A device for converting direct voltage from an electrochemical store or a fuel cell to alternating voltage, includes a two-stage design having a single DC/DC converter stage for generating an intermediate circuit voltage from the output voltage of the electrochemical store or the fuel cell, which converter stage converts, in particular raises, the direct voltage in a wide input voltage range directly to an intermediate circuit voltage with which a DC/AC converter stage can be operated to generate the alternating voltage. The single DC/AC converter stage generates the alternating voltage from the intermediate circuit voltage. The invention further relates to a method for actuating a device for converting direct voltage from a store or energy generator into alternating voltage for feeding into a supply network.