Solar Inverter Using Tracking System for Maximum Output

SOLAR INVERTER USING TRACKING SYSTEM Page 1
1.1 URGE FOR POWER IN INDIA
India currently suffers from a major shortage of electricity generation capacity, even though it
is the world's fourth largest energy consumer after United States, China and Russia.
In December 2011, over 300 million Indian citizens had no access to electricity. Over one
third of India's rural population lacked electricity, as did 6% of the urban population
Despite an ambitious rural electrification program, some 400 million Indians lose electricity
access during blackouts. While 80% of Indian villages have at least an electricity line, just
52.5% of rural households have access to electricity. In urban areas, the access to electricity
is 93.1% in 2008. The overall electrification rate in India is 64.5% while 35.5% of the
population still lives without access to electricity.
Over 2010–11, India's industrial demand accounted for 35% of electrical power requirement,
domestic household use accounted for 28%, agriculture 21%, commercial 9%, public lighting
and other miscellaneous applications accounted for the rest.
INTRODUCTION Chapter 1

1.2 SOLAR - AN IMMENSE SOURCE OF ENERGY
Rajasthan, Gujarat, west Madhya Pradesh and north Maharashtra receives more than 3000 to
3200 hours of bright sunshine in a year. Over 2600 to 2800 hours of bright sunshine are
available over the rest of the country.
As far as the availability of global solar radiation is concerned, more than 2000 kWh/m2-
year are received over Rajasthan and Gujarat, while east Bihar, North West Bengal and the
north-eastern states receive about 1700 kWh/m2-year.
There are about 300 clear sunny days in a year in most parts of India and the daily average
solar energy incident over India varies from 4-7 kWh/m2.
Solar energy technologies include solar heating, solar photovoltaic, solar thermal electricity
and solar architecture, which can make considerable contributions to solving some of the
most urgent problems the world now faces.

1.3 MOTIVATION
The sun emits lots of energy in the form of heat in 1 day. By using solar panel we can convert
this heat energy into electric energy. With the growing popularity of solar panel and there
evergreen use(along with the push to get more out of solar panel.) It was our desire to make a
sort of project which could help the world to produce green electricity. So we decided to
make a sort of inverter in which the load would be supplied power through the solar energy.
The electric energy produced through panel depends on the sun rays fall on the panel. If sun
rays fall exactly perpendicular to the panel then we get maximum output voltage. This is the
reason to track the sun.
Tracking forces the panel to face the sun for much longer period of time. With tracking
mechanism, the efficiency of panel will be about 40% higher than fixed type.
The electric energy produced through panel depends on the sun rays, strike on the panel. If
sunrays strike exactly perpendicular to the panel then we get max output voltage so that is the
reason to track the sun. This is our main goal of the project.
With the growing popularity of solar panels and their ever growing use(along with the push
to get more out of solar panels) it was our desired to experiment with tracking the sun from
dawn to dusk. This tracking forces the panel to face the sun for much longer periods of time.
The experiment carried out here is to help us examine the most amount of solar energy
received by the panel, with tracking the sun as against fixed position solar panel. With
tracking mechanism, the efficiency of panel will be about 40% higher than the fixed type.
The project requires general electrical and electronics knowledge with exposure of
microcontroller design and software.

2.1 BLOCK DIAGRAM
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FIG : 2.1.1 BLOCK DIAGRAM
SOLAR
PANEL
POWER
SUPPLY
ADC 8051 MICRO
CONTROLLER
BATTERY RELAY
PIC
CONTROLLER
RELAY
POWER
SUPPLY
MOSFET
RELAY
COM
COM
NO
NO
NC
NC
NC
NO
HARDWARE DESCRIPTION Chapter 2

2.1.1 DESCRIPTION
The basic block diagram is as shown in fig. no 2.1.1. Here the solar panel converts the solar
energy into the electricity . Now to have maximum conversion of the solar energy , the solar
panel is moved in the direction of sun , which is commonly known as the solar tracking
system.
The level of charging in the battery is checked by the micro-controller , and if the battery
voltage is higher than the set point it will charge the relays to normally close.
With the help of mosfet driver and the center tapped transformer , the DC voltage of the
battery is converted to the AC voltage and the bulb is switched off. Now if the battery voltage
in than the set point, the bulb is lit through the main power supply.

