Dear Erika

Please find the attached simulations.First one is the basic PV, buck converter,battery bank (as load) and MPPT system.Second one is the modeling of the PV array based on the attached paper.I have done those simulations in MATLAB R2015a platform.Please let me know if you need any further information.

thank you so much for your help. i very appreciate it

hello Amal C Sunny ,

can you check on my simulink circuit ,please?I do not know why i am getting errors and the simulation is taking time.

Thanks in advance

Hello Erika

I have gone through your simulation, before coming to the error part, I have a few comments on your complete system.

(1) You have a PV at the input side, and resistive load at the buck converter output.First of all the open loop system (as per your simulation, giving duty from a pulse generator at 5%, 40kHz) is not correct, because you are not defining the power either on input side nor on output side. Now you might be confused with the operation of buck converter from either a battery or a regulated DC power supply. But remember, in both of these sources your input side voltage is fixed (as a stiff source), by giving a fixed duty your output voltage will be adjusted (assuming CCM mode), so your load power will be Vout^2/R (Vout=Output voltage,R=load resistance).Now the converter will draw current from the source so that power balance is maintained, means Vin*Iin=Vout*Iout(neglect the losses).Now suppose your input is PV, means it is not a stiff voltage source, so you must define either the input power or output power. If you want to define the input power you can control the PV voltage at some value (say at maximum power point), so your input side power will be Vmpp*Impp (remember the PV curve), now you might be thinking what happens at the output because you have connected some fixed value of resistor as load.At the output your power will be Vout^2/R, since R is fixed your output voltage get adjusted so that the power balance is maintained.In short you do not have a control over the output voltage.

Vmpp*Impp= Vout^2/R (neglect the losses).Now suppose if you are controlling output voltage means your output side power is fixed Vout^2/R (because both Vout and R is fixed), so your input side PV power (PV voltage and Current) gets adjusted so that power balance is maintained.

(2) If you want to control either input or output you have to control the duty ratio of your switch by using a closed loop control scheme.You have only one control variable that is the duty ratio of your switch as I have done in my previous simulations.

(3)Regarding your simulation please consider the above points and the following.

(a) To change solver settings,Ctrl+E>Solver>Type (either fixed step or variable),chose a solver method and go to additional parameters please enter your step time if you have chosen fixed step.Now come back to your simulation page please change the powergui block in either continues or discreet (please enter sampling time) as well.You will get an idea of these values from my previous simulations.

(b) As per your simulation, inside the PV array number of parallel and series connected stings are so high, so the power rating also.Please take a single PV panel, make calculation based on power balance on both input and output of your converter as per above equations.

(c) For controlling the input voltage (PV power indirectly) sense the PV voltage and current, add a closed loop control scheme,so that your duty ratio gets controlled. You can do the same for controlling the output voltage by sensing it.