Designing a MPPT solar tracking system with Buck converter to charge a 12v battery

Thread Starter

Mahmoud23

Joined Jun 2, 2016
2
Hi Everyone,
i am designing a MPPT solar tracking system with a 20w panel that generate max voltage 17.5v and max current 1.14A .Voc 21.9. Isc 1.22.And i am trying to design a buck converter to be able to get an output voltage to charge the battery of 12v and 2A . and i wanted to know how can i design it coz i cant get an accurate value for the Inductor and the Capacitor .and is it better to use buck converter only or do i have to use buck-boost converter? i am using an Arduino Uno for controlling the PWM , so can generate enough frequency from it to be able to use to for the switch? . if anyone can help please ?
 

ErnieM

Joined Apr 24, 2011
8,020
That can't be done as you are trying to pull more power out of the converter than the panel can supply.

As a general rule MPPT is not called for with low voltage panels as the switching losses exceed what could be gained.

Also, an MPPT inverter must begin with a stage that draws current continuously, such as a boost converter. That gives you more voltage then you need, so you need a seccond stage to drop it down.

With a ton of work an expert may get the losses to equal a simple linear scheme, which is what I recommend you do.
 

Thread Starter

Mahmoud23

Joined Jun 2, 2016
2
That can't be done as you are trying to pull more power out of the converter than the panel can supply.

As a general rule MPPT is not called for with low voltage panels as the switching losses exceed what could be gained.

Also, an MPPT inverter must begin with a stage that draws current continuously, such as a boost converter. That gives you more voltage then you need, so you need a seccond stage to drop it down.

With a ton of work an expert may get the losses to equal a simple linear scheme, which is what I recommend you do.
So you mean i have to use a buck-boost converter ?
and i cant do an MPPT inverter with the 20w panel i have to use more due to the losses
so how can i charge the battery faster with this 20w panel do i need anything more than the microcontroller and the buck converter ?
 
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