to the super lift multilevel inverter the inverter convert dc-ac and the ac is given to the inductive load. The
pwm control the frequency signal of the converter and inverter.
The fuzzy controller is given to contol and reduce the harmonic effect and also control the signal given to the inductive load is
shown in figure 1.
Fig. 1: Block Diagram for super lift inverter with fuzzy controller
III. SUPER-LIFT CONVERTERS
Voltage lift technique has been successfully employed in design of dc/dc converters, e.g., four series Luo converters. However,
the output voltage increases in arithmetic progression. This paper introduces a novel approach super-lift technique that implements
the output voltage increasing in geometric progression. It effectively enhances the voltage transfer gain in power law. This paper
introduces a novel approach super-lift (SL) technique that implements the output voltage increasing in stage by stage along the
geometric progression. It effectively enhances the voltage transfer gain in power series. It largely increases the voltage transfer
gain in power-law. Very high output voltage is easily obtained. Simulation and experimental results This series Luo converter will
be applied in industrial applications with very high output voltage.
Circuit Diagram
Fig. 2: Super lift converter
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Design and Implementation of Super-Lift Multilevel Inverter using Renewable Photovoltaic Energy for AC Module Application
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Equivalent Circuit
Fig.3. Equivalent circuit
The equation can be given as,
V0 =(
2−𝑘
1−𝑘
)Vin
where k is the duty cycle.
The output voltage v0,
V0=(
2−K 2
) Vin
1−K
IV. SUPER LIFT MULTILEVEL DC/AC INVERTERS
The super-lift technique is the most outstanding contribution in DC/DC conversion technology. The source for this inverter is
derived from the solar photo voltaic cell. The solar panel is constructed with a solar cell (or photovoltaic cell), the technology of
which embraces broad multidisciplinary subject areas. It converts solar energy into electricity by the photovoltaic effect. Briefly,
solar cells are divided into two groups: monocrystalline and multicrystalline silicon wafers. shows a mono crystalline silicon wafer
solar cell. Positive output super-lift Luo converters can easily lift the DC input voltage into a higher-level output DC voltage. In
addition, positive output super-lift Luo converters have many subseries and circuits. The voltage transfer gains of the circuits
increase in geometrical series (power series) stage by stage. Therefore, the super-lift technique has attracted much worldwide
attention in recent decades. We were the first to apply super-lift Luo converters in DC/AC inverters. An elementary positive output
super-lift Luo converter is shown in Figure. The equivalent circuits are shown in Figure. when switch S is on and when switch S
is off. When the main switch S is on, the inductor L1 and capacitor C1 are charged by the source voltage Vin. In the steady state,
VC1 = Vin. When the main switch S is off, the output voltage VO is highly lifted from source voltage by inductor L1 and capacitor
C1.
Fig. 4: A fifteen-level super-lift inverter.
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Design and Implementation of Super-Lift Multilevel Inverter using Renewable Photovoltaic Energy for AC Module Application
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Super Lift Conversion Tecnique in Multilevel Inverter:
In this section, we show how to apply the super-lift conversion technique in multilevel DC/AC inverters. And obtained the 15 level
output.
Fifteen -Level Super Lift Inverter:
A 15-level super-lift inverter is shown.One change-over-switch (2P2T) is used in the circuit. When k = 6/7 (≈ 0.857), the output
voltage is 7E. We use seven capacitors, C2, C3, C4, C5, C6, C7, and C8, to split the output voltage in seven levels: E, 2E, 3E, 4E,
5E, 6E, and 7E.
Therefore, the operation status is as follows:
 Vout = 7E: The change-over-switch is on, and the band-switch is at position 7.
 Vout = 6E: The change-over-switch is on, and the band-switch is at position 6.
 Vout = 5E: The change-over-switch is on, and the band-switch is at position 5.
 Vout = 4E: The change-over-switch is on, and the band-switch is at position 4.
 Vout = 3E: The change-over-switch is on, and the band-switch is at position 3.
 Vout = 2E: The change-over-switch is on, and the band-switch is at position 2.
 Vout = E: The change-over-switch is on, and the band-switch is at position 1.
 Vout = 0: The band-switch is at position 0 (i.e., N).
 Vout = −E: The change-over-switch is off, and the band-switch is at position 1.
 Vout = −2E: The change-over-switch is off, and the band-switch is at position 2.
 Vout = −3E: The change-over-switch is off, and the band-switch is at position 3.
 Vout = −4E: The change-over-switch is off, and the band-switch is at position 4.
 Vout = −5E: The change-over-switch is off, and the band-switch is at position 5.
