simulate this circuit – Schematic created using CircuitLab

I have a circuit in Simulink that consist PV array and push-pull converter. The load is a simple resistor and with MPPT I extract the max power from the PV module at any load(resistor value)or Irradiation changes.

At the max power point, the panel voltage=37.9 V and the current= 8.3 A.

The problem is this: When I use load R=533.3333 ohm with MPPT I am getting max power(with the voltage and current above and the duty cycle=30%) from the panel and transmit it to the load with 95% efficiency. The Vout=400V and Pout=300 W.

However, when I changed the load R=200 ohm with mppt I am still getting the same max power from the panel(the duty cycle= 9%) but I can't transmit it to the load. There is a huge voltage drop. (Vout becomes 200 V scale. The voltage drop can be seen at the transformer also) The current is the same as the R=533.333 ohm situation.

The situation is similar with irradiation change. When it drops the Mppt can find the new max power point but at the load, there is a huge power loss.

I think the problem causes because of the capacitors. When I don't use any output capacitor there is no voltage drop anywhere. But I don't know the reason of this problem exactly and how can I solve it. If anybody has an idea and shared with me I would appreciate.

Ps1: the paramaters of the circuit are: Primer turns=100

Seconder turns=1100

Input Capacitor=100e-6 F

Output Capacitor= 47 e-6 F

Output Inductor=1e-6 H

At the final of the project, the input voltage from panel can vary between 30 and 40 V.

PS2: Due to a problem of my computer or the internet I cannot upload any image.

closed as unclear what you're asking by Dave Tweed Sep 14 at 19:12

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  • 2
    No circuit = no answer. – Andy aka Sep 14 at 15:26
  • I added a schematic from this site. But actually i don't understand this kind of language. I tried to explain everything clearly and the question is long as you can see. Also i had stated that i could not attach any image. But the answer i received "No circuit=no asnwer" :))))) It is interesting and annoying actually. I don't know if there is a specific rule about adding circuit may be there is but i had kindly noted before posting that i could not add anything. Anyway sorry for bothering you. – user391130 Sep 15 at 16:37
  • And "on hold" thing. Hahahahah What is it that you don't understand in the question??? – user391130 Sep 15 at 16:39
  • I solved the problem. A snubber circuit was the lack of system. When I add snubber problem was solved. For people who need an help to a similar problem. – user391130 Sep 18 at 14:56