Saturday, July 11, 2009



1.1 Definition of Inverter with Solar Battery Charger:
Inverter is an electronic device which is DC to AC converter. It simply converts direct current to alternating current. Its name also indicates that it has exactly opposite operation to that of a rectifier. A rectifier converts AC to DC. The process through which inverters convert DC to AC supply is called “inversion”, so it named as an inverter.
Inverter mainly consists of two circuits as charging circuit, inverting circuit, and a battery. The battery used is a normal lead-acid battery which can either be charged by ac mains supply or by using the solar battery charging kit as shown below :

Figure.1.1 Basic Block Diagram
The charger circuit keeps the battery charged when either of the power supplies is available and when the supply fails, the inverter circuit takes the DC power stored in the battery and converts it into 230v/50Hz AC supply, which can be used to power any common electrical/electronic equipment.

1.2 Basic Principle of Inverter:
Inverter is a device which converts the DC supply to AC supply. Let us see how it generates AC supply from DC supply.

Figure 1.2. Basic Principle of Inverter
In this circuit DC input from battery is given to an inverter ckt and then its ac output to a transformer. When the switch is closed the current starts to rise in the ckt. This will make the transformer to generate an EMF, opposing the EMF of the battery. If we assume that the resistance of the transformer is negligible, then the current will rise at a constant rate. This rise will depend on the inductance of the transformer; the more time will be needed, to produce the required current to balance the EMF of the battery.
Now if switch is opened before the current in the transformer grows fully, the current in circuit will start to fall. This will make the transformer to generate reverse EMF. Now, once the ckt current reaches zero, the switch is once again closed and this whole process will start to repeat itself. So, by producing open, close cycle of switch in this circuit, we can produce ac current o/p from a dc current source i.e. battery. The o/p from secondary winding of transformer will be a square wave of frequency at which switch is opened and closed; this is the basic working principle of inverter.

1.3 Classification of Inverter:
Inverter can be classified on the basis of nature of source, nature of output waveform, type of commutation circuit used, configuration and type of power semiconductor devices used. 1. Based on nature of input source:
a) Voltage source inverter: In this input to the inverter is DC voltage.
b) Current source inverters: In this voltage is converted into current source and then applied to inverter as i/p.
2. Based on type of commutation ckt used:
a) Auxiliary
b) Complementary.
3. Based on power semiconductor devices used:
a) Thyristorized
b) Transistorized
c) MOSFET based
d) IGBT based
4. Based on configuration of inverter:
a) Series
b) Parallel
c) Bridge
5. Based on nature of output waveform:
a) Square
b) Quasi-Square
c) PWM wave.
d) Sine wave.


2.1 Relevance:
The greatest need of today’s world is energy, which may be in any form. But the form of energy that is required the most is the electrical energy. The electrical energy is non-renewable source of energy, so the need of the hour is to find out the ways to utilize the available electrical energy carefully and to optimally use the renewable resources of energy which are present in abundance in the environment. The inverter is an electronic device, which provides the electrical energy that is stored in a battery. Today inverter is an essential commodity to provide an uninterrupted power supply for the houses, offices, schools, hospitals etc. With our project we are trying to interface the inverter with user and sun so that the user can make an optimum use of solar energy. We will do this by making the inverter programmable for the user so that he can get his required performance from the inverter and by attaching a battery with solar charger which in turn will save energy as well as money.

2.2 Present Theories:
The inverter is basically a DC to AC converter, which converts DC energy stored in battery in AC energy for everyday requirement and provides uninterrupted power supply. The inverters available in the market are of different range, specifications and cost. The inverters are available in different output waveforms which are,
1) Square wave inverters.
2) Quasi-square wave inverters.
3) PWM inverters.
4) Sine wave inverters.
There are inverters available which control the output voltage by the use of PWM pulse, these inverters use IC 3525 to produce PWM wave. These inverters uses the led’s to indicate ON/Off condition of inverter.
Hence, we can say, according to our survey we found that inverter is the most essential and important device in the field of electronics development. Keeping this in mind we are making an inverter which not only provides a continuous power supply but also saves the tremendous of non-renewable resources of energy by using solar energy.
2.3 Proposed Work:
Inverters which are available in the market are just passive product i.e. you have to use them only in one way. The concept of our project is to make these widely used devices active and user friendly by making them flexible in their use. We can program the inverter as we like with the help of microcontroller used in it. The microcontroller is also used to produce PWM wave instead of using IC 3525. Also we are charging the battery by means of the solar energy which not only saves the money but also saves the tremendous of non-renewable resources of energy i.e. electrical energy.
The programmable inverter is unique in following ways,
1) Programmable output wattage and display.
2) Programmable charging current and display.
3) User interface using remote control.
4) LCD display.
5) Battery state display.
6) Backup time display.
7) Extendable output wattage by the use of dual battery.
8) Input voltage and frequency display.
9) Required text display.
10) Battery charging takes place by means of solar energy.


