Combining modern high-power semiconductor devices with constantly improving magnetic materials opens up the possibility to replace bulky low-frequency transformers with a new medium voltage medium frequency conversion structure. While there are still challenges to be addressed related to these, so called power electronic transformers, a steadily increasing development effort is evident and considered in various contexts. Traction applications seem to be the first ones, where proliferation of these new power electronic converters, are expected. In this application field substantial weight and volume reduction could be achieved, providing additional functionality at the same time. In this paper experimental results obtained from a laboratory scale prototype of a power electronic transformer are presented, focusing primarily on the control system design and also considering specific traction requirements. This prototype was built to support full-size converter development.