Two DOF controller for parallel operation of fuel cell power generator with power grid

Parallel operation of a fuel cell power generator is considered in connection with the power grid. For a smooth power flow control between the local fuel cell generator system and the power grid, we propose a connection topology along with a two degree of freedom (DOF) controller. The two DOF controller inherently contains the inverse dynamics of the plant in the feedforward path. Hence, it enables us to achieve a wide bandwidth. In the feedback loop, it employs a PI controller which compensate the disturbance action caused by load change or islanding/reconnection. The proposed controller reacts fast enough to the changes in load or grid connection states, and, as a result, it looks efficient in supplying to load the constant voltage without phase jump. Also, it is shown to be possible to continuously receive/supply power from/to the grid. The implementing concept of two DOF controller and parallel operational strategy are illustrated. Finally, simulation results done by MATLAB are shown.