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Screenshot of my desktop showing my design in PCB artist

Top layer tracks are in red, bottom layer tracks in brown

Microprocessor Control part simulation in PROTEUS

PCB After adding components

PCB board after etching of artwork

PCB artwork from top in clockwise direction

1. Top silkscreen
2. Double sided copper pcb
3. Top side layout
4. Bottom side layout

BLOCK DIAGRAM of SYSTEM DESIGN

An approximate maximum transfer point can then be obtained by switching at a constant ratio
of Vout/Voc.

My PV modules are “Joy Solar” panels each rated 200W, 24V DC.
They are connected three in series to give Voc (an open circuit voltage)
of maximum 90V at peak irradiance. These series strings are then run in parallel
I experimented with different pulse widths ranging from 0.6 to 1 of Voc
and finally settled for 0.8

This was the point I achieved a maximum power transfer.

The method chosen by me is number five – the constant voltage method.

Each manufacturer’s PV array has what is known as an IV curve i.e. a curve
showing the maximum current that can be supplied at a particular voltage
from the panel. At some point along this curve is the maximum power transfer point.
The point showing maximum current at maximum voltage
this point is known as the knee of the IV curve.

This is shown below.

Objectives:
Considering the high cost of commercially available MPPT based solar charge controllers,
I decided to build one for myself at a much lower cost and secondly, to have customizable features.

Methodology:
Solar charge controllers are majorly DC buck converters.
There are several methods of achieving MPPT based charge controllers.

These briefly are:
Perturb and observe, Incremental conductance, Current Sweep Method, Constant voltage.
The first four methods involve storing the PV (photovoltaic) array Voc (Open circuit voltage) /current
against the controller output voltage Vout/current with varying pulse widths applied to the buck converter.
The stored points are then compared and that with the maximum power transfer value is then used to
switch the semiconductors in the controller for a fixed interval after which the process is repeated.