3.1 Block Diagram of Programmable Inverter:
Figure3.1: -Block Diagram of Programmable Inverter

3.2 Block Diagram of Solar Battery Charger:

Figure 3.2:- Block Diagram of Solar Battery Charger

1. Microcontroller 89C52: -
The AT89C52 is a low-power, high-performance CMOS 8-bit microcontroller with 8K bytes of in-system programmable Flash memory. The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry standard 80C51 instruction set and pin out.
Memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with in-system programmable Flash on a monolithic chip, the Atmel AT89S52 is a powerful microcontroller which provides a Highly-flexible and cost-effective solution too many embedded control applications.
The AT89C52 provides the following standard features: 8K bytes of Flash, 256 bytes of RAM, 32 I/O lines, Watchdog timer, two data pointers, three 16-bit timer/counters, a six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator and clock circuitry. In addition, the AT89S52 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes.
The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port, and Interrupt system to continue functioning. The Power-down mode saves the RAM contents but freezes the oscillator, disabling all other chip functions until the next interrupt or hardware reset.

Features of this microcontroller are :
· Compatible with MCS-51® Products
· 8K Bytes of In-System Programmable (ISP) Flash Memory
· 4.0V to 5.5V Operating Range
· Fully Static Operation: 0 Hz to 33 MHz
· Low-power Idle and Power-down Modes
· 256 x 8-bit Internal RAM
· 32 Programmable I/O Lines
· Three 16-bit Timer/Counters

Microcontroller is used as the controlling device of the system. It is connected with the LCD Display, Remote, Pre amplifier, EEPROM, Triac and Triac driver circuits, Multiplexer, changeover relay. Microcontroller will generate the PWM pulse with 50 Hz frequency. O/P of microcontroller is given to the pre amplifier.

2. PIC16F877A 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
• Power-on Reset (POR)
• Power-up Timer (PWRT) and Oscillator Start-up Timer (OST)
• 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 two pins
• 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
• Commercial and Industrial temperature ranges
• Low-power consumption:
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Peripheral Features:

• Timer0: 8-bit timer/counter with 8-bit prescaler

• Timer1: 16-bit timer/counter with prescaler, can be incremented during sleep via external crystal/clock

• Timer2: 8-bit timer/counter with 8-bit period register, prescaler and postscaler

• Two Capture, Compare, PWM modules

- Capture is 16-bit, max. resolution is 12.5 ns

- Compare is 16-bit, max. resolution is 200 ns

- PWM max. resolution is 10-bit

• 10-bit multi-channel Analog-to-Digital converter

• Synchronous Serial Port (SSP) with SPI (Master Mode) and I2C (Master/Slave)

• Universal Synchronous Asynchronous Receiver Transmitter (USART/SCI) with 9-bit address detection.

• Parallel Slave Port (PSP) 8-bits wide, with external RD, WR and CS controls (40/44-pin only)

• Brown-out detection circuitry for Brown-out Reset (BOR)

3. Pre Amplifier: -

1. It is designed by using the transistors

2. We will use transistor BC 547 for designing the pre amplifier.

3. Pre amplifier is used to amplify o/p, which is present at the micro controller o/p terminals.

4. By using the pre amplifier we are converting the 5v s/g to 12v which is required to drive the power MOSFETs.

5. The pre-Amplifier converts the microamperes current from m/c to ma.

4. Power Amplifier :-

1. Power amplifier is designed by using the power MOSFETs.

2. The MOSFET’s used are IRF3205 and are connected in push pull configuration.

3. Power amplifiers are used to improve the power handling capability of ckt.

4. Power Amplifiers will convert the current in ma to the current in several amperes.

5. Voltage Booster:-

1. Voltage booster is consisting of the transformer it will act as step up or step down on the basis of the operation mode of inverter.

2. At the o/p of step up transformer we get the 230v ac o/p.

3. Voltage booster will get the i/p from the power amplifiers.

Transformer: -

A transformer is a device which works on principle of mutual induction.

Transformers are available in two types step up transformer and step down transformer.

Step up transformer is used to increase the secondary (output) voltage in proportion to primary (input) voltage.

Step down transformer is used to decrease the secondary (output) voltage in proportion to primary (input) voltage.

The transformer is rated in volt-amperes rather than in watts.

Advantages of transformer : -

1. The output can be varied proportional to the input.

2. Noiseless transfer of power from primary to secondary, as there is no mechanical parts involved.

3. As there is no electrical contact between the primary and secondary of the transformer, circuit connected to the secondary is safe from the electric shock

Parts of a transformer

Coil: - In a transformer, coil is one of the most important part and we require wire to make the coil.

