Power Bi dashboard embedded iframe keeps asking for login after every one hour

I have a java program that retrieve the embedded PBI dashboard report through and I am displaying it in a html page. 

Embedded iframe has a login button which prompt user id and password. After successful login the report is displayed. The problem is that the report keeps asking for a login every 1-2 hours. I was wondering whether there is a way to increase the session time. I want single sign on facility. Can we increase session time by any means?

Any help would be much appreciated!