To design solar (photovoltaic) - Wind hybrid power ... · evaluate the potential of Solar (photovoltaic) –wind hybrid system to produce electricity for a community and other state

International Journal of Emerging Trends & Technology in Computer Science (IJETTCS) Web Site: www.ijettcs.org Email: [email protected], [email protected]

Volume 1, Issue 4, November – December 2012 ISSN 2278-6856

Volume 1, Issue 4 November - December 2012 Page 101

Abstract: In recent year’s generation of electricity using the different types of renewable sources are specifically evaluated in the economical performance of the overall equipment. Solar power & wind power has received considerable attention worldwide. The presented methodology is applied to evaluate the potential of Solar (photovoltaic) –wind hybrid system to produce electricity for a community and other state. Through this hybrid system we have reduce pollution and decrease the global warming. In this we have analyzing the data of wind and solar energy and evaluate the average energy by using hybrid system we have fulfills the energy demand into the future. In future by using of better quality sensor be can increase the potential. We use the small storage capacity. Because maintained cost becomes low using the better quality data logger is can increase the energy production. In future we have to install large solar and wind plant which are cheaper as compared to small plants. The Modeling and simulation of the Solar (photovoltaic) –wind hybrid system is carried out using MATLAB/SIMULINK. Keyword: wind power, solar power, battery, matlab/Simulink.

1. INTRODUCTION Renewable Energy Sources are those energy sources which are not destroyed when their energy is harnessed. Human use of renewable energy requires technologies that harness natural phenomena, such as sunlight, wind, waves, water flow, and biological processes such as anaerobic digestion, biological hydrogen production and geothermal heat. Amongst the above mentioned sources of energy there has been a lot of development in the technology for harnessing energy from the Solar & wind [6]. Solar and wind energy are non-deflectable, site-dependent, non-polluting, and potential sources of alternative energy options. Many countries are pursuing the option of wind energy conversion systems; in an effort to minimize their dependence on fossil-based non-renewable fuels. Also, presently thousands of photovoltaic (PV) deployments exist worldwide, providing power to small, remote, grid-independent or stand-alone applications. For both systems, variations in meteorological conditions (solar irradiation and average annual wind conditions) are important. The performance of solar and wind energy systems are strongly dependent on the climatic conditions at the location. The power generated by a PV system is highly dependent on weather

conditions. For example, during cloudy periods and at night, a PV system would not generate any power. In addition, it is difficult to store the power generated by a PV system for future use. To overcome this problem, a PV system can be integrated with other alternate power sources and/or storage systems, such as electrolyses, hydrogen storage tank, Fuel Cell systems. Combined wind and solar systems are becoming more popular for stand–alone power generation applications, due to advances in renewable energy technologies and subsequent rise in prices of petroleum products. The Economic aspects of these technologies show sufficient promise to include them in developing power generation capacity for developing countries. Research and development efforts in solar, wind, and other renewable energy technologies are required to continue improving their performance, establishing techniques for accurately predicting their output and reliably integrating them with other conventional generating sources [6]. 2. MODELING THE COMPONENTS OF A HYBRID POWER SYSTEM 2.1Modeling the Solar (PV) System A PV generator consists of an assembly of solar cells, connections, protective parts, supports etc. Solar cells are made of semiconductor materials (usually silicon), which are specially treated to form an electric field, positive on one side (backside) and negative on the other (towards the sun). Then solar energy (photons) hits the solar cell, electrons are knocked loose from the atoms in the semiconductor material, creating electron-hole pairs. If electrical conductors are then attacked to the positive and negative sides, forming an electrical circuit, the electrons are captured in the form of electric current (photocurrent) [4].The model of the solar cell can be realized by an equivalent circuit that consists of a current source in parallel with a diode (Fig.1).

