By using ExMerge.exe builtin utility provides by Microsoft, you can use this inbuilt tool easy export EDB file into MS Outlook PST file format.
To export mailboxes to PST using powershell first of all you have to add snapins to powershell by using the command like-
Microsoft.exchange.management.powershell.e2010
And after that you can use command like-
New-MailboxExportRequest Command as given below
New-MailboxImportRequest -Mailbox username -IsArchive -FilePath \\SERVER01\PSTFiles\Archives\username\Archive2012.pst
Note: The EDB file must be mounted and should be in healthy form to perform the conversion using this method. In case if you have corrupted EDB, you can use Expert suggested solution:
In the meantime, if you don't get satisfactory results with this cmd, then you can go for a alternative solution available in the form of EDB to PST Converter which is a complete package for recovery of corrupted Exchange database and conversion to PST files.This utility easily solves all type of corruption issues of exchange files.