using the name should work without parameters. I think it should auto use the first parameter.
May have to just force it to decide with -Name "xxxxx"
get-help get-vm
NAME
Get-VM
SYNOPSIS
This cmdlet retrieves the virtual machines on a vCenter Server system.
SYNTAX
Get-VM [[-Name] <String[]>] [-Datastore <StorageResource[]>] [-Location <VIContainer[]>] [-NoRecursion] [-Server <VIServer[]>] [-Tag <Tag[]>] [<CommonParameters>]
Get-VM -Id <String[]> [-Server <VIServer[]>] [<CommonParameters>]
Get-VM [[-Name] <String[]>] [-Server <VIServer[]>] [-Tag <Tag[]>] [-VirtualSwitch <VirtualSwitchBase[]>] [<CommonParameters>]
Get-VM -RelatedObject <VmRelatedObjectBase[]> [<CommonParameters>]