The PowerShell script below allows you to run a Veeam backup.
This type of script can be used with a schedule task to initiate a backup.
# Load cmdlet Veeam
Add-PSSnapin VeeamPSSnapin
# Disconnect old session
Disconnect-VBRServer
# Connect Veeam Server
Connect-VBRServer -User "DOMAIN\administrator" -Password "password"
# Get job by Name
$bkjob = Get-VBRJob -Name "name of job"
# Start job
Start-VBRJob -Job $bkjob
# Disconnect session
Disconnect-VBRServer