Spend some time on Google Scholar looking at published work in the area. You will get the help you need to move forward. Your question is very specific, which means this may be a project you have been assigned to. It is unlikely that someone will provide the exact help you are looking for. There are many aspects to your project, such as PLL, VHDL, and Grid-connected inverter. You will find books and online tutorials on all these topics. It is up to you to apply the knowledge and carry out the project.