Former/bobbin: - In the transformer the coil is wrapped around a former or a bobbin.

Bobbin is made o some insulated material such as plastic, paper, fiber etc. in power transformers the bobbin is usually made of plastic or fiber, this keeps the bobbin safe from the heat/cold and humidity.

Core: - Core is the heart of transformer. If a solid iron piece having low resistance is used as core, then too much of eddy current will flow in the core and make it very hot.

To increase the resistance of core, instead of using a single solid iron piece, thin laminated iron sheets are joined together to form the core. This increases the resistance and narrows sown the eddy current path. Which in turn improves the productivity if the transformer a makes it less hot. The core is available in various sizes and numbers. Other than E&I shape of English letter U&T is also very common for the core.


The EEPROM are fabricated using MOS technology only i.e. only using MOSFETs.

1) In this, memory data can be written any number of times.

2) Chip can be erased by exposing it to UV rays called EPROM OR it can be electrically erased referred as EEPROM.

3) This is used when one wants to developed digital computer system.

4) Technique used for erasing is exposure to ultraviolet light.

5) Selective erasing is not possible. All the locations get erased.

6) Time required for erasing is long 10 to 15 min.

7) It is necessary to remove the PROM.

8) EPROM is less expensive.

9) It is an UV erasable & electrically programmable EPROM, a transparent lid is provided in the package.

7. Relay:-

An electromagnetic relay is basically a s/w operated by magnetic force. This magnetic force is generated by flow of current through a coil in a relay .The relay opens or closes a ckt when current through a coil is started or stopped. The Relay which we have used is OEN-58-06-2C.

8. TRIAC And TRIAC Driver :-

We are using the BT139 as Triac and MOC 3021 as a Triac driver. Triac is basically used to control the charging current by controlling the 230V AC voltage by controlling the phase angle of triac. We control the 230V AC supply by giving appropriate gate pulses to it. When the mains AC supply fails the m/c detects it and start controlling the gate pulses given to triac using triac driver. It is the 6 pin IC.

It is used as the TRIAC driver.

9. LCD Display:-

The LCD is used to display the information or user’s database, entering amount. The LCD panel's Enable and Register Select is connected to the Control Port. The Control Port is an open collector / open drain output. While most Parallel Ports have internal pull-up resistors, there are a few which don't. Therefore by incorporating the two 10K external pull up resistors, the circuit is more portable for a wider range of computers, some of which may have no internal pull up resistors. We make no effort to place the Data bus into reverse direction. Therefore we hard wire the R/W line of the LCD panel, into write mode. This will cause no bus conflicts on the data lines. As a result we cannot read back the LCD's internal Busy Flag which tells us if the LCD has accepted and finished processing the last instruction. This problem is overcome by inserting known delays into our program. The 10k Potentiometer controls the contrast of the LCD panel. Nothing fancy here. As with all the examples, I've left the power supply out. You can use a bench power supply set to 5v or use a onboard +5 regulator. Remember a few de-coupling capacitors, especially if you have trouble with the circuit working properly.

· LCD Module : In recent years the LCD is finding widespread use replacing LEDs (Seven Segment LEDs or other multistage LEDs). This is due to the following reasons: The declining prices of LCDs. The ability to display numbers, characters and graphics. This is in contrast to LEDs, which are limited to numbers and a few characters. Incorporation of a refreshing controller into the LCD, thereby relieving the CPU of the task of refreshing the LCD. In contrast, the LED must be refreshed by the CPU (or in some other way) to keep displaying the data.

The constructional diagram of LCD Module is as shown

Figure : Constructional Diagram of LCD Module

Reflective twisted pneumatic liquid crystal display.
1.Vertical filter film to polarize the light as it enters.
2.Glass substrate with ITO electrodes. The shapes of these electrodes will determine the dark shapes that will appear when the LCD is turned on or off. Vertical ridges etched on the surface are smooth.
3.Twisted pneumatic liquid crystals.
4.Glass substrate with common electrode film (ITO) with horizontal ridges to line up with the horizontal filter.
5.Reflective surface to send light back to viewer. (In a backlit LCD, this layer is replaced with a light source.)

