This is a very basic script. You can use this with-in you own script or you
can write a funtion on it. This script using WMI and using the class
Win32_NetworkAdapterConfiguration. then using the RenewDHcpLease and
ReleaseDHCPlease methods of the class.
To know more about this script visti this link: http://newdelhipowershellusergroup.blogspot.in/2012/04/ip-address-release-renew-using.html