Design, Development and Hardware Realization of X-beebased Single Axis Solar Tracking System

7/30/2019 Design, Development and Hardware Realization of X-beebased Single Axis Solar Tracking System

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International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 6545(Print), ISSN

0976 6553(Online) Volume 3, Issue 3, October December (2012), IAEME

8

DESIGN, DEVELOPMENT AND HARDWARE REALIZATION OF X-BEE

BASED SINGLE AXIS SOLAR TRACKING SYSTEM

ABSTRACT

The objective of this paper to optimize the solar energy receivers. In this paper, a low cost suntracking system is designed using simple gear system and control circuitry, the electronic circuit

diagram with detailed description and performance of the tracking system are presented.Emphasize increased energy produced compare to the fixed system, in the control circuitry weare using X-bee device, the tracking mechanism has proved to be sufficiently accurate for thepresent solar energy application. The position of sun is successfully detected with an accuracy of0.60.

Index Terms- Dc-motor drives, Electronic controlled tracking system, X-bee, Solar trackingsystem, Photovoltaic.

I. INTRODUCTIONHE Sun sends an almost unimaginable amount of energy towards Planet Earth around10 17 Watt. The Suns power density (i.e. the power per unit area normal to its rays) just above

the Earth s atmosphere is known as the solar constant and equals 1366 W/m2.It is reduced by

approximately 0.30 times solar constant as it passes through atmosphere and at earth surface its

value is 1000 W/m2 at sea level on a clear day. In cloudy sky, there could be a small component

of direct radiation and a substantial component of diffuse radiation [1-4].Yet the Sun is an

Neeraj Tiwari1, D. Bhagwan Das2, Prabal Pratap Singh31,2Dayalbagh Educational Institute (Deemed University), Agra

Email: [email protected], [email protected]

T

INTERNATIONAL JOURNAL OF ELECTRICAL ENGINEERING &

TECHNOLOGY (IJEET)

ISSN 0976 6545(Print)

ISSN 0976 6553(Online)

Volume 3, Issue 3, October - December (2012), pp. 08-20

IAEME: www.iaeme.com/ijeet.asp

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amazing benefactor. To extract useable electricity from the sun was made possible by thediscovery of the photoelectric mechanism via a semiconductor device which converts photon

energy into electrical energy.

In order to optimize the solar energy and to produce maximum power output, Solar tracker is

invented because solar panel disables to move toward the sunlight when the sun moves

from east to west. Hession and Bonwick [5] have presented a detailed description of an electro-mechanical sun tracker system they was using phototransistors.

Ayala, J. Kenneth [6] presented, Microprocessors and microcontrollers are widely used inembedded system products. In order to produce maximum power output, solar tracker is design

with 12 Volt DC motor so that solar panel can track the position of sun and it works with sensors

and control circuitry. Solar tracker has many types but we use active trackers. In this paper work,

X-bee based dual axis solar tracking system is designed and developed for maximize the solar

energy because compared to a fixed mount, a single axis tracker increases annual output by

approximately 30%, and a dual axis tracker an additional 6%. There are two types of dual axis

trackers, polar and altitude-azimuth. [7]. the accuracy of this tracking system is much greaterthan the suggested accuracy.

II. SUN TRAJECTORY CALCULATION:LITERATURE REVIEWThe position of sun in the sky varies both with the elevation and the time of the day as the sun

moves from east to west. Therefore solar tracker system can increase solar power over any fixed

solar system. To produce maximum output power requires a great accuracy, one must first be

able to predict the location of the sun relative to a tracking system [8].

We are using vector approach for necessary equation.

15( 12) deg .h sA t in rees=

Where: hA - Angular distance between the meridian of the

Observer and the meridian whose plane contains the sun (-180,180 degrees).

dt - Difference between mean solar time and solar time.

0.258cos 7.416sin 3.648cos2 9.228sin2 mindt in utes = Where: the angle is defined as the

function of day dn .

