High step-up continuous input current LCCT-Z-source inverters for fuel cells

Z-source inverters (ZSIs) are suited for applications which require a large range of voltage gain, such as in fuel cells. The present paper extends the concept of ZSIs. New type high step-up LCCT-Z-source inverter dedicated for fuel cells is proposed in the paper. Compared to recently proposed modifications of basic Z-source inverter the new topology has the advantages of available continuous input current, improved boost ratio and simple topology. Thanks to application of transformer with turns ratio higher than one the proposed LCCT-Z-source can operate with lower shoot-through ratio and higher modulation index compared to ZSI. The existence of two built-in DC-current-blocking capacitors connected in series with transformer windings prevents the transformer core from saturation. Simulation and experimental results are provided to verify the reliability of the proposed topology.