Buck boost converter for MPPT

Discussion in 'The Projects Forum' started by kewzj, Nov 11, 2013.

  1. kewzj

    Thread Starter New Member

    Oct 30, 2013
    8
    0
    Hi,

    I'm currently doing a solar and wind hybrid controller, with a solar panel of 17.6V and 3.69A at max power and I'm currently searching on suitable IC acting as a buck boost converter to regulate the voltage before feeding the voltage into a battery storage system of 12 V input. There is an MPPT algorithm being used to control the duty cycle of the buck boost converter. Are there any suggestions of any chip can be use as a buck boost converter with an input from MPPT to control the duty cycle?
     
  2. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    Generally it's not worth running MPPT on a 12v panel into a 12v lead acid battery.

    Your panel has max output at 17.6v, and the battery may be charged at 14.5v. An MPPT running at 85% (which is about typical for such a small voltage change) would give you;
    IN (65.12W) 17.6v 3.7A
    OUT (55.35W) 14.5v = 3.8A

    so the total gain from the complexity of MPPT and SMPS gives only 0.1A more current into the battery!

    Just use a linear regulator, or buy a typical 5A or 10A 12v solar regulator from ebay for cheaper than you can make it, and they come with little displays too showing volts, amps etc...
     
  3. kewzj

    Thread Starter New Member

    Oct 30, 2013
    8
    0
    However, a buck boost converter can step up the voltages and its efficiency is higher compared to linear regulator.
     
  4. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    A buck-boost SMPS is less efficient than a buck SMPS, and there is no need to "step up the voltage" as the 12v panel always runs at a higher voltage (at max eff) than the battery does under any charge condition.

    What is the effect you are wanting to achieve?
     
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