When VCC and VSS provide +5V and ground respectively, VEE is used for controlling LCD contrast.
RS (Register Select):
There are two very important registers inside the LCD. The RS pin is used for their selection as follows. If RS = 0, the instruction command code register is selected, allowing the user to send a command such as clear display, cursor at home, etc. If RS = 1 the data register is selected, allowing the user to send data to be displayed on the LCD.
R/W (Read/Write):
R/W input allows the user to write information to the LCD or read information from it. R/W = 1 when reading, R/W = 0 when writing.
E (Enable):
The enable pin is used by the LCD to latch information presented to its data pins. When data is supplied to data pins, a high – to – low pulse must be applied to this in order for the LCD to latch in the data present at the data pins. This pulse must be a minimum of 450 ns wide.
D0 – D7:
The 8-bit data pins, D0 – D7 are used to send information to the LCD or read the contents of the LCD’s internal registers.
To display letters and numbers. We send ASCII codes for the letters A – Z, a – z and numbers 0 – 9 to these pins while making RS = 1.
There are also instruction command codes that can be sent to the LCD to clear the display or force the cursor to the home position or blink the cursor. Table below lists the instruction command codes.


4.1 Circuit Diagram of Inverter:

4.2 Circuit Diagram of Solar charging kit:

4.3 Circuit Diagram Description:

As seen from the circuit diagram different resistors, capacitors, inductors IC’s . We have used the microcontroller IC89s52,multiplexer CD4051,EEPROM24c02, PC817,Triac Driver MOC3021,Triac BT139,Transformer,Regulator IC 7805, 7812,op-amp LM324 ,LM393 ,transistors Bc547,Bc557, diodes 1N4148,1N4007,BA159
Pin no. 1 of micro controller is connected to the preamplifier circuitry .the preamplifier circuitry is three stage amplifier. The amplifier is connected in CE configuration. We have use the BC547 for designing the preamplifier.
Pin no.3 is also connected to the second preamplifier circuitry which is also design by using BC547 the output of these two preamplifier circuitry are connected to power amplifier stage. This stage is design by power MOSFET we have used IRF3205 for designing the power amplifier this power amplifier is designed in push-pull configuration the out of these push-pull amplifier stage is given to 12-0-12 winding of transformer. The two diode(1N4007) at the power amplifier stage are used to avoid damaged due to reverse voltage of 12V.
Pin no.4 ,5 & 6 of microcontroller is connected to the EEPROM IC24C04 which is 8 terminal IC. Microcontroller will read this memory at time each run. This memory will store the values which are changed by the user.
Pin no 7 & 8 are open.

Pin no-9 is reset pin of microcontroller and it is connected to the reset circuit.
Pin no-10 is connected to the buzzer circuit, which consists of transistor & buzzer, which will work when mains supply is absent.
Pin no-11 is connected to the relay circuit it consists of transistor BC547,relay switch used is 58-06-2C. two diodes at this stage are used to avoid the relay chattring.this relay circuit is of two stage.

Pin no-12 is connected to interrupt circuit which is designed by using BC547.

Pin no-13 is connected to remote sensor
Pin no-15 is connected to third driver circuit this third circuit comes into action when there is inductive load it consist of transistor which is connected in common emitter configuration output of this stage is given to two power MOSFET IRFP250 through 470 ohm resistances .output of these MOSFET is given to 50V winding of transformer.
Pin no-16 of micro controller is connected to MOC3021 output of 3021 is connected to Triac circuitry. Triac is used to control charging current. Pin no-17 is given to PC817 which is used for fuse blow indication
Pin no-18 &19 are XTAL1 &XTAL2 of microcontroller these pins are connected to oscillator circuit .this oscillator circuit will generate the clock to synchronize all the internal operation of microcontroller. We have used 24MHz crystal oscillator capacitors c1 &c2 are used to stabilize the n/w
Pin no-21 –27are connected to LCD display Pin no-21-D4,22-D5,23-D6,24-D7,25-enable,26-RS and 27-switch..

Pin no-22-24 are also connected to Pin no-9,10,11 of CD4051 which will act as multiplexer lines of CD4051. CD4051 has diff. Input from main supply voltage ,inverter voltage through bridge rectifier and op-amp circuit . we have used LM324 for our purpose CD4051 is also connected with inverter current circuit and charging current circuit also battery voltage is given to CD4051 input terminal .

Pin no-3 is output pin of CD4051 which is connected to microcontroller Pin no-28 through op-amp.

Pin no-29-36 are open,pin-no28,37,38 are connected to no-40 is Vcc of microcotroller.

It is a 150w, 10-0-10 V transformer. The transformer is working as step down in charging mode and step up in the inverter mode. In charging mode the transformer not only steps down the voltage to safe value but also isolates the low power electronic circuitry from high power mains and it also charges the battery in this mode. During step up operation it is provided with the pulses from the microcontroller.

