A low-cost fuel-cell (FC) power electronic system (PES) for residential loads

We describe a low-cost power-electronics system (PES) for a solid-oxide fuel cell (SOFC) power system. The PES consists of a (DC/DC) zero-ripple boost converter (ZRBC) followed by a soft-switched multilevel high-frequency (HF) inverter and a single-phase cycloconverter. The zero input ripple-current feature of the boost converter improves the durability of the SOFC, while reducing the size and cost of the inductor. The multilevel arrangement of inverter switches reduces the voltage stress on the switches is sine-wave pulse-width modulated SPWM and has phase-shifted ZVS turn-on. The cycloconverter, switches at line frequency when the power transfer is active; otherwise, it switches at the switching frequency (20 kHz). A 1 kW prototype of the proposed PES achieved an overall efficiency of 91%. We present a detailed description of the operation of the PES and its key features and advantages. Finally, experimental results showing the performance and operation of the PES are demonstrated.