Solar Tracker using Arduino

PROJECT'S GOAL

The purpose of this solar tracker project is to keep the photovoltaic solar panel perpendicular to the sun all year round to make it more efficient. The dual-axis photovoltaic solar panel takes astronomical data as a reference and the tracking system has the ability to always point the solar panel towards the sun and can be installed in different regions with minor modifications. The vertical and horizontal movement of the panel is obtained by taking the altitude angle and the azimuth angle as reference. The fuzzy controller has been used to control the position of DC motors. The dual-axis solar tracking system's mathematical simulation control ensures point-to-point movement of DC motors while tracking the sun.

Solar Tracker is a device that follows the movement of the sun as it rotates from east to west every day. The main function of all tracking systems is to provide one or two degrees of freedom of movement. Trackers are used to keep solar collectors/solar panels oriented directly toward the sun as it moves across the sky each day. The use of solar trackers increases the amount of solar energy that is received by the solar energy collector and improves the energy output from the heat/electricity that is generated. Solar trackers can increase solar panel production by 20-30%, which improves solar panel project economics.

NEED FOR SOLAR TRACKER

The energy provided by the direct beam decreases with the cosine of the angle between the incoming light and the panel. Not the table. 2.1 shows the

Direct power lost (%) due to misalignment (angle L ).

Table: Direct power lost (%) due to misalignment (angle L )

The sun travels 360 degrees east-west per day, but from the perspective of any fixed location the visible portion is 180 degrees over a half-day period. Local horizon effects reduce this somewhat, making the effective movement about 150 degrees. A solar panel with a fixed orientation between the extremes of sunrise and sunset will see a 75 degree movement on both sides and therefore, according to the table above, will lose 75% of its power in the morning and evening. Rotating the panels east and west can help recover these losses. A tracker rotating in the east-west direction is known as a single-axis tracker.

The sun also moves 46 degrees north-south over the period of one year. The same set of panels placed at the midpoint between the two local extremes will see the Sun move 23 degrees on each side, causing losses of 8.3%. A tracker that accounts for daily and seasonal movements is known as a dual-axis tracker. Tracker Design

TRACKER DESIGN

A solar tracker is a device that orients the photovoltaic array towards the sun. In flat panel photovoltaic (PV) applications, trackers are used to minimize the angle of incidence between incoming light and a photovoltaic panel. This increases the amount of energy produced by the photovoltaic array.

Here we can use Altitude and Azimuth Dual Axis Trackers (AADAT). Dual-axis trackers extract maximum levels of solar energy due to their ability to follow the sun vertically and horizontally. No matter where the sun is in the sky, dual-axis trackers are able to position themselves in the direction of the sun.

A square solar panel configuration has two degrees of freedom. Here, two DC motors are used to drive the two rotational degrees of freedom. Motors can be mounted directly on the rotation pins of rotational joints to reduce losses caused by linkages and joints and avoid the use of more links and mechanisms

DC MOTOR AND DRIVER

Tracking systems would need to consist of two motors, which control the position of the array, and a control circuit (analog or digital) to drive these motors. The following sections discuss some possible types of engines that can be used for this type of application.

MATHEMATICAL MODEL

The fig. 3.3 shows typical behavior of the Sun's trajectory in December (winter) and June (summer). The angle of rotation of the guidance system in the vertical plane can be calculated from the following equation:

Fig. 3.3 Typical behavior of the Sun's trajectory in December (winter) and June (summer). _).

System design

SYSTEM DESIGN

The purpose of a solar tracker is to accurately determine the position of the sun. This allows the solar panels to interface with the tracker for maximum solar radiation. With this specific solar tracker a closed circuit system was made.

General system block diagram

The electrical system consists of five LDR sensors that provide feedback to a microcontroller. This microcontroller processes the sensor input and provides two PWM signals to move the servomotors.

This servo motor moves the solar panel toward the highest density of sunlight. The entire electrical system is powered by a 12 volt power supply.

Initially five different analog values ​​are obtained from the LDRs and then fed to the microcontroller. The microcontroller provides two different PWM signals for the movement of the solar panel through the servo motor.Sensors

SENSORS

We are using five light dependent resistors as sensor. They sense the area of ​​greatest density of sunlight. The solar panel moves to the high light density area through servo motors.

Each LDR is connected to the power supply forming a potential divider. Thus, any change in light density is proportional to the change in voltage across the LDRs.

LDR is a passive transducer, so we will use a potential divider circuit to obtain corresponding voltage value from the LDR resistance.

The resistance of LDRs is inversely proportional to the intensity of the light that falls on it, that is, the greater the intensity or brightness of the light, the lower the resistance and vice versa.

Interfaces:

Input (ADC):

The Arduino has a built-in 10-bit analog to digital converter (ADC), so it can provide digital values ​​from 0 to 1023 (since 2^10 = 1024). We can also set the ADC reference voltage on Arduino, but here we will let it use the default value. The LDR has two pins and to obtain the voltage value we use the potential divider circuit. turn is a function of the light falling on the LDR. The greater the light intensity, the lower the LDR resistance and, therefore, the lower the output voltage (Vout). The lower the light intensity, the greater the LDR resistance and, therefore, the greater the Vout.

Output (PWM):

Arduino has an 8-bit PWM generator, so we can get up to 256 PWM signal. To drive a servo we need to get a PWM signal from the board, this is usually done using the microcontroller's timer function, but Arduino makes this very easy. Arduino provides a servo library in which we have to assign only the servo angle (0-1800) and the servo rotates at that angle, all the PWM calculations are handled by the servo library and we get a clean PWM signal as per the desired angle.

ARDUINO SEVERINO BOARD:

PCB file

Final project