dual axis tracking systems
TRANSCRIPT
Dual Axis Tracking Systems
Dual axis tracking is typically used to
orient a mirror and redirect sunlight
along a fixed axis towards a stationary
receiver. But the system can also gain
additional yield on your PV cells. .
In the solar cell market efficiency is crucial to avoid losing market
shares on the global energy marketplace. There are two main ways
to make solar cells more efficient, either by improving the actual cell
or by installing the solar panels on a tracking base that follows the
sun.
The end-user will prefer a tracking solution rather than a fixed ground
system because:
• The efficiency increases by 20-60% (= more money) depending
on where you are in the world.
• Near the equator, you will have the highest benefit of tracking
the sun.
• The space requirement for a solar park is reduced, and they
maintain the same output
• The payback time of the investment is reduced
In this project we use one solar cell with two motor driver circuit to rotate
the solar cell in either direction for better efficiency. We use one solar cell ,
which is mounted on the wooden platform with 2 Dc motor on either side.
We use total 5 light sensor’s with microcontroller to interface to check the
maximum light intensity and rotate one motor for maximum intensity level.
5th sensor is mounted on the solar cell. To check the exact position of
maximum light.
In this project we use 5 ldr with ADC circuit of microcontroller. Here we
use PIC 16 f 887 ic. PIC 16f887 is inbuilt with 10 bit ADC circuit, 8
channel. We use the internal ADC of the microcontroller and get the data
from LDR. We use four sensor’s across the basic platform. Minimum two
sensor is always effected by the solar light and artificial light. When circuit
is on then controller get the data from LDR and compare the level of each
sensor’s. Microcontroller check the maximum level of light and command is
given to the microcontroller to rotate the motor. Motor maximum movement
is restricted by the Reed switch. Here we use four reed switch. One magnet
is pasted on the back side of the solar cell and when solar cell rotate then
solar cell magnet effect the reed switch . As the sensor is activate then sensor
provide signal to the microcontroller to stop the motor.
Pin no 11 and 32 is connected to the positive supply. Pin no 12 and 31 is connected to the ground pin. . Light sensor’s are connected to the pin no 2,3,4,7 of the port A of the PIC microcontroller. Pin no 2 is AN0, pin no 3 is AN1 , pin no 4 is AN2 and pin no 7 is AN4 of the controller..
Pin no 19,20,21 and 22 is connected to the motor driver circuit. Here we use 60 rpm dc motor. Motor is not connected to the microcontroller directly. We use h bridge circuit to drive the DC motor. For H bridge circuit we use four transistor base circuit to interface with the microcontroller circuit.
H RIDGE LOGIC
We use slow speed gear motor in this project . Working voltage of these motor’s
are 9 volt to 12 volt dc. We use two power source in this project. One for the
motor’s and second for the controller circuit.
For controlling a dc motor we use H bridge circuit. I this project we use four
transistor circuit to control the movement of dc motor
Collector of both the transistor is connected to the positive supply 9
volt. This 9 volt supply is for the DC motor. If we use 12 volt motor
then we use 12 volt dc supply here. Emitter of both the transistor is
connected to the DC motor. Emitter of the PNP transistor is
connected to the emitter of NPN transistor. Collector of both the PNP
transistor is connected to the ground potential. Base point of both
transistor is join together. On this point we give a voltage.
if we give a positive voltage to the base of left junction and negative voltage
to the right junction then motor moves to one direction. Because due to
positive on base NPN is on and due to negative on base PNP is on. If left
side NPN is on and right side PNP is on then motor moves to the one
direction. If the voltage is reverse on the base point then motor’s moves to
the reverse direction.
motor move to the reverse direction because base voltage is change . Now
left NPN and right PNP is on and motor moves to the reverse direction.
Now when we attach the H bridge to the logical output of the micro-
controller. So to interface the micro-controller with this H bridge we must
connect a OPTO-COUPLER with the controller.
Opto-Coupler is a special optically isolated device to interface the input with
output using light. Opto-Coupler provide a electrical isolation between the
input and output circuit .
Opto-coupler provide a isolation between the two power supply.
Microcontroller power supply is 5 volt dc and motor supply is vary from
9volt to 12 volt dc. With the help of the microcontroller we provide a
optical isolation between two power supply
In opto-coupler there is one input and one output and there is no connection
between input and output. On input point there is one infra red l.e.d. cathode
point of the l.e.d is connected to the resistor R1 and further connected to the
microcontroller ports. In this project we use two dc motor, so we use two H
bridge circuit with the four opto-coupler.