A Novel Converter System for Fuel Cell Distributed Energy Generation

To interface the fuel cells (FCs) to grid/loads a DC/AC energy conversion system is required with the capability to act as an energy buffer for matching generator-load dynamics. A new power converter design is proposed based on cascade connection of a DC/DC and a DC/AC converter. The DC/DC converter has to control the FC current ripple and regulate the power flow from the FC. It is characterized by only two main switches of low side type, operated with an interleaved control technique which requires the use of two boost inductance chokes. Such a control strategy provides input current ripple cancellation, which is mandatory in fuel cell systems. A regenerative active clamp circuit is also used in order to prevent high peak voltages on the two main switches, maintaining a high efficiency. The proposed DC/DC converter is tested on a laboratory prototype and represents a new cost effective topology, able to operate under a wide range of input voltages and load conditions with high efficiency