There are various types of voltage regulator but we choose 7805 regulators due to their simplicity.
These are the reasons why regulators are used (why simple power supply does not provide constant output voltage):-
· Output voltage varies with ac input.
· Output voltage changes with functions in dc load current.
· Output voltage varies with time temperature particularly if semiconductor devices are used.
Three terminal voltage regulator in which the fixed output voltage is available at one pin without any connection. Only 3 terminals are required for such device i.e. input (Vm), output (Vo) and ground.
78XX series consists of 3 terminal positive voltage regulators and is available in seven fixed voltage regulators 7805 series provides out =put current in excess of 500 mA with adequate heat sink.
These IC’s also have internal short circuit protection and thermal shutdown circuit.
Other Components:-
Resistors should read their correct value, but again, in-circuit tests can be misleading. All diodes should show proper conduction and blocking as the probes are switched from one end to another. This is not a useful for LEDs or zener diodes, but at least u will know if it is open or short circuit.
Capacitors really need a capacitance meter (as well as an ESR [Equivalent series resistance]) to test properly, but u can still get a fair idea with a multimeter. Shorts r uncommon in films caps, but can occur, although in most projects this is unlikely. Electrolysis should show a low resistance a first, which rise as the capacitor charges.
Reverse the leads and make sure that the cap discharges (except to see silly resistance values at first) and charges up again. Low voltage reverse polarity will not harm electros. Most other components need only to be checked for continuity, and that all wiring is connected to the proper place.

Schematic/PCB Errors:-
There are few (if any) schematic errors on the PCB/ESP. This is not always the case however, and there are many errors to be found in schematics on the Web and even established and normally reliable magazines can (and do) make mistakes. Sometimes these mistakes will prevent circuit from working at all, so be warned.
While there may be occasional PCB error in some of the projects PCBs, the error is clearly explained in the construction notes , and will usually only be a minor-major mistakes require the artwork to be re-done (which is expensive) , but no ESP circuit. Board requires any modification track errors are fixed, regardless of the cost.

Incorrect Components:-
All components must ne inserted in the correct place, as shown on the PCB overlay and/or other instructions. While this may seen obvious, it is the most common form of “component failure” the component is not faulty per se, but if it is in the wrong place it will affect the operation of the circuit. This is made worse by the fact that many components use “strange”’ the component is
With resistors, unless u knows the colour code very well, it is good idea to measure all the colour coded resistors before insertion. This is especially true with 1% 4-band codes, as they can be very confusing even for professionals! There is some information about basic components, markings etc in the article section of this site. This is not comprehensive and cannot be there are just too many different devices available to cover them all.
Always make sure that download the manufacturers data sheet for transistors, ICs etc. It isn’t uncommon that suppliers will substitute brand names parts with “equivalents” these may be as good as the original but they may also have different pinots. The only way to know for sure is to get the data sheet from the company who actually made the device u have applies mainly to semiconductor , but also may be concern for relays, some electrolytic capacitors (especially power supply filter caps), and other components as well. For semiconductors most will be fine, but expensive power output transistors are regularly counterfeit! Occasionally, u will get a brand new, brand name component that is faulty .Irrigating? Of course it is, but also inevitable this where you really do need to hone your fault finding skills, since it is clearly not the result of a mistake on your part. These faults can be difficult to find, and require a disciplined approach to troubleshooting to repair.

# Calculation for battery backup time for given load:-

For 100W output load and 70Ah battery,
Power = Voltage X Current
100 =230 X I

Thus, I = 0.434A

Also, battery capacity (C)= Constant discharge X Time duration beyond which
current (I) the battery voltage falls below final discharge voltage ( t)

But, C = 70Ah

Thus, 70Ah = 0.434 X t
Hence, t = 161hr.


In this Inverter, charging current, o/p wattage, is controlled or changed according to user requirement within the battery limit by using the microcontroller. Microcontroller has I/p as inverter vtg, mains vtg, charging c/n, inverter c/n through the op-amp. M/C is connected with LCD display, EEPROM, relay, remote, Triac and Triac driver ckt, pre amplifier, mux.
Inverter can basically operate in three different modes as:-
A) Inverter Mode:-
In the inverter mode of operation inverter can operate as follows,
Mux has different i/p from the inverter o/p, battery vtg, mains vtg., charging c/n, inverter c/n it is given to the mux through the op-amp 741. M/C will select the i/p depending on its requirements. M/c will generate a 50 Hz PWM pulse which is given to pre-amplifier where it is get amplified then its o/p is given to power amplifier. O/p of power amplifier is given to voltage booster, which is basically a step up transformer. O/p of step up transformer is ac o/p 230V.EEPROM stores the parameters of inverter which are entered by user according to his requirement. When AC mains supply fails then relay switches to battery and Inverter will operate in Inverter mode & when it is connected to mains vtg it is in charging mode and battery is in charging condition. We can change the charging C/N, o/p wattage, o/p voltage as per the requirement & this can be achieved by using remote control that is connected to micro controller. So, we can say our Inverter is programmable Inverter. LCD display is used which displays charging C/N, O/P voltage, back up voltage battery voltage.

