Patent ID: 8890365

Claim:
A fuel cell device for producing electrical current to an electrical network, and for a parallel connected arrangement to the electrical network, wherein the fuel cell device comprises: means for switching the fuel cell device off from an electrical network when a malfunction occurs in the electrical network; a power transformer having a control circuit and a current controlled power stage to input electrical current to the electrical network when the fuel cell device has been parallel connected to electrical network, said control circuit forming a phase reference signal for inputting of the electrical current; and a controllable load for maintaining a power stability of the fuel cell device, wherein said power transformer will change the fuel cell device, using the phase reference signal, to a switched off operation mode from the electrical network for performing voltage controlled operation of the power transformer, and said controllable load for maintaining power stability between the voltage controlled power transformer and other parts of the fuel cell device and, when the malfunction has vanished from the electrical network, said power transformer will change the fuel cell device, using the phase reference signal, to a switched on operation mode to the electrical network for performing current controlled operation of the power transformer.