Transcript design of mobile pv system for measuring and analysing

Prepared by: Hamzah Snouber
For:
Dr . I mad Breik
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This project describes a recent work developed to
create a mobile stand alone photovoltaic
generator that can be easily relocated in remote
areas to evaluate the feasibility of photovoltaic
energy applications.
A set of sensors were installed to monitor the
electric current and voltage of the energy
generated, the energy stored and the energy used
by the loads that may be connected to the system.
 Other
parameters like solar radiations
were installed and temperature sensor
.This was done while considering the
important role of temperature in the
photovoltaic module performance.
 Finally,
a
measurement
and
communication hardware was installed to
interface the system developed with a
conventional computer. using c charp
software.
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Design and build a stand alone photovoltaic
system containing all the components required
to produce electricity from solar radiation.
Develop a set of measuring and analyzing tools
in order to evaluate the operation of the stand
alone
system
including
the
related
environmental conditions.
Design and build a device, integrated to the
stand alone system, that allows it to be
transported to remote sites in order to evaluate
its performance in specific environmental
conditions.
 In
order to classify the parts of the energy
generation system, considering its main
functions, three main blocks were defined:
1.Photovoltaic generator.
2.Measurement system.
3.Monitoring software.
 The
photovoltaic generator is the heart of
the
generation system.
 This generation block is formed by three
main areas:
1.Photovoltaic array.
2.Storage system.
3.Power conditioning system.
Modules
number
2 (Model
SR90)
Module power
55W
Array voltage
12 V
Array power
110 w
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It is known that a stand alone photovoltaic
system needs a storage system to provide energy
for the cases of inappropriate weather
conditions, instantaneous overload conditions,
or demand for energy after sunset.
The selected storage system, in this case a bank
of batteries, was configured considering the
amount of energy that can be generated by the
photovoltaic
array
and
its
electrical
characteristics

The power generated by the photovoltaic array
needs to be controlled in order to protect the life
of the batteries and to provide adequate
electrical energy to the loads connected to the
system.
 Two
power conditioning devices were
specifically used in this case:
1. Charge controller: to avoid overcharges or deep
discharge cycles in the bank of batteries.
2. Inverter: to provide power to AC loads.

A flexible measurement system was designed
to monitor the main parameters produced by
the generation system and by the
environmental conditions. In this way, the
measurement system will be conformed by
temperature sensors, solar radiation sensors,
transducers of electrical parameters
The current and voltage sensor
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This small voltage and current sense PCB was
designed for use in the AttoPilot UAV autopilot
system. DC current is determined by measuring
Voltage drop across a pair of parallel 1 milliohm
shunt resistors (0.5milliohm together) then
converted to final analog voltage output by the
Texas. Instruments INA-169. Voltage sense is
accomplished by
Scaling to 3.3V ADC range by a precision resistor
divider. The current limit coincides with maximum
power rating of the shunt resistors, 2 Watts each
(4Watts total).
Why I use this sensor and what is
purpose
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to determine open circuit voltage and short circuit
current
to determine the relationship between voltage and solar
radiation
to charge the battery from the sun and notice the charge
voltage
to notice the voltage wanted to the load from pv or from
battery
to notice the current which the pv array produce and to
evaluate the power from pv which is v*I and from battery
which is v*i
to draw the iv characteristics
to draw the output power of pv verses time
identify the form factor and the max power point
Solar radiation
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Cm11 are used solar radiation (kipp and zenon)
and it will put in the horizontal surface in order to
evaluate the solar radiation
Solar radiation is very important in my project and
the standard solar radiation is 1000w\m2
Now what is the importance of solar radiation on
pv module
From our project we notice that if solar radiation
increased Isc of the pv module increase and voc
will be the same and the current will be saturated
above 1000w\m2 .
Temperature sensor
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Temperature plays an important role in
photovoltaic generation Thus, in order to study
the impact of temperature on photovoltaic
generation
We study the relationship between pv and
temperature and we notice that if the (T )is
increase the vo.c is decreased according to the
following equation :
Tcell=Tamb+.0256*G
LOSSE IN VOLTAGE DUE TO INCREASE
TEMPRESURE
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Vloss=-2mv\cell.1c
Vloss=-2*40*(Tc-Tstandard)
In that G=1043, T=28
Tcell=28+.0256*1043=54.7C
Vloss=2m*40*(54.7-25)=2.37v
Vo.c =43.4+2.37=45.77v
The data logger
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micro controller which I use in my project is
pic16f877A
The PIC microcontroller is programmed to
control the physiological data collection. All
of these operations require controlled
timing which was achieved by the use of
timers.
WHY I SELECT PIC16F877A
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LOW OPERATING VOLTAGE _ The PIC16LF877A has a
wide operating voltage range from 2.0 V to 5.5V. This
feature makes it compatible with a low voltage source.
8-BIT ANALOG TO DIGITAL CONVERTER_ the
analog to digital converter in the PIC16LF877A can be set
to either an 8 bit or a 10 bit ADC.
TIMERS_ the PIC16LF877A provide 3 timers.
3-ADC channels_ for continuous monitoring of
temperature, current and voltage, the microcontroller has
to be equipped with at least three ADC channels. The
PIC16LF877A has 8 ADC channels.
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A software application was developed in the c
charp
programming
environment
to
communicate with the ‘‘pic-c’’ measurement
modules by means of a RS232 serial port.
 The main purpose of the software was to
monitor, to store and to visualize the
measured parameters from the stand alone
photovoltaic
system
and
from
the
environmental parameters related to the
photovoltaic generation.
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Screens of the software developed were
classified in the following types considering
their main function:
1.Presentation screen.
2.Measurement status screen.
3.Global and specific real time measurement
screens.
4.Visualization screen of stored data
This is some of data I will take it from my project:
time
1:10
1:11
G
800
800
T
33.2
33.2
Vpv
37.4
37
Ipv
0.4
0.44
power
1:12
1:13
1:14
1:15
1:16
1:17
1:18
1:19
800
800
800
800
800
800
800
800
33.2
33.2
33.2
33.2
33.2
33.2
33.2
33.2
36.6
36.2
35.8
35
34
33
0
38.7
.48
0.52
0.56
0.7
0.8
0.9
3.1
0
17.5
14.48
16.68
18.8
20
24.5
27.2
29.7
0
0
Time
12:00
12:01
12:02
12:03
12:04
12:05
12:06
12:07
12:08
12:09
G
980
980
980
980
980
980
980
980
980
980
T
28
28
28
28
28
28
28
28
28
28
Vpv
28.5
29.1
31
32
33
34
35
36
37
39
Ipv
3.25
3.17
2.9
2.72
2.5
2.2
1.8
1.45
1
0
Ppv
92.3
92.2
90
87
82.5
74.8
63
52.2
37
0
Thank you