PV MPPT FLC using Boost DC-DC Converter

I am simulating a solar panel system using MPPT FLC. I want to ask why most of the models I refer to on the internet use a 20 ohm load for this method.

In reality, when I try to change to any other arbitrary load, the simulation graph shows very strong oscillations and is not optimal.

And the optimal load for a 213.15W panel is 3.95 ohms, from what I know.

Answer 1

[Joel Van Sickel]

Can you share your model? Is this a shipping example or something off of file exchange or a model that you built yourself? The whole point of MPPT is that it should work across a variety of loads. That is actually the whole point of it. For different loads and different irradiances, you need to be able to adjust the system to extrac the maximum power. However, there is also not an ideal resistance, as you stated, when using MPPT, because MPPT can adjust the output voltage to draw the appropriate current from the solar panel. So for a 4 ohm load compared to a 20 ohm load, MPPT should drop the voltage by a factor of 5 to keep the current out of the solar cell the same. It sounds like potentially the closed loop isn't tuned well for a large change in load current.

[Nguyen]

HI, Thank you for your replying.

I always thought that the MPPT FLC system was superior to PNO and INC in every case when simulating with Matlab, but in my example here, I realized that FLC is only superior at a 20-ohm load, while for 30 and 40-ohm loads, it doesn't even perform as well as PNO or INC. Even when increasing the number of solar panels. Could it be that this MPPT FLC algorithm is not good enough?

Answer 2

[Salvador Shinji]

Hello, First of I want to say I really liked your model, and second I was wondering if you could help me with a couple of questions.

In your MPPT algortih, Why do you multiply your E by 1/100000 and CE by 1/1000 and also the output by 1/10?

Do you have any paper can I citate ?

[Nguyen]

I'm sorry, I've only looked up this model online. I don't really know how to set the appropriate values for E, CE, and D. However, with this multiplier, the model above seems to want to constrain the values of E, CE, and D within the range of (-1, 1).

If you really understand the value limits of the membership functions E CE and D in this FLC model, please explain to me.