2.2 CHARGE CONTROLLER
The primary function of a charge controller in a stand-alone PV system is to maintain the
battery at highest possible state of charge while protecting it from overcharge by the array.
Although some PV systems can be effectively designed without the use of charge control,
any system that has unpredictable loads, user intervention, optimized or undersized battery
storage (to minimize initial cost) typically requires a battery charge controller. The algorithm
or control strategy of a battery charge controller determines the effectiveness of battery
charging and PV array utilization, and ultimately the ability of the system to meet the load
demands.
Additional features such as temperature compensation, alarms, meters, remote voltage sense
leads and special algorithms can enhance the ability of a charge controller to maintain the
health and extend the lifetime of a battery, as well as providing an indication of operational
status to the system caretaker.
Important functions of battery charge controllers and system controls are:
Prevent Battery Overcharge: to limit the energy supplied to the battery by the PV array when
the battery becomes fully charged.
Provide Load Control Functions: to automatically connect and disconnect an electrical load
at a specified time, for example operating a lighting load from sunset to sunrise.

2.2.1 OVERCHARGE PROTECTION
A remote stand-alone photovoltaic system with battery storage is designed so that it will meet
the system electrical load requirements under reasonably determined worst-case conditions,
usually for the month of the year with the lowest insolation to load ratio. When the array is
operating under good-to-excellent weather conditions (typically during summer), energy
generated by the array often exceeds the electrical load demand. To prevent battery damage
resulting from overcharge, a charge controller is used to protect
the battery. A charge controller should prevent overcharge of a battery regardless of the
system sizing/design and seasonal changes in the load profile, operating temperatures and
solar isolation.
Charge regulation is the primary function of a battery charge controller, and perhaps the
single most important issue related to battery performance and life. The purpose of a charge
controller is to supply power to the battery in a manner which fully recharges the battery
without overcharging. Without charge control, the current from the array will flow into a
battery proportional to the irradiance, whether the battery needs charging or not. If the battery
is fully charged, unregulated charging will cause the battery voltage to reach exceedingly
high levels, causing severe gassing, electrolyte loss, internal heating and accelerated grid
corrosion. In most cases if a battery is not protected from overcharge in PV system,
premature failure of the battery and loss of load are likely to occur.
Charge controllers prevent excessive battery overcharge by interrupting or limiting the
current flow from the array to the battery when the battery becomes fully charged. Charge
regulation is most often accomplished by limiting the battery voltage to a maximum value,
often referred to as the voltage regulation (VR) set point.
Sometimes, other methods such as integrating the ampere-hours into and out of the battery
are used. Depending on the regulation method, the current may be limited while maintaining
the regulation voltage, or remain disconnected until the battery voltage drops to the array
reconnect voltage (ARV) set point.

2.2.2 TERMINOLOGY & DEFINITIONS
Charge regulation is the primary function of a battery charge controller, and perhaps the
single most important issue related to battery performance and life. The purpose of a charge
controller is to supply power to the battery in a manner to fully recharge the battery without
overcharging. Regulation or limiting the PV array current to a battery in a PV system may be
accomplished by several methods. The most popular method is battery voltage sensing,
however other methods such as amp hour integration are also employed. Generally, voltage
regulation is accomplished by limiting the PV array current at a predefined charge regulation
voltage. Depending on the regulation algorithm, the current may be limited while
maintaining the regulation voltage, or remain disconnected until the battery voltage drops to
the array reconnect set point.
While the specific regulation method or algorithm vary among charge controllers, all have
basic parameters and characteristics. Charge controller manufacturer's data generally provides
the limits of controller application such as PV and load currents, operating temperatures,
parasitic losses, set points, and set point hysteresis values. In some cases the set points may
be dependent upon the temperature of the battery and/or controller, and the magnitude of the
battery current.

