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Australian Journal of Basic and Applied Sciences

AUSTRALIAN JOURNAL OF BASIC AND

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To Cite This Article: Mr.M.Chilambarasan andConverter Topologies. Aust. J. Basic & Appl. Sci.,

Simulation and Comparison of CukTopologies 1Mr.M.Chilambarasan and 2Dr.M.Ramesh Babu

1Assistant Professor Professor St. Joseph’s College of Engineering Address For Correspondence: Mr.M.Chilambarasan, Assistant Professor Professor St. Joseph’s College of Engineering Chennai, IndiaE-mail: [email protected] A R T I C L E I N F O Article history: Received 12 January 2016 Accepted 22 February 2016 Available online 1 March 2016 Keywords: Cuk converter, Sepic Converter,Buck Converter,Photovoltaic systems, Wind Turbine

Recent developments and trends in the electric power consumption indicate an increasing use of renewable

energy. Virtually all regions of the world have renewable resources of one type or another. By this point of view studies on renewable energies focusesrenewable energy sources most common in use. Wind energy has become the least expensive renewable energy technology in existence and has peaked the interest of scientists and educators and K. Kalaitzakis, 2006). Photovoltaic cells convert the energy from sunlight into DC electricity. PVs offer added advantages over other renewable energy sources in that they give off no noise and require practicamaintenance (Shu-Hung et al., 2003power generation.

Many studies have been carried out on the use of renewable energy sources for power generation and many papers were presented earlier. The wunpredictable nature. In (Wies et alanalyze the reduction in the fuel consumed. It was seen that the incorporationcan further reduce the fuel consumption. When a source is unavailable or insufficient in meeting the load demands, the other energy source can compensate for the difference. Several hybrid wind/PV power systems with Maximum Power Point Tracking (MPPT) control have been proposed earlier Mohammed Aslam Husain, Abu Tariq, 2013connected in fusion in the rectifier stage to perform the MPPT control

Australian Journal of Basic and Applied Sciences, 10(5) Special 2016, Pages: 103-110

AUSTRALIAN JOURNAL OF BASIC AND

APPLIED SCIENCES

ISSN:1991-8178 EISSN: 2309-8414 Journal home page: www.ajbasweb.com

© 2016 AENSI Publisher All rights reserved This work is licensed under the Creative Commons Attribution International License (CC BY).

http://creativecommons.org/licenses/by/4.0/

Mr.M.Chilambarasan and Dr.M.Ramesh Babu., Simulation and Comparison of Cuk-Aust. J. Basic & Appl. Sci., 10(5): 103-110, 2016

Comparison of Cuk-Sepic and Cuk-Buck Fused

Dr.M.Ramesh Babu

St. Joseph’s College of Engineering Chennai, India.

Assistant Professor Professor St. Joseph’s College of Engineering Chennai, India

A B S T R A C T Power supply systems all over the world are facing challenging situations where they have to be extremely flexible, reliable and expandable.comparison of a new system configuration of the front- end rectifier stage for a hybrid wind-photovoltaic energy system: Cuk-Sepic and Cuk-Buck .This configuration allows the two sources to supply the load separately or simultaneously together depending on the availability of the energy sources. The main purpose of this hybrid windenergy system is to meet our daily demand effectively and to get an uninterrupted power supply from any one of the natural source either wind or solar or both. Due to the inherent nature of these fused converters, additional filters are not necessary to filter out high frequency harmonics.Also the values of inductance and capacitance are less for Cuk Buck converter than the Cuk Sepic converter. But Cuk Sepic converter has more number of components compared to Cuk Buck converter. these fused converters are high efficiency, reduced component count, simple control and flexibility in power sharing. Simulation results are given to highlight the merits of these converters.

