In the last years the interest towards Power Electronic Transformers (PET) is increasing. These new conversion apparatuses perform either voltage transformation or power quality functions, using power electronics both on primary and secondary sides of a transformer operating at medium frequency. In the technical literature are proposed several circuital configurations, with different control strategies. However these are not exhaustive yet, especially if is considered that PET can be utilized in a lot of different fields of application. Simplicity, effectiveness and high-resolution of the control are important aspects which can strongly improve performance of PETs. The paper presents an overview of the main topologies of converters for PET with a Medium Frequency (MF) transformer, and the control strategies are analyzed.