Figure 1 Equivalent circuit diagram of a solar cell

To design solar (photovoltaic) - Wind hybrid power generation system

Chitesh Dubey1, Yogesh Tiwari2

1ME Scholar, Department Of Electrical Engg., SSCET Bhilai, India

2Asso. Prof., EEE Department, SSCET Bhilai, India




The p-n junction has a certain depletion layer capacitance, which is typically neglected for modeling solar cells.At increased inverse voltage the depletion layer becomes wider so that the capacitance is reduced similar to stretching the electrodes of a plate capacitor. Thus solar cells represent variable capacitance whose magnitude depends on the present voltage. This effect is considered by the capacitor C located in parallel to the diode [4]. Series resistance RS consists of the contact resistance of the cables as well as of the resistance of the semiconductor material itself. Parallel or shunt resistance RP includes the “leakage currents” at the photovoltaic cell edges at which the ideal shunt reaction of the p-n junction may be reduced. This is usually within the kΩ region and consequently has almost no effect on the current-voltage characteristic [1]. The diode is the one which determines the current-voltage characteristic of the cell. The output of the current source is directly proportional to the light falling on the cell. The open circuit voltage increases logarithmically according to the Shockley equation which describes the interdependence of current and voltage in a solar cell [1].

(1)

(2) Where: k - Boltzmann constant (1.3806 10-23 J/K); T - Reference temperature of solar cell; q - Elementary charge (1.6021 10-19 As); V - Solar cell voltage (V); I0 - saturation current of the diode (A); IPV - Photovoltaic current (A). Equations (1) and (2) lead to the development of a Matlab Simulink model for the PV module presented in Fig. 2.

Figure 2 Matlab Simulink Library PV module. The solar system model consists of three Simulink blocks: the solar model b l oc k , the PV model block and energy conversion modules. The solar model block implements the mathematical model of the solar

radiation. This is done by using standard Simulink and Matlab modules and functions. This block allows selecting different type of patterns for the solar radiation. The PV module implements the equivalent circuit of a solar cell, shown in Fig.1. Standard functions and blocks of Matlab and Simulink were used to obtain this model. Its structure is presented in Fig 3.The output of the PV module is processed by an energy conversion block implemented with a PWM IGBT inverter block from standard Simulink/Sim-Power Systems library [1].

Figure 3 Matlab Simulink implementation of the PV

module

2.2 Modeling the Wind Energy System Modeling the wind energy converter is made considering the following assumptions - Friction is neglected; - Stationary wind flow; - Constant, shear-free wind flow; - Rotation-free flow; - Incompressible flow (q=1.22 kg/m3); - Free wind flow around the wind energy converter On the above condition the maximum physical achievable wind energy conversion can be derived using a theoretical model that is independent of the technical construction of a wind energy converter [1]. The flow air mass has certain energy. This energy is obtained from the air movement on the earth’s surface determined by the difference in speed and pressure. This is the main source of energy used by the wind turbines to obtain electric power [7]. Wind energy systems harness the kinetic energy of wind and convert it into electrical energy or use it to do other work, such as pump water, grind grains, etc. The k inetic energy of air of mass m moving at speed v can be expressed as

(3)

During time period t, the mass (m) of air through a given area A at speed v is:

(4) Where ρ is the density of air (kg/m3). Based on the above two equations, the wind power is




(5) The specific power or power density of a wind site is given as

(6) (a) Power Extracted from Wind. From wind is the difference between the upstream and the down-stream wind powers [7] ) (7) Where v is the upstream wind velocity at the entrance of the rotor blades, v0 is the downstream wind velocity at the exit of the rotor blades. Hm is the mass flow rate, which can be expressed as

)

(8)

Where A is the area swept by the rotor blades. From (7) and (8), the mechanical power extracted by the rotor is given by: (9)

Let (10) We have (11) Cp is called the power coefficient of the rotor or the rotor efficiency. It is the fraction of the upstream wind power, which is captured by the rotor blades and has a theoretical maximum value of 0.59. In practical designs, maximum achievable Cp is between 0.4 and 0.5 for high-speed, two-blade turbines and between 0.2 and 0.4 for low-speed turbines with more blades.[7] A Matlab Simulink model, based on the equations mentioned above, was developed for the wind generator module. This model is shown in Figure 4.

3Conn3

2Conn2

1Conn1

Generator speed (pu)

P itch angle (deg)

Wind speed (m/s)

Tm (pu)

Wind Turbine

Speed

Wind

v+-

Voltage Measurement

mA

B

C

Tm

IG

2

Constant

A B C

<Rotor speed (wm)>

Figure 4 The Matlab Simulink model of the wind turbine Induction generator module.