B) Charging Mode:-

System Operates in Charging Mode when either the AC mains supply or the solar energy or both are available.
When mains is available:
1. The M/c detects that AC mains supply is available and it gives the signals to triac driver which controls the gate pulses given to triac. Due to the gate pulses the Output vtg of triac is controlled which in turn controls the charging current given to the battery. The o/p of triac is connected to the transformer which is operated as step-down transformer and it gives 12V and required charging current at the secondary which charges to battery.
When the solar energy is available:
2. The panel o/p is given to the battery with a diode connected in between the positive terminals of the panel and the battery. Because of this the feedback from battery to the solar charging kit will not be there as the diode will be in reverse biased mode.

C) Programming Mode:-

In this Mode the System is programmed according to the users requirement with the help of IR Remote.
In this mode we can program
1) Output voltage.
2) Output Current.
3) Charging Current.
4) Text Display.

The values of above Parameters given by user are stored in EEPROM. When microcontroller wants this value then it will read this from the EEPROM.

5.1 Battery Charging in Inverter:
In an inverter when the mains ac available the mains supply is connected to 0-230v taping of inverter transformer through a relay .In this situation transformer works as a step down transformer, which has 0-140v taping at the primary and 12-0-12v at secondary. This voltage at secondary is used to charge the battery connected to the inverter when the mains ac supply fails the relay makes 12-0-12v taping primary and 0-230v taping secondary this makes the inverter to provide 230v ac supply from the 12v battery so when single transformer is used for inverter and charger operation then the transformer is act as step up transformer and step down transformer for inverter and charging mode resp..
One of the most part of inverter is battery. It is the source of power when mains supply fails. Proper working of inverter dependence on conditions and capabilities of battery being used.
There are two categories of battery:
a) Primary Battery:-
Primary batteries are for single use as the chemical reaction that produces electric current in them are irreversible these are chip and simple to use.
E.g. Zinc carbon battery, zinc manganese alkaline battery.
b) Secondary Battery:-
Secondary battery are rechargeable battery the can use multiple times. These batteries can be use in industries and automobiles where higher initial current is required.
E.g. nickel cadmium, lead acid battery
Backup time provided by inverter mainly depends on rating of battery use with them. Voltage rating and ampere hr rating is used to define power availability or capacity of battery .The backup time provided by battery connected to inverter depends on the dc bus voltage of inverter. Life of battery is depend on charging method use to charge the battery Three types of charging circuits are used in inverter to charge the battery, Constant voltage, constant current, constant voltage constant current.

Storing Solar Energy in Batteries:

The most common method of storing solar electricity is to use it to charge batteries. Building a solar-powered battery charger is an inherently safe activity because of the way solar cells self-limit the amount of current they produce. Recharging a battery at too fast a rate (too high a current) might cause a buildup of gas inside the battery, potentially causing it to explode. Charging batteries with mini–solar panels eliminates this potential safety hazard. The voltage of a power source indicates its ability to force electrons through an electrical circuit. When a battery is connected to a circuit, it forces electrons out of its negative terminal (marked with a minus [-] sign), through the circuit, and into its positive terminal (marked with a plus [+] sign). This action slowly changes the chemical makeup of the battery.
With use, this change reduces the voltage of the battery and at some point the battery can no longer force the electrons through the circuit. At this point we say the battery is “dead.”
For some dead batteries, another power source can be used to force the electrons to flow in the opposite direction and cause the chemical makeup of the battery to return to its original state. The battery is then “recharged.” In order to do this, the voltage of the other power source must be greater than the charged voltage of the battery.

Lead-Acid Battery Operation:-
Lead-Acid Battery Charging :
Lead-acid battery chargers attempt to force constant voltage
– Bulk charge - At max. current, battery voltage is below set point
_ Battery voltage increases as the battery charges
– Once the battery recovers sufficient charge, voltage is controlled
_ May be 2 stage charge - bulk & constant voltage (14.0V)
_ May be 3 stage charge - bulk, acceptance (14.3V) & float (13.3V)
_ May offer equalization (15.3V) mode for periodic battery conditioning

Solar Panel:
Determine your solar charging goals and estimated power use
– Continuous dry camping
_ Refill at least what you use each day
_ Can require a large solar system, perhaps 150 - 300W or more
– Long weekend dry camping
_ Refill a portion of what you use each day
_ If you can last 3 days on 200 amp-hours, one 75W panel can extend this to ≈ 5 days, or two 75W panels to ≈ 12 days
– Storage maintenance
_ 50W is usually sufficient

Solar Charging System :
A solar charging system consists of one or more solar panels and a charge controller.
– Charge controller prevents overcharging the battery
– May display battery voltage and/or charge current