INTRODUCTION

Recent developments and trends in the electric power consumption indicate an increasing use of renewable energy. Virtually all regions of the world have renewable resources of one type or another. By this point of view studies on renewable energies focuses more and more attention. Solar energy and wind energy are the two renewable energy sources most common in use. Wind energy has become the least expensive renewable energy technology in existence and has peaked the interest of scientists and educators over the world

. Photovoltaic cells convert the energy from sunlight into DC electricity. PVs offer added advantages over other renewable energy sources in that they give off no noise and require practica

., 2003). Hybridizing solar and wind power sources provide a realistic form of

Many studies have been carried out on the use of renewable energy sources for power generation and many papers were presented earlier. The wind and solar energy systems are highly unreliable due to the

et al., 2005), a PV panel was incorporated with a diesel electric power system to analyze the reduction in the fuel consumed. It was seen that the incorporation of an additional renewable source can further reduce the fuel consumption. When a source is unavailable or insufficient in meeting the load demands, the other energy source can compensate for the difference. Several hybrid wind/PV power systems

um Power Point Tracking (MPPT) control have been proposed earlier Mohammed Aslam Husain, Abu Tariq, 2013). They used a separate DC/DC buck and buckconnected in fusion in the rectifier stage to perform the MPPT control for each of the renewable energy power

110

-Sepic and Cuk-Buck Fused

Buck Fused Converter

Power supply systems all over the world are facing challenging situations where they reliable and expandable. This paper presents a

end rectifier stage for a hybrid Buck .This configuration allows

arately or simultaneously together depending on the availability of the energy sources. The main purpose of this hybrid wind-solar energy system is to meet our daily demand effectively and to get an uninterrupted

urce either wind or solar or both. Due to the inherent nature of these fused converters, additional filters are not necessary to filter out

Also the values of inductance and capacitance are less for Sepic converter. But Cuk Sepic converter has more

The highlighting features of ficiency, reduced component count, simple control

on results are given to highlight the merits of

Recent developments and trends in the electric power consumption indicate an increasing use of renewable energy. Virtually all regions of the world have renewable resources of one type or another. By this point of view

more and more attention. Solar energy and wind energy are the two renewable energy sources most common in use. Wind energy has become the least expensive renewable energy

the world (Koutroulis, E. . Photovoltaic cells convert the energy from sunlight into DC electricity. PVs offer

added advantages over other renewable energy sources in that they give off no noise and require practically no . Hybridizing solar and wind power sources provide a realistic form of

Many studies have been carried out on the use of renewable energy sources for power generation and many ind and solar energy systems are highly unreliable due to their

, a PV panel was incorporated with a diesel electric power system to of an additional renewable source

can further reduce the fuel consumption. When a source is unavailable or insufficient in meeting the load demands, the other energy source can compensate for the difference. Several hybrid wind/PV power systems

um Power Point Tracking (MPPT) control have been proposed earlier (Chen et al., 2007; They used a separate DC/DC buck and buck- boost converter

for each of the renewable energy power

104 Mr.M.Chilambarasan and Dr.M.Ramesh Babu, 2016 Australian Journal of Basic and Applied Sciences, 10(5) Special 2016, Pages: 103-110

sources (Chen, Y.-M., S.-C Hung, 2005). These systems have a problem that, due to the environmental factors influencing the wind turbine generator, high frequency current harmonics are injected into it. Buck and buck-boost converters do not have the capability to eliminate these harmonics. So the system requires passive input filters to remove it, making the system more bulky and expensive (Chen et al., 2007).

In this paper, a new converter topology for hybridizing the wind and solar energy sources has been proposed. In this topology, both wind and solar energy sources are incorporated together using a combination of Cuk - SEPIC converters and Cuk- Buck Converters, so that if one of them is unavailable, then the other source can compensate for it. These fused converters have the capability to eliminate the HF current harmonics in the wind generator. This eliminates the need of passive input filters in the system. These converters can support step up and step down operations for each renewable energy sources. They can also support individual and simultaneous operations. Solar energy source is the input to the Cuk converter and wind energy source is the input to the SEPIC converter. The average output voltage produced by the system will be the sum of the inputs of these two systems. All these advantages of the proposed hybrid system make it highly efficient and reliable.