The Wind Turbine Induction Generator model is much of complicated part of whole simulation model. It consists of Induction Generator & Wind Turbine. Wind Turbine shown in fig.5. The three inputs are the generator speed (ωr_pu) in pu of the nominal speed of the generator, the pitch angle in degrees and the wind speed in m/s. The tip speed ratio λ in pu of λ_nom is obtained by the division of the rational speed in pu of the base rotational speed (defined below) and the wind speed in pu of the base wind speed. The output is the torque applied to the generator shaft.

1Tm (pu)

u (1)^3

wind_sp eed^3

-K-

pu->pu

-K-

p u->pu

-K-

lamb da_nom

lambda

betacp

cp(lambda,beta )

Product

Product

-1

Avoid divi si onby zero

Avoid di vi si onby zero

-K-

1/wind_ base

-K-

1/cp_nom

3Wind spee d

(m/s)

2Pi tch angle (deg )

1Generator speed (pu)

Pwind_puPwind_pu

Pm_puPm_pu

lambdalambdacp_pu

cp_pu

lambda_pulambda_pu

wind_speed_puwind_speed_pu

Figure 4 the Matlab/Simulink implementation of the

wind turbine.

2.3 Modeling the Storage Device Batteries are the basic component of an energy storage system. A battery consists of one or more electrochemical cells that are electrically connected. The basic components of an electrolytic cell like a lead-acid cell are a positive electrode, a negative electrode, a porous separator and an electrolyte. During cell operation, ions are created and consumed at the two electrode/electrolyte interfaces by oxidation/reductions reactions. The electrolyte, which cans either, be a solid or liquid chemical, has high conductivity for ions but not for electrons, because if the electrolyte conducts electrons then the battery will self-discharge. The electrolyte completes the internal circuit between the electrodes. In figure 4.5 the Thevenin equivalent battery model is presented [2].

Figure 6 Thevenin equivalent battery model.

The open circuit voltage, internal capacitor voltage and the terminal voltage are represented by VO, VP and Va. The charging, discharging and the internal




resistance of the battery are represented by Rc, Rd and Rb and the polarization capacitance of the battery is represented by C. The current Ia is taken as positive if discharging and negative otherwise [2]. The equation for the circuit model is:

]

(12)

(13) Based on this model and the equations above, a Matlab-Simulink model was developed for the battery storage device. This model is shown in Figure 4.6.

1vol t

v+-

Voltage Measurement

+

Series RLC Branch3

+

Series RLC Branch2

+

Series RLC Branch1

+

Series RLC Branch

Diode2

Diode

s -+

Controlled Voltage Source

1 In1

Figure 7 The Matlab Simulink model of the battery storage device.

2.4 Solar-Wind Hybrid Power System Using the RegenSim. Library a renewable energy hybrid system shown in Fig.8 . had developed. As shown, the simulation system contains power generation blocks from renewable energy sources such as sun, wind, battery blocks (providing the energy storage), measurements blocks for electrical parameters (voltage, current etc), inverter blocks (for power generation in DC voltage), energy consumer block.

sol ar Volt

Continuous

powergui

In1 v ol t

battery

Conn1

Conn2

Conn3

WTIG1

v+

-

Vab_load1

v+

-

Vab-inv1

g

A

B

C

+

-

Un iversal Bridge3 arms

Te rminator

Solar power

Radiation

Sola r Model

Solar Curren t

Scop e3

Solar Radiation

Measur ements

Power at Load

+

-

Photo voltaic (PV) Model

SPin Sc urrent

SPot

SV olt

+

-

Mesuremen t1Pulses

Discrete PWM Generator

6 pulses

s -+

Control led volt. source

A B C

3-phase lo ad

A

B

C

a

b

c

230V /230V 2M VATra nsfo rmer1

A

B

C

a

b

c

23 0V /230V 2MVATransform er

Vab_load

Vab inv erter

Figure 8 The Matlab Simulink model of the solar-wind

hybrid power generation system.