360( 1)

deg .365d

n

in rees

=

Time conversion:

Local clock time can be calculated as.

.60

dl s c

tt t L in hours= +

Where: st - solar time in minutes.


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cL - Longitude correction can be calculated as.

( ).

15t

c

local longitude zL in hours

=

tan .t s dard longitudeztime zone meridain

=

Fig.1. Sun position calculation

The Declination Angle ( dA ):

This is the angle between line (joining the center of the earth and the sun) and the earths

equatorial plane. 1sin [0.3979 cos {0.98563( 173)}] deg .d d

A n in rees

= Where: dn -Number of

days.

Solar Altitude Angle ():

This is the angle between solar ray and observer plane as shown in Fig.1.

1

sin sin .sin cos .cos .cos

sin (sin .sin cos .cos .cos ).

d d h

d d h

A A A

A A A

=

=

Where: hA - Hours Angle.

dA - Declination Angle.

Zenith Angle (): Complement of the solar altitude angle () as shown in Fig.1.

i

k

East

North

Zenith

Sz

Sj Sk

SUN


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90 = .

Azimuth Angle ():

From Fig.1.all the angles are in degrees Azimuth angle can be represented as.

1

cos .cos sin .cos cos .cos .sin .(sin .cos cos .cos .sin )

coscos

(sin .cos cos .cos .sin )cos

cos

d d h

d d h

d d h

A A AA A A

A A A

=

=

=

III. MECHANICAL DESIGNA tracking system must be reliable and able to follow the sun with a certain degree of accuracy,the tracking systems can be divided into two broad categories, namely electrical/electronic

systems [9] and mechanical systems [10].

Mechanical structure for solar tracking system is shown in Fig.2 and Fig.3. In our experimental

setup we are using two 12 volt PMMC DC motor to rotate 510 watt for dual axis tracking.

Fig. 2.Experimental set up


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Fig. 3 Electronic circuit for single axis tracking

IV. SYSTEM DESIGN:SOLAR TRACKINGWe are using 12Volt two dc motors to rotate three 170watts panel each mounted on themechanical structure from east to west. The mechanical structure of open loop solar tracking

system is shown in fig.1 and 2. Here we are using Zig-bee base tracking system, it requires

control circuitry used to rotate the two pmmc type 12V motor for dual axis tracking system.Earth rotate in elliptical orbit around the sun and also around in own axis known as polar axis,

mathematically declination angle (Z

) can be expressed as [10].

nd = day of the year.

0 360.( 180)23.45 .sin365

dZ

n =

If Z is the zenith angle then: Z = .

Where = latitude angle.

Z = declination angle.

Fig.3 position of earth with respect to sun

Solar Event Date

Vernal equinox Mar-21

Summer solstice June-21

Autumnal equinox Sep-23

Winter solstice Dec-21


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The azimuth angle is zero at solar noon and increases toward the east. The angle about thevertical axis is called the azimuthal angle and is 0 at due south and becomes positive as you start

to point east. The angle about the horizontal axis is called the altitude and is 0 level to the

horizon and becomes positive as you point towards the sky.

Fig. 4: Solar Trajectory

V. CALCULATION:SOLARRADIATIONSolar radiation energy availability is vital for utilization of PV systems. The higher the

availability of solar radiation energy, the smaller will be the size of the PV array that makesthe cost of PV system cheaper. Solar energy is radiated uniformly in all the direction the

spectrum of this radiation lies in the visible and infrared part of the EM (Electromagnetic) wave.

The luminosity of the Sun is about 3.86 x 1026 watts. The distance of the sun from the earth is

150 million kilometer and the earth radius is 63000 kilometer approximately. The solar powerwe received at the earth surface is approximately 1370 watts per square meter is called solar

constant. It is varies by +/- 3% because of the Earth's slightly elliptical orbit around the Sun as

shown in fig.4. Therefore the extra-atmospheric radiation EAR varies according to the law:

[1 0.33.cos(360. 365)]d

EAR Sc n= +

Where Sc - solar constant, dn - represents the day of the year considered, counted from January

1.table2 shows the day to day conversion [11].


