On Thu, Apr 10, 2025 at 03:11 AM, <kmesne@...> wrote:
Hi, I am trying to understand how MPPT works in a buck converter with resistive load by doing an LTSpice simulation. I have a PV model which works very accurately with a current sink load. And it works perfectly as in figure below (I can also change irradiance and its very accurate with the datasheet)
Hello,
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What are your panel parameters (Vov, Isc, Vmpp, Impp etc.)? What kind of algorithm are you using (Perturb and Observe (PnO), Incremental Conductance (InC) etc.)? What is your MPPT frequency? For how much time are you running your simulation?
I am assuming that it is a PnO algorithm. Your system cannot reach Maximum Power Point (MPP) if it is under light load condition. I have attempted MPPT simulations in MATLAB and there I never experienced what you mention as: "I cant get the left part and I think this is logical because with a resistor at the output load there is no way that voltage will increase but current stay constant because resistor is a passive load.".
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What if the time needed by your simulation to converge is more than the run itself? In such a case as well you will never reach MPP. My suggestions are:
1) Increase the power consumption at the load end (somehow bring your system operating point from no load/partial load to full load).
2) Increase the simulation run time.
?
BTW, just curious, are you using the average values of your PV voltage and current as input to your MPPT algorithm?
With Regards,
Ankit
