Utility interactive fuel cell inverter for distributed generation: design considerations and experimental results

Distributed generation (DG) systems are potential solutions for efficient and economic integration of many non-conventional energy sources into the existing power grid. Among various alternative power sources, fuel cells are strong candidates for DG applications. Suitable interfacing of such resources into the DG network critically depends on design and performance of the power conversion stage. In this work, the design and experimental results of a utility interactive fuel cell inverter system for DG application are discussed. A series resonant DC-DC converter coupled with a sinusoidal pulse width modulated (SPWM) inverter is considered as the power stage. While connected to the grid, the inverter works in the current controlled mode. Stand-alone mode of operation is maintained through a voltage-controlled scheme. A DSP (TMS320F2812) based feedback control architecture and aspects of utilizing controller area network (CAN) fieldbus within the DG network are discussed. Compatibility with the existing DG standards, cost issues, and performance indices are analyzed with reference to experimental results. Control, communication, and challenges of integrating fuel cell systems into the distribution grid are also highlighted