How to model MPPT technique with PID controller

Question

I need to model a MPPT algorithm with a PID controller at Simulink. The model will feed the gates of two mosfets of a push-pull converter.

I have to extract max power from PV and have a fixed voltage(400V) at the output of push-pull converter even the irradiation decreases. I probably use incremental conductance or P&O algorithm for MPPT but i haven't decided yet.

I have read some papers about this and acording to them, i need to measure Vpv and Ipv from panel and put them into a "something"(matlab fuction, or a different type algorithm) then output of this "something" will be referance voltage and finally give this referance and feedback from converter output into a PID controller and produce a duty cycle for mosfets.

I understand the concept but i don't know how to write the code or model the algorithm which transform the Vpv and Ipv into referance voltage.( i mean the relationship for this change, because the panel output will be like 35 V and the output voltage should be 400V) Also i want to ask what load should i use for having fixed voltage at the output of converter? (I may model the load as if it is DC bus with constant voltage and according to power the output current varies but again i could not figure out how to do)

I am using this as my final project at university and so far couldn't get help about it so i will be appreciate any help.

• Harry Svensson: Will you cite us in the report afterwards?
• Andy aka: Very similar to your earlier question except now you are considering that MPPT is your problem.
• Gökhan: @HarrySvensson yes of course this is a ofiicial thesis and it will be done according to rules.
• Gökhan: @Andyaka hahahah, my earlier concern is still alive , i am changing resistor value which is necessary for getting desired voltage value at the same time changing the irradiation. This is not my real need but for now it should be enough the practise MPPT algorithm
• Andy aka: Do you understand this: researchgate.net/profile/Susovon_Samanta2/publication/276404676/…

Answer 1

I am also doing a project like yours. And I am having the same problem as you. Btw i have progressed a little bit. You can use simulinks function block to write the code. You shall find it under used defined function block. You also have to use memory block so that previous samples data is available to you. You can use delay too. But then you have to specify sampling frequency. First with the use of zero order hold block take sample of current and voltage- feed them to memory block,then calculate dv,di ,feed them to simulink used defined function ,add the PID to the output of function. One thing though, for PID tuning you may need state space model of your converter.