The Photo Voltaic Module Charger Controller:
There are three types available
1. On/Off (bang-bang) type controller
_ Disconnects module when high battery voltage is reached (≈ 14V)
_ Reconnects module when battery voltage lowers (≈ 13V)
_ Control may be relay or solid state
2. Pulse Width Modulation (PWM)
_ When desired battery voltage is reached (≈ 14V) output turns on/off
quite rapidly (100Hz - 50KHz)
_ Battery voltage held constant, producing a more fully charged battery
3. Maximum Power Point Tracking (MPPT)
_ Provides PWM type battery voltage control
_ Extracts all available power from the PV module
_ Patent Pending Solar Boost TM MPPT technology can increases charge
current up to 30% or more compared to traditional charge controllers

Photovoltaic Electricity :
Photovoltaic (PV) is the field of technology and research related to the application of solar cells for energy by converting sunlight directly into electricity. Due to the growing need for solar energy, the manufacture of solar cells and photovoltaic arrays has expanded dramatically in recent years
The bottom layer is doped with a P type material such as Aluminum, Gallium or Indium to produce holes (the green circles). The N type layer is doped with Phosphorous, Arsenic or Antimony to create mobile electrons (the blue dots). The figure has two phases. The dark phase in which no light is necessary and the light phase in which light is necessary.
DARK PHASE: Initially no charge difference exists between the barrier junction. However because of the crystalline nature of Silicon electrons unbounded by a stable octet in the N layer have a tendency to migrate across the junction barrier to form a stable octet in the P layer. When this happens a difference in potential is set up between the two layers.
LIGHT PHASE: Electrons become excited when light quanta penetrates into the P layer. The excited electrons have two choices of movement. They may migrate through the external circuit or short circuit there way across the barrier junction. If the photoelectric circuit is constructed correctly they will find their way back to the N junction through the external circuit.

Photo generation of charge carriers:
When a photon hits a piece of silicon, one of three things can happen:
1. The photon can pass straight through the silicon — this (generally) happens for lower energy photons,
2. The photon can reflect off the surface,
3. The photon can be absorbed by the silicon, if the photon energy is higher than the silicon band gap value. This generates an electron-hole pair and sometimes heat, depending on the band structure.

When a photon is absorbed, its energy is given to an electron in the crystal lattice. Usually this electron is in the valence band, and is tightly bound in covalent bonds between neighboring atoms, and hence unable to move far. The energy given to it by the photon "excites" it into the conduction band, where it is free to move around within the semiconductor.
The covalent bond that the electron was previously a part of now has one fewer electron — this is known as a hole. The presence of a missing covalent bond allows the bonded electrons of neighboring atoms to move into the "hole," leaving another hole behind, and in this way a hole can move through the lattice. Thus, it can be said that photons absorbed in the semiconductor create mobile electron-hole pairs.
A photon need only have greater energy than that of the band gap in order to excite an electron from the valence band into the conduction band. However, the solar frequency spectrum approximates a black body spectrum at ~6000 K, and as such, much of the solar radiation reaching the Earth is composed of photons with energies greater than the band gap of silicon. These higher energy photons will be absorbed by the solar cell, but the difference in energy between these photons and the silicon band gap is converted into heat (via lattice vibrations — called phonons) rather than into usable electrical energy.

Charge carrier separation
There are two main modes for charge carrier separation in a solar cell:
1. Drift of carriers, driven by an electrostatic field established across the device
2. Diffusion of carriers from zones of high carrier concentration to zones of low carrier concentration (following a gradient of electrochemical potential).
In the widely used p-n junction solar cells, the dominant mode of charge carrier separation is by drift. However, in non-p-n-junction solar cells (typical of the third generation of solar cell research such as dye and polymer thin-film solar cells), a general electrostatic field has been confirmed to be absent, and the dominant mode of separation is via charge carrier diffusion.

The p-n junction (Semiconductor):
The most commonly known solar cell is configured as a large-area p-n junction made from silicon. As a simplification, one can imagine bringing a layer of n-type silicon into direct contact with a layer of p-type silicon. In practice, p-n junctions of silicon solar cells are not made in this way, but rather, by diffusing an n-type dopant into one side of a p-type wafer (or vice versa).If a piece of p-type silicon is placed in intimate contact with a piece of n-type silicon, then a diffusion of electrons occurs from the region of high electron concentration (the n-type side of the junction) into the region of low electron concentration (p-type side of the junction). When the electrons diffuse across the p-n junction, they recombine with holes on the p-type side. The diffusion of carriers does not happen indefinitely however, because of an electric field which is created by the imbalance of charge immediately on either side of the junction which this diffusion creates. The electric field established across the p-n junction creates a diode that promotes current to flow in only one direction across the junction. Electrons may pass from the n-type side into the p-type side, and holes may pass from the p-type side to the n-type side, but not the other way around.
This region where electrons have diffused across the junction is called the depletion region because it no longer contains any mobile charge carriers. It is also known as the "space charge region".

