Besides the safety, IPP pays big attention to the reliability of the ASDEX Upgrade pulsed power supply systems. Most of the equipment is between 25 and 40 years old. To avoid long down-times during an experimental campaign, fault-prone components have to be treated early. This becomes even more important with the increased availability requirements due to the AUG participation in the EURATOM Medium Sized Tokamak (MST) program. For this reason flywheel generator EZ3 recently received a new drive converter with integrated control. Most challenging was to adapt a modern converter, originally designed for wind turbines, towards a drive system for a flywheel-motorgenerator system. To identify the layout of the controller and the control parameters accurate modelling and comprehensive simulations were performed. This effort paid off during commissioning and measuring results verified the calculated design values. Finally, the system shows excellent performance during AUG plasma experiments.