A novel grid interface, optimized for utility-scale applications of photovoltaic, wind-electric, and fuel-cell systems

Utility-interactive photovoltaic, wind-electric and fuel-cell systems are being planned at sufficiently large power levels. The technical and economic feasibility of such systems partially depends on the reliability, cost, and the efficiency of their grid interface. Here, a novel interface, which takes advantage of the system conditions in a utility-scale application is presented. The paper describes the basic principle of operation and characteristics. It is shown that the Total Harmonic Distortion in the line currents meets the 5 percent limit recommended by the IEEE. 519-1992, with one-third the high frequency switch kVA ratings as compared to other topologies. Various options are discussed for utility-scale applications. Simulation results for a 25 kW unit are presented. The new conceptual circuit is validated by a prototype hardware design at the 2.2 kW power level