Modelling Of Pv Panel:

Photovoltaic (PV) systems have been used for many decades. Today, with the focus on greener sources of power, PV has become an important source of power for a wide range of applications. A photovoltaic cell is comprised of a P-N junction semiconductor material such as silicon that produces currents via the photovoltaic effect. When light energy strikes the solar cell, electrons are knocked loose from the atoms in the semiconductor material. If electrical conductors are attached to the positive and negative sides, forming an electrical circuit, the electrons can be captured in the form of an electric current. This electricity can then be used to power a load. Due to the low voltage generated in a PV cell (around 0.5V), several PV cells are connected in series (for high voltage) and in parallel (for high current) to form a PV module for desired output. The standard equivalent circuit of the PV cell is shown in Fig.1.

Fig. 1: Equivalent circuit of the PV cell

The current output of PV module is

Ipv=NpIph-NpIs[exp{q(Vpv+IpvRs)/NsAkT}-1] (1)

where Ipv is the photovoltaic current and Np is the number of cells connected in parallel. In fact, the PV

efficiency is sensitive to small change in Rsbut insensitive to variation in Rsh. (Mr.M.Chilambarasan, et al., 2014) Modelling Of Wind Turbine:

The wind turbine is the first and foremost element of wind power systems. Wind turbines capture the power from the wind by means of aerodynamically designed blades and convert it to rotating mechanical power (Chen, Y.-M., S.-C Hung, 2005). The number of blades is normally three. This mechanical power is delivered to the rotor of an electric generator where this energy is converted to electrical energy. Electric generator used may be an induction generator or synchronous generator.

The mechanical power that is generated by the wind is given by: Pm =0.5�� (λ,β)CpVw

3 (2) Where ρ - air density, A - rotor swept area, Cp (λ, β) - power coefficient function, λ - tip speed ratio, β -

pitch angle, w -wind speed. The maximum value of Cpis 0.48 at β = 0 and λ = 0.16. The wind turbine model is connected to a squirrel cage asynchronous generator. The mechanical energy

obtained from the wind turbine is fed to the generator, which convert it to the electrical energy.

105 Australian Journal of

Fig. 2: Power Coefficient curve for a

Maximum Power Point Tracking: The disadvantage of the perturb and observe method to track the peak power under fast varying atmospheric

condition is overcome by IC method. The IC can determine that the MPPT has reached the MPP and sperturbing the operating point. If this condition is not met, the direction in which the MPPT operating point must be perturbed can be calculated using the relationship between dl/dV and from the fact that dP/dV is negative when the MPPT is to the right of the MPP and positive when it is to the left of the MPP. This algorithm has advantages over P&O in that it can determine when the MPPT has reached the MPP, where P&O oscillates around the MPP. Also, incremental conducdecreasing irradiance conditions with higher accuracy than P and O.

Fig. 3: P-V array power curve Fig-3 shows that the slope of the P

MPP and decreasing on the Right hand side of the MPP. The basic equations of this method (Srushti R. Chafle, Uttam B. Vaidya, 2013

��

��

�

��

��

��

�

��

��

��

�

��

Cuk Sepic Converter:

PV array is the input to the Cuk converter and wind source is the input to the Jacob, 2012). The converters are fused together by reconfiguring the two existing diodes from each converter and the sharing the Cuk output inductor by the SEPIC converter. This configuration allows each converter to operate normally individually in the event that one source is unavailable. When only wind source is available, the circuit operates as a SEPIC converter and the voltage conversion relationship is given by:��

�� /�1 � ��

Mr.M.Chilambarasan and Dr.M.Ramesh Babu, 2016 Australian Journal of Basic and Applied Sciences, 10(5) Special 2016, Pages: 103-

Power Coefficient curve for a typical wind turbine

The disadvantage of the perturb and observe method to track the peak power under fast varying atmospheric

condition is overcome by IC method. The IC can determine that the MPPT has reached the MPP and sperturbing the operating point. If this condition is not met, the direction in which the MPPT operating point must be perturbed can be calculated using the relationship between dl/dV and –I/V This relationship is derived

gative when the MPPT is to the right of the MPP and positive when it is to the left of the MPP. This algorithm has advantages over P&O in that it can determine when the MPPT has reached the MPP, where P&O oscillates around the MPP. Also, incremental conductance can track rapidly increasing and decreasing irradiance conditions with higher accuracy than P and O.

shows that the slope of the P-V array power curve is zero at The MPP, increasing on the left of the MPP and decreasing on the Right hand side of the MPP. The basic equations of this method Srushti R. Chafle, Uttam B. Vaidya, 2013)