2.2.3 CHARGE CONTROLLER CIRCUIT
FIG: 2.2.1 CHARGE CONTROLLER CIRCUIT

2.2.4 DESCRIPTION
First of all solar battery gets charged with the help of solar panel. the voltage obtained from
the solar panel is first compared with the specific set voltage with the help of operational
amplifier LM358. this is because, when the voltage of the panel is less than that of the solar
panel, reverse current would flow, as a result of which the solar panel might get damaged.
now as per the voltage of the solar panel and the already specified set voltage on the
operational amplifier, the charging condition is displayed on the LCD display with the help of
8051 microcontroller.
Now the present voltage of the battery is read through the ADC, which will convert the
analog value to the digital value. this value is buffered on the 8051 micro controller which is
then displayed on the LCD screen.
The present value of the battery voltage is compared with the already specified set voltage.
this set point can be changed with the help of the two switches given in the circuit. According
to the output of the comarision, the pin 3.2 of the microcontroller will give the output.if the
battery voltage is higher than the set point, it will turn on the transistor by giving supply to
the gate of the transistor BC547. this transistor is used as a pull-up transistor and this will
accordingly make the relay to normally close. the NO end of the relay is inturn connected
with the battery. and the bulb will be lit with the help of the battery.

2.2.5 COMPONENTS OF CHARGE CONTROLLER
16X2 LCD DISPLAY(CFA635)
FIG: 2.2.2 LCD DISPLAY
GENERAL DESCRIPTION
LCD (Liquid Crystal Display) screen is an electronic display module and find a wide range of
applications. A 16X2 LCD display is very basic module and is very commonly used in
various devices and circuits. These modules are preferred over seven segments and other
multi segment LEDs. The reasons being: LCDs are economical; easily programmable; have
no limitation of displaying special and even along with custom characters (unlike in seven
segments)animations.
In a 16X2 LCD, it can display 16 characters per line and there are 2 such lines. In this LCD
each character is displayed in 5X7 pixel matrix.This LCD has two registers, namely,
Command and Data. The command register stores the command instructions given to the
LCD. A command is an instruction given to LCD to do a predefined task like initializing it,
clearing its screen, setting the cursor position, controlling display etc. The data register stores
the data to be displayed on the LCD. The data is the ASCII value of the character to be
displayed on the LCD. Click to learn more about internal structure of a LCD.

FEATURES
 5X8 and 5X10 dot matrix possible.
 Low power operation support.
 Wide range of liquid crystal driver power.
 Liquid crystal drive waveform.
 Correspond to high speed MPU bus interface.
 4-bit or 8-bit MPU interface enabled.
 80X8 bit diaplays RAM.
 9,920 bit character generator ROM for a total of 240 character fonts.
 64X8 bit character generator RAM.
 Programmable duty cycles.
 Wide range of instruction function:
 Display clear, cursor home,display on/off,cursor on/off,displaycharacter blink,cursor
shift,display shift.
 Pin function compatibility with HD44780S.
 Automatic reset circuit that initializes the controller/driver after power on.
 Internal oscillator with external resistors.
 Low power cosumption.

 ADC0804
FIG:2.2.3 ADC 0804
FEATURES:
 80C48 and 80C80/85 Bus Compatible - No Interfacing Logic Required
 Conversion Time <100µs
 Easy Interface to Most Microprocessors
 Will Operate in a “Stand Alone” Mode
 Differential Analog Voltage Inputs
 Works with Bandgap Voltage References
 TTL Compatible Inputs and Outputs
 On-Chip Clock Generator
 Analog Voltage Input Range (Single + 5V Supply)
 No Zero-Adjust Required
 80C48 and 80C80/85 Bus Compatible - No Interfacing Logic Required
KEY SPECIFICATIONS
 Resolution: 8 Bits
 Total error: ±1/4 LSB, ±1/2 LSB and ±1 LSB
 Conversion Time: 100 μs

TYPICAL APPLICATION SCHEMATIC
FIG:2.2.4 APPLICATION SCHEMATIC OF ADC0804

 BC547
FIG: 2.2.5 BC547 NPN TRANSISTOR
FEATURES
 Low current (max. 100 mA)
 Low voltage (max. 65 V).
APPLICATIONS
 General purpose switching and amplification.
DESCRIPTION
 NPN transistor in a TO-92; SOT54 plastic package.
 PNP complements: BC556 and BC557.

