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

Discussion in 'General Electronics Chat' started by Mahmoud23, Jun 3, 2016.

  1. Mahmoud23

    Thread Starter New Member

    Jun 2, 2016
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    0
    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 ?
     
  2. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    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.
     
  3. Mahmoud23

    Thread Starter New Member

    Jun 2, 2016
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    0
    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 ?
     
  4. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    What is the capacity in amp-hours of this battery?
     
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