51163743 solar battery charger with mppt using microcontroller

8/22/2019 51163743 Solar Battery Charger With MPPT Using Microcontroller

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Solar Battery Charger With

MPPT Using A Microcontroller

C.Suchetha


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Photo Voltaic Cells

Photo Voltaic cells are devices that generate

electromotive force as a result of absorption of

ionizing radiation.


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Advantages of PV cells

Direct conversion of solar radiation to

electricity

Reliable, Maintenance Free

Quite, compatible

Durable


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Disadvantages of PV cells

Low conversion efficiency

High fabrication cost

Continues supply is not possible


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Three essential approaches to

overcome the drawbacks Improving manufacturing process of solar

arrays

Controlling insolation input to PV arrays

Utilization of output electric power of solar

arrays


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Conventional battery charging

system


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Maximum Power Point Tracking

MPPT is an electronic tracking in which thecontroller compares the panel output with the

battery input and pushes the operating point tothe maximum power point.

MPPT is used in PV systems to continuously

tune the system so that it draws maximumpower from the solar array irrespective ofweather or load conditions.


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Types of MPPT Techniques

Lookup table method

Perturbation & observation (P & O)method

Computational method


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Perturbation & Observation Method


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Types of P & O Method

Comparison with a constant reference

value

Incremental Conductance Method

Feed Forward MPPT Controller


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Present System

An MPPT control system has beendeveloped ,consisting a Buck converterwhich is controlled by a microcontroller

based unitThe main difference between this and

existing methods is that the power outputfrom the panel is directly used to controlthe converter output.


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MPPT is more effective under theseconditions

Winter or cloudy days

Cold weather

Low battery charge


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Block diagram

Th bl k di i t f f


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The block diagram consists of four

blocks.

PV array

Buck converterBattery

Microcontroller


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The PV array specification used in this

project is as follows

Maximum voltage: 35 volts

Open circuit voltage: 44 volts

Maximum current: 15 amps


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A sealed lead acid battery is used in this

project. The specification are

Battery voltage : 24 volts

Battery capacity : 150 Ah


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Buck converter


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ATMELs ATmega 128L low-power

consumption, CMOS microcontroller withbuilt in EEPROM, FLASH memory, ADC,

PWM generator is used.

Advanced RISC Architecture 128K Bytes of In-System reprogrammable

Flash

In-System Programming by On-chip BootProgram


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Schematic Diagram


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Software Development Tools

The tools used in developing this softwareWinAVR GCC compiler and AVR Studio 4 IDEfor AVR series of microcontroller.

The C program written is complied using theWinAVR GCC compiler. This compiler convertsthe C file to the file with extension .cof. This .coff

file is used to build, simulate and debug theprogram using the AVR Studio 4. The AVRStudio 4 generates .hex file which isdownloaded to microcontroller.


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Main Program


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MPPT Charge Function

Trickle Charge F nction


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Trickle Charge Function


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The testing was done for three different

conditions

1. Connection of the panel directly to the

battery.

2. Connection of the panel to the batterythrough an ordinary charger.

3. Connection of the panel to the battery

with MPPT.


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Results

From the results obtained the percentage

of the power wasted the three different

conditions is

23.8% when directly connected.

18.63% when connected through a

ordinary charger.

11.38% when connected to a MPPT

charger.


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Conclusion

The MPPT technique assures

maximization of energy transfer to the

battery bank.

The battery lifetime is increased because

the battery is operating at higher state of

charge.


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Future Extensions

This design can be further be worked upon

to include GSM for remote controlling of

the load.

This control system can be used for a grid

connected system also.

51163743 solar battery charger with mppt using microcontroller

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