 8051 CONTROLLER
FEATURES
The Intel 8051 is Harvard architecture, single chip microcontroller (µC) which was
developed by Intel in 1980 for use in embedded systems. 8051 is an 8-bit micro controller.
The Important features of 8085 Architecture:
 8-bit ALU, Accumulator and Registers
 8-bit data bus - It can access 8 bits of data in one operation
 16-bit address bus - It can access 216 memory locations - 64 kB ( 65536 locations ) each
of RAM and ROM
 On-chip RAM - 128 bytes ("Data Memory")
 On-chip ROM - 4 kB ("Program Memory")
 Four byte bi-directional input/output port
 UART (serial port)
 Two 16-bit Counter/timers
 Two-level interrupt priority
 Power saving mode
 The Intel 8051 is used in embedded systems
 8-bit CPU
 4 k bytes ROM for the program
 128BYTESof RAM forvariables
 32I/Olines(4PORTSWITH8EACH)
 2 timers
 1 Serial port
 6Interrupt sources
 Low cost 10-15 cents per

2.3 INVERTER
A power inverter, or inverter, is an electrical power converter that changes direct current
(DC) to alternating current (AC),the converted AC can be at any required voltage and
frequency with the use of appropriate transformers, switching, and control circuits.
Solid-state inverters have no moving parts and are used in a wide range of applications, from
small switching power supplies in computers, to large electric utility high-voltage direct
current applications that transport bulk power. Inverters are commonly used to supply AC
power from DC sources such as solar panels or batteries.
The inverter performs the opposite function of a rectifier. The electrical inverter is a high-
power electronic oscillator. It is so named because early mechanical AC to DC converters
were made to work in reverse, and thus were "inverted", to convert DC to AC.

2.3.1 INVERTER CIRCUIT
FIG : 2.3.1 CIRCUIT OF INVERTER

2.3.2 WORKING
Inverter is used to generate Alternating Voltage/Current from Direct Voltage/Current.
In the Inverter circuit we have used PIC16F887 microcontroller for driving the MOSFETs
IRF54N.Here we have also used MCT2E optoisolator for isolation between the MOSFETs
and PIC controller. This avoids the danger of damaging the microcontroller. Alternately the
MOSFETs are turned ON and OFF to get an alternating signal. A center tapped transformer is
used for amplifying the signal.
The PIC controller works on 12 MHz crystal frequency. It also required 5V DC for working.
The controller produces two 100 Hz frequency pulses which are fed in the MOSFETs. Here
pin 19 and 20 which are for RD0 and RD1 are used.This produces a resultant output
alternating signal of 50 Hz from the MOSFETs.
MCT2E optoisolator is of 5 pins. Input from the PIC controller is applied to pin 1 and output
is given from pin 5 respectively for the two signals. Pin number 2 and 4 are applied to
ground.
The signal is then passed through the center tapped transformer which has 12V DC voltage
reference and other two inputs are from the MOSFETs.
Center Tapped transformer is step up, thus amplifying the signal and giving us the final
output of 230 V 50 Hz.

2.3.3 COMPONENTS
 MOSFET IRF540N
FIG: 2.3.2 MOSFET IRF540N
FEATURES:
 Advanced Process Technology
 Ultra Low On-Resistance
 Dynamic dv/dt Rating
 175°C Operating Temperature
 Fast Switching
 Fully Avalanche Rated
 MCT2E OPTOCOUPLER
FIG 2.3.3 MCT2E OPTOCOUPLER

FEATURES:
 Interfaces with common logic families
 Input-output coupling capacitance < 0.5 pF
 Industry Standard Dual-in line 6-pin package
 5300 VRMS isolation test voltage
APPLICATION:
 AC mains detection
 Reed relay driving
 Switch mode power supply feedback
 Logic ground isolation
 Logic coupling with high frequency noise rejection

 PIC CONTROLLER:
FIG: 2.3.4 PIC CONTROLLER PIN DIAGRAM

Microcontroller Core Features:
 High performance RISC CPU
 Only 35 single word instructions to learn
 All single cycle instructions except for program branches which are two cycle
 Operating speed: DC - 20 MHz clock input DC - 200 ns instruction cycle
 Up to 8K x 14 words of FLASH Program Memory,Up to 368 x 8 bytes of Data Memory
(RAM) Up to 256 x 8 bytes of EEPROM Data Memory
 Pinout compatible to the PIC16C73B/74B/76/77
 Interrupt capability (up to 14 sources)
 Eight level deep hardware stack
 Direct, indirect and relative addressing modes
 Watchdog Timer (WDT) with its own on-chip RC oscillator for reliable operation
 Programmable code protection
 Power saving SLEEP mode
 Selectable oscillator options
 Low power, high speed CMOS FLASH/EEPROM technology
 Fully static design
 In-Circuit Serial Programming(ICSP) via twopins
 Single 5V In-Circuit Serial Programming capability
 In-Circuit Debugging via two pins
 Processor read/write access to program memory
 Wide operating voltage range: 2.0V to 5.5V
 High Sink/Source Current: 25 mA

