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
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.