How will you be providing the portgroup names ? In a CSV file ?
If yes, you could do something like
$vds = Get-VDSwitch -Name MyVDS
Import-Csv C:\portgroup-names.csv | %{
New-VDPortgroup -VDSwitch $vds -Name $_.Name -NumPorts 32
}
This assumes that your CSV looks like
Name
pg1
pg2
pg3