Power Bi access token

Hello there,

I need to generate a token for embedding power bi report, but i am not using power bi embed for this and I wont be performing authorization. 

since its not power bi embed,

var embedToken = PowerBIToken.CreateReportEmbedToken(this.workspaceCollection, this.workspaceId, report.Id,"username",new string[] { "role1", "role2", "role3" });

isnt helping.

how do i go abt this, I got the embed url for the report but a valid access token is a must.

Thanks in advance