2.4 SOLAR TRACKING
The main aim of solar tracking is that one can achieve maximum output voltage across solar
panel. The condition for getting maximum output voltage is that the sun and the panel both
are exactly perpendicular to each other at particular time.
As the name implies a “SOLAR TRACKING” is an instrument used to track solar panel to
get maximum energy. In solar tracking, solar panel is remaining position in direction of solar
rays. We use LDR for detecting the maximum intensity of solar energy, this information is
provided to the microcontroller which rotates the motor accordingly. It should be noted here
that we are using a DC motor for movement of the panel.
When the sun is at the extreme west direction the panel accordingly rotates to the extreme
west direction. There is a limit switch which is placed. This switch detects the panels extreme
westward position and gives signal to the controller.
Controller thus rotates the motor in clockwise direction i.e west to east and then places the
panel in its initial position.

2.4.1 BLOCK DIAGRAM
FIG: 2.4.1 BLOCK DIAGRAM OF SOLAR TRACKING
2.4.2 DESCRIPTION:
Here microcontroller 8051 is main heart of our solar tracking system. External power supply
is applied to the controller as well as the DC motor.
With the help of the limit switch and the resistance of the LDR we can know the exact
position of the sun. The microcontroller will work accordingly and will stop the motor when
the position of the panel is exactly perpendicular to the sun rays because of this the maximum
solar energy is available for the recharging of the solar battery.
DC MOTOR
POWER
SUPPLY
LIMIT
SWITCH
8051 MICRO
CONTROLLER
LDR
BATTERY
SOLAR
PANEL

2.4.3 CIRCUIT DIAGRAM:
FIG 2.4.2 CIRCUIT DIAGRAM

2.4.4 DESCRIPTION
The microcontroller is central part of the tracking system through which the command will be
given to the parts. Main function is controlled by it only. We are using 8051 microcontroller.
The LDR gives right information about the exact position of the sun. Mainly 5V is given to
microcontroller and 12V is supplied to motor.with the help of DC motor the solar panel
moves in the direction of the Sun.Now during evening time,the panel comes in the west
direction it will press the west limit switch, and the solar panel now moves in the east most
direction.
In solar tracking system we are using LDR resistance .When sun light falls on LDR, LDR
resistance is decreases. So output of op-amp becomes high . Here two limit switch one for
east direction and another one for west direction are used. When port 3.0 of 8051 becomes
high output of 7 NPN array transistor high and relay get 12 volt ,DC motor rotate in clock
wise direction. On another hand when port 3.1 of 8051 becomes high according to limit
switch position relay get supply and DC motor rotate in anticlock wise direction.

2.4.5 COMPONENTS
 LDR
FIG:2.4.3 LDR
DESCRIPTION:
Two cadmium sulphide(cds) photoconductive cells with spectral responses
similar to that of the human eye. The cell resistance falls with increasing light
intensity. Applications include smoke detection, automatic lighting control,
batch counting and burglar alarm systems.
FEATURES:
 Quick Response
 Reliable Performance
 Epoxy or hermetical package
 Good Characteristic of Spectrum
APPLICATIONS:
 Photoswitch
 Photoelectric Control
 Auto Flash for Camera
 Electronic Toys, Industrial Control

 ULN2003-TRANSISTOR ARRAY:
FIG 2.4.4 ULN 2003
DESCRIPTION
The ULN2003 is a monolithic high voltage and high current Darlington transistor arrays. It
consists of seven NPN darlington pairs that features high-voltage outputs with common-
cathode clamp diode for switching inductive loads. The collector-current rating of a single
darlington pair is 500mA. The darlington pairs may be paralleled for higher current
capability.
APPLICATIONS
 Relay drivers
 Hammer drivers
 Lamp drivers
 Display drivers(LED gas
 discharge)
 Line drivers
 Logic buffers.
 The ULN2003 has a 2.7kW series base resistor for each
darlington pair for operation directly with TTL or 5V CMOS devices.

