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.