 Vout = −6E: The change-over-switch is off, and the band-switch is at position 6.
 Vout = −7E: The change-over-switch is off, the band-switch is at position 7.
We have obtained a 15-level output AC voltage. The output voltage peak value is seven times the input DC voltage E. The
waveform is shown.
Fig. 5: A fifteen-level super-lift inverter waveform.
Design of Fuzzy Logic Controller for Super Lift Multilevel Inverter.
Fuzzy control can be used to improve existing traditional controller systems by adding an extra layer of intelligence to the current
control method. The process of converting a crisp input value to a fuzzy value is called "fuzzification". The fuzzy controller utilizes
triangular membership functions on the controller input. The triangular membership function is chosen for its simplicity. Fuzzy
control rules are obtained from the analysis of the system behavior. The operating condition greatly improve the converter
performance in terms of dynamic response and robustness. To obtain the control decision the minimax inference method is used.
The rule viewer for the fuzzy logic controller is shown in figure‐5.
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Design and Implementation of Super-Lift Multilevel Inverter using Renewable Photovoltaic Energy for AC Module Application
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Fig. 6: Rule Viewer
V. SIMULATION DIAGRAM AND RESULTS
PV Cell System
The photovoltaic systems are comprised of photovoltaic cells, devices that convert light energy directly into electricity. PV cells
convert sunlight directly into electricity without creating any air or water pollution.
Fig.7. PV Simulation
PV cells are made of at least two layers of semi-conductor material. One layer has a positive charge, the other negative. When
light enters the cell, some of the photons from the light are absorbed by the semiconductor atoms, freeing electrons from the cell’s
negative layer to flow through an external circuit and back into the positive layer. This flow of electrons produces electric current.
The stand-alone photo-voltaic energy system requires storage to meet the energy demand during period of low solar irradiation
and night time. The short circuit open current from the pv cell is 10A and the open circuit voltage is 80v. The solar panel is
constructed with a solar cell (or photovoltaic cell), the technology of which embraces broad multidisciplinary subject areas. It
converts solar energy into electricity by the photovoltaic effect. Briefly, solar cells are divided into two groups: monocrystalline
and multicrystalline silicon wafers.
Simulation of Super Lift LUO Converters
An dc voltage is generated from the pv cell. The super lift converter in this project increases the voltage generated from solar stage
by stage in arithmetic progression.
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Fig. 8: simulation diagram of super lift luo converter
VI. SIMULATION OF SUPER LIFT MULTILEVEL DC/AC INVERTER
The increased dc voltage from super lift luo converter is fed to the super lift multilevel inverter and it converte dc to ac
voltage. The 15 level ac output voltage is obtained from super lift inverters.obtained satisfactory simulation and experimental
results. These super-lift multilevel inverters can also be used in other renewable energy systems and industrial applications.
Fig. 9: Simulation Diagram of Super Lift Inverter
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Design and Implementation of Super-Lift Multilevel Inverter using Renewable Photovoltaic Energy for AC Module Application
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Fig. 10: Tabulation of parameters
VII. RESULTS
The positive output triple luo converter is designed with multilevel dc/ac inverter developed using fuzzy logic controller in
MATLAB/Simulink and the output voltage from converter with and without fuzzy logic controller. When load resistance increased
the settling time is reduced. When load resistance decreased the settling time increased.
Fig. 11: output voltage from super lift luo converters
Fig. 12: Output Voltage from super lift multilevel inverter
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VIII. CONCLUSION
In this paper the new topology super lift inverters are designed and implemented by using photovoltaic energy as a source. The
key advantages of this topology compared to the conventional topologies include reduced number of devices and increase the
voltage. The paper includes both super lift converter and inverter. A novel modulation technique is proposed for multilevel voltage
source inverter and simulated in the MATLAB/SIMULINK environment and its performance parameters are analyzed for different
levels of multilevel inverter. The output parameter increased 15 level ac voltage is analyzed. The super lift multilevel inverters for
different levels are modelled in the MATLAB/SIMULINK environment. The super lift inverter is the best choice when compared
to other inverter topologies due to the absence of the input voltage unbalance and freewheeling diodes. In the super lift multilevel
inverter configuration, the output is obtained in fifteenth level and the output percentage THD is controlled by using fuzzy
controller. The output is connected to the three phase AC induction motor as the load. The three phase voltage of 600 Volts AC is
obtained across the output terminals for the DC input of 320 Volts. The harmonics is also reduced for the different load conditions
of the three phase induction motor. The implementation of the proposed technique increases the voltage and obtains different pulse
level of ac voltage. It reduces the harmonics significantly.
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