Design and modeling of a power conditioning system for the hybrid fuel-cell/turbine power plant.

This thesis presents the model of a power conditioning system (PCS) for the hybrid direct fuel-cell with turbine (DFC/T) power plant. It regulates voltage, current and power transmitted from the hybrid DFC/T power plant to utility grid. The proposed system consists of DC/DC converters, a grid-connected sinusoidal pulse width modulation (SPWM) DC/AC inverter, and an LCL filter. To regulate and stabilize the DC link voltage, DC/DC converter with PI controller is adopted. With three-phase SPWM inverter, both active and reactive power flow can be controlled. Both conventional proportional integral (PI) and the improved fuzzy PI control schemes are proposed. The LCL filter can greatly reduce the current total harmonic distortion (THD). Theoretical analysis and modeling methodologies are presented. Simulation results validate the proposed system and demonstrate that the proposed PCS can follow a dynamic load and reduce the current THD to 1.65%, which is much lower than IEEE standard of 5%.