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Month Day Number, nd Notes

January d *

February d+31 *

March d+59 Add 1 if leap year

April d+90 Add 1 if leap year

May d+120 Add 1 if leap year

June d+151 Add 1 if leap year

July d+181 Add 1 if leap year

August d+212 Add 1 if leap year

September d+243 Add 1 if leap year

October d+273 Add 1 if leap year

November d+303 Add 1 if leap year

December d+334 Add 1 if leap yearTable 2

The radiation at the earth surface in clear sky condition

T dir diff reflRA RA RA RA= + +

Fig.5: Global Radiation on Inclined Plane

dirRA - Direct component of solar radiatio on a surface can be calculated.

( )0 .cos cos 0exp( / sin )

dir

EARRA if

= >

Where: 0EAR = extra atmospheric radiation if the origin of the rays had zenithal. It can be

calculated for each day of the year by the formula:

0 1150.65 72.43.cos(0.95. ) 34.25.sin(0.017. ) 1.5log( )d d dEAR n n n= + + + = endangered atmosphere coefficient.

It is:


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4 2 6 3 9 41(6.74 0.026. 5.1314 . 2.24.10 . 2.80.10 . )

d d d d n n n n

=+ + +

The diffusion component on the same area:

0 .exp( / sin )

diff

EARRA F

=

Where: = diffusion radiation factor.4 2 6 3 9 4

1(16.9 0.0001. 8.65.10 . 3.93.10 . 4.005.10 . )

d d d d n n n n

=+ + +

F= factor of view between the considered

surface and the sky:

1 cos

2F

+=

Inclined surface receives less diffuse radiation from atmosphere, but receive an additional

amount of reflected radiation due to the reflection from the ground. The Reflection factor iscalled albedo. It varies considerably depending on the nature of the soil, vegetation, etc. The

component reflected may be determined as:

0 .( sin ). .(1 )exp( / sin ) d

refl nEARRA C F

= +

Wheredn

= is the reflection factor of the surrounding ground (albedo).

The solar radiation incidence depends on two fundamental parameters: height of thesun and its

position.

Once solar elevation angle () and Azimuthal angle (Az) known then it is possible to calculate

instantaneous position of sun and incidence angle (between the normal to the surface and the

solar rays.) as shown in fig.4.

VI. SPECIFICATIONDC-motor specification

DC motors (instead of AC motors) because they could be directly coupled with PV arrays

and make a very simple system. Among different types of DC motors, a permanent

magnet DC (PMDC) motor is preferred in PV systems for tracking system because it can

provide higher starting torque, the DC voltage equation for the armature circuit is:

. .aV I R K = +

Where: Ra is the armature resistance. Increasing Ra The back emf is E=K where: K is the

constant, and is the angular speed of rotor in rad/sec.

We are using 2-POLE permanent magnet Lap wound dc motor. DGM-3440-12Volt, 286 rpm,4

Amp.


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Table 1: Specifications of Solar Photovoltaic Modules

VII. EXPERIMENTAL SETUPThe experiment has been performed at laboratory situated at Faculty of Engineering, DayalbaghEducational Institute, Agra. There are two solar panel systems viz. fixed and tracking system, onwhich for load four DC bulbs are directly connected ( two bulbs are in series) havingspecification each 90 Watts, 12Volt are connected to each system for experiment . Thespecification of each panel system is given below:

Fixed system: Having three panels each of 170 watts. Mounted on fixed mechanical structure

incline latitude at 29

0

south facing.

Tracking System: Number of panels in this system is also three, each of 170 watts. Mounted onrotating structure. It is rotating with the help of two 12Volt DC motors.

