I seek to research a simple, cost effectual and robust solution to seting solar panels utilizing detectors photo transducer, Analog to digital converter and microcontroller. The thought behind this proposal consists of two exposure transducers that collect light from two different places on the solar panel and converts this visible radiation to Analog electromotive force. An analog-to-digital converter converts this electromotive force to digital format which can be fed to a Microprocessor. The microprocessor can take inputs from two detectors and make up one’s mind if we are roll uping maximal visible radiation of if we need to alter place.
There are two really clear advantages to this solution. One is: since this solution is closed loop i.e. take light input as a variable, accommodations are made till optimum point is reached. Besides, we can plan that accommodation to be made merely 3 or 4 clip a twenty-four hours non to do failure of mechanical parts. Second advantage is that all the portion of this system are off the shelf electronic constituents that brings down cost of execution for mass production.
Micro accountant is at the bosom of the system and following description gives an thought of this important component.The IC 8051 is a low-power ; high-performance CMOS 8-bit personal computer with 4K bytes of brassy memory. The device is manufactured by Atmel and is compatible with comparable industry pin out. There is advantage of brassy memory because it is non-volatile. This allows a plan to be stored even when we lose power. Atmel IC 8051 combines a 8-bit CPU with Flash memory on a individual dice bit. It besides provides a highly-flexible and cost-efficient solution to many embedded control applications.
Criterion features that semen with IC are: 4K bytes of Flash, 128 bytes of RAM, 32 I/O lines, two 16-bit timers and counters, a five vector double degree interrupt architecture, full semidetached house consecutive port and oscillator along with clock circuitry. In add-on to all this characteristics mentioned, ATMEL 8051 is designed with inactive logic for operation down to zero frequence and it supports two package selectable power salvaging manners. The Idle Mode stops the CPU while leting the memory, timer counters, consecutive port and interrupt system to go on operation.
Figure No. 1.1: Pin Diagram of 8051
The above block diagram explains internal circuitry of Microcontroller. These inside informations are needed to understand and plan microcontroller utilizing embedded programming methods.
ULN 2003 7805:
The ULN2001, ULN2002, ULN2003 and ULN2004 are high electromotive force, high current Darlington Arrays each contain seven unfastened aggregator Darlington pairs with common emitters. Each Channel rated at 500mA and can defy peak currents of 600mA. Suppression rectifying tubes are Included for inductive burden drive and the inputs are pinned opposite the end products to simplify board
Figure No. 1.4: ULN 2003
WHY WE USE ULN 2003?
Digital system and microcontroller pins lack sufficient current to drive the relay. While the stepper motor ‘s spiral needs around 10ma to be energized, the microcontroller ‘s pin can supply a upper limit of 1-2 ma current. For this ground, we place a driver.
The 555 massive timing circuit is a extremely stable accountant capable of bring forthing accurate clip holds, or oscillation. In the clip hold manner of operation, the clip is exactly controlled by one external resistance and capacitance. For a stable operation as an oscillator, the free running frequence and the responsibility rhythm are both accurately controlled with two external resistances and one capacitance. The circuit may be triggered and reset on falling wave forms, and the end product construction can beginning or drop up to 200 mas.
555 As Schmidt Trigger:
The buffer circuit ‘s input has a really high electric resistance ( about 1M ) so it requires merely a few µA, but the end product can drop or beginning up to 200mA. This enables a high electric resistance signal beginning ( such as an LDR ) to exchange a low electric resistance end product transducer ( such as a lamp ) .
It is an inverting buffer or NOT gate because the end product logic province ( low/high ) is the opposite of the input province:
Input low ( & A ; lt ; 1/3 Vs ) makes end product high, +Vs
Input high ( & A ; gt ; 2/3 Vs ) makes end product low, 0V
When the input electromotive force is between 1/3 and 2/3 Vs the end product remains in its present province. This intermediate input part is a dead infinite where there is no response, a belongings called hysteresis, it is similar recoil in a mechanical linkage. This type of circuit is called a Schmitt trigger.
If high sensitiveness is required the hysteresis is a job, but in many circuits it is a helpful belongings. It gives the input a high unsusceptibility to resound because once the circuit end product has switched high or low the input must alter back by at least 1/3 Vs to do the end product exchange back.
Stepper motor: There are several types of hoofer motors, these can non be driven in the same manner. In this application note, we have chosen to drive a unipolar hoofer motor For more information you will happen strategies to place the other types of hoofer motors.
Unipolar Stepper Motor unipolar hoofer motors are characterized by their center-tapped twists.
Unipolar Stepper Motor
Bipolar Stepper Motor Bipolar hoofer motors are designed with separate spirals.
Bipolar Stepper Motor
Variable Reluctance Variable reluctance hoofer motor ( besides called intercrossed motors ) are characterised by one common lead.
Variable Reluctance Stepper Motor
Driving unipolar Stepper Motors: There are three ways to drive unipolar hoofer motors ( one stage on, two stage on or half measure ) , each one has some advantages and disadvantages.
