I think what you are asking is can you refresh a the data from a PowerPivot model without having to open it in Excel and refresh it there.
You can automatically refresh PowerPivot data in SharePoint. I believe there is a limit that you can only refresh the data once a day.
Locate the workbook on SharePoint, click the drop-down arrow next to it, and choose Manage PowerPivot Data Refresh. Follow the instructions from the link from there. If you don't have that option, check that PowerPivot for SharePoint is installed and enabled.
Prerequisites:
- You must have Contribute level of permission or greater on the workbook to create a data refresh schedule.
- You must have Contribute level of permission or greater on the
workbook to create a data refresh schedule.
- The account that performs the refresh must be a Windows domain user
account.
- External data sources that are accessed during data refresh must be
available and the credentials you specify in the schedule must have
permission to access those data sources.
- The workbook must be checked in at the time the refresh operation is
finished.
- The SharePoint server that you publish to may or may not have the
same data providers you used to import the data. SharePoint 2010 is a
64-bit environment. If you used 32-bit Excel to create PowerPivot
workbooks, you must work with your server administrator to ensure
that the 32-bit version of any data providers used by your workbook
are also installed on the server.