Both system panels are manufactured by BHEL. The same specifications are taken for bothsystems i.e. fixed and tracking system, to compare the performance of both systems. Thecomparison is carried out during different weather conditions and for different seasons. Thereadings are calibrated through digital voltmeters and analog ammeters.

VIII. REAL TIME DATA ANALYSIS OF CONTROL CIRCUITSince the whole system is to be implemented for real life application, for economicalpurpose we designed a very low cost Zig-bee based solar tracking system and analyzed theperformance of this during the sunny day.

IX. EXPERIMENTAL RESULTSThese data was taken in the month of September-20, 2012. Table.6 represents the fixed systemrecorded database and Table.7 represents recorded database for tracking system.

ConfigurationSingle Glass Laminated Type

With 72 Cells (12 6) In Series

Overall Size

1595 ( 3) 790 ( 2) 50 (

1) MMWeight 15 Kg. (Typical)

Module Frame Anodized Aluminum

Typical Electrical Characteristics of L24150 typemodule (170Wp)

Open Circuit Voltage (Voc)Short Circuit Current (Isc)Operating VoltageMax Power Output

42.0 V4.86 A35 V

170.0 W3%


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Table 2: Fixed system

Hour Voltage(V)

Current(Amp) Power(watt)

7.00am 0.816 1 0.816

7.30am 1.180 2 2.36

7.45am 1.168 2.5 2.92

8.00am 2.200 3 6.6

8.15am 3.485 4 13.94

8.30am 4.750 5.5 26.125

8.40am 7.35 6.5 47.775

8.55am 9.18 7.0 64.26

9.05am 10.41 7.52 78.2832

9.20am 12.51 8.40 105.084

9.36am 14.48 9.10 131.768

9.50am 16.21 9.6 155.616

10.05am 18.35 10.4 190.84

10.20am 19.28 10.6 204.368

10.40am 21.70 11.4 247.3810.54am 22.45 11.6 260.42

11.10am 23.22 11.9 276.318

11.25am 23.45 12.0 281.4

11.45am 23.87 12.0 286.44

12.00am 23.86 12.0 286.32

12.15am 23.91 12.1 289.311

12.40pm 23.04 12.1 278.784

1.00pm 23.91 12.1 289.311

1.10pm 23.90 12.1 289.19

1:25pm 23.81 12.0 285.72

1:44pm 22.90 12.0 274.8

1:55pm 22.83 11.9 271.677

2.10pm 21.51 11.7 251.6672.25pm 20.70 11.5 238.05

2.35pm 21.22 11.4 241.908

2.50pm 18.70 10.9 203.83

3.00pm 17.90 10.5 187.95

3.05pm 15.65 10 156.5

3.21pm 14.98 9.6 143.808

3.44pm 10.22 7.5 76.65

4.00pm 9.70 7.5 72.75

4.22pm 6.90 6.5 44.85

4.35pm 5.64 6.1 34.404

4.40pm 5.05 6 30.3


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Table 3: Tracking system

Hour Voltage (V) Current(Amp) Power(watt)