There are two phases to screening out which wire is which in a 5- or 6-wire unipolar hoofer motor:
Isolate the Common Power wire ( s ) by utilizing an ohmmeter to look into the oppositions between braces of wires. The Common Power wire will be the 1 with merely half as much opposition between it and all the others. This is because the Common Power wire merely has one spiral between it and each other wire, whereas each of the other wires have two spirals between them. Hence half the opposition.
Identify the wires to the spirals by providing a electromotive force on the Common Power wire ( s ) and maintaining one of the other wires grounded while anchoring each of the staying three wires in bend and detecting the consequences. Select one wire and land it Assume it ‘s connected to gyrate 4. Keeping it grounded, land each of the other three wires one by one Anchoring one wire should do the rotor turn a small clockwise. That ‘ll be the wire connected to Coil 3. Anchoring one wire should do the rotor turn a small anticlockwise. That ‘ll be the wire connected to Coil 1. Anchoring one wire should make nil that ‘ll be the wire connected to Coil 2.
Light Dependent Register: LDRs or Light Dependent Resistors are really utile particularly in light/dark detector circuits. Normally the opposition of an LDR is really high, sometimes every bit high as 1000 000 ohms, but when they are illuminated with light opposition beads dramatically.
Power supply: The power supply supplies power to the circuit at changeless electromotive force while pulling any sum of current. A unit which supplies the electrical energy to the burden is a power supply unit.
In our undertaking we need a 5V DC supply for all the constituents. The chief constituents in power supply unit are:
The constituents are briefly described below
Transformer: A device which transfers electrical energy from one circuit to another circuit is a transformer. This is done by inductive yoke. Transformer consists of primary twist, secondary twist and nucleus. Transformer follows the rule of common initiation.
A changing current in primary twist creates a variable magnetic field in the nucleus of the transformer. This changing magnetic field induces a changing electromotive force ( EMF ) secondary twist. This consequence is called common initiation.
Here we use a measure down transformer. A transformer can be made stepped down by doing primary bend ‘s more than secondary bends.
Rectifier: A rectifier is a device which converts jumping current to direct current. Here we use four rectifying tubes in signifier of a span which rectifies the current. Here we use a span rectifier.
In the below diagrams, when the input connected to the left corner of the square is positive and the right corner is negative, current flows from the upper supply terminus to take down supply terminal via the negative way.
Dc filter: When a span rectifier is used we require an extra capacitance. For this we use a DC filter to acquire uninterrupted end product with fixed mutual opposition. The capacitance filter is the most cardinal type of power supply filter. The usage of the simple capacitance filter is really limited and it is used on highly high-potential, low-current power supplies for cathode-ray and similar negatron tubings, which require really small load current from the supply. Here we use a full moving ridge capacitive filter.
The capacitance filter is used where the power-supply rippling factor is non important ; this frequence can be comparatively high. To extinguish ripple action the charge clip must be little and the discharge clip must be long. The figure is as shown below:
Regulatory IC ( 78XX ) : It is a three pin IC used as a electromotive force regulator. It converts unregulated DC current into regulated DC current. There are two types of electromotive force regulators. They are fixed voltage regulators and Variable electromotive force regulators. Here we use a fixed electromotive force regulator which may be either positive or negative. Here we use a 78XX positive electromotive force regulator. The most normally used regulators are 7805 and 7812.
Light breathing rectifying tube:
LED falls within the household of P-N junction devices. The light breathing rectifying tube ( LED ) is a rectifying tube that will give off seeable visible radiation when it is energized. In any forward biased P-N junction there is, with in the construction and chiefly near to the junction, a recombination of hole and negatrons. This recombination requires that the energy possessed by the unbound free negatron be transferred to another province. The procedure of giving off light by using an electrical beginning is called electroluminescence.
LED is a constituent used for indicant. All the maps being carried out are displayed by led.The LED is diode which glows when the current is being flown through it in frontward bias status. The LEDs are available in the unit of ammunition shell and besides in the level shells. The positive leg is longer than negative leg.
Research design and processs
The aim of this undertaking is to command the place of a solar panel in conformity with the gesture of Sun and do certain that solar panel gaining controls maximal sum of solar energy possible.
Brief Methodology: The angle at which Sun ‘s beam ‘s autumn on the surface of the solar panel determined the sum of energy captured by the solar panel. As described in statement of intent we explore the ways to car adjust place of solar panel to capture maximal sunshine.
This undertaking is designed with solar panels, LDR ( Light dependent resistance ) detectors, 555 Timer, Microcontroller, Stepper Motor and its drive circuit. In this undertaking two LDRs are fixed on the solar panel at two distinguishable points. LDR varies the opposition depending upon the light autumn. Since two detectors are located at two different topographic points on the panel we get two distinguishable oppositions matching to the manner panel Idaho oriented. This opposition is converted into a electromotive force by giving a bias current to LDRs. The born-again electromotive force is given as input to analog to digital convertor ( ADC ) .
Inside Analog to Digital Converter the varied opposition is compared with a mention electromotive force and converted into a digital signal. Then the born-again digital signal is given as the input of the micro accountant. Micro accountant receives the two digital signals from the detector circuit and compares them. Unless the solar panel is in optimum place where we get maximal solar energy, the LDR signals are non equal. When there is a difference between LDR electromotive force degrees, the microcontroller plan drives the stepper motor towards optimum place or normal incidence of sunshine. This as a feedback system as explained above since this rectification mechanism keeps go oning until solar panels are in optimum place.
