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.

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.

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.

BLOCK DIAGRAM of SYSTEM DESIGN

PCB artwork from top in clockwise direction

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

PCB board after etching of artwork

PCB After adding components

Microprocessor Control part simulation in PROTEUS

Screenshot of my desktop showing my design in PCB artist

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

Highside mosfet approx. 32khz,12v peak-peak drive signal on Oscilloscope set to differential mode

Fully assembled and installed.

Some changes had to be made, number of toroids in output inductor was increased from two to three
to reduce system losses due to heat

input/output terminals were melting at above 20A so I removed them and soldered wires directly to the board

initial backlit blue background LCD replaced with more passive green background LCD

Controller at night time
relays disconnect the controller from the PV array

Some useful design tools

1. InductorRing program from Vladmir Denisenko (search google)

2. Power stage designer tool from Texas Instruments

Hi bro, nice information. But i was expecting you were building it from scratch not prebuild. Anyway do inbox me ur contact, we could work on something together

@mrnestyy1985:

It was built from scratch by me. The design is not exactly rocket science.
The issue of being prebuilt or not was discussed in the previous version of this post before the recent loss of data on nairaland.

Hi engr @nisol. This is a great design and full of innovations. I work for a solar based marketing company as an engineer and am happy to learn how the components I sell are really made. My number is 07030098944 and email is ui_coole@yahoo.com. I would like to meet you and learn more from you. Give me a look in sometime, please.

Hi Mr. nisol. Really nice design you've done. I really appreciate your input, especially you presentation.

A while ago, I did some research into the workings of the MPPT technique. I read a lot of application notes, notably from manufacturers like Microchip, Atmel and Intersil. But I never really got round to doing any work related to it largely because of other engagements. But with what you have done and presented here, you have just helped sparked my interest in that again. Though, I am interested in SMPS technology in general.

Out of curiosity, I would like to ask: Have you done any work on offline SMPS designs before?

Thank you much much!!

@usisky

Once you control the the on/off duration of semiconductor switches in a
to influence the output of a power circuit, you have an SMPS (switch mode power supply).

This project involves SMPS technology in two places.

(1) the DC-DC stepdown (48V -12v/5v) flyback converter
(2) buck converter switched at 40khz.

In the not to distant future I will post more detailed SMPS designs.

@nisol

Peace and thanks for your response.

Yes! I understand that it is "switch mode" technology too. I was just curious to know if you've done designs on "offline" SMPS. I am very much interested in that, hence, my asking.

Your contribution has been immense. I hope some day we'll get to do some designs together.

Thanks Sir.

Dear Sir,

how can I get software and PCB file

Regards

Datta

Dear sir,

how can I get software file, PCB, schematic diagram.

Laco

my oga o rep you oooooo.......u dey build mppt cc!!!!! am highly impressed for these,how is the function of the cc now or u build it for someone?

Dear sir,

how can I get software file, PCB, schematic diagram.

Lalasticlacla...fp oo

Version II

LETS TALK.
gadgetpalaz@gmail.com
07051584918

Advanced Mppt Controller, using incremental conductance, interleaved to 180 degree out of phase for better performance, up to 80 amp 96v , displays parameters on LCD and battery voltage auto selectable. ##updated##

Impressive........

Please sir, How can I get the schematic diagram and pcb of this Design. Thanks

this is encouraging