7.00am 0.941 0.2 0.1882

7.30am 1.350 1 1.35

7.45am 2.040 1 2.04

8.00am 1.189 1 1.189

8.15am 1.010 2 2.02

8.30am 6.60 3 19.8

8.40am 14.50 10.5 152.25

8.55am 16.02 11 176.22

9.05am 16.82 11.40 191.748

9.20am 17.87 11.70 209.079

9.36am 18.95 12.0 227.4

9.50am 19.80 12.40 245.52

10.05am 19.93 12.50 249.125

10.20am 20.12 12.50 251.5

10.40am 20.80 12.60 262.0810.54am 21.02 12.60 264.852

11.10am 21.04 12.75 268.26

11.25am 20.85 12.90 268.965

11.45am 20.69 12.75 263.7975

12.00am 20.23 12.50 252.875

12.15am 19.53 12.50 244.125

12.40pm 20.34 12.45 253.233

1.00pm 20.35 12.40 252.216

1.10pm 20.45 12.50 255.625

1.25pm 20.71 12.50 258.875

1.44pm 20.37 12.60 256.662

1.55pm 20.03 12.60 252.378

2.10pm 19.87 12.50 248.3752.25pm 17.85 12.00 214.2

2.35pm 19.04 12.10 230.384

2.50pm 17.26 11.80 203.668

3.00pm 17.06 11.50 196.19

3.05pm 14.66 11.00 161.26

3.21pm 14.16 10.90 154.344

3.44pm 10.07 9.00 90.63

4.00pm 10.38 9.00 93.42

4.22pm 7.93 8 63.44

4.35pm 6.62 7.5 49.65

4.40pm 5.26 7 36.82


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Figure 1 Graphical Representation of Power

Figure 2 Graphical Representation of Current

X. CONCLUSIONWe are getting total power from a tracking system 6825.754 Watts and from a fixed system

6330.493 Watts. Here we can conclude that with the help of tracking system we can extract

495.302 watts more power than a fixed system .From above calculated data dual axis tracking

system increases the efficiency of the system by 7.82%.

7 8 9 10 11 12 13 14 15 16 170

50

100

150

200

250

300

Time (24- hours)

Powerin

watts

power representation (Fixed s ystem)

power representation (Tracking sys tem)

7 8 9 10 11 12 13 14 15 16 170

2

4

6

8

10

12

14

Time(24-hours)

Current(Am

p)

Current (Fixed System)

Current (TrackingSy stem)


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REFERENCES

[1] E.C. Kern Jr, E.M. Gulachenski, G. A. Kern, Cloud effects on distributed photovoltaicgeneration slow transient at the gardner, Massachusetts photovoltaic experiment, IEEETransactions On Energy Conversion, Vol. 4, No. 2, June 1989.

[2] J.H.R. Enslin, M.S.Wolf, D.B. Snyman and W. Swiegers, Integrated photovoltaicmaximum power point tracking converter, IEEE Transaction On Industrial Electronics, Vol.44, No. 6, December 1997.

[3][3] R. Mukaro, X.F. Carelse, A microcontroller-based data acquisition system for solarradiation and environmental monitoring, IEEE Transaction On Instrumentation AndMeasurement, Vol. 48, No. 6, December 1999.

[4]E. Koutroulis, K. Kalaitzakis, N. C. Voulgaris, Development of a microcontroller-based,photovoltaic maximum power point tracking control system, IEEE Transactions On PowerElectronics, Vol. 16, No. 1, January 2001.

[5]Hession, P.J. and W.J. Bonwick, Experience with a Sun Tracker System, Solar Energy,Vol. 32, No. 1, pp. 3-11 (1984).

[6] Ayala, J. Kenneth, The 8051 Microcontroller Architec-ture, Programming and Applications,2nd Ed., Penram International Publishing Private Limited, India (1996).

[7]Kupta, K.C.,P.K.Mirakhur, and A.P.Sathe,A Simple solar Tracking System, SUN Proc. Int.Solar Energy Soc. ,New Delhi , India.

[8]B. S. William, G. Michael, Power from the Sun, June , 2006.[9]Zogbi, R. and B. Laplaze, Design and construction of sun tracker, Solar energy, Vol.33,

pp. 369-372. (1984)[10] Kupta, K.C.,P.K.Mirakhur, and A.P.Sathe,A Simple solar Tracking System, SUN Proc.

Int. Solar Energy Soc. ,New Delhi , India.K.S. Karimov, J.A. Chattha, M.M. Ahmed et al., Journal of References, Academy ofSciences of Tajikistan, Vol. XLV, No.9, 2002; pp. 75-83.

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Design, Development and Hardware Realization of X-beebased Single Axis Solar Tracking System