Single-Phase Line Frequency Commutated Voltage Source Inverter Suitable for Fuel Cell Interfacing

The paper describes a single-phase DC-AC topology for interfacing DC sources with the utility grid. In particular, the application to fuel cells is considered. The converter operates without batteries or any other energy storage device, so island mode operation is not possible. The commutation of the power switches is at the line frequency. This gives the converter several interesting properties such as: negligible switching losses, negligible EMI generation and higher reliability compared to PWM inverters (due to the much simpler control circuitry). Moreover, thanks to a suitable modulation strategy, the current injected into the grid presents almost unity displacement factor in a wide power range.