Device for converting electrical energy and method for operating such a device

The device has a two-stage structure with a single direct current (DC)/DC converter stage (3) for generating an intermediate circuit voltage from an output voltage of electrochemical storage or a fuel cell. The stage directly converts the DC voltage in a wide input voltage range to the circuit voltage. A DC-/alternating current (AC) converter stage generates AC voltage, and the DC/DC converter stage comprises a DC/DC converter device (41) that is galvanically separated and has a high-frequency transformer. The DC/AC converter stage generates the AC voltage from the circuit voltage. An independent claim is also included for a method for controlling a device for converting a direct current voltage from a storage i.e. electrochemical storage, and a fuel cell in to an alternating current.