onedrive refreshWITHOUT gateway

[jmdh]

I have spent several days trying to understand how a report (using data in a Table format in Excel 2016 stored on OneDrive pro) created with PowerBI Desktop (stored on OneDrive Pro) and published on the PowerBI service is refreshed in the service.

I want to understand if any refresh works without using the Gateway as i understood it should.
1 when i modofy and change the Pbix

2 when i change the data in the Excel file 

If so what are the restrictions if any.

Many thanks before i get mad.

PS by the way the Gateway works fine but if you uninstall it you get into serious problems