Hello
You can refer to the following documentation to get an idea on how to solve this problem. This PV System Model example shows how to model a three-phase grid-connected solar photovoltaic (PV) system. If you are looking for a sample model of a three phase inverter, this Three-Phase Inverter Voltage Control model example may be helpful.
Since this seems like a homework assignment, if you can provide the model you've made to solve the problem and ask a specific question about where you're facing difficulty, we may be able to provide some guidance.
If you aren't sure where to start because you're not familiar with how to model in Simulink, I suggest you start with the Simulink Onramp tutorial (https://www.mathworks.com/learn/tutorials/simulink-onramp.html) to quickly learn the essentials of Simulink.
