Simulink Error - While Irradiance change in PV Panel

Hello,

I am trying to analyse various MPPT algorithm under partial shading in pv panel while changing irradiance. I can simulate partial shading with constant irradiance using MPPT - PandO algorithm.( one panel 1000 w/m2, other one 800 w/m2, other one 600 w/m2 etc). But I need change irradiance during simulation. For example, firstly all panels have the same irradiance then irradiance should change at certain time. I used signal builder for each panel. ( The picture below shows irradiance 1000 w/m2 to 600 w/m2).

Unfortunately, I got the following error when I simulated.

I tried to solve the error;

• Switch the line search based algorithm
• Reduce the fixed-sep size of the solver
• Reduce and increase sample time
• select and unselect ''break algebaic loop in internal model'' in PV Panel block Parameters ( get NaN output)

My Simulink Model

I need your expertise to solve the problem. Thank you in advance for your kind help.