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Solar optimizer and Square wave inverter

Discussion in 'Renewable Energy' started by Mohammed Kaddoura, Jun 17, 2015.

  1. Mohammed Kaddoura

    Mohammed Kaddoura New Member

    Joined:
    Jun 17, 2015
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    Hello everyone, as i am new to this forum, i would like start with you with my graduation project.
    Its supposed to be a Solar optimizer and a square wave inverter with a solar sun tracking system
    but i didn't have enough time to finish the solar tracking system so i will continue it later.

    as you can see I'm using a PWM circuit and also a current meter which is connected to the optimizer and the optimizer is connected to a microcontroller which will control the optimizer system.

    I have added another Micro controller for an LCD to show the voltage and the current coming from the Solar Panel

    I have almost finished programming it but didn't test it yet

    Aright so,,, Hope you like it.. If you have any questions you can ask :)


    [​IMG]

    [​IMG]

    [​IMG] [​IMG] [​IMG]

    Red led = Battery is Charging
    Green = battery finished charging
    Yellow = Inverter is on and 220v is on the output, i am using variable resistance to control the frequency and voltage.
    in my country frequency is 50 hz and 220v

    [​IMG]
    The output voltage



    [​IMG]
     
  2. Tony Stewart

    Tony Stewart Well-Known Member Most Helpful Member

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    Location:
    Richmond Hill , ON Canada near Toronto
    Lack of specs and test results may indicate your lack of response.

    MPT is often just 80% of Voc +/-5% depending on solar level so tracking gain is often minimal, just match PV voltage to buck regulator to extract max power.

    How did you choose and did you track solar input ? with a photo diode matrix? or hunt and find? How much power was wasted?

    Tracking often consumes more power than it saves, so optimization requires an energy loss/gain budget and offers no gain in overcast conditions. Did you analyze this?

    What output impedance Zout, did you choose/ get for inverter ?
    This affects load regulation directly and affects performance on reactive and nonlinear loads ( L, C, CR )

    Have you ever consider dental floss or tie wraps for neater wiring?

    Did you ever examine near field EMI using the scope probe & gnd clip as a loop antenna? You should, to understand how inductive feedback can cause EMI issues and unintended emissions.

    For accurate signal capture use two matched probes (A-B) that give a flat line when connected to a noisy square wave. Sometimes twisting probe cables helps, but better is straight coax to R tapped divider to Coax connectors on board with 50 Ohm terminator on scope or remove probe clip and ground wire and only use tip and barrel between sign/gnd between two small test points spaced to fit calibrated 10:1 scope probe tip & ring.

    Otherwise inverter analysis can be messy with 100 MHz ringing signals.

    Did you ever analyze effective series resistance ( incremental) from source to loads?
    THis is very important to understand design issues. PV impedance as a current source is not ( remember MPT is 80% of Voc, max power transfer occurs at what source impedance. THen Buck regulator effective imedance matching in/out. Battery ESR, Bulk and RF Cap ESR, bridge ESR (RdsON), turns ratio, etc.

    Then do a Power loss budget analysis for conduction loss, eddy current loss, skin effect losses ( remember to use Litz wire for transformers) , impedance mismatch losses , etc.

    Then a sensitivity analysis is normally done for all critical parameters, temp, voltage, RdsOn, Current sense limit / Core I_max ratio etc., ESR & RLC values etc. if one ever wants to optimize for production.
     
    Last edited: Jun 21, 2015
  3. MikeMl

    MikeMl Well-Known Member Most Helpful Member

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    Also, learn how to focus a camera, and resize the images so they are no more than ~250kb each before posting them. If a picture is worth a 1000 words, an electrical schematic diagram is worth at least 10o of your pictures.
     

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