Connection to an external load:
Ohmic metal-semiconductor contacts are made to both the n-type and p-type sides of the solar cell, and the electrodes connected to an external load. Electrons that are created on the n-type side, or have been "collected" by the junction and swept onto the n-type side, may travel through the wire, power the load, and continue through the wire until they reach the p-type semiconductor-metal contact.
Here, they recombine with a hole that was either created as an electron-hole pair on the p-type side of the solar cell, or are swept across the junction from the n-type side after being created there.

To understand the electronic behavior of a solar cell, it is useful to create a model which is electrically equivalent, and is based on discrete electrical components whose behavior is well known. An ideal solar cell may be modeled by a current source in parallel with a diode; in practice no solar cell is ideal, so a shunt resistance and a series resistance component are added to the model. The resulting equivalent circuit of a solar cell is shown on the left. Also shown on the right, is the schematic representation of a solar cell for use in circuit diagrams.

1. Cost may not cover lifespan savings unless a preferential feed-in tariff is offered by the grid network. But this depends on location and energy prices.
2. Solar electricity is often initially more expensive than electricity generated by other sources.
3. Solar electricity is not available at night and is less available in cloudy weather conditions. Therefore, a storage or complementary power system is required.
4. Limited power density: Average daily insulation in the contiguous U.S. is 3-7 kWh/m² and on average lower in Europe.
5. Solar cells produce DC which must be converted to AC (using a grid tie inverter) when used in currently existing distribution grids. This incurs an energy loss of 4-12%.

1. The 89 pet watts of sunlight reaching the earth's surface is plentiful - almost 6,000 times more than the 15 terawatts of average power consumed by humans. Additionally, solar electric generation has the highest power density (global mean of 170 W/m²) among renewable energies. Solar power is pollution free during use. Production end wastes and emissions are manageable using existing pollution controls. End-of-use recycling technologies are under development.
2. Facilities can operate with little maintenance or intervention after initial setup.
3. Solar electric generation is economically superior where grid connection or fuel transport is difficult, costly or impossible. Examples include satellites, island communities, remote locations and ocean vessels.

4.When grid-connected, solar electric generation can displace the highest cost electricity during times of peak demand (in most climatic regions), can reduce grid loading, and can eliminate the need for local battery power for use in times of darkness and high local demand; such application is encouraged by net metering. Time-of-use net metering can be highly favorable to small photovoltaic systems.
5. Grid-connected solar electricity can be used locally thus reducing transmission/distribution losses (transmission losses were approximately 7.2% in 1995).
6. Once the initial capital cost of building a solar power plant has been spent, operating costs are extremely low compared to existing power technologies.

7. Compared to fossil and nuclear energy sources, very little research-money has been invested in the development of solar cells, so there is much room for improvement. Nevertheless, experimental high efficiency solar cells already have efficiencies of over 40% and efficiencies are rapidly rising while mass production costs are rapidly falling


1) Programmable Output Wattage.
2) Programmable Charging Current.
3) Extendable Output Wattage by use Dual Battery.
4) User interface with the help of remote.
5) LCD display which displays, Input AC mains Voltage, Load voltage, Load c/n, AC Mains Frequency, Inverter frequency. LCD also displays Charge of Battery and Battery Backup with Time remaining to discharge the Battery.
6) Switching between Inverter mode and Charging mode within 10ms which avoids restarting of computer.

As far as application areas are concerned our inverter is so feasible, energy saving and easy to install that it can be used anywhere in the houses, schools, colleges, hospitals, industries and institutions etc.
1) Uninterrupted Power Supply.
2) AC Motor Control.
3) Mobile AC power Supplies.
4) High-voltage direct current (HVDC) power transmission.
5) Emergency Power Supplies for EPABX, Biomedical Instruments.

To overcome the ever increasing demand of electrical energy. By changing the program stored in inverter we can change the Frequency of Inverter and it can be used for Induction Heating. Inverters convert low frequency main AC power to a higher frequency for use in induction heating. Our inverter then changes the DC power to high frequency AC power.
A variable-frequency drive controls the operating speed of an AC motor by controlling the frequency and voltage of the power supplied to the motor. An inverter provides the controlled power. In most cases, the variable-frequency drive includes a rectifier so that DC power for the inverter can be provided from main AC power. Since an inverter is the key component, variable-frequency drives are sometimes called inverter drives or just inverters. Our Inverter can be used by changing its Program.