PV array is the input to the Cuk converter and wind source is the input to the SEPIC converter. The converters are fused together by reconfiguring the two existing diodes from each converter

and the sharing the Cuk output inductor by the SEPIC converter. This configuration allows each converter to individually in the event that one source is unavailable. When only wind source is available,

the circuit operates as a SEPIC converter and the voltage conversion relationship is given by:

110

The disadvantage of the perturb and observe method to track the peak power under fast varying atmospheric condition is overcome by IC method. The IC can determine that the MPPT has reached the MPP and stop perturbing the operating point. If this condition is not met, the direction in which the MPPT operating point

I/V This relationship is derived gative when the MPPT is to the right of the MPP and positive when it is to the left

of the MPP. This algorithm has advantages over P&O in that it can determine when the MPPT has reached the tance can track rapidly increasing and

V array power curve is zero at The MPP, increasing on the left of the MPP and decreasing on the Right hand side of the MPP. The basic equations of this method are as follows.

(3)

(4)

(5)

SEPIC converter (Teena . The converters are fused together by reconfiguring the two existing diodes from each converter

and the sharing the Cuk output inductor by the SEPIC converter. This configuration allows each converter to individually in the event that one source is unavailable. When only wind source is available,

the circuit operates as a SEPIC converter and the voltage conversion relationship is given by:

(6)


When only PV source is available, the circuit acts as a Cuk converter and the voltage conversion is given by: ��

� != �"/(1 − �") (7)

Fig. 4: Cuk Sepic Converter

Modes Of Operation:

Fig. 5: Mode 1 : M1 &M2 on

Fig. 6: Mode 2 : M1 on & M2 off


Fig. 7: Mode 3 : M1 off&M2 on

Fig. 8: Mode 1 : M1 &M2 off Cuk Buck Converter:

Solar fed cuk converter and wind fed buck converter are fused resulting in a Cukeliminating the need of various dc/dc converters for each sourceoutput voltage produced by the system will be the sum of the inputs of these two systems. Both wind and solar energy sources are incorporated together using a combination of cuk and buck converters. The cukconverters support step up and step down operations for each renewable energy sources with individual and simultaneous operations. By applying parallel power conversion technique to the cukefficiency can be improved. All these advantages oreliable.

Fig. 9: Cuk Buck Converter

Modes of operation:


Solar fed cuk converter and wind fed buck converter are fused resulting in a Cukeliminating the need of various dc/dc converters for each source (Renugadevi, V1, et aloutput voltage produced by the system will be the sum of the inputs of these two systems. Both wind and solar energy sources are incorporated together using a combination of cuk and buck converters. The cuk

s support step up and step down operations for each renewable energy sources with individual and simultaneous operations. By applying parallel power conversion technique to the cuk-buck fused topology, the efficiency can be improved. All these advantages of the proposed hybrid system make it highly efficient and

110

Solar fed cuk converter and wind fed buck converter are fused resulting in a Cuk-Buck fused converter et al., 2014). The average

output voltage produced by the system will be the sum of the inputs of these two systems. Both wind and solar energy sources are incorporated together using a combination of cuk and buck converters. The cuk- buck fused

s support step up and step down operations for each renewable energy sources with individual and buck fused topology, the

f the proposed hybrid system make it highly efficient and


Fig. 10: Mode 1 : M1 &M2 on

Fig. 11: Mode 2 : M1 on& M2 off

Fig. 12: Mode 3 : M1 off &M2 on


110


Fig. 13: Mode 4 : M1 & M2 off

Simulation Results:

Fig. 14: Cuk sepic Converter

Fig. 15: Cuk Buck Converter Table I: Comparison Of Output Voltages

CONVERTER Cuk Sepic Converter Cuk Buck Converter

For V1=12V,Duty cycle=50%,Frequency= 25KHz

0 0.111

12

13

Vol

tage

(V)

0 0.111

12

13

Vol

tage

(v)

0 0.1-50

0

50

Vol

tage

(V)

0 0.1-2

-1

0

1

Cur

rent

(A)

0 0.111

12

13

Vol

tage

(V)