FEATURES
 500mA rated collector current(Single output)
 High-voltage outputs: 50V
 Inputs compatibale with various types of logic.
 LM7805:
FIG: 2.4.5 LM 7805
FEATURES:
 Output Current up to 1A
 Output Voltages of 5, 6, 8, 9, 10, 12, 15, 18, 24
 Thermal Overload Protection
 Short Circuit Protection
 Output Transistor Safe Operating Area Protection

 DC MOTOR:
FIG :2.4 .6 DC MOTOR
DC motor generates torque directly from the applied DC power. There are two types of DC
motor based on rotation:
 Unidirectional
 Bidirectional
Here, we are using bidirectional DC motor as we have to control gate operation in both
directions. Motor driver IC is required for controlling of motor. We are using motor
having 10 rpm.
Advantages :
 Low initial cost
 High reliability
 Simple control of motor speed

3.1 FLOW DIAGRAM OF CHARGE CONTROLLER
START
STOP
LCD
STARTUP
START
ADC
READ
ADC
CHECK SOLAR
PLATE POWER
CHECK CHARGING
CONDITION ON/OFF
RETURN
IF ADC>
SET
POINT
RELAY 1 OFFRELAY 1 ON
YES NO
SOFTWARE DESCRIPTION Chapter 3

3.1.1 DESCRIPTION
The main function of the 8051 microcontroller here is that to check the present voltage of the
battery and to compare it with the set value. Another function of the controller here is that it
will check if the battery is getting charged with the solar panel or not.
First of all, the 8051 microcontroller will initialize the LCD display and the ADC. then it will
check the value of the battery voltage and compare it with the set value. if the set value is
higher than the battery voltage the micro controller will switch off the relay. and if the battery
voltage is higher than the set point, the controller will make the relay on.
Than after this, the controller will check the charging condition of the solar panel and will
display accordingly on the LCD screen.

3.2 FLOW DIAGRAM OF INVERTER
START
STOP
PORT DO-ON
PORT D1-OFF
DELAY 10mS
PORT DO-OFF
PORT D1-ON
DELAY 10mS
RETURN

3.2.1 DESCRIPTION :
Our main aim is to generate 100Hz frequency which turns the MOSFETs ON and OFF
alternatively.
This is achieved by providing a 10ms delay between the signals.
Initially port D0 is is high whereas D1 is low, a 10 ms delay is applied. In the succeeding
section D1 is kept high whereas D0 is low. This procedure is followed continuously.
Output what we get from the MOSFETs is a 50Hz frequency signal.
This signal is passed through a centre tapped transformer which is step up. A 12 V DC is
applied as reference voltage to this transformer. The signal is amplified and we get 230 V AC
output.

3.3 FLOW DIAGRAM OF SOLAR TRACKING
START
CHECK EAST SWITCH
MOTOR IS OFF
STOP MOTOR
ROTATE WEST
CHECK
WEST SW
RETURN
STOP
CHECK
SENSOR
WAIT
SENSOR
IF PRESS
YES
YES
NO
NO
YES
NO
NO
YES

3.3.1 DESCRIPTION
In solar tracking first of all initialize the position of the DC motor and the solar panel.in the
initial condition DC motor is off and the solar panel is fixed. Now the controller checks for
the condition of the limit switch, if the east limit switch is pressed then the motor is off and it
again checks the position of the sensor. Then sensor starts to sense the position of the sun
light, when the maximum sun light falls on the LDR resistance, the solar panel stop to rotate
at that particular point. now the LDR continuously sense the maximum sun light. as soon as
the sun light reduces LDR will sense the reduction in the energy and it will again rotate the
panel with the help of the DC motor and stops at the point of the maximum sun light. At the
evening time, the solar panel will be in the west direction. now when the west limit switch is
pressed, the DC motor will start moving in the opposite direction and will bring the solar
panel in the east direction again.

Solar Inverter Using Tracking System for Maximum Output

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