Description of steps employed
Renewable energy is quickly deriving importance as an energy resource as fossil fuel monetary values fluctuate and developed states seeks to derive energy independency. As planetary heating and sustainable development are the corner rock ‘s of tomorrow ‘s economic system importance of renewable energy can non be exaggerated. At the educational degree, it is hence critical for technology and engineering pupils to hold an apprehension and grasp of the engineerings associated with renewable energy in general.
One of the most popular renewable energy beginnings is solar energy. Many researches were conducted to develop some methods to increase the efficiency of Photo Voltaic systems ( solar panels ) . One such method is to use a solar panel tracking system. This undertaking deals with a micro- accountant based solar panel tracking system. Solar tracking enables more energy to be generated because the solar panel is ever able to keep a perpendicular profile to the Sun ‘s beams. Development of solar panel tracking systems has been ongoing for several old ages now. As the Sun moves across the sky during the twenty-four hours, it is advantageous to hold the solar panels track the location of the Sun, such that the panels are ever perpendicular to the solar energy radiated by the Sun. This will be given to maximise the sum of power absorbed by PV systems. It has been estimated that the usage of a trailing system, over a fixed system, can increase the power end product by 30 % – 60 % . The addition is important adequate to do tracking a feasible preposition despite of the sweetening in system cost. It is possible to aline the tracking heliostat normal to sun utilizing electronic control by a micro accountant.
Design demands are:
1 ) During the clip that the Sun is up, the system must follow the Sun ‘s place in the sky.
2 ) This must be done with an active control, timed motions are uneconomical. It should be wholly automatic and simple to run. The operator intervention should be minimum and restricted to merely when there is system malfunction.
Based on above description, the demands for the system design can be derived as follows:
We have foremost take the processing unit which is the bosom of the system. We can travel for a application Specific Integred Chip ( ASIC ) or a Micro accountant based system with embedded package. For a solution such as we are suggesting, micro accountant nucleus is the right pick for the undermentioned grounds:
Micro accountants have cardinal processing unit ( CPU ) and Arithmetic and Logic Unit ( ALU ) that let us execute complex computations without demand of or connexion to a separate computing machine.
Non volatile memory like brassy memory that let us hive away plan and non lose the informations even if we lose power to the system.
Handiness of embedded scheduling tools that make it easy to custom-make the system.
Micro accountants are really cost effectual for mass productions as these are generic faculties that are produced in volume for many applications runing from microwave ovens to dish washers.
Application Specific Integrated Circuits need a batch of upfront production cost in footings of design technology and production. Besides we can non alter the plan by altering embedded microcode.
A typical solar tracking system with microprocessor nucleus is shown in the conventional below.
Once we have decided on the cardinal nucleus, we should plan the electronic system around it. Primary concerns in implementing the system are:
All electronic constituents require a fixed and regulated power supply for them to work as specified.
If we have signaled that are connected to many constituents, we need to measure the thrust strength or the current that is supplied by the bit that outputs the signal. If we do non hold sufficient thrust strength end product from micro accountant, we need to utilize a bit called buffer integrated circuit to give sufficient current.
Choosing 555 timer:
Given that solar tracker system is a closed cringle system, we get a batch of flexibleness in footings of taking constituents. If we choose an ADC that has less truth and if gives a consequence that is somewhat different from the most accurate consequence, we can ever rectify this as we get feedback until the solar panel is in optimum place.
Since this is a research undertaking we can show that we can acquire off with really low truth convertors by utilizing a 1-bit ADC which is basically a digital inverter. This thought is implemented utilizing a 555 timer in a Schmidt trigger constellation. Schmidt trigger constellation is needed to eliminated any noise from LDRs.
Choosing a buffer for microcontroller end products:
As discussed above, microcontroller end products might non hold adequate thrust strength to supply necessitate current to stepper motor. Digital systems and microcontroller pins lack sufficient current to drive the relay. While the stepper motor ‘s spiral needs around 10ma to be energized, the microcontroller ‘s pin can supply a upper limit of 1-2mA current. For this ground, we place a buffer driver between microcontroller and relays.
Choosing a stepper motor:
Unipolar hoofer motors with centre tapped weaving are ideally suited for our application since we have a individual power supply that is needed to power both the hoofer motor and remainder of the electronics. Having a centre tapped stepper motor lets us use the low electromotive force most efficaciously since we are efficaciously duplicating the electromotive force in a centre tapped transformer.
Theoretically we have two picks to power the electronic system. We could utilize the DC power supplied by the solar panel to power all the electronics and the stepper motor or we can acquire power from AC brinies. Both instances need step down from a higher electromotive force to lower electromotive force.
We choose to acquire power from the brinies for several grounds:
It is easy to step down AC electromotive force utilizing a transformer.
AC power would be more dependable on a cloudy twenty-four hours.
Most of the solar panels are connected to grid anyhow, So, acquiring AC power for electronics does non set any excess demands on the system.