This is one of those things you would expect to have a native function in Hyper_v/Powershell. As far as i know it does not. This is how i get around it.
$GetVM = Get-VM -ComputerName localhost
Foreach ($vm in $GetVM)
{
echo $vm.name
Get-vm -name $vm.name | Get-VMHardDiskDrive | Get-VHD | fl path
}