3. RESULT For the simulation, the data solar irradiance, temperature and wind speed are used. The three data will be the input of the PV and Wind energy generation system. Figure’s shown below show the waveform of the output of the solar and wind energy generation system.

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 11.88

1.89

1.9

1.91

1.92

1.93

1.94

1.95x 10

4

Time (seconds)

sola

rpow

er(W

)

Time Series Plot:

Figure 9 waveform of solar power

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10

50

100

150

200

250

300

Time (seconds)

sola

r vol

tage

(V)

Time Series Plot:

Figure 10 waveform of solar voltage

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1-400

-300

-200

-100

0

100

200

300

400

Time (seconds)

win

d vo

ltage

(V)

Time Series Plot:

Figure 11waveform of generated wind voltage.

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1-3

-2

-1

0

1

2

3x 106

Time (seconds)

win

d ac

tive

& re

activ

e po

wer

Time Series Plot:

Active powerReactive power

Figure 12 waveform of the active and reactive power.




0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1-300

-200

-100

0

100

200

300

Time (seconds)

Vab

inve

rter

Time Series Plot:Vab inverter

Figure 13 waveform of Inverter output voltage

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1-300

-200

-100

0

100

200

300

Time (seconds)

Vab

_loa

d

Time Series Plot:Vab_load

Figure 14 Waveform of the load voltage.

4. CONCLUSION The capitalization of renewable resources potential confers real premises to achieve some strategic aims, but also the durable development of energy sector and the protection of the environment. In order to exploit the economic potential of renewable resources in competitive conditions on the energy market, it is necessary to adopt and implement some energy policies and specific resources. The promotion of energy production from renewable resources represents an imperative objective in present times justified by environment protection, the increase of energetic independence by supplying sources diversity and, of course, economic and social cohesion reasons.

REFERENCES [1]. Dorin Bica, Cristian Dragoç Dumitru, Adrian,

“Isolated hybrid solar–wind-hydro renewable energy systems.” Scientific bulletin of the Petru Maior University of the Targu Mures Vol.7 (XXIV),No.2 2010 ISSN 1841-9267

[2]. Basker Vairamohan,“ State of Charge Estimation Of Batteries.” A thesis presented for the Master of Science Degree, The University of Tennessee, Knoxville.

[3]. M. N. Mansouri Ecole, M. Mansouri Ecole, M.F.Mimouni Ecole, “modeling and c o n t r o l energy management of a hybrid system associated a continuous load and coupled with the electrical network.” International journal of sciences and

techniques of automatic control and computer engineering IJ-STA Vol. 2 No.2 pp 722-727 Dec. 2008.

[4]. Shishir Kumar Pradhan, “Modeling and Simulation of PV array with boost converter: An open Loop Study” A thesis presented for the Bachelor of Technology Degree Department Of Electrical Engineering National Institute Of Technology Rourkela.

[5]. Jinhong Jeon, “Development of A Grid Connected wind/PV/BESS Hybrid Distributed Generation System.” 19th International Conference on Electricity Distribution Vienna 21-24 May 2007 paper 0539

[6]. Shalikram Dewangan, “stability enhancement of a wind energy embedded distribution system” A thesis presented for the Master of Engineering Degree Department Of Electrical Engineering SSCET Junwani Bhilai

[7]. G.D. Rai, “A book of Non conventional energy sources”

Chitesh Dubey received the B.E degrees in Electrical & Electronics Engineering from SSCET, Bhilai in 2007 and Pursing M.E. Degree in Power System Engineering from SSCET, Bhilai. During 2008, he joined as Lecturer in EEE department of

CIT Rajnandgaon. Yogesh Tiwari is currently worked as an Asso. Prof. in EEE Department of SSCET Bhilai. He received the B.E degrees in Electrical Engineering from BIT, Durg in 1997 and M.Tech. Degree in Instrument & Control Engineering from BIT, Durg in 2006. Pursuing

PhD in Electrical Engineering from C.V. Raman University Bilaspur. He has over 4 year industrial & 10 year teaching experience. He has published near 15 research papers in national & international conferences & journals.

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To design solar (photovoltaic) - Wind hybrid power ... · evaluate the potential of Solar (photovoltaic) –wind hybrid system to produce electricity for a community and other state