Yaakov receives two invitations to go down to Egypt. One comes from Yosef, who invites him to come and live in Goshen, where Yosef will be able to sustain him and his household during the remaining years of the famine. The second invitation is issued by Pharaoh, encouraging Yaakov and all of his household to partake of all the goodness of the land of Egypt. In order to illustrate the dual nature of the descent to Egypt, the Torah makes use of both of Yaakov's names – Yaakov and Yisrael, and a dual description of their dwelling – Goshen and Egypt. 

Yaakov - name change
Yaakov Descends to Egypt
Courtesy of the Virtual Beit Midrash, Yeshivat Har Etzion