0 0.111

12

13

Vol

tage

(V)

0 0.1-30

-20

-10

0

Vol

tage

(V)

0 0.1-3

-2

-1

0

Cur

rent

(A)


OUTPUT VOLTAGE -24 V

-17 V

cycle=50%,Frequency= 25KHz

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9Time(sec)

Input Voltage (Vpv)

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9Time(sec)

Input Voltage(Vw)

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9Time(sec)

Output Voltage (V)

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9Time(sec)

Output Current (A)

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9Time(sec)

Input Voltage (Vpv)

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9Time(sec)

Input Voltage(Vw)

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9Time(sec)

Output Voltage(V)

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9Time(sec)

Output Current (A)

110

1

1

1

1

1

1

1

1


Table II: Comparison Ofcomponent Ratings COMPONENTS

CUK-SEPIC CONVERTER

CUK-BUCK CONVERTER

L1

10 mH

10 mH

L2

10 mH

0.4 mH

LO

1.6 mH

-

C1

0.1 mF

0.1 mF

C3

0.15 mF

-

CO

0.15 mF

10 µF

Conclusion:

In this paper Cuk Sepic and Cuk buck fused converter topologies have been compared and analyzed. Both these topologies have been modelled, and simulated, to test their performance. For the same value of duty cycle increased output voltage is obtained for Cuk Sepic converter compared to the Cuk Buck converter. Also the values of inductance and capacitance are less for Cuk Buck converter than the Cuk Sepic converter .But Cuk Sepic converter has more number of components compared to Cuk Buck converter. The effects of parasitic elements are overcomed effectively which ultimately increases the output voltage of these fused converters. MPPT algorithm tracks the maximum power from the sun. Incremental Conductance method is widely used to compute the maximum power and to control the extracted power from the PV by changing the duty cycle. Thus these converters are used for various photovoltaic applications also.

REFERENCES

Koutroulis, E. and K. Kalaitzakis, 2006. “Design of a Maximum Power Tracking System for Wind-Energy-

Conversion Applications”, IEEE Transactions on Industrial Electronics, 53(2). Shu-Hung et al., 2003. “A Novel Maximum Power Point Tracking Technique for Solar Panels Using a

SEPIC or Cuk Converter”, IEEE Transactions on Power Electronics, 18(2). Wies et al., 2005. “Simulink Model for Economic Analysis and Environmental Impacts of a PV with

Diesel- Battery System for Remote Villages”, IEEE transactions on Power Systems, 20(2). Chen et al., 2007. “Multi-Input Inverter for Grid-Connected Hybrid PV/Wind Power System”, IEEE

Transactions on Power Electronics, 22. Mohammed Aslam Husain, Abu Tariq, 2013. “Modeling of a standalone Wind-PV Hybrid generation

system using MATLAB/SIMULINK and its performance analysis”, International Journal of scientific & Research, 2: 11.

Chen, Y.-M., S.-C Hung, 2005. (2.4. Cheng, and Y.-C. Liu “Multi-Input Inverter for Grid-Connected Hybrid PV/Wind Power System”2005 IEEE.

Mr.M.Chilambarasan, M. Latha Devi, Dr.M. Ramesh Babu, 2014. ”Design and Simulation of Self Lift Positive Output luo converter using Incremental Conductance Algorithm for Photovoltaic Applications “Applied Mechanics and Materials, 622: 51-58 © (2014) Trans Tech Publications, Switzerland

Srushti R. Chafle, Uttam B. Vaidya, 2013. ”Incremental Conductance MPPT Technique FOR PV System”International Journal of Advanced Research in Electrical, Electronics and Instrumentation Engineering, 2: 6.

Teena Jacob, 2012. Arun S ‘Modelling of Hybrid Wind and photovoltaic Energy System using a new converter Topology’Electrical and Electronics Engineering: An International Journal (EEEIJ) 1(2).

Renugadevi, V1, Margaret Amutha.W2, Dr. Rajini.V3, 2014. “A Novel Improved Fused Converter Based Hybrid System with MPPT Control for Rural Telephony”,International Journal of Emerging Technology and Advanced Engineering, 4: 5.

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